Site marker visible under multiple modalities

A site marker is provided that includes a generally hollow body defining a cavity. A deployment line within the site marker positions at least one marker element within the body portion. The deployment line has a first end that is fixedly secured to a first end of the body portion and a second end that is secured to a second end of the body portion. The deployment line is pre-biased so as to pull the first end of the body portion towards the second end of the body portion, and thereby expand the body portion.

FIELD OF THE INVENTION

The present invention relates generally to site markers for breast biopsy procedures. More specifically, the present invention relates to site markers that are visible under multiple modalities.

BACKGROUND OF THE INVENTION

In the diagnosis and treatment of breast cancer, it is often necessary to perform a biopsy to remove tissue samples from a suspicious mass. The suspicious mass is typically discovered during a preliminary examination involving visual examination, palpation, X-ray, magnetic resonance imaging (MRI), ultrasound imaging or other detection means.

When a suspicious mass is detected, a sample is taken by biopsy, and then tested to determine whether the mass is malignant or benign. This biopsy procedure can be performed by an open surgical technique, or through the use of a specialized biopsy instrument. To minimize surgical intrusion, a small specialized instrument such as a biopsy needle is inserted in the breast while the position of the needle is monitored using fluoroscopy, ultrasonic imaging, X-rays, MRI or other suitable imaging techniques.

In a relatively new procedure, referred to as stereotactic needle biopsy, the patient lies on a special biopsy table with her breast compressed between the plates of a mammography apparatus and two separate X-rays are taken from two different points of reference. A computer then calculates the exact position of the mass or lesion within the breast. The coordinates of the lesion are then programmed into a mechanical stereotactic apparatus which advances the biopsy needle into the lesion with precision. At least five biopsy samples are usually taken from locations around the lesion and one from the center of the lesion.

Regardless of the method or instrument used to perform the biopsy, subsequent examination of the surgical site may be necessary, either in a follow up examination or for treatment of a cancerous lesion. Treatment often includes a mastectomy, lumpectomy, radiation therapy, or chemotherapy procedure that requires the surgeon or radiologist to direct surgical or radiation treatment to the precise location of the lesion. Because this treatment might extend over days or weeks after the biopsy procedure, and the original features of the tissue may have been removed or altered by the biopsy, it is desirable to insert a site marker into the surgical cavity to serve as a landmark for future identification of the location of the lesion.

Known biopsy site markers have been found to have disadvantages in that the site markers are not visible under all available modalities. Moreover, because of this problem, when cancer is found at a biopsy site that has been previously marked with a site marker, due to the poor visibility of the biopsy site marker under ultrasound or other visualization modalities, the patient must undergo an additional procedure that places an additional device the biopsy site to enable the surgeon to find the biopsy site in subsequent procedures. One known technique has been to place a breast leasion localization wire at the biopsy site. The localization wire is typically placed at the biopsy site via mammography and/or ultrasound.

Accordingly, there is a need for site markers made from biocompatible materials that are visible under various modes of imaging to reduce the number of procedures that patients must undergo in detection and treatment of cancer.

SUMMARY OF THE INVENTION

A site marker is provided that includes a generally hollow body defining a cavity. The site marker is formed into a predeployment configuration whereby the site marker is compressed into a predetermined size and shape to as to be readily positionable within a deployment device. The site marker expands from the first predeployment position to a second post deployment configuration upon insertion into the body. A thread or deployment line (e.g., thread, filament, wire) is attached to and extends between a forward end and a rearward end of the body portion. At least one marker element with a through opening (e.g., ring, tube, helical shape) is included. Accordingly, the deployment line is received in the through opening such that the marker element may selectively slide along the deployment line. This limits migration of the marker element within a body. In another embodiment, a site marker is provided with a filament that may be used either alone or in addition to a deployment line to further hold the marker element in place at an end of the site marker. In yet another embodiment, a deployment line is a hollow tube, and a marker element is able to fit inside of the hollow deployment line.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1illustrates a perspective view of a human breast10being implanted with a site marker12according to an embodiment of the present invention. At a biopsy site14is a lesion16from which a tissue sample has been removed, resulting in a biopsy cavity18. One or more site markers12are implanted in the biopsy cavity18using a marker delivery system20, as shown inFIG. 1. In one embodiment, the marker delivery system20is slidably advanced through an inner lumen22of a biopsy device (not shown), which avoids the need to withdraw the biopsy device and thereafter insert the marker delivery system20. Delivering the site marker12in the biopsy cavity18without withdrawing the biopsy device reduces the amount of tissue damage and enables more accurate placement of the site marker12. The marker delivery system20illustrated inFIG. 1is exemplary only and it is understood that the site marker embodiments disclosed herein are suitable for use with other marker delivery systems.

