Systems and methods for locating markers within the body

Abstract

A probe and related systems and methods for locating a marker implanted in a patient's body are provided. The probe includes an antenna assembly adjacent to its distal end, the antenna assembly including a ceramic base, the ceramic base including a flat distal surface, and four proximal surfaces extending at a certain angle relative to the longitudinal axis of the probe to define a generally pyramidal shape. The base includes an antenna element on the proximal surface, and radial grooves between adjacent side surfaces to substantially isolate the antenna elements from each other. A controller is connected to the antenna element for transmitting a signal into the patient's body and receiving a reflected signal reflected from a marker implanted in the patient's body to identify and / or locate the marker.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 871,059, filed on July 5, 2019, entitled “Systems and Methods for Localizing Markers within a Body,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to systems and methods for identifying and / or locating markers, including markers implanted within a patient's body, for example, during a surgical procedure or other procedure, such as during a tumor resection procedure. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] The written disclosure herein describes non-limiting and non-exhaustive illustrative embodiments. Reference is made to certain such illustrative embodiments depicted in the accompanying drawings, in which:

[0005] Figure 1 An exemplary embodiment of a system for delivering and locating markers within a patient's body is shown, the system comprising a probe and a delivery device for implanting one or more markers within the patient's body.

[0006] Figure 2 It is a depiction Figure 1 A block diagram of exemplary components of a probe.

[0007] FIG. 3A to FIG. 3C are perspective, side, and end views, respectively, of an exemplary probe that may be included in Figure 1 to Figure 2 In the system shown in .

[0008] FIG. 4A to FIG. 4C Can be included in Figure 3A and Figure 3B Perspective, side, and bottom views of an exemplary antenna assembly in a probe.

[0009] Figure 5A and Figure 5B 2 are a top view and a side end view, respectively, of an exemplary embodiment of a marker for implantation in a patient's body.

[0010] Figure 6 Can be included in Figure 5A and Figure 5B An exemplary embodiment of a schematic diagram of a circuit in the markings.

[0011] Fig. 7A and Figure 7B Yes Description Figure 6A schematic diagram of the operation of the switch of the circuit.

[0012] Fig. 8A and 8B is a side view of a breast showing a delivery device for delivering a marker into tissue within the breast.

[0013] Fig. 9 is a side view of an exemplary embodiment of a probe for locating a marker implanted in a breast. DETAILED DESCRIPTION

[0014] Prior to a biopsy procedure or surgical procedure to remove a lesion within the breast (e.g., during a lumpectomy procedure), the location of the lesion must be identified. For example, mammography or ultrasound imaging can be used to identify and / or confirm the location of the lesion prior to the procedure. The surgeon can use the resulting images during the procedure to identify the location of the lesion and guide the surgeon to approach and / or remove the lesion, such as during a dissection. However, such images are typically two-dimensional and therefore provide only limited guidance for locating the lesion because the breast and any lesion to be removed are three-dimensional structures. Furthermore, such images can provide only limited guidance in determining an appropriate boundary zone around the lesion, i.e., defining a desired sample volume to be removed.

[0015] To facilitate positioning, immediately prior to the procedure, a wire may be inserted into the breast, such as via a needle, so that the tip of the wire is positioned at the location of the lesion. Once the wire is positioned, it may be secured in place, such as with a bandage or tape applied to the patient's skin where the wire emerges from the breast. With the wire placed and secured in place, the patient may undergo surgery, such as a biopsy or tumor resection.

[0016] One problem with using a wire for positioning is that the wire may move between the time of placement and the time of the surgical procedure. For example, if the wire is not adequately secured, the wire may move relative to the tract used to access the lesion, so the tip may incorrectly indicate the location of the lesion. If this happens, when the location is accessed and tissue is removed, the lesion may not be completely removed and / or healthy tissue may be removed unnecessarily. In addition, during the procedure, the surgeon may only estimate the location of the wire tip and the lesion, for example based on a mammogram or other image obtained during wire placement, and may perform the dissection without any further guidance. Again, since such images are two-dimensional, they can provide limited guidance to locate the lesion being treated or removed.

[0017] Alternatively, it has been proposed to place radioactive seeds during the procedure to provide localization. For example, a needle may be introduced through the breast into the lesion, and then the seeds deployed from the needle. The needle may be withdrawn, and mammography may be used to confirm the location of the seeds. During a subsequent surgical procedure, a handheld gamma probe may be placed over the breast to identify the location covered with the seeds. An incision may be made, and the probe may be used to guide the removal of the seeds and lesion.

[0018] Because the particles are delivered through a needle that is immediately removed, there is a risk that the particles may migrate within the patient's body between the time of placement and the time of the surgical procedure. Thus, similar to the use of localization wires, the particles may not accurately identify the location of the lesion, particularly since there is no external method to stabilize the particles once placed. Furthermore, such gamma probes may not provide the desired accuracy in identifying the location of the particles (e.g., in three dimensions), and therefore may only provide limited guidance in locating the lesion.

[0019] Therefore, devices and methods for locating lesions or other tissue structures prior to and / or during a surgical, diagnostic, or other medical procedure would be useful.

[0020] The present disclosure relates to systems and methods for identifying and / or locating markers implanted within a patient's body, for example, during a surgical procedure or other procedure, such as during a tumor resection procedure.

[0021] According to one embodiment, a probe for locating a marker within a patient's body is provided, the probe comprising: a first member or shell comprising a proximal end, a distal end configured to be placed adjacent to the patient's body, and a longitudinal axis extending between the proximal end and the distal end; an antenna assembly adjacent to the distal end, the antenna assembly comprising a base comprising a flat distal surface extending substantially perpendicular to the longitudinal axis, and a plurality of proximal surfaces extending at an angle relative to the longitudinal axis, each proximal surface comprising an antenna element, thereby providing a plurality of antenna elements; and a controller connected to the antenna elements for transmitting a transmit signal into the patient's body and receiving a reflected signal reflected from a marker within the patient's body to identify or locate the marker.

