Patent Description:
Before a biopsy or surgical procedure to remove a lesion within a breast, e.g., during a lumpectomy procedure, the location of the lesion must be identified. For example, mammography or ultrasound imaging may be used to identify and/or confirm the location of the lesion before the procedure. The resulting images may be used by a surgeon during the procedure to identify the location of the lesion and guide the surgeon, e.g., during dissection to access and/or remove the lesion. However, such images are generally two dimensional and therefore provide only limited guidance for localization of the lesion since the breast and any lesion to be removed are three-dimensional structures. Further, such images may provide only limited guidance in determining a proper margin around the lesion, i.e., defining a desired specimen volume to be removed.

To facilitate localization, immediately before a procedure, a wire may be inserted into the breast, e.g., via a needle, such that a tip of the wire is positioned at the location of the lesion. Once the wire is positioned, it may be secured in place, e.g., using a bandage or tape applied to the patient's skin where the wire emerges from the breast. With the wire placed and secured in position, the patient may proceed to surgery, e.g., to have a biopsy or lumpectomy performed.

One problem with using a wire for localization is that the wire may move between the time of placement and the surgical procedure. For example, if the wire is not secured sufficiently, the wire may move relative to the tract used to access the lesion and consequently the tip may misrepresent the location of the lesion. If this occurs, when the location is accessed and tissue removed, the lesion may not be fully removed and/or healthy tissue may be unnecessarily removed. In addition, during the procedure, the surgeon may merely estimate the location of the wire tip and lesion, e.g., based on mammograms or other images obtained during wire placement, and may proceed with dissection without any further guidance. Again, since such images are two dimensional, they may provide limited guidance to localize the lesion being treated or removed.

Alternatively, it has been suggested to place a radioactive seed to provide localization during a procedure. For example, a needle may be introduced through a breast into a lesion, and then a seed may be deployed from the needle. The needle may be withdrawn, and the position of the seed may be confirmed using mammography. During a subsequent surgical procedure, a hand-held gamma probe may be placed over the breast to identify a location overlying the seed. An incision may be made and the probe may be used to guide excision of the seed and lesion.

Because the seed is delivered through a needle that is immediately removed, there is risk that the seed may migrate within the patient's body between the time of placement and the surgical procedure. Thus, similar to using a localization wire, the seed may not accurately identify the location of the lesion, particularly, since there is no external way to stabilize the seed once placed. Further, such gamma probes may not provide desired precision in identifying the location of the seed, e.g., in three dimensions, and therefore may only provide limited guidance in localizing a lesion.

Accordingly, apparatus and methods for localization of lesions or other tissue structures in advance of and/or during surgical, diagnostic, or other medical procedures would be useful.

<CIT> dislcoses an apparatus for localizing lesions within a patient's body. A marker is implanted into a target tissue region and a microwave antenna probe is placed against the patient's skin to transmit a signal to the marker and to receive the reflected signal from the marker in order to determine the location of the marker.

The present invention is directed to implantable markers and tags, and to systems for localizing such markers within a patient's body, e.g., during surgical procedures or other procedures, such as during lumpectomy procedures.

In accordance with one embodiment, a marker is provided sized for introduction into a target tissue region within a patient's body that includes an energy converter for transforming energy pulses striking the marker into electrical energy; a switch coupled to the energy converter such that the energy pulses cause the switch to open and close; a pair of elongate wires coupled to the switch to provide an antenna, the switch configured to open and close to modulate signals reflected by the antenna back to a source of the signals; and an electro static discharge (ESD) protection device coupled to the switch to provide protection against an electrostatic discharge event.

In accordance with another embodiment, a marker is provided for introduction into a target tissue region within a patient's body that includes a field effect transistor (FET); one or more photosensitive diodes coupled in series across a source and a gate of the FET to convert light pulses received from a light source to generate a voltage to open and close the FET; a pair of elongate wires coupled to a drain and the source of the FET to provide an antenna, the FET configured to open and close to modulate signals reflected by the antenna back to a source of the signals; and an electro static discharge (ESD) protection device coupled between the drain and the source of the FET to set a maximal voltage between the drain and the source.

In accordance with still another embodiment, a system is provided for localizing a marker within a body that includes a marker including an energy converter; a probe comprising a transmit antenna configured to transmit a transmit signal into the body towards the marker, a receive antenna configured to receive a receive signal that is reflected from the marker, and an energy source for delivering energy pulses into the body to open and close the switch and modulate signals reflected by the marker back to the receive antenna; a processor coupled to the receive antenna for locating or otherwise detecting the marker within the body based at least in part on the modulated signals reflected by the marker; and a display to present information representing the distance from the tip of the probe to the marker and/or other information related to the location of the marker within the patient's body. In an exemplary embodiment, the energy source may include a light source, and the energy converter may include one or more photosensitive diodes configured to convert light from the light source to generate a voltage.

In one embodiment, the voltage may open and close a switch in the marker to modulate an antenna of the marker to modulate the signals reflected by the marker. In addition, the marker may include an electro static discharge (ESD) protection device coupled to the switch to provide protection against an electrostatic discharge event. In another embodiment, the voltage may intermittently induce a current in a conductor loop of the marker, which may modulate the signals reflected by the marker.

