US20030192557A1 - Systems and methods for locating and defining a target location within a human body - Google Patents

Abstract

Systems and methods for locating and defining a target location within a human body. The system can include at least one marker, a probe, and a detector for use in locating the markers by providing information to a surgeon that is representative of changes in proximity between the probe and the marker. The marker can have various detection characteristics, e.g., gamma radiation, that are detectable by an associated probe and detector. The tissue volume is removed by manipulating a cutting tool based on the proximity information provided by the detector, which can be used by the surgeon to define the boundary of the tissue volume. The systems and methods of the invention are particularly useful in locating and then removing a tissue volume or other target location from amorphous, pliable tissue (e.g., breast tissue) or other body parts.

Description

TECHNICAL FIELD
• Several aspects of the present invention relate to systems and methods for locating a target tissue within a human body with wireless markers. Other aspects of the invention relate to wireless markers, instruments, user interfaces, and methods for using such systems in treating or monitoring a target location.[0001]
BACKGROUND
• Many medical procedures require monitoring or treating an internal tissue mass or other body part within a human body. In such applications, medical procedures must accurately locate a small target location within a soft tissue region, an organ, a bone structure, or another body part (e.g., colon, vascular system, etc.). The small target location can be a lesion, polyp, tumor, or another area of interest for monitoring or treating a patient. One particular application involving the surgical treatment of cancer is particularly challenging because physicians often need to treat small, non-palpable lesions that cannot be observed. This problem is compounded in soft tissue applications because the soft tissue is mobile and can move with respect to a reference point on the patient. In the case of breast cancer, for example, the location of a non-palpable lesion in the breast is identified at a preoperative stage using an imaging system. The actual surgical procedure, however, occurs in an operating room at a subsequent point in time, and the patient is typically in a different position during the surgical procedure than during the preoperative imaging stage. The breast and the lesion may accordingly be in a different location relative to a reference point on the patient during the surgical procedure than the imaging stage. The physician, therefore, generally estimates the location of lesion during surgery.[0002]
• One problem with treating non-palpable lesions in soft tissues is that the physicians may incorrectly estimate the location of the lesions. As a result, the physician may not remove all of the lesion, which is not desirable because some of the lesion will accordingly remain in the soft tissue. Another result is that the physicians may remove a significant amount of tissue proximate to the lesion, which can cause undesirable collateral damage to healthy tissue. Therefore, it would be desirable to know the precise location of the lesion or other type of target location during the surgical procedure.[0003]
• A current technique for performing an excisional biopsy of a non-palpable breast lesion that has been identified by mammogram or other method involves placement of a needle or guide wire (e.g., a “Kopanz wire”), with or without blue dye, to guide the surgeon to the lesion. The tip of the needle is generally placed directly in or as close as possible to the lesion. When larger or more complex lesions are encountered, two or more guide wires are sometimes placed at each edge of the lesion. The entry point of the needle through the skin of the breast is usually several centimeters from the lesion due to the logistics of needle placement. The surgeon does not cut along the shaft of the needle from the skin because the distance is too great. Instead, the surgeon must estimate where in the breast the lesion is located by making reference to the location of the needle.[0004]
• This technique is not optimal because it can be difficult to properly define the margins of the tissue that is to be removed, both during and after insertion of the needle(s), in tissue that is amorphous and pliable (e.g., breast tissue). Also, it is often difficult for the surgeon to detect the exact depth of the lesion based on the placement of the needles. For these reasons it is not uncommon that the biopsied tissue does not contain the mammographically positive specimen. In other cases, as a result of the difficulty of estimating the proper location of the boundaries of the volume of tissue to be removed, the lesion ends up being eccentrically positioned within the volume of tissue excised. This calls into question the adequacy of the margin of normal tissue surrounding the lesion. In still other cases, more normal tissue is removed than is required, which is disadvantageous in this era of tissue-conserving therapies.[0005]
• In other fields of surgery it is known to target portions of a human body using various devices, and then refer to such devices in connection with the removal or treatment of such portions. For example, U.S. Pat. No. 5,630,431 to Taylor (the “'431 patent”) describes a surgical manipulator that is controlled, in part, by information received from beacons that are positioned proximate to a region of a human body to be treated. As another example, U.S. Pat. No. 5,397,329 to Allen (the “'329 patent”) describes fiducial implants for a human body that are detectable by an imaging system. The fiducial implants are implanted beneath the skin and are spaced sufficiently from one another to define a plane that is detectable by the imaging system and is used in connection with creation of images of a body portion of interest. These images are then used, for instance, in eliminating a tumor by laser beam.[0006]
• Unfortunately, the devices described in the '431 and '329 patents are vastly more complex, and hence expensive, than is appropriate for many surgical procedures. This problem is particularly disadvantageous with the emphasis on containing costs in managed health care. Furthermore, due to the amorphous, pliable nature of certain tissue, the systems of the '431 and '329 patents cannot be used effectively. Systems of the type described in the '431 and '329 patents require that the devices (e.g., beacons or fiducial implants) defining the body portions of interest be substantially fixed relative to one another and relative to such body portions. These systems generally function effectively when the devices defining the body portion of interest are inserted in bone, e.g., in a skull in connection with brain surgery or treatment, but are not believed to operate as intended when the devices are inserted in amorphous, pliable tissue.[0007]
• Breast lesions are typically excised with a scalpel manipulated directly by the surgeon. With the current emphasis on surgical therapies that conserve breast tissue, the above-described procedure for removing a breast lesion is typically performed through a narrow opening in the skin created by slitting and then pulling apart the skin. It tends to be difficult to manipulate the scalpel within this opening so as to remove the desired volume of tissue. The amorphous, pliable nature of breast tissue exacerbates removal of such tissue inasmuch as application of force to the scalpel causes movement of the breast tissue relative to the opening in the skin.[0008]
• Circular cutting tools are not widely used in surgery. Recently, however, United States Surgical Corporation of Norwalk, Conn., introduced a relatively small diameter, e.g., 5-20 mm, circular cutting tool identified by the trademark ABBI for removing a cylinder of breast tissue for biopsy purposes. The ABBI tool includes an oscillating, motorized, circular cutting blade that incises the breast tissue. While use of the ABBI tool is believed to be a relatively effective way to perform a core biopsies of breast tissue, it is not apparently designed to remove cylinders of tissue having a diameter much in excess of about 20 mm. As such, it is not adapted for use in surgeries involving the removal of relatively large tissue portions in a single cutting sequence. In addition, the effectiveness of the ABBI tool in therapeutic, rather than diagnostic, surgeries has not been confirmed.[0009]
• Detectors are used to locate organs or other portions of the body that have taken up a radioactive material, e.g., an antibody labeled with a radioactive material. For example, the gamma ray probe described in U.S. Pat. Nos. 5,170,055 and 5,246,005, both to Carroll et al., and sold by Care Wise Medical Products Corporation, Morgan Hill, Calif., and identified by the trademark C-TRAK, provides an audio output signal, the pitch of which varies with changes in relative proximity between the probe and a body portion that has taken up an antibody labeled with a gamma ray producing material, e.g., technetium 99. Once the body portion is detected, it is removed by known surgical techniques.[0010]
• Even with the systems and techniques described above, it remains difficult for a surgeon to remove a tissue mass in amorphous, pliable tissue, such as breast tissue, so as to ensure that the entire tissue mass is removed while at the same time conserving portions of adjacent tissue. As a result, more tissue surrounding the targeted tissue mass is typically removed than is desired.[0011]
SUMMARY
• The present invention is directed toward methods, systems, and system components for finding a target location within a human body. In one aspect of the invention, a system comprises a first wireless implantable marker configured to be implanted within the human body at a location relative to the target location, an instrument having a function-site and a first instrument marker connected to the instrument at a first predetermined site relative to the function-site, a position detection system, and a user interface. The position detection system can have a sensor that detects (a) a position of the first wireless implantable marker relative to a reference location and (b) a position of the first instrument marker relative to the reference location. The position detecting system can also include a computer that determines a relative position between the first wireless implantable marker and the first instrument marker based on the positions of the first wireless marker and the first instrument marker relative to the reference location. The user interface is operatively coupled to the position detection system. The user interface can have an indicator that denotes the position of the function-site of the instrument relative to the target location based on the relative position between the first wireless implantable marker and the first instrument marker.[0012]
• In another aspect of the invention, a wireless implantable marker comprises a biocompatible casing configured to be implanted into a human body relative to a target location within the human body, a signal element in the casing, and a fastener. The signal element is configured to emit a response energy in reaction to an excitation energy. The fastener is configured to hold the wireless marker at a reference location in a human body relative to the target location within the human body.[0013]
• Yet another aspect of the invention is an instrument for manipulation within a human or proximate to the human. The instrument can comprise a handle, a function-site coupled to the handle, and a first wireless instrument marker. The function-site is aligned with an alignment axis, and the first wireless instrument marker can be positioned along the alignment axis. The first wireless instrument marker is also configured to emit a wireless signal that can be detected by a position detection system to determine a position of the first wireless instrument marker relative to a reference location.[0014]
• The systems and components can be used in many applications in which it is desirable to accurately know the relative position between an instrument and a target location within a human body. For example, one embodiment of a method of treating a target location within a human body comprises exciting a wireless marker implanted in the body by emitting an excitation energy in a manner that causes the marker to emit a response energy. The method can continue by sensing the response energy and determining a position of the wireless marker relative to a reference location based on the sensed response energy. In other aspects, the method can also include determining a position of an instrument with a marker relative to the reference location, and displaying the relative position between the instrument and the target location. Other aspects of the invention are described in the following detailed description of the invention and the claims, and the accompanying drawings illustrate several embodiments of the invention.[0015]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an isometric view representative of a tissue mass and surrounding tissue volume that is bracketed by the markers, with two markers being positioned on opposite ends of each of mutually orthogonal X, Y and Z-axes intersecting the tissue mass so as to define the boundary of the tissue volume, and with the probe and detector being positioned adjacent the tissue volume in accordance with one embodiment of the invention.[0016]
• FIG. 1A is an isometric view of the tissue mass illustrated in FIG. 1, with two markers being positioned on opposite ends of each of mutually orthogonal X1, Y1 and Z-axes and with two markers being positioned on opposite ends of mutually orthogonal X2 and Y2-axes which are mutually orthogonal with respect to the Z-axis and offset along with Z-axis with respect to the X1 and Y1-axes.[0017]
• FIG. 1B is an isometric view of the tissue volume illustrated in FIG. 1, with two markers being positioned on opposite ends of each of V, W, X and Y-axes, all of which lie in a common plane and are mutually orthogonal with respect to a Z-axis, all of these axes intersecting the tissue mass.[0018]
• FIGS. 2[0019]a-2gare schematic representations of various embodiments of the markers of the present invention and their associated detection characteristics.
• FIG. 3[0020]ais a block diagram of the elements of one embodiment of the marker illustrated in FIG. 2c.
• FIG. 3[0021]bis a block diagram of the RF exciter used with the marker illustrated in FIG. 3a.
• FIG. 4 is a block diagram of the elements of one embodiment of the marker illustrated in FIG. 2[0022]e.
• FIG. 5 is a block diagram of the RF exciter used with the marker illustrated in FIG. 4.[0023]
• FIG. 6 is a perspective view of one embodiment of the marker illustrated in FIG. 2F, with details of internal construction being illustrated in phantom view.[0024]
• FIG. 7 is a block diagram of the probe and detector used with the marker illustrated in FIG. 2[0025]b.
• FIG. 8 is a block diagram of the probe and detector used with the marker illustrated in FIG. 2[0026]c.
• FIG. 9 is a front elevation view of a tissue anchor in accordance with one embodiment of the invention, with the cannula and rod of the cutter being shown in broken view to facilitate illustration.[0027]
• FIG. 10 is an enlarged view of the tissue anchor in FIG. 9, with the rod and cannula both being broken at first location and the rod alone being broken at a second location to facilitate illustration, also with the rod being shown in a retracted position relative to the cannula.[0028]
• FIG. 11 is similar to FIG. 10, except that the rod is shown in the extended position relative to the cannula, with the anchor members attached to the end of the rod being shown in an extended position engaged in a portion of a tissue mass.[0029]
• FIG. 12 is a top view of a breast of woman in a supine position, with a tissue mass being surrounded by markers of one embodiment of the present invention so as to define the tissue volume to be removed, and with an incision formed in the skin of the breast above the tissue volume.[0030]
• FIG. 13 is a cross-sectional view of the breast of FIG. 12 taken along line[0031]13-13 in FIG. 12.
• FIG. 14 is similar to FIG. 12, except that the skin adjacent the incision has been pulled apart to provide access to underlying breast tissue.[0032]
• FIG. 15 is an enlarged view of the incision of FIG. 14, with the tissue anchor illustrated in FIGS.[0033]9-11 being positioned in the tissue mass, and the two portions of a cutter illustrated being positioned adjacent the surgical cavity.
• FIG. 16 is similar to FIG. 13, except that an incision has been formed in the skin of the breast and retracted to provide access to the underlying tissue mass to be removed and the tissue anchor has been positioned above the breast.[0034]
• FIG. 17 is an enlarged view of the portion of the breast illustrated in FIG. 16 containing the tissue mass to be removed, with the tissue anchor being positioned in the tissue mass in the extended position so that the anchor members of the tissue anchor engage the tissue mass.[0035]
• FIG. 18 is similar to FIG. 15, except that two portions of a cutter are illustrated in engaged, cooperative relationship and are positioned under the skin in contact with the tissue volume to be removed.[0036]
• FIG. 19 is similar to FIG. 16, except that the tissue cutter is illustrated surrounding the tissue anchor and in cutting engagement with the tissue volume to be removed.[0037]
• FIG. 20 is similar to FIG. 19, except that the tissue volume has been completely removed from the breast and is illustrated immediately above the surgical opening in engagement with the tissue anchor and cutter.[0038]
• FIG. 21 is an isometric view of a system for locating and defining a target location within a human body in accordance with an embodiment of the invention.[0039]
• FIG. 22 is a schematic elevation view illustrating a portion of a system for locating and defining a target location within a human body.[0040]
• FIGS.[0041]23A-D are isometric cut-away views of wireless resonating markers in accordance with embodiments of the invention.
• FIGS.[0042]24-30 are side elevation views of several wireless implantable markers in accordance with embodiments of the invention.
• FIGS.[0043]31-33 are side elevation views of several wireless implantable markers in accordance with additional embodiments of the invention.
