System and method for processing positioning signals

Abstract

Methods and systems for determining the position of one or more distal end portions of a catheter are disclosed. In an embodiment, the method includes processing positioning signals transmitted by a transmitter-receiver utility having a first clock and received by a position sensor at a distal end portion of the catheter. The processing may be performed by a signal processor having a second clock that is not synchronized with the first clock of the transmitter-receiver utility. The processing includes determining a clock rate ratio between clock rates of the first clock and the second clock; determining a time lag between the first clock and the second clock; and determining a relative phase of the received signal while compensating for the time lag between the clock rate ratio and the clocks such that the determined phase is adjusted relative to the first signal clock of the transmitter receiver utility. Thus, the position of the catheter distal end portion may be determined based on the relative phases.

Description

Technical Field

[0001] The present invention is in the field of signaling of medical devices and, in particular, relates to determining the position of multiple medical instruments or other portions of multiple medical instruments during a medical procedure. Background Art

[0002] A wide range of medical procedures involve multiple medical devices on and / or in the patient's body. These medical devices can be, for example, one or more catheters, and in many cases, a single catheter includes multiple parts / segments, which can be, for example, one or more flexible segments (such as its flexible arms / splines) and / or medical devices (e.g., sensors / probes, electrodes such as EEG electrodes, ablation devices and / or other devices) that can be distributed on the flexible segments. During the medical operation, the flexible segments of such catheters can be bent / curved to simultaneously approach / contact different parts of the anatomical structure being treated for sensing (mapping) and / or treating tissue at those different parts by the medical devices thereon, in some cases simultaneously. The use of catheters comprising multiple flexible segments / portions has proven to be a very useful medical procedure for treating arrhythmias. Arrhythmias, particularly atrial fibrillation, have always been common and dangerous medical diseases, especially in the elderly population.

[0003] Diagnosis and treatment of arrhythmias include mapping the electrical properties of cardiac tissue (particularly the endocardium and cardiac volume), and selectively ablating cardiac tissue by applying energy. Typically in such procedures, one or more catheters having multiple parts (such as flexible segments / splines) are inserted into the patient. In some cases, medical devices arranged on these multiple parts are operated to perform multiple related operations, such as electrocardiogram (ECG) mapping, tissue ablation, temperature sensing / mapping, and / or image / ultrasound sensing. Some catheters are specifically designed to be placed in specific parts of the anatomical structure (e.g., ventricle, coronary sinus, esophagus, atrium, ventricle), and include multiple flexible segments / parts that can conform to the shape of the anatomical structure of the body part being treated, and optionally have multiple instruments arranged at different parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] In order to better understand the subject matter disclosed herein and to illustrate how it may be implemented in practice, various embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0005] Figure 1 is a schematic diagram illustrating a catheter-based mapping and ablation system according to an embodiment of the present invention;

[0006] Figure 2 is a schematic diagram of a catheter having a plurality of portions / medical devices at its distal end and position sensors associated therewith;

[0007] Figure 3A is a block diagram illustrating the configuration of a positioning system 100 according to an embodiment of the present invention;

[0008] Figure 3B is a flow chart illustrating a method 200 of determining a position of a medical device and / or a distal portion thereof, according to an embodiment of the present invention;

[0009] In some drawings, similar reference numerals are used to represent similar modules / elements of the present invention or elements / modules having similar functions. Therefore, unless otherwise indicated, descriptions of modules / elements with reference to a specific embodiment of the present invention should be understood to apply to all embodiments of the present invention in which such modules / elements are incorporated. DETAILED DESCRIPTION

[0010] With the advancement of medical technology, the number of medical devices and medical instruments involved in medical procedures and arranged, placed or moved in a patient's body space has increased significantly. For example, in some medical procedures, catheters (such as intracardiac ECG mapping catheters and / or ablation catheters) and / or medical instruments having multiple distal portions (such as movable / flexible sections (e.g., splines)) are used. For example, in many cases, the medical instrument is arranged at various movable / flexible sections at the distal end of the catheter, such as a shaft, a distal actuator, a spline and / or various other sections arranged at its distal actuator. The movable / flexible section of the catheter can be adapted to bend / expand during a medical procedure (e.g., to accommodate the volume of the body anatomy being treated / monitored and / or to bring a medical device thereon into contact with or close proximity to a wall / boundary of the body anatomy being treated / monitored). Such techniques are used, for example, to facilitate enabling substantially simultaneous mapping and / or treatment of several tissue regions of an anatomical structure. To this end, a large number of medical devices (such as ECG electrodes, ablation utilities / devices, or other devices) can be arranged at multiple movable / flexible sections of the catheter and can, for example, be used to enable a physician to simultaneously capture / map electrical activity from multiple locations in the heart chamber and / or simultaneously ablate specific tissue regions thereof.

