WO2021041183A1 - Systems, apparatuses, and methods for monitoring tissue ablation - Google Patents

Abstract

A device for sensing an electrical parameter may comprise a sensing element configured to be in electrical series between a generator and an ablation probe. The sensing element may be configured to measure at least one of a current or a voltage being delivered from the generator to the ablation probe.

Description

SYSTEMS, APPARATUSES, AND METHODS FOR MONITORING TISSUE

ABLATION

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority from U.S. Provisional Application No. 62/890,870, filed on August 23, 2019, which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates generally to systems, apparatuses, and methods for monitoring and/or tissue ablation and, in particular, to monitoring and/or controlling ablative energy.

BACKGROUND

[0003] Techniques such as radio frequency ablation may be used to deliver energy to tissue, thereby ablating it. Users of ablation devices may desire information regarding progress of ablation in a subject. Such information may be helpful in determining when to modify or discontinue an ablation procedure. However, existing devices do not provide adequate information to a user. Therefore, a need exists for systems, apparatuses and methods for monitoring ablation.

SUMMARY

[0004] A device for sensing an electrical parameter may comprise a sensing element configured to be in electrical series between a generator and an ablation probe. The sensing element may be configured to measure at least one of a current or a voltage being delivered from the generator to the ablation probe.

[0005] Any of the devices disclosed herein may have any of the following features. The sensing element may be configured to be removably connected to the generator and the ablation probe. An output of the sensing element may be an analog energy signal. The generator may be an RF generator. The sensing element may be contained within the ablation probe. A control element may be configured to adjust a flow of energy from the generator to the ablation probe. The control element may be configured to adjust the flow of energy to the ablation probe using a signal output by the sensing element. The control element may be configured to compare the signal output to a reference value. The control element may be configured to stop the flow of energy when the comparison of the signal output to the reference value satisfies a predetermined condition. A processor may be configured to provide information on a display regarding a depth of tissue ablation, an amount of energy delivered, or an amount of powered delivered. The sensing element may be configured to measure the at least one of the current or the voltage being delivered to a first region of the ablation probe and to measure the at least one of the current or the voltage through a second region of the ablation probe. A processor may be configured to provide information on a display regarding a first energy level delivered to the first region of the ablation probe and a second energy level delivered to the second region of the ablation probe. The processor may be configured to use the first energy level to determine a first depth of tissue ablation in a first tissue region and the second energy level to determine a second depth of tissue ablation in a second tissue region. The generator may be a radiofrequency generator, and wherein the ablation probe includes at least one bipolar electrode. The sensing element may include a transducer. A processor may be configured to use the at least one of the current or the voltage to determine an energy level delivered to the ablation probe and to use the energy level to determine a depth of tissue ablation.

[0006] In another example, a device for sensing an electrical parameter may comprise a sensing element configured to be electrically connected to an ablation probe. The ablation probe may include at least one electrode. The sensing element may be configured to measure at least one of a current or a voltage through the electrode and to output a signal representing an energy delivered by the electrode. The device may further comprise a processor configured to use the signal to determine a depth of tissue ablation.

[0007] Any of the devices disclosed herein may have any of the following features. The sensing element may be further configured to be in electrical series with the ablation probe and a generator. The sensing element may be configured to be removably connected to the ablation probe and the generator.

[0008] A method for monitoring tissue ablation may comprise receiving information from a sensing element pertaining to an energy delivered to an ablation probe. The sensing element may be configured to measure at least one of a current or a voltage of the energy. Using the received information, at least one of a representation of energy delivered versus time, a total amount of energy delivered, or an indication of a depth of tissue ablation may be displayed.

[0009] Any of the methods disclosed herein may include any of the following steps or features. The method may further comprise automatically adjusting the energy delivered to the ablation probe.

[0010] It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example,” rather than “ideal.” As used herein, the term “proximal” means a direction closer to an operator and the term “distal” means a direction further from an operator. Although radio frequency (“RF”) ablation is referenced herein, such references should not be construed as limiting. The examples disclosed herein may also be used with other types of ablation mechanisms (e.g., cryoablation, vapor ablation, or other types of ablation) or with other energy delivery devices not relating to ablation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate examples of the present disclosure and together with the description, serve to explain the principles of the disclosure.