[0022] According to another embodiment, a probe for locating a marker in a patient's body is provided, the probe comprising: a first member or shell including a proximal end, a distal end configured to be placed adjacent to the patient's body, and a longitudinal axis extending between the proximal end and the distal end; an antenna assembly adjacent to the distal end, the antenna assembly comprising a base including a flat distal surface extending substantially perpendicular to the longitudinal axis, four proximal surfaces extending at an angle relative to the longitudinal axis to define a generally pyramidal shape, antenna elements on the proximal surfaces, and radial grooves between adjacent side surfaces to substantially isolate the antenna elements from each other; and a controller connected to the antenna elements for causing one or more of the antenna elements to transmit signals into the patient's body and for receiving, via one or more of the antenna elements, reflected signals reflected from a marker implanted in the patient's body, the controller processing the reflected signals to identify or locate the marker.

[0023] According to another embodiment, a system for identifying and locating a marker in a patient's body is provided, the system comprising: a delivery device for delivering the marker into the patient's body; an antenna probe comprising a proximal end, a distal end configured to be placed adjacent to the patient's body, and a longitudinal axis extending between the proximal end and the distal end, and an antenna assembly adjacent to the distal end, the antenna assembly comprising a base comprising a flat distal surface extending substantially perpendicular to the longitudinal axis, and a plurality of proximal surfaces extending at an angle relative to the longitudinal axis, each proximal surface comprising an antenna element, thereby providing a plurality of antenna elements; and a controller connected to the antenna elements for emitting a transmission signal into the patient's body and receiving a reflection signal reflected from a marker in the patient's body to identify or locate the marker.

[0024] According to another embodiment, a method for locating a marker within a body is provided, the method comprising: placing a distal end of a probe against tissue, the probe comprising an antenna assembly adjacent to the distal end, the antenna assembly comprising a base, the base comprising a flat distal surface placed adjacent to the tissue, and a plurality of proximal surfaces extending at an angle relative to a longitudinal axis of the probe; transmitting a transmit signal into the body via one or more transmit antenna elements on one or more of the proximal surfaces; receiving a receive signal reflected from the marker via one or more receive antenna elements on one or more of the proximal surfaces; and identifying the marker based at least in part on the receive signals.

[0025] Other aspects and features of the present disclosure will become apparent from the following description considered in conjunction with the accompanying drawings.

[0026] In the following description, numerous details are set forth in order to provide a more comprehensive description of the system. However, it will be apparent to those skilled in the art having the benefit of this disclosure that the disclosed system can be practiced without these specific details. In other instances, well-known features are not described in detail to avoid unnecessarily obscuring the system.

[0027] Go to the attached picture, Figures 1 to 4C An exemplary embodiment of a system 10 is shown for locating a target tissue region within a patient's body, for example, for identifying and / or locating one or more markers (e.g., such as a tumor, lesion, or other tissue structure) implanted within or near the target tissue region. Fig. 9 As shown in FIG. 4 , a marker 40 is implanted in a breast 90. Figure 1 As shown in , the system 10 may include a delivery device 60 carrying one or more targets, tags, or markers (a marker 40 is shown); a probe 20 for detecting and / or locating the marker 40, for example using an ultra-wideband radar; and a controller and / or display unit 38 connected to the probe 20, for example using one or more cables 36, which is generally similar to the embodiments described in U.S. Publication No. 2011 / 0021888, U.S. Publication No. 2014 / 0309522, U.S. Publication No. 2016 / 0354177, and U.S. Publication No. 2017 / 0319102, the entire disclosures of which are expressly incorporated herein by reference.

[0028] The probe 20 is a portable device (e.g., an elongated handheld device) having electromagnetic signal transmission and reception capabilities, the device including a first end or proximal end 22 that can be grasped by a user, for example, and a second end or distal end 24 that is intended to be placed against or adjacent to tissue (e.g., the patient's skin or underlying tissue) so as to define a longitudinal axis 25 therebetween. Generally, the probe 20 includes one or more antennas, for example, mounted or carried on an antenna assembly 30, such as, for example, FIG. 4A to FIG. 4C As shown in FIG. 1 , the antenna assembly includes one or more transmitting antennas 32T and receiving antennas 32R on a base 32, as further described below. In addition, the probe 20 includes an optical transmitter, such as a plurality of optical fibers 28 ( Figure 3C ), the light emitter is configured to emit light pulses 28a into tissue contacted by the distal end 24, for example, generally along the longitudinal axis 25 into breast tissue 90, as shown in FIG. Fig. 9 The optical fiber 28 can be connected to the optical fiber 28 by, for example, a connector 29 ( Fig. 9 ) is coupled to a light source (not shown) such that light from the light source passes through the optical fiber 28 at the distal end 24 away from the probe 20.

[0029] In an exemplary embodiment, the light source is an infrared light source, which is capable of delivering near infrared light having a wavelength between, for example, eight hundred nanometers and nine hundred and fifty nanometers (800nm-950nm). Optionally, if desired, the optical fiber 28 may include one or more lenses, filters, and the like (not shown), such as to focus the light emitted by the probe 20 in a desired manner (e.g., in a relatively narrow beam extending substantially parallel to the longitudinal axis 25, in a beam at a wider angle, etc.). Alternatively, one or more light sources (e.g., IR LEDs) may be provided on the distal end 24 instead of the optical fiber 28 to deliver the light pulses 28a.

[0030] The probe 20 may include a processor and / or display unit 38 within the probe housing 21 that includes one or more circuits, signal generators, gates, and the like (not shown) as needed to generate signals transmitted by the transmit antenna(s) 32T and / or process signals received from the receive antenna(s) 32R. The components of the processor may include discrete components, solid-state devices, programmable devices, software components, etc., as desired.