In accordance with yet another embodiment, a system is provided for localization of a target tissue region within a patient's body that includes a probe including one or more antennas for transmitting electromagnetic signals into a patient's body and receiving reflected signals from the patient's body, and an energy source for delivering energy pulses into a patient's body. The system also includes a marker sized for implantation within a patient's body, the marker including an energy converter configured to transform the energy pulses from the energy source into electrical energy, and a switch coupled to the energy converter such that the energy pulses cause the switch to open and close to modulate the electromagnetic signals from the probe reflected by the marker, and an electro static discharge (ESD) protection device coupled to the switch to provide protection against an electrostatic discharge event.

In accordance with another embodiment, a method is provided for localization of a target tissue region within a patient's body that includes implanting a marker within a patient's body, the marker including a switch, an energy converter, and an electro static discharge (ESD) protection device; placing a probe adjacent the patient's body oriented towards the marker; and activating the probe to a) transmit electromagnetic signals into the patient's body, b) receive reflected signals from the patient's body, and c) deliver energy pulses into the patient's body such that the energy converter transforms the energy pulses into electrical energy to open and close the switch to modulate the electromagnetic signals from the probe reflected by the marker, and wherein the ESD protection device provides protection against an electrostatic discharge event. In an exemplary embodiment, delivering energy pulses into the patient's body may include delivering infrared light into the patient's body, and the energy converter may include one or more photosensitive diodes that transform the infrared light into electrical energy to open and close the switch to modulate the electromagnetic signals from the probe reflected by the marker. In addition, the probe may provide information related to the location of the marker within the patient's body and/or relative to the probe.

In one embodiment, the method may include using an electrical tool adjacent the marker, and the ESD protection device may be activated when electrical energy from the tool exceeds a maximal voltage for the switch.

In accordance with still another embodiment, a system is provided for localization of a target tissue region within a patient's body that includes a probe including one or more antennas for transmitting electromagnetic signals into a patient's body and receiving reflected signals from the patient's body, and a light source for delivering light pulses into a patient's body. The system also includes a marker sized for implantation within a patient's body, the marker including one or more photosensitive diodes coupled to a conductor loop configured to transform the light pulses from the light source into electrical energy to induce a current in the conductor loop and modulate the electromagnetic signals from the probe reflected by the marker.

In accordance with yet another embodiment, a method is provided for localization of a target tissue region within a patient's body that includes implanting a marker within a patient's body, the marker including one or more photosensitive diodes coupled to a conductor loop; placing a probe adjacent the patient's body oriented towards the marker; and activating the probe to a) transmit electromagnetic signals into the patient's body, b) receive reflected signals from the patient's body, c) deliver light pulses into the patient's body such that the one or more photosensitive diodes transform the light pulses into electrical energy to induce a current in the conductor loop and modulate the electromagnetic signals from the probe reflected by the marker, and d) provide an output related to the location of the marker within the patient's body.

Other aspects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.

These and other features, aspects, and advantages of the present disclosure will become better understood with regard to the following description, appended claims, and accompanying drawings, whereby <FIG> show the marker according to appended claim <NUM>, and where:.

In the following description, numerous details are set forth in order to provide a more thorough description of the system. It will be apparent, however, to one skilled in the art, that the disclosed system may be practised without these specific details. In the other instances, well known features have not been described in detail so as not to unnecessarily obscure the system.

Turning to the drawings, <FIG> show an exemplary embodiment of a passive marker or tag <NUM> that may be implanted within a patient's body, such as within a breast <NUM>, e.g., as shown in <FIG>. Generally, the marker <NUM> includes an electronics package <NUM> coupled to a pair of wires or antennas <NUM>. The marker <NUM> may be included in a system <NUM> for performing a procedure, such as a lumpectomy procedure, e.g., including a delivery device <NUM> for delivering one or more of the markers into tissue, a probe <NUM> for locating marker(s) implanted within tissue, and/or other components, e.g., as shown in <FIG> and described further below.

In an exemplary embodiment, each wire <NUM> may be an elongate member, e.g., a solid or hollow structure having a diameter or other maximum cross-section between about half and two millimeters (<NUM>-<NUM>) and a length between about one and ten millimeters (<NUM>-<NUM>). The wires <NUM> may be formed from elastic or superelastic material and/or from shape memory material, e.g., stainless steel, Nitinol, and the like, such that the wires <NUM> are biased to a predetermined shape when deployed within tissue, but may be elastically deformed, e.g., to facilitate delivery, as explained elsewhere herein. Alternatively, the wires <NUM> may be substantially rigid such that the marker <NUM> remains in a substantially fixed, e.g., linear or curved, shape. As described elsewhere herein, the wires <NUM> may act as antennas and/or otherwise cooperate with electrical components within the electronics package <NUM>.