[0012] FIGS. 1A and 1 B depict exemplary systems for measuring, displaying, illustrating, and/or monitoring ablation energy.

[0013] FIG. 2 depicts an exemplary probe for use with the disclosed systems for measuring ablation energy.

[0014] FIG. 3 is a chart relating maximum ablation depth to total energy input.

[0015] FIG. 4A depicts another exemplary system for measuring ablation energy.

[0016] FIGS. 4B-4C are block diagrams showing relationships between components of the exemplary system of FIG. 4A.

[0017] FIG. 4D depicts an exemplary control element for use with the system of FIG. 4A.

[0018] FIGS. 5A-5B depict a system configured for directional measurement of energy input. [0019] FIG. 6 depicts the system of FIGS. 5A and 5B in a body lumen of a subject.

[0020] FIG. 7 depicts an exemplary sensing element for use with the systems disclosed herein.

DETAILED DESCRIPTION

[0021] Systems, apparatuses, and methods disclosed herein may include use of one or more sensing elements electrically and/or physically connected to a generator and an ablation probe. The sensing elements may measure an energy delivered by the probe. Delivered energy levels may correlate to a depth of tissue ablation. Such systems may enable closed-loop control of the generator and/or the probe. In one example, a sensing element may be housed within the probe itself. Sensing elements, whether internal or external to the probe, may be capable of measuring energy emitted from different regions of the probe. The sensing element may be used with an off-the-shelf generator without requiring modification of the generator. Alternatively, the sensing element may be contained within the generator’s hardware/software.

[0022] FIGS. 1A and 1 B show exemplary systems 10 for measuring energy delivered to or by an ablation probe. A system 10 may include one or more probes 11 , which may include one or more electrode arrays 12 having one or more electrodes. The probe 11 and/or electrode array 12 may have any suitable configuration. For example, the electrodes of electrode array 12 may be bipolar. Alternatively, the electrodes may be monopolar. FIG. 1A shows a system 10 having one probe 11 with one electrode array 12, and FIG. 1 B shows a system 10 having one probe 11 with a plurality of electrode arrays 12. While FIG. 1B shows four electrode arrays 12, that number is merely exemplary. Any suitable number of electrode arrays 12 may be used. Multiple probes 11 may also be used. Probe 11 may include, for example, a catheter device configured to be inserted into a body lumen of a subject.

[0023] System 10 may also include a generator 14, which may generate energy to be used by electrode array 12. For example, generator 14 may generate RF energy. Generator 14 may alternatively produce energy to cool or heat fluids used in ablation by probe 11. Generator 14 may be a general-purpose generator that may be used with a variety of applications and is not limited to use with probe 11. Generator 14 may be electrically and/or physically connected to electrode array 12 via one or more connections 16, which may include one or more supply lines. For example, connection 16 may include a positive voltage line 18 and a negative voltage line 20, each of which may be electrically and/or physically connected to generator 14 and electrode array 12, either directly or indirectly. Positive voltage line 18 and negative voltage line 20 are not shown separately in FIG. 1 B for ease of illustration; however, it will be appreciated that connection 16 may incorporate such components.

[0024] System 10 may further include a sensing element 22. Further details of sensing element 22 will be provided below. Sensing element 22 may be electrically and/or physically connected between generator 14 and electrode array 12. For example, as shown in FIGS. 1A and 1B, sensing element 22 may be electrically connected in series with electrode array 12 and generator 14. Alternatively, energy sensing element 22 may be electrically connected to electrode array 12 and/or generator 14 using other configurations (e.g., a parallel connection). Sensing element 22 may be removably connected to probe 11 and/or generator 14, so that probe 11 and/or generator 14 may be used off-the shelf with sensing element 22. Sensing element 22 and generator 14 may be configured so that generator 14 is a capital device that does not need to be modified for use with sensing element 12 and sensing element 12 is a plug-and-use device.