• FIGS.[0044]34-39 are isometric views of arrangements for implanting the wireless implantable markers relative to a target location T in accordance with embodiments of the invention.
• FIGS.[0045]40-43 are side cut-away views of instruments in accordance with embodiments of the invention.
• FIGS. 44 and 45 are schematic views of wireless controls for instruments in accordance with embodiments of the invention.[0046]
• FIGS.[0047]46-52 are isometric views illustrating several instruments in accordance with various embodiments of the invention.
• FIG. 53 is a partially schematic view illustrating an aspect of operating a system for locating and defining a target location within a human body in accordance with an embodiment of the invention.[0048]
• FIG. 54A is a front elevation view of an embodiment of a user interface in accordance with the invention.[0049]
• FIG. 54B is a graphical representation of calibrating a display coordinate system.[0050]
• FIGS.[0051]55-57 are front elevation views of several embodiments of user interfaces in accordance with various embodiments of the invention.
• FIGS.[0052]58A-58C are front elevation views of an embodiment of a user interface illustrating a method of operating the system in accordance with an embodiment of the invention.
• FIGS.[0053]59-61 are front elevation views of several additional user interfaces in accordance with more embodiments of the invention.
DETAILED DESCRIPTION
• The following description is directed toward systems and methods for locating and defining a target location within a human body. Several aspects of one system in accordance with an embodiment of the invention directed toward bracketing a target location with at least one marker are described below in Section I. Similarly, aspects of other systems in accordance with embodiments of the invention directed toward locating a target mass within a human body using the relative orientation between an implanted marker and an instrument are described below in Section II. Other aspects of embodiments of the invention directed toward defining and displaying a virtual boundary relative to a target location based on the location of an implanted marker are also described below in Section II.[0054]
• I. Systems and Methods for Delineating a Target Location Using Bracketing[0055]
• FIGS.[0056]1-20 illustrate a system and several components for delineating a target location within a human body in accordance with several embodiments of invention. Several of the components described below with reference to FIGS.1-20 can also be used in the systems set forth with respect to FIGS.21-61. Therefore, like reference numbers refer to like components and features throughout the various figures.
• Referring to FIG. 1, one aspect of the present invention is a[0057]system20 for defining the boundaries of, i.e., bracketing, atissue volume22 in atissue portion24. Typically,tissue volume22 will include atissue mass26, e.g., a breast lesion, that is targeted for removal and atissue margin28 of unaffected tissue surrounding the tissue mass. Aftertissue volume22 is bracketed,system20 can be used to locate the defined boundaries of the tissue volume, e.g., in connection with the surgical removal oftissue mass26. It will be appreciated that the invention can have other applications including radiation therapy, colo-rectal treatments, and many other applications in which it is useful to locate a target location other than a tissue volume within a human body.
• As described in more detail below, other aspects of the present invention are also directed to a method of bracketing[0058]tissue volume22 usingsystem20, and a method of removingtissue volume22 usingsystem20. These methods can be accomplished with other aspects of the present invention, such as markers, instruments, stabilizers/anchors, position detection systems and user interfaces described below.
• [0059]System20 comprises a plurality ofmarkers30, aprobe32 and adetector34 connected to the probe. As described in more detail below,markers30 are implanted intissue portion24 under the guidance of a conventional imaging system not forming part of the present invention, so as tobracket tissue volume22. Such imaging systems may include ultrasound, magnetic resonance imaging (“MRI”), computer-aided tomography (“CAT”) scan, and X-ray systems.Markers30 are imageable with the imaging energy generated by the imaging system. For example, if an ultrasound imaging system is used to implantmarkers30, the latter are configured and made from a material that strongly reflects ultrasound energy. Materials that are imageable with the energy generated by such systems are well known to those skilled in the art, and so are not described in detail here. Following implantation ofmarkers30,probe32 anddetector34 are used to locate the markers, as described in more detail below.
• The terms “[0060]probe32” and “detector34” are used generically herein to refer to all embodiments of the probe and detector described below. Specific embodiments of theprobe32 anddetector34 are identified using a prime notation described below, i.e., probe32′ ordetector34″. Additionally, the probes described below define one type of instrument, and the detectors described below define one type of position detection system in accordance with embodiments of the invention.
• A. Markers[0061]
• The[0062]markers30 can be biologically inert (biocompatible) and are relatively small so that they do not impair procedures for removing or treating atissue volume22.Markers30 may have different geometric configurations, e.g., spherical, disk-like, cylindrical, and other shapes. In one particular embodiment, the greatest dimension of amarker30 measured along a Y-axis extending through the marker from one surface to an opposite surface is not more than about 5 mm. Themarkers30 can be even smaller, e.g., the greatest dimension is about 1-2 mm, or they can also be larger. Although several of the markers with respect to FIGS.2-8 are described in connection with this aspect of the invention, they can also be used in connection with other aspects.
• In addition,[0063]markers30 each have a detection characteristic to enable detection byprobe32 anddetector34, or by a separate detection system with an array of sensors relative to a reference location. The detection characteristics of the various embodiments ofmarkers30 can be characterized as active or passive. In the active category, the detection characteristic of a first embodiment ofmarker30, illustrated in FIG. 2aasmarker30a, isgamma radiation40. In this regard,marker30amay include materials such as technetium 99, cobalt isotopes or iodine isotopes. Such materials may be obtained from DuPont of Billerica, Mass. Preferably, eachmarker30ageneratesgamma radiation40 having a field strength in the range of 1-100 microCuries.
• Also in the active category, in a second embodiment of[0064]marker30, illustrated in FIG. 2basmarker30b, the detection characteristic ismagnetic field42.Markers30bof the second embodiment thus contain ferromagnetic materials in which a magnetic field can be induced, or alternatively are permanently magnetized and so have an associated permanent magnetic field. In FIG. 2b,magnetic field42 represents both the induced and inherent magnetic fields. Strong permanent magnets, such as those made from Samarium-Cobalt, can be suitable magnets formarkers30b. Alternatively, the markers may communicate with the position detection system by resonating markers (e.g., AC magnetic coupling using coils of wire as receiving and emitting antenna), as described below with reference to FIGS.23A-D.
• Referring to FIG. 2[0065]c, in a third embodiment, again in the active category,marker30cemits radio frequency (“RF”)signal44 in response to a triggeringsignal46. Various energy sources may be used for triggeringsignal46, including a magnetic field, ultrasound or radio frequency energy. In this latter case,marker30cis preferably designed to receive triggeringsignal46 which has a first RF wavelength, and in response thereto, emitsignal44 of a second RF wavelength. In the simplest case, no data, other than the specific radio frequency itself, is carried insignal44. Alternatively,markers30cmay all transmitsignal44 at a single frequency, with data uniquely identifying each marker being carried insignal44 emitted by each marker.
• A[0066]suitable marker30cis illustrated in FIG. 3a. Thismarker30cincludes a transmit/receiveantenna52 for receiving an RF signal at a first frequency and transmitting an RF signal at a second frequency. Also included is a power detect/regulatecircuit54 connected toantenna52 that detects the presence of, and regulates, the RF signal received by the antenna. The regulated RF signal is provided fromcircuit54 to driveradio frequency generator56 which generates an RF signal at a second frequency. As discussed in more detail below, whenmultiple markers30care used together in a given bracketing procedure, preferably each marker transmits RF signals at a second frequency which is unique to the marker. The frequency of the receivedRF signal46, however, is preferably common with respect to all of themarkers30cused in the bracketing procedure. The RF signal generated byradio frequency generator56 is then provided toantenna52 where it is transmitted as an RF signal.
• Referring to FIG. 3[0067]b, anRF exciter device60 for generatingRF signal46 is illustrated.RF exciter60 includes aradio frequency generator62 for generatingRF signal46 at a predetermined frequency and anRF amplifier64 for amplifying the output from the radio frequency generator. The sensitivity ofamplifier64 may be controlled usinggain adjustment62 coupled to the amplifier. The output ofRF amplifier64 is provided to transmitantenna68 which transmitsRF signal46. Transmitantenna68 ofRF exciter60 is preferably placed in relatively close proximity tomarker30c, with appropriate gain adjustment ofRF amplifier64 being achieved bycontrol gain adjustment66 until a suitable return signal is absorbed fromdetector34″, discussed below and illustrated in FIG. 8.
• In a fourth embodiment, again in the active category,[0068]marker30d, illustrated in FIG. 2d, continuously emitssignal44 at specific frequencies in the radio frequency spectrum. Themarker30cillustrated in FIG. 3A and described above can be satisfactorily employed asmarker30dby adding a battery (not shown) in place of power detector portion ofcircuit54 ofmarker30c.RF exciter60 is not required in connection withmarker30d, insofar as the battery generates the energy used by the marker in producingRF signal44. The embodiments of the RF Markers are one example of a resonating marker having an electrical circuit in accordance with an embodiment of a wireless implantable marker.
• As a fifth embodiment in the active category,[0069]marker30e, illustrated in FIG. 2e, is designed to vibrate following implantation. This vibration is a detection characteristic that is chosen to enhance image contrast whenmarker30 is intended to be detected using aprobe32 anddetector34 that perform ultrasound imaging. More specifically,incoming ultrasound signal74 is reflected offmarker30eas reflectedultrasound signal76, with a Doppler shift component being added to the reflected signal due to the vibration of the marker to enhance imageability of the marker. The vibration frequency ofmarker30ewill vary depending upon the frequency of ultrasound energy generated byprobe32, but is preferably lower than the frequency ofincoming ultrasound signal74 which is typically 7.5 MHz, i.e., the vibration frequency is preferably in the 50 Hz to 50 kHz range. This embodiment is an example of a mechanical resonating marker in accordance with another embodiment of a wireless implantable marker.
• A[0070]suitable marker30ethat achieves the functionality described above is illustrated in FIG. 4. Thismarker30eincludes anantenna80 for receiving an RF signal that provides the energy driving the marker. A power detection andregulation circuit82 is connected toantenna80 for detecting when the antenna is receiving an RF signal and for regulating the signal for use by oscillator andwaveform generator circuit84 connected tocircuit82.Circuit84 converts the regulated RF signal received fromcircuit82 into an oscillating electrical signal, preferably in the audio frequency range (i.e., 20 Hz-20 kHz), having a waveform that is optimized to drivepiezoelectric device86 connected tocircuit84.Piezoelectric device86 is a conventional piezoelectric device of the type that converts an oscillating electrical input signal into mechanical oscillations.Piezoelectric device86 is attached viasupport88 toouter housing90 ofmarker30e.Housing90 is designed to resonate at the mechanical oscillation frequency ofpiezoelectric device86.
• Referring to FIG. 5, an RF coupled[0071]acoustic exciter92 is provided for generating the RF signal received byantenna80 ofmarker30e.Exciter92 includes aradio frequency generator94 for generating an RF signal.RF amp96, with again adjustment98 connected thereto, is provided for receiving and amplifying the output signal fromgenerator94. A transmitantenna100 is provided for receiving the output ofamp96 and transmitting the RF signal used to drivemarker30e. In use, gain98 ofamp96 is adjusted to amplify the RF signal produced bygenerator94 such thatmarker30eis caused to mechanically oscillate so it is most clearly observable by the ultrasound imaging system (not shown) used in conjunction withmarker30e.
• As those skilled in the art will appreciate, other circuit configurations may be used in[0072]marker30eto causepiezoelectric device86 to vibrate. For example, a frequency divider circuit (not shown) may be used in place of oscillator/waveform generator circuit84. With such alternative,exciter92 is modified to include a variable frequency oscillator (not shown) in place ofradio frequency generator94.
• In the passive category, the detection characteristic in a sixth embodiment of[0073]marker30, illustrated asmarker30fin FIG. 2f, is opacity toincoming ultrasound signal74. That is,marker30freflects incoming sound energy sufficiently to create a strong image in reflectedsignal76 so as to enhance imageability using a conventional ultrasound imaging system. In many cases, it will be advantageous to incorporate the detection characteristics ofmarker30finmarker30e.
• While those skilled in the art are familiar with materials and configurations that can be used for[0074]marker30f, onesuitable marker30fis illustrated in FIG. 6. Thismarker30fincludesplate102,plate104 andplate106, all of which are preferably arranged in mutually orthogonal relationship. It is preferred that each of the plates102-106 has a square configuration and the length of each edge of the plates, e.g., the length ofedge108 ofplate104, is preferably about twice the wavelength ofincoming ultrasound signal74. For example, whenincoming ultrasound signal74 has a wavelength of 7.5 MHz,edge108 has a length of about 2 mm. Plates102-106 are made from a material that strongly reflects ultrasound energy, e.g., aluminum, and typically have a thickness in the range of 10-100 μm. Plates102-106 ideally are enclosed in a biologicallynon-reactive casing110. The latter is preferably made from a material that does not have strong ultrasound reflection characteristics, e.g., a soft polymer.
• Also in the passive category,[0075]marker30gof the seventh embodiment, illustrated in FIG. 2g, comprises a capsule (not shown) filled with acolored dye78, e.g., a vital dye. Either or both the capsule and dye78 ofmarker30gare made from a material that is imageable by the imaging system, e.g., ultrasound, used to implant the markers, as described in more detail below. The capsule is made from gelatin or other suitable material that is selected to be sufficiently tough to withstand insertion intotissue volume22, but is relatively easily cut by the cutting tool used to remove the tissue volume, e.g., a conventional surgical scalpel or cuttingtool200 described below.Marker30gprovides a visual guide as to its location by releasingcolored dye78 when severed by a surgical cutting tool. In this regard,probe32 anddetector34 are not used in connection withmarker30g.
• [0076]Markers30a,30band30fmay be made from a solid structure containing material having the desired detection characteristic. Alternatively,markers30a,30band30fmay be made from a capsule filled with a dye, such as is used formarker30g, containing material having the desired detection characteristic. As another alternative, all embodiments ofmarkers30 may include a dye contained in an outer capsule having the requisite toughness and severability characteristics noted above.
• B. Probe and Detector[0077]
• The[0078]probe32 shown in FIG. 1 is one embodiment of an instrument, and thedetector34 shown in FIG. 1 is one embodiment of a user interface for any system in accordance with the invention. The design and configuration of theprobe32 and thedetector34 depend upon the embodiment ofmarker30 used. However, for all embodiments of marker30 (exceptmarker30g),detector34 is designed to provide humanly recognizable information whenprobe32 is positioned within a selected proximity, e.g., 1-5 cm, of a given marker. This information may take one of a variety of forms, including a burst of humanly perceivable sound, constant or intermittent illumination of a light, movement of a needle on a dial, a short burst of air, change of data in a visual display, increased image brightness or contrast (in the case whendetector34 is an ultrasound imaging system, as discussed below), a tactile response, or other humanly perceivable proximity information. In thisregard detector34 may include adial112, light114,speaker116, or other appropriate devices for generating the selected form of humanly perceivable information.
• Preferably, although not necessarily,[0079]detector34 provides humanly recognizable information that indicates changes in proximity ofprobe32 to a givenmarker30. Thus, rather than merely providing static or threshold information that probe32 is within a predetermined range of a givenmarker30,detector34 preferably provides proximity information having an attribute or characteristic that varies as a function of changes in proximity of the probe relative to the marker. For example, if the proximity information is sound, the pitch is varied with changes in proximity. Or, as another example, if the proximity information is light, the brightness of the light changes with changes in proximity.