FIGS. 2A-8Billustrate suitable exemplary site marker embodiments according to the present invention. In general, the site markers described herein are made from biocompatible materials such as, but not limited to, titanium, stainless steel, and platinum. These materials have appropriate densities for radiographic imaging, appropriate surface characteristics for ultrasonic imaging, and appropriate magnetic characteristics for magnetic resonance imaging. The site markers that will be described below are preferably made from titanium; however, it is understood that any suitable biocompatible material may be used.

Referring initially toFIGS. 2A and 2B, a site marker24includes a plurality of balls26sintered together to form a unitary body. The balls26, as shown, vary in size and are sintered together randomly such that there is no structured or predetermined equidistance between the centers of the balls26. In other embodiments, the size of the balls26may be generally uniform, or the balls26may be sintered together such that the centers of the balls26are aligned in a predetermined manner. As illustrated inFIGS. 2A and 2B, one embodiment of site marker24measures approximately 1.5 mm in diameter (FIG. 2B) and 3 mm in length (FIG. 2A). As those skilled in the art will appreciate, when the size and sintering pattern of the balls26are modified, the size, shape and dimensions of the site marker will also vary. The balls26may be constructed from any biocompatible material with suitable echogenic properties such as, but not limited to, titanium, stainless steel, or platinum.

FIGS. 3A and 3Billustrate another embodiment of the invention having irregularly shaped particles or bits28that are sintered together to form site marker30. The particles, as shown inFIGS. 3A and 3B, are exaggerated to illustrate the random shapes of the particles28. In application, however, the edges of the particles are sufficiently smooth so as to not damage any tissue. The particles can be substantially similar in size and shape, or they may vary as shown inFIGS. 3A and 3B. The particles28may be constructed from any biocompatible material with suitable echogenic properties such as, but not limited to, titanium, stainless steel, or platinum.

In another aspect of the invention, the particles28may be sufficiently small such that, when sintered together, the resultant site marker32appears to form a porous metal, as shown inFIGS. 4A and 4B.

FIG. 5shows another embodiment of a biopsy site marker34made from a continuous strand of wire36. To form the biopsy site marker34, the wire36is fed into a molding cavity (not shown). When the wire36reaches the back wall of the cavity, it folds over onto itself conforming to the shape of the molding cavity. The wire36is compressed into a mass that resembles a ball of yarn. Inherently, the size and shape of the site marker34is dependent upon the size and shape of the molding cavity. The wire36may be constructed from any biocompatible material with suitable echogenic properties such as, but not limited to, titanium, stainless steel, or platinum.

FIG. 6shows a thin-walled hollow site marker in the form of a capsule38having an open end40. A cap42is attached to the open end40by a weld44. The capsule38is designed to resonate at a predetermined ultrasound frequency. In the event that the capsule38needs to resonate at more than one frequency, a resonant beam46, as shown inFIG. 6A, can be attached to the inner surface wall of the cap42so that the beam resonance is transmitted through the wall of the capsule. The capsule38may be constructed from any biocompatible material with suitable echogenic properties such as, but not limited to, titanium, stainless steel, or platinum.

FIGS. 7 and 7Ashow site marker48,50in the form of a rod56,58having drilled holes52,54throughout the body of the rod. Site marker48ofFIG. 7Ais a solid rod, whereas site marker50ofFIG. 7is a hollow rod or tube. The holes in both rods48,50may be drilled in a random or in a predetermined pattern. The rod56,58may be constructed from any biocompatible material with suitable echogenic properties such as, but not limited to, titanium, stainless steel, or platinum.

FIGS. 8A and 8Billustrate another embodiment of a site marker60that includes ball or bits62of material that are visible under one or more imaging modalities, and dispersed in a block of material64that is different than the balls or bits62. The balls or bits62may be constructed of titanium, stainless steel or other suitable material that are visible under more than one imaging modalities. In addition, the balls or bits62of material may be contacting each other within the block64and may vary in size and shape. In one embodiment, the block of material64is a biocompatible material such as epoxy. In another embodiment, the block of material is constructed of a bioabsorbable material that is absorbed by the patient's body such that only the balls62remain at the biopsy site.