[0025] Sensing element 22 may measure and/or record voltage and/or current traveling through and/or delivered by probe 11 , including through electrode array(s) 12 of probe 11. For example, sensing element 22 may be a passive element (e.g., a two-terminal device with no power applied) or an active element (e.g., a powered sensor integrated circuit configured to take measurements. Sensing element 22 may include multiple components. For example, a current probe (which may be an active sensor) may be used along with an electrical impedance spectrometer device (which may also be an active sensor that monitors current delivered to tissue and an impedance of the tissue). Sensing element 22 may also include a temperature sensor (e.g., an active sensor such as an infrared sensor). Using voltage and current measurements, other information may be calculated (or approximated), such as power, power as a function of time, total energy, and/or total system impedance. For example, system 10 may include a processor (not shown), which may perform calculations based on data obtained from sensing element 22. A processor used in conjunction with sensing element 22 may also perform other functions with respect to generator 14, probe 11 , or other components of system 10. Generator 14 may include a processor capable of performing such calculations. A processor performing such calculations may be included on a micro-controller in or separate from sensing element 22. A processor may be connected to a display 26 or contained in the same device as display 26. A processor may utilize operating parameters of any portion of system 10 (e.g., power/impedence measurements of portions or an entirety of system 10). [0026] Information regarding measurements and/or calculations obtained by or derived from sensing element 22 may be displayed on display 26. Display 26 may include information regarding a status of probe 11 and/or, electrode array 12, and/or progress of ablation. For example, display 26 may display information including total energy delivered over time, present energy level, present current level, and/or current voltage level. Display 26 may display such information in any suitable format, including a table, a graph, a graphical representation, a list, a present value, a color coding, another type of representation, or a combination thereof. For example, display 26 may display a graph of energy delivered versus time. Display 26 may also display information regarding a depth of tissue ablation, the determination of which will be discussed below with regard to FIG. 3. For example, display 26 may use a color-coded system, wherein colors shown on display 26 provide information regarding progress or status of ablation. For example, a green color may indicate to a user to continue ablation, a yellow color may indicate that ablation is nearing completion, and a red color may indicate to a user that ablation is complete. Display 26 may convey information at varying levels of granularity (e.g., overall status, as well as particular measurements) at the same or at different times. Display 26 may be interactive so that a user may customize the content of display 26 either before a procedure or dynamically as a procedure is performed.

[0027] FIG. 2 shows an alternative probe 50 that may be used in conjunction with system 10. Probe 50 may be substantially cylindrical extending along a longitudinal axis, and in some embodiments may be a balloon, e.g., formed of a non- compliant material. Probe 50 may include one or more sensing elements 52 integrated into electrode arrays 54 of probe 50. In FIG. 2, sensing elements 52 are shown at a distal end of electrode arrays 54, though sensing elements 54 may be located at any position on probe 50. Sensing elements 52 may form a portion of electrode arrays 54 or may be separate from electrode arrays within probe 50. Sensing element 52 may be contained within probe 50. Probe 50 may otherwise have any of the properties of probe 11 , described above, and electrode arrays 54 may have any of the properties of electrode arrays 12. Sensing element 52 may include any of the features of sensing element 22. Whereas sensing element 22 may be external to electrode arrays 12 (or housed elsewhere on probe 11 but not as a portion of electrode arrays 12), sensing element 52 may be incorporated into electrode arrays 54 or other portions of probe 50. Thus, probe 50 may be used in conjunction with generator 14 (or another energy source) without a separate sensing element 52 connected between generator 14 and probe 50. Probe 50 may also be used in conjunction with other aspects of system 10, including display 26, and the calculations and feedback mechanisms described herein apply both to probe 50 and to the combination of probe 11 and sensing element 52.