• A probe and detector that may be satisfactorily employed as[0080]probe32 anddetector34, respectively, when the latter is intended to detectmaker30a, is sold by Care Wise Medical Products Corporation of Morgan Hill, Calif., and is identified by the trademark C-TRAK. The C-TRAK probe, which is described in U.S. Pat. Nos. 5,170,055 and 5,246,005 to Carroll et al., which are incorporated herein by reference, provides a humanly audible sound, the pitch of which varies with changes in proximity of the probe to tissue labeled with gamma ray producing material.
• Referring to FIGS. 1, 2[0081]band7, whenprobe32 anddetector34 are intended for use in detectingmarker30b, which generates amagnetic field42,probe32′ anddetector34′ illustrated in FIG. 7 may be satisfactorily employed. Probe32′ includes a conventional Hall effect sensor (not shown) that provides an output signal online120, the voltage of which varies as a function of proximity of the probe to the magnetic field generated by amarker30b.Detector34′ is connected to probe32′ vialine120, and includes anamplifier122 connected to line120 for amplifying the signal from the Hall effect sensor inprobe32′.Amplifier122 includes an offsetadjustment126 and again adjustment128. Offsetadjustment126 is provided to cancel the effects of any ambient magnetic fields, such as that of the earth.Gain adjustment128 is provided to control the overall sensitivity ofdetector34′. The amplified signal fromamplifier122 is delivered online124 to signalmeter126, which may comprise a dial with a movable needle, an LED or other device for representing signal strength. Also connected toline124 is voltage-controlledoscillator128, the output of which is provided toamplifier130. The output ofamplifier130drives speaker116. The frequency of the output signal from voltage controlledoscillator128 varies as function of changes in voltage of the signal delivered online124, which in turn causes the pitch of the sound produced byspeaker116 to vary as a function of changes in the voltage of the signal online124. As those of ordinary skill in the art will appreciate, other devices for providing humanly recognizable information representing changing proximity, e.g., a light, may be employed instead ofspeaker116.
• Referring to FIGS. 1, 2[0082]cand8, formarkers30cand30d, which generate radio frequency energy, probe32″ anddetector34″ are provided for use in detecting the markers.Probe32″ includes aconventional coil antenna140 for receiving an RF signal.Detector34″ includes aselectable notch filter142 connected toantenna140 which permits tuning of the detector to the unique RF frequency ofsignal44 emitted bymarkers30cor30d. A tuning knob or other user adjustable mechanism (neither shown) is attached toselectable notch filter142 to permit a user to perform such tuning. The output ofselectable notch filter142 is provided toRF amplifier144, the overall sensitivity of which may be controlled bygain adjustment146 attached to the amplifier. The output ofRF amplifier144 is provided to rectifier/integrator circuit148 which rectifies and time filters the signal. The output of rectifier/integrator circuit148 is provided to analogsignal strength display150 which provides a visual indication of the proximity ofprobe32″ tomarker30c. In addition, the output of rectifier/integrator circuit148 is provided tovoltage oscillator152 which generates an output signal, the frequency of which varies as a function of the voltage level of the signal provided by rectifier/integrator circuit148. The output signal of thevoltage control oscillator152 is amplified byaudio amplifier154, which in turn drivesspeaker116. Accordingly, the pitch of the sound generated byspeaker116 varies as a function of the strength of the RF signal received byprobe32″, and hence as a function of the proximity ofprobe32″ tomarkers30cor30d.
• A[0083]suitable probe32 anddetector34 for use with themarkers30eand30fis the ultrasound imaging system available from Dornier Surgical Products, Inc., Phoenix, Ariz., is identified by the name Performa, and generates ultrasound energy having a frequency of 7.5 MHz.
• C. Tissue Anchor[0084]
• Turning now to FIGS.[0085]9-11, another aspect of the present invention istissue anchor300. The latter is designed to stabilizetissue mass26 during surgical removal of themass using system20, as described in more detail below.
• [0086]Tissue anchor300 includes aring302 sized to receive the thumb or finger of a user, and arod304. The latter includes aproximal end305, which is attached to ring302, and adistal end306.Rod304 includes an outwardly projectingpin308 that serves as a stop, as described below.Tissue anchor300 also includes a plurality of, e.g., four,anchor members310 that are attached torod304 at or adjacent itsdistal end306. Typically,anchor members310 are attached torod304 so as to extend away from itsdistal end306, as illustrated in FIGS. 9 and 10. However, as an alternative design,anchor member310 may be attached torod304 so as to extend away fromdistal end306 toward proximal end305 (not shown). Eachanchor member310 may terminate with a barb312 (FIG. 11), if desired.Anchor members310 preferably have a curved configuration when in an unbiased state, as illustrated in FIGS. 9 and 11.Anchor members310 are preferably made from spring steel, although other “memory” metal alloys made also be satisfactorily used. In certain applications it may be unnecessary to provide a curve inanchor member310, i.e., the anchor member may be substantially straight.
• [0087]Rod304 preferably, although not necessarily, has a circular cross section. The outside diameter ofrod304 depends upon its intended application, but is typically in the range of 0.3-10 mm, preferably about 1-2 mm. The length ofrod304, as measured betweenproximal end305 anddistal end306, also depends upon its desired application, but typically ranges from 5-20 cm.
• [0088]Tissue anchor300 also includes acannula320 having acentral bore322, aproximal end324 and a pointeddistal end326. Central bore322 has an inside diameter that is sized to receiverod304 with a close sliding fit.Cannula320 has an outside diameter that is selected based on the intended application but is typically in the range 0.5 mm-12 mm, preferably about 1-3 mm.Cannula320 also includes anelongate slot328 that runs parallel to the long axis of the cannula and is sized to receivepin308 with a close sliding fit. The length ofslot328 is substantially the same as the length ofanchor members310.Slot328 includes apocket329 at its end closest todistal end326 ofcannula320 that extends orthogonally to the long axis of the slot and is sized to receivepin308.
• [0089]Cannula320 also includes a plurality ofapertures330 extending through the wall of the cannula.Apertures330 are positioned adjacentdistal end326 ofcannula320 whenanchor members310 are attached torod304 to extend away fromdistal end306 as illustrated in FIGS. 10 and 11. Ifanchor members310 extend fromdistal end306 toward proximal end305 (not shown), then apertures330 are moved toward the proximal end so that they are spaced from thedistal end326 at least about the length of the anchor members. Oneaperture330 is typically provided for eachanchor member310. The lengths ofanchor members310,cannula320, and slot328 are together selected so that a small portion, e.g., about 1 mm, of eachanchor member310 projects from itsrespective aperture330 whentissue anchor300 is in the retracted position illustrated in FIG. 10. In this position, pin308 engages the end ofslot328 closest toproximal end324.Anchor members310 are sized in this manner to ensure the anchor members remain positioned in theirrespective apertures330 whentissue anchor300 is in the retracted position illustrated in FIG. 10.
• The lengths of[0090]anchor members310,cannula320, and slot328 are also together selected so that most, if not substantially the entire, length of theanchor members310 projects from theirrespective apertures330 when tissue anchor is in the extended position illustrated in FIGS. 9 and 11. In this position, pin308 engages the end ofslot328 closest todistal end326.
• The elements of[0091]tissue anchor300 are preferably made from stainless steel, a plastic such as polystyrene or polyurethane, or other materials suitable for the intended application of the tissue anchor (as described in more detail below) known to those skilled in the art. As noted above, in many cases it is desirable to makeanchor members310 from spring steel or a “memory” metal alloy.
• D. Bracketing[0092]
• Referring now to FIGS. 1, 12 and[0093]13,markers30 may be used to bracket (i.e., define the boundaries of)tissue volume22 in atissue portion24 in accordance with the following method. In the following description of the method of bracketingtissue volume22, the latter is contained in a human breast. However, it is to be appreciated thattissue volume22 may be present in other hollow or solid organs and structures, e.g., a liver, or may constitute an entire organ or structure. Additionally, a plurality of themarkers30 may be implanted to completely bracket thetissue volume22, or one ormore markers30 can be used to bracket or otherwise mark the location of thetissue volume22.
• As the first step in bracketing[0094]tissue volume22, atissue mass26 of interest is identified through conventional imaging methods, e.g., ultrasound, MRI, X-ray or CAT scan. Next,markers30 are implanted intissue portion24 surroundingtissue mass26 and defining outer boundaries oftissue volume22. The number ofmarkers30 used, and the placement of the markers relative totissue mass26, will vary depending upon the location of the tissue mass relative to other types of tissue, e.g., bone or muscle, surgeon preference, size and configuration of the tissue mass and the desired amount of tissue margin28 (FIG. 1) beyond the edge oftissue mass26. However, in many applications, it may be desirable to use at least sixmarkers30 tobracket tissue volume22, preferably two on each of axes X, Y and Z (see, e.g., FIGS. 1, 12 and13). Two of themarkers30 can be positioned on each of axes X, Y and Z so as to lie on opposite boundaries oftissue volume22. For example, as illustrated in FIG. 1,marker30, lies on the Z-axis at the upper surface oftissue volume22,marker302 lies on the Z-axis at the lower surface of the tissue volume,marker303 lies on the X-axis at a first location on the outer surface of the tissue volume,marker304 lies on the X-axis at a second location on the outer surface of the tissue volume diametricallyopposite marker303,marker305 lies on the Y-axis at a third location on the outer surface of the tissue volume, andmarker306 lies on the Y-axis at a fourth location on the outer surface of the tissue volume diametricallyopposite marker305.
• Although the axes X, Y and Z can be mutually orthogonal, as illustrated, this is not mandatory and can be difficult to precisely implement in practice. In this particular embodiment, the[0095]tissue volume22 should be completely surrounded bymarkers30, i.e., the tissue volume should be defined in three dimensions by the markers. One notable exception to this that themarker30, such asmarker302 shown in FIGS. 1 and 13, positioned at the base of, i.e., underneath,tissue volume22 is not typically required when a different type of tissue, such as pectoral muscle400 (FIG. 13) is located at or near where the marker would be positioned. The illustration ofmarker302 in FIG. 13 is not inconsistent with this recommended placement regime formarkers30 because of the relatively great spacing between themarker302 andpectoral muscle400. Similarly, when themarker30, such asmarker30, shown in FIG. 1, to be positioned on top oftissue volume22 is near the skin overlying the tissue volume, such marker is not typically required. Also, while the X, Y and Z-axes are illustrated in FIG. 1 as intersecting at a common point centrally located withintissue mass26, this is not required. For example, it may be desirable to offset the X and Y-axes somewhat, as measured along the Z-axis. Furthermore, in some cases it may be desirable to definetissue volume22 withmarkers30 in only two dimensions or in only one dimension.
• In some cases, it will be desirable to use more than two[0096]markers30 on X, Y and Z-axes. Referring to FIG. 1A, in a first case, tenmarkers30 are used, two on the Z-axis, two on an axis X₁, two on an axis X₂that is offset along the Z-axis with respect to axis X₁, two on an axis Y₁, and two on an axis Y₂that is offset along the Z-axis with respect to axis Y₁. Referring to FIG. 1B, in a second case, tenmarkers30 are used, two on the X-axis, two on the Y-axis, two on the Z-axis, two on the V-axis which bisects the X and Y-axes and two on the W-axis which also bisects the X and Y-axes, but at a different location. Other numbers and relative placements of markers are also encompassed by the present invention.
• [0097]Markers30 are preferably spaced fromtissue mass26 so as to definetissue volume22 such thattissue margin28 is large enough to ensure none of the tissue mass of interest lies outside the tissue volume. This precise spacing will vary with the nature of thetissue mass26, the size of the tissue mass, surgeon preference and other factors. However,tissue margin28, as measured outwardly along an axis extending perpendicular to a surface location ontissue mass26, is generally about 0.5 cm to 3 cm, and is preferably about 1 cm to 2 cm. It will be appreciated that other margins may be more appropriate in other circumstances.
• [0098]Markers30 may be implanted intissue portion24 in a variety of different ways using a variety of different tools. In general,markers30 are implanted using a conventional imaging system (not shown) that simultaneously generates an image oftissue mass26 and the markers. By frequently comparing the location ofmarkers30 totissue mass26 during implantation of the markers intotissue portion24, based on image information received from the imaging system, the markers may be positioned so as to definetissue volume22 in the manner described above. As noted above,markers30 are made from a material that provides good image contrast with respect to the imaging energy used. In other aspects of the invention, only one or two markers may be implanted in or proximate to thetissue mass26, and themargin28 can be defined on a display by a virtual line or shape based upon the relative location between at least one of the implanted markers and thetissue mass26.
• It is preferable to at least partially immobilize[0099]tissue portion24 during implantation ofmarkers30. However, this is not necessary because, by comparing the relative location of amarker30 totissue mass26, the desired relative placement can typically be achieved even iftissue portion24 is moving during marker implantation.
• E. Marker Implantation[0100]
• Various techniques may be used to implant[0101]markers30 intissue portion24. With reference to FIGS. 12 and 13, one approach is to insertmarkers30 percutaneously throughskin402overlying tissue portion24 using known needle pushers or implanters (neither shown) of the type used to implant “seeds” of radioactive material for various cancer treatments. For example, needle pushers of the type sold by Best Industries of Springfield, Va., may be satisfactorily employed. These needle pushers include a central needle surrounded by an outer tube having an end plate or cup for supporting the radioactive “seed.” Following insertion of the needle pusher into the selected tissue mass, the radioactive “seed” is released by pressing the central needle downwardly relative to the surrounding outer tube, with the point of the needle ejecting the “seed” from the end plate or cup of the outer tube.
• To percutaneously insert[0102]marker30 in accordance with this first approach, the marker is positioned on the end of the needle pusher (in place of the radioactive “seed”), is forced throughskin402 and, using feedback from the imaging system, is guided to the region where it is desired to implant the marker. Then themarker30 is ejected from the needle pusher by urging the central needle forwardly into the inner tube.
• A second approach for implanting[0103]markers30 involves creating a small, e.g., 5-10 mm, incision (not shown) in theskin402overlying tissue portion24. Next, a scalpel is inserted through the incision so as to form a slit in the underlying tissue portion extending to the position where it is desired to implant amaker30. Then amarker30 is inserted through the slit to such position using a tweezers, needle pusher, trocar or other suitable tool.Other markers30 are implanted through separate incisions inskin402 in similar manner so as tobracket tissue volume22.
• Referring now to FIGS. 1 and 12-[0104]14, a third approach for implantingmarkers30 is to form a relatively large, e.g., 1-3 cm, incision404 (see FIG. 12) inskin402overlying tissue mass26. Next,incision404 is pulled open as illustrated in FIG. 14 using retractors or other conventional devices to form a relatively largeopen region406 abovetissue mass26.Markers30 are then implanted intotissue portion24 using either the first or second approaches described above. Other approaches for implantingmarkers30 so as tobracket tissue mass26 are also encompassed by the present invention. The speed and accuracy with whichmarkers30 may be implanted, and the trauma associated with implantation should be considered in selecting other approaches for implantingmarkers30.
• F. Marker Identification[0105]
• Once[0106]tissue mass26 has been bracketed or otherwise marked,tissue volume22 can be removed. As described in more detail below, one procedure involves identifying the boundaries oftissue volume22 using an embodiment ofprobe32 anddetector34 that is appropriate for the type ofmarker30 used, as discussed above. Using information fromdetector34 regarding such boundaries,tissue volume22 is then removed using a scalpel or other tool, withtissue anchor300 preferably, but not necessarily, being used to stabilize the tissue volume during removal. Another procedure is similar to the first, except thattissue anchor300 is not used.
• For both of these procedures, as the first step the surgeon typically identifies the boundaries of the tissue[0107]volume using system20 or otherwise marks the location of thetissue mass26 as described in more detail below. This step is generally needed because inpractice markers30 will often be implanted by another doctor, e.g., a radiologist, as a separate procedure. The boundaries oftissue volume22 are identified by movingprobe32 in the general region of the tissue volume and then monitoring the detection information (e.g., sound, light, dial movement, image clarity and the like) provided bydetector34. As noted above,detector34 may provide this information whenprobe32 is moved within a predetermined proximity of a givenmarker30, or may provide this information in a form that changes with changes in proximity of the probe to the marker (e.g., a light gets brighter as the probe is moved toward a marker and dimmer as it is moved away).
