US20100004499A1 - Methods And Devices For Minimally-Invasive Extraocular Delivery of Radiation To The Posterior Portion Of The Eye - Google Patents

Abstract

Methods and devices for minimally-invasive delivery of radiation to the posterior portion of the eye including a cannula comprising a distal portion connected to a proximal portion and a means for advancing a radionuclide brachytherapy source (RBS) toward the tip of the distal portion; a method of introducing radiation to the human eye comprising inserting a cannula between the Tenon's capsule and the sclera of the human eye and emitting the radiation from the cannula on an outer surface of said sclera.

Description

CROSS REFERENCE
• This application claims priority to U.S. non-provisional application Ser. No. 12/350,079 filed Jan. 7, 2009, the specification of which is incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
• The present invention is directed to minimally-invasive methods and devices for introducing radiation to the posterior portion of the eye for treating and/or managing eye conditions including macula degeneration.
BACKGROUND OF THE INVENTION
• Several diseases and conditions of the posterior segment of the eye threaten vision. Age related macular degeneration (ARMD), choroidal neovascularization (CNV), retinopathies (e.g., diabetic retinopathy, vitreoretinopathy), retinitis (e.g., cytomegalovirus (CMV) retinitis), uveitis, macular edema, and glaucoma are several examples.
• Age related macular degeneration (ARMD) is the leading cause of blindness in the elderly. ARMD attacks the center region of the retina (i.e., macula), responsible for detailed vision and damages it, making reading, driving, recognizing faces and other detailed tasks difficult or impossible. Current estimates reveal that approximately forty percent of the population over age 75, and approximately twenty percent of the population overage 60, suffer from some degree of macular degeneration. “Wet” or exudative ARMD is the type of ARMD that most often causes blindness. In wet ARMD, newly formed choroidal blood vessels (choroidal neovascularization (CNV)) leak fluid and cause progressive damage to the retina. About 200,000 new cases of Wet ARMD occur each year in the United States alone.
• Brachytherapy is treatment of a region by placing radioactive isotopes in, on, or near it. Both malignant and benign conditions are successfully treated with brachytherapy. Lesion location dictates treatment technique. For the treatment of tumors or tumor beds in the breast, tongue, abdomen, or muscle capsules, catheters are inserted into the tissue (interstitial application). Radiation may be delivered by inserting strands of radioactive seeds into these catheters for a predetermined amount of time. Permanent implants are also possible. For example, in the treatment of prostate cancer, radioactive seeds are placed directly into the prostate where they remain indefinitely. Restenosis of coronary arteries after stent implantation, a non-malignant condition, has been successfully treated by placing a catheter into the coronary artery, then inserting a radioactive source into the catheter and holding it there for a predetermined time in order to deliver a sufficient dose to the vessel wall. Beta emitters, such as phosphorus 32 (P-32) and strontium 90 (Sr-90), and gamma emitters, such as iridium 192 (Ir-192), have been used. The Collaborative Ocular Melanoma Study (COMS), a multicenter randomized trial sponsored by the National Eye Institute and the National Cancer Institute demonstrated the utility of brachytherapy for the treatment of ocular cancers and/or tumors. The technique employs an invasive surgical procedure to allow placement of a surface applicator (called an episcleral plaque) that is applied extraocullarly by suturing it to the sclera. The gold plaque contains an inner mold into which radioactive iodine 125 (I-125) seeds are inserted. The gold plaque serves to shield the tissues external to the eye while exposing the sclera, choroid, choroidal melanoma, and overlying retina to radiation. The plaque remains fixed for a few days to one week in order to deliver approximately 85 Gy to the tumor apex.
• Radiotherapy has long been used to treat arteriovenous malformations (AVM), a benign condition involving pathological vessel formation, in the brain. An AVM is a congenital vascular pathology characterized by tangles of veins and arteries. The dose applicable to the treatment of neovascularization in age-related macular degeneration (WAMD) by the devices described herein may be based on stereotactic radiosurgery (SRS) treatment of arteriovenous malformations (AVM). SRS is used to deliver radiation to the AVM in order to obliterate it, and radiation is highly effective for AVM treatment. The minimum dose needed to obliterate an AVM with high probability is approximately 20 Gy. However, small AVMs (<1 cm) are often treated with a higher dose (e.g., 30 Gy) because when treating small AVMs, a significant amount of eloquent brain (e.g., brain regions wherein injury typically causes disabling neurological deficits) is not exposed to the high dose of radiation. The reported SRS doses correspond to the dose received at the periphery of the AVM, while the dose at the nidus (center) may be up to a factor of 2.5 times greater than the reported SRS dose.
• The vascular region involved in WAMD is much smaller than even the smallest AVM, thus the effective doses are expected to be similar to the highest doses used for AVM. Studies of irradiation of WAMD have shown that greater than 20 Gy are required, although one study indicates some response at 16 Gy. Without wishing to limit the present invention to any theory or mechanism, the devices described herein for WAMD are expected to be effective by delivering a nearly uniform dose to the entire region of neovascularization or by delivering a nonuniform dose which may vary by a factor of 2.5 higher in the center as compared to the boundary of the region with minimum doses of 20 Gy and maximum doses of 75 Gy. A report using radiosurgery for macular degeneration describes that a dose of only 10 Gy was not effective (Haas et al, J Neurosurgery 93, 172-76, 2000). In that study, the stated dose is the peripheral dose with the center being about 10% greater. Furthermore, the study results were severely plagued by retinal complications.
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the devices of the present invention are advantageous over the prior art. For example, since SRS employs external photon beams which easily penetrate the ocular structures and pass through the entire brain, the patient must be positioned such that the beams may be directed towards the macula, making the geometric uncertainties of delivery a few millimeters. The devices of the present invention have geometric and dosimetric advantages because they may be placed at the macula with submillimeter accuracy, and the beta radioisotope may be used to construct the radiation source with predominately limited range.
• The present invention features methods and devices for minimally-invasive delivery of radiation to the posterior portion of the eye.
SUMMARY OF THE INVENTION
• The present invention features a method of irradiating a target of an eye in a patient. The method comprises inserting a cannula into a potential space under the Tenon's capsule. The cannula comprises a radionuclide brachytherapy source (RBS) at a treatment position, whereby the RBS is positioned over the target as shown, for example, inFIG. 5. The RBS irradiates the target. In some embodiments, the treatment position is a location on or within the cannula (e.g., the middle of the cannula, along the length or a portion of the length of the cannula, near the end of the cannula). In some embodiments, the treatment position comprises a window on the cannula. In some embodiments, the treatment position is configured to receive an RBS. In some embodiments, an indentation tip and/or a light source is disposed at the treatment position.
• In some embodiments, the Tenon's capsule guides the insertion of the cannula and provides positioning support for the cannula. In some embodiments, the target is a lesion associated with the retina. In some embodiments, the target is located on the vitreous side of the eye. In some embodiments, the target (e.g., lesion) is a benign growth or a malignant growth.
• In some embodiments, method comprises inserting a cannula between the Tenon's capsule and the sclera of the eye, for example at the limbus, a point posterior to the limbus of the eye, a point between the limbus and the fornix. In some embodiments, any appropriate cannula may be used in accordance with the present invention for the subtenon procedure. In some embodiments, cannulas that may be used in accordance with the present invention include flexible cannulas, fixed shape cannulas (or a combination of a flexible and fixed shape cannula), and cannulas which are tapered to provide a larger circumferential surface in the portion of the cannula which remains in the Tenon's capsule upon insertion, thereby providing additional positioning support to maintain the cannula over the target. In some embodiments, the arc length of the distal portion of the cannula is suitably of sufficient length to penetrate the Tenon's capsule and extend around the outside of the globe of the eye to a distal end position in close proximity to the macular target.
• In some embodiments, the cannula employed in the inventive subtenon procedure comprises a distal portion, which is a portion of the cannula that is placed around a portion of the globe of the eye. The cannula has a radionuclide brachytherapy source (“RBS”) at a treatment position (e.g., in the middle of the cannula, near the end, in the middle, along the length of the cannula). The cannula may be “preloaded” with an RBS or “afterloaded”. For example, in some embodiments, the RBS is loaded into the cannula before the cannula is inserted. For example, in U.S. Pat. No. 7,070,554 to White, the brachytherapy device comprises a “preloaded” radiation source, i.e., a radiation source affixed at the tip of the device prior to the insertion of the device into the eye. In some embodiments, the RBS is loaded into the cannula after the cannula is inserted. For example, seeFIG. 6, where the radiation source is loaded to near the tip after the cannula has been inserted into the eye. Also, for example, seeFIGS. 1C and 1D where the radiation source is advanced from the handle/pig after positioning the distal portion. The method further comprises positioning the RBS over the sclera portion that corresponds with the target (e.g., lesion), and the RBS irradiates the target (e.g., lesion) through the sclera.
• The cannula may be of various shapes and sizes and constructed from a variety of materials. In some embodiments, the cannula is a fixed shape cannula. In some embodiments, the cannula is a flexible cannula, including an endoscope-like device. In some embodiments, the cannula is tapered (e.g., a larger circumferential area in the portion which remains in the Tenon's capsule upon insertion.
• In some embodiments, the target is a lesion associated with the retina. In some embodiments, the target (e.g., lesion) is a neovascular lesion.
• Neovascular lesions of wet macula degeneration generally cannot be seen via indirect/direct opthalmoscopy. In some embodiments, an angiogram (or other localizing technology such as optical coherence tomography, ultrasound) is performed, for example before the cannula is inserted between the Tenon's capsule and sclera. The angiogram may help locate the cannula and the target (e.g., lesion), and direct the cannula to the correct position over the target. For example, while localizing the target (e.g., lesion) via the surrounding landmarks and in reference to the previously obtained angiogram, the cannula may be directed to a precise position. In some embodiments, the cannula comprises a window and/or an orifice, and the window/orifice of the cannula can be placed directly behind the target (e.g., lesion). In some embodiments, a photograph or video may be taken during the procedure to document the placement of the cannula.
• In some embodiments, an angiogram, optical coherence tomography, ultrasound, or other localizing technology is performed, for example after the cannula is inserted between the Tenon's capsule and sclera. The localizing technology (e.g., angiogram) may help locate the cannula and the target (e.g., lesion), and direct the cannula to the correct position over the target. For example, while visualizing the target (e.g., lesion) via the localizing technology (e.g., angiogram), the cannula may be directed to a precise position. In some embodiments, the cannula comprises a window and/or an orifice, and the window/orifice of the cannula can be placed directly behind the target (e.g., lesion). In some embodiments, the localizing technology (e.g., angiogram) is a real-time procedure. In some embodiments, localizing technology is optical coherence tomography or ultrasound or other technology. In some embodiments, a photograph or video may be taken during the procedure to document the placement of the cannula.
• The RBS can be constructed to provide any dose rate to the target. In some embodiments, the RBS provides a dose rate of between about 0.1 to 1 Gy/min, between about 1 to 10 Gy/min, between about 10 to 20 Gy/min, between about 20 to 30 Gy/min, between about 30 to 40 Gy/min, between about 40 to 50 Gy/min, between about 50 to 60 Gy/min, between about 60 to 70 Gy/min, between about 70 to 80 Gy/min, between about 80 to 90 Gy/min, between about 90 to 100 Gy/min, or greater than 100 Gy/min to the target (e.g., lesion).
• The present invention also features a method of irradiating a target (e.g., lesion associated with the retina) of an eye in a patient. The method comprises inserting a cannula into the potential space under the Tenon's capsule (e.g., between the Tenon's capsule and the sclera) of the eye. In some embodiments, the cannula is inserted at the limbus, a point posterior to the limbus, or a point between the limbus and the fornix. In some embodiments, the cannula comprises a distal portion (e.g., a portion of the cannula that is placed over a portion of the globe of the eye). In some embodiments, the distal portion of the cannula is placed on or near the sclera behind the target (e.g., a lesion on the retina). A radionuclide brachytherapy source (RBS) is advanced through the cannula, for example to the treatment position (e.g., in the middle of the cannula, near a tip/end of distal portion), via a means for advancing the RBS. (In some embodiments, the means for advancing the RBS comprises a guide wire. In some embodiments, the means for advancing the RBS comprises a ribbon). The target is exposed to the RBS. The RBS may be loaded before the cannula is inserted or after the cannula is inserted.
• The cannula may be constructed in various shapes and sizes. In some embodiments, the distal portion is designed for placement around a portion of the globe of the eye. In some embodiments, the distal portion has a radius of curvature between about 9 to 15 mm and an arc length between about 25 to 35 mm. In some embodiments, the cannula further comprises a proximal portion having a radius of curvature between about the inner cross-sectional radius of the cannula and about 1 meter. In some embodiments, the cannula further comprises an inflection point, which is where the distal portion and the proximal portions connect with each other. In some embodiments, the angle θ₁between the line l₃tangent to the globe of the eye at the inflection point and the proximal portion is between greater than about 0 degrees to about 180 degrees.
• The present invention also features a hollow cannula with a fixed shape. The cannula comprises a distal portion for placement around a portion of the globe of an eye, wherein the distal portion has a radius of curvature between about 9 to 15 mm and an arc length between about 25 to 35 mm. The cannula further comprises a proximal portion having a radius of curvature between about the inner cross-sectional radius of the cannula and about 1 meter. The cannula further comprises an inflection point, which is where the distal portion and the proximal portions connect with each other. In some embodiments, the angle θ₁between the line l₃tangent to the globe of the eye at the inflection point and the proximal portion is between greater than about 0 degrees to about 180 degrees.
• In some embodiments, once the distal end of the distal portion is positioned within the vicinity of the target, the proximal portion is curved away from the visual axis as to allow a user to have direct visual access in the eye.
• The present invention also features a cannula with a fixed shape. The cannula comprises a distal portion for placement around a portion of a globe of an eye and a proximal portion connected to the distal portion via an inflection point. In some embodiments, the distal portion has a shape of an arc formed from a connection between two points located on an ellipsoid, wherein the ellipsoid has an x-axis dimension “a”, a y-axis dimension “b,” and a z-axis dimension “c.” In some embodiments, “a” is between about 0 to 1 meter, “b” is between about 0 to 1 meter, and “c” is between about 0 to 1 meter. In some embodiments, the proximal portion has a shape of an arc formed from a connection between two points on an ellipsoid, wherein the ellipsoid has an x-axis dimension “d”, a y-axis dimension “e,” and a z-axis dimension “f.” In some embodiments, “d” is between about 0 to 1 meter, “e” is between about 0 to 1 meter, and “f” is between about 0 to 1 meter. In some embodiments, the angle θ₁between the line l₃tangent to the globe of the eye at the inflection point and the proximal portion is between greater than about 0 degrees to about 180 degrees.
• The present invention further features a “fine positioning” surgical technique. For example, after inserting a cannula into a potential space under a Tenon's capsule of the eye of the patient, the surgeon observes the position of (through the patient's pupil via a “visual axis”, see for exampleFIG. 5) the treatment position of the cannula in a posterior pole of the eye, and adjust it accordingly to accurately localize it over the target as shown inFIG. 5. In some embodiments, the physician observes the position of the treatment position and adjusts it while the patient's eye is in a primary gaze position. A primary gaze position is when the patient looks straight ahead. In some embodiments, the physician observes the position of the treatment position and adjusts it while the patient's eye is in any one of the following position: elevated, depressed, adducted, elevated and adducted, elevated and abducted, depressed and adducted, and depressed and abducted. By seeing the position of the treatment position, the surgeon can adjust the cannula to position the treatment position over a target, as shown for example inFIG. 5. In some embodiments, one of the advantages of the present “fine positioning” technique is that it allows for convenient and accurate placement of the RBS at the appropriate location behind the eye. In some embodiments, the fine positioning technique allows for placement of the cannula with millimetric precision.
• In some embodiments, the inventive methods of the present invention can be performed under general or local anesthesia (e.g., retro or peribulbar) to the eye. When a general or local anesthesia is administered to the patient's eye, the eye will be in a primary position, and the patient has no motor movement of the eye. Accordingly, after the general or local anesthesia, the patient's eye will be in a primary gaze position, i.e., looking straight forward. The present inventive surgical methods and device allow for the surgeon to administer the radiation accurately to the target in the eye while the eye is in a primary gaze position. In some embodiments, the advantage of being able to perform the treatment while the patient's eye is in a primary gaze position is that it does not require the surgeon to perform additional surgical steps to secure the eye to a non-primary gaze position, as such securing steps may traumatize the eye.
• The present invention also features a method of delivering radiation to an eye. The method comprises irradiating a target (e.g., a lesion associated with the retina, a target on the vitreous side of the eye, a benign growth, a malignant growth) from an outer surface of the sclera. In some embodiments, the target receives a dose rate of greater than about 10 Gy/min.
• The present invention also features a method of irradiating a target (e.g., a target/lesion associated with the retina) of an eye in a patient. The method comprises placing a radionuclide brachytherapy source (RBS) at or near a portion of the eye (e.g., sclera) that corresponds with the target. The RBS irradiates the target through the sclera, wherein more than 1% of the radiation from the RBS is deposited on a tissue at or beyond a distance of 1 cm from the RBS. In some embodiments, about 1% to 15% of the radiation from the RBS is deposited on a tissue or beyond a distance of 1 cm from the RBS. In some embodiments, about less than 99% of the radiation from the RBS is deposited on a tissue at a distance less than 1 cm from the RBS.
• The methods of the present invention also allow for delivering a smaller volume/area of radiation as compared to other procedures. For example, a radionuclide brachytherapy source (“RBS”) in the shape of a disk can provide a controlled projection of radiation (e.g., a therapeutic dose) onto the target, while allowing for the radiation dose to fall off quickly at the periphery of the target. This keeps the radiation within a limited area/volume and may help prevent unwanted exposure of structures such as the optic nerve and/or the lens to radiation. Without wishing to limit the present invention to any theory or mechanism, it is believed that low areas/volumes of irradiation enables the use of higher dose rates, which in turn allows for faster surgery time and less complications.
• Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art. Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 shows views of various fixedshape cannula100 according to the present invention.FIG. 1A shows a side view of a fixedshape cannula100 comprising adistal portion110, aproximal portion120, aninflection point130, and ahandle140. Also shown is atip200, thearc length185 of thedistal portion110, and thearc length195 of theproximal portion120.FIG. 1B shows a perspective view of the fixedshape cannula100 fromFIG. 1A.FIG. 1C shows thedistal region112 of thedistal portion110, themiddle region113 of the distal portion, awindow510, a seed-shapedRBS400, and aguide wire350 having adistal end320 wherein thewire350 is housed in thehandle140 of the fixedshape cannula100.FIG. 1D shows theguide wire350 extended through theproximal portion120 and thedistal portion110 of the fixedshape cannula100.FIG. 1E shows thecircle181 defined by the curvature of thedistal portion110, theradius182 ofcircle181, and the radius ofcurvature180 of thedistal portion110.FIG. 1F shows thecircle191 defined by the curvature of theproximal portion120, theradius192 ofcircle191, and the radius ofcurvature190 of theproximal portion120.
• FIG. 2 shows side views ofvarious tips200 ofdistal portions110 according to the present invention.Various tips200 may comprise anorifice500 or awindow510 and/or alight source610, and/or anindentation tip600.FIG. 2J illustrates amemory wire300 wherein thememory wire300 forms aflat spiral310 when extended from thetip200.FIG. 2K shows adistal chamber210 wherein amemory wire300 forms aflat spiral310 when extended into thedistal chamber210.
• FIG. 3 shows a side view of adistal portion110 and aproximal portion120 according to the present invention.
• FIG. 4 shows perspective views ofhandles140 according to the present invention.FIG. 4A shows ahandle140 comprising athumb ring810, wherein the handle comprises anon-wire plunger800.FIG. 4B shows ahandle140 comprising agraduated dial820.FIG. 4C shows ahandle140 comprising aslider830.FIG. 4D shows an example of a fixed shape cannula comprising aradiation shielding pig900 between theproximal portion120 and thehandle140. A seed-shapedRBS400 is attached to aguide wire350, and the seed-shapedRBS400 is housed within thepig900.
• FIG. 5 shows the insertion of an assembledfixed shape cannula100 according to the present invention. The fixedshape cannula100 comprises alocator160. Thehandle140 andproximal portion120 are out of thevisual axis220 of the physician and the patient. Tenon's capsule a layer of tissue running from the limbus anteriorly to the optic nerve posteriorly. The Tenon's capsule is surrounded anteriorly by the bulbar conjunctiva that originates at the limbus and reflects posteriorly into the tarsal conjunctiva at the conjunctival fornix.