FIG. 9illustrates another embodiment of a site marker70that is made in accordance with the present invention. Site marker70is a unitary body made of biocompatible material or a combination of biocompatible materials that are visible under one or more imaging modalities. Marker70may be hollow or solid. According to one aspect of the invention, marker70further includes a plurality of depressions72formed on an outer surface74of marker70. Depressions72may be formed on surface74so as to be set a predetermined distances apart from one another or may be randomly formed on outer surface74. Depressions72may also be formed so as to have a variety of shapes. In one embodiment, depressions72have a parabola shape, with a length of at least about 0.25 mm.

In another embodiment,FIG. 10Adiscloses yet another alternative embodiment of a site marker80. Site marker80includes a generally hollow body portion82that is flanked by closed ends84,86. Positioned within body portion82is a smaller permanent marker88that is captured therein. However, permanent marker88need not be attached to body portion82in any way. Permanent marker is preferably constructed of a suitable material that will not biodegrade within the body and which may be viewed under multiple imaging modalities, such as Magnetic Resonance Imaging (MRI). Examples of suitable materials for permanent marker88include, but are not limited to, titanium, stainless steel, ceramic, carbon, nickel titanium, and glass.

In one embodiment, body portion82is constructed of a bioabsorbable material such as polyglycolic acid (PGA), polylactic acid (PLA), hydrogel, collegen-based material or any other suitable material. The bioabsorbable material may be woven into a flexible mesh that has openings formed therein that are sized so as to be smaller than permanent marker88such that permanent marker88cannot escape body portion82. After installation in a biopsy cavity, over a predetermined time period such as three weeks to six months, body portion82is absorbed by the body, such that only permanent marker88remains within the body at the biopsy cavity. Because permanent marker88is captured within body portion82prior to absorption thereof by the body, permanent marker88is restricted from migrating from within the biopsy cavity. Indeed, movement of permanent marker88is limited to the internal cavity defined by body portion82. This insures that permanent marker88remains within the biopsy cavity to permit follow-up imaging of the biopsy site.

In one embodiment, prior to deployment into the biopsy site by a suitable deployment mechanism, site marker80, and more specifically, body portion82is formed in a first pre-deployment configuration (as shown inFIG. 10B), whereby the site marker80is compressed into a predetermined size and shape so as to be readily positionable within the deployment device. In fact, site marker80may be positioned in the deployment device prior to shipping deployment device. Once site marker80exits the deployment device into the biopsy site, site marker80is released from its compressed first pre-deployment configuration and automatically expands into a second post-deployment configuration (shown inFIG. 10A), whereby at least a portion of the body portion82of the site marker80expands at least as much as the outside diameter of the deployment device to form a close cage that holds permanent marker88such that site marker80cannot migrate back into the deployment device.

In another embodiment, as shown inFIG. 10C, an outside surface87of body portion82is provided with one or more barbs89disposed thereon. The barbs89assist in adhering site marker80to internal walls of the biopsy cavity. Barbs89are configured so as to extend at a predetermined angle relative to outside surface87. In one specific embodiment, barbs89are configured to extend perpendicular to outside surface87. In another embodiment, barbs89are positioned at different angles relative to one another, including opposing one another.

In another embodiment, as shown inFIGS. 10D and 10E, body portion82′ of site marker80′ is manually expanded from a first pre-deployment configuration (FIG. 10D) into a second post-deployment configuration (FIG. 10E). In this embodiment, site marker80′ is provided with a thread81or deployment line (e.g., thread, filament, wire) that is attached to the forward end84′ of body portion82′. Thread81is held by a tie-wrap style clinch via the deployment device. Once the site marker80′ is deployed, the tie-wrap pulls on thread81which pops open body portion82′ to the second post-deployment device to a predetermined maximum size. Upon reaching the predetermined maximum size, the deployment device severs thread81, releasing site marker80′ into the biopsy site.

Another embodiment of a site marker90is shown inFIGS. 11A and 11B. Site marker90is formed as a solid beam defined by relatively planar top and bottom surfaces92and93. When site marker90is subjected to a predetermined ultrasound frequency, it resonates, thereby making it visible under various modalities.