[0031] Figure 2 is a block diagram showing exemplary components of a controller for probe 20 (although alternatively, some of these components may be located in Figure 1 In the example shown, the probe 20 may include a signal generator 20a, an amplifier 20b, an analog-to-digital (A / D) converter 20c, and a digital signal processor (DSP) 20d. The signal generator 20a (e.g., a reference oscillator) generates an oscillating signal (such as a square wave signal, a triangle wave signal, or a sine wave signal).

[0032] For example, the probe 20 may include an impulse generator (e.g., a pulse generator and / or a pseudo-noise generator (not shown)) coupled to a transmit antenna to generate a transmit signal and an impulse receiver for receiving a signal detected by a receive antenna. The probe 20 may include a microcontroller and a range gate control that alternately activates the impulse generator and the impulse receiver to transmit electromagnetic pulses, waves, or other signals via the transmit antenna, and then receives any reflected electromagnetic signals via the receive antenna, for example, similar to other embodiments herein. Exemplary signals that may be used include, for example, microwaves, radio waves (such as microburst radar signals) in the ultra-low bandwidth region.

[0033] exist Figure 2In the example shown in , a square wave signal can be sent from the signal generator 20a to the (multiple) transmit antennas 32T of the antenna assembly 30 of the probe 20. When the square wave signal passes through the (multiple) transmit antennas 32T, the (multiple) transmit antennas 32T can act as a bandpass filter ("BPF") and convert the square wave signal into a series of pulses or other transmit signals 34T. Therefore, the transmit signal 34T ( Fig. 9 ) may include a series of pulses. Alternatively, the probe 20 may be configured to transmit a continuous wave signal, similar to the embodiments described in the disclosure incorporated herein by reference, for example.

[0034] The transmission signal 34T can be transmitted into the tissue and reflected from the marker 40 (eg, Fig. 9 Once the transmitted signal 34T is reflected from the marker 40, the reflected signal (i.e., the received signal 34R) includes a series of decaying pulses ( Figure 2 ).

[0035] The receiving antenna(s) 32R of the antenna assembly 30 of the probe 20 may receive the receiving signal 34R ( Figure 6 ) (e.g., a series of attenuated pulses), these received signals can be input into amplifier 20b to amplify the gain of the pulses. The output of amplifier 20b can be input into A / D converter 20c to convert the amplified analog signal into a digital signal. The digital signal output from A / D converter 20c can be input into DSP 20d for further processing. DSP 20d can perform many processing functions, including but not limited to: calculating the time difference from the time when transmit signal 34T is sent to the time when receive signal 34R is received, determining the distance from the distal end 24 of probe 20 to marker 40, determining the position of marker 40 relative to the distal end 24 of probe 20, measuring the amplitude of receive signal 34R, and / or determining the direction of marker 40 relative to the distal end 24 of probe 20, for example as described in the disclosure incorporated herein by reference.

[0036] The probe 20 may be coupled to a display 38a of a display unit 38, for example, via a cable 36, for displaying information to a user of the probe 20, such as spatial or image data obtained via antenna 32R and / or other outputs from the DSP 20d. Optionally, the probe 20 may include other features or components, such as one or more user interfaces, memories, transmitters, receivers, connectors, cables, power supplies, or the like (not shown). For example, the probe 20 may include one or more batteries or other internal power sources for operating the components of the probe 20. Alternatively, the probe 20 may include a cable (such as one of the cables 36) that may be coupled to an external power source (e.g., a standard AC power source) for operating the components of the probe 20.

[0037] like Figure 1 and Fig. 9 As shown in FIG. 1 , the internal components of the probe 20 (e.g., FIG. 3A to FIG. 4C ) can be disposed in an outer housing or cover 21 so that the probe 20 is self-contained. For example, the cover 21 can be relatively small and portable, such as so that the entire probe 20 can be held in the hand of a user. Optionally, a portion of the probe 20 can be disposable, such as a portion adjacent to the distal end 24, or if necessary, a disposable cover, sleeve, etc. (not shown) can be provided so that at least the proximal portion of the probe 20 can be reused. Alternatively, the entire probe 20 can be a disposable, single-use device, and the display unit 38 can be used during multiple procedures by connecting a new probe 20 to the display unit 38, which can be kept outside the surgical area, but remain accessible and / or visible as needed. Additional information about the construction and / or operation of the probe 20 can be found in the disclosures incorporated herein by reference elsewhere.

[0038] Go to FIG. 3A to FIG. 3C , illustrates exemplary internal components of the probe 20 (after removal of the outer housing 21), including, for example, an inner sleeve or housing 26 carrying the antenna assembly 30, and optionally a shield 37 at or within the distal end 26b thereof.

[0039] Additional references FIG. 4A to FIG. 4C, the antenna assembly 30 includes a base 32, which includes a substantially flat distal surface 32a (the substantially flat distal surface extends, for example, perpendicular to the axis 25), and a plurality of flat proximal surfaces 32b including antenna elements 32T, 32R. The distal surface 32a can be located at the most distal position of the distal end 24 of the probe 20, for example so that the distal surface 32a can be placed directly against the tissue (for example, covered with a film or covering to prevent fluid from entering the probe and / or other contamination). The base 32 can be formed of, for example, a ceramic and / or other non-conductive material having desired dielectric properties. For example, the base 32 can be formed of a material having a dielectric constant (permittivity) similar to the type of tissue with which the probe is intended to be used (for example, a dielectric constant similar to human breast tissue, skin, muscle, bone, fat, or other tissue). Thus, the base 32 material may include a dielectric constant ranging from about 1 to about 100, such as about 1-14 for embodiments intended for use with fat, about 5-8 for embodiments intended for use with breast tissue, about 60-70 for embodiments intended for use with muscle, about 70-80 for embodiments intended for use with skin, and about 6-25 for embodiments intended for use with bone.

[0040] exist Figure 4A and Figure 4B In the embodiment shown in , the base 32 includes four flat proximal surfaces 32b, such that the plane of each proximal surface 32b defines an acute angle θ with the axis 25, for example, between about thirty and sixty degrees (30°-60°), and the proximal surfaces 32b are offset from each other by ninety degrees around the axis 25, such that the proximal surfaces 32b define a generally pyramidal shape. Alternatively, the proximal surface may have a non-flat shape, such as a convex or concave surface (not shown) that tapers from the distal surface to the proximal end (not shown) of the base.