[0011] In order to accurately perform such medical procedures, the position of medical devices equipped at different flexible / movable sections of the catheter and / or the position of one or more of the flexible / movable sections of the catheter itself should be monitored / tracked relative to the treated / probed anatomical structures of the patient's body.

[0012] For the sake of clarity, hereinafter, the phrase distal portion of medical device / catheter and variations thereof are used to refer to the part / element / segment that is arranged at the distal end / end of the medical device / catheter, and its position should be determined during a medical procedure. In this regard, it should be understood that the phrase distal portion can encompass any one of the flexible / movable section of the distal end of the catheter and / or the medical instrument arranged thereon, which is associated with a position sensor that is positioned near it and can provide data / signals indicating the corresponding position of the distal portion. The term position is used in this article to refer to any one of the positioning, orientation, or both of a medical device or its distal portion. For example, in some cases, it may not be necessary to determine the positioning of a medical device or a part thereof, but only to determine its orientation, or vice versa, and system of the present invention may be suitable for / capable of operating to achieve the same purpose.

[0013] To achieve this, the medical device / catheter can be configured so that its different distal end portions, or some of them, include corresponding position sensors capable of receiving positioning signals (e.g., electromagnetic signals), by which the positions of the different portions can be determined. These received positioning signals should then be processed in order to monitor / track the positions of the different portions of the distal end of the catheter during the medical procedure. Thus, in this way, valuable information about the positions of the different portions of the medical device / catheter can be provided to the physician during the medical procedure (e.g., in real time).

[0014] In view of the foregoing, there is a need in the art for systems and methods capable of determining the positions of multiple portions of the distal end of a catheter or other medical device having different portions that are movable relative to each other and / or relative to the body / shaft of the device. Conventional hardware for determining the position of a medical device is generally limited in its ability to determine multiple discrete positions from multiple position sensors, such as those provided on different distal end portions of the aforementioned type of catheter (since various catheters of this type may include between a few and dozens of position sensors). For this reason, conventional hardware for determining the position of a medical device is generally not suitable for connection to medical devices, such as catheters, that have a relatively large number of position sensors whose positions need to be determined. In fact, conventional hardware typically includes a transmitter for transmitting positioning signals that can be received by multiple position sensors of such catheters or other medical devices, but has limited channels for collecting positioning signals received by multiple position sensors of such devices and is not suitable for simultaneously processing positioning signals provided by multiple position sensors embedded in some advanced medical devices, such as splined or basket-type catheters that have multiple, separately movable portions at their distal ends / distal tips.

[0015] Thus, the present invention provides novel systems and methods for addressing these problems, enabling the capabilities of existing medical device positioning hardware to be expanded, thereby enabling the position of multiple parts of a medical device to be determined (e.g., simultaneously) while utilizing and synchronizing with positioning signals provided / transmitted by existing conventional medical device positioning hardware. Advantageously, the present invention facilitates the positioning of a relatively large number of position sensors, which may not be facilitated by conventional positioning hardware, while not requiring the replacement of existing positioning hardware (e.g., which may already be deployed) and not requiring the addition of positioning signal transmitters or the transmission of additional positioning signals. Thus, the position of a large number of medical devices / instruments or parts thereof can be determined during a medical procedure in a cost-effective manner without overcrowding a medical facility due to additional electromagnetic signals.

[0016] refer to Figure 1 , which shows an example catheter-based mapping and ablation system 10. The system 10 includes or is connectable to a plurality of medical devices 14 and may include, for example, catheters 36 and 37, the positions of which and preferably the positions of their respective distal portions 35 are to be determined by the system 10. It should be noted that the distal portion 35 whose position is to be determined may include the body (e.g., the shaft of the catheter) 14H of the medical device 14 (such as catheter 36 or 37), and / or one or more flexible / movable sections / splines 22 thereof, and / or a medical device 26 provided at the distal end of the medical device 14 (e.g., movable relative to the body / shaft of the medical device 14), and its position may therefore not be accurately determined based solely on measurements of the position of the medical device itself. In the non-limiting examples provided herein, the distal portion 35 includes some of the medical device 26 and / or the movable section / spline 22 at which the distal portion is provided in the catheter 36 and / or 37. It should also be noted that the movable section 22 may be implemented using various configurations such as flexible splines as shown in the figures, or by other configurations utilizing, for example, pivots, flexible joints, extendable / retractable shafts, or any other configuration without departing from the scope of the present invention.