• FIG. 6 shows the insertion of an unassembled fixedshape cannula100 according to the present invention, wherein thehandle140 and/orradiation shielding pig900 is attached to theproximal portion120 via aconnector150 after the fixedshape cannula100 is in place.
• FIG. 7 shows an example of a radionuclide brachytherapy source (“RBS”) (e.g., seed-shaped RBS400) inserted into a fixed shape cannula.
• FIG. 8 shows lateral radiation dose profile of various devices, including that of the present device (SalutarisMD). The graph represents an example of relative radiation doses (y-axis) measured at distances from the center of the target (x-axis). The SalutarisMD device presents a more rapid decline in radiation dose as the distance away from the target periphery (e.g., area within about 1 mm from center of target) increases.
• FIG. 9 shows a comparison of the insertion of a fixedshape cannula100 of the present invention (e.g., according to a posterior radiation approach) to the insertion of a device used for anintravitreal radiation approach 910.
• FIG. 10 is an illustration defining the term “lateral.” The drawing may be representative of a horizontal cross-section of an eye ball, wherein the target is the choroidal neovascular membrane (CNVM), the source is the radioactive source (e.g., seed-shaped RBS400), and the sclera is located between the source and the target.
• FIG. 11 shows an example of a radiation dose profile of a 1 mm Sr-90 source as measured laterally at a 1.5 mm depth.
• FIG. 12 shows an example of lines that are perpendicular to line l_Ras viewed looking above the RBS/target downward along line l_R.
• FIG. 13 shows an example of an isodose (e.g., the area directly surrounding the center of the target wherein the radiation dose is substantially uniform), perpendicular to line l_R, as viewed looking above the RBS/target downward along line l_R. In this example, the area wherein the radiation dose is substantially uniform extends up to about 1.0 mm away from the center of the target.
• FIG. 14A is a front cross sectional view of thedistal portion110 of the fixedshape cannula100 wherein the top of the fixed shape cannula100 (e.g., distal portion110) is rounded and the bottom is flat.FIG. 14B is a bottom view of thedistal portion110 ofFIG. 14A.FIG. 14C is a perspective view of an example of the RBS in the form of adisk405 having a height “h”406 and a diameter “d”407.FIG. 14D shows a variety of side cross sectional views of RBSs having various shapes (e.g, rectangle, triangle, trapezoid).FIG. 14E shows an example of a RBS comprising a disk-shapedsubstrate361. On thebottom surface363 of thesubstrate361 is anisotope362.FIG. 14F shows examples of rotationally symmetrical shapes. The present invention is not limited to the shapes shown inFIG. 14F.FIG. 14G shows an example of aradiation shaper366 comprising a window364 (e.g., rotationally symmetrically-shaped window). Thewindow364 is generally radio-transparent and theradiation shaper366 is generally radio-opaque. Radiation from a RBS is substantially blocked or attenuated by theradiation shaper366 but not thewindow364.
• FIG. 15 shows an example of anellipsoid450 with an x-axis dimension, a y-axis dimension, and a z-axis dimension.
• FIG. 16A shows a side view of theproximal portion120 of the fixedshape cannula100.FIG. 16B-D shows examples ofinner diameters171,outer diameters172, and aninner radius173 of a cross-section of theproximal portion120 of the fixedshape cannula100.
• FIG. 17 shows an example of angle θ₁425 which is betweenline l₃420 tangent to the globe of the eye at theinflection point130 and theproximal portion120
• FIG. 18A shows twodifferent planes P₁431 and P₂432.FIG. 18B showsplane P₁431 as defined by the normal to the plane n₁and plane P₂432 defined by the normal to the plane n₂.FIG. 18C shows examples of angles betweenP₁431 and P₂432
• FIG. 19A shows a perspective view of a fixedshape cannula100 wherein the cross section of thedistal portion110 and theproximal portion120 are generally circular.
• FIG. 19B is a perspective view of a fixedshape cannula100 wherein the cross section of thedistal portion110 and theproximal portion120 is flattened in a ribbon-like configuration.
• FIG. 20A shows a perspective view of a disk-shaped RBS inserted into a means for advancing the RBS toward thetip200 of the fixedshape cannula100.
• FIG. 20B is a perspective view of a plurality of cylindrical RBSs inserted into a means for advancing the RBS toward thetip200 of the fixedshape cannula100.
• FIG. 21 shows a perspective view of a well having radio opaque walls, and a radionuclide brachytherapy source is set in the well.
• FIG. 22 shows the radiation profiles where the intensity of the radiation at the edge falls off significantly, i.e., there is a fast fall of at the target edge. When a shielding is employed, the radiation fall off at the edge is faster compared to when there is no shielding.
DESCRIPTION OF PREFERRED EMBODIMENTS
• The present invention features methods and devices for minimally-invasive delivery of radiation to the posterior portion of the eye. Without wishing to limit the present invention to any theory or mechanism it is believed that the sub-tenon method of delivering radiation to the posterior portion of the eye of the present invention is advantageous for several reasons. For example, the sub-tenon procedure is minimally invasive and does not require extensive surgical dissections. Thus, this unique procedure is faster, easier, and will present fewer side effects and/or complications the prior art methods that otherwise require dissections. Moreover, the sub-tenon method may allow for simple office-based procedures with faster recovery times.
• The sub-tenon method also allows for the tenon's capsule and other structures (e.g., sclera) to help guide and hold the device in place when in use. Keeping the cannula in a fixed location and at a distance from the target during the treatment reduces the likelihood of errors and increases the predictability of dose delivery. In an intravitreal approach (e.g., irradiating the target area by directing the radiation from within the vitreous chamber from anteriorly to the retina of the eye back towards the target), a physician is required to hold the device in a fixed location and a fixed distance from the target in the spacious vitreous chamber (seeFIG. 9). It may be difficult for the physician to hold precisely that position for any length of time. Furthermore, it is generally not possible for the physician/surgeon to know the exact distance between the probe and the retina; he/she can only estimate the distance.
• The methods of the present invention direct radiation from the posterior side of the eye forwardly to a target; radiation is shielded in the back. Without wishing to limit the present invention to any theory or mechanism, it is believed that these methods will spare the patient from receiving ionizing radiation in the tissues behind the eye and deeper than the eye. A pre-retinal approach (e.g., irradiating the target area by directing the radiation from the anterior side of the retina back toward the target) irradiates the anterior structures of the eye (e.g., cornea, iris, ciliary body, lens) and has the potential to irradiate the tissues deeper than the lesion, such as the periorbital fat, bone, and the brain. An intravitreal radiation approach also has the potential to irradiate the tissues deeper than the lesion (e.g., periorbital fat, bone, brain) and also, in a forward direction, the lens, ciliary body and cornea.
• Prior to the present invention, radiotherapy as applied to the eye generally involves invasive eye surgeries. For example, an authoritative report in the radiation therapy industry known as the “COMS study” discloses a protocol that employs an invasive surgical procedure to dissect the periocular tissues and place the brachytherapy device. This is unlike the presently inventive minimally invasive subtenon method.
• The prior art has disclosed a number of brachytherapy devices and methods of using same for irradiating a lesion from behind the eye. However, these techniques do not employ the minimally invasive subtenon approach of the present invention. Upon reading the disclosures of the prior art, one of ordinary skill would easily recognize that the procedure being disclosed is quadrant dissection approach or a retro-bulbar intra-orbital approach, neither of which is the minimally invasive subtenon approach.
• The following is a listing of numbers corresponding to a particular element refer to herein:
• 100 fixed shape cannula
• 110 distal portion
• 112 distal region of distal portion
• 113 middle region of distal portion
• 120 proximal portion
• 130 inflection point
• 140 handle
• 150 connector
• 160 locator
• 171 inner diameter of cannula
• 172 outer diameter of cannula
• 173 inner radius of proximal portion
• 180 radius of curvature of distal portion
• 181 circle/oval defined by curve of distal portion
• 182 radius of circle/oval defined by curve of distal portion
• 185 arc length of distal portion
• 190 radius of curvature of proximal portion
• 191 circle/oval defined by curve of proximal portion
• 192 radius of circle/oval defined by curve of proximal portion
• 195 arc length of proximal portion
• 200 tip
• 210 distal chamber (disc-shaped)
• 220 visual axis of user
• 230 Tenon's capsule
• 235 sclera
• 300 memory wire
• 310 flat spiral
• 320 distal end of wire
• 350 guide wire
• 361 substrate
• 362 isotope (or “radionuclide”)
• 363 bottom surface of substrate
• 364 window of radiation shaper
• 366 radiation shaper
• 400 seed-shaped RBS
• 405 disk
• 406 height of disk
• 407 diameter of disk
• 410 radioactive source portion of wire
• 420 line l₃
• angle θ₁
• 431 plane P₁
• 432 plane P₂
• 450 ellipsoid
• 500 orifice
• 510 window
• 520 distal edge of orifice/window
• 600 indentation tip
• 610 light source
• 800 non-wire plunger
• 810 thumb ring
• 820 graduated dial
• 830 slider
• 900 radiation shielding pig
• 910 device used for intravitreal radiation approach
• As used herein, the term “about” means plus or minus 10% of the referenced number. For example, an embodiment wherein an angle is about 50 degrees includes an angle between 45 and 55 degrees
The Eye
• The mammalian eye is a generally spherical structure that performs its visual function by forming an image of an exterior illuminated object on a photosensitive tissue, the retina, The basic supporting structure for the functional elements of the eye is the generally spherical tough, white outer shell, thesclera235, which is comprised principally of collagenous connective tissue and is kept in its spherical shape by the internal pressure of the eye. Externally thesclera235 is surrounded by the Tenon's capsule230 (fascia bulbi), a thin layer of tissue running from the limbus anteriorly to the optic nerve posteriorly. The Tenon'scapsule230 is surrounded anteriorly by the bulbar conjunctiva, a thin, loose, vascularized lymphatic tissue that originates at the limbus and reflects posteriorly into the tarsal conjunctiva at the conjunctival fornix. Anteriorly thesclera235 joins the cornea, a transparent, more convex structure. The point where the sclera and cornea is called the limbus. The anterior portion of thesclera235 supports and contains the elements that perform the function of focusing the incoming light, e.g., the cornea and crystalline lens, and the function of regulating the intensity of the light entering the eye, e.g., the iris. The posterior portion of the globe supports the retina and associated tissues.
• In the posterior portion of the globe (referred to herein as the “posterior portion of the eye”) immediately adjacent the interior surface of thesclera235 lays the choroid, a thin layer of pigmented tissue liberally supplied with blood vessels. The portion of the choroid adjacent its interior surface is comprised of a network of capillaries, the choriocapillaris, which is of importance in the supply of oxygen and nutrients to the adjacent layers of the retina. Immediately anterior to the choroid lies the retina, which is the innermost layer of the posterior segment of the eye and receives the image formed by the refractive elements in the anterior portion of the globe. The photoreceptive rod and cone cells of the retina are stimulated by light falling on them and pass their sensations via the retinal ganglion cells to the brain. The central region of the retina is called “macula”; it is roughly delimited by the superior and inferior temporal branches of the central retina artery, it is mostly responsible for color vision, contrast sensitivity and shape recognition. The very central portion of the macula is called “fovea” and is responsible for fine visual acuity.
Novel Subtenon Approach to Introduce a Radionuclide Brachytherapy Source (“RBS”) to Posterior of Eye Globe
• The present invention features a method of introducing radiation to the posterior portion of the eye in a minimally-invasive manner (by respecting the intraocular space). Generally, the method comprises irradiating from the outer surface of thesclera235 to irradiate a target. The target may be the macula, the retina, thesclera235, and/or the choroid. In some embodiments, the target may be on the vitreous side of the eye. In some embodiments, the target is a neovascular lesion. In some embodiments, the target receives a dose rate of radiation of greater than about 10 Gy/min.
• In some embodiments, the method comprises using ahollow cannula100 to deliver a RBS to the region of thesclera235 corresponding to the target. (Although acannula100 of the present invention is used in the subtenon approach, other instruments such as an endoscope may also be used in accordance with present novel subtenon approach). Thecannula100 may be slid on the exterior curvature of the eye to reach the posterior portion of the eye. More specifically, in some embodiments, the method comprises introducing acannula100 comprising a RBS to the posterior portion of the eye between the Tenon'scapsule230 and thesclera235 and exposing the posterior portion of the eye to the radiation. Thecannula100 may be inserted at a point posterior to the limbus of the eye (e.g., any point between the limbus and the conjunctival fornix).
• The method may further comprise advancing a RBS through thecannula100 to thetip200 of thedistal portion110 via a means for advancing the RBS.
• In some embodiments, the method further comprises the step of exposing the target (e.g., macula) of the eye to the radiation. In some embodiments, the method comprises targeting a neovascular growth in the macula.
• In some embodiments, the RBS is placed in the subtenon space in close proximity to the portion of thesclera235 that overlays a portion of choroid and/or retina affected by an eye condition (e.g., WAMD, tumor). As used herein, a RBS that is placed “in close proximity” means that the RBS is about 0 mm to about 10 mm from the surface of thesclera235. In some embodiments, the radiation irradiates through thesclera235 to the choroid and/or retina.
• In some embodiments, the step of inserting thecannula100 between the Tenon'scapsule230 and thesclera235 further comprises inserting thecannula100 into the superior temporal quadrant of the eye. In some embodiments, the step of inserting thecannula100 between the Tenon'scapsule230 and thesclera235 further comprises inserting thecannula100 into the inferior temporal quadrant of the eye. In some embodiments, the step of inserting thecannula100 between the Tenon'scapsule230 and thesclera235 further comprises inserting thecannula100 into the superior nasal quadrant of the eye. In some embodiments, the step of inserting thecannula100 between the Tenon'scapsule230 and thesclera235 further comprises inserting thecannula100 into the inferior nasal quadrant of the eye.
• A RBS disposed at the distal end of acannula100 irradiates the target, and the target receives a dose rate of greater than about 10 Gy/min. In some embodiments, the RBS provides a dose rate of greater than about 11 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 12 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 13 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 14 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 15 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 10 to 15 Gy/min. In some embodiments, the RBS provides a dose rate between about 15 to 20 Gy/min. In some embodiments, the RBS provides a dose rate between about 20 to 30 Gy/min. In some embodiments, the RBS provides a dose rate between about 30 to 40 Gy/min. In some embodiments, the RBS provides a dose rate between about 40 to 50 Gy/min. In some embodiments, the RBS provides a dose rate between about 50 to 60 Gy/min. In some embodiments, the RBS provides a dose rate between about 60 to 70 Gy/min. In some embodiments, the RBS provides a dose rate between about 70 to 80 Gy/min. In some embodiments, the RBS provides a dose rate between about 80 to 90 Gy/min. In some embodiments, the RBS provides a dose rate between about 90 to 100 Gy/min. In some embodiments, the RBS provides a dose rate of greater than 100 Gy/min.
• In some embodiments, the distance from the RBS to the target is between about 0.4 to 2.0 mm. In some embodiments, the distance from the RBS to the target is between about 0.4 to 1.0 mm. In some embodiments, the distance from the RBS to the target is between about 1.0 to 1.6 mm. In some embodiments, the distance from the RBS to the target is between about 1.6 to 2.0 mm.
• In some embodiments, the RBS provides a dose rate between about 15 to 20 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 20 to 25 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 25 to 30 Gy/min to the target. In some embodiments the RBS provides a dose rate between about 30 to 35 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 35 to 40 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 40 to 50 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 50 to 60 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 60 to 70 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 70 to 80 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 80 to 90 Gy/min to the target. In some embodiments, the RBS provides a dose rate between about 90 to 100 Gy/min to the target. In some embodiments, the RBS provides a dose rate greater than about 100 Gy/min to the target.
• The present methods may be effective for treating and/or managing a condition (e.g., an eye condition). For example, the present methods may be used to treat and/or manage wet (neovascular) age-related macula degeneration. The present methods are not limited to treating and/or managing wet (neovascular) age-related macular degeneration. For example, the present methods may also be used to treat and/or manage conditions including macula degeneration, abnormal cell proliferation, choroidal neovascularization, retinopathy (e.g., diabetic retinopathy, vitreoretinopathy), macular edema, and tumors (e.g., intra ocular melanoma, retinoblastoma).
Advantages of Subtenon Procedure
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the novel subtenon methods of the present invention are advantageous over the prior art because they are less invasive (e.g., they do not invade the intraocular space), they require only local anesthesia, and they provide a quicker patient recovery time. For example, the technique of introducing radiation to the posterior portion of the eye by suturing a radioactive plaque on thesclera235 at the posterior portion of the eye requires a 360° peritomy (e.g., dissection of the conjunctiva), isolation of the four recti muscles and extensive manipulation of the globe. Furthermore, when the plaque is left in place and then removed a few days later, a second surgery is required. The methods of the present invention are easier to perform. Also, the intraocular method of exposing the posterior pole of the eye to radiation involves performing a vitrectomy as well as positioning and holding the radioactive probe in the preretinal vitreous cavity for a significant length of time without a stabilizing mechanism. This technique is difficult to perform, requires a violation of the intraocular space, and is prone to a number of possible complications such as the risk of retinal detachment, cataracts, glaucoma, and/or endophthalmitis. Because of the complexity of this technique, a fellowship in vitreoretina surgery is required. The methods of the present invention are easier to perform, minimally-invasive, and do not impose a risk of damage to the intraocular structures. Moreover, the methods of the present invention do not require additional vitreoretina fellowship training as these methods can be employed by any surgical ophthalmologist.
• As used herein, the term “minimally-invasive” method means a method that does not require that an instrument be introduced into the intraocular space (anterior, posterior, or vitreous chamber) of the eye for delivery of a radioactive source to the posterior portion of the eye or a method that does not require the suturing of a radioactive plaque on thesclera235 or extensive conjunctiva peritomy. For example, the minimally-invasive methods of the present invention only require a small incision of conjunctiva and Tenon'scapsule230 for inserting of acannula100 comprising a RBS to the posterior portion of the eye. The preferred approach is through the superotemporal quadrant, however entrance through the supero nasal, the inferotemporal or the inferonasal quandrant can be employed.
• The present invention features a method of introducing radiation to a human eye comprising the steps of inserting acannula100 between the Tenon'scapsule230 and thesclera235 of the human eye at a point posterior to the limbus of the human eye; wherein thecannula100 comprises adistal portion110 having a radius ofcurvature180 between about 9 to 15 mm and anarc length185 between about 25 to 35 mm; aproximal portion120; and a means for advancing a RBS toward thetip200 of the cannula100 (e.g.,tip200 of distal portion110); placing thedistal portion110 on or near thesclera235 behind a neovascular lesion; advancing the RBS to thetip200 of thedistal end110; and exposing the neovascular lesion to the RBS.
• In some embodiments, the area ofsclera235 exposed to the radiation is about 0.1 mm to about 0.5 mm in diameter. In some embodiments, the area ofsclera235 exposed to the radiation is about 0.5 mm to about 2 mm in diameter. In some embodiments, the area ofsclera235 exposed to the radiation is about 2 mm to 3 mm in diameter. In some embodiments, the area ofsclera235 exposed to the radiation is about 3 mm to 5 mm in diameter. In some embodiments, the area ofsclera235 exposed to the radiation is about 5 mm to 10 mm in diameter. In some embodiments, the area ofsclera235 exposed to the radiation is about 10 mm to 25 mm in diameter.
The Cannula
• The present invention features a fixedshape cannula100 for delivering a RBS to the back of the eye. The fixedshape cannula100 has a defined, fixed shape and comprises adistal portion110 connected to aproximal portion120 via aninflection point130. Thedistal portion110 of the fixedshape cannula100 is for placement around a portion of the globe of the eye. In some embodiments, thedistal portion110 of the fixedshape cannula100 is inserted below theTenon capsule230 and above thesclera235. In some embodiments, the fixedshape cannula100 is hollow.
• As used herein, a fixedshape cannula100 having a “fixed” shape refers to a fixedshape cannula100 that has a single permanent shape and cannot be manipulated into another shape. For example, the fixedshape cannula100 of the present invention has a “fixed” shape because it generally has one shape, whereas an endoscope does not have a “fixed” shape because it is flexible and can be manipulated into another shape. A fixedshape cannula100 having a “fixed” shape may also be constructed from a material that has some flexibility. Accordingly, when a pressure is applied onto the fixedshape cannula100 of the present invention it may bend. However, when the pressure is removed, the fixedshape cannula100 of the present invention may resume its original fixed shape or retain a portion of the deformation shape.
• In some embodiments, aninflection point130 may be defined as a point on a curve in which the sign or direction of the curvature changes. In some embodiments, there may be a straight portion of the fixed shape cannula between the distal portion and proximal portion. Accordingly, in some embodiments, the proximal and distal portions are separated at an inflection point where the curvature changes sign. In some embodiments, the proximal portion ends at a point where the curvature changes from a finite value to zero.
• In some embodiments, theinflection point130 helps to bend theproximal portion120 of the fixedshape cannula100 away from thevisual axis220 of the subject (e.g., patient) and of the user (e.g., physician) who inserts the fixedshape cannula100 into a subject. In some embodiments, the user may visualize the posterior portion of the eye of the subject by employing a coaxial opthalmoscopic device such as an indirect opthalmoscope or a surgical microscope while the fixedshape cannula100 is in place.