[0041] In this configuration, the antenna elements may include a pair of transmit antennas 32T and a pair of receive antennas 32R arranged in a butterfly configuration on the proximal surface 32b of the base 32, for example, the transmit antenna 32T is offset from the receive antenna 32R by ninety degrees (90°) to define a Maltese cross antenna. Each of the antenna elements 32T, 32R may be formed separately and then attached to the corresponding proximal surface 32b, or may be deposited directly onto the proximal surface 32b. In an exemplary embodiment, the antenna elements 32T, 32R may be formed of a silver film or other material deposited on the proximal surface 32b of the base 32.

[0042] A circuit structure 35 (e.g., a printed circuit board, a flexible circuit, etc.) may be coupled to the antenna 32T, 32R, for example comprising a PCB on which one or more transformers and / or connectors (not shown) are disposed, which are coupled to the corresponding antenna elements 32T, 32R via appropriate leads 35a. Figure 3A and Figure 3B As shown in , a coaxial cable or other lead 35b can be connected to a connector on the PCB to allow the antenna elements 32T, 32R to be connected to other components of the system, for example so that the antenna element 32T transmits signals to other components of the system 10 and / or communicates received signals, which is similar to other embodiments described herein.

[0043] like FIG. 4A to FIG. 4C As shown in , the base 32 also includes a plurality of radial grooves 33, such as grooves 33 between adjacent flat surfaces 32b. The grooves 33 can extend axially from the distal surface 32a to the proximal surface 32b to substantially isolate the antenna elements 32T, 32R from each other through the air within the grooves 33, which can increase sensitivity, reduce crosstalk and / or other noise, etc. Alternatively, the grooves 33 can be filled with other insulating materials (e.g., foam and the like (not shown)), which can have a desired relatively low dielectric constant to substantially isolate the antenna elements 32T, 32R from each other. In addition, as Figure 3C As shown in , the optical fiber 28 can be positioned within one or more of the grooves 33, for example, to deliver light pulses beyond the distal surface 32a of the base 32, as described elsewhere herein.

[0044] Alternatively, if Figure 3A and Figure 3B As shown in , the base 32 can be mounted within a shield 37, which in turn can be coupled to the distal end 26b of the inner housing 26 (and / or the distal end 24 of the outer housing 21), for example, by one or more of adhesive bonding, sonic welding, fusing, mating connectors (not shown), etc. For example, the shield 37 can include an annular inner insulating layer, such as formed by a collar of nylon or other polymeric material, surrounded by a relatively thin outer shield (not shown), such as formed by copper or other material to provide Faraday shielding. In an exemplary embodiment, a layer of copper tape can be wrapped around the inner shield and the ends are fixed together. Alternatively, the outer shield can be a sleeve of shield material, and the inner shield can be inserted and attached to the sleeve, such as by adhesive bonding, interference fit, etc.

[0045] The shield 37 may have a length (i.e., along the axis 25) that is significantly longer than the thickness of the base 32 (i.e., the distance from the distal surface 32a of the base 32 to the proximal end along the axis 25). For example, the inner shield may include an annular recess (not shown) into which the base 32 may be inserted and attached, for example, by interference fit, bonding with an adhesive, etc. The distal surface 32a of the base 32 may be substantially flush with the distal end of the shield 37 so that the distal surface 32a may contact tissue during use, as described elsewhere herein. Optionally, a Mylar film or other relatively thin layer of material (not shown) may be provided on the distal surface 32a of the base 32 and / or the shield 37, for example to prevent fluid or other materials from entering the tip, reduce contamination, and / or otherwise protect the tip of the probe 20.

[0046] Continue to refer Figure 4A and Figure 4B , the proximal surface 32b of the base 32 can be exposed to an air region within the shield 37. Due to the low dielectric constant of air (e.g., close to one (1)), the air provides a dielectric or impedance mismatch with the material of the base, so that the transmission from the transmit antenna 32T is focused distally, i.e., toward the tissue contacted by the base 32. In the case where the material of the base 32 is selected to substantially match the dielectric constant of the tissue, the transmission depth into the tissue can be enhanced. The air behind the base 32 can minimize the lost energy that would otherwise be emitted by the transmit antenna 32T away from the tissue. The air behind the base 32 within the shield 37 can also minimize crosstalk, noise and / or can enhance the operation of the probe 20.

[0047] Additionally, given the angled orientation of the antenna elements 32T, 32R on the proximal surface 32b, signals transmitted by the antenna element 32T and / or received from the antenna element 32R may be more narrowly focused along the longitudinal axis 25, e.g., to enhance the directivity of the probe 20. Additionally, providing the antenna elements 32T, 32R extending at an angle relative to the axis 25 may reduce the outer profile of the base 32 (and thus reduce the outer diameter or other cross-section of the distal end 24 of the probe 20) for a given size antenna element, e.g., as compared to an antenna element of the same size disposed on a flat proximal surface of the base (not shown), such as disclosed in the disclosures incorporated herein by reference, which may allow the outer profile of the probe 20 to be reduced without reducing the power and / or sensitivity of the probe 20.