In an alternative embodiment, as shown inFIG. 11B, site marker90′ may further include a flange96attached to an end portion98the site marker90to assist with deployment and/or positioning site marker90′ within the biopsy site.

In one embodiment, site marker90,90′ and flange96is constructed from titanium or other suitable material. In another embodiment, site marker90,90′ is constructed from a solid piece of material such that it has no sealed chambers or regions that contain gas or air.

In yet another site marker design, the site marker contains a plurality of solid glass beads that are fused together similar to the sintered site marker24described above in connection withFIGS. 2A and 2B. In one embodiment, the glass material has a specific acoustic impedance ratio in the range of 8.2-9.4. The glass balls are fused together such that there are no sealed chambers or regions that contain air or gas.

FIG. 12A-12Cdepict a site marker100that is constructed of a foam-like material. The foam-like material may be a carbon filled polymer or a glass filled polymer so as to be visible under multiple modalities. In addition, the foam-like material may contain therapeutic materials to deliver medication to the biopsy site. One exemplary material for construction of site marker100is a thrombin filled polymer. The foam-like material acts as a matrix for tissue ingrowth.

Site marker100expands from a first pre-deployment configuration (shown inFIG. 12B) to a second post-deployment configuration (shown inFIG. 12C). In the first pre-deployment configuration, site marker is substantially compressed in either length or width or both so as to be receivable within a suitable deployment device. The site marker may remain in the pre-deployment device for an extended period of time, such that it may be desirable to pre-load a deployment device with one or more of the site markers in the first pre-deployment configuration.

In one embodiment, the material may from which site marker100is constructed is a shape memory material that will spring into the second post deployment configuration upon release from a deployment device into a biopsy cavity. In accordance with this embodiment, the site marker is designed to have a predetermined shape and then compressed into the first pre-deployment configuration. The site marker is then retained in the first pre-deployment configuration and may be loaded into a deployment device. It should be noted that the site marker may be stored in the deployment device in the first pre-deployment configuration for an extended period of time.

Once released from the deployment device and into the biopsy cavity, the site marker automatically springs into the second post-deployment configuration having a predetermined size and shape such that the site marker is easily visible under various imaging modalities.

In another embodiment, site marker100is constructed of a temperature dependent material. In accordance with this embodiment, the site marker does not expand from the first pre-deployment configuration into the second post-deployment configuration until heat is applied to the site marker100. Deploying the site marker100into a biopsy cavity provides a sufficient level of heat generated from the body to enable site marker100to automatically expand into the second post-deployment configuration after deployment.

In another embodiment, shown inFIGS. 13A-13B, a site marker102having a marker head104and one or more appendages106attached thereto is disclosed. In this embodiment, the marker head104may be a permanent marker such that it will not become absorbed by the body after deployment. Alternatively, however, it is understood that marker head104may be a bioabsorbable marker that is absorbed by the body by a predetermined time.

In one embodiment, the appendages106attached to the marker head104are semi-rigid and constructed of a heat activated material that causes the appendages106to curl outwardly once received in the body (SeeFIG. 13B). These appendages106serve to contact the walls of a biopsy cavity to prevent the marker102from migrating outside of the biopsy cavity.

Alternatively, the appendages106may be constructed of a memory-shape material whereby the appendages106are preformed with curled, outwardly extending ends108. The appendages106are then compressed into a pre-deployment configuration, such as that shown inFIG. 13Ato enable the marker102to be received within and deployed from a suitable deployment device. Once the marker102is deployed, the appendages106resume its preformed configuration which enables the appendages106to engage the walls of a biopsy cavity to prevent the marker102from migrating.

In another embodiment, as shown inFIG. 13C, appendages106may include one or more barbs110that extend outwardly from appendages106. Barbs110may be angled relative to appendages106and may be arranged on both top and bottom surfaces of appendages106. WhileFIG. 13Cillustrates barbs110being angled in a first direction on a top surface of appendages106and a second direction on a bottom surface of appendages106, it is understood that barbs110be oriented on each surface of appendages106in multiple directions. Barbs110serve to aid in attaching marker102to the walls of a biopsy cavity.

FIGS. 13D and 13Eare still a further embodiment of a site marker112. In this embodiment, site marker112includes two marker heads114that are joined together by one or more appendages116. The appendages116may include barbs (not shown) and may deform after deployment to a bowed configuration (FIG. 13E) to engage the biopsy cavity and prevent migration.