Distal Portion Dimensions of the Fixed Shape Cannula
• The dimensions of the globe of the eye are fairly constant in adults, usually varying by no more than about 1 mm in various studies. However, in hyperopia and myopia, the anteroposterior diameter of the globe may vary significantly from the normal measurement.
• The outer anteroposterior diameter of the globe ranges between about 21.7 mm to 28.75 mm with an average of about 24.15 mm (radius ranges from about 10.8 mm to 14.4 mm with an average of about 12.1 mm) in emmetropic eyes, whereas the internal anteroposterior diameter averages about 22.12 mm (radius averages about 11.1 mm). In high hypermetropia and myopia, the anteroposterior diameter is frequently as low as about 20 mm and as high as about 29 mm or more, respectively.
• The transverse diameter (e.g., the diameter of the globe at the anatomic equator measured from the nasal to the temporal side) averages about 23.48 mm (radius averages about 11.75 mm), and the vertical diameter (e.g., the diameter of the globe at the anatomic equator measured superiorly to inferiorly) averages about 23.48 mm (radius averages about 11.75 mm). The circumference of the globe at the anatomic equator averages about 74.91 mm. The volume of the globe of the eye averages between about 6.5 mL to 7.2 mL, and has a surface area of about 22.86 cm².
• Thedistal portion110 of the fixedshape cannula100 may be designed in a number of ways. In some embodiments, thedistal portion110 of the fixedshape cannula100 has anarc length185 between about 25 to 35 mm.
• In some embodiments, thearc length185 of the distal portion110 (e.g., length of the arc111 of the distal portion110) may be of various lengths. For example, hyperopic or pediatric patients may have smaller eyes and may require asmaller arc length185 of thedistal portion110. Or, for example, different insertion points (e.g., limbus, conjunctival fornix) of the fixedshape cannula100 may requiredifferent arc lengths185 of thedistal portion110. In some embodiments, thearc length185 of thedistal portion110 may be between about 10 mm to about 15 mm. In some embodiments, thearc length185 of thedistal portion110 may be between about 15 mm to about 20 mm. In some embodiments, thearc length185 of thedistal portion110 may be between about 20 mm to about 25 mm. In some embodiments, thearc length185 of thedistal portion110 may be between about 25 mm to about 30 mm. In some embodiments, thearc length185 of thedistal portion110 may be between about 30 mm to about 35 mm. In some embodiments, thearc length185 of thedistal portion110 may be between about 35 mm to about 50 mm. In some embodiments, thearc length185 of thedistal portion110 may be between about 50 mm to about 75 mm.
• As used herein, the term “arc length”185 of thedistal portion110 of the fixed shape cannula refers to the arc length measured from thetip200 of thedistal portion110 to theinflection point130. The term “radius of curvature”180 of thedistal portion110 of the fixedshape cannula100 refers to the length of theradius182 of the circle/oval181 defined by the curve of the distal portion110 (seeFIG. 19A). In some embodiments, the invention employs a unique sub-tenon insertion methodology, wherein the arc length is designed to be of sufficient length to traverse the Tenon's capsule and portion of the eye which is interposed between the Tenon's capsule entry point and the target (e.g., macula) area.
• In some embodiments, thedistal portion110 of the fixedshape cannula100 has a radius ofcurvature180 between about 9 to 15 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is between about 9 mm to about 10 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is between about 10 mm to about 11 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is between about 11 mm to about 12 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is between about 12 mm to about 13 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is between about 13 mm to about 14 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is between about 14 mm to 15 mm. In some embodiments, thearc length185 of thedistal portion110 and theinflection point130 may also serve to limit the depth of insertion of the fixedshape cannula100 along thesclera235, preventing thetip200 of thedistal portion110 from accidentally damaging posterior ciliary arteries or the optic nerve.
• In some embodiments, thedistal portion110 has a radius ofcurvature180 substantially equal to the radius of curvature of thesclera235 of an adult human eye. Without wishing to limit the present invention to any theory or mechanism, it is believed that having the radius ofcurvature180 of thedistal portion110 be substantially equal to the radius of curvature of thesclera235 of an adult human eye is advantageous because it will ensure that the area that is exposed to the radiation is the outer surface of thesclera235, generally above the macula. In addition, the design permits accurate placement of the RBS and allows a user (e.g., a surgeon) to have the RBS remain fixed in the correct position with minimal effort during the application of the radiation dose. This enables improved geometric accuracy of dose delivery and improved dosing.
• In some embodiments, the radius ofcurvature180 of thedistal portion110 is constant. For example, the radius ofcurvature180 in thedistal portion110 may be a constant 12 mm. In some embodiments, the radius ofcurvature180 of thedistal portion110 is variable. For example, the radius ofcurvature180 in thedistal portion110 may be larger at thedistal region112 and smaller at themiddle region113.
• Without wishing to limit the present invention to any theory or mechanism, it is believed that different and variable radii of curvature may provide for easier and more accurate positioning in special cases, such as that of a myopic eye in which the anteroposterior diameter is greater than the vertical diameter. In this case, it may be advantageous to use a fixedshape cannula100 having adistal portion110 with an overall larger radius ofcurvature180 and specifically having a relatively shorter radius of curvature in thedistal region112 as compared to the radius of curvature in themiddle region113. Similarly, it may be advantageous to use a fixedshape cannula100 having adistal portion110 with an overall smaller radius ofcurvature180 and specifically having a relatively larger radius of curvature in thedistal region112 as compared to the radius of curvature in themiddle region113.
• Thedistal portion110 and theproximal portion120 of the fixedshape cannula100 each have aninner diameter171 andouter diameter172 of the respective vertical cross sections. As shown inFIG. 16, in some embodiments, theinner diameter171 of the vertical cross section of thedistal portion110 is constant (e.g., the inside of the fixedshape cannula100 has a circular cross section). In some embodiments, theinner diameter171 of the vertical cross section of thedistal portion110 is variable (e.g., the inside of the fixedshape cannula100 has an oval cross section). In some embodiments, theouter diameter172 of vertical cross section of thedistal portion110 is constant (e.g., the outside of the fixedshape cannula100 has a circular cross section). In some embodiments, theouter diameter172 of the vertical cross section of thedistal portion110 is variable (e.g., the outside of the fixed shape cannula1000 has an oval cross section).
• In some embodiments, the fixedshape cannula100 has an outer cross sectional shape that is generally circular. In some embodiments, the fixedshape cannula100 has an outer cross sectional shape that is generally round. In some embodiments, the fixedshape cannula100 has an outer cross sectional shape that is oval, rectangular, egg-shaped, or trapezoidal.
• In some embodiments, the fixedshape cannula100 has an internal cross sectional shape that is configured to allow a RBS to be passed through.
• In some embodiments, the fixedshape cannula100 has an internal cross sectional shape that is generally circular. In some embodiments, the fixedshape cannula100 has an outer cross sectional shape that is generally round. In some embodiments, the fixedshape cannula100 has an inner cross sectional shape that is oval, rectangular, egg-shaped, or trapezoidal.
• In some embodiments, the averageouter diameter172 of the vertical cross section of thedistal portion110 is between about 0.1 mm and 0.4 mm. In some embodiments, the averageouter diameter172 of thedistal portion110 is between about 0.4 mm and 10 mm. In some embodiments, the averageouter diameter172 of thedistal portion110 is about 0.9 mm. In some embodiments, the averageouter diameter172 of thedistal portion110 is between about 1.0 mm and 2.0 mm. In some embodiments, the averageouter diameter172 of thedistal portion110 is between about 2.0 mm and 5.0 mm. In some embodiments, the averageouter diameter172 of thedistal portion110 is between about 5.0 mm and 10.0 mm.
• In some embodiments, the averageinner diameter171 of the vertical cross section of thedistal portion110 is between about 0.1 mm and 0.4 mm. In some embodiments, the averageinner diameter171 of thedistal portion110 is between about 0.4 mm and 1.0 mm. In some embodiments, the averageinner diameter171 of thedistal portion110 is about 0.9 mm. In some embodiments, the averageinner diameter171 of thedistal portion110 is between about 10 mm and 2.0 mm. In some embodiments, the averageinner diameter171 of thedistal portion110 is between about 2.0 mm and 5.0 mm. In some embodiments, the averageinner diameter171 of thedistal portion110 is between about 5.0 mm and 100 mm.
• In some embodiments, the averageouter diameter172 of the vertical cross section of thedistal portion110 is about 0.4 mm and the averageinner diameter171 of the vertical cross section of thedistal portion110 is about 0.1 mm (e.g., the wall thickness is about 0.15 mm). In some embodiments, the averageouter diameter172 of the vertical cross section of thedistal portion110 is about 0.7 mm and the averageinner diameter171 of the vertical cross section of thedistal portion110 is about 0.4 mm (e.g., the wall thickness is about 0.15 mm). In some embodiments, the averageouter diameter172 of thedistal portion110 is about 0.9 mm and the averageinner diameter171 of thedistal portion110 is about 0.6 mm (e.g., the wall thickness is about 0.15 mm). In some embodiments, the averageouter diameter172 of thedistal portion110 is about 1.3 mm and the averageinner diameter171 of the distal portion is about 0.8 mm (e.g., the wall thickness is about 0.25 mm). In some embodiments, the averageouter diameter172 of thedistal portion110 is about 1.7 mm and the averageinner diameter171 of thedistal portion110 is about 1.2 mm (e.g., the wall thickness is about 0.25 mm). In some embodiments, the averageouter diameter172 of thedistal portion110 is about 1.8 mm and the averageinner diameter171 of thedistal portion110 is about 1.4 mm (e.g., the wall thickness is about 0.20 mm). In some embodiments, the averageouter diameter172 of thedistal portion110 is about 2.1 mm and the averageinner diameter171 of the distal portion is about 1.6 mm (e.g., the wall thickness is about 0.25 mm).
• In some embodiments, the diameter of thedistal portion110 is between a 12 gauge and 22 gauge wire needle size.
• In some embodiments, the thickness of the distal portion wall (e.g., as measured between theInner diameter171 of thedistal portion110 and theouter diameter172 of the distal portion110) is between about 0.01 mm to about 0.1 mm. In some embodiments, the thickness of the distal portion wall (e.g., as measured between theinner diameter171 of thedistal portion110 and theouter diameter172 of the distal portion110) is between about 0.1 mm to about 0.3 mm. In some embodiments, the thickness of the distal portion wall is between about 0.3 mm to about 1.0 mm. In some embodiments, the thickness of the distal portion wall is between about 1.0 mm to about 5.0 mm. In some embodiments, the thickness of the distal portion wall is constant along the length of thedistal portion110. As shown inFIG. 16B, in some embodiments, the thickness of the distal portion wall is constant about theinner diameter171 andouter diameter172. In some embodiments, the thickness of the distal portion wall varies throughout thedistal portion110, for example along the length of thedistal portion110. As shown inFIGS. 16C and 16D, in some embodiments, the thickness of the distal portion wall varies about theinner diameter171 andouter diameter172.
Proximal Portion Dimensions of the Fixed Shape Cannula
• Theproximal portion120 of the fixedshape cannula100 may also be designed in a number of ways. In some embodiments, theproximal portion120 of the fixedshape cannula100 has anarc length195 between about 10 to 75 mm.
• Thearc length195 of the proximal portion120 (e.g., length of the arc of the proximal portion120) may be of various lengths. In some embodiments, thearc length195 of theproximal portion120 may be between about 10 mm to about 15 mm. In some embodiments, thearc length195 of theproximal portion120 may be between about 15 mm to about 18 mm. In some embodiments, thearc length195 of theproximal portion120 may be between about 18 mm to about 25 mm. In some embodiments, thearc length195 of theproximal portion120 may be between about 25 mm to about 50 mm. In some embodiments, thearc length195 of theproximal portion120 may be between about 50 mm to about 75 mm.
• As used herein, the term “arc length”195 of theproximal portion120 of the fixedshape cannula100 refers to the arc length measured from theinflection point130 to the opposite end of theproximal portion120. The term “radius of curvature”190 of the proximal portion12nof the fixedshape cannula100 refers to the length of theradius192 of the circle/oval191 defined by the curve of the proximal portion120 (seeFIG. 19B).
• In some embodiments, theproximal portion120 of the fixedshape cannula100 has a radius ofcurvature190 between about aninner radius173 of theproximal portion120 of the fixedshape cannula100, for example between 0.1 mm to 1 meter. In some embodiments, the radius ofcurvature190 of theproximal portion120 is constant. In some embodiments, the radius ofcurvature190 of theproximal portion120 is variable.
• Thedistal portion110 and theproximal portion120 of the fixedshape cannula100 each have aninner diameter171 andouter diameter172 of the respective vertical cross sections. As shown inFIG. 16, in some embodiments, theinner diameter171 of the vertical cross section of theproximal portion120 is constant (e.g., the inside of the fixedshape cannula100 has a circular cross section). In some embodiments, theinner diameter171 of the vertical cross section of theproximal portion120 is variable (e.g., the inside of the fixedshape cannula100 has an oval cross section). In some embodiments, theouter diameter172 of vertical cross section of theproximal portion120 is constant (e.g., the outside of the fixedshape cannula100 has a circular cross section). In some embodiments, theouter diameter172 of the vertical cross section of theproximal portion120 is variable (e.g., the outside of the fixedshape cannula100 has an oval cross section).
• In some embodiments, the fixedshape cannula100 has an outer cross sectional shape that is generally round. In some embodiments, the fixedshape cannula100 has an outer cross sectional shape that is oval, rectangular, egg-shaped, or trapezoidal.
• In some embodiments, the fixedshape cannula100 has an internal cross sectional shape that is configured to allow a RBS to be passed through.
• In some embodiments, the fixedshape cannula100 has an internal cross sectional shape that is generally round. In some embodiments, the fixedshape cannula100 has an inner cross sectional shape that is oval, rectangular, egg-shaped, or trapezoidal.
• As shown inFIG. 17,line l₃420 represents the line tangent to the globe of the eye at theinflection point130 and/or limbus.Line l₃420 and line14 (the straight portion of the fixedshape cannula100 or a line parallel to the straight portion of the fixed shape cannula100) form angle θ₁425 (seeFIG. 17). The fixedshape cannula100 may be constructed in many ways, thereforeangle θ₁425 may have various values. In some embodiments, theangle θ₁425 is between greater than about 0 to 180 degrees. In some embodiments, if the fixedshape cannula100 bends through a larger angle, the value of angle θ₁425 is greater.
• In some embodiments,angle θ₁425 is between about 1 to 10 degrees. In some embodiments,angle θ₁425 is between about 10 to 20 degrees. In some embodiments,angle θ₁425 is between about 20 to 30 degrees. In some embodiments,angle θ₁425 is between about 30 to 40 degrees. In some embodiments,angle θ₁425 is between about 40 to 50 degrees. In some embodiments,angle θ₁425 is between about 50 to 60 degrees. In some embodiments,angle θ₁425 is between about 60 to 70 degrees. In some embodiments,angle θ₁425 is between about 70 to 80 degrees. In some embodiments,angle θ₁425 is between about 80 to 90 degrees.
• In some embodiments,angle θ₁425 is between about 90 to 100 degrees. In some embodiments,angle θ₁425 is between about 100 to 110 degrees. In some embodiments,angle θ₁425 is between about 110 to 120 degrees. In some embodiments,angle θ₁425 is between about 120 to 130 degrees. In some embodiments,angle θ₁425 is between about 140 to 150 degrees. In some embodiments,angle θ₁425 is between about 150 to 160 degrees. In some embodiments,angle θ₁425 is between about 160 to 170 degrees. In some embodiments,angle θ₁425 is between about 170 to 180 degrees.
• As shown inFIG. 1,FIG. 3, andFIG. 5, in some embodiments, thedistal portion110 and theproximal portion120 lie in the same plane. In some embodiments, theproximal portion120 is off at an angle from thedistal portion110, for example theproximal portion120 is rotated or twisted with respect to thedistal portion110 such that thedistal portion110 and theproximal portion120 lie in different planes. As shown inFIGS. 18A and 18B, in some embodiments, thedistal portion110 lies inplane P₁431 and theproximal portion120 lies in plane P₂432.Plane P₁431 and plane P₂432 can be defined by their respective normal lines, for example n₁forplane P₁431 and n₂for plane P₂432. Given that thedistal portion110 can be represented as n₁and theproximal portion120 can be represented as n₂, in some embodiments, thedistal portion110 andproximal portion120 can be rotated/twisted with respect to each other between about −90° and +90°.FIG. 18C illustrates several examples of spatial relationships between the proximal portion120 P₂432 and distal portion110P₁431. The spatial relationships between theproximal portion120 anddistal portion110 are not limited to the examples inFIG. 18.
• In some embodiments, the region around theinflection point130 is a gently curving bend such that a radiation source (e.g., a disk-shaped405 RBS, a seed-shaped400 RBS) may be pushed through the fixed shape cannula100 (e.g., from theproximal portion120 to the distal portion110).
• In some embodiments, theinflection point130 of the fixedshape cannula100 extends into a segment of straight fixed shape cannula between thedistal portion110 and theproximal portion120. In some embodiments, the segment is between about 0 to 2 mm. In some embodiments, the segment is between about 2 to 5 mm. In some embodiments, the segment is between about 5 to 7 mm. In some embodiments, the segment is between about 7 to 10 mm. In some embodiments, the segment is more than about 10 mm.
• The present invention also features a fixedshape cannula100 with a fixed shape comprising adistal portion110, aproximal portion120, and aninflection point130 connecting thedistal portion110 and theproximal portion130, wherein thedistal portion110 and/orproximal portion120 has a shape of an arc formed from a connection between a first point and a second point located on anellipsoid450, theellipsoid450 having an x-axis, a y-axis, and a z-axis (seeFIG. 15). Ellipsoids can be defined by the equation below:
• $\frac{x^2}{a^2}+\frac{y^2}{{\mathrm{<figure-callout\; label="b"\; filenames="US20100004499A1-20100107-D00015.png,US20100004499A1-20100107-D00018.png"\; state="\{\{state\}\}">b</figure-callout>}}^2}+\frac{z^2}{c^2}=1$
• In some embodiments, thedistal portion110 has the shape of an arc derived from theellipsoid450 having the x-axis dimension “a,” the y-axis dimension “b,” and the z-axis dimension “c.” In some embodiments, “a” is between about 0 to 1 meter, “b” is between about 0 to 1 meter, and “c” is between about 0 to 1 meter. For example, in some embodiments, “a” is between about 0 to 50 mm, “b” is between about 0 and 50 mm, and “c” is between about 0 and 50 mm.
• In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 1 to 3 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 3 to 5 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 5 to 8 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 8 to 10 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 10 to 12 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 12 to 15 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 15 to 18 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 18 to 20 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” between about 20 to 25 mm. In some embodiments, theellipsoid450 has a dimension “a”, “b”, and/or “c” greater than about 25 mm.
• In some embodiments, theellipsoid450 has dimensions “a” and “b” which are both between about 9 and 15 mm, for example about 12.1 mm. Thisellipsoid450 may be appropriate for designing a fixedshape cannula100 for an emmetropic eye, wherein the eye is generally spherical. In some embodiments, theellipsoid450 has a dimension “a” between about 11 mm and 17 mm, for example about 14 mm, and a dimension “b” between about 9 mm and 15 mm, for example about 12.1 mm. Thisellipsoid450 may be appropriate for designing a fixedshape cannula100 for a myopic eye, wherein the axial length is about 28 mm. In some embodiments, theellipsoid450 has a dimension “a” between about 7 to 13 mm, for example 10 mm, and a dimension “b” between about 9 to 15 mm, for example 12 mm. Thisellipsoid450 may be appropriate for a hyperopic eye, wherein the axial length is about 20 mm.
• In some embodiments, theproximal portion120 has the shape of an arc derived from theellipsoid450 having the x-axis dimension “d,” the y-axis dimension “e,” and the z-axis dimension “f.” In some embodiments, “d” is between about 0 to 1 meter, “e” is between about 0 to 1 meter, and “f” is between about 0 to 1 meter. In some embodiments, “d” is between about 0 to 50 mm, “e” is between about 0 and 50 mm, and “f” is between about 0 and 50 mm.
• In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 1 to 3 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 3 to 5 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 5 to 8 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 8 to 10 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 10 to 12 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 12 to 15 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 15 to 18 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 18 to 20 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 20 to 25 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 25 to 30 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 30 to 40 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” between about 40 to 50 mm. In some embodiments, theellipsoid450 has a dimension “d”, “e”, and/or “f” greater than about 50 mm.
• Theellipsoid450 may be a sphere, wherein “a” is equal to “b”, and “b” is equal to “c”. Theellipsoid450 may be a scalene ellipsoid (e.g., triaxial ellipsoid) wherein “a” is not equal to “b”, “b” is not equal to “c”, and “a” is not equal to “c”.
• In some embodiments, theellipsoid450 is an oblate ellipsoid wherein “a” is equal to “b”, and both “a” and “b” are greater than “c”. In some embodiments, theellipsoid450 is a prolate ellipsoid wherein “a” is equal to “b”, and both “a” and “b” are less than “c”.
• In some embodiments, “a” is about equal to “b” (e.g., for an emmetropic eye). In some embodiments, “a” is not equal to “b” (e.g., for an emmetropic eye). In some embodiments, “b” is about equal to “c”. In some embodiments, “b” is not equal to “c”. In some embodiments, “a” is about equal to “C”. In some embodiments, “a” is not equal to “C”. In some embodiments, “d” is about equal to “e”. In some embodiments, “d” is not equal to “e”. In some embodiments, “e” is about equal to “f”. In some embodiments, “e” is not equal to “f”. In some embodiments, “d” is about equal to “f”. In some embodiments, “d” is not equal to “f”.
• The dimensions of “a,” “b,” and “c” may vary. Table 1 lists several combinations of dimensions. The dimensions of “a,” “b,” and “c” are not limited to those listed in Table 1.

