DE202014102548U1 - Systems for radiometrically measuring a temperature and detecting tissue contact before and during a tissue ablation - Google Patents

Abstract

A system for facilitating the detection of contact with a target tissue of an individual comprising: a catheter comprising a radio frequency electrode and a radiometer; and a processor configured to receive a signal from the radiometer and provide an output indicative of contact between the radio frequency electrode and the target tissue of the individual based at least in part on tissue properties determined from the signal received from the radiometer will.

Description

Field of the invention

This application generally relates to systems for measuring temperature and detecting tissue contact prior to and during tissue ablation.

Background of the invention

Tissue ablation can be used to treat a variety of clinical disorders. For example, tissue ablation can be used to treat cardiac arrhythmias by destroying abnormal pathways that would otherwise conduct abnormal electrical signals to the heart muscle. Several ablation techniques have been developed, including cryoablation, microwave ablation, radio frequency (RF) ablation and radiofrequency ultrasound ablation. For cardiac applications, such techniques are usually performed by a physician inserting a catheter with an ablation tip over the venous system into the endocardium, positioning the ablation tip adjacent to it, which the physician uses based on tactile feedback to correlate electrocardiogram (ECG) signals, the anatomy and / or fluorescent imaging assumes that it is an appropriate area of the endocardium, the flow of a flushing agent operated to cool the surface of the selected area, and then the Ablationsspitze for a period of time and with a power that is believed to be sufficient to destroy tissue in the selected area.

Commercially available ablation tips may include thermocouples to provide temperature feedback via a digital display, such thermocouples typically failing to provide significant temperature feedback during rinsed ablation. For example, the thermocouple measures only the surface temperature, but the heating or cooling of the tissue resulting in tissue ablation may occur at depths below the tissue surface. In addition, in operations where the surface of the fabric is cooled with a rinse, the thermocouple measures the temperature of the rinse, thereby further obscuring any useful information about the temperature of the fabric, particularly at depth. As such, the physician has no useful feedback on the temperature of the tissue as it is being ablated or whether the period of ablation is sufficient.

In addition, during an ablation procedure, it is important for the physician to position the ablation tip directly on the heart surface (eg, making good contact) before activating the ablation energy source and attempting to ablate the tissue. If the doctor does not have good tissue contact, the ablation energy may heat the blood instead of the tissue, resulting in the formation of edema, e.g. As a fluid-filled bag or bladder, on the tissue surface. Such edema may inhibit the adequate destruction of abnormal nerve pathways in the tissue. For example, edema may physically obstruct the physician's ability to contact a desired area of tissue with the ablation tip, thereby hindering the destruction of a desired nerve pathway. In addition, partial lesions or lesions at undesired sites were found after the physician completed the procedure and the edema dissolved. The formation of such partial or unwanted lesions is believed to be caused by reduced contact between the ablation tip and the tissue, resulting in tissue temperature insufficient to cause tissue necrosis. Edema and partially formed lesions can also make it more difficult to form an effective lesion in the future, e.g. During a repair ablation within the same procedure or later during a secondary procedure.

Accordingly, it may only be apparent after completion of the process that the targeted abnormal pathway has not been adequately interrupted - e.g. If the patient continues to have cardiac arrhythmias. In such circumstances, the physician may not know if the procedure failed because the wrong tissue area was ablated because the ablation tip was not actuated long enough to destroy the abnormal pathway because the ablation tip did not or insufficiently touch the tissue. because the performance of the ablation energy was not sufficient or a combination of the above. Upon repetition of the ablation procedure to attempt re-treatment of the arrhythmia, the physician may have as little feedback as during the first procedure and may fail again with respect to the destruction of the abnormal pathway. In addition, there may be a certain risk that the doctor will again treat a previously ablated area of the endocardium and not ablate the guide pathway, but will damage adjacent tissues.

In order to avoid repetition of the ablation procedure per se, under some circumstances the physician may ablate a number of areas of the endocardium along which the abnormal pathway The assumption is that it will improve the likelihood of line break along this pathway. Again, the feedback that the doctor should use to determine if any of these ablated areas are sufficiently destroyed is again insufficient.

The U.S. Patent No. 4,190,053 von Sterzer describes a hyperthermia treatment device that uses a microwave source to introduce energy into the living tissue to cause hyperthermia. The apparatus includes a radiometer for measuring a temperature in depth within the tissue and a controller that returns a control signal from the radiometer corresponding to the measured temperature to control the application of energy from the microwave source. The device alternates between supplying microwave energy from the microwave source and measuring the radiant energy with the radiometer to measure the temperature. As a result of this time division multiplexing of the energy application and temperature measurement, temperature values reported by the radiometer are not measured simultaneously with the energy input.

The U.S. Patent No. 7,769,469 by Carr et al. describes an integrated heating and sensing catheter device for treating arrhythmias, tumors, and the like, with a diplexer that allows almost simultaneous heating and temperature measurement. This patent also describes that the temperature measured by the radiometer can be used to control the application of energy so that e.g. B. is held a selected heating profile.

Although the application of radiometry promises precise temperature sensing and control, so far there are few successful commercial medical applications of this technology. A disadvantage of previously known systems is that due to slight deviations in the design of the microwave antenna used in the radiometer, which can lead to significant differences in the measured temperature from catheter to catheter, it is not possible to achieve results with high reproducibility. Problems also exist with respect to aligning the radiometer antenna with the catheter to adequately detect radiant energy emitted by the tissue and with respect to shielding radio frequency microwave components in the surgical environment to prevent interference between the radiometer components and other units in the surgical field.

The acceptance of microwave-based hyperthermia treatments and temperature measuring techniques is further hampered by the investment costs associated with the implementation of radiometric temperature control schemes. Radiofrequency ablation techniques have found a significant following in the medical community, although such systems are associated with severe limitations, e.g. B. that it is not possible to accurately measure the tissue temperature in depth, in the z. B. a rinse is used. However, the widespread acceptance of RF ablation systems, a comprehensive knowledge base of the medical community regarding such systems, and the significant costs associated with switching to newer technologies and related training have drastically delayed the general acceptance of radiometry.

In view of the foregoing, it would be desirable to provide apparatus and methods that permit radiometric measurement of tissue depth in tissue and allow the use of such results to control the application of ablation energy in an ablation treatment, e.g. In a hyperthermia or hypothermia treatment, in particular, a contact between the ablation tip and the tissue can be easily assessed.

It would also be desirable to provide apparatus and methods that use microwave radiometer components that are easy to manufacture and calibrate to provide a measurement with high reproducibility and reliability.

In addition, it would be desirable to provide apparatus and methods that enable a radiometric temperature measurement and control technique to be integrated in a manner readily accessible to physicians trained in the use of previously known RF ablation catheters with minimal retraining, and US Pat provide the physicians with easily understandable signals as to whether the ablation tip is in contact with tissue.

It would also be desirable to provide apparatus and methods that enable radiometric temperature measurement and control techniques to be readily utilized with previously known electrosurgical RF generators, thereby reducing the capital costs required to implement such new techniques.

Summary of the invention

In view of the above, it would be desirable to provide apparatus and methods for treating living tissue using a radiometer for temperature measurement and control. According to one aspect of the invention, there are provided systems for radiometrically measuring temperature and detecting tissue contact prior to and during RF ablation, i. H. for calculating a temperature and detecting tissue contact based on one or more signals from a radiometer. Unlike standard thermocouple techniques used in existing commercial ablation systems, a radiometer can provide useful information about a tissue temperature at depth - where the tissue is ablated - and thus provide feedback to the physician about the extent of tissue damage while selecting a selected area of the tissue Tissue ablated. In addition, the radiometer can provide useful information on whether an ablation tip is in contact with tissue and thus provide feedback to allow the physician to properly contact and ablate the tissue.

In one embodiment, the present invention includes an interface module (system) adapted to a previously known commercially available ablation energy generator, e.g. As an electrosurgical generator, can be connected, thereby enabling a use of radiometric techniques at a reduced cost. In this way, the conventional electrosurgical generator can be used to deliver ablation energy to an "integrated catheter tip" (ICS) comprising an ablation tip, a thermocouple, and a radiometer for detecting the volumetric temperature of a tissue being ablated. The interface module is configured to connect between the conventional electrosurgical generator and the ICS and coordinate signals therebetween. The interface module thus provides the electrosurgical generator with the information needed for operation, transfers ablation energy to the ICS under the physician's control, displays the temperature in the depth of a tissue via a temperature display as it is being ablated, and provides a visual or audible indication for tissue contact for use by the doctor. The displayed temperature and tissue contact detection may be calculated based on one or more signals measured by the radiometer using algorithms as discussed below.

In an exemplary embodiment, the interface module includes a first input / output (I / O) port configured to receive a digital radiometer signal and a digital thermocouple signal from the ICS, and a second I / O port. configured to receive ablation energy from the electrosurgical generator. The interface module also includes a processor, a patient relay in communication with the processor and the first and second I / O ports, and a persistent computer-readable medium. The computer-readable medium stores operating parameters for the radiometer and thermocouple and instructions for the processor to use in coordinating the operation of the ICS and the electrosurgical generator.

The computer readable medium preferably stores instructions that cause the processor to perform the step of computing a temperature adjacent to the ICS based on the digital radiometer signal, the digital thermocouple signal, and the operating parameters. This temperature is expected to provide significantly more accurate information about lesion quality and temperature at depth in the tissue than a temperature based solely on a thermocouple measurement. The computer-readable medium may also store instructions to cause the processor to cause the temperature indicator to display the calculated temperature so that the physician may, for example, check the temperature reading. B. can control the period of ablation in response to the displayed temperature. The computer readable medium may also store instructions to cause the processor to close the patient relay so that the patient relay receives ablation energy received at the second I / O port from the electrosurgical generator to the first I / O port ICS forwarded. Note that the instructions may cause the processor to keep the patient relay in a normally closed state and to open the patient relay upon detection of unsafe conditions.