[0028] Arrays 54 may extend from a proximal end of probe 50 toward a distal end of probe 50. Arrays 54 may include numerous electrodes, which may be bipolar electrodes. Multiple arrays may extend around a circumference of probe 50. Sensing element 52 may have a position on array 54 that would otherwise house an electrode. Each array 54 may include one sensing element 52 or multiple sensing elements 52. It is understood that the arrays 54 including one or more sensing elements 52 may be any pattern, and may be uniformly distributed about the circumference of probe 50, or may be concentrated in a selected portion of probe 50. In this manner, probe 50 may have a desired pattern for a selected treatment of tissue. It is also understood that energy may be selectively applied to desired arrays

54 for tissue treatment. [0029] A measured or calculated energy delivered by electrode array(s) 12 and/or 54 may provide information regarding a depth or volume of tissue ablated in a subject. For example, FIG. 3 shows exemplary data regarding a relationship between a total energy (in Joules) input by probe(s) (such as probes 11 or 50 or the other probes disclosed herein) and a maximum depth (in millimeters) of tissue ablated. A total energy may measure the energy delivered into the tissue. Probe 11 and/or electrode array 12 may be configured to measure an impedance (e.g., using an active sensor) of tissue and to provide data regarding changes in impedance over time.

[0030] FIG. 3 shows measurements taken over a number of ex vivo ablations. As shown in FIG. 3, total energy input and maximum ablation depth may have a general linear relationship. A fit line for a relationship between energy input and depth of ablation may vary somewhat depending on the type of tissue targeted (e.g., upper gastrointestinal tract vs. lower gastrointestinal tract). Flowever, generally, a relationship between energy input and depth of ablation may be nearly the same (or the same), regardless of the type of tissue targeted. Therefore, information regarding energy input may be indicative to a user of system 10 as to a depth of tissue ablation by probe 11 or 50. The data of FIG. 3 is merely exemplary. Other relationships between measurements from probe 11 or 50 and/or electrode array 12 or 54 may be used in order to obtain information regarding progress of ablation. Alternative relationships, aside from the exemplary linear relationship shown in FIG.

3, may also be utilized. Algorithms pertaining to relationships between energy delivered and depth of ablation may be stored on a processor, such as the processor discussed above or may be embedded in a microcontroller. Such algorithms may account for energy levels (such as the measurements obtained from sensing element 22 or sensing element 52), tissue type, patient characteristics, probe type, intended results of ablation, etc. In a closed-loop system, such as those described below with respect to FIGS. 4A-4D, outputs from generator 14 and/or probe 11 may be adjusted based on the algorithm.

[0031] Data from sensing element 22 may also provide a user with information regarding a status of a probe 11 and/or electrode array 12. An ablation treatment may consist of numerous ablation cycles and may be conducted in multiple locations without removing ablation probe 11 from a subject’s body lumen. During an ablation treatment, tissue char and/or coagulum may build up on probe 11. Such build-up may decrease performance of probe 11 over time. For example, power delivered by probe 11/electrode array 12 may decrease or drop off over time. For example, ablation energy may be relatively consistent until an energy drop off occurs after a particular number of ablations, which may depend upon a subject, a device, a type of tissue, an amount of energy delivered, or other parameters. As an example, ablation energy may drop off between a fifth ablation and a tenth ablation. Sensing element 22 may detect such an energy decrease, and display 26 or another device may convey such information to a user. Based on a communicated decrease in ablation energy, a user may decide to remove ablation probe 11 from a subject for cleaning or replacement prior to further ablation.

[0032] As shown in FIGS. 4A-4C, the systems described herein may include functionality to control the energy delivered via a probe (such as probe 11 or 50 or the probes described below) based on information obtained from a sensing element (such as sensing element 22 or 52). System 100, showed in FIG. 4A, may be a closed-loop system. System 100 may have any of the features of system 10, described above. System 100 may include a generator 114, one or more probes 111 having one or more electrode arrays 112, a sensing element 122, and a control element 130. Although generator 114, probe 111, sensing element 122, and control element 130 are depicted in FIG. 4A as separate elements, they may be combined with one another. For example, sensing element 122 and electrode array 112 may be housed together in probe 111, as discussed above with respect to FIG. 2, or control element 130 and sensing element 122 may be housed in one component. Generator 114 may integrate sensing element 122 and/or control element 130. Sensing element 122 may be arranged in any of the manners described above with respect to FIGS. 1A, 1B, and 2. Control element 130 may be connected to sensing element 122 and to at least one of generator 114 and electrode array 112.

