Patent ID: 12232861

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

Turning now to the figures in which like numerals represent like elements throughout the several views, in which exemplary embodiments of the disclosed techniques are described. For convenience, only some elements of the same group may be labeled with numerals.

The purpose of the drawings is to describe examples of embodiments and not for production purpose. Therefore, features shown in the figures are chosen for convenience and clarity of presentation only and are not necessarily shown to scale. Moreover, the language used in this disclosure has been principally selected for readability and instructional purposes, and may not have been selected to define or limit the inventive subject matter.

In this specification, these implementations, or any other form that the invention may take, may be referred to as techniques. In general, the order of the steps of disclosed processes may be altered within the scope of the invention. Reference in the specification to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least one embodiment of the invention, and multiple references to “one embodiment” or “an embodiment” should not be understood as necessarily all referring to the same embodiment.

In the following description, the words “unit,” “element,” “module”, and “logical module” may be used interchangeably. Anything designated as a unit or module may be a stand-alone unit or a specialized or integrated module. A unit or a module may be modular or have modular aspects allowing it to be easily removed and replaced with another similar unit or module. Each unit or module may be any one of, or any combination of, hardware configured to execute the task ascribed to the unit or module. In the present disclosure the terms task, method, and process can be used interchangeably. In addition, the terms element and section can be used interchangeably.

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 practiced 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.

The drawingsFIG.1A-1Cshow different views of an example embodiment of a transponder marker or tag100that may be implanted or placed within patient's body such as within a breast300as shown inFIG.3, for example by a delivery system like a needle assembly (not shown here). Generally, the marker100comprises a microchip110, including all electronic components, magnetic antenna120and internal part of microwave antenna130aenclosed into hermetic bio-compatible case140. The marker has additionally the external part130bof the microwave antenna. The components of the marker can be made of non-ferrite material and can be MRI compatible without a bloom artifact.

In an example embodiment, the magnetic antenna120may be a solenoid wired on a paramagnetic core like by not limited to glass. This antenna is tuned to the resonance frequency of an FCC approved for medical applications RF band of 13.56 MHz for the most efficient harvesting of electromagnetic energy irradiated by an excitation electromagnetic field pad320(seeFIG.3). The same magnetic antenna120structure can serve as a part (single arm) of the microwave dipole antenna150(FIG.1B) working at another FCC approved band of 5800 MHz. At this frequency, the wired layer of the magnetic antenna120can be thought of as a solid conducting cylinder due to the commonly known skin effect, in conjunction with the low-impedance RF path established by the turn-to-turn capacitive coupling between neighboring turns/loops of the magnetic antenna solenoid. This conducting cylinder together with the internal part130aof the dipole antenna and external part130bof the dipole antenna creates the half-wave resonant dual band antenna150.

In an example embodiment, the external part of the microwave antenna130bcan serve as an anchor preventing the migration of the marker after implantation/placement into soft tissues. The antenna can be comprised of memory metals. The antenna can be in the form of a spring or some other visually identifiable configuration. EIE's and VID's can be associated with the marker (not shown). The effect of self-anchoring can be improved by connecting two markers by their external parts, for example, by the connection of the130microwave antennas (seeFIG.2). The common connecting part of marker pair210can be built from bio-compatible metals like but not limited to tungsten or nitinol and can have spring properties. So-called memory metals can be used.

Assuming the activation of each marker is performed sequentially at different and independent time intervals, the marker electronics110activate the microwave antennas of each marker of the pair independently, without interference of operation of each marker of the pair. Different types of spring connections between marker pairs can be used depending on surgical requirements. The expandable pre-bent spring210acan be used for example in case of heterogeneous tissue. The fixed spring210bcan be used for example in case of homogeneous soft tissue.

In an example embodiment, the passive marker100is part of a system for localizing marker/s implanted within a patient's body, seeFIG.3. The system comprises the excitation electromagnetic (EM) field pad320, creating the EM field penetrating the volume of interest310, wherein the marker/s100have been previously implanted or placed. The system also comprises the remote hand-held locator330, and the tablet computer340providing general control and monitoring of entire system. The locator can also be machine, robotic endoscopically, laparoscopically etc operated.