The computer readable medium preferably further stores instructions that cause the processor to perform the step of determining whether the ICS is in contact with tissue based on the digital radiometer signal. Because z. For example, if blood and tissue have different dielectric constants, the digital radiometer signal may change as the ICS is brought into contact with or loosened contact with the tissue. The instructions may cause the processor to monitor the digital radiometer signal for changes. All such changes can be made in advance defined limit value (also stored on the computer readable medium). If it is determined that the change is greater than the threshold, the processor outputs a signal to an output device that indicates whether the ICS is in contact with tissue in response to the signal. The output unit can, for. B. be a visual display unit that represents the tissue contact visually, z. For example, a light that illuminates when tissue contact is present, or an audio unit that acoustically represents tissue contact, e.g. For example, a speaker that generates a sound when tissue contact is present. Preferably, the processor determines if the ICS is in contact with the tissue before relaying ablation energy to the ICS.

Brief description of the drawings

1A Fig. 3 is a schematic representation of a first embodiment of an assembly including an interface module with a tissue contact indicator in accordance with one aspect of the present invention including an indication of the front and back panels of the interface module and exemplary connections therebetween, a previously known ablation energy generator, e.g. As an electrosurgical generator, and an integrated catheter tip (ICS) contains.

1B is a schematic representation of the exemplary connections to and from the interface module of 1A and shows connections among other components that can be used with the interface module.

2A is a schematic representation of the internal components of the interface module of the 1A to 1B shows.

2 B shows further internal components of the interface module of 2A as well as selected connections to and from the interface module schematically.

3A shows steps in a method for using the interface module of 1A to 2 B during a tissue ablation.

3B shows steps in a method for calculating a radiometric temperature using digital signals from a radiometer and a thermocouple and operating parameters.

3C shows steps in a method for controlling an ablation process using a temperature based on one or more signals from a radiometer using the interface module of the 1A to 2 B was calculated.

4A FIG. 12 shows data obtained during an exemplary tissue-contact measurement process using the interface module of FIG 1A to 2 B was carried out.

The 4B to 4E show data obtained during exemplary ablation procedures using the interface module of FIG 1A to 2 B were carried out.

5A FIG. 12 shows a top view of an exemplary patient interface module (PSM) connected to an integrated catheter tip (ICS) for use with the interface module of FIG 1A to 2 B ,

5B schematically shows selected internal components of the PSM of 5A according to some embodiments of the present invention.

The 6A to 6B 11 show an exploded perspective view of an exemplary integrated catheter tip (ICS) for use with the interface module of FIG 1A to 2 B and the PSM the 5A to 5B according to some embodiments of the present invention.

Detailed description

Embodiments of the present invention provide systems and methods for radiometrically measuring temperature and detecting tissue contact prior to and during ablation, particularly cardiac ablation. As noted above, commercially available cardiac ablation systems may include thermocouples for measuring temperature, but such thermocouples may not provide the physician with adequate tissue temperature or tissue contact information. Thus, the must Physicians may need to make a "well-founded estimate" of whether an ablation tip is in contact with tissue and whether a particular area of tissue has been adequately ablated to achieve the desired effect. By comparison, calculating a temperature based on one or more signals from a radiometer is expected to provide a physician with accurate information about the temperature of a tissue at depth, even during a purged process. In addition, the one or more signals from the radiometer may be used to determine if the ablation tip is in sufficient contact with the tissue before attempting to ablate the tissue to increase the likelihood of edema formation as described above reduce the likelihood of the formation of effective transmural lesions. The present invention provides a "retrofit solution" that includes an interface module that utilizes existing, commercially available ablation energy generators such as electrosurgical generators. In accordance with one aspect of the present invention, the interface module displays a tissue temperature and provides an indication of tissue contact based on one or more signals measured by a radiometer, which a physician may use to perform ablation procedures with significantly greater accuracy than when using only a thermocouple for a temperature measurement can be achieved.

First, a comprehensive overview of the interface module is provided, including the tissue contact indicator and connections to it. Thereafter, further details about the internal components of the interface module and exemplary methods for calculating a radiometric temperature, determining tissue contact and controlling an ablation process based thereon are provided. Data obtained during experimental procedures are also shown. Finally, more details about components that can be used with the interface module are provided.

1A shows plan views of a front panel 111 , a back plate 112 and connections to and from an exemplary interface module 110 constructed in accordance with the principles of the present invention. As in 1A shown, the front panel can 111 of the interface module 110 with a catheter 120 connected to a patient interface module (PSM) 121 and an integrated catheter tip (ICS) 122 contains. The catheter 120 is optionally steerable or may be non-steerable and is used in conjunction with a robotic positioning system or third-party steerable sheath (not shown). The ICS 122 is performed by a physician (optionally under the above-noted mechanical help) during a procedure in an individual 101 positioned on a grounded table 102 lies. The ICS 122 may include, inter alia, an ablation tip, a thermocouple, and a radiometer for sensing the volumetric temperature of a tissue undergoing ablation. The ICS 122 optionally includes one or more purge ports, which in one embodiment may be directly connected to a commercially available purge pump.

In embodiments in which the ablation energy is radio frequency (RF) energy, the ablation tip may include a rinsed ablation electrode, such as an ablation electrode. B. with reference to the 6A to 6B described in more detail. The ICS 122 In addition, one or more electrocardiogram (ECG) electrodes may be used for monitoring the electrical activity of the individual's heart 101 contain. The interface module 110 receives signals from the thermocouple, radiometer and optional ECG electrodes of the ICS 122 about the PSM 121 , The interface module 110 Provides power to operate the PSM and sensors (thermocouple, radiometer, and ECG electrodes) through the PSM 121 to the ICS 122 and Ablation Energy ready it through the ablation tip to the individual 101 apply applies.

The front panel 111 contains a tissue contact indicator 170 , which is an output device configured to indicate if the ICS 122 is in contact with tissue, which z. B. the interface module 110 based on one or more signals from the radiometer, as described in more detail below. The tissue contact indicator 170 may include a visual display unit that detects the interface module 110 whether the ICS 122 in contact with tissue, visually indicating. For example, the tissue contact indicator 170 Contain a light that lights up when the interface module 110 determines that the ICS 122 is in contact with a tissue and is dark when the interface module 110 determines that the ICS 122 not in contact with tissue. Alternatively, the tissue contact indicator 170 an audio unit containing the determination of the interface module 110 whether the ICS 122 In contact with tissue, acoustically. For example, the tissue contact indicator 170 include a speaker that produces a sound when the interface module 110 determines that the ICS 122 is in contact with a tissue, and is silent when the interface module 110 determines that the ICS 122 not in contact with tissue. The tissue contact indicator 170 can continuously produce a sound throughout the duration of the contact and stop generating the sound when the contact is lost so that the doctor can more easily determine if the tissue contact has been lost. Alternatively, the tissue contact indicator 170 when making a contact, generate a short tone at a first frequency and a second tone at a second frequency when the contact is lost. Optionally contains the tissue contact indicator 170 a visual display unit and an audio unit to provide the physician with both a visual and audible indication of tissue contact.

The back plate 112 of the interface module 110 can via a connection cable 135 with a commercially available, previously known ablation energy generator 130 be connected, z. B. an electrosurgical generator 130 like a Stockert EP shuttle 100 Generator (Stockert GmbH, Freiburg Germany) or a Stockert-70 RF generator (Biosense Webster, Diamond Bar, California). In embodiments where the electrosurgical generator 130 a Stockert EP Shuttle Generator or Stockert 70 RF Generator contains the generator 130 a display unit 131 to display a temperature and the impedance and time associated with the application of an RF ablation energy dose; a power control button 132 To give a doctor the manual setting of the individual 101 to enable RF ablation energy to be supplied; and a start / stop / mode input 133 to allow a physician to initiate or stop the delivery of RF ablation energy. The start / stop / mode input 133 In addition, it may be configured to control the mode of power delivery, e.g. B. whether the energy is to be switched off after a certain period of time.

Even if the generator 130 configured to have a temperature on the display unit 131 indicates that temperature is based on measurements from a standard thermocouple. However, as noted above, this reported temperature may be inaccurate while flushing agent and ablation energy are applied to the tissue. The interface module 110 puts the generator 130 over the connection cable 135 a thermocouple signal for use in displaying such temperature and signals from the ECG electrodes ready; and puts on an indifferent electrode cable 134 a continuous connection to an indifferent electrode 140 ready. The interface module 110 receives via the connection cable 135 from the generator 130 RF ablation energy, which is the module 110 controllable to the ICS 122 for use in the ablation of tissue of the individual 101 provides.

As will be known to those skilled in the art, a clinician for a single-ended RF ablation procedure may use an indifferent electrode (IE). 140 on the back of the individual 101 position so as to provide a voltage differential that allows for transmission of RF energy into the tissue of the subject. As in the embodiment shown, the IE 140 over a first cable 141 for indifferent electrodes with the interface module 110 connected. The interface module 110 routes the IE signal to a second cable 134 for indifferent electrodes, with an input opening for indifferent electrodes on the electrosurgical generator 130 connected is. Alternatively, the IE 140 via a corresponding wiring (not shown) directly to this connection of the electrosurgical generator 130 be connected.

It should be understood that electrosurgical generators other than the Stockert EP shuttle generator or the Stockert 70 RF generator may be suitably used, e.g. As other makes or models of electrosurgical HF generators. Alternatively, generators may be used which produce other types of ablation energy, e.g. As microwave generators, cryosurgical sources or high-frequency ultrasonic generators. The ablation energy generator 130 does not necessarily have to be commercially available, although use of such as noted above may be convenient. It should also be understood that the connections described herein are on any surface or plate of the interface module 110 and that the functionalities of different connectors and input / output (I / O) ports may be combined or otherwise altered as appropriate.