• The interaction between[0108]marker30 andprobe32 anddetector34 depends upon the detection characteristic of the marker. In the case ofmarker30a, which emits gamma radiation40 (FIG. 2a) on a continuous basis, a probe and detector of the type described in U.S. Pat. Nos. 5,170,055 and 5,246,005 to Carroll et al. (the “C-TRAK probe”), as discussed above, may be satisfactorily used to detect the markers. The C-TRAK probe includes a radiation detector, e.g., a scintillation crystal, which provides an output signal that is believed to vary as a function of the flux density of thegamma rays40 emitted bymarker30a. Changes in this output signal are then converted into humanly recognizable detection information, e.g., sound, having a characteristic, e.g., pitch or tempo in the case of sound, that varies with changes in gamma ray flux density. By observing the location ofprobe32 when the detection information fromdetector34 indicates the probe is closest to a givenmarker30a, the surgeon can mentally note where the marker is located. Repetition of this process will result in identification of the location of allmarkers30a.
• Referring to FIGS. 2[0109]band7, in the case ofmarker30b, which generates amagnetic field42,probe32′ anddetector34′ are used to detect the marker. To locate amarker30b, the surgeon movesprobe32′ in the general region oftissue volume22, with the result that as the probe approaches a givenmarker30bits Hall effect sensor (not shown) generates an output signal having a voltage that increases as the probe is moved toward the marker. Similarly the voltage of the output signal decreases asprobe32′ is moved away from themarker30b. The output signal ofprobe32′ is provided vialine120 toamplifier122, which amplifies the output signal from the probe. As discussed above, the amplified voltage signal fromprobe32′ is displayed onsignal meter126 and is also delivered to voltage controlledoscillator128. The latter generates an oscillating signal, the frequency of which varies as a function of the voltage of the amplified signal provided to voltage controlledoscillator128. This signal is then amplified byamplifier130, and the amplified signal then drivesspeaker116 such that the pitch of the sound provided by thespeaker116 varies as a function of proximity ofprobe32′ tomarker30b. By observingsignal meter126 and/or listening tospeaker116, the surgeon can assess when theprobe32′ is positioned closest to a selectedmarker30b. Repetition of this process will result in identification of the location of all ofmarkers30b.
• Turning now to FIGS. 2[0110]c,3a,3band8,marker30c, which generates anRF signal44, is identified usingprobe32″ anddetector34″ in the following manner.RF exciter60 is operated so as to produce anRF exciter signal46. More particularly, radio frequency generator62 (FIG. 3B) generates a radio frequency signal which is amplified byRF amplifier64, following sensitivity adjustment usinggain adjustment66, with the amplified signal being provided toantenna68 for transmission tomarkers30c.RF exciter60 is positioned sufficiently close tomarkers30cthatRF exciter signal46 is received byantenna52 of the markers and is of sufficient strength to driveradio frequency generator56 of the markers. Following detection and regulation by circuit54 (FIG. 3A) of thesignal46 received byantenna52,radio frequency generator56 generates an RF signal which is transmitted byantenna52 asRF signal44. Eachmarker30ccan transmitRF signal44 at a frequency that is unique to the marker, while anRF exciter signal46 having a single frequency can be used for all of themarkers30c, with the frequency ofsignal46 being different than the frequencies ofsignals44.
• Once[0111]exciter60 has been activated so as to causemarker30cto generateRF signal44, detection of the marker commences. This is achieved by positioningprobe32″ (FIG. 8) on oradjacent skin402adjacent tissue volume22, and then monitoring proximity information provided by analogsignal strength display150 and/orspeaker116 ofdetector34″. More specifically, following receipt ofRF signal44 by receiveantenna140 ofprobe32″, the signal is filtered byselectable notch filter142 ofprobe32″. By correlating a givenmarker30c, e.g.,marker30c₁, with a corresponding representation on the adjustment knob (not shown) that controlsselectable notch filter142, e.g., the reference number “1,” the surgeon can identify the location of the given marker. The knob for adjustingselectable notch filter142 is then moved to a different position when detecting asecond marker30c, e.g.,marker30c₂.
• Signals from receive[0112]antenna140 that are passed throughselectable notch filter142 are then amplified byRF amplifier144 with the adjustment of the amplifier gain being provided as needed usinggain adjustment146. The amplified signal is then provided to rectifier/integrator148 where the signal is rectified and time filtered. The strength ofsignal144 detected bydetector34″ is then displayed via analogsignal strength display150 and is provided to voltage controlledoscillator152. The latter creates an oscillating signal, the frequency of which varies as a function of the voltage of the signal provided by rectifier/integrator148. The output signal from voltage controlledoscillator152 is then amplified byaudio amplifier154 and delivered to drivespeaker116. The pitch of the sound provided byspeaker116 will vary as a function of the frequency of the signal provided by voltage controlledoscillator152, and as an ultimate function of the proximity ofprobe32″ to a givenmarker30c. By observing the location ofprobe32″ when the detection information fromdetector34″ indicates the probe is closest to a givenmarker30c, the surgeon can mentally note where the marker is located. By repeating this process for each of themarkers30cwith appropriate adjustment ofselectable notch filter142, all of themarkers30cmay be located.
• Referring to FIGS. 2[0113]d,3a,3band8,marker30dmay also be detected usingdetector34″ in substantially the same manner discussed above with respect tomarker30c. One significant difference, however, is the fact that RF exciter60 (FIG. 3B) is not used insofar asmarker30dcontains its own power source.
• Turning next to FIGS. 2[0114]e,2f, and4-6, formarkers30eand30f, which are designed to provide high image contrast when imaged with ultrasound,probe32 includes a conventional ultrasound transducer (not shown) that generates ultrasound in a conventional frequency range, e.g., 7.5 MHz, and receives back reflection of the ultrasound signal.Detector34 is the image processor and display (neither shown) of a conventional ultrasound apparatus which is connected to the ultrasound transducer.Markers30eor30fare identified by scanning the general region oftissue volume22 withprobe32, and monitoring the ultrasound image of the markers provided bydetector34. This ultrasound image permits the surgeon to identify the placement of all of the markers, and hence the boundaries oftissue volume22.
• In the case of[0115]marker30e, the latter is caused to vibrate at a frequency that is generally significantly less than that of the ultrasound generated by the ultrasound transducer inprobe32. This creates, through what is believed to be a Doppler shift phenomenon, enhanced image contrast in the ultrasound signal reflected offmarkers30e. Vibration of amarker30eis effected by operatingRF exciter92 so thatradio frequency generator94 generates a radio frequency signal which is amplified byamp96 and then transmitted byantenna100.Antenna80 ofmarker30ereceives this RF signal, which is detected and regulated bycircuit84 so as to generate an oscillating electrical signal that is provided topiezoelectric device86. This signal causes thepiezoelectric device86 to mechanically oscillate, which oscillations are transferred viasupport88 toouter housing90 ofmarker30e, thereby causing the housing (and hence the marker) to vibrate.
• G. Tissue Removal[0116]
• Following identification of[0117]tissue volume22 using the procedures outlined above, surgical removal of the tissue volume commences. Referring to FIGS. 12 and 14, the first of the two procedures for removingtissue volume22 referenced above commences with the formation of an incision404 (FIG. 12) inskin402 abovetissue volume22. The length ofincision404 is typically about equal to, or slightly greater than, the distance between twomarkers30 lying on a given axis, e.g., the Y-axis as illustrated in FIG. 12. Next, portions ofskin402adjacent incision404 are pulled apart by retractors or other known devices, so as to form open region406 (FIG. 14) and exposetissue portion24 beneath.
• Referring now to FIGS.[0118]9-11 and15-17, as the next step,tissue anchor300 is inserted intissue mass26 so as to assume the extended position illustrated in FIG. 11. This is achieved by inserting a finger intoring302, then pullingrod304 upwardly (as illustrated in FIG. 10) with respect tocannula320 so thatpin308 moves inslot328 toward the end thereof closest toproximal end324 of the cannula. In this retracted position,cannula320 is grasped and is inserted throughopen region406 intotissue volume22 so that itsdistal end326 is positioned substantially in the center oftissue mass26. This placement may be achieved under the guidance of an imaging system (not shown) that is capable of imagingtissue anchor300, e.g., ultrasound or X-ray imaging systems. Alternatively, usingsystem20, the location amarker302 lying beneathtissue volume22, as illustrated in FIGS. 16 and 17, is identified using the procedure described above to identify the tissue volume. By identifying the depth at whichmarker302 is located and comparing this to the length ofcannula320 inserted intotissue volume22,distal end326 may be positioned centrally withintissue mass26.
• Next,[0119]ring302, and hencerod304 attached thereto, is forced downwardly (as viewed in FIG. 15) relative to cannula320 untilpin308 contacts the end ofslot328 closest todistal end326. Asrod304 moves withincannula320 toward this extended position,anchor members310 are forced out throughapertures330 and into tissue mass26 (see FIG. 17). Then,ring302, and hencerod304, is rotated slightly so as to causepin308 to move intopocket329.
• The next step in the removal of[0120]tissue volume22 is assembly and placement of acutter200 inopen region406. Referring to FIGS. 15 and 18-20, thecutter200 includescutter portions202 and204 that can be positioned adjacentopen region406, as illustrated in FIG. 15. Next, thecutter portion202 is positioned inopen region406, and acurved plate206 of thecutter portion202 is inserted under portions ofskin402 adjacent the open region, as illustrated in FIG. 18. Next, thecutter portion204 is similarly positioned inopen region406. Then,cutter portions202 and204 are moved toward one another so thatcannula320 oftissue anchor300 is received in anelongate groove232 in acentral handle section222 and in anelongate groove255 in acentral handle section252.Cutter portions202 and204 are moved even closer to one another so thatcentral handle sections222 and252 engage one another. When positioned in this manner, ends ofcurved portion206 ofcutter portion202 engage ends ofcurved portion236 ofcutter portion204 so as to form a substantially continuous curved cutting edge. Also when positioned in this manner, a longitudinal axis ofcutter200 extends substantially parallel to the elongate axis ofcannula320, both of which are substantially co-axial with the Z-axis extending throughtissue volume22. (See FIGS. 16 and 19).
• Next, the position of[0121]cutter200 relative tomarkers30 is determined by comparing the location of markers, which is typically determined by usingprobe32 anddetector34 in the manner described above, to the position of the cutter. Then, the location ofcutter200 is adjusted so that the longitudinal axis ofcutter200 is substantially co-axial with the Z-axis of thetissue volume22, as illustrated in FIG. 19. In some cases the surgeon will recall the location ofmarkers30 from the prior marker identification step, and so it will be unnecessary to again locate the markers. However, whentissue portion24 is amorphous and pliable, as is the case when breast tissue is involved, it is recommended that this alignment ofcutter200 withtissue portions30 usingprobe32 anddetector34 be performed before any cutting oftissue volume22 commences.
• In connection with the initial insertion of[0122]cutter200 inopen portion406, an appropriatelysized cutter200 is selected such that the radius ofcurved plates206 and236, as measured radially outwardly from the longitudinal axis, is substantially the same as the radius oftissue volume22 as measured radially outward from the Z-axis. While this relationship between the radii ofcurved plates206 and236 ofcutter200 and the radius oftissue volume22, as measured with respect to Z-axis, is preferred, in some cases it may be satisfactory to use a cutter having a radius that is greater than or less than the radius of thetissue volume22. Also, the height ofcurved portions206 and236 is another factor considered in selecting anappropriate cutter200.
• Referring to FIGS.[0123]16-20, as the next step in the removal oftissue volume22,ring302 oftissue anchor300 is typically pulled upwardly in the direction of arrow F (see FIGS. 17 and 19) sufficiently totension tissue volume22 and adjacent portions oftissue portion24. By this tensioning oftissue volume22 andtissue portion24 the tendency of the tissue portion to compress under the force of a cutting device is reduced. Also, this tensioning oftissue volume22 serves to stabilize the tissue volume during the surgical removal process.
• In some cases, sufficient tissue stabilization can be achieved merely by holding[0124]tissue anchor300 in a substantially fixed position relative totissue volume22. In other words, no force in the direction of arrow F is applied totissue anchor300 except as may be necessary to hold the tissue anchor in a stable position.
• Then, while stabilizing[0125]tissue volume22 withtissue anchor300, preferably, but not necessarily by maintaining an upward force on the tissue anchor, the surgeon gripscutter200 and begins pressing downwardly towardtissue volume22, i.e., in the direction of arrow D (see FIG. 21). At the same time, the cutter is rotated about its longitudinal axis in either or both a clockwise and counterclockwise direction, e.g., in the direction indicated by curved arrow R (see FIG. 19). Theelongate grooves232 and255 (FIG. 15) are sized to permitcutter200 to rotate relatively freely aboutcannula320 positioned therein.
• As[0126]cutter200 is rotated about its longitudinal axis and is urged downwardly towardstissue volume22, it cutstissue volume22 along its outer boundary. Progress in removingtissue volume22 is generally periodically determined by comparing the position ofcurved plates206 and236 ofcutter200 relative tomarkers30 usingprobe32 anddetector34 to identify the locations ofmarkers30 and then comparing such locations with the location of the cutter. In particular, a determination can be made as to whentissue volume22 has been severed fromtissue portion24 to a depth defined by marker302 (FIG. 21) defining the bottom or innermost portion of the tissue volume. Thus, by iteratively comparing the position ofcutter200 to the locations ofmarkers30 using marker location information acquired fromdetector34 based on proximity information provided by the detector, a surgeon can determine when the cutting operation is completed andcutter200 can be removed fromtissue portion24, as indicated in FIG. 20.
• Depending upon the size of[0127]cutter200 relative to the placement ofmarkers30, the latter may remain in place intissue portion24 following removal oftissue volume22, as indicated in FIG. 20. If such as the case,markers30 are then subsequently removed by first locating themarkers using probe32 anddetector34 and then removing the markers with a suitable instrument, e.g., tweezers. In other cases, the markers will be included in thetissue volume22.
• In some cases, it will be necessary to sever the bottom or innermost portion of[0128]tissue volume22 fromtissue portion24 so as to permit removal of the tissue volume. A scalpel or other conventional tool may be used to perform this final severing of the tissue volume. The precise location where this final incision is made may be determined by again locating the position ofmarker302 usingprobe32 anddetector34. By leaningtissue anchor300 andcutter200 to one side, a surgeon can typically follow the incision created bycutter200 with a scalpel or other tool down to the region wheremarker302 is located andtissue volume22 remains attached totissue portion24.
• As noted above, in some circumstances a[0129]marker302 is not required when the bottom or innermost portion oftissue volume22 is positioned immediately above a different type of tissue, e.g., apectoral muscle400. In such case, the surgeon can assess whencutter200 has been inserted sufficiently deep intotissue portion24 by merely observing when bottom cutting edges of the cutter are about to engage the different type of tissue.
• Referring to FIG. 1A, by inserting[0130]markers30 at staggered locations along the Z-axis, the relative depth ofcutter200 intissue portion24 can be determined by locating specificmarkers using probe32 anddetector34. The location ofsuch markers30 is then compared with the location ofcutter200 to determine the depth of the cut. For example, ifmarkers30care installed at positions X₁and X₂in FIG. 1a, and each marker has a unique frequency, these markers can be uniquely identified bydetector34″ (FIG. 8) in the manner described above.
• Referring to FIG. 1B, by positioning more than four markers, e.g., eight markers as illustrated in FIG. 1B, the boundaries of[0131]tissue volume22 can often be more readily defined during the removal of the tissue volume. This is so because increasing the number ofmarkers30 used increases the quantity of information received fromdetector34 regarding the boundaries oftissue volume22.
• While the use of[0132]cutter200 in connection with theremoval tissue volume22 often expedites removal of the tissue volume, many other cutters or instruments can be used to remove, treat, monitor, or otherwise perform some procedure on the tissue volume. In this regard, a conventional scalpel may often be satisfactorily employed in place ofcutter200. Also, under certain circumstances it may be desirable to initiate an incision withcutter200, and then complete the incision with a scalpel. It will be appreciated that other types of cutters and systems for manipulating the tissue can be used, such as using as vacuum to pull-up on the tissue, extending an “umbrella” at the end of a stabilizer to pull-up on the tissue, vibrating the cutter to cut the tissue (either in lieu of or in addition to rotating the cutter), and using rotational electrocautery.