In an example embodiment, the marker100harvests the electromagnetic energy within the volume310of the ROI from the external excitation field source pad320and simultaneously responds to the MW test signal emanating from the hand-held locator330. The signal (low-frequency carrier) generated by the pad320is modulated by a specific digital identification code. The process of ID activation of the marker can be achieved if and only if the code generated by the pad320matches the ID code stored in the selected marker's memory (within the chip110). The user selected marker100is made active and is enabled to respond to the test signal sent from the locator330.

InFIG.4, the external excitation field pad320creates an inductive field covering the volume of the region of interest310within the patient's body, providing enough energy for harvesting by a plurality of markers100within this volume. The signal has a carrier in the range of 13.56 MHz and is modulated by digital ID code using the binary-phase-shift-keying (BPSK) method.

Additionally, the carrier of this low-frequency RF signal is used as the synchronization signal in realizing the primary system function—coherent measurement of the selected marker's relative location (distance estimation). The BPSK modulation method provides maximum carrier signal power (maximum energy transference to the plurality of passive markers) and the simplest method of carrier recovery. This signal is received by magnetic antenna120of the marker (seeFIGS.1A,1B and1C) and is used by the passive marker for energy harvesting, ID demodulation, and decoding and generation of the MW response signal, which is triggered by reception of the MW test signal sent by the locator.

In the same example embodiment, the signal sent by the locator320and the response signal created by the marker100occupies the same FCC approved frequency band of 5800 MHz but have completely different spectra. For example, the test signal sent by the locator comprises two spectral components 5786.44 MHz and 5813.56 MHz, which represent balance modulated carrier of 5800 MHz by the first harmonic of the system synchronization signal of 13.56 MHz. The marker response is composed of the AM modulated signal having spectral components at 5772.98 MHz, 5800 MHz and 5827.12 MHz, which represent the carrier of 5800 MHz and two side-bands of the second harmonics of the synchronization signal (i.e., 27.12 MHz). This spectral difference allows using the excess energy harvested by the marker100, for the amplification of the response signal transmitted toward the locator330. The marker100uses the resonant half-wave dipole (microwave antenna)150for transponding interactions with the locator330. Both antenna, one for energy harvesting and another for microwave interactions are combined in a dual-band antenna surrounding the marker electronics.

In the same exemplary embodiment, the Tablet computer340provides pre-operational monitoring and control of the hand-held locator330and the pad320by using the standard Bluetooth interface and protocol. During the surgery the hand-held locator330performs the phase measurements between the synchronization signal coming from the pad320and the response signal coming from the marker100which fundamentally encodes information about the distance between the locator330and the marker100. Additionally, the locator measures the 3D acceleration of its movements (gliding) over the surface of the patient's skin. All this information is transferred to the computer340via Bluetooth IF for estimation of the plurality of marker locations.

In an example embodiment, the functional block diagram of the excitation electromagnetic field source pad320is illustrated in theFIG.5. According to previous art (“Optimization of output power and transmission efficiency of magnetically coupled resonance wireless power transfer system” by R. Yan, X. Guo, S. Cao and C. Zhang, on-line published 2 Jan. 2018), the power transferred by a wireless coupled magnetic resonance system is proportional to the square of the radius of used coils. To fit within the confines of the small hand-held locator device, the prior art RF markers mentioned above use antennas with diameters less than 30 mm to excite the markers. The currently disclosed embodiment uses magnetic antenna512in the excitation pad of diameter (for example) 500 mm allowing significant (more than 270 times) amplification of the energy harvesting potential without modifying the marker geometry.

In such embodiment, the local controller502of the pad320receives via the Bluetooth link503(after the process of pairing) information regarding the one or more implanted markers within the region of interest. During each marker localization event in time, the local controller502commands the code sequence generator504to create a code sequence corresponding to the currently active code ID from the list stored in its memory. The code can be changed via a user-issued command into the tablet computer340(seeFIG.4). The code sequence is used as input by BPSK modulator506which modulates the carrier of the synchronization signal generated by crystal-controlled oscillator508. The modulated signal is amplified by output power amplifier510and transmitted into the patient's body via magnetic loop antenna512. This antenna generates the electromagnetic near-field which resonantly couples (via magnetic induction) to the plurality of markers' on-board magnetic antennas, ultimately providing operational power to the markers.