The front panel 111 of the interface module 110 contains a temperature display 113 , z. A digital 2 or 3 digit display unit configured to display a temperature that is from an interface module 110 internal processor was calculated, such. B. with reference to the 2A to 2 B and 3A described in more detail. Other types of temperature displays, such as multi-color liquid crystal displays (LCDs), may alternatively be used. In one embodiment, the functionalities of the temperature display 113 and the tissue contact indicator 170 provided by a single display unit configured to both display a temperature and provide an indication of whether the interface module 110 has determined that the ICS 122 in contact with tissue. For example, the background of the temperature display 113 be configured to change from one color to another (for example, from red to blue) when the interface module 110 determines that the ICS 122 in contact with tissue. In such an embodiment may also be separate audible tissue contact indicator 170 optionally provided as described above. The front panel 111 also includes connectors (not marked) through which the interface module 110 with the ICS 122 about the PSM 121 and with the IE 140 over the cable 141 for indifferent electrodes is connected.

The back plate 112 of the interface module 110 Contains connectors (not marked) through which the interface module 110 over the cable 134 for indifferent electrodes and the connection cable 135 with the electrosurgical generator 130 connected is. The back plate 112 of the interface module 110 also contains data ports 114 which are configured to output one or more signals to a suitably programmed personal computer or other remote unit, e.g. An EP monitoring / recording system such as the LABSYSTEM. ^TM PRO EP Recording System (CR Bard, Inc., Lowell, Mass.). Such signals can z. B. Signals generated by the thermocouple, the radiometer, and / or the ECG / electrodes of the ICS coming from the interface module 110 calculated tissue temperature and the same include.

It will be up now 1B Reference is made in the exemplary connections to and from the interface module 110 from 1A and compounds are described among other components. In 1B is an interface module 110 with a catheter 120 functionally connected to a patient interface module (PSM) 121 and an integrated catheter tip (ICS) 122 comprising a radiometer, an ablation tip, a thermocouple (TE) and optionally also ECG electrodes and / or one or more irrigations. The interface module 110 is also functional with an electrosurgical generator 130 and an indifferent electrode 140 connected.

The electrosurgical generator 130 is via an appropriate wiring 161 or alternatively via data connections 114 of the interface module 110 and corresponding cabling (not shown) functionally optional with an electrophysiology (EP) monitoring / recording system 160 connected. The EP monitoring / recording system 160 can z. As various monitors, processors and the like, the relevant information about an ablation process for a doctor show, z. The heart rate and blood pressure of the individual, the temperature recorded by the thermocouple at the catheter tip, the ablation power and the time over which it is applied, fluoroscopic images, and the like. EP surveillance / recording systems are commercially available, e.g. Eg the MEDELEC. ^TM Synergy T-EP-EMG / EP Monitoring System (CareFusion, San Diego, Calif.) Or the LABSYSTEM. ^TM PRO EP Recording System (CR Bard, Inc., Lowell, Mass.).

If the ICS 122 includes one or more flushing connections, a practical means for providing flushing means to such connections is a flushing pump 140 connected to the electrosurgical generator 130 is connected, wherein the pump is operatively connected to the generator and in fluid communication with the ICS 122 stands, via a connector 151 , For example, the Stockert 70 RF generator is for use with a CoolFlow. ^TM Irrigation Pump, also manufactured by Biosense Webster. In particular, the Stockert 70 HF generator and the CoolFlow. ^TM pump via a commercially available interface cable to work as an integrated system that operates in much the same way as it would with a commercially available standard catheter tip. For example, the doctor instructs before positioning the ICS 122 in the body, the pump provides a slow flow rate of flushing fluid to the ICS, as it would do to a standard catheter tip; then the ICS is positioned in the body. When the doctor of the "Start" button on the side of the generator 130 presses, the generator can pump 150 to provide a high flow rate of lotion for a pre-determined period of time (eg, 5 seconds) before providing RF ablation energy, again as it would for a standard catheter tip. Upon completion of the RF ablation energy application, the pump returns 150 then return to a slow flow rate until the doctor releases the ICS 122 removed from the body and the pump shuts off manually.

It will now be on the 2A to 2 B Reference is made to further details on internal components of the interface module 110 of the 1A to 1B are provided.

2A shows internal components of one embodiment of the interface module 110 schematically. The interface module 110 contains first, second, third and fourth ports 201 - 204 through which it communicates with external components. In particular, a first connection 201 an input / output (I / O) connector configured to have a PSM 121 with a catheter 120 is connected as in 1A shown. The connection 201 Receives digital radiometer and digital thermocouple (TE) signals and optionally from the ICS 122 generated ECG signals as input from the catheter 120 and provides RF ablation energy as well as power for the circuit within the ICS 122 and the PSM 121 as an issue to the catheter 120 ready. The second connection 202 is also an I / O connector that is configured to connect via a connection cable 135 with an electrosurgical generator 130 is connected as in 1A shown, and RF ablation energy as input from the generator 130 receives and a reconstituted analog thermocouple (TE) signal and one or more ECG raw signals as output to the generator 130 provides. The third connection 203 is an input connector that is configured to be over a cable 134 for indifferent electrodes with an indifferent electrode (IE) 140 is connected as in 1A shown, and the fourth connection 204 is an output port that is configured to be over a cable 141 for indifferent electrodes with the generator 130 is connected as in 1A shown. As in 2A shown, the interface module acts 110 as a pass for the IE signal from the IE 140 to the generator 130 and simply receives an IE signal at the third port 203 and puts the IE signal to the generator 130 at the fourth connection 204 ready.

The interface module 110 also includes a processor 210 Using a non-volatile (persistent) computer-readable storage 230 , a user interface 280 , a load relay 260 and a patient relay 250 connected is. The memory 230 stores a programming that the processor 210 causes, in relation to the below 3A to 3C perform the described steps, thereby increasing the functionality of the interface module 110 is controlled. The memory 230 also stores parameters supplied by the processor 210 be used. For example, the memory 230 a set of operating parameters 231 for the thermocouple and the radiometer and a temperature calculation module 233 store, which is the processor 210 used to calculate the radiometric temperature based on the digital TE and radiometer signals at the first I / O port 201 received as described below with respect to 3B described in more detail. The operating parameters 231 can be obtained by calibration or fixed parameters. The memory 230 stores a set of security parameters about it 232 the processor 210 used to maintain safety conditions during an ablation procedure, as described below 3C described in more detail. The memory 230 also stores a decision module 234 that the processor 210 used to open and close the patient relay 250 and the load relay 260 On the basis of his investigations of the temperature and safety conditions to control, as described below with reference to the 3A to 3C described in more detail. When closed, the patient relay conducts 250 Ablation energy from the second I / O port 202 to the first I / O port 201 , When closed, the load relay conducts 260 Ablation energy across a dummy load D (resistor with a resistance of, for example, 120 ohms) and the fourth I / O port 204 to the IE 140 back. The memory 230 also stores a pre-determined threshold 235 and a tissue contact module 236 that the processor 210 used to determine if the ICS 122 is in contact with tissue and to provide an output to the physician indicative of such contact, as described below with respect to U.S. Pat 3A described in more detail.

As in 2A shown contains the interface module 110 In addition, a user interface 280 , via which a user information about the temperature adjacent to the ICS 122 that from the processor 210 calculated as well as other potentially useful information. In the embodiment shown, the user interface includes 280 a digital temperature display 113 showing the instantaneous temperature coming from the processor 210 was calculated. In other embodiments (not shown), the display 113 an LCD unit that not only displays the instantaneous temperature of the processor 210 but also graphically displays changes in temperature over time for use by the physician during the ablation process. The user interface 280 may also have data ports 114 which may be connected to a computer or EP surveillance / recording system via appropriate wiring as outlined above and which may output digital or analog signals received from the interface module 110 be received or generated, for. B. one or more radiometer signals, a thermocouple signal and / or the processor 210 calculated temperature. Preferably, the user interface contains 280 also a tissue contact indicator 170 that is configured to handle the investigations of the processor 210 whether the ICS 122 in contact with tissue based on the predetermined threshold 235 and in the store 230 stored tissue contact module 236 indicating as below with reference to 3A described in more detail.

To a potential degradation of the performance of the processor 210 , the memory 230 or the user interface 280 To inhibit, resulting from electrical contact with RF energy, the interface module 110 an optoelectronics 299 contain the information to the processor 210 and from this communicates the transmission of RF energy to the processor 210 , the memory 230 or the user interface 280 but essentially inhibits. This isolation is indicated by the dashed line in 2A shown. For example, the optoelectronics 299 include a circuit that works with the first E / O port 201 is connected to the digital TE and radiometer signals from the first I / O port 201 and converts such digital signals into optical digital signals. The optoelectronics 299 In addition, it may include an optical transmitter operatively connected to such a circuit, and these optical digital signals over clearance to the processor 210 transfers. The optoelectronics 299 In addition, an optical receiver that works with the processor 210 is connected and receives such optical digital signals, and a circuit containing the optical digital signals into digital signals for use by the processor 210 transforms. The opto-electronic circuit in communication with the processor may also be operatively connected to a second optical transmitter and may receive signals from the processor 210 which are to be transmitted via free space to an optical receiver which communicates with the circuit and receives and processes the digital TE and radiometer signals. For example, the processor 210 transmit a signal to such a circuit via an optical signal, causing the circuit to generate an analog version of the TE signal and provide that analog signal to the second I / O port. Since optoelectronic circuits, transmitters and receivers are known in the art, their specific components are in 2A Not shown.