[0033] FIGS. 4B and 4C are block diagrams of exemplary configurations of system 100. The configurations shown in FIGS. 4B and 4C are merely exemplary, and any suitable configuration may be used to achieve the outcomes described herein.

[0034] For example, in a first configuration 160, as shown in FIG. 4B, probe 111 may transmit information to sensing element 122 regarding operation parameters of electrode array 112, such as those discussed above with respect to probes 11 and/or 50 (e.g., current, voltage, impedance, and/or other types of data). Sensing element 122 may transmit information, including the information received from probe 111 , to control element 130. Control element 130 may determine appropriate parameters for energy delivered by electrode array 112. Control element 130 may be in communication with generator 114 and may receive energy (e.g., current, voltage, impedance and/or other types of data) from generator 114. Control element 130 (or another component) may determine that the energy parameters should be adjusted based on the determinations by control element 130 and may determine appropriate energy levels. The determined energy may then be transmitted to electrode array 112, from control element 130. Additionally or alternatively, control element 130 may provide information to generator 114. The arrow from control element 130 to generator 114 is dashed so as to indicate that such a communication path is an additional or alternative path. In such a case, generator 114 may then adjust an energy level based on the determination by control element 130 and provide that adjusted energy to electrode array 112 via control element 130 and/or directly to electrode array 112 (see dashed arrow from generator 114 to probe 111).

[0035] FIG. 4C shows an alternative configuration 170 of system 100. As shown in FIG. 4C, sensing element 122 may receive information from probe 111 regarding operation parameters of electrode array 112 (e.g., current, voltage, impedance, and/or other types of data). Sensing element 122 may be in communication with control element 130 so that control element 130 obtains information from probe 111 via sensing element 122. Based on the information received from sensing element 122, including a signal received from sensing element 122, control element 130 may determine energy levels to probe 111 and may determine an appropriate energy level to deliver to probe 111 (including, e.g., a current and/or voltage). Control element 130 may be in communication with generator 114 and may receive energy (e.g., current and voltage) from generator 114. The determined energy may then be transmitted to sensing element 122, and from sensing element 122 to probe 111. Additionally or alternatively, control element 130 may provide information to generator 114. The arrow from control element 130 to generator 114 is dashed so as to indicate that such a communication path is an additional or alternative path. Generator 114 may then adjust an energy level based on the determination by control element 130 and provide that adjusted energy to probe 111 via control element 130 and/or directly to probe 111 (see dashed arrow from generator 114 to probe 111).

[0036] FIG. 4D illustrates an exemplary control/sensing element 200, which may have any of the properties of control element 130, described above. Control/sensing element 200 is merely one example and various configurations may be used. Control/sensing element 200 may be in communication with a probe 211 (which may have any of the properties of probe 11 , 50, and/or 111) and a generator 214 (which may have any of the properties of generator 14 and/or 114). As shown in FIG. 4D, a sensing element 220 may be incorporated within control/sensing element 200, along with a control element 230. Alternatively, sensing element 220 may be separate from control element 230 (as shown, for example, in FIGS. 4A-4C). Control element 230 may receive a signal from sensing element 220 and may be configured to compare the signal (e.g., current, voltage, impedance, and/or other values) from sensing element 220 to a reference value 240 (e.g., a desirable energy level for electrode array 12/112). Reference value 240 may include or result in a target energy value 242. Target energy value 242 may be a threshold value provided by a user (via, e.g., a user interface) or provided directly by generator 214 (or another device). Target energy value 242 may be used in determining reference value 240. Control element 230 may be required to convert a received signal or reference value 240 in order to compare the signal to reference value 240 (using, e.g., a comparator). Reference value 240 and/or target energy value 242 may be predetermined values inputted in the sensing element 220, and/or the sensing element 220 may access predetermined values from a processor or controller. In some embodiments, the reference value 240 and/or target energy value 242 may be input by a user. As described above, energy input may correspond to a desired tissue ablation depth, so that a medical professional may treat a selected tissue to only ablate to a target depth. In embodiments, the system 10, 100 may receive feedback of the energy input and automatically apply a reference value 240 and/or target energy value 242.