In an example embodiment, the functional block diagram of the microchip110(seeFIGS.1A,1B and1C) is illustrated inFIG.6. This system-on-chip device can be a modification of an existing RFID chip, such as NTAG203 NFC (cdn-shop.adafruit.com/productfiles/4034/P4034_datasheet_NTAG_203.pdf). The blocks from602to612perform standard operations of the RFID system. The rectifier/local power supply602receives the signal from the markers magnetic antenna120and provides power supply energy for all electronic components of the marker100. The AC components of this signal are used for PLL (phase-lock loop)606tuned to the carrier frequency of the receiving signal (low-frequency synchronization signal) and code demodulator604. The output of this demodulator represents the code time sequence envelope similar to that generated by504(seeFIG.5). This signal is sampled by the local ND convertor608and in digital form is transferred to the local Processor/Correlator610.

The correlator610uses the marker specific code ID stored in its memory612for decoding the processing code time sequence. In case of successful decoding (ID code match), the “code coincidence enable” signal is generated by the processor610. The example embodiment of the chip extensions are represented by blocks614,616and618. The active circulator616(see previous art: “A 60 GHz Analog Phase Shifter in 65 nm Bulk CMOS Process” by S. Harrison, Z. Ping, IJCNC July 2010) receives the MW test signal coming from the hand-held locator330. This signal has two spectral components of 5786.44 MHz and 5813.56 MHz of the FCC-permitted band 5800 MHz. These components are amplified by RF (LNA) amplifier618and are relayed to the Double-Balance Modulator614.

In the case of a successful ID code match, the code coincidence enable signal generated by correlator610activates the modulator614to modulate (mathematical analog multiplication) the amplified MW signal received from the locator with the low-frequency AC signal coming from the pad. The result of this modulation is a signal having three spectral components in the 5800 MHz band, i.e., 5772.88 MHz, 5800 MHz and 5827.12 MHz. This signal is sent to the active circulator616and then transmitted via the same dipole antenna150of the marker. The spectral difference between the received and the transmitted signals prevent parasitic oscillations in RF Amplifier618.

In the example embodiment of the marker localization, the functional block-diagram of the locator330is illustrated inFIG.7. The locator receives the synchronization signal from the pad320via magnetic antenna702. This signal is passed to the carrier recovery circuitry to create a signal in the 13.56 MHz band, which is then used in generating the marker interrogation test signal. The pad signal ultimately serves as a reference signal for the phase difference estimation. The generation of the marker interrogation test signal is performed by modulation of the 5800 MHz carrier produced by oscillator708with the low-frequency 13.56 MHz signal coming from the carrier recovery circuit704(received from the pad320).

The result of the Double-balance modulation706is a signal with two spectral components, occupying the 5786.44 MHz and 5813.56 MHz sub-bands. This signal is amplified by RF amplifier710and transmitted into the patient's body (toward the one or more implanted markers) via circulator712and microwave antenna714. The same antenna714is used for receiving the active marker response. This response (microwave signal) contains 3 spectral components (i.e., 5772.88 MHz, 5800 MHz and 5827.12 MHz). This signal can be thought of as an amplitude modulated (AM) signal, with a modulating (envelope) waveform provided by the second harmonic of the synchronization signal 13.56 MHz. The modulation function is detected by detector715, and passed through the band-pass-filter (BPF). The BPF is tuned to the required modulation function of 27.12 MHz (second harmonic of the synchronization signal 13.56 MHz). This modulation function contains the “there-and-back” (double-propagation) delay information associated with the microwave signals (centered at 5800 MHz) relayed from the locator320to the marker100and returned as a different, “response” signal. Accordingly, the harmonic signal at 27.12 MHz contains a scaled copy of the phase shift information (relative to some reference signal) of the fundamental frequency (13.56 MHz) signal.

Turning to theFIG.7. In a “there-and-back”, double propagation of the MW signal through (for example) 100 mm of human tissue, the harmonic signal of 27.12 MHz (detected by detector715) does not vary more than 12 Deg in phase. This low measure of phase shift can be significantly increased through the employment of higher harmonics, created from the signals designated for the phase comparison. The pre-distorters716and718can be used for this harmonic signal generation, acting on the modulation envelope of the MW response and the RF synchronization signals, respectively. Using the 5th harmonic of the 27.12 MHz modulation envelope and the 10thharmonic of the synchronization signal at 13.56 MHz permits phase comparison at 135.6 MHz, significantly improving the dynamic range of the phase detector720.