With reference to 2 B are further internal components of the interface module 110 of the 2A as well as selected connections to and from the interface module. 2 B FIG. 10 is an exemplary schematic diagram of a ground and power scheme suitable for use with the interface module. FIG 110 with an electrosurgical HF generator, z. A Stockert EP Shuttle or Stockert 70 RF generator. Other grounding and powering schemes may suitably be used with other types, makes, and models of electrosurgical generators, as will be understood by those skilled in the art.

As in 2 B shown contains the interface module 110 an isolated main energy supply 205 , which can be connected to a standard 3-pin A / C socket 1 grounded to the mains ground G. The interface module 110 also contains several internal groundings labeled A, B, C and I. The internal ground A is across a relatively low capacitance capacitor (eg, a 10 pF capacitor) and a relatively high resistance resistor (eg, a 20-NE / resistor), which substantially prevents that the internal ground A is potential-free, connected to the external power ground G. The internal ground B is across a low resistance path (eg, a track or one or more resistors providing a resistance of less than 1000Ω, eg, a resistance of about 0Ω) to the internal ground A connected. Likewise, the internal ground C is connected to the internal ground B via another low resistance track. The internal ground I is an isolated ground via a relatively low capacitance capacitor (eg, a 10 pF capacitor) and a relatively high resistance resistor (eg, a 20 MΩ resistor) essentially prevents the isolated ground I is potential-free, with the internal ground C connected.

The isolated main power supply 205 is connected to the internal ground A via a low resistance track. The isolated main power supply 205 is also connected to one or more internal isolated power supplies and provides power (eg, ± 12V) thereto, which in turn powers power relative to the interface module 110 provides internal components. Such components include components incorporated in 2A are shown, but not limited thereto. For example, the interface module 110 one or more isolated power supplies 220 included, the power (for example, ± 4 V) to the processor 210 , the memory 230 and the analog circuit 240 provide. The analog circuit 240 can be components of the user interface 280 including a temperature gauge 113 and a circuit that signals for output to data terminals 114 prepared accordingly. The data connections 114 as well as the analog circuit 240 are connected via low resistance tracks to the internal ground B, while the processor and memory 210 . 230 connected via low resistance tracks to ground C The interface module may also include one or more isolated power supplies 270 contain the power (eg ± 4 V) to the IKS 122 , the PSM 121 and the RF circuit 290 provide.

The RF circuit 290 can patient and load relay 250 . 260 and a circuit that receives the radiometer and thermocouple signals and provides such signals to the processor via an optoelectronic connection, and circuitry that generates a clock signal to be provided to the ICS, as described below with reference to FIGS 5B described in more detail. The RF circuit 290 , the IKS 122 and the PSM 121 are connected to the isolated internal ground I via low resistance tracks.

As in 2 B shown is the energy supply 139 of the electrosurgical HF generator 130 that in terms of the generator 130 can be arranged externally, as in 2 B shown or in relation to the generator 130 can be internally connected to a standard two or three pole A / C socket 2. The generator power supply 139 However, it is not connected to the ground of the socket and thus not to the mains ground G, as is the isolated main power supply.

Instead, the generator energy supply 139 and the electrosurgical HF generator 130 over low resistance tracks between the generator 130 and the PMS 121 and the ICS 122 and over low resistance tracks between the PMS 121 and the ICS 122 and the internal isolated ground I to the internal isolated ground I of the interface module 110 connected. Therefore, the RF circuit 290 , the PSM 121 that IE 140 and the generator 130 all grounded with an internal grounded I that is essentially the same potential as the IKS 122 having. When RF energy from the generator 130 via the interface module 110 to the ICS 122 is applied, is the grounding of the RF circuit 290 , the PMS 121 , the IKS 122 , the IE 140 and the generator with the RF energy amplitude, which may be a sine wave of 50 to 100 V at 500 kHz, substantially floating.

As in 2 B further demonstrated, the power of ± 12V, which is the main isolated power supply 205 to the isolated processor / memory / analog power supply 220 and to the isolated ICS / RF power supply 270 may be connected to an A / C socket 1 via a parasitic capacitance (PK, approximately 13 pF), as may the ± 4V power supplied by such power supplies to their respective components. Such a parasitic compound is known to the person skilled in the art. Note that the specific resistances, capacities and voltages referred to by reference 2 B are merely exemplary and can be varied according to different configurations.

It will be up now 3A Reference is made to a method 300 to use the interface module 110 of the 1A to 2 B during a tissue ablation process. The doctor connects the integrated catheter tip (ICS) 122 and an indifferent electrode (IE) 140 with the respective I / O ports of the interface module 110 (Step 301 ). Such as In 1A shown, the ICS 122 via a patient interface module (PMS) 121 with a first connector on a front panel 111 of the interface module 110 be connected, and the IE 140 can via a cable 141 for indifferent electrodes with a third connector on the front panel 111 be connected. The first connector is operationally connected to a first I / O port 201 connected (see 2A ), and the third connector is functionally connected to a third I / O port 203 connected (see 2A ).

In the process 300 from 3A The doctor may use an electrosurgical generator 130 with one or more I / O ports of the interface module 110 connect (step 302 ). Such as In 1A shown, the electrosurgical generator 130 via a connection cable 135 with a second connector on the back plate 112 of the interface module 110 can be connected and also via a cable 134 for indifferent electrodes with a fourth connector on the back plate 112 be connected. The second connector is operatively connected to a second I / O port 202 connected (see 2A ), and the fourth connector is operatively connected to a fourth I / O port 204 connected (see 2A ).

In the process 300 from 3A When the doctor initiates a flushing agent flow, positions the ICS 122 within the individual, e.g. In the heart of the individual, and positions the IE 140 in contact with the individual, e.g. B. on the back of the individual (step 303 ). The person skilled in the art, the methods for the corresponding positioning of catheter tips with respect to the heart of an individual in the context of an ablation process known, for. Via the peripheral arterial or venous system.

In the process 300 from 3A receives the interface module 110 digital radiometer, digital thermocouple and / or analog ECG signals from the ICS and receives ablation energy from the generator 130 (Step 304 ), z. B. using the connections, connections and tracks, with respect to the 1A to 2 B are described. Preferably, the generator 130 such ablation energy via inputs 133 at the front of the generator 130 to the interface module in response to the doctor pressing "Start" (see 1A ).

In the process 300 from 3A calculates the interface module 110 the temperature adjacent to the ICS 122 based on the radiometer and thermocouple signals and displays them (step 305 ). This calculation can z. From a processor 210 based on instructions in a temperature calculation module 233 be carried out in a store 230 is stored (see 2A ). Exemplary methods of performing such a calculation are described below with reference to FIG 3B described in more detail.

In the process 300 from 3A determines the interface module 110 on the basis of the digital radiometer signal, whether the IKS 122 in contact with tissue (step 306 ). For example, a tissue contact module 236 that in the store 230 is stored, the processor 210 of the interface module 110 to first identify a change in the radiometer signal. In particular, the magnitude of the radiometer signal is inter alia a function of the temperature of the one or more materials near the radiometer and the dielectric constants of the one or more materials. Blood and tissues have dielectric constants that are different from each other. If the doctor uses the ICS 122 Therefore, the radiometer signal will vary accordingly as it contacts or loosens contact with, ie, contacts, or contacts the contact with a material having a different dielectric constant than the blood. When the tissue and blood are at the same temperature, changes in the radiometer signal of the ICS may occur 122 attributed to contact with the tissue or loses contact with the tissue. Such changes may be viewed as a change in the magnitude (eg, voltage) of the radiometer signal from a baseline or as a percentage change in the radiometer signal from a baseline, where the baseline is the magnitude of the signal when the ICS 122 in the blood and away from the tissue.

The tissue contact module 236 after that, the processor 210 of the interface module 110 cause the change in the radiometer signal to be compared to a predetermined threshold, e.g. A threshold 235 in the store 230 is stored. The predetermined threshold is preferably chosen so that changes in the radiometer signal caused by non-contact sources such as noise fall below the threshold while changes in the radiometer caused by tissue contact fall above the threshold. Therefore, thresholds may vary from system to system, depending on the particular noise characteristics and the sensitivity of the radiometer. For example, the radiometer signal in the baseline may have a noise level of about ± 0.1V. Calibration can be used to determine that the radiometer signal increases to approximately 0.3 V above baseline when the ICS 122 is brought into contact with tissue. Therefore, the preset threshold 135 are suitably set to an intermediate order between the upper end of the noise level and the average value when the ICS 122 in contact with tissue, e.g. To a value in the range of about 0.11 to 0.29 V in the above example, e.g. Alternatively, the noise level of the radiometer is ± 10% of the baseline, and by calibration it can be determined that the radiometer signal increases by approximately 30% when the ICS 122 is brought into contact with tissue. Therefore, the preset threshold 135 suitably set to an intermediate percentage between the upper end of the noise level and the average value when the ICS 122 in contact with tissue, e.g. In a range of 11 to 29% in the above example, e.g. 15%, 20% or 25% in the example above.

If the processor 210 of the interface module 110 determines that the change in the radiometer signal is higher than the stored preset threshold 235 is, the processor causes the tissue contact indicator 170 to indicate that there is a contact between the ICS 122 and the tissue. For example, the processor 210 a signal to the tissue contact indicator 170 transmitted, that indicates that the ICS 122 in contact with tissue. The tissue contact indicator 170 generates a corresponding indicator in response to the signal, which the physician can interpret as meaning that the ICS 122 was brought into contact with tissue. For example, the tissue contact indicator 170 include a light that illuminates when in tissue contact, and / or may include a speaker that generates sound when in tissue contact, or otherwise signal contact, as discussed above 1A described.