Optionally, the wires <NUM> may carry one or more beads or other elements (not shown), e.g., similar to embodiments described in International Publication No. <CIT>. For example, the wires <NUM> may provide core wires that carry a plurality of beads or segments (not shown) including multiple surfaces, angles, and/or edges to enhance detection of the marker <NUM>. In an exemplary embodiment, the beads may include a plurality of individual annular bodies, e.g., each defining a portion of a generally cylindrical or spherical shape. The beads may be formed from desired materials, e.g., metals, such as stainless steel, Nitinol, titanium, and the like, plastic materials, or composite materials. During assembly, a plurality of beads may be placed over and secured to the wires <NUM>, e.g., before or after attaching the wires <NUM> to the electronics package <NUM>, e.g., as described in International Publication No. <CIT>.

As shown in <FIG>, the wires <NUM> may be biased to assume a substantially linear configuration, e.g., such that the wires <NUM> extend substantially parallel to a longitudinal axis <NUM> of the marker <NUM>. Optionally, one or both wires <NUM> may be offset from the longitudinal axis <NUM>, which may enhance loading the marker <NUM> within a delivery device (not shown), as described elsewhere herein.

As shown, each wire <NUM> includes a first end 44a coupled to a printed circuit board (PCB) or other circuit <NUM> within the package <NUM> and a second free end 44b terminating in an enlarged and/or rounded tip <NUM>. The first ends 44a include one or more bends to facilitate coupling the first ends 44a to the circuit <NUM> such that the wires <NUM> extend tangentially from opposite sides of the package <NUM>, as best seen in <FIG>.

Alternatively, the wires <NUM> may be biased to assume a curvilinear or other configuration, e.g., a helical, serpentine or other curved shape, around the longitudinal axis <NUM>. For example, the wires <NUM> may be formed from elastic or superelastic material that is shape set such that the wires <NUM> are biased to the helical configuration shown, yet may be resiliently straightened to a substantially linear configuration, e.g., to facilitate loading the marker <NUM> into a delivery device and/or otherwise introducing the marker <NUM> into a patient's body, e.g., as described in International Publication No. <CIT>.

With additional reference to <FIG>, the marker <NUM> includes one or more circuits or other electrical components <NUM> encased or embedded in the electronics package <NUM> and configured to modulate incident signals from a probe (not shown, such as the probe <NUM> shown in <FIG> and described elsewhere herein) used to locate the marker <NUM>, also as described elsewhere herein. In an exemplary embodiment, best seen in <FIG>, a semiconductor chip, print circuit board (PCB), and/or other circuit <NUM> may be carried in the package <NUM> that includes a voltage or power source or other power or energy converter <NUM>, a switch <NUM> that may be opened and closed when the energy converter <NUM> generate electrical energy, and an Electro Static Discharge (ESD) protection device <NUM>.

In an exemplary embodiment, the energy converter <NUM> includes a plurality of photosensitive diodes capable of transforming incident light (e.g., infrared light) striking them into electrical energy (e.g., a predetermined minimum voltage). As shown, multiple pairs of diodes <NUM> may be connected in series, which may be arranged orthogonally to one another spatially within the package <NUM>. For example, given that photosensitive diodes are directional, at least two pairs of diodes <NUM> may be mounted within the package <NUM> offset one hundred eighty degrees (<NUM>°) or otherwise relative to one another, e.g., as best seen in <FIG>, such that at least one pair of diodes <NUM> may receive light from a light transmitter of the probe <NUM> regardless of the orientation of the marker <NUM> relative to the probe <NUM> after implantation. The package <NUM> may be at least partially transparent or the diodes <NUM> may be exposed such that light directed towards the package <NUM> may be received by the diodes <NUM>.

In alternative embodiments, the energy converter <NUM> may include other components capable of transforming external energy into a desired voltage. For example, if the probe <NUM> includes another power source, e.g., a source of EMF, RF, or vibrational energy, the energy converter <NUM> may include a pick-up coil, antenna, or other device capable of transforming the incident energy into the desired voltage, e.g., including a capacitor and/or other components arranged to deliver the desired voltage to the switch <NUM>. One advantage of infrared energy is that it may pass sufficiently through tissue such that a probe <NUM> placed against a patient's skin may deliver sufficient energy to activate a relatively small marker <NUM> implanted several inches away within the patient's body, e.g., breast <NUM>, as shown in <FIG>.

In the embodiment shown in <FIG>, the switch <NUM> may be a field effect transistor (FET), e.g., a junction field effect transistor (JFET), with one end of the diodes <NUM> coupled to the gate (G) and the other coupled to the source (S), with a resistor <NUM> coupled between the gate (G) and the source (S), e.g., to discharge the diodes <NUM> when there is no IR light. In an exemplary embodiment, the switch <NUM> may include an enhancement mode pseudomorphic high electron mobility transistor (E-pHEMT), such as a VMMK-<NUM> manufactured by Avago Technologies US Inc. , and the resistor <NUM> may be a three megaOhm (3MΩ) resistor. In an alternative embodiment, the switch <NUM> may be a Schottky diode coupled to the diodes <NUM> (or other voltage source), e.g., with opposite ends of the diode coupled to the wires <NUM>.

Also as shown, the source (S) of the switch <NUM> may be electrically coupled to one of the wires <NUM> and the drain (D) may be coupled to the other wire <NUM>, e.g., such that the wires <NUM> provide an antenna for the marker <NUM>. For example, the components of the circuit <NUM> may be mounted within the package <NUM> such that the components are electrically isolated from one another other than as coupled in the schematic of <FIG>. The wires <NUM> may be bonded or otherwise attached to the package <NUM> such that ends of the wires <NUM> are electrically coupled to the switch <NUM> as shown.

