Ultrasonouraohy Training Phantom
Technical Field
The invention relates to methods of manufacturing phantoms for use as medical 5 ultrasonography training aids, and to phantoms manufactured in accordance with such methods.
Background
Ultrasonography phantoms are physical models that simulate anatomical tissue. 10 Phantoms are used to train medical practitioners to perform ultrasonography procedures such as diagnostic imaging and ultrasound guided interventions. Phantoms provide a safe and convenient tool for training medical practitioners.
It is desirable for phantoms to simulate the ultrasound reflection properties of real patient anatomy as closely as possible. To this end, it is known to provide phantoms that include distinct internal components that represent different anatomical features. For example, US7255565B2 discloses a phantom that includes a body composed of a thermoplastic elastomer with embedded glass beads or marbles to mimic tumours, thrombus or calcifications.
While useful as a basic training tool, existing phantoms of this type have limited ability to accurately simulate the shape and ultrasound reflection properties of more complex anatomical features based on real world patient anatomy. Furthermore, existing techniques that are used to manufacture such phantoms mean that it is slow and costly to create new phantoms representing novel patient anatomy.
It would be desirable to provide methods of manufacturing phantoms that obviate or mitigate some or all of the above-described disadvantages.
Summary of the Invention
In accordance with a first aspect of the invention there is provided a method of manufacturing an anthropomorphic phantom for use as a medical ultrasonography training aid. The phantom comprises a plurality of components representing 5 anatomical features. The method comprises, for each component: generating a three-dimensional model of the component based on patient medical scan data; forming, using an additive manufacturing technique, a mould based on the three-dimensional model; selecting a material for the component with ultrasound reflection properties that correspond with the ultrasound reflection properties of the anatomical feature that the 10 component represents; and forming the component from the selected material using the mould. The method further comprises: assembling the plurality of components to form the phantom.
Optionally, the ultrasound reflection properties comprise at least one of: acoustic impedance, attenuation, or scattering.
Optionally, the selected material is a gel comprising mineral oil, styrene-ethylenebutylene-styrene (SEBS), and optionally low-density polyethylene (LDPE).
zo Optionally, selecting a material for the component further comprises selecting a material with a firmness that corresponds with the firmness of the anatomical feature that the component represents.
Optionally, selecting a material for the component comprises selecting an amount of 25 SEBS and/or LOPE in the gel.
Optionally, assembling the plurality of components to form the phantom comprises positioning each of the plurality of components within a casing in a position that corresponds with the position of the anatomical feature that the component represents.
Optionally, the casing comprises an open face that exposes the phantom to a user for performing a medical ultrasonography training procedure.
Optionally, the method further comprises: filling the casing with an interstitial material to cover the plurality of components.
Optionally, the interstitial material is a gel.
Optionally, assembling the plurality of components to form the phantom further comprises positioning a feedback component in a position corresponding to a target anatomical region at or immediately adjacent to a medical needle penetration site.
to Optionally, the feedback component is not penetrable by a medical needle.
Optionally, the feedback component is composed of an electrically conductive material arranged to form an electrical circuit when contacted by a medical needle.
Optionally, assembling the plurality of components to form the phantom further comprises positioning one or more sheets within the phantom to represent fascia.
Optionally, assembling the plurality of components to form the phantom further comprises positioning one or more portions of silicone tube within the phantom to 20 represent anatomical vessels.
Optionally, the mould is a positive mould and forming the component from the selected material using the mould comprises using the positive mould to form a negative mould of the component, and forming the component from the negative mould.
Optionally, forming the component from the selected material using the mould comprises heating the selected material to form a liquid, pouring the liquid into the negative mould, and allowing the material to solidify.
Optionally, the patient medical scan data is radiographic medical scan data.
Optionally, the radiographic medical scan data is computed tomography (CT) scan data.
Optionally, the additive manufacturing technique is a fused deposition modelling (FDM) or stereolithography (SLA) technique.
In accordance with a second aspect of the invention there is provided an 5 anthropomorphic phantom for use as a medical ultrasonography training aid. The phantom comprises a plurality of components representing anatomical features. The phantom is manufactured in accordance with the method of the first aspect.