The result of the phase different measurement is digitized by ND722and passed to the local controller724. Simultaneously, the local controller724accepts the information regarding the position of the locator on the skin surface from the XYZ-Accelerometer726. All this real-time information is transferred to the tablet computer340via Bluetooth interface728. Additionally, in the same embodiment, the local controller724can receive (through the Bluetooth interface) feedback information from the tablet computer340about the correct “locator search” direction for the currently selected/active marker. This information can be displayed, for example, by means of some LED array indicator730deployed for example around the tip of the hand-held locator330.

In this example embodiment, the processor or tablet computer340can perform the following functions:1. Initiate and orchestrate the creation/editing subroutines needed to populate the marker pre-implantation database, including barcode scanning of the marker packages;2. Conduct pre-operation system tests (check and verification of all system components, i.e., pad320and locator330). These tests can significantly improve readiness of the system;3. Perform real-time control of the system for successful localization of one or more markers during the surgical procedure(s);4. Process and analyze the results of the localization process (stored in the database) post-surgery.

The processing unit340can be a personal computer, tablet computer, personal digital assistant (PDA), smartphone, or similar portable device. These terms can be used interchangeably and the term tablet will be used as a representative term for this group. An example of a tablet computer340can be an iPad manufactured by Apple Computers. Alternatively, the tablet340can be based on the Android operating system. The tablet340can be controlled via its touch-screen and may operate in several modes.

Tablet340may execute a plurality of software programs associated with the marker localization system/process. The programs can be used to control the system, to guide the surgeon towards a relevant marker100, and to calculate the distance from each implanted marker to the locator330, in real time. In addition, the tablet can be used as a man-machine interface (MMI) for communicating with the surgeon, via audio signal and 2D visual display, etc. Some examples of the software programs are disclosed below in conjunction withFIG.8-11. The tablet340can communicate with the pad320and the locator330via the Bluetooth communication protocol and hardware stacks. The system is not limited to detecting a finite number of markers. For example, six or more (as an arbitrary number) markers coexisting within an anatomical body of tissue can be simultaneously processed and detected by the system.

FIG.8illustrates a flowchart800showing relevant processes that can be implemented during a pre-operation (i.e., pre-surgical) task. Upon initiation802of the pre-operation task, the tablet340(FIG.3) can prompt the operator804to enter the patient data. The data may include identification and medical details about the patient, information about the surgery, the number of markers to be used, the unique electronic and the unique collective ID of each marker, the ROI, etc.

Next, the operator may plan806the surgery. By placing a diagram of the ROI (for that patient, for that particular procedure) on the tablet screen, the operator may determine where to implant/place each of the markers and accordingly may place806an image of each marker in the appropriate location related to the image of the ROI generating an implant-schema.

Once the implant schema is complete, a loop from block810to822can be started. Each cycle in the loop can be associated with one of the markers that appears in the implant-scheme. At block810, a first marker is fetched and its barcode or QR, which constitutes the marker ID, can be scanned812by a camera of the tablet. Then the scanned ID can be associated with the ID of the diagram of the relevant marker in the implant-schema and the association of the two IDs can be stored814in a pre-operation DB. The marker can then be placed or implanted (not shown here). It should be noted that the term implantation is used generally and is understood to include placement, attachment etc. of the marker to tissue by any means. The placement of the markers can be via an introducer needle with a plunger whereby single, multiple or sequential markers can be placed at one time. The placement (and detection/localization) of markers can be via an endoscope, laparoscope, robot or video assisted device etc.

Next, a decision is made820whether further markers require implantation. If820further markers require implantation, then the next marker can be fetched822and process800loops back to block812. If820there are no additional markers, then at block824process800can be configured to update the implant-scheme with the ID of the relevant deployed markers. The updated implant-schema with the scanned ID of the markers can be referred to as the Marker-Localization schema and be stored in the DB, to be used for locating the markers and ROI during the surgery. Then process800can be terminated830.