• The process of removing[0133]tissue volume22 using a scalpel also preferably commences by insertingtissue anchor300 intissue volume22 in the manner described above. The location ofmarkers30 are also determined prior to and during the removal oftissue volume22 by scalpel in the manner described above. Thus, during the removal oftissue volume22, the boundaries thereof may be repeatedly identified by locatingmarkers30 usingprobe32 anddetector34. As noted above, it is generally advantageous to usetissue anchor300 when removingtissue volume22 with a scalpel because by stabilizing the tissue volume and surrounding regions oftissue portion24, it is easier to maintain alignment of the scalpel with the boundaries of the tissue volume. However, it is to be appreciated that the use oftissue anchor300 is a preferred, but not essential, aspect of the present method of bracketing and removingtissue volume22.
• Referring now to FIG. 2[0134]gand FIG. 13, as noted above,probe32 anddetector34 are not used in connection withmarker30g. The detection characteristic ofmarkers30gis the release of acolored dye78 in surgical cavity adjacent the markers. In an alternative embodiment, the markers can be capsules that each have a different color, and the colored markers can be implanted in a manner to define the desired margin for guidance during a percutaneous biopsy procedure, excisional procedures, and other procedures. Removal of atissue volume22 bracketed bymarkers30gdiffers from the removal of tissue volume when bracketed by the other embodiments ofmarker30 in that the location ofmarker30gis not determined by the surgeon prior to initiation of the removal oftissue volume22. Practically speaking, this is more a difference in the process for removingtissue volume22 than a difference in the composition and construction ofmarker30g. This is so because for implantation purposes,marker30gmust necessarily be imageable by some form of imaging system, which imaging system could, in most cases, also be used by the surgeon to identify the location ofmarker30gprior to and in connection with the removal oftissue volume22. For example, ifmarker30gis initially implanted by imaging the marker using an ultrasound system, thenmarker30gis actually amarker30fThus, in connection with the following description of the process of removingtissue volume22 bracketed withmarkers30g, it is assumed the markers are not located by the surgeon prior to, or in connection with, the removal of tissue volume other than by visual observation, as discussed below.
• Removal of[0135]tissue volume22 bracketed bymarkers30galso preferably commences by installingtissue anchor300 as described above. Again, the use oftissue anchor300 is preferred, but not mandatory. Next, the surgeon commences cutting the general region oftissue volume22, which can be defined by colored marks, Kopanz needles or other known techniques. Then, the removal oftissue volume22 proceeds using eithercutter200, or a scalpel or other cutting device. As this removal oftissue volume22 is performed,tissue anchor300, if used, is manipulated to stabilizetissue volume22 in the manner described above. Ascutter200, the scalpel or other cutting device (e.g., a vacuum assisted cutting device) encounters amarker30g, the capsule of the marker is severed releasing thecolored dye78. This advises the surgeon that a boundary oftissue volume22 has been encountered. It may be advantageous to use a given color of dye inmarkers30gdefining one side of the boundary oftissue volume22, while themarkers30gdefining an opposite side include a different color of dye. By defining the boundary oftissue volume22 with a sufficient number, e.g., 10-25, ofmarkers30g, the boundary oftissue volume22 can typically be identified by iteratively cutting and observing whether dye appears in the surgical cavity.
• As noted above,[0136]marker embodiments30a-30fmay all includecolored dye78 within an outer capsule that is sufficiently tough to withstand insertion and yet is relatively easily cut bycutter200, a scalpel or other cutting device. Such use of dye inmarkers30 provides another source of information for the surgeon regarding the boundary oftissue volume22.
• One advantage of certain embodiments of the[0137]tissue bracketing system20 is that they permit the relatively precise identification of the boundaries oftissue volume22 without the need for needles, wires or other cumbersome apparatus projecting fromtissue portion24. As such,bracketing system20 permits a surgeon to relatively quickly and easily identify the tissue boundary oftissue volume22 and remove the tissue volume. In addition,system20 is ideally adapted for bracketing atissue volume22 in amorphous, pliable tissue, such as breast tissue.
• Another advantage of certain embodiments of the[0138]cutter200 is that they permit atissue volume22 of relatively large diameter to be removed through a relativelysmall incision404 or percutaneously. This advantage is useful in this era when tissue-conserving therapies are being emphasized.
• By stabilizing[0139]tissue volume22 usingtissue anchor300, the accuracy with which a surgeon can removetissue volume22 is also enhanced compared to techniques that do not use a tissue stabilizer or anchor. Also, the accuracy of removing tissue may be further enhanced by docking the tissue stabilizer or anchor to the first implanted tissue marker by using a first marker in the tissue stabilizer and the position detection system. This advantage of the present embodiment arises because tensioning of thetissue volume22 by pulling upwardly ontissue anchor300 serves to retain the tissue portion in a relatively stable position. Indeed, even holdingtissue anchor300 in a substantially fixed position relative to thetissue volume22 with which it is engaged typically provides beneficial stabilization of the tissue volume.
• While[0140]cutter200 andtissue anchor300 may be advantageously employed in connection with the present method of bracketing and removingtissue volume22, it is to be appreciated that the cutter and tissue anchor have application in many other contexts. More specifically, in any application in which it is desired to remove a volume of tissue through as small an incision as possible,cutter200 has utility. Similarly, when it is desired to stabilize a piece of tissue in connection with surgical removal or other treatment of the piece of tissue, whether or not within the bracketing context of the present invention,tissue anchor300 also has important application. Likewise, the system of bracketing a tissue mass is also useful in other applications, such as radiation therapy, and in connection with other body parts.
• Certain changes may be made in the above apparatus and processes shown in FIGS.[0141]1-20 without departing from the scope of the present invention. As such, it is intended that all matter contained in the preceding description or shown in the accompanying drawings shall be interpreted in an illustrative and not in a limiting sense. For example, as explained below with reference to FIGS.21-61, additional embodiments in accordance with other aspects of the invention are also useful for locating, monitoring, and or treating tissue masses and other body parts within a human body.
• II. Alternate Systems and Methods for Locating, Monitoring and/or Treating Target Locations Within a Human Body[0142]
• A. Overview of System Components and Operation[0143]
• FIG. 21 is an isometric view of a[0144]system1000 for locating a target location T within a human body H in accordance with one embodiment of the invention. The target location T shown in FIG. 21 can be a lesion, tumor, or other area of interest on or within a soft tissue region (e.g., a breast “B”), an organ, the colon, a bone structure, or another body part. The particular components of thesystem1000 are best understood in light of the relationship between the components and the operation of the system. Therefore, the following description will initially explain an overview of the components and the general operation of thesystem1000.
• In one embodiment, the[0145]system1000 includes a wirelessimplantable marker1100, aninstrument1120, aposition detection system1200, and auser interface1300. Thewireless implantable marker1100 can be implanted at a precise location with respect to thetarget location1000 using stereotactic imaging systems and other procedures known in the art as explained above. In operation, theposition detection system1200 determines the location of the wirelessimplantable marker1100 and the location of theinstrument1120 relative to a reference location to determine the relative position between the target location T and theinstrument1120. Theposition detection system1200 is coupled to theuser interface1300 to convey the relative position between thetarget location1000 and theinstrument1120 in a manner that allows a surgeon to intuitively understand the position and the orientation of theinstrument1120 relative to thetarget location1000 without additional imaging equipment. As a result, thesystem1000 is particularly useful for applications in which the patient cannot immediately proceed from an imaging procedure to another procedure, or when intraoperative imaging is not practical or economical.
• FIG. 22 is an elevational view illustrating selected embodiments of the wireless[0146]implantable marker1100, theinstrument1120, and a portion of theposition detection system1200 in greater detail. Thewireless implantable marker1100 can be one of the markers described above with reference to FIGS.1-20. Alternatively, thewireless implantable marker1100 can be a resonating marker or another type of marker as described below in more detail with reference to FIGS.23A-33. In general, at least onewireless implantable marker1100 is implanted at a location relative to thetarget location1000. In the embodiment shown in FIG. 22, onewireless implantable marker1100 is implanted within the target location T and another wirelessimplantable marker1100 is implanted adjacent to the target location T. In several embodiments, the wirelessimplantable markers1100 emit a response energy in reaction to an excitation energy emitted by theposition detection system1200. Theposition detection system1200 can sense the intensity of the response energy and determine the location of the individualimplantable markers1100 relative to a reference location.
• This implementation could be used with a device that is at a known location relative to the position detection system reference location. For example, an external beam radiation could be applied to a target location defined by the first implantable marker or otherwise monitored when the position of the beam applicator is known relative to the reference location of the position detection system. A suitable external beam radiation device is the PRIMIS Linear Accelerator from Siemens Medical of Concord, Calif.[0147]
• The[0148]instrument1120 can include ahandle1121, a function-site1124 coupled to thehandle1121, and at least oneinstrument marker1130. The function-site1124 can be a tip of theinstrument1120 or a portion of theinstrument1120 that cuts, ablates, deposits, images or otherwise treats or monitors the target location T. Several embodiments of various types of instruments with different function-sites are described in more detail below with reference to FIGS.40-52. Theinstrument markers1130 can be the same type of wireless markers as theimplantable marker1100, or alternatively theinstrument markers1130 can be a different type of wireless marker. Theinstrument markers1130 can also be “wired” markers that are directly coupled to theposition detection system1200. Theposition detection system1200 can also gauge theinstrument markers1130 to determine the position of the instrument relative to a reference location.
• In the embodiment shown FIG. 22, the[0149]instrument1120 includes threeinstrument markers1130 including twoinstrument markers1130 that are attached to theinstrument1120 along an alignment axis A-A, and athird instrument marker1130 that is offset from the alignment axis A-A. By knowing the distance between the function-site1124 and the array ofinstrument markers1130, theposition detection system1200 can determine the position and the orientation of the function-site1124 based upon the positions of the threeinstrument markers1130.
• Referring to FIGS. 21 and 22 together, the position detection system[0150]1200 (FIG. 21) can include a processor1202 (FIG. 21), adetection array1204 having a plurality ofsensors1210, and a transmitter1220 (FIG. 21). Thetransmitter1220 can emit an excitation energy that causes theimplantable markers1100 to emit a response energy. Eachsensor1210 can include three coils arranged orthogonally around a magnetic core to measure the response energy emitted from theimplantable markers1100 andinstrument1130. Theprocessor1202 calculates the distance between eachsensor1210 and each of themarkers1100 and1130 based upon the intensity of the response energy measured by thesensors1210. Theprocessor1202 also correlates the distance measurements between each of themarkers1100 and1130 to determine the individual locations of themarkers1100 and1130 relative to a reference location1230 (e.g., a reference coordinate system). Based upon this data, theprocessor1202 and/or another processor of theuser interface1300 can determine the relative position between the function-site1124 of theinstrument1120 and the target location T. Suitableposition detection systems1200 and resonating signal elements that can be adapted for use with theimplantable markers1100 and/or theinstrument markers1130 are available from Polhemus, Inc. of Burlington, Vt.
• B. Embodiments of Wireless Markers[0151]
• FIG. 23A is a cut-away isometric view of a resonating marker that can be used for the[0152]implantable markers1100 and/or theinstrument markers1130 in accordance with one embodiment of the invention. In this embodiment, the resonating marker includes acasing1140 composed of a biocompatible material, asignal element1150 within thecasing1140, and afastener1160. The biocompatible material of thecasing1140 can be a suitable polymeric material, metal, medical grade epoxy, glass, or other compound that can reside within a human body for a period of time. Thesignal element1150 can be a resonating circuit that includes acore1152, acoil1154 wrapped around thecore1152, and acapacitor1156 connected to thecoil1154. Thecore1152 may be a magnetically permeable material, such as a ferrite. Thesignal element1150 emits a response signal in reaction to an excitation energy at the resonate frequency of the circuit. As explained above, the excitation energy can be generated by the transmitter1220 (FIG. 21) of theposition detection system1200. In other embodiments, thesignal element1150 can be a mechanical resonator (e.g., piezoelectric actuator), an RF emitter, a fluorescent material, a bipolar semiconductor, or another suitable device or material that emits a response signal in reaction to an excitation energy. Thefastener1160 can have several different embodiments. In this particular embodiment, thefastener1160 is a shape-memory material that is straight in a stored position and coils to form a loop in a deployed position. The shape-memory material can be a spring, or it can be a substance that is straight at room temperature and coils at body temperature.
• FIG. 23B is an isometric cut-away view of another resonating marker in accordance with an embodiment of the invention. In this embodiment, the resonating marker includes a[0153]biocompatible casing1140 and asignal element1150a. The marker can also include a fastener (not shown in FIG. 23B). Thesignal element1150ahas three resonatingmembers1151a-carranged orthogonally with respect to each other. The resonatingmembers1151a-ccan also be configured in a non-orthogonal arrangement or any other suitable arrangement. Additionally, thesignal element1150acan include two or more resonating members such that this embodiment of the resonating marker is not limited to having three resonatingmembers1151a-c. Each resonatingmember1151a-ccan have aferrite core1152, acoil1154 wrapped around thecore1152, and acapacitor1156 coupled to eachcoil1154. Each resonatingmember1151a-ccan be tuned to resonate at the same frequency or at different frequencies. When the resonatingmembers1154a-cresonate at different frequencies, this embodiment of a resonating marker can thus provide three different signals from a single marker so that the position detection system can detect not only the point position of the marker (e.g. an X-Y-Z location), but also the pitch, roll and yaw of the marker relative to a coordinate system.
• FIGS. 23C and 23D illustrate a resonating marker in accordance with still another embodiment of the invention. In this embodiment, the resonating marker has a[0154]single core1152 and threecoils1154a-c. Eachcoil1154a-ccan be coupled to a capacitor (not shown), and eachcoil1154a-ccan generate a different signal. As such, this marker can be located in a manner similar to the marker described above with reference to FIG. 23B. Thecore1152 can accordingly be a ferrite block, and thecoils1154a-ccan be wrapped around the block orthogonally to each other as shown in FIG. 23D.
• The resonating markers shown in FIGS. 23A and 23B are particularly useful because they can remain within a human body for a long period of time. These resonating markers can also have frequencies that are useful in applications in which a plurality of[0155]wireless markers1100 are implanted. In such situations, it may be necessary to distinguish the implanted markers from one another. By using resonating markers that resonate at different frequencies, theposition detection system1200 can identify the “signature” of each marker by its unique frequency. A surgeon, therefore, can easily identify the relative location between a particular implantedmarker1100 and aninstrument1120.
• FIGS.[0156]24-30 are side elevation views of several implantable markers1101-1107 in accordance with embodiments of the invention. Each implantable marker1101-1107 shown in FIGS.24-30 has abiocompatible casing1140. Additionally, the implantable markers1101-1107 can also include asignal element1150 or1150afor emitting a resonating signal, such as a magnetic resonator, a mechanical resonator (e.g., a piezoelectric actuator), an RF emitter, a magnet, a fluorescent material, or other suitable elements that can emit a signal for detection by the position detection system1200 (FIG. 21).