Advantageously, embodiments of the invention provide methods of manufacturing phantoms that more closely simulate real world patient anatomy. The phantoms include separate components representing anatomical features, such as individual muscles or organs. The components are shaped and positioned based on medical scan data from a patient. Furthermore, the ultrasound reflection properties of each component are selected so that they correspond with the ultrasound reflection properties of the anatomical feature that the component represents. Advantageously, such phantoms can be particularly useful to train medical practitioners to perform ultrasonography procedures because the phantom can more realistically simulate complex patient anatomy including a range of anatomical features and tissue types.
Advantageously, the components are shaped using a mould manufactured using an additive manufacturing technique from patient medical scan data. Advantageously, this can improve the ease and precision with which phantoms can be produced. Furthermore, the use of patient medical scan data together with additive manufacturing techniques means that phantoms representing novel patient anatomy can be quickly and cost effectively produced.
Various further features and aspects of the invention are defined in the claims.
Brief Description of the Drawings
Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings where like parts are provided with corresponding reference numerals and in which: Figure la provides a schematic partial cut-away diagram showing an anthropomorphic phantom manufactured in accordance with certain embodiments of the invention; Figure lb provides a cross-sectional diagram of the side of the phantom of Figure la; Figure 2 shows a three-dimensional model of an anatomical region of a patient in accordance with certain embodiments of the invention; Figures 3a and 3b are simplified schematic diagrams showing the steps of a process 15 of creating a 3D mould of a component in accordance with certain embodiments of the invention; Figures 4a-4c are simplified schematic diagrams showing the steps of a process of forming a component for a phantom using a mould in accordance with certain 20 embodiments of the invention; Figure 5a and 5b are schematic diagrams depicting assembling a plurality of components to form a phantom in accordance with certain embodiments of the invention; Figure 6 is an ultrasound image of a phantom manufactured in accordance with certain embodiments of the invention; and Figure 7 provides a schematic diagram of a phantom manufactured in accordance with 30 certain embodiments of the invention.
Detailed Description
Figure la provides a schematic partial cut-away diagram showing an anthropomorphic phantom manufactured in accordance with certain embodiments of the invention. Figure lb provides a cross-sectional diagram of the side of the phantom of Figure 1 a.
The phantom 100 is used as a medical ultrasonography training aid to train medical practitioners to perform ultrasonography procedures such as diagnostic imaging or ultrasound guided interventions. The phantom 100 is manufactured using the techniques described herein.
The phantom 100 comprises a casing 101. The casing 101 is a vessel with an open face. The casing 101 encloses the components of the phantom 100. The casing 101 is typically composed of a resilient material such as metal or plastic. The open face allows a user to contact a surface of the phantom 100 with an ultrasonography probe during a medical ultrasonography training procedure. The open face represents a part of a patient where a medical ultrasonography procedure would be conducted.
The phantom 100 comprises a plurality of components that represent distinct anatomical features, including first component 102, second component 103 and third component 104. It will be understood that the first component 102 and second component 103 are shown schematically and can represent any suitable anatomical part such as a particular muscle or organ. The third component 104 is a layer positioned adjacent to the open face of the casing to represent a layer of skin.
The first component 102 and second component 103 are enclosed within an interstitial material 105. The interstitial material 105 covers the first component 102 and second component 103 such that they are suspended in it.
As described herein, the shapes of the first component 102 and second component 103 are formed from a mould that was produced using an additive manufacturing technique. The shape of the mould is based on a digital three-dimensional model created from patient medical scan data. The medical scan data can be obtained from a suitable radiographic technique such as computed tomography (CT).
The first component 102, second component 103 and third component 104 are each composed of a material with ultrasound reflection properties that correspond with the ultrasound reflection properties of the anatomical feature that the components represent. For example, if a component represents an organ, the component is composed of a material with ultrasound reflection properties that correspond with the ultrasound reflection properties of the particular organ.
The ultrasound reflection properties referred to herein comprise acoustic impedance, attenuation, and/or scattering. As will be understood, acoustic impedance refers to the resistance to the propagation of ultrasound waves through an imaging medium. Attenuation refers to the reduction of the amplitude of an ultrasound signal as a function of the distance through an imaging medium. Scattering refers to the tendency of an imaging medium to dissipate ultrasound energy in multiple directions.