• TABLE 1
  (dimensions in mm +/− 1 mm)

  A	b	c
  12	12	12
  14	12	12
  10	12	12
  12	10	10
  12	10	12
  12	10	14
  12	12	10
  12	12	14
  12	14	10
  12	14	12
  12	14	14
  10	10	10
  10	10	12
  10	10	14
  10	12	10
  10	12	14
  10	14	10
  10	14	12
  10	14	14
  14	10	10
  14	10	12
  14	10	14
  14	12	10
  14	12	14
  14	14	10
  14	14	12
  14	14	14

• The dimensions of “d,” “e,” and “f” may vary. Table 2 lists several combinations of dimensions. The dimensions of “d,” “e,” and “f” are not limited to those listed in Table 2.

• TABLE 2
  (dimensions in mm +/− 1 mm)

  D	e	f

  12	12	12
  12	12	6
  12	12	24
  12	6	24
  12	6	1000
  12	24	1000
  12	0	0
  12	6	6
  12	24	24
  12	1000	1000

• In some embodiments, theellipsoid450 is egg-shaped or a variation thereof.
• The present invention also features a hollow fixedshape cannula100 with a fixed shape comprising adistal portion110 for placement around a portion of a globe of an eye, wherein thedistal portion110 has a radius ofcurvature180 between about 9 to 15 mm and anarc length185 between about 25 to 35 mm. The fixedshape cannula100 comprises aproximal portion120 having a radius ofcurvature190 between about an innercross-sectional radius173 of the fixed shape cannula100 (e.g.,proximal portion120 of fixed shape cannula100) and about 1 meter and aninflection point130, which is where thedistal portion110 and theproximal portion120 connect with each other. In some embodiments, once the distal end (e.g.,tip200, distal region112) of thedistal portion110 is positioned within the vicinity of the target, theproximal portion120 is curved away from thevisual axis220 as to allow a user (e.g., physician) to have direct visual access in the eye.
• In some embodiments, the present invention features a new cannula, said new cannula comprising: (a) a distal segment for placement around a portion of a globe of an eye; wherein the distal segment has a radius of curvature between about 9 to 15 mm and an arc length between about 25 to 35 mm; (b) a proximal segment having a radius of curvature between about an inner cross-sectional radius of said new cannula and about 1 meter; and (c) an inflection point which is where the distal segment and the proximal segments connect with each other; wherein an angle θ₁between a line l₃tangent to the globe of the eye at the inflection point and the proximal segment is between greater than about 0 degrees to about 180 degrees. In some embodiments, the proximal end of the distal segment of said new cannula is tapered such the circumference of the proximal end is larger than the circumference of the distal end of the distal segment. In some embodiments, the distal segment of said new cannula has an arc length which is at least π/4 times the diameter of the globe of the eye under treatment. In some embodiments, the distal segment of said new cannula has sufficient arc length to penetrate the Tenon's capsule of the eye being treated and to extend around the outer diameter of said eye such that the distal end of the distal segment is positioned in the proximity of, and behind, the macula. In some embodiments, there is a means of advancing a RBS which is disposed within said new cannula and wherein said new cannula is for delivering the RBS to the back of the eye, said RBS having a rotationally symmetrical exposure surface capable of more than 1% of the total source radiation energy flux beyond a distance of 1 cm from the exposure surface.
Locator on the Cannula
• In some embodiments, thecannula100 comprises alocator160. In some embodiments, alocator160 is a physical mark (e.g., a visible mark and/or a physical protrusion) disposed on thecannula100. In some embodiments, thelocator160 is for aligning thecannula100 to facilitate the positioning of thedistal portion110 and/ortip200 and/or RBS. In some embodiments, thelocator160 is disposed on thecannula100 such that it will align with the limbus when thecannula100 is in place (see for exampleFIG. 5,FIG. 6B). In some embodiments, theinflection point130 located oncannula100 may serve as alocator160. For example, the user can position theinflection point130 at the limbus as an indication that thetip200 of thecannula100 is approximately at thesclera235 region that corresponds with the target, e.g., the macula.
Materials of Cannula
• In some embodiments, thecannula100 is constructed from a material comprising stainless steel, gold, platinum, titanium, the like, or a combination thereof. In some embodiments, thedistal portion110 and/or theproximal portion120 are constructed from a material comprising surgical stainless steel. In some embodiments, thedistal portion110 and/or theproximal portion120 are constructed from a material comprising other conventional materials such as Teflon, other metals, metal alloys, polyethylene, polypropylene, other conventional plastics, or combinations of the foregoing may also be used. For example, thedistal portion110 may be constructed from a material comprising a plastic. As another example, a part of the tip of thedistal portion110 may be constructed from a material comprising a plastic, and the remainder of thedistal portion110 and theproximal portion120 may be constructed from a material comprising a metal. Without wishing to limit the present invention to any theory or mechanism, it is believed that the plastic has sufficient softness and/or flexibility to minimize the possibility of penetration of thesclera235 or the Tenon'scapsule230 when thecannula100 is inserted into the eye, as described herein. In addition, the length of the plastic portion of thedistal portion110, as well as the specific plastic, are preferably selected so thatdistal portion110 maintains its radius ofcurvature180 when thecannula100 is inserted into the eye.
Handle, Extruding/Advancing Mechanism, Guide Wire
• In some embodiments, thecannula100 is functionally connected with a handle140 (seeFIG. 1,FIG. 4,FIG. 5). Thehandle140 may be connected to theproximal portion120 of thecannula100. In some embodiments, thecannula100 is free of aproximal portion120, and ahandle140 is attached to thedistal portion110 at around the location where theproximal portion120 normally connects to the distal portion110 (e.g., the inflection point130). Without wishing to limit the present invention to any theory or mechanism, it is believed that ahandle140 may provide the user with a better grip on thecannula100 and allow for the user to more easily reach the posterior portion of the eye. In some embodiments, thehandle140 is attached to thecannula100 by a frictional fit and/or conventional fastening means. In some embodiments, thehandle140 comprises a radiation shielding material. In some embodiments, thecannula100 and handle140 are preassembled as one piece. In some embodiments, thecannula100 and handle140 are assembled prior to inserting into the eye. In some embodiments, thecannula100 and handle140 are assembled after inserting thecannula100 into posterior portion of the eye according to the present invention.
• In some embodiments, theproximal portion120 and/or handle140 comprise one or more mechanisms for advancing the RBS (e.g.,disk405, seed-shaped RBS400). Examples of such mechanisms include a slide mechanism, a dial mechanism, athumb ring810, agraduated dial820, aslider830, a fitting, a Toughy-Burst type fitting, the like, or a combination thereof (seeFIG. 4).
• In some embodiments, thecannula100 further comprises a non-wire plunger800 (seeFIG. 4). Non-limiting examples of anon-wire plunger800 include a solid stick, a piston, or a shaft. In some embodiments, thenon-wire plunger800 is constructed from a material comprising a plastic, a metal, a wood, the like, or a combination thereof. In some embodiments, the RBS is extended from and retracted into thecannula100 with thenon-wire plunger800. In some embodiments, thenon-wire plunger800 is air tight. In some embodiments, thenon-wire plunger800 is not air tight. In some embodiments, thecannula100 further comprises a spring.
• In some embodiments, thecannula100 comprises aguide wire350 and/or anon-wire plunger800 which function to advance the RBS. In some embodiments, theguide wire350 and thenon-wire plunger800 are substituted by another mechanism which functions to advance the RBS. In some embodiments, the RBS may be advanced and retracted by hydrostatic pressure employing a fluid (e.g., a saline, an oil, or another type of fluid) using a syringe or other method. In some embodiments, the RBS is advanced and/or retracted by a pneumatic mechanism (e.g., air pressure) and retracted by a vacuum.
• In some embodiments, thenon-wire plunger800 and/or theguide wire350 comprise stainless steel. In some embodiments, thenon-wire plunger800 and/or theguide wire350 are braided. In some embodiments, theguide wire350 comprises a material that is the same material used to encase the RBS (e.g.,disk405, seed-shaped RBS400) such as gold, silver stainless steel, titanium, platinum, the like, or a combination thereof. In some embodiments, theguide wire350 comprises a material that is the same material that the radiation has been deposited into. In some embodiments, the RBS may be advanced and retracted by a Nitinol wire.
Orifice on the Cannula
• In some embodiments, thecannula100 comprises anorifice500 located on an interior side (e.g., bottom) of the distal portion110 (seeFIG. 2). Theorifice500 may be for allowing the radiation to pass through thecannula100 and reach the target. In some embodiments, theorifice500 may be located on thetip200 of thedistal portion110 or on other areas of thedistal portion110. In some embodiments, thedistal portion110 may havemultiple orifices500. In some embodiments, theorifice500 has a round shape (e.g., circular). Theorifice500 may also have alternate shapes such as a square, an oval, a rectangle, an ellipse, or a triangle. In some embodiments, theorifice500 has an area of about 0.01 mm²to about 0.1 mm². In some embodiments, theorifice500 has an area of about 0.1 mm²to about 1.0 mm². In some embodiments, theorifice500 has an area of about 1.0 mm²to about 10.0 mm².
• In some embodiments, the size of theorifice500 is smaller than the size of the RBS (e.g.,disk405, seed-shaped RBS400). In some embodiments, theorifice500 is circular and has a diameter of about 0.1 millimeters. In some embodiments, theorifice500 is circular and has a diameter between about 0.01 millimeters and about 0.1 millimeters. In some embodiments, theorifice500 is circular and has a diameter between about 0.1 millimeters and 1.0 millimeters. In some embodiments, theorifice500 is circular and has a diameter between about 1.0 millimeters and 5.0 millimeters. In some embodiments, theorifice500 is circular and has a diameter between about 5.0 millimeters and 10.0 millimeters.
• In some embodiments, theorifice500 is rectangular. In some embodiments, theorifice500 is rectangular and is about 1.0 mm by 2.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.5 mm by 2.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.5 by 2.0 mm. In some embodiments, theorifice500 is rectangular and is about 0.5 mm by 1.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.5 mm by 1.0 mm. In some embodiments, theorifice500 is rectangular and is about 0.5 mm by 0.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.25 mm by 2.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.25 mm by 2.0 mm. In some embodiments, theorifice500 is rectangular and is about 0.25 mm by 1.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.25 mm by 10 mm. In some embodiments, theorifice500 is rectangular and is about 0.25 mm by 0.5 mm. In some embodiments, theorifice500 is rectangular and is about 0.25 mm by 0.25 mm.
• In some embodiments, thedistal edge520 of theorifice500 is located between about 01 mm and 0.5 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of theorifice500 is located between about 0.5 mm and 1.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of theorifice500 is located between about 1.0 mm and 2.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of theorifice500 is located between about 2.0 mm and 5.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of theorifice500 is located between about 5.0 mm and 10.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of theorifice500 is located between about 10.0 mm and 20.0 mm from thetip200 of thedistal portion110.
Window on the Cannula
• As used herein, the term “radiotransparent” refers to a material that absorbs less than about 10⁻¹or less than about 10⁻²of the radiation flux. For example, awindow510 comprising a radiotransparent material includes awindow510 comprising a material that absorbs 10⁻⁵of the radiation flux.
• In some embodiments, thecannula100 comprises awindow510. In some embodiments, thecannula100 comprises anorifice500 and awindow510, both generally disposed at thedistal portion110 of the cannula100 (seeFIG. 2). In some embodiments, thewindow510 of thecannula100 comprises a material that allows for more radiation transmission than other portions of thecannula100. Awindow510, for example, may comprise a lower density material or comprise a material having a lower atomic number. In some embodiments, thewindow510 may comprise the same material as thecannula100 but have a smaller wall thickness. In some embodiments, thewindow510 comprises a radiotransparent material. In some embodiments, thewindow510 comprises the same material as thecannula100 and has the same wall thickness of thecannula100. In some embodiments, thewindow510 is the area of thecannula100 from where the radiation is emitted.
• In some embodiments, thecannula100 comprises awindow510 located on an interior side (e.g., bottom) of thedistal portion110. Thewindow510 may be used to allow the radiation to pass through thecannula100 and reach a target tissue. In some embodiments, thewindow510 is a portion of thecannula100 having a thickness that is less than the thickness of a cannula wall. In some embodiments, thewindow510 is a portion of thecannula100 having a thickness that is equal to the thickness of a cannula wall. In some embodiments, thewindow510 is a portion of thecannula100 having a thickness that is greater than the thickness of a cannula wall.
• In some embodiments, thedistal portion110 may havemultiple windows510. In some embodiments, thewindow510 has a round shape (e.g., circular). Thewindow510 may also have alternate shapes such as a square, an oval, a rectangle, or a triangle. In some embodiments, thewindow510 has an area of about 0.01 mm²to about 0.1 mm². In some embodiments, thewindow510 has an area of about 0.1 mm²to about 1.0 mm². In some embodiments, thewindow510 has an area of about 1.0 mm²to about 100 mm². In some embodiments, thewindow510 has an area of about 2.5 mm². In some embodiments, thewindow510 has an area of greater than 2.5 mm², for example 50 mm²or 100 mm²
• In some embodiments, thewindow510 is rectangular. In some embodiments, thewindow510 is rectangular and is about 1.0 mm by 2.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.5 mm by 2.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.5 by 2.0 mm. In some embodiments, thewindow510 is rectangular and is about 0.5 by 1.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.5 by 1.0 mm. In some embodiments, thewindow510 is rectangular and is about 0.5 mm by 0.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.25 mm by 2.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.25 mm by 2.0 mm. In some embodiments, thewindow510 is rectangular and is about 0.25 mm by 1.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.25 mm by 10 mm. In some embodiments, thewindow510 is rectangular and is about 0.25 mm by 0.5 mm. In some embodiments, thewindow510 is rectangular and is about 0.25 mm by 0.25 mm. In some embodiments, thewindow510 has an area of greater than 2.5 mm², for example, 50 mm², or 100 mm².
• In some embodiments, the size of thewindow510 is smaller than the size of the RBS (e.g.,disk405, seed-shaped RBS400). In some embodiments, the size of thewindow510 is larger than the size of the RBS. In some embodiments, thewindow510 is elliptical and has axis dimensions of about 0.1 millimeters. In some embodiments, thewindow510 is elliptical and has axis dimensions between about 0.1 millimeters and 1.0 millimeters. In some embodiments, thewindow510 is elliptical and has axes dimensions between about 1.0 millimeters and 5.0 millimeters.
• In some embodiments, thedistal edge520 of thewindow510 is located between about 0.1 mm and 0.5 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of thewindow510 is located between about 0.5 mm and 1.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of thewindow510 is located between about 1.0 mm and 2.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of thewindow510 is located between about 2.0 mm and 5.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of thewindow510 is located between about 5.0 mm and 10.0 mm from thetip200 of thedistal portion110. In some embodiments, thedistal edge520 of thewindow510 is located between about 10.0 mm and 20.0 mm from thetip200 of thedistal portion110.
Radiation Shielding
• In some embodiments, thehandle140 and/or theproximal portion120 and/ordistal portion110 of thecannula100 is constructed from a material that can further shield the user from the RBS (e.g., disk405). In some embodiments, thehandle140 and/or theproximal portion120 comprises a material that is denser than thecannula100. In some embodiments, thehandle140 and/orproximal portion120 comprises a material that is thicker than thecannula100. In some embodiments, thehandle140 and/or theproximal portion120 comprise more layers of material than thecannula100.
• In some embodiments, a part of thedistal portion110 is constructed from a material that can further shield the user and/or the patient from the RBS. For example, the side of thedistal portion110 opposite the side that contacts thesclera235 is constructed from a material that can further shield the patient from the RBS.
• In some embodiments, theproximal portion120 and/or thehandle140 comprises a container that provides radiation shielding, herein referred to as a radiation shielding “pig”900 (seeFIG. 4,FIG. 6). Theradiation shielding pig900 allows for the RBS (e.g., adisk405, a seed-shaped RBS400) to be stored in a retracted position. In some embodiments, theradiation shielding pig900 provides for the storage of the RBS so that the device may be safely handled by the user.
• In some embodiments, theproximal portion120 and/or thehandle140 of thecannula100 has a wall thickness designed to shield the RBS. In some embodiments, theproximal portion120 and/or thehandle140 of thecannula100 comprises stainless steel and has a thickness between about 1 mm to about 2 mm. In some embodiments, theproximal portion120 and/or thehandle140 of thecannula100 comprises stainless steel and has a thickness between about 2 mm to about 3 mm. In some embodiments, theproximal portion120 and/or thehandle140 of thecannula100 comprises stainless steel and has a thickness between about 3 mm to about 4 mm. In some embodiments, theproximal portion120 and/or thehandle140 of the cannula comprises stainless steel and has a thickness between about 4 mm to about 5 mm. In some embodiments, theproximal portion120 and/or thehandle140 of thecannula100 comprises stainless steel and has a thickness between about 5 mm to about 10 mm.
• In some embodiments, theproximal portion120 and/or thehandle140 of thecannula100 comprises a plurality of layers. In some embodiments, theproximal portion120 and/or thehandle140 comprises a plurality of materials. In some embodiments, the plurality of materials comprises a tungsten alloy. Tungsten alloys are well known to those skilled in the art. For example, in some embodiments, the tungsten alloy has a high tungsten content and a low amount of NiFe, as is sometimes used in radiation shielding.
• In some embodiments, shielding a beta isotope in a RBS may be difficult. In some embodiments, a material having a low atomic number (Z) may be used for shielding (e.g., polymethyl methacrylate). In some embodiments, one or more layers of material are used for shielding, wherein an inner layer comprises a material having a low atomic number (e.g., polymethyl methacrylate) and an outer layer comprises lead. In some embodiments, theproximal portion120 and/or thehandle140 and/or theradiation shielding pig900 comprises an inner layer surrounded by an outer layer. In some embodiments, theproximal portion120 and/or thehandle140 and/or theradiation shielding pig900 comprises an inner layer of polymethyl methacrylate (or other material) surrounded by an outer layer of lead (or other material).
• In some embodiments, the inner layer is between about 0.1 mm to 0.25 mm. In some embodiments, the inner layer is between about 0.25 mm to 0.50 mm thick. In some embodiments, the inner layer is between about 0.5 to 1.0 mm thick. In some embodiments, the inner layer is between about 1.0 mm to 1.5 mm thick. In some embodiments, the inner layer is between about 1.5 mm and 2.0 mm thick. In some embodiments, the inner layer is between about 2.0 mm and 5.0 mm thick.
• In some embodiments, the outer layer is between about 0.01 mm to 0110 mm thick. In some embodiments, the outer layer is between about 0.10 mm to 0.15 mm thick. In some embodiments, the outer layer is between about 0.15 to 0.20 mm thick. In some embodiments, the outer layer is between about 0.20 mm to 0.50 mm thick. In some embodiments, the outer layer is between about 0.50 mm and 1.0 mm thick.
• In some embodiments, the inner layer (e.g., polymethyl methacrylate or other material) is about 1.0 mm thick and the outer layer (e.g., lead or other material) is about 0.16 mm thick. In some embodiments, the inner layer (e.g., polymethyl methacrylate or other material) is between about 0.1 mm to 1.0 mm thick and the outer layer (e.g., lead or other material) is between about 0.01 mm to 0.10 mm thick. In some embodiments, the inner layer (e.g., polymethyl methacrylate or other material) is between about 0.1 mm to 1.0 mm thick and the outer layer (e.g., lead or other material) is between about 0.10 mm to 0.20 mm thick. In some embodiments, the inner layer (e.g., polymethyl methacrylate or other material) is between about 1.0 mm to 2.0 mm thick and the outer layer (e.g., lead or other material) is between about 0.15 mm to 0.50 mm thick. In some embodiments, the inner layer (e.g., polymethyl methacrylate or other material) is between about 2.0 mm to 5.0 mm thick and the outer layer (e.g., lead or other material) is between about 0.25 mm to 1.0 mm thick.
• As shown inFIG. 1,FIG. 4, andFIG. 5, in some embodiments, thecannula100 is terminated with ahandle140. In some embodiments, theproximal portion120 further comprises aconnector150. In some embodiments, ahandle140 and/or aradiation shielding pig900 may be fitted to thecannula100 via theconnector150. In some embodiments, theradiation shielding pig900 further comprises a plunger mechanism. In some embodiments, thecannula100 is assembled prior to inserting it into a patient. In some embodiments, thecannula100 is not assembled prior to insertion, for example thecannula100 is assembled after the distal portion1510 is inserted it into a patient.
• In some embodiments, thehandle140 and/or thepig900 is attached to thecannula100 after thecannula100 is inserted via the subtenon approach. Without wishing to limit the present invention to any theory or mechanism, it is believed that attaching thehandle140 and/or thepig900 to thecannula100 after thecannula100 has been inserted is advantageous because thehandle140 and/or thepig900 would not interfere with the placement of thecannula100. Additionally, the placement of thecannula100 may be easier because thehandle140 and/orpig900, which may be bulky, would not interfere with the physical features of the patient.
Tip of Cannula, Indentation Tip
• Thedistal portion110 comprises atip200. In some embodiments, thedistal portion110 comprises atip200 having a rounded shape (seeFIG. 2). In some embodiments, thetip200 is blunt-ended. In some embodiments, thetip200 of thedistal portion110 is open. In some embodiments, thetip200 of thedistal portion110 is closed. In some embodiments, thedistal portion110 has atip200 wherein thetip200 is blunt so as to prevent damage to blood vessels and/or nerves in the periocular tissues and to pass smoothly over thesclera235. In some embodiments, thetip200 of thedistal portion110 further comprises a protuberance (e.g., indentation tip600) projecting from thecannula100 so as to indent thesclera235 and functions as a visual aid to guide thedistal portion110 of thecannula100 to the correct position at the back of the eye (for example, seeFIG. 2). In some embodiments, the indentation of thesclera235 may be observed in the posterior pole of the eye by viewing through the pupil.
• In some embodiments, the protuberance (e.g., indentation tip600) is over the RBS (seeFIG. 2). In some embodiments, the combined thickness of the cannula wall and the indentation tip600 (which may both comprise stainless steel) is about 0.33 mm thick and the RBS thus creates x-rays that deposit more than 1% of the energy radiated by the RBS beyond 1 cm.