• The implantable markers[0157]1101-1107 have different types offasteners1160. Theimplantable marker1101 shown in FIG. 24 includes afastener1160 defined by legs that project away from thecasing1140 in the deployed position. The legs can be molded projections of thecasing1140, or the legs can be small springs that are biased to project away from thecasing1140. Theimplantable marker1102 shown in FIG. 25 includes afastener1160 defined by shape-memory loops on both ends of thecasing1140. In FIG. 26, theimplantable marker1103 has afastener1160 defined by a surface texture, such as scales, that project away from thecasing1140. The surface texture of theimplantable marker1103 can be integrally formed with thecasing1140. Referring to FIG. 27, theimplantable marker1104 can include afastener1160 defined by one or more barbs or hooks. Referring to FIGS. 28 and 29, theimplantable markers1105 and1106 havefasteners1160 defined by a perforated material through which tissue can grow, such as a mesh. Theimplantable marker1105 shown in FIG. 28 has a perforated tip, and theimplantable marker1106 shown in FIG. 29 has a perforated tail. Referring to FIG. 30, theimplantable marker1107 includes afastener1160 defined by a spring or a serpentine element extending from the rear of thecasing1140. It will be appreciated that thefasteners1160 can have different configurations than the particular types offasteners1160 shown in FIGS.24-30.
• FIGS.[0158]31-33 are side elevation views of several embodiments of implantable markers1108-1110 in accordance with additional embodiments of the invention. The implantable markers1108-1110 can include thebiocompatible casing1140 for implantation into a human body. The implantable markers1108-1110 also include at least oneidentifier1170 that is on and/or in thecasing1140. Theidentifier1170 can be a radiopaque material that reflects radiation energy, an echogenic material that reflects ultrasound energy, and/or a groove or channel in thecasing1140 that can be observed by an imaging system. Alternatively, theidentifiers1170 can be a color or other marking that is visually distinguishable for viewing with a human eye. Theidentifiers1170 provide another feature for distinguishing one marker from another that can be used in addition to, or in lieu of, usingsignal elements1150 that emit different frequencies. The implantable markers1108-1110 can also includefasteners1160 as described above with reference to FIGS.24-30, and/orsignal elements1150 or1150aas described above with reference to FIGS. 23A and 23B.
• FIGS. 34 and 35 are isometric views of arrangements for implanting the wireless[0159]implantable markers1100 relative to the target location T in accordance with embodiments of the invention. FIG. 34 illustrates an embodiment in which only a firstwireless implantable marker1100ais implanted in the target location T, and FIG. 35 shows an embodiment in which only the firstwireless implantable marker1100ais implanted adjacent to or otherwise outside of the target location T. In either embodiment, the location of theimplantable marker1100arelative to the target location T is determined when themarker1100ais implanted or at another imaging procedure so that themarker1100aprovides a reference point for locating the target location T in subsequent procedures. Theuser interface1300 can electronically generate avirtual margin1301 relative to the target location based upon parameters defined by the physician and the location of theimplantable marker1100a. In other embodiments, it is not necessary to generate thevirtual margin1301 relative to the target location T. The physician can determine the shape of thevirtual margin1301 so that it defines a boundary for performing a particular procedure at the target location T. Thevirtual margin1301 is typically configured so that it defines the desired boundary for the particular procedure at the target location T without unduly affecting adjacent areas. In the case of a lesion in a soft tissue region, for example, the physician can define avirtual margin1301 that encompasses the lesion and an appropriately sized safety zone around the lesion that mitigates collateral damage to tissue proximate to the lesion. Thevirtual margin1301 can be spherical as shown in FIGS. 34 and 35, or it can have any desired shape including rectilinear shapes, oval shapes, or compound shapes.
• FIGS.[0160]36-39 are isometric views of additional arrangements for implanting the wirelessimplantable markers1100 relative to the target location T in accordance with other embodiments of the invention. FIG. 36 illustrates an embodiment in which six individualimplantable markers1100a-1100fare implanted in pairs along three orthogonal axes to define an excision boundary or another type of margin around the target location T. FIG. 37 shows an embodiment in which two individualimplantable markers1100aand1100bdefine a cylindrical margin around the target location T. FIG. 38 illustrates an embodiment in which individualimplantable markers1100aand1100bdefine an ovoid margin around the target location T, and FIG. 39 illustrates an embodiment in which fourimplantable markers1100a-1100ddefine a rectilinear margin around the target location T. The individualimplantable markers1100a-1100fcan define an actual margin by bracketing the target location T, or the positions of one or more of theindividual markers1100a-1110fcan be used to generate avirtual margin1301 for use with the user interface. Additionally, it will be appreciated that other arrangements for implanting theimplantable markers1100 and other types of margins can be used depending upon the particular procedure, the type of body part, and the shape of the target location T.
• C. Embodiments of Instruments[0161]
• FIGS.[0162]40-42 are cut-away side elevation views ofinstruments1120 in accordance with embodiments of the invention. Theinstruments1120 include thehandle1121, the function-site1124 coupled to thehandle1121, and at least oneinstrument marker1130. The position detection system1200 (FIG. 1) can determine the position of theinstrument markers1130 relative to a reference location. Referring to FIG. 40, this embodiment of theinstrument1120 includes asingle instrument marker1130aat a predetermined location relative to the function-site1124. The embodiment of theinstrument1120 shown in FIG. 40 provides at least a single position point for tracking by theposition detection system1200. When theinstrument marker1130 is a single-axis marker, such as the marker shown in FIG. 23A, theinstrument1120 can be displayed as a single point by the user interface1300 (FIG. 1). The orientation of this particular embodiment of theinstrument1120 cannot be displayed by theuser interface1300 because the single-axis marker does not provide sufficient data to determine the angle of the alignment axis A-A relative to a plane through the target location T (FIG. 1) or the rotational position of theinstrument1120 around the alignment axis A-A. It may be possible, though, to have asingle instrument marker1130 define the location and orientation of theinstrument1120 if theposition detection system1200 and theinstrument marker1130 are sensitive enough to pinpoint the location and orientation of thesingle instrument marker1130. For example, the multiple-axis markers shown in FIGS.23B-D are expected to provide sufficient data to define the location and orientation of theinstrument1120 using a single marker.
• FIG. 41 illustrates another embodiment of the[0163]instrument1120 having afirst instrument marker1130aand asecond instrument marker1130b. Thefirst instrument marker1130ais positioned at a first predetermined location relative to the function-site1124, and thesecond instrument marker1130bis positioned at a second predetermined location relative to the function-site1124. The first andsecond instrument markers1130aand1130bcan be positioned along the alignment axis A-A as shown in FIG. 41, or at least one of themarkers1130aor1130bcan be offset from the alignment axis A-A. The embodiment of theinstrument1120 shown in FIG. 41 accordingly provides two position points that theposition detection system1200 can track. As a result, theposition detection system1200 can determine the angle of the alignment axis A-A relative to a reference plane so that theuser interface1300 can display theinstrument1120 as (a) a vector of varying length when the alignment axis A-A is not normal to the reference plane, or (b) as a point when the alignment axis A-A is at least approximately normal to the reference plane. When theinstrument markers1130aand1130bare multiple-axis markers, the rotational orientation of theinstrument1120 relative to the alignment axis A-A can be determined such that both the position of the function-site1124 and the orientation of theinstrument1120 can be displayed by theuser interface1300.
• FIG. 42 illustrates yet another embodiment of the[0164]instrument1120 having afirst instrument marker1130a, asecond instrument marker1130b, and athird instrument marker1130c. The first andsecond instrument markers1130aand1130bcan be positioned along the alignment axis A-A, but thethird instrument marker1130cis offset from the alignment axis A-A. This embodiment of theinstrument1120 provides three position points for tracking by theposition detection system1200. As a result, theposition detection system1200 can determine (a) the angle of the alignment axis A-A relative to a reference plane, and (b) the rotational orientation of theinstrument1120 around the alignment axis A-A. The embodiment of theinstrument1120 shown in FIG. 42 accordingly permits theuser interface1300 to show the angle of the function-site1124 relative to a reference plane, and the orientation of a leading edge of the function-site1124 relative to the motion of theinstrument1120.
• FIG. 43 is a side elevational view of an embodiment of the[0165]instrument1120 including awireless control1132 for controlling an aspect of (a) theinstrument1120, (b) theposition detection system1200, and/or (c) theuser interface1300 in accordance with another embodiment of the invention. Theinstrument1120 shown in FIG. 43 has threeinstrument markers1130a-c, but will be appreciated that theinstrument1120 can have any of one ormore instrument markers1130. Thewireless control1132 includes anactuator1133 and atransmitter1134 coupled to theactuator1133. Thetransmitter1134 transmits or otherwise emits a signal indicating a control parameter. Thetransmitter1134, for example, can be another marker that theposition detection system1200 can track. In one particular embodiment, thetransmitter1134 is a resonating magnetic marker having asignal element1150 as set forth above with respect to FIG. 23. One advantage of using a resonating marker for thetransmitter1134 is that the system1000 (FIG. 21) can be controlled by awireless instrument1120 using theposition detection system1200 without additional types of receivers (e.g., RF systems) that add to the complexity and cost of thesystem100. Alternatively, thetransmitter1134 can be an RF device, a mechanical resonator, a permanent magnet, or another type of device that emits a frequency or another form of energy. When thetransmitter1134 is a marker, theposition detection system1200 detects the position of thetransmitter1134 and generates a control signal according to the position of thetransmitter1134.
• FIG. 44 is a schematic view of one embodiment of the[0166]wireless control1132. In this embodiment, thetransmitter1134 of thewireless control1132 is a resonating marker having a resonating signal element1150bsimilar to one of thesignal elements1150 or1150ashown above in FIG. 23A or23B. The signal element1150bincludes aferrite core1152, acoil1154 wrapped around thecore1152, acapacitor1156 coupled to thecoil1154, and a cut-off switch1157 between thecoil1154 and thecapacitor1156. Theactuator1133 can be a push-button coupled to the cut-off switch1157 that breaks the circuit to deactivate the signal element1150b. In operation, the physician can press theactuator1133 to close the cut-off switch1157 so that the signal element1150bemits a resonating signal. Theposition detection system1200 detects the signal from the signal element1150band generates a control signal that changes a parameter of thesystem1000. Theposition detection system1200, for example, can send a message to theuser interface1300 to change a display of theuser interface1300 to show the relative position between theinstrument1120 and one of several implantedmarkers1100. This is particularly useful when a plurality ofmarkers1100 are implanted, such as the implantedmarkers1100a-fin FIG. 36, and the physician needs to know the position relative to a particular marker. In one embodiment, thecontrol1132 can be used to cycle through thevarious markers1100a-fby depressing the actuator1133 to move from one marker to the next. Thewireless control1132 can also have several other applications that allow theposition detection system1200 to control other aspects of thesystem1000 based upon input at theinstrument1120.
• FIG. 45 is a schematic view of another embodiment of the[0167]wireless control1132. In this embodiment, theactuator1133 is a slider mechanism that moves along thehandle1121, and thetransmitter1134 is another marker that can be detected by theposition detection system1200. Theactuator1133, for example, can be a linear slider or a rotational slider that has “click-stops” to indicate various control positions. In operation, the relative distance between thetransmitter1134 and a fixed marker attached to the instrument (e.g., thesecond instrument marker1130b) is determined by theposition detection system1200. A parameter of theinstrument1120, theposition detection system1200, and/or theuser interface1300 can be controlled according to the relative distance between thetransmitter1134 and the fixed marker. For example, if the distance between thetransmitter1134 and thesecond instrument marker1130bis D₁, theuser interface1300 may display the distance between the function-site1124 of theinstrument1120 and a first implanted marker. Similarly, if the distance between thetransmitter1134 and thesecond instrument marker1130bis D₂, theuser interface1300 may display the relative distance between the function-site1124 and a second implanted marker.
• FIGS.[0168]46-52 illustrateseveral instruments1120a-gin accordance with various embodiments of the invention. Theinstruments1120a-gcan each include ahandle1121, a function-site1124 coupled to thehandle1121, and at least oneinstrument marker1130 similar to theinstruments1120 described above with reference to FIGS.40-42. Theinstruments1120a-gcan also include a wireless control similar to the wireless controls1132 described above with reference to FIGS.43-45. The differences between theinstruments1120a-gis generally the type of function-site1124.
• FIG. 46 illustrates a[0169]smart Bovie1124athat has a function-site1124adefined by an RF cutting blade. Suitable RF cutting devices without theinstrument markers1130 are available from Valley Lab of Boulder, Colo., under the part number E2516 Reusable Electrosurgical Pencil. FIG. 47 illustrates ascissors1120bthat has a function-site1124bdefined by the cutting blades. FIG. 48 illustrates aharmonic scalpel1120chaving a function-site1124cdefined by a harmonic cutting tip. Suitable harmonic scalpels without theinstrument markers1130 are available from Ethicon Endo Surgery of Cincinnati, Ohio, under the part name ULTRACISION HARMONIC SCALPEL®. FIG. 49 illustrates alaproscope1120dhaving a function-site1124ddefined by a distal end of the laproscope. Suitable laproscopes without theinstrument markers1130 are available from US Surgical of Norwalk, Conn., under the part name SURGIVIEW® Multi-Use Disposable Laproscope. FIG. 50 illustrates anRF ablation device1120ehaving a function-site1124ewith RF elements1137 through which RF energy is delivered to the target site T. The RF elements1137 can be retractable into a cannula in a manner similar to the tissue anchors310 described above with reference to FIGS. 10 and 11. SuitableRF ablation devices1120ewithout theinstrument markers1130 are available from Radio Therapeutics Sunnyvale, Calif., under the part name LeVeen Needle Electrodes. FIG. 51 illustrates arobotic probe1120fhaving a function-site1124fdefined by a distal tip of theprobe1120fTheprobe1120fcan be used to mark reference fiducials just prior to a surgical procedure to map out a desired cutting path. FIG. 52 illustrates ascalpel1120ghaving a function-site1124gdefined by a cutting blade. Suitable scalpels withoutinstrument markers1130 are available from Bard-Parker of Franklin Lake, N.J., such as single-use Scalpel No. 11. It will be appreciated that FIGS.46-52 illustrate only a few of the types of instruments for use with the system1000 (FIG. 21), and that other types of instruments can be used with thesystem1000 by addinginstrument markers1130 that theposition detection system1200 can track.
• D. Embodiments of User Interfaces[0170]
• FIGS.[0171]53-61 illustrate several embodiments ofuser interfaces1300 and methods for using thesystems20 and1000 in accordance with the invention. Theuser interfaces1300 can be used with any of theimplantable markers30 and1100, and any of theinstruments200,300 and1120 described above with reference to FIGS.1-52. Theuser interface1300 is generally a computer display for graphically illustrating or otherwise presenting the position data generated by theposition detection system1200 to a user. Theuser interface1300 can alternatively be an audio signal, a visual pattern based on light and/or color, a tactile or mechanical signal (e.g., vibrational), or other indicators that can inform a physician of the relative position between the instrument and the target location.