Each diode <NUM> may be capable of generating sufficient voltage (e.g., about a half Volt (<NUM> V)) when exposed to light to open and close the switch <NUM> when there is little or no load (i.e., current draw). Since the circuit <NUM> is intended to be merely modulate signals from the probe <NUM>, little or no current is needed, and so the power required from the diodes <NUM> (and consequently from the probe <NUM>) may be minimal, thereby reducing power demands of the marker <NUM> and probe <NUM>.

With additional reference to <FIG>, light intermittently striking the diodes <NUM> may generate a voltage across the gate (G) and source (S) to provide a control signal that may open and close the switch <NUM>. For example, <FIG> shows the switch <NUM> in the open configuration when infrared light is absent, while <FIG> shows the switch <NUM> in the closed configuration when infrared light <NUM> strikes the diodes <NUM>, thereby connecting both wires <NUM> together. Thus, the result is that the marker <NUM> provides a passive tag that includes what equates to a high-frequency switch in the middle of the marker <NUM>. By being able to change the switch <NUM> from closed to open, the reflection properties of the antenna provided by the wires <NUM> may be changed significantly. For example, the switch <NUM> may change the polarity or otherwise modulate signals reflected from the marker <NUM> as the switch <NUM> is opened and closed.

Some of the challenges involved in detecting markers implanted within breast tissue (or elsewhere in a patient's body) include the relatively small radar cross-section (RCS) of such markers and contamination of the received reflected signal, e.g., due to (a) scattering caused by tissue inhomogeneity; (b) cross-talk between transmit and receive antennas of the probe; and (c) signal distortions due to near field effects and other factors. To deal with these complicating factors and distinguish the reflected marker signal from contaminating signals received by the probe, the switch <NUM> provides periodic modulation of reflective properties of the marker <NUM>.

Specifically, the marker <NUM> is made to periodically change its structure between two form factors, e.g., the reflectors shown in <FIG>. For example, as described further elsewhere herein, digital signal processing of the received signals using ultra-wideband (UWB) radar uses synchronous detection of the signal modulated with marker switching frequency. This significantly increases the signal-to-noise (SNR) on the marker signal because other contaminating signals remain unchanged within the modulation period. To provide a mechanism for a synchronous detector, the marker switching process is controlled in the probe <NUM> by illuminating breast tissue with near infrared (IR) light pulses that are received by the marker <NUM>.

Switching of the marker reflective form-factor is controlled with the set of diodes <NUM> operating in photovoltaic mode. When the diodes <NUM> receive light from the probe <NUM> (represented by arrows <NUM> in <FIG>), the diodes <NUM> generate voltage that is applied between the gate (G) and source (S) of the switch <NUM>,which closes and connects together the drain (D) and source (S) making both antenna wires <NUM> connected together, as shown in <FIG>. When the light is off, the switch <NUM> is open and the drain (D) and source (S) are electrically disconnected, as shown in <FIG>.

In addition, the ESD device <NUM> may be coupled in parallel across the switch <NUM>, e.g., between the drain (D) and source (S), to provide protection against an electrostatic discharge event. For example, use of an E-pHEMT device as switch <NUM> sets restrictions on the absolute maximal voltage between the drain (D) and source (S ) and, therefore, across the marker's antennas. In the exemplary embodiment of a VMMK-<NUM> E-pHEMT, the maximal voltage across the switch <NUM> may be no more than about five Volts (<NUM> V). Modern breast surgery often involves the use of electro-cutting tools, electocautery tools, and/or other tools (not shown), which can generate electrical pulses of a few kV. If such a tool gets close to the marker <NUM>, the tool can cause a very large voltage across antenna wires <NUM> and destroy the switch <NUM>.

To increase survivability of the marker <NUM> during operation of such tools, the ESD protection device <NUM> truncates voltage on the switch <NUM> device when the voltage approaches the maximal value. Generally, the ESD protection device <NUM> in the marker <NUM> should have low capacitance that does not shunt the antennas <NUM> for the frequency range of the small amplitude UWB signal coming from the signals from the probe <NUM>. In exemplary embodiments, the ESD protection device <NUM> may be a transient voltage suppressor, such as a Zener diode, a low-capacitance varistor, and the like.

Turning to <FIG>, an alternative embodiment of a passive marker <NUM>' is shown that includes a plurality of photosensitive diodes <NUM>' connected in series and the resulting output is coupled to a conductor loop <NUM>. ' The resulting current loop is modulated by a light trigger, e.g., using the probe <NUM> similar to the marker <NUM>, for synchronous detection. When the light triggers the photodiodes <NUM>,' current is induced in the conductor path of the conductor loop <NUM>,' thereby modulating the reflective characteristics of the marker <NUM>,' e.g., changing the scattering characteristics of the marker <NUM>. ' The probe <NUM> may subtract the difference between the two states of the marker <NUM>' and use the difference for synchronous detection.