• In some embodiments, the protuberance (e.g., indentation tip600) is between about 0.01 mm and 0.10 mm thick. In some embodiments, the protuberance (e.g., indentation tip600) is between about 0.10 mm and 0.20 mm thick. In some embodiments, theindentation tip600 is between about 0.20 mm and 0.33 mm thick. In some embodiments, theindentation tip600 is between about 0.33 and 0.50 mm thick. In some embodiments, theindentation tip600 is between about 0.50 mm and 0.75 mm thick. In some embodiments, theindentation tip600 is between about 0.75 mm and 1.0 mm thick. In some embodiments, theindentation tip600 is between about 1.0 mm and 5.0 mm thick.
Light Source on the Cannula
• In some embodiments, thedistal portion110 comprises atip200 and alight source610 disposed at the tip200 (seeFIG. 2). In some embodiments, thedistal portion110 comprises alight source610 that runs a portion of the length of thedistal portion110. In some embodiments, thecannula100 comprises alight source610 that runs the length of thecannula100. Without wishing to limit the present invention to any theory or mechanism, it is believed that alight source610 that runs the length of thecannula100 may be advantageous because illuminating theentire cannula100 may assist the user (e.g., physician, surgeon) in guiding the placement of thecannula100 and/or observing the physical structures in the area of placement.
• In some embodiments, thelight source610 comprises a light-emitting diode (LED) at thetip200 of thecannula100. The LED light may be seen through transillumination and may help guide the surgeon to the correct positioning of thecannula100. In some embodiments, thelight source610 is directed through thecannula100 by fiberoptics. In some embodiments, alight source610, anindentation tip600, and awindow510 or anorifice500 are coaxial.
• In some embodiments, thelight source610 illuminates the target area. In some embodiments, thelight source610 illuminates a portion of the target area. In some embodiments, thelight source610 illuminates the target area and a non-target area. As used herein, a “target area” is the area receiving about 100% of the intended therapeutic radiation dose. In some embodiments, thecannula100 comprises alight source610 that illuminates more than the targeted radiation zone. Without wishing to limit the present invention to any theory or mechanism, it is believed that a light610 is advantageous because a light610 may create a diffuse illumination through lateral scattering that may be used in lieu of an indirect opthalmoscope light. The light from thelight source610 may extend beyond the lesion to make reference points (e.g., optic nerve, fovea, vessels) visible which may help orient the user (e.g., physician, surgeon).
• In some embodiments, a part of or theentire cannula100 glows. This may allow the user (e.g., physician, surgeon) to observe the insertion of thecannula100 and/or observe the target. In some embodiments, thecannula100 is not illuminated in the area that is to be placed over the target (e.g., everything but the target is illuminated).
Radionuclide Brachytherapy Source
• According to the Federal Code of Regulations, a radionuclide brachytherapy source (RBS) comprises a radionuclide encased in an encapsulation layer. For example, the Federal Code of Regulations defines a radionuclide brachytherapy source as follows: “A radionuclide brachytherapy source is a device that consists of a radionuclide which may be enclosed in a sealed container made of gold, titanium, stainless steel, or platinum and intended for medical purposes to be placed onto a body surface or into a body cavity or tissue as a source of nuclear radiation for therapy.”
• The present invention features a novel radionuclide brachytherapy source (“RBS”). The RBS of the present invention is constructed in a manner that is consistent with the Federal Code of Regulations, but is not limited to the terms mentioned in the Code. For example, the RBS of the present invention may optionally further comprise a substrate (discussed below). Also, for example, in addition to being enclosed by the mentioned “gold, titanium, stainless steel, or platinum”, in some embodiments the radionuclide (isotope) of the present invention may be enclosed by a combination of one or more of “gold, titanium, stainless steel, or platinum” In some embodiments, the radionuclide (isotope) of the present invention may be enclosed by one or more layers of an inert material comprising silver, gold, titanium, stainless steel, platinum, tin, zinc, nickel, copper, other metals, ceramics, or a combination of these.
• The RBS may be constructed in a number of ways, having a variety of designs and/or shapes and/or distributions of radiation. In some embodiments, the RBS comprises asubstrate361, a radioactive isotope362 (e.g., Strontium-90), and an encapsulation.FIG. 14E. In some embodiments, theisotope362 is coated on thesubstrate361, and both thesubstrate361 andisotope362 are further coated with the encapsulation. In some embodiments, theradioactive isotope362 is embedded in thesubstrate361. In some embodiments, theradioactive isotope362 is part of thesubstrate361 matrix. In some embodiments, the encapsulation may be coated onto theisotope362, and optionally, a portion of thesubstrate361. In some embodiments, the encapsulation is coated around theentire substrate361 and theisotope362. In some embodiments, the encapsulation encloses theisotope362. In some embodiments, the encapsulation encloses theentire substrate361 and theisotope362. In some embodiments, theradioactive isotope362 is an independent piece and is sandwiched between the encapsulation and thesubstrate361.
• The RBS is designed to provide a controlled projection of radiation in a rotationally symmetrical (e.g. circularly symmetrical) shape onto the target. In some embodiments, the RBS has an exposure surface that has a rotationally symmetrical shape to provide for the projection of a rotationally symmetrical irradiation onto the target.
• A shape having n sides is considered to have n-fold rotational symmetry if n rotations each of a magnitude of 360°/n produce an identical figure. In some embodiments, shapes described herein as being rotationally symmetrical are shapes having n-fold rotational symmetry, wherein n is a positive integer of 3 or greater.
• In some embodiments, the rotationally symmetrical shape has at least 5-fold rotational symmetry (n=5). In some embodiments, the rotationally symmetrical shape has at least 6-fold rotational symmetry (n=6). In some embodiments, the rotationally symmetrical shape has at least 7-fold rotational symmetry (n=7). In some embodiments, the rotationally symmetrical shape has at least 8-fold rotational symmetry (n=8). In some embodiments, the rotationally symmetrical shape has at least 9-fold rotational symmetry (n=9). In some embodiments, the rotationally symmetrical shape has at least 10-fold rotational symmetry (n=10). In some embodiments the rotationally symmetrical shape has infinite-fold rotational symmetry (n=∞). Examples of rotationally symmetrical shapes such as a circle, a square, an equilateral triangle, a hexagon, an octagon, a six-pointed star, and a twelve-pointed star can be found inFIG. 14F.
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the rotationally symmetrical geometry provides a fast fall off at the target periphery. In some embodiments, the rotationally symmetrical geometry provides a uniform fall off of radiation at the target periphery. In some embodiments, the fast fall off of radiation at the target periphery reduces the volume and/or area irradiated.
Rotationally Symmetrical Exposure Surface Controlled By The Shape of The Substrate
• In some embodiments, a surface on thesubstrate361 is shaped in a manner to provide a controlled projection of radiation in a rotationally symmetrical shape onto the target. For example, in some embodiments, thebottom surface363 of thesubstrate361 is rotationally symmetrical, e.g., circular, hexagonal, octagonal, decagonal, and/or the like. When theradioactive isotope362 is coated onto such rotationally symmetricalbottom surface363 of the substrate362 a rotationally symmetrical exposure surface is created.
• In some embodiments, thesubstrate361 is adisk405, for example adisk405 having aheight406 and a diameter407 (seeFIG. 14). In some embodiments, theheight406 of thedisk405 is between about 0.1 mm and 10 mm. For example, in some embodiments, theheight406 of thedisk405 is between about 0.1 to 0.2 mm. In some embodiments, theheight406 of thedisk405 is between about 0.2 to 2 mm, such as 1.5 mm. In some embodiments, theheight406 of thedisk405 is between about 2 to 5 mm. In some embodiments, theheight406 of thedisk405 is between about 5 to 10 mm. In some embodiments, thediameter407 of thedisk405 is between about 0.1 to 0.5 mm. In some embodiments, thediameter407 of the disk is between about 0.5 to 10 mm. For example, in some embodiments, thediameter407 of thedisk405 is between about 0.5 to 2.5 mm, such as 2 mm. In some embodiments, thediameter407 of thedisk405 is between about 2.5 to 5 mm. In some embodiments, thediameter407 of thedisk405 is between about 5 to 10 mm. In some embodiments, thediameter407 of thedisk405 is between about 10 to 20 mm.
• Thesubstrate361 may be constructed from a variety of materials. For example, in some embodiments thesubstrate361 is constructed from a material comprising, a silver, an aluminum, a stainless steel, tungsten, nickel, tin, zirconium, zinc, copper, a metallic material, a ceramic material, a ceramic matrix, the like, or a combination thereof. In some embodiments, thesubstrate361 functions to shield a portion of the radiation emitted from theisotope362. For example, in some embodiments, thesubstrate361 has thickness such that the radiation from theisotope362 cannot pass through thesubstrate361. In some embodiments, the density times the thickness of thesubstrate361 is between about 0.01 g/cm²to 10 g/cm².
• Thesubstrate361 may be constructed in a variety of shapes. For example, the shape may include but is not limited to a cube, a sphere, a cylinder, a rectangular prism, a triangular prism, a pyramid, a cone, a truncated cone, a hemisphere, an ellipsoid, an irregular shape, the like, or a combination of shapes. As shown inFIG. 14, in some embodiments, thesubstrate361 may have a generally rectangular side cross section. In some embodiments, thesubstrate361 may have a generally triangular or trapezoidal side cross section. In some embodiments, thesubstrate361 may have generally circular/oval side cross section. The side cross section of thesubstrate361 may be a combination of various geometrical and/or irregular shapes.
Rotationally Symmetrical Exposure Surface Controlled by the Shape of the Isotope
• In some embodiments, theisotope362 is coated on theentire substrate361. In some embodiments, theisotope362 is coated or embedded on a portion of the substrate361 (e.g., on thebottom surface363 of the substrate361) in various shapes. For example, the coating of theisotope362 on thesubstrate361 may be in the shape of a rotationally symmetrical shape, e.g., a circle, a hexagon, an octagon, a decagon, or the like. The rotationally symmetrical shape of theisotope362 coating on thebottom surface363 of thesubstrate361 provides for the rotationally symmetrical exposure surface, which results in a controlled projection of radiation in a rotationally symmetrical shape onto the target.
Rotationally Symmetrical Exposure Surface Controlled by the Shape of the Encapsulation
• In some embodiments, the encapsulation is constructed to provide a rotationally symmetrical exposure surface for a controlled projection of radiation having a rotationally symmetrical shape on the target. In some embodiments, the encapsulation has variable thickness so that it shields substantially all of the radiation in some portions and transmits substantially all of the radiation in other portions. For example, in one embodiment, the density times the thickness of the encapsulation is 1 g/cm²at distances greater than 1 mm from the center of the radioactive portion of the source and the density times the thickness of the encapsulation is 0.01 g/cm²at distances less than 1 mm from the center of the radioactive portion of the source. For a Sr-90 source, this encapsulation would block substantially all of the radiation emitted more than 1 mm from the center of the radioactive portion of the source, yet permit substantially all of the radiation emitted within 1 mm of the center of the radioactive portion of the source to pass through. In some embodiments, the thickness of the encapsulation varies between 0.001 g/cm²and 10 g/cm². In some embodiments, rotationally symmetric shapes of the high and low density regions as described above are used.
• The encapsulation may be constructed from a variety of materials, for example from one or more layers of an inert material comprising a steel, a silver, a gold, a titanium, a platinum, another bio-compatible material, the like, or a combination thereof. In some embodiments, the encapsulation is about 0.01 mm thick. In some embodiments, the encapsulation is between about 0.01 to 0.10 mm thick. In some embodiments, the encapsulation is between about 0.10 to 0.50 mm thick. In some embodiments, the encapsulation is between about 0.50 to 1.0 mm thick. In some embodiments, the encapsulation is between about 1.0 to 2.0 mm thick. In some embodiments, the encapsulation is more than about 2.0 mm thick, for example about 3, mm, about 4 mm, or about 5 mm thick. In some embodiments, the encapsulation is more than about 5 mm thick, for example, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm thick.
Rotationally Symmetrical Exposure Surface Controlled By Other Components
• In some embodiments, a radiation-shaper366 can provide a controlled projection of radiation in a rotationally symmetrical shape onto the target. (FIG. 14G). A radiation-shaper366 comprises a radio-opaque portion and a substantially radioactive transparent portion (hereinafter “window364”). In some embodiments, theradiation shaper366 is placed under the RBS. The radiation from the portion of the RBS that overlaps thewindow364 is emitted through thewindow364 toward the target, and the radiation from the portion that does not overlap thewindow364 is blocked by the radio-opaque portion from reaching the target. Thus, awindow364 having a rotationally symmetrical shape will allow for a projection of a rotationally symmetrical irradiation of the target.
• In some embodiments, the window510 (or orifice500) of thecannula100 may be thewindow364 of theradiation shaper366 to provide a controlled projection of radiation in a rotationally symmetrical shape onto the target. For example, in some embodiments, thewindow510 is circular.
• As discussed, a controlled projection of radiation in a rotationally symmetrical shape onto the target allows for a fast fall off at the edge of the target. Also intended to be within the scope of the present invention are the various combinations of arrangements of the components of the RBS and/orcannula100 to produce a controlled projection of radiation in a rotationally symmetrical shape onto a target. Based on the disclosures herein, one of ordinary skill would know how to develop these various combinations to produce a controlled projection of radiation in a rotationally symmetrical shape onto the target allows for a fast fall off at the edge of the target. Fast fall off at the edge of the target may also be enhanced by recessing the RBS in a well having deep radio opaque walls. For example,FIG. 21 shows an RBS recessed in a well with deep walls, where the walls can enhance and even faster fall off of radiation at the target edge.
Isotopes & Radioactivity
• Various isotopes may be employed within the scope of the present invention. Beta emitters such as phosphorus 32 and strontium 90 were previously identified as being useful radioactive isotopes because they are beta emitters that have limited penetration and are easily shielded. In some embodiments, theisotope362 comprises phosphorus 32 (P-32), strontium-90 (Sr-90), ruthenium106 (Ru-106), yttrium 90 (Y-90), the like, or a combination thereof.
• Although they are distinctly different from beta emitters, in some embodiments, the RBS may comprise anisotope362 such as a gamma emitter and/or an alpha emitter. For example, in some embodiments, theisotope362 comprises iodine 125 (I-125), palladium 103 (Pd-103), cesium 131 (Cs-131), cesium 137 (Cs-137), cobalt 60 (co-60), the like, or a combination thereof. In some embodiments, the RBS comprises a combination of various types ofisotopes362. For example, in some embodiments, theisotope362 comprises a combination of Sr-90 and P-32. In some embodiments, theisotope362 comprises a combination of Sr-90 and Y-90.
• To achieve a particular dose rate at the target, the activity of the isotope that is to be used is determined for a given distance between the isotope and the target. For example, if the radiation source is a strontium-yttrium-90 titanate internally contained in a silver-clad matrix forming a disk about 4 mm in diameter and having a height of about 0.06 mm, sealed in titanium that is about 0.8 mm thick on one flat surface of the disk and around the circumference and is about 01 mm thick on the opposite flat surface of the disk (target side of the disk), the target is at a depth of about 1.5 mm (in tissue) and the desired dose rate is about 24 Gy/min at the target, an activity of about 100 mCi may be used. Or, if all aspects of the source are kept the same except that the diameter of the strontium-yittrium-90 titanate internally contained in a silver-clad matrix disk is about 3 mm in diameter, the target is at a depth of about 2.0 mm (in tissue) and the desired dose rate is about 18 Gy/min at the target, an activity of about 150 mCi may be used. Or, if all aspects of the source are kept the same except that the diameter of the strontium-yittrium-90 titanate internally contained in a silver-clad matrix disk is about 3 mm in diameter, the target is at a depth of about 0.5 mm (in tissue) and the desired dose rate is about 15 Gy/min at the target, an activity of about 33 mCi may be used. Or, if all aspects of the source are kept the same except that the diameter of the strontium-yttrium-90 titanate internally contained in a silver-clad matrix disk is about 2 mm in diameter, the target is at a depth of about 5.0 mm (in tissue) and the desired dose rate is about 30 Gy/min at the target, an activity of about 7100 mCi may be used.
• In some embodiments, the isotope has about 5 to 20 mCi, for example, 10 mCi.
• In some embodiments, to achieve a particular dose rate at the target, the radioactivity of theisotope362 that is to be used is determined for a given distance between theisotope362 and the target. For example, if the Sr-90isotope362 is about 5 mm from the target (in tissue) and the desired dose rate is about 20 Gy/min at the target, a Sr-90isotope362 having a radioactivity of about 5,000 mCi may be used. Or, if the P-32isotope362 is about 2 mm from the target and the desired dose rate is about 25 Gy/min at the target, a P-32isotope362 having a radioactivity of about 333 mCi may be used.
• In some embodiments, theisotope362 has an activity of between about 0.5 to 5 mCi. In some embodiments, theisotope362 has an activity of between about 5 to 10 mCi. In some embodiments, theisotope362 has an activity of between about 10 to 50 mCi. In some embodiments, theisotope362 has an activity of between about 50 to 100 mCi. In some embodiments, theisotope362 has an activity of between about 100 to 500 mCi. In some embodiments, theisotope362 has an activity of between about 500 to 1,000 mCi. In some embodiments, the isotope has an activity of between about 1,000 to 5,000 mCi. In some embodiments, the isotope has an activity of between about 5,000 to 10,000 mCi. In some embodiments, theisotope362 has an activity of more than about 10,000 m Ci.
Guide & Memory Wire
• In some embodiments, the RBS (e.g., substrate and/or encapsulation) is attached to theguide wire350 or ribbon that runs through the cannula. In some embodiments, the attachment of thesubstrate361 and/or the encapsulation to theguide wire350 may be achieved using a variety of methods. In some embodiments, thesubstrate361 and/or encapsulation is attached by welding. In some embodiments, thesubstrate361 and/or encapsulation is attached to theguide wire350 by glue. In some embodiments, thesubstrate361 and/or encapsulation is attached to the guide wire350 (or ribbon) by being enveloped in a plastic sleeve having an extension which forms aplastic guide wire350. In some embodiments, this may be achieved using a method such as heat shrink tubing. In some embodiments, thesubstrate361 and/or encapsulation is coated onto theguide wire350 or the ribbon that runs through the cannula.
• In some embodiments, the RBS is in the form of a deployable wafer. In some embodiments, the wafer is in the shape of a cylinder, an ellipse, or the like. In some embodiments, the wafer comprises nickel titanium (NiTi) either doped with or surface coated with a radioisotope that opens up when deployed. In some embodiments, the wafer is coated with a bio-inert material if it is to be left in place for an extended period of time.
• In some embodiments, thememory wire300 comprises the RBS. In some embodiments, thememory wire300 functions like adisk405 or seed-shapedRBS400. The seed-shapedRBS400 may have a spherical or ellipsoidal shape. The shape of the seed-shapedRBS400 is not limited to the aforementioned shapes. In some embodiments, the shape of the seed-shapedRBS400 is determined by dimensions so as to maximize the area and/or the volume that can pass through acannula100 per thecannula100 description. For example, in some embodiments, the RBS is in the shape of a curved cylinder. In some embodiments, the curved cylinder has a rounded distal end and a rounded proximal end so to further accommodate the curvature of thecannula100.
• In some embodiments, the RBS is for inserting into acannula100. In some embodiments, the RBS is designed to traverse a length of thecannula100. In some embodiments, more than one RBS is used to deliver radiation to a target. For example, in some embodiments, twodisks405 may be used inside thecannula100.
• Construction of RBS Wherein More than 1% of the Total Source Radiation Energy Flux Extends Beyond a Distance of 1 cm
• Without wishing to limit the present invention to any theory or mechanism, it is believed that an effective design for a medical device for treating wet age-related macular degeneration should have a radiation dose distribution such that greater than 1% of the total source radiation energy flux (e.g., total radiation energy flux at the source center along the line l_R) is transmitted to greater than or equal to 1 cm distance from the RBS (along the line l_R).
• In some embodiments, the present invention has a RBS that deposits less than about 99% (e.g., 98%, 97%, etc.) of its total source radiation energy flux at distance of 1 cm or less from the RBS.
• In some embodiments, the present invention has a RBS that deposits more than 1% (e.g., 2%, 3%, 4% etc.) of its total source radiation energy flux at distance of 1 cm or more from the RBS. In some embodiments, the present invention has a RBS that deposits between 1% to 15% of its total source radiation energy flux at distance of 1 cm or more from the RBS.
• In some embodiments, the interaction of the isotope radiation (e.g., beta radiation) with the encapsulation (e.g., gold, titanium, stainless steel, platinum) converts some of the beta radiation energy to an emission of bremsstrahlung x-rays. These x-rays may contribute to the entire radiotherapy dose both in the prescribed target area and also penetrate further than beta radiation. Thus such a device as constructed with the aforementioned desirable attributes with a primary beta source will produce a radiation pattern in which 1% or greater of all radiation from the source is absorbed at a distance greater than 1 cm (e.g., the radiation energy flux at a distance of 1 cm away from the center of the target is greater than 1% of the total source radiation energy flux). See Table 3. In some embodiments the present invention features a device wherein the RBS comprises an isotope, wherein the isotope comprises a beta radiation isotope, wherein about 1% of the total source radiation energy flux falls at a distance greater than 1 cm from the center of the target.
• Without wishing to limit the present invention to any theory or mechanism, it is believed that it is desirable to construct the RBS as described in the present invention for ease of manufacturing and so it is inert to the body (due to encasing the RBS in a bio-compatible material). A RBS that is constructed in this manner may produce a radiation pattern comprising beta rays, x-rays, or both beta rays and x-rays, such that greater than 1% of the total source radiation energy flux will extend a distance greater that about 1 cm.
• Table 3 is a listing for non-limiting examples of such Sr-90-constructed radioactive seeds.