In addition, in certain embodiments, the components are composed of a material with a firmness that corresponds with the firmness of the anatomical feature that the components represent. For example, the third component 104 can be composed of a material with a firmness that corresponds with the firmness of the skin.
The first component 102, second component 103 and third component 104 are composed of a gel comprising mineral oil and styrene-ethylene-butylene-styrene (SEBS). In certain embodiments, the gel further comprises low-density polyethylene (LDPE). In certain embodiments, the gel further comprises an ultrasound scattering agent such as talcum powder and/or a colouring agent such as a dye.
As described in more detail below, the ultrasound reflection properties and firmness of the components can be selected by varying the relative amounts of SEBS (and optionally LOPE and scattering agent) included in the gel. The appearance of the components can be selected by including a colouring agent.
In this way, the phantom 100 provides a realistic representation of part of a patient because components of the phantom 100 representing anatomical features are shaped based on patient medical scan data and their ultrasound reflection properties (and optionally also their firmness and appearance) are "tuned" to the anatomical feature that they represent.
The phantom 100 described and depicted with reference to Figures la and lb represents a simplified schematic anatomical region. It will be understood, however, that phantoms are typically produced to represent a complex part of a patient using multiple components representing, for example, bone, connective tissue (including fascia), muscle, organs, nerves, blood vessels, and pathological anatomical features such as tumours.
In certain embodiments, the phantom has one or more components composed of a non gel-based material such as a plastic, plaster, silicone, polyurethane or resin material.
A method of manufacturing an anthropomorphic phantom will now be described with reference to Figures 2-5. The method can be used to manufacture a phantom of a type described herein.
Figure 2 shows a three-dimensional model of an anatomical region of a patient in 20 accordance with certain embodiments of the invention. The model 200 is a digital model generated from patient medical scan data. The medical scan data can be obtained from a suitable radiographic technique such as computed tomography (CT).
The model 200 includes a plurality of components, each component representing a distinct anatomical feature. For example, the model 200 includes a first component 201 representing the pelvis bone, a second component 202 representing the iliopsoas muscle, a third component 203 representing the internal oblique muscle, a fourth component 204 representing the sartorius muscle, and a fifth component 205 representing the femoral artery. It will be understood that various suitable software tools can be used to generate and manipulate 3D models of the components.
The model 200 is used to create moulds for each of the components using an additive manufacturing technique. Figures 3a-3b provide an example of a process of creating a 3D mould of a component based on a suitable model.
Figures 3a and 3b are simplified schematic diagrams showing steps of a process of creating a 3D mould of a component in accordance with certain embodiments of the invention. The mould is a two-part negative mould. The mould can be used to form a component by pouring liquid material into it and allowing the material to solidify.
First, a three-dimensional digital model of a component is provided, for example using the process described with reference to Figure 2. The component represents a distinct anatomical feature. In the example described with reference to Figure 3a-3b, the 10 component represents the iliopsoas muscle.
The model is digitally split in half to generate a first sub-model corresponding to the first half of the component and a second sub-model corresponding to the second half of the component. As will be understood, for complex shaped components, the position of the split is chosen to make it easier to de-mould the components during use of the mould.
Next, the first and second sub-models are modified to include respective mould casings. Figure 3a shows the first sub-model including a mould casing 300 surrounding the first part 301 of the component. Figure 3b shows the second sub-model including a mould casing 302 surrounding the second part 303 of the component.
As shown in Figure 3a, the mould casing 300 surrounding the first part 301 comprises 25 walls 304 that enclose the first part 301, and a base 305 that supports the first part 301 and engages with the walls 304. The base 305 comprises keys 306a 306b 306c provided by recessed triangles.
Similarly, as shown in Figure 3b, the mould casing 302 surrounding the second part 30 303 comprises walls 307 that enclose the second part 303, and a base 308 that supports the second part 303 and engages with the walls 307. The base 308 comprises keys 309a 309b 309c provided by protruding triangles.