In another embodiment of the present invention, shown inFIGS. 14A-14C, an expandable site marker120is disclosed. Site marker120is generally hollow, defining a passageway therethrough and is constructed of a stent-like, woven mesh material that acts as a matrix for tissue ingrowth. The site marker120expands from a first pre-deployment configuration (shown inFIG. 14B) to a second, larger post-deployment configuration (shown inFIG. 14C). In the first pre-deployment configuration, site marker is substantially compressed in either length or width or both so as to be receivable within a suitable deployment device. The site marker120may remain in the pre-deployment device for an extended period of time, such that it may be desirable to pre-load a deployment device with one or more of the site markers120in the first pre-deployment configuration.

In one embodiment, the material may from which site marker120is constructed is a shape memory material that will spring into the second post deployment configuration upon release from a deployment device into a biopsy cavity. In accordance with this embodiment, the site marker120is designed to have a predetermined shape and then compressed into the first pre-deployment configuration. The site marker120is then retained in the first pre-deployment configuration and may be loaded into a deployment device. It should be noted that the site marker120may be stored in the deployment device in the first pre-deployment configuration for an extended period of time.

Once released from the deployment device and into the biopsy cavity, the site marker120automatically springs into the second post-deployment configuration having a predetermined size and shape such that the site marker120is easily visible under various imaging modalities.

In another embodiment, site marker120is constructed of a temperature dependent material. In accordance with this embodiment, the site marker120does not expand from the first pre-deployment configuration into the second post-deployment configuration until heat is applied to the site marker120. However, deploying the site marker120into a biopsy cavity provides a sufficient level of heat generated from the body to enable site marker120to automatically expand into the second post-deployment configuration after deployment.

Yet another embodiment of a site marker122, is shown inFIG. 15A. When site marker122is in a deployed configuration, as shown inFIG. 15A, it has a tetrahedron shell defined by external spines or ribs124that are pre-biased so as to form the tetrahedron shape. The spines124are connected together by a woven web material that permits tissue ingrowth to create the tetrahedron shell In one embodiment, tetrahedron shell is bioabsorbable such that after a predetermined time, the shell is completely absorbed by the body.

Contained within the tetrahedron shell is a marker126that is visible under one or more modalities. By having the marker126contained within the shell, the marker126is prevented from migrating. Indeed, the marker126may only move within the shell. In one embodiment, marker126is a permanent marker that will not become absorbed by the body. Alternatively, marker126may be a non-permanent marker that remains within the body for a predetermined length of time.

In an alternative embodiment, site marker122′ may be formed to have a double tetrahedron shell as shown inFIG. 15B. The double tetrahedron site marker122′ design is similar to the single tetrahedron site marker122in that it also is defined by external spines124′ that are pre-biased into the deployed configuration, as shown inFIG. 15B.

Both site marker122and122′ may be compressed into a first pre-deployment configuration, such as that shown inFIG. 15C. In this configuration, site markers122and122′ are substantially compressed in either length or width or both so as to be receivable within a suitable deployment device. The site markers122and122′ may remain in the pre-deployment device for an extended period of time, such that it may be desirable to pre-load a deployment device with one or more of the site markers122or122′ in the first pre-deployment configuration.

Once deployed by a suitable deployment device or released from the first, pre-deployed configuration, the pre-biased spines124,124′ of site markers122and122′ automatically return to site markers122and122′ to the deployed configurations shown inFIGS. 15A and 15B.

Yet another embodiment of a site marker128is shown inFIG. 15D. In this embodiment, a tube130that is formed of a mesh-like material is provided. Internal spines132, including base spines133, are positioned within tube130that are pre-biased to form a tetrahedron shell within tube130when in a deployed configuration. A marker134is positioned within the tetrahedron shell such that the marker is prevented from undesirable migration within the biopsy cavity.

In yet another alternative embodiment, base spines133are eliminated such that the remaining spines132within tube130are biased to form capped ends when the site marker128is in a deployed configuration.

To deploy the embodiments described in connection withFIG. 15D, the site marker128must be compressed into suitable size and shape to enable it to be received, stored and translated within a deployment device. Once the site marker128is deployed from the device, the pre-biased internal spines132and133, will automatically return the site marker128into the deployed configuration.