[0048] The probe 20 and system 10 may be used during a medical procedure (e.g., in a breast biopsy or tumor resection procedure) to facilitate, for example, the use of one or more markers to facilitate the location of a lesion or other target tissue region. Figure 5A and Figure 5B, shows an exemplary embodiment of a passive marker or tag 40 that may be implanted in a patient's body, such as in a breast 90, for example. Fig. 9 . Typically, the marker 40 includes an electronic package 42 connected to a pair of wires or antennas 44. In an exemplary embodiment, each wire 44 can be an elongated member (e.g., a solid or hollow structure) having a diameter or other maximum cross-section between about half a millimeter and two millimeters (0.5mm-2mm) and a length between about one millimeter and ten millimeters (1.0mm-10mm). The wire 44 can be formed by elastic or superelastic materials and / or by shape memory materials (e.g., stainless steel, nitinol, etc.) so that the wire 44 is biased to a predetermined shape when deployed in the tissue, but can be elastically deformed, for example, to facilitate delivery, as described elsewhere in this article. Alternatively, the wire 44 can be substantially rigid so that the marker 40 maintains a substantially fixed shape, such as a linear or curved shape. As described elsewhere in this article, the wire 44 can act as an antenna and / or otherwise cooperate with the electronic components in the electronic package 42.

[0049] like Figure 5A and Figure 5B As shown in , the wires 44 can be biased to present a substantially linear configuration, such as so that the wires 44 extend substantially parallel to the longitudinal axis 48 of the marker 40. Optionally, one or both wires 44 can be offset from the longitudinal axis 48, which can enhance the loading of the marker 40 within a delivery device (not shown), as described elsewhere herein. Optionally, the wires 44 can carry one or more beads or other elements (not shown), such as similar to the embodiments described in the disclosure incorporated herein by reference.

[0050] As shown, each wire 44 may include a first end 44a coupled to a printed circuit board (PCB) or other circuit 50 within the package 42 and a second free end 44b terminating in an enlarged and / or rounded tip 45. Optionally, the first end 44a may include one or more bends, such as to facilitate coupling the first end 44a to the circuit 50 and / or to allow the wire 44 to extend tangentially from the opposite side of the package 42. Alternatively, the wire 44 may be biased to assume a curvilinear configuration or other configuration (e.g., a spiral shape, a serpentine shape, or other curved shape) about the longitudinal axis 48. For example, the wire 44 may be formed of an elastic or superelastic material that is shaped so that the wire 44 is biased to the spiral configuration shown, but may also be elastically straightened to a substantially linear configuration, such as to facilitate loading the marker 40 into a delivery device and / or otherwise introducing the marker 40 into a patient's body, such as described in the applications incorporated herein by reference.

[0051] Additional references Figure 6 , the marker 40 may include one or more circuits or other electronic components 50 that are enclosed or embedded in an electronic package 42 and configured to modulate an incident signal from the probe 20. In an exemplary embodiment, a semiconductor chip, a printed circuit board (PCB), and / or other circuit 50 may be carried in a package 42 that includes a voltage or power supply or other power or energy converter 52, a switch 54 that can be opened and closed when the energy converter 52 generates electrical energy, and an electrostatic discharge (ESD) protection device 58.

[0052] In an exemplary embodiment, the energy converter 52 includes a plurality of photosensitive diodes that are capable of converting incident light (e.g., infrared light) striking them into electrical energy (e.g., a predetermined minimum voltage). As shown, multiple pairs of diodes 52 can be connected in series, and the diodes can be spatially arranged orthogonally to each other within the package 42. For example, given that the photosensitive diodes are directional, at least two pairs of diodes 52 can be offset one hundred eighty degrees (180°) relative to each other or otherwise mounted within the package 42, such that at least one pair of diodes 52 can receive light from the light emitter of the probe 1020, regardless of the orientation of the post-implantation marker 40 relative to the probe 1020. The package 42 can be at least partially transparent, or the diodes 52 can be exposed so that the diodes 52 can receive light directed toward the package 42. Additionally or alternatively, the package 42 and / or the diodes 52 can include one or more coatings and / or filters, such as disclosed in the applications incorporated herein by reference.

[0053] exist Figure 6 In the embodiment shown in , switch 54 can be a field effect transistor (FET) (e.g., a junction field effect transistor (JFET)), wherein one end of diode 52 is coupled to the gate (G) and the other end is coupled to the source (S), and resistor 56 is coupled between the gate (G) and the source (S), for example to discharge diode 52 when there is no IR light. In an exemplary embodiment, switch 54 can include an enhancement mode pseudomorphic high electron mobility transistor (E-pHEMT), such as VMMK-1225 manufactured by Avago Technologies US Inc., and resistor 56 can be a three megohm (3MΩ) resistor. In an alternative embodiment, switch 54 can be a Schottky diode coupled to diode 52 (or other voltage source), for example, wherein the opposite end of the diode is coupled to wire 44.

[0054] As also shown, the source (S) of the switch 54 can be electrically coupled to one of the wires 44, and the drain (D) can be coupled to the other wire 44, for example, so that the wire 44 provides an antenna for the marker 40. For example, the components of the circuit 50 can be mounted within the package 52 so that the components are electrically isolated from each other, rather than as shown in FIG. Figure 6 Wire 44 may be bonded or otherwise attached to package 52 such that an end of wire 44 is electrically coupled to switch 54, as shown.

[0055] When exposed to light, each diode 52 is capable of generating sufficient voltage (e.g., about half a volt (0.5 V)) to open and close the switch 54 with little or no load (i.e., current consumption). Since the circuit 50 is intended to modulate only the signal from the probe 1020, little or no current is required, so the power required by the diode 52 (and therefore from the probe 1020) may be minimal, thereby reducing the power requirements of the marker 40 and the probe 1020.

[0056] Additional references Fig. 7A and Figure 7B , light intermittently shining on diode 52 can generate a voltage between gate (G) and source (S) to provide a control signal that can open and close switch 54. For example, Fig. 7A The switch 54 is shown in an open configuration when infrared light is not present, and Figure 7B The switch 54 is shown in a closed configuration when infrared light 70 strikes the diode 52, thereby connecting the two wires 44 together. Thus, the result is that the marker 40 provides a passive tag that includes a device equivalent to a high frequency switch in the middle of the marker 40. By being able to change the switch 54 from closed to open, the reflective characteristics of the antenna provided by the wire 44 can be significantly changed. For example, the switch 54 can change polarity or otherwise modulate the signal reflected from the marker 40 when the switch 54 is opened and closed.