[0037] Based on the comparison, control element 230 may be operable to engage an electronic switch 250 that controls inflow of energy from generator 214. Switch 250 may be an on/off, binary device that serves only to shut off or permit energy from generator 214 to pass to probe 211 and its electrode array. For example, switch 250 may stop a flow of energy when a comparison with reference value 240 produces a predetermined result (e.g., a target energy value). Control element 230 may serve to automatically shut off energy flow when ablation is determined to be complete. Alternatively, switch 250 may be a more complicated structure that allows an adjustment of energy level that is delivered to probe 211 and its electrode array from generator 214, by, for example, raising or lowering the amount of energy delivered. Switch 250 and/or control element 230 may pulse modulate power from generator 214 to limit an amount of energy measured by sensing element 220 and/or control element 230, using reference value 240.

[0038] FIGS. 5A and 5B show directionally-sensing aspects of the examples described herein. The features described with respect to FIGS. 5A and 5B may be used in conjunction with any of the embodiments of devices and systems described herein. A system 300 may have any of the properties of systems 10 or 100, disclosed herein, and may use any of the components therein. System 300 may also have aspects such as those pictured in FIGS. 4A-4D. [0039] System 300 may include a probe 311 having an electrode array 312 (which may have any of the properties of electrode arrays 12, 54, and/or 112) and a generator 314 (which may have any of the properties of generator 14, 114, and/or 214). System 300 may also include a sensing element 322, which may additionally include a control element, such as those discussed above, with respect to FIGS. 4A- 4D. Sensing element 322 may be integrated with any of the other components of system 300. Sensing element 322 and electrode array 312 may be configured so that sensing element 322 may detect energy levels provided by individual or groups of electrodes of electrode array 312. Such a configuration may facilitate directional sensing by sensing element 322 so that energy levels directed toward tissues along different directions of probe 311.

[0040] For example, as shown in FIG. 5A, electrodes of electrode array 312 may be divided into regions labeled A and B. Region A may face tissue in a first direction radially outward from a central longitudinal axis of probe 311. Region B may face tissue in a second direction outward from a central longitudinal axis of probe 311. The direction that region A faces may be opposite the direction that region B faces or may be otherwise arranged relative to region A. Sensing element 322 may obtain information regarding energy transmittal in region A and region B in order to determine whether energy is being directed as desired (e.g., equally in region A and in region B, or greater in one of region A and region B versus the other of region A and region B). Although two regions are shown, any number of regions may be used, up to the number of electrodes in the electrode array.

[0041] FIG. 5B shows an additional or alternative division of electrodes of electrode array 312. Regions C and D, shown in FIG. 5B may be arranged axially along probe 311. For example, region C may be proximal of region D. Although two regions are shown, any number of regions may be used, up to the number of electrodes in the electrode array. Regions C and D may be used in conjunction with regions A and B, and a given electrode of electrode array 312 may be associated with multiple regions. Sensing element 322 may obtain information regarding energy transmittal in region A and region B in order to determine whether energy is being directed to tissue as desired (e.g., equally in region A and in region B, or greater in one of region A and region B versus the other of region A and region B).