• FIG. 53 is a schematic diagram illustrating an embodiment of the[0172]system1000 for displaying the relative position between aninstrument1120 and the target location T. In this embodiment, thesystem1000 includes animplantable marker1100 implanted in the body part B, aninstrument1120 for performing a procedure on the target location T, theposition detection system1200, and theuser interface1300. Theimplantable marker1100 and theinstrument1120 can be any one of the embodiments of these devices described above. Theinstrument1120, more specifically, has an instrument coordinatesystem1129 defined by the orthogonal axes X_i-Y_i-Z_i. The Z_i-axis is aligned with the alignment axis A-A, and the X_i-axis and Y_i-axis define an operating plane normal to the Z_i-axis. The instrument coordinatesystem1129 moves with the instrument during the procedure. Theposition detection system1200 generally includes the same components described above with reference to FIGS. 21 and 22. As such, theposition detection system1200 can include anarray1204 havingsensors1210 and atransmitter1220 for emitting an excitation energy that drives the implantedmarker1100 and theinstrument markers1130. Theposition detection system1200 can also include a reference coordinatesystem1212 defined by three orthogonal axes X_r-Y_r-Z_r. In operation, theposition detection system1200 determines the position of the implantedmarker1100 and the positions of theinstrument markers1130 relative to the reference coordinatesystem1212 to determine the relative position between the function-site1124 of theinstrument1120 and the target location T. Theposition detection system1200 can also include a processor.
• The[0173]user interface1300 provides a display or another type of indicator of the relative position between the function-site1124 and the target location T based on data from theposition detection system1200. In this embodiment, theuser interface1300 includes aprocessor1302, amemory1304 coupled to theprocessor1302, aninput device1306 for controlling parameters of thesystem1000, and anoutput display1310. Theprocessor1302 and thememory1304 can be a computer available from many sources. Theinput device1306 can be a keyboard, a computer mouse, a touch screen, or any other suitable device for inputting commands to theprocessor1302. Theoutput display1310 is preferably a display screen, but it can also be another type of output device that generates an output that can be detected and understood by a user. Theuser interface1300 also includes a display coordinatesystem1308 defined by three orthogonal axes X_d-Y_d-Z_d. The display coordinatesystem1308 can initially correspond to the reference coordinatesystem1212 of theposition detection system1200. In many applications, however, it may not be desirable to view thedisplay1310 based upon the reference coordinatesystem1212. Theprocessor1302 can accordingly calibrate the display coordinatesystem1308 so that thedisplay1310 shows a desired two-dimensional plane or a desired three-dimensional space.
• In operation, the[0174]user interface1300 processes data from theposition detection system1200 in real-time to show the relative motion between the function-site1124 and the target location T. For example, theprocessor1302 receives signals from theposition detection system1200 and produces output signals that can be represented by theoutput display1310. As explained in more detail below, the user can set the parameters for generating thevirtual margin1301 and controlling other aspects of theuser interface1300 using theinput device1306.
• FIG. 53 also illustrates an orientation between the[0175]instrument1120 and the target location T that generally corresponds to a calibrating stage of a procedure for treating, probing, or monitoring the target location T. The surgeon typically holds theinstrument1120 so that the alignment axis A-A of theinstrument1120 defines a desired Z_ielevation axis along which the surgeon moves theinstrument1120 up and down relative to the target location T. The X_i-Y_iplane normal to the Z_i-axis defines the desired operating plane in which the surgeon moves theinstrument1120 along a margin M around the target location T during a procedure. When the physician holds theinstrument1120 relative to the target location T in a desired orientation for performing the procedure, the instrument coordinate system1129 (X_i-Y_i-Z_i) may not be aligned with the reference coordinate system1212 (X_r-Y_r-Z_r) and the display coordinate system1308 (X_d-Y_d-Z_d). Theuser interface1300 accordingly calibrates the display coordinatesystem1308 to coincide with the instrument coordinatesystem1129 so that theuser interface1300 indicates movement of instrument1120 (a) along the alignment axis A-A as an elevation relative to the target location T, and (b) through the operating plane X_i-Y_ias a location in an X-Y grid of thedisplay1310.
• FIG. 54A illustrates one embodiment of the[0176]user interface1300 showing the relative position between theinstrument1120 and the target location T before calibrating theposition detection system1200 to align the display coordinate system1308 (FIG. 53) with the instrument coordinate system1129 (FIG. 53). In this embodiment, thedisplay1310 has a two-dimensional grid1320 that shows the X_d-Y_dplane of the display coordinatesystem1308. Thedisplay1310 can also include anumerical elevation indicator1332 and/or agraphical elevation indicator1334. Theelevation indicators1132 and1134 show the position along the Z_d-axis of the display coordinatesystem1308. Theinstrument1120 is displayed as a line on thegrid1320 because theuser interface1300 has not yet been calibrated to align the display coordinatesystem1308 with the instrument coordinatesystem1129. The function-site1124 of theinstrument1120 appears as a point at one end ofinstrument1120, and the elevation of the function-site1124 relative to the target location T is displayed by one or both of theelevation indicators1332 and1334. At this stage before calibrating theuser interface1300, it may be difficult for a physician to determine the relative position between the function-site1124 and the target location T because moving theinstrument1120 along the alignment axis A-A simultaneously changes the position of the function-site1124 on thegrid1320 and on theelevation indicators1332 and1334. Therefore, to provide a more intuitive display of the motion of theinstrument1120, theposition detection system1200 aligns the display coordinatesystem1308 with the instrument coordinatesystem1129.
• Referring to FIG. 54B, an example of an algorithm for performing the calibration transformation is described as follows. The definitions include Azimuth=ψ; Elevation=θ; Point before transformation=(a,b,c). The mathematical equation to convert this point into the X′,Y′,Z′ coordinate system; (a′,b′,c′). In the user interface, the marker would be at (0,0,0) after the implementation of the algorithms. The X, Y, Z axis would still be oriented with the original coordinate system of the system reference. First rotate about the z-axis by the azimuth angle or ψ. The point in this intermediary coordinate system is now defined as:[0177]
• p=a*cos(ψ)+b*sin(ψ)
• q=b*cos(ψ)−a*sin(ψ)
• r=c
• Next, rotate about the y-axis so that the z-axis is in line with the probe. Effectively rotation will be about the y-axis by the elevation angle −90° or (θ−90°). The point in the X′,Y′,Z′ coordinate system would now be defined as:[0178]
• a′=p*sin(θ)−r*cos(θ)
• b′=q
• c′=p*cos(θ)+r*sin(θ)
• Substituting the values of p, q, and r into these equations the following equation is obtained in terms of the original coordinates and the azimuth and elevation angles:[0179]
• a′=[a*cos(ψ)+b*sin(ψ)]*sin(θ)−c*cos(θ)
• b′=b*cos(ψ)−a*sin(ψ)
• c′=[a*cos(ψ)+b*sin(ψ)]*cos(θ)+c*sin(θ)
• The point (a′,b′,c′) represents the original point (a,b,c) transformed into the new coordinate system. The user interface display probe tip projection math length projection on X-Y display plane is defined by the equation:[0180]
• Display Length=length probe tip*cosine(Elevation angle)
• Based on these algorithms, a person skilled in the art can program the[0181]user interface1300 to perform the calibration without undue experimentation.
• FIG. 55 illustrates an embodiment of the[0182]user interface1300 of FIG. 54 after theposition detection system1200 calibrates theuser interface1300 to align the display coordinatesystem1308 with the instrument coordinatesystem1129. In this embodiment, theinstrument1120 and the function-site1124 are both displayed as a point location on thegrid1320. The elevation of the function-site1124 relative to the target location T still appears as a numeric or graphical readout on theelevation indicators1332 and1334. After calibrating the coordinate systems, theuser interface1300 accordingly shows (a) movement of theinstrument1120 solely along the alignment axis A-A by changing only the readout on theelevation indicators1332 and1334 without changing the location of theinstrument1120 on thegrid1320, and (b) movement of theinstrument1120 solely through the operating plane X_i-Y_iby changing only the location of theinstrument1120 on thegrid1320 without changing the readout on theelevation indicators1332 and1334. Theposition detection system1200 and/or theuser interface1300 can alternatively continuously calibrate thesystem1000 so that the display coordinatesystem1308 continuously coincides with the instrument coordinatesystem1129. In such an embodiment, thegrid1320 is continuously normal to the alignment axis A-A of theinstrument1120 such that thedisplay1310 continuously displays theinstrument1120 as a point location (as shown in FIG. 55) irrespective of the orientation of theinstrument1120.
• FIGS. 54A and 55 also illustrate one embodiment for defining a[0183]virtual margin1301 relative to the target location T for use on thedisplay1310 of theuser interface1300. As described above with reference to FIGS.34-39, thevirtual margin1301 can be generated based upon the position of animplantable marker1100 or a plurality ofimplantable markers1100. Thevirtual margin1301 is generally defined by a physician based upon information from an imaging procedure, such as when themarkers1100 are implanted. Thevirtual margin1301 can be configured to include a lesion, tumor, or other mass that defines the area of interest at the target location T. Thevirtual margin1301 should be configured to avoid removing or otherwise performing a procedure on material outside of thevirtual margin1301. As such, after determining the relative position between theimplantable marker1100 and the target location T using an imaging process (e.g., radiation, MRI, ultrasound, etc.), the physician determines the desiredvirtual margin1301 to input into theuser interface1300.
• The physician can input the desired[0184]virtual margin1301 into theuser interface1300 using theinput device1306 of theuser interface1300 or an instrument1120 (e.g., theprobe1120fshown in FIG. 51). In one embodiment using a keyboard, the physician can enter a desired radius relative to the target location T to define a spherical or cylindricalvirtual margin1301 that is displayed as a circle on thegrid1320 of thedisplay1310. As explained above, thevirtual margin1301 can also be configured to be rectilinear, a compound shape, or any other suitable two-dimensional or three-dimensional shape that is defined by the physician. Theuser interface1300 accordingly displays the selected avirtual margin1301 to define a boundary relative to the target location T. For example, thevirtual margin1310 is often configured to completely surround or encompass a tissue mass or other body part within the target location T. Referring still to FIGS. 54 and 55, this embodiment of the invention illustrates a singleimplantable marker1100 disposed in the target location T and a spherical or cylindricalvirtual margin1301 around theimplantable marker1100.
• FIG. 56 illustrates another embodiment for defining a[0185]virtual margin1301 relative to a target location T. In this embodiment, theuser interface1300 can display an outline of the target location T (shown in broken lines), but it will be appreciated that the target location T may not be displayed on thegrid1320. This embodiment of the invention illustrates a singleimplantable marker1100 disposed outside of the target location T by an offset distance having coordinate differentials of “X” along an X-axis of thegrid1320, “Y” along the Y-axis of thegrid1320, and “Z” (not shown) along an axis normal to a plane defined by thegrid1320. The offset distance can be determined during a previous imaging procedure or when theimplantable marker1100 is implanted using known radiation, MRI, ultrasound and other imaging techniques. Based upon the position of theimplantable marker1100 and the offset distance between theimplantable marker1100 and the target location T, theuser interface1300 can generate thevirtual margin1301 around the actual location of the target location T. One advantage of implanting themarker1100 outside of the target location T is that theimplantable marker1100 does not pierce the tissue mass or other body part of the target location T. This feature can be particularly useful in applications for removing cancerous tissue masses or other types of tissue/bone masses that are desirably left intact until they are removed from the patient.
• FIG. 57 illustrates another embodiment for defining a[0186]virtual margin1301 relative to the target location T. In this embodiment, twoimplantable markers1100aand1100bhave been implanted at two separate offset distances relative to the target location T. The physician can input two separatevirtual margins1301aand1301brelative to the individualimplantable markers1100aand1100b, respectively. In this particular embodiment, thevirtual margin1301ais relative to the firstimplantable marker1100aand defines a cylindrical boundary. Similarly, thevirtual margin1301bis relative to the secondimplantable marker1100b, but it defines a spherical boundary. Thevirtual margins1301aand1301btogether define a compound virtual margin relative to the target location T. It will be appreciated that several other virtual margins can be developed using different combinations of one or more implantable markers, and different combinations of markers that are implanted in and/or offset from the target location T. In any of the embodiments of thevirtual margins1301 described above, the physician can manipulate aninstrument1120 relative to the target location T using theuser interface1300 to display the relative position between the function-site1124 of theinstrument1120 relative to thevirtual margin1301.
• FIGS.[0187]58A-58C illustrate a procedure for operating thesystem1000 in accordance with one embodiment of the invention. In this example, a singleimplantable marker1100 has been implanted within the target location T and theuser interface1300 has generated a cylindrical or sphericalvirtual margin1301 around the target location T. Referring to FIG. 58A, theinstrument1120 is shown after the display coordinate system has been calibrated to be aligned with the instrument coordinate system in the manner explained above with reference to FIGS.53-55. Theuser interface1300 initially displays theinstrument1120 as a point at a location A. Based upon this display, the physician understands that the alignment axis A-A of theinstrument1120 is normal to thegrid1320 of thedisplay1310, and that the function-site1124 of theinstrument1120 is at an elevation of 5 cm above a predetermined reference plane relative to the target location T and/or the implanted marker1100 (see the elevation indicator1332). The physician then moves theinstrument1120 transverse relative to the alignment axis A-A to a location B on thevirtual margin1301. In this particular embodiment, the physician held theinstrument1120 at a constant elevation of 5 cm above the reference plane shown by theelevation indicator1132.
• FIG. 58B illustrates a subsequent stage of operating the[0188]system1000. After moving theinstrument1120 from location A to location B (FIG. 58A), the physician inserts the function-site1124 ofinstrument1120 into the body part to move the function-site1124 from the location B to a location C. Referring to both FIGS. 58A and 58B, theelevation indicator1132 shows that the elevation of the function-site1124 relative to the reference plane has moved from 5 cm above the reference plane to 2 cm below the reference plane. In an application in which the physician wants to excise a cylindrical tissue mass having a base 2 cm below the reference plane, theinstrument1120 at location C is accordingly ready to be moved along thevirtual margin1301 to excise a mass of tissue. Referring to FIG. 58C, theuser interface1300 displays the motion of the instrument as the physician or robot moves it along thevirtual margin1301. Thevirtual margin1301 accordingly provides a guide to the physician that allows the physician to excise a precise volume of tissue without cutting into the target mass or damaging tissue outside of the target location T.
• FIG. 59 illustrates another embodiment of the[0189]user interface1300 in accordance with the invention. In this embodiment, thedisplay1310 includes afirst grid1320 illustrating a top view relative to a reference plane and asecond grid1420 illustrating a front view normal to the reference plane. For purposes of convention, the reference plane can be parallel to the table on which the patient is positioned during a procedure, but it can also be at an angle to the table. Thedisplay1310 can also include anelevation indicator1132 showing the elevation of the function-site1124 relative to the target location T and adistance indicator1432 showing the point-to-point distance between the function-site1124 and the target location T. The embodiment of thedisplay1310 shown in FIG. 59 provides the physician two separate views that the physician can use to more accurately position the function-site1124 relative to the target location T. The operation and the advantages of thedisplay1310 illustrated in FIG. 59 are expected to be similar to those described above with reference to FIGS.55-57.
• FIGS. 60 and 61 illustrate additional embodiments of the[0190]user interface1300 in accordance with the invention. Referring to FIG. 60, thedisplay1310 provides a three-dimensional solid or opaque representation of thevirtual margin1301. FIG. 61 illustrates an embodiment in which thedisplay1310 provides a holographic representation of thevirtual margin1301 such that the target location T can be represented within the holographic representation. Suitable software for generating the three-dimensional representations of thevirtual margin1301 illustrated in FIGS. 60 and 61 is available from Medical Media System of West Lebanon, N.H. The three-dimensional representations of thevirtual margin1301 also provide a physician with an intuitive understanding of the relative position between the function-site1124 of theinstrument1120 and thevirtual margin1301 relative to the target location T. It is expected, therefore, that the three-dimensionalvirtual margins1301 will also allow physicians to accurately perform procedures or monitor internal target locations within a human body without additional imaging equipment or procedures.
• From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.[0191]