[0057] Some challenges involved in detecting markers implanted in breast tissue (or elsewhere in the patient's body) include the relatively small radar cross section (RCS) of such markers and contamination of the received reflected signal due, for example, to (a) scattering caused by tissue inhomogeneities; (b) crosstalk between the probe's transmit and receive antennas; and (c) signal distortion due to near-field effects and other factors. To address these complicating factors and distinguish the reflected marker signal from the contaminant signal received by the probe, the switch 54 provides a periodic modulation of the reflective characteristics of the marker 40.

[0058] Specifically, the marker 40 is provided in two form factors (e.g. Fig. 7A and Figure 7B40) periodically changes its structure between the reflectors shown in FIG. 40. For example, as further described elsewhere herein, digital signal processing of the received signal using ultra-wideband (UWB) radar uses synchronous detection of the signal modulated with the marker switching frequency. This significantly increases the signal-to-noise ratio (SNR) of the marker signal because other contaminating signals remain unchanged during the modulation period. To provide a mechanism for a synchronous detector, the marker switching process is controlled in the probe 20 by illuminating the breast tissue with near infrared (IR) light pulses received by the marker 40.

[0059] The switching of the marker reflective form factor is controlled by a set of diodes 52 operating in photovoltaic mode. When the diodes 52 receive light from the probe 102 (by Figure 7B ), the diode 52 generates a voltage applied between the gate (G) and the source (S) of the switch 54, and the switch is closed and connects the drain (D) and the source (S) together, so that the wires 44 of the two antennas are connected together, as shown in FIG. Figure 7B When the light is turned off, the switch 54 is open and the drain (D) and source (S) are electrically disconnected, as shown in FIG. Fig. 7A as shown in .

[0060] In addition, the ESD device 58 can be connected in parallel across the switch 54, for example, between the drain (D) and the source (S), to provide protection against electrostatic discharge events. For example, using an E-pHEMT device as the switch 54 sets a limit on the absolute maximum voltage between the drain (D) and the source (S), and therefore on the antenna of the marker. In an exemplary embodiment of the VMMK-1225E-pHEMT, the maximum voltage across the switch 54 may not exceed about five volts (5V). Modern breast surgery typically involves the use of electric cutting tools, electro-moxibustion tools, and / or other tools (not shown) that can generate several kilovolts (kV) of electrical pulses. If such a tool is close to the marker 40, the tool may generate a very large voltage on the wire 44 of the antenna and destroy the switch 54.

[0061] To increase the durability of the marker 40 during operation of such a tool, the ESD protection device 58 cuts off the voltage on the switch 58 device when the voltage approaches a maximum value. Generally, the ESD protection device 58 in the marker 40 should have a low capacitance that does not shunt the antenna 44 for the frequency range of the small amplitude UWB signal from the probe 1020. In an exemplary embodiment, the ESD protection device 58 can be a transient voltage suppressor, such as a Zener diode, a low capacitance varistor, etc.

[0062] The system 10 (the system includes, for example, a probe 20 and one or more markers 40, such as Figure 1) can be used during a medical procedure (e.g., in a breast biopsy or tumor resection procedure) to, for example, facilitate the location of a lesion or other target tissue area and / or facilitate the dissection and / or removal of a sample from a breast 90 or other body structure, e.g., as Fig. 9 It should be noted that although system 10 is described as being particularly useful in localizing breast lesions, system 10 may also be used for localizing other objects in other areas of the body, such as described in the applications incorporated herein by reference.

[0063] Prior to the procedure, target tissue areas, such as tumors or other lesions, may be identified using conventional methods. For example, a lesion (not shown) within the breast 90 may be identified, for example, using mammography and / or other imaging, and a decision may be made to remove the lesion. The marker 40 may be delivered, for example, using a needle or other delivery device (e.g., Fig. 8A and Figure 8B The delivery device 60 shown in FIG. 1 is implanted within or near a target lesion within a breast 90.

[0064] exist Fig. 8A and Figure 8B In the embodiment shown in , the delivery device 60 may include a shaft 62 including a proximal end 62a and a distal end 62b, the distal end being sized for introduction through tissue into a target tissue region (not shown), and carrying (a plurality of) markers 40. The delivery device 60 may include a lumen 64 extending at least partially between the proximal end 62a and the distal end 62b of the shaft 62, and a pusher member 66 slidable within the shaft 62 for selectively delivering one or more markers 40, either continuously or otherwise independently of the lumen 64.

[0065] As shown, the distal end 62b of the shaft 62 can be beveled, pointed and / or otherwise sharpened so that the shaft 62 can be introduced directly through tissue. Alternatively, the delivery device 60 can be introduced through a cannula, sheath or other tubular member (not shown) previously placed through tissue, such as described in the applications incorporated herein by reference. Optionally, the distal end 62b can include a band or other features, such as formed of a radiopaque, echogenic or other material, which can help monitor the distal end 62b during introduction, such as using fluoroscopy, ultrasound, electromagnetic signals, etc.

[0066] As shown, the pusher member 66 includes a piston or other element (not shown) disposed within the lumen 64 adjacent to the marker(s) 40, and a plunger or other actuator 68 coupled to the piston to push the marker(s) 40 from the lumen 64. For example, Fig. 8AAs shown in , the distal end 62a of the shaft 62 (carrying the marker 40 therein) can be inserted into the breast 90 (or other tissue) and advanced or otherwise positioned to place the marker 40 at a target location (e.g., within a cancerous lesion (not shown)). Optionally, external imaging can be used to confirm the position of the marker 40 relative to the lesion. Once at the target location, the shaft 62 can be withdrawn relative to the pusher member 66, thereby deploying the marker 40, such as Figure 8B Optionally, the delivery device 60 may carry multiple markers (not shown), and the shaft 62 may be repositioned one or more times to deploy additional markers.