Optionally, as shown in <FIG>, a needle or delivery device <NUM> may be provided for introducing one or more markers <NUM> or <NUM>' (one marker <NUM> shown) into a patient's body, e.g., similar to any of the embodiments described in International Publication No. <CIT>. For example, the delivery device <NUM> may include a shaft <NUM> including a proximal end 262a and a distal end 262b sized for introduction through tissue into a target tissue region (not shown) and carrying the marker(s) <NUM>. The delivery device <NUM> may include a lumen <NUM> extending at least partially between the proximal and distal ends 262a, 262b of the shaft <NUM>, and a pusher member <NUM> slidable within the shaft <NUM> for selectively delivering one or more markers <NUM> successively or otherwise independently from the lumen <NUM>.

As shown, the distal end 262b of the shaft <NUM> may be beveled, pointed, and/or otherwise sharpened such that the shaft <NUM> may be introduced directly through tissue. Alternatively, the delivery device <NUM> may be introduced through a cannula, sheath, or other tubular member (not shown) previously placed through tissue, e.g., as described in International Publication No. <CIT>. Optionally, the distal end 262b may include a band or other feature, e.g., formed from radiopaque, echogenic, or other material, which may facilitate monitoring the distal end 262b during introduction, e.g., using fluoroscopy, ultrasound, electromagnetic signals, and the like.

As shown, the pusher member <NUM> includes a piston or other element (not shown) disposed within the lumen <NUM> adjacent the marker(s) <NUM> and a plunger or other actuator <NUM> coupled to the piston to push the marker(s) <NUM> from the lumen <NUM>. For example, as shown in <FIG>, the distal end 262a of the shaft <NUM> (carrying the marker <NUM> therein) may be inserted into the breast <NUM> (or other tissue) and advanced or otherwise positioned to place the marker <NUM> at a target location, e.g., within a cancerous lesion (not shown). Optionally, external imaging may be used to confirm the location of the marker <NUM> relative to the lesion. Once at the target location, the shaft <NUM> may be withdrawn relative to the pusher member <NUM>, thereby deploying the marker <NUM>, as shown in <FIG>. Optionally, the delivery device <NUM> may carry multiple markers (not shown), and the shaft <NUM> may be repositioned one or more times to deploy additional markers.

Alternatively, if desired, the pusher member <NUM> may be advanced to deploy the marker(s) <NUM> successively from the lumen <NUM>, rather than retracting the shaft <NUM>. In another alternative, a trigger device or other automated actuator (not shown) may be provided on the proximal end 262a of the shaft <NUM>, which may retract the shaft <NUM> sufficiently with each activation, e.g., to delivery an individual marker <NUM> from the distal end 262b.

Optionally, one or both of the wires <NUM> may be offset from the longitudinal axis <NUM> to facilitate delivery of the marker(s) <NUM>. For example, one wire <NUM> may extend substantially parallel to the longitudinal axis <NUM> while the other wire <NUM> may define a predetermined acute angle relative to the longitudinal axis <NUM> such that the tips <NUM> of the wires <NUM> slidably engages an inner surface of the delivery device <NUM>, e.g., with sufficient friction to prevent the marker <NUM> from freely falling out of the lumen <NUM> unless the shaft <NUM> is retracted relative to the pusher member <NUM> with sufficient force to overcome the friction.

Turning to <FIG>, an exemplary embodiment of a system <NUM> is shown for localization of a target tissue region within a patient's body, such as a tumor, lesion, or other tissue structure within a breast <NUM> or other location within a body. As shown in <FIG>, the system <NUM> generally includes a delivery device <NUM> carrying one or more targets, tags, or markers <NUM> (one shown), a probe <NUM> for detecting and/or locating the marker <NUM>, e.g., using ultra-wideband radar, e.g., and a controller and/or display unit <NUM> coupled to the probe <NUM>, e.g., using one or more cables <NUM>, similar to embodiments described in International Publications Nos. <CIT> and <CIT>.

For example, the probe <NUM> may be a portable device having electromagnetic signal emitting and receiving capabilities, e.g., a micro-power impulse radar (MIR) probe, similar to embodiments described in International Publications Nos. <CIT> and <CIT>. As shown in <FIG>, the probe <NUM> may be a handheld device including a first or distal end <NUM> intended to be placed against or adjacent tissue, e.g., a patient's skin or underlying tissue, and a second or proximal end <NUM>, e.g., which may be held by a user. Generally, the probe <NUM> includes one or more antennas, e.g., a transmit antenna and a receive antenna (not shown) mounted on a ceramic disk <NUM> (shown in <FIG>). In addition, the probe <NUM> includes a light transmitter, e.g., a plurality of light fibers <NUM> (shown in <FIG>), configured to transmit light pulses (represented by dashed lines 1038a in <FIG>) into tissue contacted by the distal end <NUM>, e.g., into breast tissue <NUM>, as shown in <FIG>. The light fibers <NUM> may be coupled to a light source (not shown), e.g., by coupling <NUM>, such that light from the light source passes through the light fibers <NUM> distally from the distal end <NUM> of the probe <NUM>.