At the in 3A shown method 300 activates the interface module 110 In addition, a patient relay 250 to give ablation energy to the ICS 122 for use in tissue ablation (step 307 ). For example, the processor 210 this in 2A shown patient relay 250 hold in a closed state during operation, allowing ablation energy from the electrosurgical generator 130 via the interface module 110 without delay to the ICS 122 flows when the doctor actuates the generator, and can be the patient relay 250 open only when uncertain conditions are recognized, such as B. with reference to 3C described. In an alternative embodiment, the processor 210 the patient relay 250 during operation in a normally open state and may be based on instructions in a decision module 234 and in step 305 calculated temperature determine whether a continuation of tissue ablation is safe, and then the patient relay close to channel ablation energy to the ICS. In either case, the supply of ablation energy ends after a period of time using the input 133 at the front of the generator 130 or the physician manually turns off the supply of ablation energy. Preferably, step 307 after step 306 carried out. That is, the processor 210 preferably, determines that tissue contact exists and causes the tissue contact indicator to provide an indication of such contact to the physician before enabling ablation energy to be delivered across the patient relay 250 to the ICS 122 provided.

The interface module 110 also generates an analog version of the thermocouple signal and provides the ECG and analog thermocouple signals to the generator 130 ready (step 308 ). Preferably, step 308 during the steps 303 to 307 continuously performed by the interface module and not just at the end of the ablation process. As one skilled in the art knows, the Stockert EP Shuttle or Stockert-70 RF generator can "expect" that certain signals are functioning properly, e.g. For example, those signals that the generator receives during a standard ablation procedure do not require the use of the interface module 110 include. The Stockert EP Shuttle or Stockert 70 RF generator requires an analogue thermocouple signal as input and can optionally accept one or more analog ECG signals. The interface module 110 Thus, the one or more ECG signals generated by the ICS can be accessed via a second I / O port 202 to the Stockert EP Shuttle or Stockert 70 RF generator. As above regarding 2A described, receives the interface module 110 however, a digital thermocouple signal from the ICS 122 , In its standard configuration, the Stockert EP Shuttle or Stockert-70 RF generator is not configured to receive or interpret a digital thermocouple signal. Therefore, the interface module includes 110 the functionality for reconstituting an analog version of the thermocouple signal, e.g. Using the processor 210 and optoelectronics 299 , and to provide this analog signal via the second I / O port 202 to the generator 130 ,

It will be up now 3B Reference is made to the steps of a method 350 for calculating a radiometric temperature using digital signals from a radiometer and a thermocouple and operating parameters. The steps of the process may be performed by a processor 210 based on a temperature calculation model 233 running in a memory 230 is stored (see 2A ). Although some of the signals and operating parameters discussed below are specific to a PSM and an ICS configured for use with RF ablation energy, other signals and operating parameters may be suitable for use with a PSM and an ICS suitable for use are configured with other types of ablation energy. One skilled in the art will be able to modify the methods provided herein for use with other types of ablation energy.

In 3B receives the processor 210 the operating parameters for the thermocouple (TE) and the radiometer from the memory 230 an interface module 110 (Step 351 ). These operating parameters can z. TCSlope, which is the slope of the TE response with respect to temperature; TCOffset, which is the offset of the TE response with respect to temperature; RadSlope, which is the slope of the radiometer response with respect to temperature; TrefSlope, which is the slope of a reference temperature signal generated by the radiometer with respect to temperature; and F, which is a scaling factor.

The processor 210 then receives the digital raw signal from the thermocouple, TCRaw, through a first I / O port 201 and the optoelectronics 299 (Step 352 and calculates the thermocouple temperature, TCT, based on the TCRaw using the following equation (step 353 ): TCT = TCRaw / TCSlope - TCOffset

After that, the processor initiates 210 a temperature display 113 To display the TCT until both of the following conditions are met: The TCT is in the range of 35 ° C to 39 ° C and the ablation energy is provided to the ICS (eg, until step 307 from 3A ). There are several reasons for indicating only the TCT temperature rather than the temperature calculated based on one or more signals from the radiometer until both of these conditions are met. For example, if the temperature TCT measured by the thermocouple is less than 35 ° C, the processor interprets 210 the temperature based on instructions in the decision module 234 to the effect that the ICS 122 is not positioned within a living human body that would have a temperature of about 37 ° C. If the ICS 122 is positioned in the body, power can be safely provided to the radiometer circuit to receive one or more radiometer signals from the processor 210 can use to determine if the ICS 122 in contact with tissue (eg step 306 from 3A ).

As in 3B shown, represents the processor 210 then ablation energy to the ICS 122 ready, z. B. according to the step described above 307 , and receives two raw digital signals from the radiometer through the second I / O port 202 : Vrad, which is a voltage generated by the radiometer based on the temperature adjacent to the ICS; and Vref, which is a reference voltage generated by the radiometer (step 355 ). Note that Vrad and Vref can also be provided by the radiometer at times when these are those which ablation energy to the ICS 122 and that Vrad and / or Vref may represent the one or more radiometer signals received from the processor 210 used to determine if the ICS 122 in contact with tissue (eg step 306 from 3A ).

As in 3B shown, the processor calculates 210 the reference temperature Tref based on Vref using the following equation (step 356 ): Tref = Vref / TrefSlope + TrefOffset

The processor 210 calculates the radiometric temperature Trad based on Vrad and Tref using the following equation (step 357 ): Trad = Vrad / RadSlope - RadOffset + Tref

During operation of the interface module 110 can the processor 210 continuously calculate the TCT and can also calculate the Tref and Trad at times where ablation power is provided to the ICS (which is subject to several conditions, which are further discussed here). The processor 210 can store these values at specific times and / or continuously in memory 230 Save and use the stored values to perform further temperature calculations. For example, the processor 210 the TCT, Tref and Trad to baseline in memory 230 save as the respective values TCBase, TrefBase and TradBase. The processor calculates the current radiometric temperature TradCurrent based on the current, at the second I / O port 202 received Vrad, but using the following equation instead of the baseline reference temperature TrefBase (step 358 ): TradCurrent = Vrad / RadSlope - RadOffset + TrefBase

The processor 210 then calculates a scaled radiometric temperature TSrad based on the baseline thermocouple temperature TCBase, the baseline radiometer temperature TradBase, and the current radiometer temperature TradCurrent using the equation below and initiates the temperature readings 113 to display these for use by the doctor (step 359 ): TSrad = TCBase + (TradCurrent - TradBase) × F

This shows the interface module 110 a temperature for use by the physician, calculated on the basis of one or more signals from the radiometer, and not just on voltages generated by the radiometer and their internal reference, as discussed below 6A to 6B but also based on the temperature measured by the thermocouple.

With reference to 3C is a procedure 360 for controlling an ablation process based on a temperature calculated from one or more signals of a radiometer, e.g. As using the method 350 from 3B calculated, and also on security parameters 232 and a decision module 234 based in a store 230 is stored.

In the process 360 from 3C a slow flow of lavage fluid is introduced through the ICS and then the ICS is positioned in the individual (step 361 ). For example, in embodiments for use with a Stockert-70 RF generator, the generator may automatically initiate a slow flow of lavage fluid to the catheter tip by sending appropriate signals to a CoolFlow lavage pump system connected to the generator when the physician has actuated the generator ,

After being based on a reference from the tissue contact indicator 170 , z. For example, as described above, confirming that the ICS is in contact with tissue, the physician depresses a button on the generator to start the flow of ablation energy to the ICS; this may cause the generator to initiate high sweep fluid flow to the IKS and ablation energy after a 5 second delay to generate (step 362 ). The interface module directs the ablation energy through the patient relay to the ICS, as in step 306 from 3A described.

Based on the calculated and displayed radiometric temperature (see Methods 300 and 350 that in terms of the above 3A to 3B described) the doctor determines the temperature of the tissue volume, which is ablated by the ablation energy (step 363 ). By comparison, a temperature measured by the thermocouple alone during this phase of the process would provide few to no useful information.

The interface module 110 can use the calculated radiometric temperature to determine if the ablation process is performed within safety parameters. For example, the processor 210 security parameters 232 from the store 230 receive. Among other things, these safety parameters may include a shutdown temperature above which the ablation process is considered "unsafe", as this may result in perforation of the heart tissue which is ablated, with potentially serious consequences. The shutdown temperature may be any suitable temperature below which one or more non-safe conditions may not occur, e.g. B. Breaking ("pops"), such as. B. with reference to the 4D to 4E described, or tissue burning, but in which the tissue is still heated sufficiently. An example of a suitable shutdown temperature is 85 ° C, although higher or lower shutdown temperatures may be used, e.g. 65 ° C, 70 ° C, 75 ° C, 80 ° C, 90 ° C or 95 ° C. Instructions in the decision module 234 that too in the store 230 stored, cause the processor 210 To continuously compare the calculated radiometric temperature with the shutdown temperature, and if the radiometric temperature exceeds the shutdown temperature, the processor may set an alarm, open the patient relay, and close the load relay to power over the I / O port 204 leading back to IE, which stops the flow of ablation energy to the ICS (step 364 from 3C ). Otherwise, the processor may allow the ablation process to continue (step 364 ).

The ablation process ends (step 365 ) z. For example, if the doctor clicks on the corresponding button on the generator 130 pushes or if the generator 130 the ablation energy automatically shuts off at the end of a predetermined period of time.

It will now be on the 4A to 4E Reference is made to describing illustrative data obtained during experiments using an interface module constructed in accordance with the present invention. These data were obtained using a non-modified Stockert EP shuttle generator with an integrated irrigation pump and a catheter containing the PSM 121 and the ICS 122 contained as below with respect to the 5A to 6B described with the interface module 110 connected is.