Claims (86)

What is claimed is:

1. A system for locating a target location within a human body, comprising:

a first wireless implantable marker configured to be implanted within the human body at a location relative to the target location;

an instrument having a function-site and a first instrument marker connected to the instrument at a first predetermined site relative to the function-site;

a position detection system having a sensor that detects a position of the first wireless implantable marker relative to a reference location and a position of the first instrument marker relative to the reference location, wherein the position detecting system includes a computer that determines a relative position between the first wireless implantable marker and the first instrument marker based on the positions of the first wireless marker and the first instrument marker relative to the reference location; and

a user interface operatively coupled to the position detection system, the user interface having an indicator that denotes the position of the function-site of the instrument relative to the target location based on the relative position between the first wireless implantable marker and the first instrument marker.

2. The system ofclaim 1 wherein the user interface comprises a graphical display having a boundary relative to the first implantable marker, and wherein the boundary defines a margin relative to the target location.

3. The system ofclaim 1 wherein the user interface comprises a graphical display having a two-dimensional grid defining a plane and a boundary in the grid relative to the first implantable marker, and wherein the grid and the boundary define a margin relative to the target location in the plane.

4. The system ofclaim 1 wherein the user interface comprises a graphical display having a two-dimensional grid defining a plane, an elevation indicator providing an elevation of the function-site relative to the plane, and a boundary in the grid relative to the first implantable marker, and wherein the grid and the boundary define a margin relative to the target location in the plane.

5. The system ofclaim 1 wherein the elevation indicator comprises a numeric readout and/or a graphical representation.

6. The system ofclaim 1 wherein the marker comprises a radioactive isotope, and the position detection system comprises a device that detects a radiation level.

7. The system ofclaim 1 wherein the user interface comprises a graphical display having a three-dimensional representation that defines a margin relative to the target location.

8. The system ofclaim 1 wherein the user interface comprises a graphical display having a three-dimensional representation that defines an area relative to the function site of the instrument.

9. The system ofclaim 1 wherein the user interface comprises a graphical display having a first three-dimensional boundary relative to the first implantable marker and a second three-dimensional boundary relative to the second implantable marker, and wherein the first and second three-dimensional boundaries define a three-dimensional margin relative to the target location.

10. The system ofclaim 1 wherein the user interface comprises a graphical display having an opaque three-dimensional representation that defines a margin relative to the target location.

11. The system ofclaim 1 wherein the user interface comprises a graphical display having an opaque three-dimensional representation that defines a target an area relative to the function site of the instrument.

12. The system ofclaim 1 wherein the user interface comprises a graphical display having a first three-dimensional boundary relative to the first implantable marker and a second three-dimensional boundary relative to the second implantable marker, and wherein the first and second three-dimensional boundaries define a three-dimensional margin relative to the target location.

13. The system ofclaim 1 wherein:

the system further comprises a second wireless implantable marker configured to be implanted within the human body relative to the first implantable marker and the target location;

the position detection system also detects a position of the second wireless implantable marker relative to the reference location; and

the user interface provides an indicator of the position of the function-site of the instrument relative to the target location based on the relative position between the first wireless implantable marker and the first instrument marker, and/or a relative position between the second wireless implantable marker and the first instrument marker.

14. The system ofclaim 13 wherein the user interface comprises a graphical display having a first boundary relative to the first implantable marker and a second boundary relative to the second implantable marker, and wherein the first and second boundaries define a margin relative to the target location.

15. The system ofclaim 13 wherein the user interface comprises a graphical display having a two-dimensional grid defining a plane, a first boundary in the grid relative to the first implantable marker, and a second boundary in the grid relative to the second implantable marker, and wherein the first and second boundaries define a margin relative to the target location in the plane.

16. The system ofclaim 1 wherein:

the instrument further comprises a second instrument marker connected to the instrument and aligned with the first instrument marker along an alignment axis;

the position detection system also detects a position of the second instrument marker relative to the reference location; and

the user interface provides an indicator of the position and orientation of the function-site based on the positions of the first and second instrument markers relative to the reference location.

17. The system ofclaim 1 wherein the instrument further comprises a second instrument marker connected to the instrument and aligned with the first instrument marker and the function-site along an alignment axis.

18. The system ofclaim 1 wherein:

the instrument further comprises a second instrument marker connected to the instrument and aligned with the first instrument marker and the function-site along an alignment axis; and

the user interface comprises a graphical display having a two-dimensional grid defining a plane, an elevation indicator providing an elevation of the function-site relative to the plane, and an indicator showing the instrument as a point on the grid when the alignment axis is approximately normal to the plane or as a line when the alignment axis is not approximately normal to the plane.

19. The system ofclaim 18 wherein the grid and the boundary define a margin relative to the target location in the plane.

20. The system ofclaim 18 wherein the user interface includes a line that varies in length relative to degree that the alignment axis is not normal to the plane.

21. The system ofclaim 1 wherein:

the instrument further comprises a second instrument marker connected to the instrument at a second site and a third instrument marker connected to the instrument at a third site, wherein at least one of the second and third instrument markers are not aligned with the first instrument marker along an alignment axis;

the position detection system also detects a position of the second instrument marker and a position of the third instrument marker relative to the reference location, and

the user interface provides an indicator of the position and orientation of the function-site based on the positions of the first, second, and third instrument markers relative to the reference location.

22. The system ofclaim 1 wherein the instrument further comprises a wireless control for selecting a mode of operating the user interface.

23. The system ofclaim 22 wherein the wireless control comprises a cut-off switch that temporarily defeats a location functionality of the first instrument marker.

24. The system ofclaim 22 wherein:

the first instrument marker comprises a magnetic marker attached to the instrument; and

the wireless control comprises a magnetic shield that blocks a magnetic field of the magnetic marker to defeat location functionality of the first instrument marker.

25. The system ofclaim 22 wherein:

the first instrument marker comprises a mechanical resonator marker attached to the instrument; and

the wireless control comprises a dampening mechanism that cancels mechanical vibrations of the mechanical resonator to defeat location functionality of the first instrument marker.

26. The system ofclaim 22 wherein:

the wireless control comprises a slider marker that moves from a first position to a second position relative to the first instrument marker; and

the position detection system detects a position of the slider marker relative to the first instrument marker, and a functionality of the system is changed according to the relative position between the slider marker and the first instrument marker.

27. The system ofclaim 1 wherein the instrument further comprises a wireless control for selecting a mode of operating a component of the system.

28. The system ofclaim 27 wherein the wireless control comprises a cut-off switch that temporarily defeats a location functionality of the first instrument marker.

29. The system ofclaim 27 wherein:

the first instrument marker comprises a magnetic marker attached to the instrument; and

the wireless control comprises a magnetic shield that blocks a magnetic field of the magnetic marker to defeat location functionality of the first instrument marker.

30. The system ofclaim 27 wherein:

the first instrument marker comprises a mechanical resonator marker attached to the instrument; and

the wireless control comprises a dampening mechanism that cancels mechanical vibrations of the mechanical resonator to defeat location functionality of the first instrument marker.

31. The system ofclaim 1 wherein:

the instrument further comprises a second instrument marker along the alignment axis;

the user interface comprises a graphical display having a two-dimensional grid defining a plane, wherein the user interface continuously displays the two-dimensional plane orthogonal relative to the alignment axis.

32. The system ofclaim 1 wherein the instrument comprises a tissue stabilizer probe.

33. The system ofclaim 1 wherein the instrument comprises a cutting tool.

34. The system ofclaim 33 wherein the cutting tool comprises a scalpel.

35. The system ofclaim 33 wherein the cutting tool comprises a minimally invasive cutting device.

36. The system ofclaim 33 wherein the cutting tool comprises a bovie knife.

37. The system ofclaim 33 wherein the cutting tool comprises an ultrasonic cutting device.

38. The system ofclaim 16 wherein the cutting tool comprises scissors.

39. The system ofclaim 1 wherein the instrument comprises a radio frequency tissue ablation probe.

40. The system ofclaim 1 wherein the instrument comprises cryogenic tissue ablation probe.

41. The system ofclaim 1 wherein the instrument comprises interstitial laser probe.

42. The system ofclaim 1 wherein the instrument comprises a laproscopic probe.

43. The system ofclaim 1 wherein the instrument comprises a robotic surgery probe.

44. A system for locating a target location, comprising:

a first wireless implantable marker configured to be implanted into a body at a location relative to the target location, wherein the first wireless marker emits a wireless signal; and

a position detection system having an energy source that emits an excitation energy and a sensor that detects a position of the first wireless implantable marker relative to a reference location.

45. The system ofclaim 44, further comprising a user interface coupled to the position detection system, wherein the user interface includes an indicator of a boundary relative to the first wireless marker defining a desired margin around the target location.

46. The system ofclaim 44, further comprising a user interface coupled to the position detection system, wherein the user interface includes an indicator of a first target position relative to the first wireless marker defining the target location.

47. A wireless marker for implantation, comprising:

a biocompatible casing configured to be implanted into a human body relative to a target location within the human body;

a signal element in the casing, the signal element being configured to emit a response energy in reaction to an excitation energy; and

a fastener configured to hold the wireless marker at a reference location in a human body relative to the target location within the human body

48. The wireless marker ofclaim 47 wherein the signal element comprises an electronic circuit resonator.

49. The wireless marker ofclaim 47 wherein the signal element comprises a magnetic resonator.

50. The wireless marker ofclaim 47 wherein the signal element comprises a radio frequency marker.

51. The wireless marker ofclaim 47 wherein the signal element comprises a mechanical resonator.

52. The wireless marker ofclaim 47 wherein the signal element comprises a magnet.

53. The wireless marker ofclaim 47 wherein the signal element comprises a fluorescent material.

54. The wireless marker ofclaim 47 wherein the fastener comprises a protrusion integral with the casing.

55. The wireless marker ofclaim 47 wherein the fastener comprises an adhesive material.

56. The wireless marker ofclaim 47 wherein the fastener comprises a protein that binds and/or adheres to tissue.

57. The wireless marker ofclaim 47 wherein the fastener comprises a polymer that binds and/or adheres to tissue.

58. The wireless marker ofclaim 47 wherein the fastener comprises a biasing member that is biased to expand from a stored position to a deployed position.

59. The wireless marker ofclaim 47 wherein the fastener comprises a biasing member that is biased to contract from a stored position to a deployed position.

60. The wireless marker ofclaim 47 wherein the fastener is a spring material element that forms a loop to grasp tissue in a deployed position.

61. A wireless marker for implantation, comprising:

a biocompatible casing configured to be implanted into a human body relative to a target location within the human body; and

an identifier on and/or in the casing that can be observed by an imaging system to distinguish the casing from other casings that have been implanted into the human body.

62. The wireless marker ofclaim 61 wherein the identifier comprises metal bands around the casing.

63. The wireless marker ofclaim 61 wherein the identifier comprises a shape of the casing.

64. The wireless marker ofclaim 61, further comprising a fastener configured to hold the wireless marker at a reference location relative to the target location, and wherein the identifier comprises a shape of the fastener.

65. A wireless marker for implantation, comprising:

a biocompatible casing configured to be implanted into a human body relative to a target location within the human body; and

an identifier on and/or in the casing that can be observed visually to distinguish the casing from other casings that have been implanted into the human body.

66. The wireless marker ofclaim 65 wherein the identifier comprises metal bands around the casing.

67. The wireless marker ofclaim 65 wherein the identifier comprises a shape of the casing.

68. The wireless marker ofclaim 65, further comprising a fastener configured to hold the wireless marker at a reference location relative to the target location, and wherein the identifier comprises a shape of the fastener.

69. The wireless marker ofclaim 65 wherein the identifier comprises unique colors of the wireless marker casing.

70. An instrument for manipulation within a human, comprising:

a handle;

a function-site coupled to the handle, the function-site being aligned with an alignment axis;

a first instrument marker along the alignment axis; and

a second instrument marker along the alignment axis.

71. An instrument for manipulation within a human, comprising:

a handle;

a function-site coupled to the handle, the function-site being aligned with an alignment axis; and

a first wireless instrument marker along the alignment axis, wherein the first wireless instrument marker emits a wireless signal that can be detected by a position detection system to determine a position of the first wireless instrument marker relative to a reference location.

72. An instrument for manipulation within a human, comprising:

a handle;

a function-site coupled to the handle, the function-site being aligned with an alignment axis;

a first wireless instrument marker along the alignment axis, wherein the first wireless instrument marker emits a wireless signal that can be detected by a position detection system to determine a position of the first wireless instrument marker relative to a reference location; and

a user interface attached to the instrument and coupled to the detection system, wherein the user interface includes an indicator of a relative position between the function-site and a target location within the human.

73. A system for locating a target location within a human body, comprising:

an instrument having a handle, a function-site coupled to the handle, and at least one instrument maker attached to the instrument at a predetermined location relative to the function-site; and

a detection system that detects a characteristic of the instrument marker and determines a configuration of the instrument and/or the function-site.

74. The system ofclaim 73 wherein the instrument marker configuration comprises a location of the instrument marker.

75. The system ofclaim 73 wherein the instrument marker configuration comprises a marker resonator frequency.

76. A method of providing information for a procedure in which a first wireless implantable marker is implanted in a human body relative to a target location and an instrument marker is coupled to an instrument at a predetermined site relative to a function-site on the instrument, the method comprising:

emitting a resonating energy from the first wireless implanted marker;

sensing a location of the first wireless marker relative to a reference location;

sensing a location of the instrument marker relative to the reference location;

correlating a relative position between the first wireless marker and the instrument marker based on the sensed locations; and

determining a relative position between the function-site and the first wireless implanted marker by adding together the relative position between the first wireless marker and the target location, a relative position between the instrument marker and the function-site, and the relative position between the first wireless marker and the instrument marker.

77. The method ofclaim 76, further comprising:

comparing the position of the function-site to the target location; and

providing an indication of the position of the function-site relative to the target location.

78. The method ofclaim 76 wherein, if the first wireless marker is implanted in the target location, then the method further comprises generating a virtual margin to extend at least partially around the marker.

79. The method ofclaim 76 wherein, if the first wireless marker is implanted adjacent to the target location such that the marker in offset from the target location, and the method further comprises generating a virtual margin to extend at least partially around the target location.

80. A method of treating a target location within a human body, comprising:

exciting a wireless marker implanted in the body by emitting an excitation energy in a manner that causes the marker to emit a response energy;

sensing the response energy; and

determining a position of the wireless marker relative to a reference location based on the sensed response energy.

81. The method ofclaim 80, further comprising directing an intra-operative radiation energy relative to the determined position of the wireless marker.

82. The method ofclaim 80, further comprising monitoring an intra-operative radiation energy relative to the determined position of the wireless marker.

83. The method ofclaim 80, further comprising directing an external beam radiation energy relative to the determined position of the wireless marker.

84. The method ofclaim 80, further comprising monitoring an external beam radiation energy relative to the determined position of the wireless marker.

85. The method ofclaim 80, further comprising directing a brachy radiation energy relative to the determined position of the wireless marker.

86. The method ofclaim 80, further comprising monitoring brachy radiation energy relative to the determined position of the wireless marker.

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