• 	TABLE 3
  			Stainless
  	Platinum	Gold	Steel	Titanium

  Thickness (cm)	0.01	0.01	0.033	0.07
  Density	21.45	19.32	8.00	4.54
  Electron Energy	0.6	0.6	0.6	0.6
  Radiative Stopping	0.08662	0.08828	0.02811	0.02297
  Power
  Energy Lost	0.01858	0.017056	0.007421	0.0073
  Fraction of Energy Lost	0.030967	0.028426	0.012368	0.012166
  Mean Photon Energy	0.2	0.2	0.2	0.2
  Attenuation Coefficient	0.137	0.137	0.137	0.137
  for water liquid
  Fraction of photon	0.87197	0.87197	0.87197	0.87197
  energy lost at
  depth >1 cm
  Fraction of initial	0.027002	0.024787	0.010785	0.010609
  electron energy lost
  at depth >1 cm

• In some embodiments, the RBS is in the form of a deployable wafer. In some embodiments, the wafer is in the shape of a cylinder, an ellipse, or the like. In some embodiments, the wafer comprises a nickel titanium (NiTi) substrate, either doped with or surface coated with anisotope362 and then encapsulated, that opens up when deployed. In some embodiments, the wafer is encapsulated with a bio-inert material if it is to be left in place for an extended period of time.
• In some embodiments, the RBS is for inserting into acannula100. In some embodiments, the RBS is designed to traverse a length of thecannula100. In some embodiments, more than one RBS is used to deliver radiation to a target. For example, in some embodiments, tworadioactive disks405 or seed-shapedRBSs400 are inserted into thecannula100.
The Memory Wire
• In some embodiments, thecannula100 of the present invention comprises aguide wire350 inserted within thecannula100, whereby theguide wire350 functions to push a RBS toward thetip200 of thedistal portion110.
• In some embodiments, thecannula100 comprises a memory wire300 (FIG. 2). In some embodiments, thecannula100 comprises aguide wire350 and amemory wire300, wherein theguide wire350 is connected to thememory wire300. In some embodiments, thecannula100 comprises aguide wire350 and amemory wire300, wherein theguide wire350 and thememory wire300 are the same wire. In some embodiments, thememory wire300 may be extended from or retracted into thecannula100 as theguide wire350 is advanced or retracted, respectively.
• In some embodiments, thememory wire300 assumes a shape once it is deployed to thetip200 of thecannula100. In some embodiments, thememory wire300 comprises a material that can take a desirable shape for use in delivering the radiation to a posterior portion of the eye. It will be understood by persons having skill in the art that many shapes of memory wires may be utilized to provide a shape consistent with that required or desired for treatment. In some embodiments, thememory wire300 is in the shape of a spiral, aflat spiral310, a ribbon, the like, or a combination thereof (FIG. 2). In some embodiments, the desirable shape of thememory wire300 for delivering radiation may not allow for thememory wire300 to be inserted into thecannula100. Therefore, in some embodiments, thememory wire300 is capable of being straightened so that it may be inserted into thecannula100. In some embodiments, thememory wire300 may form a shape (e.g., a spiral) when extended from thecannula100. In some embodiments, thememory wire300 having a shape (e.g., a flat spiral310) may be straightened upon being retracted into thecannula100. In some embodiments, thememory wire300 extends from thetip200 of thedistal portion110 of thecannula100.
• In some embodiments, thememory wire300 comprises an alloy of nickel-titanium (NiTi). However, it will be understood by persons having skill in the art that any metal, or alloy, or other material such as spring steel, shape memory nickel-titanium, super-elastic nickel-titanium, plastics and other metals and the like, can be used to create thememory wire300.
• In some embodiments, thememory wire300 comprises the RBS (e.g., substrate261,isotope362 and/or encapsulation). In some embodiments, thememory wire300 has theisotope362 deposited on it and is further encapsulated, thus thememory wire300 comprises the RBS. In some embodiments, thedistal end320 of thememory wire300 comprises the RBS (e.g.,isotope362 and encapsulation), for example thedistal end320 is coated with an isotope and further encapsulated. In some embodiments, thedistal end320 of thememory wire300 comprises the RBS and the remaining portion of thememory wire300 and/or theguide wire350 may act to shield neighboring areas from the radiation. In some embodiments, the RBS and/orisotope362 are applied to thememory wire300 as a thin coating. In some embodiments, the RBS is applied to thememory wire300 as solid pieces.
• In some embodiments, thememory wire300 functions like adisk405 or seed-shapedRBS400. The seed-shapedRBS400 may have a spherical shape, cylindrical shape, or an ellipsoidal shape. The shape of theseed400 is not limited to the aforementioned shapes. In some embodiments, the shape of theseed400 is determined by dimensions so as to maximize the area and/or the volume that can pass through acannula100 per thecannula100 description. For example, in some embodiments, the RBS is in the shape of a curved cylinder. In some embodiments, the curved cylinder has a rounded distal end and a rounded proximal end so to further accommodate the curvature of thecannula100
• In some embodiments, thememory wire300 is advanced toward thetip200 of thecannula100, allowing the memory shape to form. Without wishing to limit the present invention to any theory or mechanism, it is believed that the memory shape is advantageous because when it is formed, it concentrates the RBS in the desired shape. Further, various shapes may be used to achieve a certain concentration of radiation and/or to achieve a certain area of exposure. The shape may be customized to achieve p articular desired results. F or example, a low radiation intensity may be delivered when the wire exposed at the distal end is substantially straight, and a higher radiation intensity may be delivered with the wire exposed at the distal end is coiled up where there is more bundling of the radiation at the area.
• In some embodiments, thememory wire300 is a flat wire similar to a ribbon. In some embodiments, the ribbon may be coated (e.g., with an isotope and encapsulation) on only one edge, and when the ribbon is coiled, the edge that is coated with radiation material will concentrate the RBS, and the other edge not comprising radiation material may act as a shield.
• In some embodiments, the RBS (e.g.,substrate361 and/or encapsulation and isotope362) is attached to theguide wire350. In some embodiments, the attachment of thesubstrate361 and/or the encapsulation to theguide wire350 may be achieved using a variety of methods. In some embodiments, thesubstrate361 and/or encapsulation is attached by welding. In some embodiments, thesubstrate361 and/or encapsulation is attached to theguide wire350 by glue. In some embodiments, thesubstrate361 and/or encapsulation is attached to theguide wire350 by being enveloped in a plastic sleeve having an extension, which forms aplastic guide wire350. In some embodiments, this may be achieved using a method such as heat shrink tubing.
Distal Chamber and Balloon
• In some embodiments, thecannula100 comprises adistal chamber210 disposed at the end of the distal portion110 (seeFIG. 2). Thedistal chamber210 allows amemory wire300 to coil in a protected environment. In some embodiments, thedistal chamber210 is in the shape of a disc. In some embodiments, thedistal chamber210 is in the shape of a two-dimensional tear drop.
• In some embodiments, thedistal chamber210 is rounded at the tip and has a width that is about the same as the width of thecannula100. In some embodiments, thedistal chamber210 is hollow. Thedistal chamber210 allows amemory wire300 or a RBS (e.g.,disk405, seed-shaped RBS400) to be inserted into it. In some embodiments, thememory wire300 curls into a coil in thedistal chamber210. In some embodiments, coiling of thememory wire300 inside thedistal chamber210 concentrates the RBS. Without wishing to limit the present invention to any theory or mechanism, it is believed that concentrating the RBS allows for a faster procedure. Additionally, this may allow for use of a lower activity RBS. In some embodiments, thedistal chamber210 keeps thememory wire300 enclosed in a controlled space, allowing thememory wire300 to coil into thedistal chamber210 and be retracted into thecannula100 without concern of thememory wire300 breaking off or becoming trapped in surrounding structures. In some embodiments, thedistal chamber210 is oriented to lay flat against the back of the eye (e.g., against the sclera).
• In some embodiments, thedistal chamber210 further comprises a protuberance (e.g., distal chamber indentation tip) projecting from thedistal chamber210 so as to indent the sclera and functions to guide thedistal chamber210 to the correct position at the back of the eye. In some embodiments, the distal chamber indentation tip is disposed on the front of thedistal chamber210, the front being the part that has contact with the patient's eye. In some embodiments, the distal chamber indentation trip allows a physician to identify the location of thetip200 of thecannula100 over the target area. In some embodiments, thedistal chamber210 further comprises alight source610.
• In some embodiments, thedistal chamber210 comprises a metal, a plastic, the like, or a combination thereof. In some embodiments, thedistal chamber210 comprises one or more layers of metals and/or alloys (e.g., a gold, a stainless steel). In some embodiments, thedistal chamber210 comprises a material that does not shield the RBS. In some embodiments, thedistal chamber210 comprises anorifice500 and/or awindow510 disposed on the front of thedistal chamber210. In some embodiments, thedistal chamber210 further comprises a radiation shield disposed on the back of thedistal chamber210 and/or a side of thedistal chamber210. Without wishing to limit the present invention to any theory or mechanism, it is believed that adistal chamber210 comprising a radiation shield disposed on the back and/or a side of thedistal chamber210 is advantageous because it would prevent the radiation from being directed to an area other than the target area (e.g., the patient's optic nerve).
• In some embodiments, thecannula100 comprises an expandable tip (e.g., a balloon). In some embodiments, the expandable tip may be expanded using a gas or a liquid, for example balanced salt solution (BSS). In some embodiments, the expandable tip is first expanded, and then the RBS (e.g.,disk405, seed-shaped RBS400) or the radioactive portion of thememory wire300 is deployed. Without wishing to limit the present invention to any theory or mechanism, it is believed that an expandable tip is advantageous because it could act as a guide to position thecannula100 in the correct location. The physician may be able to confirm the position of thecannula100 because the expanded tip would create a convexity in thesclera235. The expandable tip may further comprise a shield for preventing radiation from projecting to an area other than the target area (e.g., the patient's eye).
• In some embodiments, the expandable tip is a balloon. In some embodiments, the balloon in its non-expanded state covers thedistal portion110 of thecannula100 like a sheath.
Doses
• As used herein, the term “lateral” and/or “laterally” refers to in the direction of any line that is perpendicular to line l_R, wherein line l_Ris the line derived from connecting the points l_Sand l_T, wherein l_Sis the point located at the center of the RBS and l_Tis the point located at the center of the target (seeFIG. 10,FIG. 12).
• As used herein, the term “forwardly” refers to in the direction of and/or along line l_Rfrom l_Sthrough l_T, (seeFIG. 10)
• As used herein, the term “substantially uniform” refers to a group of values (e.g., two or more values) wherein each value in the group is no less than about 90% of the highest value in the group. For example, an embodiment wherein the radiation doses at a distance of up to about 1 mm from the center of the target are substantially uniform implies that any radiation dose within the distance of up to about 1 mm away from the center of the target is no less than about 90% of the highest radiation dose within that area (e.g., the total target center radiation dose). For example, if a group of relative radiation doses within a distance of up to about 1 mm away from the center of the target are measured to be 99, 97, 94, 100, 92, 92, and 91, the relative radiation doses are substantially uniform because each value in the group is no less than 90% of the highest value in the group (100).
• As used herein, the term “isodose” (or prescription isodose, or therapeutic isodose) refers to the area directly surrounding the center of the target wherein the radiation dose is substantially uniform (seeFIG. 13).
• Without wishing to limit the present invention to any theory or mechanism, the devices and methods of the present invention are believed to be effective by delivering a substantially uniform dose to the entire target region (e.g., neovascular tissue), or a non-uniform dose, in which the center of the target has dose that is about 2.5× higher than the dose at the boundary regions of the target.
• In some embodiments, a dose of about 16 Gy is delivered to the target. In some embodiments, a dose of about 16 Gy to 20 Gy is delivered to the target. In some embodiments, a dose of about 20 Gy is delivered to the target. In some embodiments, a dose of about 24 Gy is delivered to the target. In some embodiments, a dose of about 20 Gy to 24 Gy is delivered to the target. In some embodiments, a dose of about 30 Gy is delivered to the target. In some embodiments, about 24 Gy to 30 Gy is delivered to the target. In some embodiments, a dose of about 30 Gy to 50 Gy is delivered to the target. In some embodiments, a dose of about 50 Gy to 100 Gy is delivered to the target. In some embodiments, a dose of about 75 Gy is delivered to the target.
Dose Rates
• The medical radiation community believes as medico-legal fact that low dose rate irradiation (e.g., less than about 10 Gy/min) is preferred over high dose rate irradiation because high dose rate irradiation may cause more complications. For example, the scientific publication “Posttreatment Visual Acuity in Patients Treated with Episcleral Plaque Therapy for Choroidal Melanomas: Dose and Dose Rate Effects” (Jones, R., Gore, E., Mieler, W., Murray, K., Gillin, M., Albano, K., Erickson, B., International Journal of Radiation Oncology Biology Physics, Volume 52,Number 4, pp. 989-995, 2002) reported the result “macula dose rates of 111 cGy/h (+/−11.1 cGy/h) were associated with a 50% risk of significant visual loss,” leading them to conclude “higher dose rates to the macula correlated strongly with poorer posttreatment visual outcome.” Furthermore, the American Brachytherapy Society (ABS) issued their recommendations in the scientific publication, “The American Brachytherapy Society Recommendations for Brachytherapy of Uveal Melanomas” (Nag, S., Quivey, J. M., Earle, J. D., Followill, D., Fontanesi, J., and Finger, P. T., International Journal of Radiation Oncology Biology Physics, Volume 56,Number 2, pp. 544-555, 2003) stating “the ABS recommends a minimum tumor I-125 dose of 85 Gy at a dose rate of 0.60 to 1.05 Gy/h using AAPM TG-43 formalism for the calculation of dose.” Thus, the medical standard of care requires low dose rates.
• Despite the teachings away from the use of high dose rates, the inventors of the present invention surprisingly discovered that a high dose rate (i.e., above about 10 Gy/min) may be advantageously used to treat neovascular conditions.
• In some embodiments, the dose rate delivered/measured at the target is greater than 10 Gy/min (e.g., about 15 Gy/min, 20 Gy/min). In some embodiments, the dose rate delivered/measured at the target is between about 10 Gy/min to 15 Gy/min. In some embodiments, the dose rate delivered/measured at the target is between about 15 Gy/min to 20 Gy/min. In some embodiments, the dose rate delivered/measured at the target is between about 20 Gy/min to 30 Gy/min. In some embodiments, the dose rate delivered/measured at the target is between about 30 Gy/min and 40 Gy/min. In some embodiments, the dose rate delivered/measured at the target is between about 40 Gy/min to 50 Gy/min. In some embodiments, the dose rate delivered/measured at the target is between about 50 Gy/min to 75 Gy/min. In some embodiments, the dose rate delivered/measured at the target is between about 75 Gy/min to 100 Gy/min. In some embodiments, the dose rate delivered/measured at the target is greater than about 100 Gy/min.