4A Figure 12 shows the change of various signals over time collected during a process where the ICS ablation peak 122 immersed in a saline tank containing a tissue sample maintained at a constant temperature of about 49.5 ° C and having dielectric constants similar to those of a living blood or tissue. The ablation tip of the ICS 122 was manually brought into contact with tissue several times and released from it. A signal 401 , this in 4A is shown corresponds to a radiometer signal Vrad (in units of volts, right-hand y-axis of the graph), a signal 402 corresponds to the thermocouple temperature (in units of ° C, left-hand y-axis of the graph) and a signal 403 corresponds to the display temperature Tdisplay (also in units of ° C, left-hand y-axis of the graph). The signals 401 . 402 and 403 were collected without operating the Stockert EP shuttle generator, making changes to the Vrad while the IKS 122 which was contacted with the tissue, could be attributed to the difference between the dielectric constants of the saline solution of the tissue and not temperature changes.

As in 4A As can be seen, the radiometer signal begins 401 at a baseline 404 by 2.95 V; The specific values of this baseline depend, among other things, on the dielectric constant and the temperature of the saline solution in which the ICS 122 immersed, and the sensitivity of the radiometer. The radiometer signal 401 has a noise level 405 about ± 0.05 V around the baseline 404 , which can be attributed to an arbitrary noise in the Radiometerelektronik. During the periods between approximately 20 to 32 seconds, 40 to 52 seconds, 60 to 72 seconds, and 80 to 92 seconds, it can be observed that the radiometer signal 401 from the baseline 404 quickly to a higher level 406 increases from about 3.37V. Since the tissue has the same temperature as the saline solution, there may be a change in the radiometer signal 401 to the level 406 the different dielectric constant of the tissue in the Compared to saline solution. Therefore, a contact between the ICS 122 and the tissue in the tank based on changes in the radiometer signal from the baseline 404 to the level 406 be identified quickly. In addition, a pre-defined threshold 407 be defined on the basis of such observations, between the upper end of the noise 405 and the level 406 which is indicative of a tissue contact, and that in a store 230 stored and by a processor 210 of the interface module 110 used at a later date to determine if the ICS 122 in contact with tissue. Thus, such an operation essentially calibrates the ICS 122 in terms of tissue contact. Preferably, the temperature and dielectric constants of the materials used during such calibration are selected to be relatively similar to those of a human's blood and tissue, such that the baseline 404 , the level 406 and the predefined threshold 407 based on the expected temperatures and dielectric constants measured by the radiometer during an actual ablation process.

4B Figure 12 shows the change of various signals over time collected during an ablation procedure using an ICS 122 was placed on exposed femur of a living dog and the Stockert EP shuttle generator was actuated to apply RF energy of 20 W for 60 seconds. A Luxtron probe was also inserted into the thigh of the dog at a depth of 3 mm. Luxtron probes are considered to provide accurate temperature information, but are impractical for normal use in cardiac ablation procedures because such probes can not be placed in the heart of a living being.

4B shows the change of various signals over time collected during the ablation process. A signal 410 corresponds to a scaled radiometric temperature TSrad; a signal 420 corresponds to the thermocouple temperature; a signal 430 corresponds to a temperature measured by the Luxtron probe; and a signal 440 corresponds to the power generated by the Stockert EP shuttle generator.

As in 4B apparent, indicated the power signal 440 in that RF power was applied to the tissue of an individual, starting at a time of about 40 seconds and ending at a time of about 100 seconds. The radiometric temperature signal 410 indicates a sharp rise in temperature, starting at around 40 seconds, from a baseline in one area 411 from about 28 ° C to a maximum in one area 412 of about 67 ° C, followed by a gradual drop in one area 413 , starting at about 100 seconds. The characteristics of the radiometric temperature signal 410 are similar to those of the Luxtron probe signal 430 , which likewise shows a temperature increase starting at about 40 seconds to a maximum value just before 100 seconds, and then a temperature drop, starting at about 100 seconds. This similarity indicates that the radiometric temperature has a similar accuracy to the Luxtron probe. For comparison, the thermocouple signal shows 420 a significantly lower temperature rise, starting at about 40 seconds, followed by a low plateau in the range of 40 to 100 seconds, and then a decrease, starting at about 100 seconds. The relatively weak response of the thermocouple and the relatively strong and accurate response of the Luxtron thermocouple indicate that an unmodified Stockert EP shuttle generator using an interface module 110 can be successfully retrofitted, constructed in accordance with the principles of the present invention to provide useful radiometric temperature information to a physician for use in an ablation procedure.

4C Figure 12 shows signals obtained during a similar experimental procedure, but in which two Luxtron probes were implanted into the tissue of one animal, the first at a depth of 3 mm and the second at a depth of 7 mm. The Stockert EP shuttle generator was activated and the RF power was manually modulated to between 5 and 50 W using the power control knob on the front panel of the generator. In 4C is the radiometer signal with 460 expelled, 3 mm Luxtron with 470 and 7mm Luxtron with 480 , It can be seen that the radiometer and 3mm Luxtron signals 460 . 470 show relatively similar amplitude changes with respect to each other resulting from periodic heating of the tissue by RF energy. It can be observed that the 7 mm Luxtron signal 480 has a slight periodicity, but a much lower modulation than the radiometer and 3 mm Luxtron signals 460 . 470 , This is due to the fact that 7 mm Luxtron is sufficiently deep inside the tissue that an ablation energy at this depth does not substantially penetrate directly. Instead, it can be observed that the tissue warms slowly at 7 mm as a function of time, while heat deposited in shallower sections of the tissue gradually diffuses into a depth of 7 mm.

In addition, a series of cardiac ablation procedures on living humans using the above with respect to the 4B to 4C described experiment setup, but without the Luxtron probes performed. All of them suffered from atrial flutter, were enrolled for treatment of this for conventional cardiac ablation procedures, and agreed to the physician's use of the interface box and ICS during procedures. The procedures were performed by a physician who introduced the ICS into the endocardium of the individuals using conventional techniques. During the procedures, the doctor was not allowed to see the temperature calculated by the interface module. Therefore, the physician performed the procedures in the same manner as would be done on a system containing a conventional RF ablation catheter connected directly to a Stockert EP shuttle generator. The temperature calculated by the interface module during the various procedures has been made available to the physician for review at a later date. The physician performed a total of 113 ablation procedures on five people using the experimental set-up outlined above.

The 4D to 4E show data obtained during sequential ablation procedures performed using the experimental setup on a single individual. In particular shows 4D the change of the signal 415 , which corresponds to the scaled radiometric temperature TSrad, over time as well as the change of the signal 421 corresponding to the thermocouple temperature over time during the tenth ablation process performed on the individual. During the process, an RF power of about 40 W was applied for 60 seconds (between about 20 seconds and 80 seconds in 4D ) was applied to the heart tissue of the individual and the physician had a target temperature 445 of 55 ° C, to which the heart tissue should be heated to adequately interrupt an abnormal pathway causing the atrial flutter of the individual. It can be seen that the scaled radiometric temperature signal 415 , this in 4D data smoothing varied between about 40 ° C and 51 ° C while applying RF power. For comparison, the thermocouple temperature 421 As expected, essentially no useful information about tissue temperature is available during the procedure. In particular, the target temperature became 445 The doctor at 55 ° C during the procedure never reached, although on the basis of his perception of the procedure, the doctor assumed that such a temperature had been reached. As the target temperature 445 was not reached, the tissue was not sufficiently heated during the procedure to disrupt an abnormal pathway. Failure to reach the target temperature may be due to inadequate contact or insufficient force of the ablation tip of the ICS and heart tissue of the subject, the condition of the heart surface, inadequate performance, and the like.

4E shows the change of a signal 416 , which corresponds to TSrad, over the time as well as the change of the signal 422 corresponding to the thermocouple temperature over the time during the eleventh ablation process occurring on the same individual as in 4D was carried out. During this process, again an RF power of about 40 W was applied for 60 seconds (between about 20 seconds and 80 seconds in FIG 4D ) was applied to the heart tissue of the individual and the physician again had a target temperature 445 from 55 ° C. It can be seen that the scaled radiometric signal 416 , which was again subjected to data smoothing, varied between about 55 ° C and 70 ° C while RF power was applied, the thermocouple temperature 421 however, in turn, provides essentially no useful information. Here, the physician attributed the higher temperature tissue temperature achieved during ablation to better contact between the ablation tip of the ICS and the heart tissue of the subject. However, it can be seen that the temperature - even when RF power was applied to the tissue - varied relatively rapidly over time, e.g. From about 70 ° C at about 35 seconds to about 56 ° C at 40 seconds, which can be attributed to variations in contact quality between the ICS and the heart tissue of the subject.

The results of the ablation procedures performed on five individuals are summarized in the table below: total % Total ablation Number of patients 5 Number of ablations 113 Number of ablations that did not reach the target temperature of 55 ° C 50 44% Number of ablations that reached a high temperature shutdown of 95 ° C 13 12% Number of pops 3 3% Number of successful atrial fibrillation treatments 5 100%

As can be seen from the above table, 44% of the ablation procedures did not reach the clinician's target tissue temperature of 55 ° C. Therefore, it is likely that this percentage of operations resulted in inadequate heating for disruption of the one or more anomalous pathways. However, although many of the ablation procedures failed, the physician repeated the ablation procedures sufficiently frequently to achieve 100% treatment of atrial flutter of the individuals. It is believed that displaying the calculated temperature to the physician during the ablation procedures will allow the physician much greater access to the quality of contact between the ablation tip of the ICS and the heart tissue of the subject and thereby maintain the tissue sufficiently above the target tissue temperature for a desired period of time This reduces the need for the physician to repeatedly perform multiple ablation procedures on the same individual to achieve the desired treatment.