In an exemplary embodiment, the light source is an infrared light source, e.g., capable of delivering near infrared light between, for example, eight hundred and nine hundred fifty nanometers (<NUM>-<NUM>) wavelength. Optionally, the light fibers may include one or lenses, filters, and the like (not shown), if desired, for example, to focus the light transmitted by the probe <NUM> in a desired manner, e.g., in a relatively narrow beam extending substantially parallel to the central axis of the probe <NUM>, in a wider beam, and the like.

Alternatively, the probe <NUM> may include other energy sources instead of the light transmitter <NUM>. For example, a source of electromagnetic energy, radiofrequency (RF) energy, vibrational energy, and the like (not shown) may be provided on the distal end <NUM> of the probe <NUM> for delivering energy pulses to activate the marker <NUM>, as described elsewhere herein. The energy source(s) may be pulsed in a predetermined manner, e.g., to cause the circuits of the marker <NUM> to be alternately activated and deactivated.

The probe <NUM> may include a processor within the display unit <NUM> including one or more controllers, circuits, signal generators, gates, and the like (not shown) needed to generate signals for transmission by the transmit antenna and/or to process signals received from the receive antenna. The components of the processor may include discrete components, solid state devices, programmable devices, software components, and the like, as desired. For example, the probe <NUM> may include an impulse generator, e.g., a pulse generator and/or pseudo noise generator (not shown), coupled to the transmit antenna to generate transmit signals, and an impulse receiver for receiving signals detected by the receive antenna. The processor may include a micro-controller and a range gate control that alternately activate the impulse generator and impulse receiver to transmit electromagnetic pulses, waves, or other signals via the transmit antenna, and then receive any reflected electromagnetic signals via the receive antenna, e.g., similar to other embodiments herein. Exemplary signals that may be used include microwave, radio waves, such as micro-impulse radar signals, e.g., in the ultralow bandwidth region.

The probe <NUM> may be coupled to a display <NUM> of the display unit <NUM>, e.g., by cables <NUM>, for displaying information to a user of the probe <NUM>, e.g., spatial or image data obtained via the antennas. Optionally, the probe <NUM> may include other features or components, such as one or more user interfaces, memory, transmitters, receivers, connectors, cables, power sources, and the like (not shown). For example, the probe <NUM> may include one or more batteries or other internal power sources for operating the components of the probe <NUM>. Alternatively, the probe <NUM> may include a cable, such as one of the cables <NUM>, that may be coupled to an external power source, e.g., standard AC power, for operating the components of the probe <NUM>.

As shown in <FIG>, the internal components of the probe <NUM> may be provided in a housing or casing such that the probe <NUM> is self-contained. For example, the casing may be relatively small and portable, e.g., such that the entire probe <NUM> may be held in a user's hand. Optionally, a portion of the probe <NUM> may be disposable, e.g., a portion adjacent the distal end <NUM>, or a disposable cover, sleeve, and the like (not shown) may be provided if desired, such that at least a proximal portion of the probe <NUM> may be reusable, e.g., similar to other embodiments herein. Alternatively, the entire probe <NUM> may be a disposable, single-use device while the display unit <NUM> may be used during multiple procedures by connecting a new probe <NUM> to the display unit <NUM>, which may remain out of the surgical field yet remain accessible and/or visible, as desired. Additional information on construction and/or operation of the probe <NUM> may be found in International Publications Nos. <CIT> and <CIT>.

<FIG> is a block diagram <NUM> showing exemplary components of the probe <NUM> (although, alternatively, some of the components may be located within the display unit <NUM> of <FIG>). The probe <NUM> may include a signal generator <NUM>, an amplifier <NUM>, an analog-to-digital (A/D) converter <NUM>, and a digital signal processor (DSP) <NUM>. The signal generator <NUM>, e.g., a reference oscillator, produces an oscillating signal, such as a square wave signal, a triangular wave signal, or a sinusoidal signal.

For example, a square wave signal <NUM> may be sent from the signal generator <NUM> to the transmit antenna of the antenna portion <NUM> of the probe <NUM>. When the square wave signal <NUM> passes through the transmit antenna, the transmit antenna acts as a band pass filter ("BPF") and converts the square wave signal <NUM> to a series of pulses <NUM>. As such, the transmit signal 1034T (shown in <FIG>) transmitted by the probe <NUM> includes a series of pulses <NUM>. The transmit signals 1034T may be transmitted into the tissue and reflected from the marker <NUM> (as shown in <FIG>), as represented by the receive signals 1034R. Once the transmit signal 1034T is reflected from the marker <NUM>, the reflected signal (i.e., the receive signals 1034R) includes a series of attenuated pulses <NUM> (shown in <FIG>).

The receive antenna of the antenna portion <NUM> of the probe <NUM> may receive the receive signals 1034R (shown in <FIG>). As shown in <FIG>, the receive signals 1034R, which may include a series of attenuated pulses <NUM>, may be inputted into an amplifier <NUM> in order to amplify the gain of the pulses <NUM>. The output of the amplifier <NUM> may be inputted into an A/D converter <NUM> in order to convert the amplified analog signal into a digital signal. The digital signal output from the A/D converter <NUM> may be inputted into a DSP <NUM> for processing. The DSP <NUM> may perform a number of processing functions including, but not limited to, calculating a difference in time from the time the transmit signal <NUM> was sent to the time the receive signal <NUM> was received, determining the distance from the tip of the microwave antenna probe <NUM> to the marker <NUM>, determining the location of the marker <NUM> in relation to the tip of the probe <NUM>, measuring the amplitude of the receive signals 1034R, and/or determining the direction the marker <NUM> is located in relation to the tip of the probe <NUM>. The output of the DSP <NUM> may be presented on the display <NUM> of the display unit <NUM>.