• In some embodiments, about 16 Gy of radiation is delivered with a dose rate of about 16 G y/min for about 1 minute (as measured at the target). In some embodiments, about 20 Gy of radiation is delivered with a dose rate of about 20 Gy/min for about 1 minute (as measured at the target) In some embodiments, about 25 Gy is delivered with a dose rate of about 12 Gy/min for about 2 minutes (as measured at the target). In some embodiments, about 30 Gy of radiation is delivered with a dose rate of greater than about 10 Gy/min (e.g., 11 Gy/min) for about 3 minutes (as measured at the target). In some embodiments, about 30 Gy of radiation is delivered with a dose rate of about 15 Gy/min to 16 Gy/min for about 2 minutes (as measured at the target). In some embodiments, about 30 Gy of radiation is delivered with a dose rate of about 30 Gy/min for about 1 minute (as measured at the target). In some embodiments, about 40 Gy of radiation is delivered with a dose rate of about 20 Gy/min for about 2 minutes (as measured at the target). In some embodiments, about 40 Gy of radiation is delivered with a dose rate of about 40 Gy/min for about 1 minute (as measured at the target). In some embodiments, about 40 Gy of radiation is delivered with a dose rate of about 50 Gy/min for about 48 seconds (as measured at the target). In some embodiments, about 50 Gy of radiation is delivered with a dose rate of about 25 Gy/min for about 2 minutes (as measured at the target). In some embodiments, about 50 Gy of radiation is delivered with a dose rate of about 75 Gy/min for about 40 seconds (as measured at the target). In some embodiments, a dose rate of about 75 Gy is delivered with a dose rate of about 75 Gy/min for about 1 minute (as measured at the target). In some embodiments, a dose rate of about 75 Gy is delivered with a dose rate of about 25 Gy/min for about 3 minutes (as measured at the target).
• In some embodiments, the target is exposed to the radiation between about 0.01 seconds to about 0.10 seconds. In some embodiments, the target is exposed to the radiation between about 0.10 seconds to about 1.0 second. In some embodiments, the target is exposed to the radiation between about 1.0 second to about 10 seconds. In some embodiments, the target is exposed to the radiation between about 10 seconds to about 15 seconds. In some embodiments, the target is exposed to the radiation between about 15 seconds to 30 seconds. In some embodiments, the target is exposed to the radiation between about 30 seconds to 1 minute. In some embodiments, the target is exposed to the radiation between about 1 minute to about 5 minutes. In some embodiments, the target is exposed to the radiation between about 5 minutes to about 7 minutes. In some embodiments, the target is exposed to the radiation between about 7 minutes to about 10 minutes. In some embodiments, the target is exposed to the radiation between about 10 minutes to about 20 minutes. In some embodiments, the target is exposed to the radiation between about 20 minutes to about 30 minutes. In some embodiments, the target is exposed to the radiation between about 30 minutes to about 1 hour. In some embodiments, the target is exposed to the radiation for more than 1 hour.
Doses, Dose Rates for Tumors
• Without wishing to limit the present invention to any theory or mechanism, it is believed that for treating or managing conditions other than macula degeneration (e.g., tumors), a typical dose is expected to be in the range of about 10 Gy to about 100 Gy, such as 85 Gy. Furthermore, it is believed that to irradiate from the exterior side of the eye where the radiation has to pass through the sclera, the RBS should provide a dose rate of about 0.6 Gy/min to about 100 Gy/min to the target. In some embodiments, for treating conditions other than macula degeneration (e.g., tumors), the RBS provides a dose rate of greater than about 10 Gy/min to about 20 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 20 to 40 Gy/min (e.g., 36 Gy/min) to the target. In some embodiments, the RBS provides a dose rate of greater than about 40 to 60 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 60 to 80 Gy/min to the target. In some embodiments, the RBS provides a dose rate of greater than about 80 to 100 Gy/min to the target. In some embodiments, the dose rate that is chosen by a user (e.g. physicist, physician) to irradiate the tumor depends on one or more characteristics (e.g., height/thickness of the tumor/lesion (e.g., the thickness of the tumor may dictate what dose rate the user uses).
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the exposure time should be between about 15 seconds to about 10 minutes for practical reasons. However, other exposure times may be used. In some embodiments, the target is exposed to the radiation between about 0.01 seconds to about 0.10 seconds. In some embodiments, the target is exposed to the radiation between about 0.10 seconds to about 1.0 second. In some embodiments, the target is exposed to the radiation between about 1.0 second to about 10 seconds. In some embodiments, the target is exposed to the radiation between about 10 seconds to about 15 seconds. In some embodiments, the target is exposed to the radiation between about 15 seconds to 30 seconds. In some embodiments, the target is exposed to the radiation between about 30 seconds to 1 minute. In some embodiments, the target is exposed to the radiation between about 1 to 5 minutes. In some embodiments, the target is exposed to the radiation between about 5 minutes to about 7 minutes. In some embodiments, the target is exposed to the radiation between about 7 minutes to about 10 minutes. In some embodiments, the target is exposed to the radiation between about 10 minutes to about 20 minutes. In some embodiments, the target is exposed to the radiation between about 20 minutes to about 30 minutes. In some embodiments, the target is exposed to the radiation between about 30 minutes to about 1 hour. In some embodiments, the target is exposed to the radiation for more than 1 hour.
Radiation Area, Radiation Profile
• In some embodiments, thecannula100 and/or RBSs of the present invention are designed to treat a small target area with a substantially uniform dose and are also designed so that the radiation dose declines more rapidly as measured laterally from the target as compared to the prior art (seeFIG. 8). The prior art conversely teaches the advantages of a substantially uniform dose over a larger diameter target and with a slower decline in radiation dose (as measured laterally) (e.g., U.S. Pat. No. 7,070,544 B2).
• In some embodiments, the radiation dose rapidly declines as measured laterally from edge of an isodose (e.g., the area directly surrounding the center of the target wherein the radiation dose is substantially uniform) (as shown inFIG. 8).
• FIG. 11 shows a non-limiting example of a radiation dose profile (as measured laterally) of a 1 mm source comprised of Sr-90. In some embodiments, the radiation dose at a distance of about 0.5 mm from the center of the target is about 10% less than the dose on the central axis of the target. In some embodiments, the radiation dose at a distance of about 1.0 mm from the center of the target is about 30% less than the dose on the central axis of the target. In some embodiments, the radiation dose at a distance of about 2.0 mm from the center of the target is about 66% less than the dose on the central axis of the target. In some embodiments, the radiation dose at a distance of about 3.0 mm from the center of the target is about 84% less than the dose on the central axis of the target. In some embodiments, the radiation dose at a distance of about 4.0 mm from the center of the target is about 93% less than the dose on the central axis of the target.
• In some embodiments, the dose on the central axis of the target is the dose delivered at the choroidal neovascular membrane (CNVM). In some embodiments the radiation dose extends away from the target (e.g., choroidal neovascular membrane) in all directions (e.g., laterally, forwardly), wherein the distance that the radiation dose laterally extends in a substantially uniform manner is up to about 0.75 mm away. In some embodiments the radiation dose extends away from the target in all directions (e.g., laterally, forwardly), wherein the distance that the radiation dose laterally extends in a substantially uniform manner is up to about 1.5 mm away. In some embodiments the radiation dose extends away from the target in all directions (e.g., laterally, forwardly), wherein the distance that the radiation dose laterally extends in a substantially uniform manner is up to about 2.5 mm away.
• In some embodiments, the radiation dose at a distance of 2 mm laterally from the center of the target is less than 60% of the radiation dose on the central axis of the target. In some embodiments, the radiation dose at a distance of 3 mm laterally from the center of the target is less than 25% of the radiation dose at the center of the target. In some embodiments, the radiation dose at a distance of 4 mm laterally from the center of the target is less than 10% of the radiation dose at the center of the target. Because the edge of the optic nerve is close to the target, this dose profile provides greater safety for the optic nerve than methods of the prior art.
• In some embodiments, the radiation dose is substantially uniform within a distance of up to about 1.0 mm (as measured laterally) from the center of the target. In some embodiments, the radiation dose declines such that at a distance of about 2.0 mm (as measured laterally) from the center of the target, the radiation dose is less than about 25% of the radiation dose at the center of the target. In some embodiments, the radiation dose declines such that at a distance of about 2.5 mm (as measured laterally) from the center of the target, the radiation dose is less than about 10% of the radiation dose at the center of the target.
• In some embodiments, the radiation dose is substantially uniform within a distance of up to about 6.0 mm (as measured laterally) from the center of the target. In some embodiments, the radiation dose declines such that at a distance of about 12.0 mm (as measured laterally) from the center of the target, the radiation dose is less than about 25% of the radiation dose at the center of the target. In some embodiments, the radiation dose declines such that at a distance of about 15.0 mm (as measured laterally) from the center of the target, the radiation dose is less than about 10% of the radiation dose at the center of the target.
• In some embodiments, the radiation dose is substantially uniform within a distance of up to about 10.0 mm (as measured laterally) from the center of the target. In some embodiments, the radiation dose declines such that at a distance of about 20.0 mm (as measured laterally) from the center of the target, the radiation dose is less than about 25% of the radiation dose at the center of the target. In some embodiments, the radiation dose declines such that at a distance of about 25.0 mm (as measured laterally) from the center of the target, the radiation dose is less than about 10% of the radiation dose at the center of the target.
• In some embodiments, the radiation dose at the center of the target (e.g., radiation dose at the center of the choroidal neovascular membrane) does not extend laterally to the entire macula (a diameter of about 1.5 mm to 6.0 mm). In some embodiments, the devices of the present invention may also treat a larger area and still have a faster radiation dose fall off as compared to devices of the prior art.
Benefit of Short Delivery Time
• Without wishing to limit the present invention to any theory or mechanism, it is believed that faster delivery time of radiation is advantageous because it allows the physician to hold the instrument in the desired location with minimal fatigue, and it minimizes the amount of time that the patient is subjected to the procedure. Lower dose rates and longer delivery times may cause fatigue in the physician, possibly leading to the accidental movement of the cannula from the target. Furthermore, longer delivery times increase the chance of any movements of the physician's hand or the patient's eye or head (when local anesthesia is employed, the patient is awake during the procedure).
• Another benefit of a faster delivery time is the ability to employ short-term local anesthetics (e.g., lidocaine) and/or systemic induction drugs or sedatives (e.g., methohexital sodium, midazolam). Use of short-term anesthetics result in a quicker recovery of function (e.g., motility, vision) after the procedure Shorter acting anesthetics cause shorter-lasting respiratory depression in case of accidental central nervous system injection.
Shutter System
• In some embodiments, thecannula100 comprises a shutter system disposed near or at thetip200 of thecannula100. The shutter system may be similar to the shutter system of a camera. In some embodiments, a shutter system is used to deliver up to about a 200,000 Gy/min dose rate in a time frame of about 0.01 second. Without wishing to limit the present invention to any theory or mechanism, it is believed that a shutter system would be advantageous because it would allow for such a short exposure time that the radiation dose can be delivered to the target without worry of a hand, eye, or head movement moving thecannula100 away from the target.
• Alternatively to a shutter system, in some embodiments, a high dose rate can be delivered in a short amount of time using a mechanism of a very fast after-loaded system, wherein the RBS is quickly moved to the treatment position for a quick dwell time and the retracted away from the treatment position.
• The present invention is illustrated herein by example, and various modifications may be made by a person of ordinary skill in the art. For example, although thecannulae100 of the present invention have been described above in connection with the preferred sub-Tenon radiation delivery generally above the macula, thecannulae100 may be used to deliver radiation directly on the outer surface of thesclera235, below the Tenon'scapsule230, and generally above portions of the retina other than the macula. Moreover, in some embodiments, the devices (e.g., cannulae100) of the present invention may be used to deliver radiation from below the conjunctiva and above the Tenon'scapsule230. In some embodiments, the devices may be used to deliver radiation to the anterior half of the eye. In some embodiments, the devices may be used to deliver radiation from above the conjunctiva. As another example, the arc length and/or radius of curvature of the distal portions of the cannula may be modified to deliver radiation within the Tenon'scapsule230 or thesclera235, generally above the macula or other portions of the retina, if desired.
Additional Rationale of Device and Methods
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the methods of the present invention, which feature a posterior radiation approach, are superior to methods that employ either a pre-retinal approach or an intravitreal radiation approach using an intravitreal device910 (seeFIG. 9, see U.S. Pat. No. 7,223,225 B2) for several reasons.
• For example, the pre-retinal approach (e.g., irradiating the target area by directing the radiation from the anterior side of the retina back toward the target) irradiates the anterior structures of the eye (e.g., cornea, iris, ciliary body, lens) and has the potential to irradiate the tissues deeper than the lesion, such as the periorbital fat, bone, and the brain. The intravitreal radiation approach (e.g., irradiating the target area by directing the radiation from within the vitreous chamber from the anterior side of the eye back towards the target) also has the potential to irradiate the tissues deeper than the lesion (e.g., periorbital fat, bone, brain) and also, in a forward direction, the lens, ciliary body and cornea. It is believed that the methods of the present invention will spare the patient from receiving ionizing radiation in the tissues behind the eye and deeper than the eye. According to the present invention, the radiation is directed forward (e.g., the radiation is directed from the posterior side of the eye forward to the target) and is shielded in the back, and therefore excess radiation would enter primarily into the vitreous gel and avoid the surrounding tissues (e.g., fat, bone, brain).
• Keeping thecannula100 in a fixed location and at a distance from the target during the treatment reduces the likelihood of errors and increases the predictability of dose delivery. Conversely, approaching the radiation treatment by inserting a device into the vitreous chamber (e.g., an intravitreal approach) requires a physician to hold the device in a fixed location and a fixed distance from the target in the spacious vitreous chamber (seeFIG. 9). It may be difficult for the physician to hold precisely that position for any length of time. Furthermore, it is generally not possible for the physician/surgeon to know the exact distance between the probe and the retina; he/she can only estimate the distance. By approaching the treatment from behind the eye, the physician is able to hold the device at a precise fixed distance from the target because the intervening structures (e.g., the sclera235) support the device, help to hold thecannula100 in place, and act as a fixed spacer. This improves both the geometric accuracy and dose precision. As shown in Table 4, the radiation dose varies greatly depending on the depth (e.g., distance away from the source as measured along line l_R). For example, if the distance between the RBS (e.g., probe) is moved from 0.1 mm away from the target to 0.5 mm, the dose may decrease by about 25 to 50%.