As shown in the above table, 12% of the ablation procedures triggered the high temperature shutdown, as in 3C illustrated. Here, the shutdown temperature has been set to 95 ° C. However, it was observed that at this shutdown temperature "pops" formed during three of the ablation procedures. A "pop" occurs when the blood boils due to excessive localized heating by ablation energy, resulting in the formation of a rapidly expanding bladder of hot gas, which can catastrophically damage the heart tissue. It is assumed that a lower shutdown temperature, z. B. 85 ° C, can inhibit the formation of such "pops".

Other components that work in conjunction with the interface module 110 can be used in the present invention, for. The PMS 121 and the ICS 122 of the catheter 120 , are now referring to the 5A to 6B briefly described.

In 5A is a patient interface module (PSM) 121 described that may be connected to the integrated catheter tip (ICS) described below with reference to the 6A to 6B is described. The PSM 121 contains an interface module connector 501 that with a front panel 111 of the interface module 110 can be connected as with reference to 1A described; a PSM circuit 502 referred to below with reference to 5B is described in more detail; an ICS connector 503 that with the catheter 120 can be connected; and a PSM cable 504 extending between the interface module connector 501 and the PMS circuit 502 extends. The PSM 121 is preferably, but not necessarily, designed to remain outside the sterile field during the ablation process and is optionally reusable with multiple ICS.

5B shows internal components of the PSM circuit 502 schematic and contains a first I / O port 505 that is configured to be with the catheter 120 is connected, for. B. via an ICS connector 503 , and a second I / O port 506 that is configured to work with the interface module 110 is connected, for. B. via the PSM cable 504 and the interface module connector 501 ,

The PSM circuit 502 receives at the first I / O port 505 an analogue thermocouple (TE) signal, analog raw radiometer signals, and analog ECG signals from the catheter 120 , The PSM circuit 502 includes a TE signal analog-to-digital (A / D) converter 540 configured to convert the TE analog signal into a TE digital signal and the TE digital signal via the second I / O port 506 to the interface module 110 provides. The PSM circuit 502 contains a number of components that are configured to convert the analog raw radiometer signals into a usable digital form. For example, the PSM circuit may be a radiometric signal filter 510 configured to filter residual RF energy from the analog radiometer raw signals; a radiometric signal decoder 520 configured to convert the filtered signals into analog versions of the Vref and Vrad signals discussed above with respect to FIG 3B were mentioned; and a radiometric signal A / D converter 530 configured to convert the analog Vref and Vrad signals into Vref and Vrad digital signals and send these signals to the second I / O port for transmission to the interface module 110 provides. The PSM circuit 502 also routes the ECG signals to the second I / O port 506 for transmission to the interface module 110 ,

At the second I / O port 506 receives the PSM circuit 502 RF ablation energy from a generator 130 (eg a Stockert EP Shuttle or Stockert 70 RF generator) via the interface module 110 , The PSM circuit 502 conducts this RF ablation energy across the first I / O port 505 to the catheter 120 , The PSM circuit 502 receives at the second I / O port 506 In addition, a clock signal from an RF circuit within the interface module 110 is generated, as described above with reference to 2 B and routes the clock signal to the first I / O port 505 for use in controlling a microwave circuit in the ICS 122 as described below.

It will now be on the 6A to 6B Reference is made in which an integrated catheter tip (ICS) 122 for use with the interface module 110 of the 1A to 2 B and the PSM the 5A to 5B is described. Further details on the components of the ICS 122 can that U.S. Patent No. 7,769,469 by Carr, the entire contents of which are hereby incorporated by reference, as well as the U.S. Patent Publication No. 2010/0076424 also by Carr ("the Carr Publication"), the entire contents of which are hereby incorporated by reference. The unit described in the above mentioned patent and publication contains no thermocouple and no ECG electrodes, preferably in the ICS 122 included for use with the interface module 110 is configured.

As described in the Carr publication and in the 6A to 6B shown contains the ICS 122 an inner or middle ladder 103 that of a conductive carrier or insert 104 will be carried. The carrier 104 may consist of a cylindrical metal body with an axial passage 106 be formed, who is the leader 103 receives. Upper and lower portions of this body, which extend inward from the ends, can be milled away to pass 106 and the leader 103 to expose therein and upper and lower substantially parallel planes 108a and 108b to build. The level 108a can coplanare rectangular areas 108aa included on opposite sides of the conductor 103 can be spaced near its upper portion. Similarly, the level 108b two coplanar rectangular areas 108Bb included on opposite sides of the conductor 103 can be spaced near its bottom. Thus, the carrier can 104 a middle segment 104a containing the planes, and distal and proximal end segments 104b respectively. 104c which remain cylindrical, except that a vertical groove 107 in the proximal segment 104c can be formed.

The middle conductor 103 can be coaxial within the passage 106 be fixed using an electrically insulating sleeve or socket 109 , z. B. PTFE, by press fit into the passage 106 at a distal end segment 104b of the wearer and by a weld on the passageway wall or by an electrically conductive sleeve or bush (not shown) on the support proximal to the segment 104c , This causes a short circuit between the conductor 103 and the carrier 104 at the proximal end of the carrier while an open circuit may be present therebetween at the distal end of the carrier. In the middle carrier segment 104a can the walls 106a of the passage 106 from the middle ladder 103 be spaced. This forms a quarter-wave stub S, as in U.S. Patent No. 7,769,469 and in the U.S. Patent Publication No. 2010/0076424 described in more detail. The leader 103 contains a distal end segments 103a extending a selected distance beyond the distal end of the carrier 104 extends, and a proximal end segment 103b extending from the proximal end of the ICS 122 extends and connects to the middle conductor of the cable 105 connects that for a connection with the PSM 121 is configured.

As in 6B shown is at the upper and lower levels 108a and 108b of the carrier 104 a pair of opposed, parallel, mirror-image, generally rectangular plates 115a and 115b attached. Every plate 115a . 115b can a thin, z. B. 0.005 inch (0.013 cm) thick substrate 116 included, which is formed of an electrically insulating material having a high dielectric constant. Axially centered conductive longitudinal strips 117 with a width of preferably 0.013 to 0.016 mm, which extends over the entire lengths of the substrates 116 extend are on the opposite or facing surfaces of the substrates 116 printed, plated or otherwise formed on this. In addition, the opposite or opposite surfaces of the substrates 116 with conductive layers 118 plated, the z. B. are made of gold. The margins of the layers 118 wrap around the side edges of the substrates.

When the ICS is put together, the plate can 115a to the upper level 108a of the carrier 104 be placed and the bottom plate 115b will be equally at the lower level 108b placed so that the middle conductor 103 from above and below through the conductive strips 117 the top and bottom plates are touched and the side edges of the layer 118 of these plates the carrier segment 104a touch. A suitable conductive epoxy or binder may be applied between these contact surfaces to hold the plates in place.

At least one of the plates, z. B. plate 115x , also acts as a support surface for one or more monolithic integrated circuit chips (MMICs), e.g. Eg chips 122 and 124 , The one or more chips may include a coupling capacitor connected to the center conductor via a line (not shown) 103 connected, and contain the usual components of a radiometer, z. A thickness switch, a noise source to provide a reference temperature, amplifier stages, a bandpass filter to form the radiometer bandwidth, further amplification stages if required, a detector and buffer amplifier. Due to the relatively low profile of the present ICS 122 For example, the above chip components may be arranged in a chain of four chips. The one or more chips may be attached to the metal layer via a suitable conductive adhesive 118 of the plate 115a be attached so that the layer is used as described above 104 grounded, can act as a ground plane for these chips. The plates also conduct heat away from the chips to the conductor 103 and carriers 104 , Different lines (not shown) connect the chips to each other and other lines 125b extend through carrier slots 107 and connect the last chip 124 in the chain, ie the radiometer output, with corresponding conductors of the cable 105 that to the PSM 121 leads.

A tubular outer conductor 126 can on the carrier 104 be slipped over one end thereof so that it engages well with the wearer with its proximal and distal ends converging with the respective ends of the wearer (not shown). The leader 126 can be fixed in place by a conductive epoxy or binder around the carrier segments 104b and 104c is applied.

The ICS 122 In addition, a ring-shaped dielectric spacer 137 included, the z. B. made of PTFE, at the distal end of the carrier 104 is centered and the conductor segment 103a surrounds. The spacer can have a slot 137a that allows it to attack that conductor segment from its side. The spacer 137 can through a conductive cuff 136 held in place, which encloses the spacer and is long enough to slidably over a distal end segment of the outer conductor 126 attack. The cuff 136 can around this conductor and the carrier segment 104b Pressed to hold them in place and electrically connect with all these elements.

The distal end of the ICS 122 can from a conductive tip 142 be shut off, which may be T-shaped in axial section. That means the top 142 a disk-shaped head 142a , which forms the distal end ICS, and an axially extending tubular neck 142b can have. The conductor segment 103a is long enough to reach over the distal end of the spacer 137 out into the axial passage in the throat 104b to extend. The tip may be held in place by a conductive adhesive that surrounds the distal end of the conductor segment 103a and at the distal end or edge of the cuff 136 is applied. When the tip is in place, form the conductor segment 103a and the top 104 a radiometric receiving antenna, as in U.S. Patent No. 7,769,469 and in the U.S. Patent Publication No. 2010/0076424 described in more detail.

The ICS 122 In addition, a dielectric sheath can be used 144 included, over the rear end of the outer conductor 126 attack and can be pushed forward until its distal end 144a a selected distance behind the distal end of the tip 142 is spaced. The ladder 103 and 126 the ICS 122 Form an RF transmission line through the top 104 is limited. If the ICS 122 is functional, the transmission line can use energy to heat the tissue only from the non-isolated segment of the probe between the tip 104 and the distal end 144a of the coat 144 radiate. This segment thus represents an RF ablation antenna.