Turning to <FIG>, an exemplary embodiment of an antenna probe <NUM> is shown that may be used in any of the systems and methods described elsewhere herein. Generally, the probe <NUM> includes a housing <NUM>, an antenna subassembly <NUM>, and shielding <NUM>. Optionally, the probe <NUM> may include an outer sleeve or cover (not shown) surrounding one or more components of the probe <NUM>, e.g., surrounding openings in the housing <NUM>, for reducing contamination, exposure, and/or otherwise protecting the internal components of the probe <NUM>.

With additional reference to <FIG>, the antenna subassembly <NUM> includes a transmit antenna 960t and a receive antenna 960r, each having a bowtie configuration, combined to form a Maltese cross antenna. As shown in <FIG>, each antenna <NUM> includes a pair of antenna elements <NUM> offset ninety degrees (<NUM>°) from one another on a disk or other base of dielectric material <NUM>. Each of the antenna elements <NUM> may be formed separately and then attached to the disk <NUM> or may be deposited directly onto the disk <NUM>. In an exemplary embodiment, the antenna elements <NUM> may be formed from silver film or other material deposited onto the top surface of ceramic disk <NUM>.

Circuitry <NUM> may be coupled to the antennas <NUM>, e.g., including a PCB <NUM> on which are provided one or more transformers <NUM> and connectors <NUM> coupled to the respective antenna elements <NUM> by appropriate leads. Coaxial cables <NUM> may be coupled to the connectors <NUM> to allow the antennas <NUM> to be coupled to other components of the system, similar to other embodiments described elsewhere herein.

As best seen in <FIG>, the disk <NUM> includes a plurality of radial slots <NUM> between the antenna elements <NUM>. Thus, the antenna elements <NUM> may be substantially isolated from one another by air within the slots <NUM>, which may increase sensitivity, reduce crosstalk and/or other noise, and the like. Alternatively, the slots <NUM> may be filled with other insulating material, e.g., foam and the like (not shown), which may have a desired relatively low dielectric constant to substantially isolate the antenna elements <NUM> from one another.

As best seen in <FIG>, the disk <NUM> may be mounted within the shielding <NUM>, which may in turn, be coupled to the tip <NUM> of the housing <NUM>, e.g., by one or more of bonding with adhesive, sonic welding, fusing, cooperating connectors (not shown), and the like. As shown, the shielding <NUM> includes an inner insulation layer, e.g., formed from a collar of nylon or other polymeric material, surrounded by a relatively thin outer shield <NUM>, e.g., formed from copper or other material, to provide a Faraday shield. In an exemplary embodiment, a layer of copper tape may be wrapped around the inner shield <NUM> with the ends secured together. Alternatively, the outer shield <NUM> may be a sleeve of shielding material into which the inner shield <NUM> is inserted and attached, e.g., by bonding with adhesive, interference fit, and the like.

As shown in <FIG>, the shielding <NUM> may have a length substantially greater than the thickness "t" of the disk <NUM>. For example, the inner shield <NUM> may include an annular recess <NUM> into which the disk <NUM> may be inserted and attached, e.g., by interference fit, bonding with adhesive, and the like. As shown, the bottom surface of the disk <NUM> may be substantially flush with the distal end of the shielding <NUM> such that the disk <NUM> 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 over the bottom surface of the disk <NUM> and/or the shielding <NUM>, e.g., to prevent fluids or other material entering the tip, reduce contamination, and/or otherwise protect the tip of the probe <NUM>.

With continued reference to <FIG>, the top surface of the disk <NUM> (with the antenna elements <NUM>, not shown, thereon) may be exposed to a region of air within the shielding <NUM>. Because of the low dielectric constant of air, the transmission from the transmit antenna 960t is focused distally, i.e., towards the tissue contacted by the disk <NUM>. With the material of the disk <NUM> chosen to substantially match the dielectric constant of tissue, the depth of transmission into the tissue may be enhanced. The air behind the disk <NUM> may minimize lost energy that would otherwise be emitted by the transmit antenna 960t away from the tissue. Similarly, the disk <NUM> may focus the sensitivity of the receive antenna 960r directed towards the tissue. The air behind the disk <NUM> within the shielding <NUM> (as well as the slots <NUM> between the antenna elements <NUM>) may minimize crosstalk, noise and/or may otherwise enhance operation of the probe <NUM>. Additional information regarding the probe <NUM> and/or alternative embodiments may be found in International Publications Nos. <CIT> and <CIT>.