In some potential embodiments of the disclosed technique, the marker-localization schema may comprise an image of the ROI and the location of each marker around the ROI, wherein each marker is presented with its own unique ID. Further, the schema may diagrammatically present the relative orientation and distance between the markers. In some embodiments the schema may include the order of suggested marker localization, for example to start by localizing marker ID #3, and thereafter marker ID #5, etc. Furthermore, some example embodiments of the disclosed technique may present a 3D rendered image on the display of the tablet340(FIG.3), which can be rotated according to the corresponding movement(s) of the locator330(FIG.3).

Referring now toFIG.9which illustrates a flowchart900showing relevant processes that can be implemented upon starting902the system for delineating the position of a specific marker/s and hence the ROI within a body tissue. In block902, two counters, which participate in this process, can be reset. At block904the tablet340(FIG.3) can be associated with the pad320(FIG.3) through the pairing process provided by the Bluetooth protocol/chipset. At block906a Bluetooth channel with the EM pad320can be opened.

Next, the tablet340can instruct the excitation pad320to execute908the self-test of the pad. At the end of the self-test, a decision is made910whether the self-test was successfully performed. If910no, then a first counter, which counts the number of attempts, can be incremented912by one and a decision is made914whether the number of attempts is more than ‘N’ attempts. Typically, ‘N’ can be an integer number between three to five three, for example. If914the number of attempts is not more than ‘N’, then process900returns to block804.

If914the number of attempts is more than ‘N’, then process900may proceed to block936and inform the surgeon that the system configuration/set-up has failed and process900can be terminated. Some embodiments of the disclosed technique may display the failed elements/subsystems detected within the pad320(FIG.3).

Returning now to block910, If910the self-test of the pad was successfully performed and completed, then locator330(FIG.3) can execute its own self-test. At block920, the tablet340(FIG.3) can be associated with the locator330(FIG.3) through the pairing process provided by the Bluetooth protocol/chipset. At block922a Bluetooth channel with the locator330can be opened.

At the end924of the self-test, a decision is made930whether the self-test was successfully performed. If930no, then a second counter, which counts the number of attempts, can be incremented932by one and a decision is made934whether the number of attempts is more than ‘M’ attempts. Typically, ‘M’ can be an integer number between three to five, four, for example. If934the number of attempts is not more than ‘M’, then process900returns to block920.

If934the number of attempts is more than ‘M’, then process900may proceed to block936and inform the surgeon that the system configuration/set-up has failed and process900can be terminated940. Some embodiments of the disclosed technique may flag the locator330(FIG.3) as the failed element. Returning now to block930, If930the self-test of the locator was successfully completed, then a message can be displayed on the tablet938informing the surgeon that the self-test of the system was successfully executed and process900can be terminated940.

FIG.10illustrates a flowchart showing relevant processes that can be implemented prior to and during an operation, for an example method1000employed to guide a surgeon to one or more implanted markers. Upon initiation1002the method1000may fetch1004the Marker-Localization-schema (from Surgery Plan DB), relevant to the current operation. Based on the Marker-Localization-schema, the ID of the first marker is fetched1006and appears on the tablet screen. Next, at block1006the tablet340(FIG.3) may instruct, via Bluetooth, the pad320(FIG.3) to emit an excitation electromagnetic field310(FIG.3) within the 13.56 MHz band permeating the ROI of the patient300(FIG.3). The electromagnetic field310can be BPSK modulated, wherein the modulation reflects the ID of the relevant marker100(FIG.3), thus activating only the relevant marker. Simultaneously, the locator330transmits a MW test signal, receives a MW response signal from the activated marker100and performs the phase difference measurement.

The Tablet computer340receives the Phase/Frequency Data1008from the Locator and calculates the distance1010between the active marker and the locator. The value of the phase difference and corresponding calculated distance of this specified marker together with the Real-Time Clock Marks is saved (accumulated) in appropriate files of the database1009. After some predetermined number of marker distance estimates, data will be accumulated in the file allocated for specific marker measurements, and the routine1100(Marker direction estimation program) can be initiated. Simultaneously the estimated distance and active marker ID can be displayed1012on the computer340screen by means of the Tablet-on-screen MMI and the Tablet-generated audio signal1014can change its pitch. If the marker-change-interrupt1016has not been received the marker localization process can be continued.