The proximal ends of the middle conductor segment 103b , the manager 126 and the coat 144 can each with the inner and outer conductors and an outer sheath of the cable 105 connected to the PSM 121 leads. Alternatively, these elements can be extensions of the corresponding components of the cable 105 be. Anyway, this cable connects 105 the middle ladder 103 to the output of a transmitter which receives an RF heating signal at a selected heating frequency, e.g. B. 500 GHz, transmits to the RF ablation antenna.

As in 6C shown can be an ics 122 In addition, first, second and third ECG electrodes 190 included on the outside of a coat 144 are arranged, as well as a thermocouple 191 which is designed to keep the temperature of blood and tissue in contact with the ICS 122 detected. From the electrodes 190 and the thermocouple 191 Signals generated along a cable 105 be provided with a PSM 121 connected is.

If desired, the cable 105 In addition, a probe steering wire 145 contain, the front end 145a on the wall of a passage 146 in a carrier segment 104c can be attached.

Preferably, a helical through-slot 147 in a cuff 136 provided as in the 6A to 6B shown. The sleeve material remaining between the slot turns substantially forms a helical wire 148 , a spacer 137 bridged. It was found that the wire 148 improves the microwave antenna diagram of the receive radiometric antenna without significantly degrading the RF heating pattern of the RF ablation antenna.

The middle or inner conductor 103 may be a solid wire or is preferably formed as a tube, which is the conductor 103 conveying a flushing fluid or refrigerant to the interior of a probe tip 142 for a distribution out of this through radial passages 155 in a lace head 142a to allow the with the distal end of the axial passage in a tip neck 142b communicated.

If plates 115a and 115b on the upper and lower levels 108a respectively. 108b a carrier 104 placed and attached to these may be conductive strips 117 . 117 of these elements electrically with the middle conductor 103 in the upper and lower part of it, so that the conductor 103 the middle lines for a plate-like transmission line forms whose mass surface layers 118 . 118 contains.

When ablation energy to the ICS 122 is provided within the substrate 116 a microwave field that is between the middle conductor 103 and the layers 118 . 118 is concentrated. As noted herein, conductive epoxy is preferably between the conductor 103 and the strip 117 applied to ensure that there are no air gaps, since such a gap would have a significant impact on the impedance of the transmission line, since the highest field parts of the conductor 103 are nearest.

The plates 115a . 115b and the segment of the leader 103 together with the carrier 104 form a quarter wave (λ _R / 4) stub S, which is at the frequency of a radiometer circuit 124 can be adjusted, for. 4 GHz. The quarter-wave stub S can be applied to the average frequency of the radiometer circuit together with components in chips 122 . 124 can be adjusted to form a low pass filter in the signal transmission path to the RF ablation antenna, while other components of the chips can form a high pass or band pass filter in the signal reception path from the antenna to the radiometer. The combination forms a passive diplexer D which prevents the lower frequency transmitter signals on the signal transmission path from an antenna T from reaching the radiometer while at the same time isolating the path to the transmitter from the antenna with respect to the higher frequency signals on the signal reception path.

The impedance of the quarter wave stub S depends on the K value and a thickness t of the substrates 116 the two plates 115a . 115b and the distance of the middle conductor 103 from the walls 106a . 106b of the passage 106 in the middle carrier segment 104a from. As the middle conductor 103 is not surrounded by a ceramic shell, these walls can be moved closer to the central conductor, making it possible to accurately adjust the impedance of the exposed substrate transmission line and at the same time the overall diameter of the ICS 122 to minimize. As noted above, the length of the stub line S can also be reduced by having the substrate 116 is made of a dielectric material having a relatively high K value.

In a working version of the ICS 122 , which is only about 0.43 inches (1.09 cm) long and about 0.08 inches (0.20 cm) in diameter, the components of the ICS have the following dimensions: component Dimension in inches (centimeters) ladder 103 Outer diameter: 0.020 (0.05 cm) Inner diameter (if hollow): 0.016 (0.04 cm) substratum 116 (K = 9,8) Width: 0.065 (0.16); Thickness t: 0.005 (0.01 cm) strip 117 Width: 0.015 (0.03 cm) Air gap between 103 and everybody 106a 0.015 (0.03 cm)

Thus, the total length and the diameter of the ICS 122 which is a useful feature for units configured for percutaneous use.

Although various illustrative embodiments of the invention are described above, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the invention. For example, even though the interface module has been described primarily with reference to use with an electrosurgical RF generator and the PSM and ICS, as shown in FIGS 5A - 6B as will be appreciated, the interface module may be adapted for use with other ablation power sources and other types of radiators. In addition, the radiometer may contain components in the ICS and / or PSM and does not necessarily have to be wholly located in the ICS. In addition, the functionality of the radiometer, the ICS and / or the PSM may optionally be included in the interface module. The appended claims are intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4190053 [0007]
• US 7769469 [0008, 0102, 0104, 0110]
• US 2010/0076424 [0102, 0104, 0110]

Claims (25)

A system for facilitating the detection of contact with a target tissue of an individual, comprising: a catheter comprising a radio frequency electrode and a radiometer; and a processor configured to receive a signal from the radiometer and provide an output indicative of contact between the radiofrequency electrode and the subject tissue of the subject based at least in part on tissue properties determined from the signal received by the radiometer , The system of claim 1, wherein the processor is configured to regulate operation of the radio frequency electrode based on the output indicative of contact between the radio frequency electrode and the subject tissue of the subject. The system of claim 1 or 2, wherein the system is operatively connected to an electrophysiology monitoring system. The system of any preceding claim, wherein the system is configured to provide confirmation of the contact between the radio frequency electrode and the subject tissue of the subject to a user of the system. The system of claim 4, wherein the contact confirmation is provided on a visual display or acoustically. The system of any one of the preceding claims, wherein the processor holds the radio frequency electrode in a deactivated state, except when contact between the radio frequency electrode and the target tissue is confirmed. The system of any one of the preceding claims, further comprising a flushing system comprising a pump in fluid communication with a fluid channel of the catheter, the flushing system configured to selectively communicate flushing fluid through the fluid channel of the catheter and at least one flushing fluid port of the catheter is supplied to the fluid channel of the catheter during use. The system of any preceding claim, wherein the catheter comprises an integrated catheter tip comprising a generally tubular shape and a flat distal end. The system of any one of the preceding claims, wherein the radio frequency electrode and the radiometer are positioned in an integrated catheter tip at a distal end of the catheter. A system for facilitating the detection of contact with a target tissue of an individual, comprising: a processor, wherein the processor is configured to receive a signal from a radiometer positioned at a tip along a distal end of a catheter, and to provide an output indicative of contact between the tip of the catheter and target tissue of an individual partially based on tissue characteristics determined from the signal received by the radiometer. The system of claim 10, wherein the processor is configured to control operation of an ablation element of the catheter based on an output indicative of contact between the tip of the catheter and the target tissue of the subject. The system of claim 10 of 11, wherein the system is configured to provide confirmation of the contact between the catheter tip and the subject tissue of the subject to a user of the system. The system of claim 12, wherein the contact confirmation is provided on a visual display or acoustically. The system of claims 10 to 13, further comprising a flushing system including a pump in fluid communication with a fluid channel of the catheter, the flushing system being configured to selectively deliver flushing fluid through the fluid channel of the catheter and at least one flushing fluid port of the catheter tip Fluid communication with the fluid channel of the catheter during use supplies. A system for facilitating the detection of contact with a target tissue of an individual, comprising: a processor, wherein the processor is configured to receive a signal from a radiometer carried by a medical instrument and to provide an output based on contact between a portion of the medical instrument and target tissue of an individual based at least in part tissue properties determined by the signal received by the radiometer. The system of claim 15, wherein the processor is configured to regulate operation of a power supply element of the medical instrument based on the output indicative of contact between the portion of the medical instrument and the target tissue of the individual. The system of claim 15 or 16, wherein the system is configured to provide confirmation of the contact between the portion of the medical instrument and the target tissue of the subject to a user of the system. The system of claims 15 to 17, wherein the medical instrument comprises a catheter comprising a irrigation pump in fluid communication with a fluid channel of the catheter, the irrigation pump being configured to selectively deliver irrigation fluid through the fluid channel of the catheter and at least one irrigation fluid port of the catheter tip in fluid communication with the fluid channel of the catheter during use. The system of any one of claims 15 to 18, further comprising the medical instrument, the medical instrument comprising an ablation catheter configured to deliver energy sufficient to ablate the target tissue upon activation by an ablation energy source, after the contact indicative of the contact has been provided by the processor. The system of claim 15, further comprising the medical instrument, wherein the medical instrument comprises a power delivery catheter configured to supply energy to the target tissue upon activation by a power source after the output indicative of the contact Processor was provided. The system of claim 11, wherein the ablation element is configured to deliver at least one of radiofrequency energy, ultrasound energy, microwave energy, and cryosurgical energy. The system of claim 16, wherein the energy delivery element is configured to deliver at least one of radiofrequency energy, ultrasound energy, microwave energy, and cryosurgical energy. The system of any one of the preceding claims, wherein the processor is configured to calculate a temperature of a target tissue at a depth at least in part based on a signal generated by the radiometer and a signal from a temperature measurement unit. The system of claim 23, wherein the temperature measuring unit comprises a thermocouple. The system of claim 1, wherein the processor is configured to calculate a temperature of target tissue at a depth, and wherein the processor is configured to supply power to the radio frequency electrode based, at least in part, on a comparison between the calculated temperature of target tissue and a shutdown temperature.

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