[0042] FIG. 6 shows system 300 used inside a body lumen of a subject. Probe 311 may be positioned in a body lumen and energy may be delivered from generator 314 (either indirectly or directly) to electrode array 312 of probe 311. Display 360 may display measurements of sensing element 322 (not shown in FIG. 6). For example, display 360 may show a graph of power delivered versus time. FIG. 6 shows three measurements, x, y, and z, corresponding to three different regions of electrode array 312. Power measurement x shows a greater amount of power delivered over time than power measurement y. This difference in power measurement may correspond to a difference in depth of ablation. For example, ablated region X may correspond to a region of electrode array 312 measured using power measurement x. Ablated region Y may correspond to a region of electrode array 312 measured using measurement y. Ablation in region X may be deeper than ablation in region Y. If such a difference in ablation is intentional, a user may choose to continue ablating. If such a difference is not intended, a user may manually adjust energy delivered to electrode array 312 (or regions thereof), or a control element (not shown in FIG. 6) may automatically adjust energy levels using a closed-loop system, such as those described above with regard to FIGS. 4A-4D. [0043] FIGS. 7 shows a block diagram of an exemplary sensing element 400 that may be used in conjunction with any of the systems described herein. For example, any of the features of the example shown in FIG. 7 may be included in any of sensing elements 22, 52, 122, 220, and/or 322, described above. Sensing element 400 may include a transducer 402. Transducer 402 may convert power to joules in order to produce an analog signal. An analog signal may be utilized by a control element (not shown in FIG. 7), which may have any of the properties discussed above with regard to FIGS. 4A-4D. Transducer 402 may receive a signal 404 from a generator (not shown) and may transmit power to a probe (not shown) via a signal 406. As discussed above, impedances may be measured (including over time), and such measurements may be received by transducer 402. Transducer 402 may output an analog signal 408 representing energy, which may be measured in Joules. The signal may be transmitted to components that perform signal processing (which may be components of sensing element 400 or external to sensing element 400) and/or to feedback control elements, such as those described with regard to FIGS. 4A-4D.

[0044] While principles of the present disclosure are described herein with reference to illustrative examples for particular applications, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, and substitution of equivalents all fall within the scope of the examples described herein. Accordingly, the invention is not to be considered as limited by the foregoing description.

Claims

CLAIMS We claim:

1. A device for sensing an electrical parameter, the device comprising: a sensing element configured to be in electrical series between a generator and an ablation probe; wherein the sensing element is configured to measure at least one of a current or a voltage being delivered from the generator to the ablation probe.

2. The device of claim 2, wherein the sensing element is configured to be removably connected to the generator and the ablation probe.

3. The device of any one of the preceding claims, wherein an output of the sensing element is an analog energy signal.

4. The device of claim any one of the preceding claims, wherein the generator is an RF generator, and the sensing element is contained within the ablation probe.

5. The device of claim any one of the preceding claims, further including a control element configured to adjust a flow of energy from the generator to the ablation probe.

6. The device of claim 5, wherein the control element is configured to adjust the flow of energy to the ablation probe using a signal output by the sensing element.

7. The device of claim 6, wherein the control element is configured to compare the signal output to a reference value.

8. The device of claim 7, wherein the control element is configured to stop the flow of energy when the comparison of the signal output to the reference value satisfies a predetermined condition.

9. The device of any one of the preceding claims, further including a processor configured to provide information on a display regarding a depth of tissue ablation, an amount of energy delivered, or an amount of powered delivered.

10. The device of any one of the preceding claims, wherein the sensing element is configured to measure the at least one of the current or the voltage being delivered to a first region of the ablation probe and to measure the at least one of the current or the voltage through a second region of the ablation probe.

11. The device of any one of the preceding claims, further including a processor configured to provide information on a display regarding a first energy level delivered to the first region of the ablation probe and a second energy level delivered to the second region of the ablation probe.

12. The device of claim 11 , wherein the processor is configured to use the first energy level to determine a first depth of tissue ablation in a first tissue region and the second energy level to determine a second depth of tissue ablation in a second tissue region.

13. The device of any one of the preceding claims, wherein the generator is a radiofrequency generator, and wherein the ablation probe includes at least one bipolar electrode.

14. The device of any one of the preceding claims, wherein the sensing element includes a transducer.

15. The device of any one of the preceding claims, further including a processor configured to use the at least one of the current or the voltage to determine an energy level delivered to the ablation probe and to use the energy level to determine a depth of tissue ablation.