The keys provided in the respective bases 305 308 of the first and second mould casings 300 302 are shaped to engage with each other. It will be understood that other suitable shapes and configurations of keys can be provided.
Next, a two-part positive mould is formed by an additive manufacturing process. The first part of the two-part positive mould corresponds to the first sub-model (as depicted in Figure 3a) and the second part of the two-part positive mould corresponds to the second sub-model (as depicted in Figure 3b). In certain embodiments, the walls are manufactured as separate components so that they can be more easily removed from during use of the mould.
It will be understood that any suitable additive manufacturing technique can be used to manufacture the two-part positive mould. In certain embodiments, the additive manufacturing technique is a fused deposition modelling (FDM) or stereolithography 15 (SLA) technique.
Next, the two-part positive mould is used to manufacture a corresponding two-part negative mould. The first part of the positive mould is filled with a liquid material and the material is allowed to solidify. Typically, the material is silicone or polyurethane.
Once the material has solidified, the first part of the positive mould is removed, leaving a corresponding negative mould. The process is repeated for the second part of the positive mould to create a corresponding negative mould.
The two-part positive mould can then be discarded or reused to form further two-part negative moulds.
The process results in a two-part negative mould that can be used to form a component. As described above, the resulting two-part negative mould includes keys 30 that hold the parts of the mould together in use.
Advantageously, the above-described technique has several advantages compared with known techniques where a negative mould is created using an imprint made by a positive mould in a soft material such as wax. Techniques in accordance with embodiments of the invention require less user input, less material, less time, and produce a more consistent component. In particular, the walls of the mould casing can be sized to minimise unnecessary overuse of mould material, the technique avoids physical manipulation of soft material such as clay which can be time-consuming, the liquid mould material can be mixed and poured into the two parts of the mould simultaneously to save time, and the two-part positive mould can be reused to make further identical negative moulds.
The process described with reference to Figures 3a-31D is repeated to create moulds for a plurality of components of the phantom. It will be understood that in certain embodiments, other techniques can be used to create suitable moulds. For example, in certain embodiments a two-part negative mould can be directly formed by an additive manufacturing technique based on patient medical scan data.
Figures 4a-4c are simplified schematic diagrams showing a process of forming a 15 component using a two-part negative mould. The process is repeated for a plurality of components of a phantom, where each component represents a distinct anatomical feature within the phantom.
As shown in Figure 4a, the two-part negative mould comprises a first mould part 400 20 and a second mould part 401. The negative mould can be formed using the technique described with reference to Figures 3a-3b.
The first mould part 400 and second mould part 401 are connected by correspondingly shaped keys 402 403 provided on facing surfaces of the mould parts 400 401.
A suitable material for the component is selected. The material is selected so that the ultrasound reflection properties of the component correspond with the ultrasound reflection properties of the anatomical feature that the component represents. For example, if the component is a skeletal muscle, a material for the component is selected that has ultrasound reflection properties that match the ultrasound reflection properties of skeletal muscle. This means that the component provides a realistic simulation of the ultrasound response of skeletal muscle during an ultrasonography training procedure.
In certain embodiments, the material is also selected so that it has a firmness that corresponds with the firmness of the anatomical feature that the component represents. For example, if the component is a skeletal muscle, a material for the component is selected that has a firmness that matches the firmness of skeletal muscle. This means that the phantom behaves more realistically during manual palpation or when a user is performing a guided ultrasound procedure which involves inserting a medical needle into the phantom.
In certain embodiments, the material is also selected so that it has a colour that 10 corresponds with the colour of the anatomical feature that the component represents. For example, if the component is skin, the material is selected so that it has a colour that corresponds with a skin colour.
The material is a gel comprising mineral oil and styrene-ethylene-butylene-styrene (SEBS). In certain embodiments, the gel also comprises low-density polyethylene (LDPE). In certain embodiments, the gel also comprises a scattering agent and/or a colouring agent. Selecting the material involves selecting the relative amounts of mineral oil and SEBS (and optionally LDPE, scattering agent and/or pigment) to produce the desired material properties.
The mineral oil acts as the base to be plasticised into a gel by the SEBS. The mineral oil can be white mineral oil.