The system <NUM> of <FIG> may be used during a medical procedure, for example, in a breast biopsy or lumpectomy procedure, e.g., to facilitate localization of a lesion or other target tissue region and/or to facilitate dissection and/or removal of a specimen from a breast <NUM> or other body structure. It should be noted that, although the system <NUM> is described as being particularly useful in localization of breast lesions, the system <NUM> may also be used in localization of other objects in other areas of the body.

Before the procedure, a target tissue region, e.g., a tumor or other lesion, may be identified using conventional methods. For example, a lesion (not shown) within a breast <NUM> may be identified, e.g., using mammography and/or other imaging, and a decision may be made to remove the lesion. The marker <NUM> may be implanted within the breast <NUM> within or adjacent the target lesion, e.g., using a needle or other delivery device, such as the delivery device <NUM> shown in <FIG>.

Once the marker(s) <NUM> is implanted, as shown in <FIG>, the probe <NUM> may be placed against a patient's skin, e.g., against the breast <NUM>. Signals from the antenna of the probe <NUM> may be delivered along with pulsed light from the light source to cause the switch <NUM> to open and close as the marker <NUM> receives and reflects the signals back to the probe <NUM>. If there is substantial clutter, crosstalk, or other noise being received by the probe <NUM>, e.g., due to the probe antennas, tissue or other structures within the patient's body near the marker <NUM>, and the like, the reflected signals from the two states (switch <NUM> open and closed) may be subtracted from one another, substantially eliminated the other noise, and allowing the probe <NUM> to identify and/or locate the marker <NUM>. Thus, the probe <NUM> may use the modulated reflected signals to increase the signal-to-noise ratio of the signals.

The display <NUM> may display information to the user to facilitate locating the marker <NUM> within the breast <NUM>. For example, the display <NUM> may simply be a readout providing distance, angle, orientation, and/or other data based on predetermined criteria, e.g., based on the relative distance from the marker <NUM> to the probe <NUM>. The distance information may be displayed as a numerical value representing the distance in units of length, such as in inches (in. ) or centimeters (cm). In addition or alternatively, a speaker <NUM> on the display unit <NUM> may produce an audible indication of distance, e.g., spaced-pulses that increase in speed as the probe <NUM> is closer to the marker <NUM>. In another alternative, the display <NUM> may present a graphical image (e.g., a two-dimensional or three-dimensional image) depicting the marker <NUM>, the probe <NUM>, the distance from the probe <NUM> to the marker <NUM>, and/or a physiological picture of the body part containing the marker (e.g., the breast).

For example, as shown in <FIG>, the distal end <NUM> of the probe <NUM> may be placed adjacent or in contact with the patient's skin, e.g., generally above the lesion, and/or otherwise aimed generally towards the lesion and marker <NUM>, and activated. The transmit antenna (not shown) of the probe <NUM> may emit electromagnetic signals 1034T that travel through the tissue and are reflected off of the marker <NUM>. Return signals 1034R may be reflected back to the receive antenna (not shown) in the probe <NUM>, which may then determine a spatial relationship between the marker <NUM> and the distal end <NUM> of the probe <NUM>, e.g., a distance and/or orientation angle, to facilitate determining a proper direction of dissection for the surgeon.

In addition, substantially simultaneously, the probe <NUM> may transmit light pulses 1038a, which may be received by the diodes <NUM> of the marker <NUM> (not shown, see, e.g., <FIG>). The diodes <NUM> may alternately generate a voltage, causing the switch <NUM> to open and close. This causes the marker <NUM> to change the phase of the signals reflected back to the probe <NUM>, which may process the signals, e.g., by subtraction, to identify and/or locate the marker <NUM>, and consequently the target lesion.

Tissue may then be dissected, e.g., by creating an incision in the patient's skin and dissecting intervening tissue to a desired depth, e.g., corresponding to a target margin around the lesion is reached. A tissue specimen may be excised or otherwise removed using conventional lumpectomy procedures, e.g., with the marker <NUM> remaining within the removed specimen <NUM>.

It will be appreciated that elements or components shown with any embodiment herein are exemplary for the specific embodiment and may be used on or in combination with other embodiments disclosed herein.

Claim 1:
A marker (<NUM>) sized for introduction into a target tissue region within a patient's body, comprising:
an energy converter (<NUM>) for transforming energy pulses striking the marker into electrical energy;
a switch (<NUM>) coupled to the energy converter such that the energy pulses cause the switch to open and close;
a pair of elongate wires (<NUM>) coupled to the switch to provide an antenna, the switch configured to open and close to modulate signals reflected by the antenna back to a source of the signals; the energy converter and the switch being encased or embedded in an electronics package (<NUM>),
wherein each wire includes a first end (44a) coupled to a printed circuit board or other circuit (<NUM>) within the package (<NUM>) and a second free end (44b),
characterized in that the marker (<NUM>) further comprises an electro static discharge (ESD) protection device (<NUM>) coupled to the switch to provide protection against an electrostatic discharge event, the electro static discharge protection device (<NUM>) being encased or embedded in the electronics package (<NUM>); and
in that the first ends include one or more bends to facilitate coupling the first ends to the switch such that the wires extend tangentially from opposite sides of the electronics package, wherein the wires extend tangentially from sides of the electronics package which are opposite to the sides of the printed circuit board or other circuit within the package to which each first end is coupled.