FIG. 16Aillustrates a partial cross sectional view of another embodiment of a site marker200that is similar to the embodiment shown inFIG. 10E. Site marker200includes a body portion202, which is shown in a post-deployment configuration. In this embodiment, site marker200is provided with a thread203or deployment line (e.g., thread, filament, wire) that is attached to and extends between a forward end204and a rearward end206of body portion202. Body portion202of site marker200is manually expanded from a first pre-deployment configuration (i.e.,FIG. 10D) into the second post-deployment configuration by thread203or deployment line. More specifically, thread203is pre-biased to spring forward and rearward ends204,206away from on another. A permanent marker208is positioned within body portion202and need not be attached to body portion202in any way. Instead, marker208may float freely within body portion202.

In yet another embodiment of a site marker210, as shown inFIG. 16B, a body portion212has at least one marker214that is held in place by deployment line216. Marker214, which may be a permanent marker that does not break down and become absorbed by the body for a predetermined time period, includes a through hole218. Accordingly, deployment line216is received in through hole218such that marker214may selectively slide along deployment line216. While marker214is shown as having a donut shape, it is understood that any body with a through hole able to accommodate the deployment line216such as, but not limited to, a ring, helical shape or tube that is able to slide along deployment line216without departing from the invention. In one embodiment, after installation in a biopsy cavity, over a predetermined time period such as three weeks to six months, body portion212is absorbed by the body, such that only marker214remains within the body at the biopsy cavity, and is visible under one or more modalities.

As mentioned above, marker214may be a permanent marker that is not absorbed by the body. Alternatively, marker214may be a semi-permanent marker that absorbs slower than body portion212. Because the movement of marker214is restricted by deployment line216prior to absorption thereof by the body, marker214is restricted from migrating from within the biopsy cavity. Indeed, movement of marker214is limited along the deployment line216. This insures that marker214remains within the biopsy cavity to permit follow-up imaging of the biopsy site.

In yet another alternative embodiment, a site marker220, as shown inFIG. 16C, includes a body portion222and at least one marker element224. Similar to the embodiment depicted inFIG. 16B, marker element224includes a through hole226that receives a deployment line225. In the embodiment shown, marker element224has an elongated profile, similar to a tube. However, it is understood that other shapes of marker224may be utilized. Marker element224may be at least partially retained by a filament228, where filament228is bonded to an end of body portion222. In one embodiment, filament228forms a loop around a portion of marker element224, to hold marker224in position within body portion222in addition to deployment line225.

After installation in a biopsy cavity, over a predetermined time period such as three weeks to six months, body portion222is absorbed by the body, such that only marker224remains within the body at the biopsy cavity. Because marker224is restricted along deployment line225, and is further constrained by filament228, marker224is restricted from migrating from within the biopsy cavity. Indeed, movement of marker224is limited along the deployment line225and is further constrained by filament228. This insures that marker224remains within the biopsy cavity to permit follow-up imaging of the biopsy site.

Yet another embodiment of a site marker230is shown inFIG. 16D. Site marker230includes a body portion232and at least one marker element234. In this embodiment, marker element234is restrained only by filament236. Once site marker230exits a deployment device into the biopsy site, site marker230is released from a pre-biased and compressed first pre-deployment configuration and automatically expands into a second post-deployment configuration (shown inFIG. 16D). Because marker234is restricted by filament236, marker234is restricted from migrating from within the biopsy cavity. Indeed, movement of marker234is limited along filament236. This insures that marker234remains within the biopsy cavity to permit follow-up imaging of the biopsy site.

In yet another embodiment of a site marker240, as shown inFIG. 16E, includes a body portion242that has a hollow deployment line244. Deployment line244, which is shown in cross sectional view, is designed so as to be able to accommodate at least one marker246. Marker246is constructed such that it has a smaller outside periphery than the inner circumference of hollow deployment line244. Marker246is able to selectively slide inside of hollow deployment line244. Because the movement of marker246is restricted by hollow deployment line244prior to absorption thereof by the body, marker246is restricted from migrating from within the biopsy cavity. Indeed, movement of marker246is limited along hollow deployment line244. This insures that marker246remains within the biopsy cavity to permit follow-up imaging of the biopsy site.

While the present invention has been particularly shown and described with reference to the foregoing preferred embodiments, it should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention embodiments within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. The foregoing embodiment is illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.