The SEBS acts as a plasticiser to turn the mineral oil into a gel. SEBS is a thermoplastic elastonner. A suitable SEBS material is Kraton G1650 M, sold by Kraton Polymers LLC (USA), which is a clear, linear triblock copolymer based on styrene and ethylene/butylene with a polystyrene content of 30%. The SEBS is used in fluffy crumb form.
The low density polyethylene (LDPE) is also plasticised by SEBS. The LDPE is used in powder form.
The scattering agent is used to replicate the ultrasonographic scatter seen in vivo. Various different materials can be used as scattering agents such as talcum powder, glass beads, flour or aluminium oxide. Talcum powder is particularly advantageous because it is widely available, affordable, and non-toxic.
The colouring agent is used to change the appearance of components of the phantom. 5 A range of oil-compatible pigments can be used. A suitable pigment is oil-based cosmetic foundation make-up.
Increasing the relative amount of LDPE increases the acoustic impedance and attenuation of the material. Increasing the relative amount of LDPE also increases the 10 firmness and reduces the flexibility of the material. Increasing the relative amount of SEBS increases the firmness of the material.
In one example, the selected material comprises mineral oil, 8% SEBS and 6% LDPE, where the amount of SEBS and LDPE is given as a percentage of the volume of mineral oil. Such a material has ultrasound reflection properties that correspond with those of muscle tissue.
First, the SEBS and mineral oil (and optionally LDPE) are mixed and heated to a temperature of approximately 130-150°C until they form a homogeneous fluid. At a 20 temperature of 150°C, the fluid is heated for approximately 40 minutes per litre of fluid.
Next, if being used, a scattering agent and colouring agent are added. The scattering agent and colouring agent are preferably added after the SEBS, mineral oil and LDPE are homogenised because they tend to settle towards the bottom of the container due to gravity. The scattering agent and colouring agent are mixed well, and the fluid continues to be heated for a period of time to allow mixing (for example for a further 20 minutes).
Next, the fluid is removed from the heat source and put in a vacuum chamber for 30 approximately 5 minutes at approximately -1 bar to reduce entrapped air bubbles.
As shown in Figure 4b, the fluid is then poured into the mould provided by the first mould part 400 and the second mould part 401 and allowed to cool and solidify into a gel.
As shown in Figure 4c, the first mould part 400 and second mould part 401 are removed from the component 404.
The process is repeated for further components of the phantom.
As described, in certain embodiments, the phantom can include additional components that are not produced in accordance with the process described with reference to Figures 4a-4c (for example, non gel-based components provided by hard plastic corresponding to bone).
Figure 5a and 5b are schematic diagrams depicting assembling a plurality of components to form a phantom 500 in accordance with certain embodiments of the invention.
In certain embodiments, the phantom 500 is assembled by hand. Alternatively, one or more steps of the assembly process can be fully or partly automated using a suitable technique.
First, a casing is provided (not shown). The casing is typically of a type described with reference to Figure 1 and is composed of a hard material such as plastic and arranged to enclose the components of the phantom 500. The casing has an open face which allows materials to be placed within it.
As described in more detail below, the components of the phantom 500 are positioned within the casing in positions that correspond with the positions of the anatomical features that they represent.
In this embodiment, the phantom 500 comprises a first component 501 representing the pelvis bone, a second component 502 representing the iliopsoas muscle, a third component 503 representing the internal oblique muscle, a fourth component 504 representing the sartorius muscle, and a fifth component 505 representing the femoral artery. In certain embodiments, as shown in Figure 5b, the phantom can include a sixth component 506 representing fascia.
The first component 501 representing the pelvis bone is positioned in the bottom of the casing in an anatomically correct position.
The fifth component 505 representing the femoral artery is positioned within the casing. When components representing anatomical vessels are provided (typically in the form of silicone tube), to help maintain their position within the casing, a stiff metal wire can be run through the vessels and bent as appropriate to give the vessels the correct anatomical path. The ends of the vessels typically either run up the wall of the casing and exit at the top, or through holes in the sides of the casing.