• TABLE 4
  Depth (mm)
  (Distance away from	Relative Radiation Dose

  source, as measured

  Sr-09 Source

  P-32 Source

  along line lR)	1.5 mm size	3.0 mm size	3.0 mm size

  0.1	100	100	100
  0.5	50.02	75.00	74.64
  1.0	20.85	46.68	44.76
  2.0	6.05	19.92	15.02
  3.0	2.37	8.12	5.00
  4.0	0.99	3.56	1.51
  5.0	0.43	1.56	0.37
  6.0	0.18	0.66	0.08
  7.0	0.07	0.26	0.02
  8.0	0.02	0.07	0.01

• The posterior approach is also easier and faster than the intravitreal approach. The posterior approach is less invasive than the intravitreal approach, and avoids the side effects of intravitreal procedures (e.g., vitrectomy, intravitreal steroid injections or VEGF injections) which are often cataractogenic, as well as the possibility of mechanical trauma to the retina or intraocular infection. The posterior approach is safer for the patient.
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the devices of the present invention are advantageous over other posterior radiation devices of the prior art because the devices of the present invention are simpler mechanically and less prone to malfunction. In some embodiments, the devices of the present invention are only used one time.
• Without wishing to limit the present invention to any theory or mechanism, it is believed that the unique radiation profile of the present invention is advantageous over the prior art. As discussed previously and as shown inFIG. 8, the devices and methods of the present invention, which suitably employ the rotationally symmetrical surface concept described above, provide for a more sharply demarcated dose radiation profile from the edge of a substantially uniform dose region. Other posterior devices do not provide this unique radiation profile. The devices and methods of the present invention are advantageous because they will deliver a therapeutic dose of radiation to the target (e.g., neovascular growths affecting the central macula structures) while allowing for the radiation dose to fall off more quickly than the prior art, which helps prevent exposure of the optic nerve and/or the lens to radiation. Further, a faster fall off of the lateral radiation dose minimizes the risk and the extent of radiation retinopathy, retinitis, vasculitis, arterial and/or venous thrombosis, optic neuropathy and possibly hyatrogenic neoplasias.
• In some embodiments, thecannula100 is after-loaded with radiation. In some embodiments, the RBS is pushed forward to anorifice500 or awindow510 at thetip200 of thecannula100. In some embodiments, the devices of the present invention do not comprise a removable shield or a shutter.
• The present methods of treatment may be used alone or in combination with a pharmaceutical, e.g., for treating Wet Age-Related Macular Degeneration. Non-limiting examples of pharmaceuticals that may be used in combination with the present invention includes a radiation sensitizer an anti-VEGF (vascular endothelial growth factor) drug such as Lucentis™ or Avastin™, and/or other synergistic drugs such as steroids, vascular disrupting agent therapies, and other anti-angiogenic therapies both pharmacologic and device-based.
Example 1Surgical Technique
• The following example describes a surgical procedure for use of the cannulae of the present invention. The eye is anesthetized with a peribulbar or retrobulbar injection of a short acting anesthetic (e.g., Lydocaine). A button hole incision in the superotemporal conjunctiva is preformed followed by a button hole incision of theunderlying Tenon capsule230.
• If acannula100 comprising adistal chamber210 is used, a small conjunctive peritomy (as large as the diameter of the distal chamber) is performed at the superotemporal quadrant. A Tenon incision of the same size is then performed in the same area to access the subtenon space.
• Balanced salt solution and/or lydocaine is then injected in the subtenon space to separate gently theTenon capsule230 from thesclera235.
• Thecannula100 is then inserted in the subtenon space and slid back until thetip200 is at the posterior pole of the eye. In some embodiments, thecannula100 comprises alocator160. Thelocator160 indicates when the correct position has been reached. In some embodiments, thecannula100 comprises a protuberance to act as anindentation tip600. The surgeon may then observe theindentation tip600 or simply the indentation in the retina caused by thecannula100 using indirect opthalmoscopy through the dialated pupil. If the indentation indicates the radiotherapy is not exactly on the underlying the choroidal neovascular membrane, the surgeon may adjust the position of thecannula100 while directly visualizing the posterior pole with or without the aid of an operating microscope/opthalmoscope (this adjustment is the “fine positioning” adjustment). In some embodiments, the surgeon adjusts the position of the cannula while the patient's eye is in a primary gaze position. In some embodiments, the surgeon adjusts the position of the cannula while the patient's eye is in any one of the following position: elevated, depressed, adducted, elevated and adducted, elevated and abducted, depressed and adducted, and depressed and abducted.
• in some embodiments, thecannula100 comprises apilot light source610 near thetip210 of thecannula100 or along the length of thecannula100. The light may be seen through transillumination and may help guide the surgeon to the correct positioning of thecannula100. In some embodiments, thelight source610 is directed through thecannula100 by fiberoptics or by placement of a LED.
• In some embodiments, once thecannula100 is in place, the RBS (e.g.,disk405, seed-shaped RBS400) is then pushed to thedistal portion110 of thecannula100. The radiation escapes thecannula100 through anorifice500 or awindow510 located on the side/bottom of thecannula100 adjacent to thesclera235. In some embodiments, thedistal end320 of thememory wire300 comprises the RBS, and the radioactive portion of thememory wire300 is pushed to thetip200 of thedistal portion110 of thecannula100. In some embodiments, thememory wire300 is pushed into thedistal chamber210 or into a balloon.
• The RBS (e.g., disk405) is left in place for the desired length of time. When the planned treatment time has elapsed, the RBS (e.g.,disk405, memory wire300) is then retracted to its original position. Thecannula100 may then be removed from the subtenon space. The conjunctiva may then be simply reapproximated or closed with bipolar cautery or with one, two, or more interrupted reabsorbable sutures.
• The button hole cunjunctiva/tenon incision has several advantages over a true conjunctiva/Tenon incision. It is less invasive, faster, easier to close, more likely to be amenable to simple reapproximation, less likely to require sutures, and causes less conjunctiva scarring (which may be important if the patient has had or will have glaucoma surgery).
Example 2Fast Radiation Fall Off at the Edge of the Target
• After the cannula is placed into position, an RBS is introduced to the sclera region on the eye ball that corresponds with the target (e.g., macula lesion) on the retina. Radionuclide of the RBS is Sr-90, and the RBS has a rotationally symmetrical exposure surface (e.g., circular) (seeFIG. 14E). The exposure surface of the RBS has a diameter of about 3 mm. The target is 3 mm in diameter and is about 1.5 mm away from the exposure surface of the RBS.
• As shown inFIG. 22, a target that is 1.5 mm away from the exposure surface has a radiation profile where the intensity of the radiation at the edge falls off significantly, i.e., there is a fast fall of at the target edge. When a shielding (deep wall, seeFIG. 21) is employed, the radiation fall off at the edge is faster compared to when there is no shielding.
• In this example, the ratio of the target diameter to the exposure surface diameter is about 1:1.
• Various modifications of the invention, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. Each reference cited in the present application is incorporated herein by reference in its entirety.
• Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.

Claims (46)

1. A method of irradiating a target of an eye in a patient, said method comprising:

(a) inserting a cannula into a potential space under a Tenon's capsule of the eye of the patient, the cannula configured to have a radionuclide brachytherapy source (RBS) at a treatment position,

(b) observing through a pupil the position of the treatment position in a posterior pole of the eye,

(c) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target,

(d) irradiating the target with the RBS.

2. The method ofclaim 1, wherein the Tenon's capsule guides insertion of the cannula and provides positioning support for the cannula.

3. The method ofclaim 1, wherein the target is located on a vitreous side of the eye.

4. The method ofclaim 1, wherein the RBS is loaded into the cannula before the cannula is inserted.

5. The method ofclaim 1, wherein the RBS is loaded into the cannula after the cannula is inserted.

6. The method ofclaim 1, wherein the cannula is a fixed shape cannula.

7. The method ofclaim 1, wherein the cannula is a flexible cannula, including an endoscope.

8. The method ofclaim 1, wherein the target is a lesion associated with a retina of the eye.

9. The method ofclaim 8, wherein the lesion is a neovascular lesion.

10. The method ofclaim 8, wherein the lesion is a benign growth or a malignant growth.

11. The method ofclaim 1, wherein the RBS provides a dose rate of between about 0.1 to 1 Gy/min to the target.

12. The method ofclaim 1, wherein the RBS provides a dose rate of between about 1 to 10 Gy/min to the target.

13. The method ofclaim 1, wherein the RBS provides a dose rate of between about 10 to 20 Gy/min to the target.

14. The method ofclaim 1, wherein the RBS provides a dose rate of between about 20 to 30 Gy/min to the target.

15. The method ofclaim 1, wherein the RBS provides a dose rate of between about 30 to 40 Gy/min to the target.

16. The method ofclaim 1, wherein the RBS provides a dose rate of between about 40 to 50 Gy/min to the target.

17. The method ofclaim 1, wherein the RBS provides a dose rate of between about 50 to 75 Gy/min to the target.

18. The method ofclaim 1, wherein the RBS provides a dose rate of between about 75 to 100 Gy/min to the target.

19. The method ofclaim 1, wherein the cannula is inserted at a limbus of the eye.

20. The method ofclaim 1, wherein the cannula is inserted at a point posterior to a limbus of the eye.

21. The method ofclaim 1, wherein the cannula is inserted at a point between a limbus and a fornix of the eye.

22. A method of irradiating a target of an eye in a patient, said method comprising:

(a) inserting a cannula into a potential space under a Tenon's capsule of the eye of the patient;

(b) placing a distal portion of the cannula on or near a sclera behind the target;

(c) observing through a pupil the position of the distal portion of the cannula in a posterior pole of the eye;

(d) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the distal portion of the cannula, the fine positioning is achieved when a treatment position of the distal portion is positioned over a target,

(e) advancing a RBS through the cannula to the treatment position of the distal portion via a means for advancing a RBS; and

(f) exposing the target to the RBS.

23. The method ofclaim 22, wherein the cannula is inserted at a limbus of the eye.

24. The method ofclaim 22, wherein the cannula is inserted at a point posterior to a limbus of the eye.

25. The method ofclaim 22, wherein the cannula is inserted at a point between a limbus and a fornix of the eye.

26. The method ofclaim 22, wherein the distal portion of the cannula is designed for placement around a portion of a globe of an eye; wherein the distal portion has a radius of curvature between about 9 to 15 mm and an arc length between about 25 to 35 mm;

the cannula further comprising a proximal portion having a radius of curvature between about an inner cross-sectional radius of the cannula and about 1 meter; and an inflection point which is where the distal portion and the proximal portions connect with each other;

wherein an angle θ₁between a line l₃tangent to the globe of the eye at the inflection point and the proximal portion is between greater than about 0 degrees to about 180 degrees.

27. The method ofclaim 1, wherein the cannula is tapered, having a larger circumferential area at a portion of the cannula that remains in the Tenon's capsule upon insertion.

28. A method of delivering a radiation to an eye, said method comprising irradiating a target on a vitreous side of the eye from an outer surface of a sclera, wherein the target receives a dose rate of greater than about 10 Gy/min, the method further comprises:

(a) observing through a pupil the position of the treatment position in a posterior pole of the eye,

(b) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target.

29. The method ofclaim 28, wherein a hollow cannula is used to deliver a RBS to the sclera region corresponding to the target, the cannula is inserted between a Tenon's capsule and a sclera of the eye; the cannula having a fixed shape, said cannula comprises a distal portion for placement on a portion of the globe of the eye and a proximal portion connected to the distal portion via an inflection point.

30. The method ofclaim 28, wherein the RBS provides a dose rate of greater than about 11 Gy/min to the target.

31. The method ofclaim 28, wherein the RBS provides a dose rate of greater than about 12 Gy/min to the target.

32. The method ofclaim 28, wherein the RBS provides a dose rate of greater than about 13 Gy/min to the target.

33. The method ofclaim 28, wherein the RBS provides a dose rate of greater than about 14 Gy/min to the target.

34. The method ofclaim 28, wherein the RBS provides a dose rate of greater than about 15 Gy/min to the target.

35. The method ofclaim 28, wherein the RBS provides a dose rate between about 15 to 30 Gy/min to the target.

36. The method ofclaim 28, wherein the RBS provides a dose rate between about 30 to 60 Gy/min to the target.

37. The method ofclaim 28, wherein the RBS provides a dose rate between about 60 to 100 Gy/min to the target.

38. The method ofclaim 28, wherein the target is a neovascular tissue.

39. The method ofclaim 28, wherein the target is a macula.

40. The method ofclaim 28, wherein the target is a benign growth or a malignant growth.

41. A method of irradiating a target associated with a retina of an eye in a patient, said method comprising placing a radionuclide brachytherapy source (“RBS”) at or near a sclera portion of the eye that corresponds with the target, the RBS irradiates the target through the sclera, wherein more than 1% of a radiation from the RBS is deposited on a tissue at or beyond a distance of 1 cm from the RBS, the method further comprises:

(a) observing through a pupil the position of the treatment position in a posterior pole of the eye,

(b) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target.

42. The method ofclaim 41, wherein about 1% to about 15% of the radiation from the RBS is deposited on a tissue at or beyond a distance of 1 cm from the RBS.

43. The method ofclaim 41, wherein about less than 99% of the radiation from the RBS is deposited on a tissue at a distance less than 1 cm from the RBS.

44. A method of irradiating a target of an eye in a patient, said method comprising inserting a cannula between a Tenon's capsule and a sclera of the eye of the patient,

the cannula has a radionuclide brachytherapy source (“RBS”) at a distal end, wherein the RBS is positioned over the sclera portion that corresponds with the target, the RBS irradiates the target through the sclera;

wherein the target receives a dose rate of greater than about 10 Gy/min;

wherein the cannula is a fixed shape cannula; and

wherein the RBS is loaded into the cannula after the cannula is inserted;

the method further comprising:

(a) observing through a pupil the position of a treatment position in a posterior pole of the eye,

(b) adjusting the cannula that is under the Tenon's capsule to achieve fine positioning of the treatment position, the fine positioning is achieved when the treatment position is over a target.

45. The method ofclaim 44, wherein the target is a lesion associated with a retina of the eye.

46. The method ofclaim 45, wherein the lesion is a neovascular lesion.

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