[0067] Alternatively, if desired, the pusher member 66 can be advanced to continuously deploy marker(s) 40 from the lumen 64, rather than retracting the shaft 62. In another alternative, a trigger device or other automated actuator (not shown) can be provided on the proximal end 62a of the shaft 62, which can fully retract the shaft 62 each time it is activated, such as to deliver a single marker 40 from the distal end 62b, such as described in the applications incorporated herein by reference.

[0068] Once the marker(s) 40 are implanted, as Fig. 9 , the probe 20 may be placed against the patient's skin, such as against a breast 90. Signals from the antenna(s) 32T of the probe 20 may be delivered along with the pulsed light from the light source to cause the switch 54 to open and close when the marker 40 receives the signal and reflects it back to the probe 20. If there is a lot of clutter, crosstalk, or other noise received by the probe 20, such as due to the probe antenna, tissue or other structures within the patient's body near the marker 40, etc., the reflected signals from the two states (switch 54 open and closed) may be subtracted from each other, substantially canceling the other noise and allowing the probe 20 to identify and / or locate the marker 40. Thus, the probe 20 may use the modulated reflected signal to increase the signal-to-noise ratio of the signal.

[0069] The display 38a can display information to the user to facilitate locating the marker 40 within the breast 90. For example, the display 38a can be simply a readout that provides distance, angle, orientation, and / or other data based on a predetermined criterion (e.g., based on the relative distance from the marker 40 to the probe 20). The distance information can be displayed as a numerical value representing the distance in units of length, such as in inches (in.) or centimeters (cm). Additionally or alternatively, a speaker 38b on the display unit 38 can produce an audible indication of the distance, such as spaced pulses whose speed increases as the probe 20 gets closer to the marker 40. In another alternative, the display 38a can present a graphical image (e.g., a two-dimensional image or a three-dimensional image) depicting the marker 40, the probe 20, the distance from the probe 20 to the marker 40, and / or a physiological picture of the body part (e.g., the breast) containing the marker.

[0070] For example, Fig. 9 As shown in , the distal end 24 of the probe 20 can be placed adjacent to or in contact with the patient's skin (e.g., generally above a lesion), and / or otherwise generally oriented toward the lesion and marker 40, and activated. A transmitting antenna (not shown) of the probe 20 can emit electromagnetic signals 34T, which pass through the tissue and reflect off the marker 40. The return signal 34R can be reflected back to a receiving antenna (not shown) in the probe 20, which can then determine the spatial relationship (e.g., distance and / or orientation angle) between the marker 40 and the distal end 24 of the probe 20 to facilitate determining an appropriate dissection direction for the surgeon.

[0071] In addition, substantially simultaneously, the probe 20 may emit light pulses 38a which may be received by the diode 52 of the marker 40 (not shown, see e.g. Fig. 7A and Figure 7B ). Diode 52 can alternately generate a voltage, thereby causing switch 54 to open and close. This causes marker 40 to change the phase of the signal reflected back to probe 20, which can process these signals, such as by subtraction, to identify and / or locate marker 40, and therefore identify and / or locate the target lesion.

[0072] The tissue can then be dissected, for example, by creating an incision in the patient's skin and dissecting the intervening tissue to a desired depth, corresponding, for example, to reaching a target margin around the lesion. The tissue sample can be resected or otherwise removed using a conventional tumor resection procedure, with, for example, the marker 40 remaining within the removed sample 1046.

[0073] It will be appreciated that elements or components shown in any embodiment herein are exemplary for that particular embodiment and may be used on or in conjunction with other embodiments disclosed herein.

[0074] Although the present disclosure is susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and described in detail herein. However, it should be understood that the present invention is not limited to the specific forms or methods disclosed, but on the contrary, the present invention will cover all modifications, equivalents and substitutes falling within the scope of the appended claims.

Claims

1. A probe for locating a marker in a patient's body, the probe comprising: a first member comprising a proximal end, a distal end configured to be placed adjacent a patient's body, and a longitudinal axis extending between the proximal end and the distal end; an antenna assembly adjacent the distal end, the antenna assembly comprising: a plurality of antenna elements; and A base comprising a non-conductive material, the exterior of the base comprising: a flat distal surface extending perpendicular to the longitudinal axis, and a plurality of proximal surfaces extending from a peak of the longitudinal axis at an acute angle relative to the longitudinal axis to the flat distal surface such that the base defines a pyramidal shape, wherein the antenna element is located on each proximal surface such that the proximal surface of the base provides support for the antenna element to be at an acute angle relative to the longitudinal axis; and A controller is coupled to the antenna elements for transmitting transmit signals into the patient's body and receiving reflected signals reflected from markers within the patient's body to identify or locate the markers.

2. The probe according to claim 1, wherein: The base includes four proximal surfaces offset from each other about the longitudinal axis, and wherein the antenna elements include a pair of transmitting antenna elements on opposite proximal surfaces and a pair of receiving antenna elements on opposite proximal surfaces offset from the transmitting antenna elements, such that the transmitting antenna and the receiving antenna define a butterfly antenna element configured as a Maltese cross.

3. The probe according to claim 1, wherein: Each of the proximal surfaces defines a plane that defines an acute angle relative to the longitudinal axis.

4. The probe according to any one of claims 1 to 3, wherein: The controller is configured to determine a distance from the distal end to the marker based at least in part on the transmitted signal and the received signal.

5. The probe of any one of claims 1-3, further comprising a display configured to present information representing the distance from the distal end to the marker.

6. The probe as described in any one of claims 1-3 further includes a signal generator, which is connected to one or more transmitting antennas of these antenna elements to generate an oscillating signal sent to the one or more transmitting antennas, and the one or more transmitting antennas convert the oscillating signal into a pulse signal for transmission into the patient's body.

7. The probe according to any one of claims 1 to 3, wherein: The base includes a ceramic material.

8. The probe according to any one of claims 1 to 3, wherein: The base is formed from a material having a dielectric constant similar to that of tissue.

9. The probe according to any one of claims 1 to 3, wherein: The base is formed of a material having a dielectric constant of at least twenty.