Next, a decision is made whether1016a marker-change-interrupt was received from the locator. If1016no, method1000returns to block1008for calculating the current distance between the locator and the relevant marker. If1016yes, then a decision is made1018whether there are more markers in the marker-localization-scheme. If1018yes, then the ID of the next marker in the marker-localization-scheme is fetched1006and method1000returns to block1006for handling the next marker. If1018there are no more markers in the marker-localization-scheme, then method1000can be terminated.

In the embodiment currently disclosed,FIG.11illustrates an example marker direction estimation program1100of the tablet computer340. The program can be initiated automatically or by some method of instruction pre-programming. In an automatic regime, after accumulating some data (i.e., some specified value) in marker distance file1112, the computer begins accumulating the XYZ-accelerometer data1102from the locator330. After double integration in time1104, this data is stored in temporary memory1106as a trajectory of the locator330movement on the surface of the patient's skin. After time-smoothing the trajectory data by the filter1108, the spatial gradient1110of the trajectory is calculated. This gradient is compared with the result of the distance derivative calculation1114by means of the distance change correlator1116. If the gradient and distance change are correlated, the decision about correct direction1118is accepted. Next, the tentative 3D position of the active marker can be calculated1120. The result of “correct direction” angle (based on attitudes provided by gradient calculation1110) is transferred to the locator330via the Bluetooth interface. This direction can be displayed by using the LED array indicator730(FIG.7). The indication of the “correct” direction to the active marker can guide the surgeon to moving the locator330in expediting localization of the active marker100. The localization information belonging to the active marker, for example; the current locator to marker distance; marker ID; direction to the marker; can be displayed on the screen of the tablet computer340.

Turning toFIG.4, a schematic of potential RF and MW signal paths is shown for estimating the distance from the marker100to the locator330. Assuming the current distance from the center of the excitation (and synchronization) pad320and locator330as R0, distance from the center of pad320to the marker100as R1, and the distance from the marker100and the locator330as D, the complex amplitudes of the signals received by the marker100and the locator330can be presented as the following: Sm=A1exp(−i2πR1/λ1) and SL=A0exp(−i2πR0/λ1) respectively, where λ1is a wavelength of propagating the frequency band of 13.56 MHz in the patient's body310.

The signal transmitted by the locator330toward a plurality of markers has the following spectral components:
ST=ALexp(i(ω2+ω1)t)exp(−i2πR0/λ1)+ALexp(i(ω2−ω1)t)exp(−i2πR0/λ1),
where ω2and ω1are angular frequencies of the bands 5800 MHz and 13.56 MHz respectively. The signal responded by the active marker and received by the locator's microwave antenna has three spectral components: ω2, ω2+2ω1, and ω2−2ω1. After amplitude detection715(FIG.7) and band pass filtering which is tuned to 27.12 MHz band (2ω1frequency) the low frequency signal is proportional to cos(2ω1(t−2D/v2−R0/v1), where v2and v1are velocities of the EM wave propagation in tissue for frequencies of ω2and ω1respectively. The phase difference measured by phase detector720(FIG.7) allows the distance estimation according to the formula D=Δϕλ1/(2π√ε2), where ε2is the permittivity of human tissue (for example breast tissue) and Δϕ is the phase difference measured by the phase detector720.

The described algorithm provides an estimation of the distance between the locator330(FIG.3) and the active marker100in the case where the center of the reference (EM field excitation) pad, activated marker and locator all reside on the same direct line (the co-axial case).

The marker can be placed at any location within the volume of tissue310(seeFIG.3) irradiated by the pad320. There can be instances of initial, non-zero (axial) distance and (lateral) offset of the marker relative to the center of the excitation pad. In such instances, in the initial localization process, there can be a large initial distance between the locator and the active marker. During the interactive process of marker localization, as the surgeon moves the locator toward the active marker, the distance discrepancy converges to zero. This process of zero convergence can be represented on the computer screen340as a series of concentric circles converging to a dot on the screen as and when the locator reaches a site directly over the active marker.

In the description and claims of the present disclosure, each of the verbs, “comprise”, “include”, “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements, or parts of the subject or subjects of the verb.

The present disclosure has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the present invention utilize only some of the features or possible combinations of the features. Many other ramification and variations are possible within the teaching of the embodiments comprising different combinations of features noted in the described embodiments.

It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described herein above. Rather the scope of the invention is defined by the claims that follow.