[0017] Catheters 36 and / or 37 can be inserted percutaneously through the patient's vascular system by a physician 24 into a chamber or vascular structure of heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location in heart 12. One or more catheters, such as 36 and / or 37, can then be inserted into the delivery sheath catheter to reach the desired location in heart 12. For example, system 10 may include a catheter specifically for sensing intracardiac electrogram (IEGM) signals (such as catheter 37), a catheter specifically for ablation (such as catheter 36), a catheter specifically for both sensing and ablation (not specifically shown in the figures), and / or other medical devices. Examples of catheters 37 and 36 are illustrated herein, respectively, which are configured for sensing IEGM and for ablation. Physician 24 can position the distal tip 28 of any catheter 14 so that its multiple medical devices 26 disposed on the flexible / movable section 22 of the catheter 14 can move / bend to approach / contact the heart wall for detecting / treating the target site in heart 12. To sense IEGM signals and / or to ablate tissue, physician 24 may position distal end 28 of respective sensing or ablation catheter 37 or 36 so that its medical device 26 is in proximity to / contact with tissue at the target site.

[0018] The catheters 36 and 37 shown in the figure illustrate medical devices 14 whose positions and / or the positions of at least some of their distal portions 35 (e.g., medical device 26 and / or movable section 22) should be determined (tracked / monitored) by system 10. Magnetic-based position sensors 29 and / or 34 located on the distal tip 28 of the catheters can be operated to provide data indicating the real-time position of the distal portion 35 of the catheters during a medical procedure. The magnetic-based position sensors 29 and 34 operate in conjunction with a locating mat 25, which includes a plurality of locating signal transmitters 32 (e.g., magnetic coils) that generate / transmit electromagnetic locating signals (e.g., magnetic fields) in a predetermined working volume surrounding the patient. The real-time position of the distal tip 28 of the catheters 36 / 37 and / or their distal portions 35 can then be tracked based on the electromagnetic locating signals generated by the locating mat 25 and sensed by the magnetic-based position sensors 29 and / or 34. Details of magnetic-based position sensing technology are described in U.S. Patent Nos. 5,5391,199, 5,443,489, 5,558,091, 6,172,499, 6,239,724, 6,332,089, 6,484,118, 6,618,612, 6,690,963, 6,788,967, and 6,892,091.

[0019] exist Figure 1The catheters 36 and 37 shown in FIG. 1 illustrate medical devices 14 that may be connected to the system 10, and each medical device includes a plurality of distal portions 35, including, in these examples, flexible segments 22 (splines or basket arms) extending from distal tips 28 of the catheters 36 and 37 and a medical instrument 26 disposed thereon. Figure 2 , illustrates a perspective view of an ablation catheter 36 showing an example of a medical device 14 having a movable distal portion 35. The catheter 36 includes a shaft 14H having a distal end / distal tip 28. The catheter 36 in this non-limiting example includes a plurality of distal portions 35 disposed at the distal end / distal tip 28, the distal end / distal tip including a flexible section 22 (hereinafter also referred to as a spline) and a plurality of medical instruments 26 disposed thereon. The splines 22 disposed near / at the distal end 28 form an expandable distal assembly that can be deflected outwardly from the catheter by moving the push rod 14P to engage the medical instruments 26 to approach / contact the tissue wall of the heart in order to ablate a desired area of ​​tissue. In some embodiments, such as within the catheter 37, the medical instrument 26 may include, for example, a near-field intracardiac electrogram sensor / electrode for sensing a near-field signal IEGM signal (e.g., an activated biopotential signal) when the catheter is positioned intracardially and the instrument 26 is proximate to the tissue. In Figure 2 In a non-limiting example, the flexible sections 22 are connected to each other in a "basket"-like formation. In other examples, the flexible sections 22 of the catheter can be connected to each other in different configurations and / or can be independently movable, such as Figure 1 The conduit 37 is shown in FIG, and / or may have a different shape / configuration (eg, other than splines).