10. The probe according to any one of claims 1 to 3, wherein: The areas adjacent the proximal surfaces provide a dielectric or impedance mismatch with the material of the base to enhance the directionality of the transmitted signals from the probe distally into the patient's body.

11. The probe according to claim 10, wherein: This area includes air.

12. The probe according to claim 7, wherein: The antenna elements include material printed or deposited on the proximal surface of the ceramic material.

13. The probe according to any one of claims 1-3 and 11-12, wherein: The base includes grooves between adjacent side surfaces to isolate the antenna elements from each other.

14. The probe of any of claims 1-3 and 11-12, further comprising a shield surrounding the distal end to shield the antenna elements.

15. The probe according to claim 14, wherein: The shield includes an inner insulating layer and an outer Faraday shield surrounding the inner insulating layer.

16. The probe according to any one of claims 1-2, 11-12 and 15, wherein: Each of the proximal surfaces defines a plane that defines an acute angle relative to the longitudinal axis.

17. The probe according to any one of claims 1-2, 11-12 and 15, wherein: Each of these proximal surfaces has one of a convex shape and a concave shape.

18. A probe for locating a marker in a patient's body, the probe comprising: a first member comprising a proximal end, a distal end configured to be placed adjacent a patient's body, and a longitudinal axis extending between the proximal end and the distal end; an antenna assembly adjacent the distal end, the antenna assembly comprising: A base comprising a non-conductive material, the exterior of the base forming: a flat distal surface extending perpendicular to the longitudinal axis, and four proximal surfaces extending from a peak of the longitudinal axis at an angle relative to the longitudinal axis to the flat distal surface such that the base defines a pyramid shape; and on the proximal surfaces such that the proximal surface of the base provides support for the antenna elements at an acute angle to the antenna elements, and radial slots between adjacent side surfaces to isolate the antenna elements from each other; and A controller is connected to the antenna elements for causing one or more of the antenna elements to transmit signals into the patient's body and for receiving, via one or more of the antenna elements, reflected signals reflected from a marker implanted in the patient's body, the controller processing the reflected signals to identify or locate the marker.

19. The probe of claim 18, wherein: The antenna elements include a pair of transmit antenna elements on opposing proximal surfaces and a pair of receive antenna elements on opposing proximal surfaces offset from the transmit antenna elements such that the transmit antenna and the receive antenna define a bowtie antenna element configured as a Maltese cross.

20. A system for identifying and locating a marker within a patient's body, the system comprising: a delivery device for delivering the marker into the body of a patient; An antenna probe, the antenna probe comprising: a proximal end, a distal end configured for placement adjacent a patient's body, and a longitudinal axis extending between the proximal end and the distal end, and an antenna assembly adjacent the distal end, the antenna assembly comprising: a plurality of antenna elements; and A base, the base comprising a non-conductive material, the exterior of the base forming: a flat distal surface extending perpendicular to the longitudinal axis, and a plurality of proximal surfaces extending from a peak of the longitudinal axis at an angle relative to the longitudinal axis to the flat distal surface such that the base defines a pyramidal shape, wherein the antenna elements are positioned on each proximal surface such that the proximal surface of the base provides support to facilitate the multiple antenna elements at an acute angle; and A controller is coupled to the antenna elements for transmitting transmit signals into the patient's body and receiving reflected signals reflected from markers within the patient's body to identify or locate the markers.

21. The system of claim 20, further comprising an output device for presenting information related to the distance from the distal end of the probe to the marker.

22. The system of claim 21, wherein: The output device includes at least one of a display and a speaker.

23. The system of any one of claims 20-22, wherein: The antenna elements include a pair of transmit antenna elements on opposing proximal surfaces and a pair of receive antenna elements on opposing proximal surfaces offset from the transmit antenna elements such that the transmit antenna and the receive antenna define a bowtie antenna element configured as a Maltese cross.

24. A method for locating a marker in a body, the method comprising: placing a distal end of a probe against tissue, the probe comprising an antenna assembly adjacent the distal end, the antenna assembly comprising: a plurality of antenna elements and a base comprising a non-conductive material, the exterior of the base forming: a flat distal surface disposed adjacent the tissue and extending perpendicular to the longitudinal axis, and a plurality of proximal surfaces extending from a peak of the longitudinal axis to the flat distal surface at an angle relative to the longitudinal axis of the probe such that the base defines a pyramidal shape, wherein the antenna elements are positioned on each proximal surface such that the proximal surface of the base provides support for the plurality of antenna elements at an acute angle; transmitting a transmit signal into the body via one or more transmit antenna elements on one or more of the proximal surfaces; receiving, by one or more receive antenna elements on one or more of the proximal surfaces, a receive signal reflected from the marker; and The marker is identified or located based at least in part on the received signals.

25. The method of claim 24, wherein: Identifying the marker includes providing an output proportional to the distance from the distal end to the marker.

26. The method of claim 25, wherein: Providing an output includes displaying the distance from the distal end to the marker on a display.

27. The method of any one of claims 24 to 26, wherein: The base includes four proximal surfaces spaced apart from each other, and wherein the one or more transmitting antenna elements include a butterfly transmitting antenna, and the one or more receiving antenna elements include a butterfly receiving antenna offset from the transmitting antenna, so that the transmitting antenna and the receiving antenna together form a Maltese cross antenna.

28. The method of any one of claims 24 to 26, wherein: The base includes a ceramic material that provides impedance matching to the tissue.

29. The method of any one of claims 24 to 26, wherein: The base is formed of a material having a dielectric constant similar to that of tissue to enhance transmission of the transmit signals into the body and reception of the receive signals from the body.

30. The method of any one of claims 24 to 26, wherein: The base is formed of a material having a dielectric constant of at least twenty.

31. The method of any one of claims 24 to 26, wherein: The areas adjacent the proximal surfaces provide a dielectric or impedance mismatch with the material of the base to enhance the directionality of the transmitted signals from the probe distally into the patient's body.

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