Interstitial material (typically a suitable gel) is poured into the casing until it reaches a level where the next component or components need to be located. The interstitial material is allowed to cool slightly so that it solidifies enough to allow components to be placed on it and maintain their position. This process is repeated until all of the components have been placed in their correct anatomical positions and the spaces between the components are filled with interstitial material After the interstitial material has set, the metal wires are pulled out from the anatomical vessels.
zo As shown in Figure 5b, in certain embodiments assembling the plurality of components to form the phantom 500 further comprises positioning one or more sheets within the phantom 500 to represent fascia. The sheets can be composed of silicone, HDPE, LDPE or PVC.
The assembled phantom is verified against the digital model that it represents to ensure the components are in the correct positions.
Figure 6 is an ultrasound image of a phantom manufactured in accordance with certain embodiments of the invention. The image is taken by placing an ultrasound probe in 30 contact with the phantom at an open face of the phantom casing.
As described herein, the phantom includes components representing anatomical features of a patient, the components having ultrasound reflection properties that correspond with the ultrasound reflection properties of the anatomical features that the components represent.
The components visible in the image include a sartorius muscle component 600, an 5 internal oblique muscle component 601, an iliacus muscle component 602, an anterior inferior iliac spine (AIIS) bone component 603, and an iliac fascia component 604.
Advantageously, as shown in Figure 6, the phantom provides a realistic simulation of an anatomical region of a patient. The phantom provides a tool for training medical 10 practitioners to perform ultrasound procedures without the presence of a patient.
Figure 7 provides a schematic view of a phantom manufactured in accordance with certain embodiments of the invention.
The phantom 700 is manufactured in accordance with the techniques described herein. The phantom 700 is used for training medical practitioners to perform ultrasound guided interventions that involve inserting needles into specific anatomical regions of a patient.
The phantom 700 comprises a spine and ribcage component 701, a first lung component 702, a second lung component 703, and a paravertebral space component 704.
As will be understood, the paravertebral space is an anatomical compartment adjacent 25 to the vertebral bodies of the spinal cord. The paravertebral space contains spinal nerves and is commonly used as an injection site for administering local anaesthetic.
In certain embodiments, the paravertebral space component 704 is provided by one or more portions of silicone tube which a user can inject fluid into during a training 30 procedure. In other embodiments, the paravertebral space component 704 is provided by interstitial gel.
The phantom 700 can be used to train medical practitioners to perform ultrasound guided administration of local anaesthetic within the paravertebral space. To provide additional feedback to a user, the phantom 700 includes a feedback component.
The feedback component is positioned at or immediately adjacent to a target anatomical region within the phantom 700. A target anatomical region is a region where a needle should, or should not, be inserted during a medical procedure.
In this embodiment, the feedback component is positioned within the paravertebral 10 space component 704, which is a target anatomical region that represents a region where a needle should be inserted during a medical procedure.
However, it will be understood that alternatively or additionally, feedback components could be positioned in either or both of the first and second lung components 702 703, 15 which are target anatomical regions where a needle should not be inserted during a medical procedure.
In certain embodiments, the feedback component is composed of a material that is not penetrable by a medical needle. In this way, the feedback component provides 20 physical feedback to a user as a needle makes contact with it.
Alternatively or additionally, in certain embodiments the feedback component comprises an electrically conductive material that is connected to an electrical circuit such that when a needle makes contact with the feedback component, the circuit is completed. The circuit can be connected to a power source and a light and/or buzzer so that the light and/or buzzer are activated when a needle makes contact with the feedback component.
In certain embodiments, the electrically conductive material is aluminium foil or electrically conductive paint. In certain embodiments, the electrically conductive material covers a target component of the phantom (such as the lungs or the paravertebral space) or is contained within a target component.
In certain embodiments, a power source and light and/or buzzer are provided as part of the phantom. For example, the power source and light and/or buzzer can be fixed to the phantom casing.
In certain embodiments, a phantom can comprise one, or more than one feedback component.
Advantageously, the feedback component provides real time feedback to a user as they insert a needle into a phantom.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. The invention is not restricted to the details of the foregoing embodiment(s).
The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations).
It will be appreciated that various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope being indicated by the following claims.