[0020] Thus, the system of the present invention can be configured and operable to determine the location of one or more medical devices 14 connected thereto; for example, catheters 36 and / or 37, and / or their distal portions 35. A catheter, such as 36, can include a plurality of position sensors, such as 29 and 34, enabling the system 10 of the present invention to determine the location of the distal portion 35. In this non-limiting example, the catheter 36 includes a position sensor 29 embedded in the body of the catheter (e.g., in or near its distal tip 28) to enable tracking of the position and / or orientation of the distal tip 28 of the catheter 36. Additionally, in this non-limiting example, the catheter 36 includes a plurality of position sensors 34 disposed at its movable section 22 or other distal portion 35, and its position can also be tracked by the system 10. The position sensors 29 and / or 34 are adapted to receive positioning signals transmitted by a positioning signal transmitter / receiver utility of the system 10 and provide the received signals for processing by the system 10. The positioning signals obtained from the position sensors 29 and / or 34 enable the system 10 to determine the respective positions of some or all of the distal portions 35 of the catheter 36, such as the position of the flexible sections 22 thereof and / or the position of the medical devices 26 thereon, and generally the position of the body / distal tip 28 of the catheter 36. In some embodiments, the system 10 may utilize the signals from the position sensors 34 to determine / assess the shape of the distal flexible sections 22 of the catheters while they are bent / displaced during a medical procedure.

[0021] Typically, position sensors 29 and / or 34 are magnetic / electromagnetic based position sensors. In some embodiments, position sensors such as 29 may be implemented as triaxial sensors (TAS) comprising three magnetic coils to enable sensing of their three-dimensional (3D) position and orientation. In some embodiments, position sensors such as 34 may be implemented as single-axis sensors (SAS) comprising one magnetic coil to enable axial sensing of their orientation (e.g., whereby axial position sensing obtained by a SAS sensor may be combined, for example, with three-dimensional (3D) position and orientation sensing of another position sensor of a catheter such as 29 to facilitate determining the positioning of the SAS sensor). It should be noted that Figure 1 The catheter 37 illustrated in FIG. 3 may, in some cases, have a similar construction as the catheter 36 described above, although the flexible sections 22 may be configured differently, eg, not necessarily connected / constrained to each other in a basket formation.

[0022] Back to Figure 1, the system 10 may also include one or more electrode patches 38 that are positioned for skin contact on the patient 23 to establish a positioning reference for the positioning pad 25. Optionally, in some embodiments, one or more of the distal portions 35 include ECG sensors / electrodes, and the positioning pad 25 can also be used to locate such distal portions by impedance-based position tracking. Impedance-based position tracking can be used, for example, to locate distal portions 35 that are not associated / equipped with position sensors capable of sensing their exact positions, provided that the distal portions 35 are provided with electrodes suitable for determining their positions using impedance-based tracking techniques. For impedance-based tracking, current is directed to the electrodes (e.g., ECG electrodes in the case where ECG electrodes are included at / on the distal portion 35). The current is then sensed at the electrode skin patches 38 so that the positioning of each ECG electrode can be triangulated via the electrode patches 38. Details of impedance-based position tracking techniques are described in U.S. Patent Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0023] The system 10 may also include a recorder 11 that records and displays electrograms 21 captured using surface electrocardiogram (ECG) electrodes 18 and intracardiac electrograms (IEGMs) captured using ECG electrodes of one of the medical devices / catheters 14 that may be connected to the system. The recorder 11 may include pacing capabilities for pacing the cardiac rhythm and / or may be electrically connected to a standalone pacemaker.

[0024] The system 10 may include an ablation energy generator 50 adapted to conduct ablation energy to one or more electrodes at the distal tip of one of the catheters 14 configured for ablation. The energy generated by the ablation energy generator 50 may include, but is not limited to, radiofrequency (RF) energy or pulsed field ablation (PFA) energy (including monopolar or bipolar high voltage DC pulses that may be used to achieve irreversible electroporation (IRE)), or a combination thereof.

[0025] The system 10 generally includes a patient interface unit (PIU) 30, which is an interface configured to establish electrical communication between medical devices, such as catheters and / or electrophysiology devices, and a workstation 55 for controlling the operation of the system 10. The medical devices of the system 10 may include, for example, electrophysiology devices, such as one or more catheters 14, positioning pads 25, body surface ECG electrodes 18, electrode patches 38, ablation energy generator 50, and recorder 11. Optionally and preferably, the PIU 30 additionally includes processing capabilities for performing ECG calculations and / or for enabling real-time calculations of the positioning of some of the medical devices / catheters connected to the system.

[0026] The workstation 55 includes a memory, a processor unit having a memory or storage device storing appropriate operating software, and user interface capabilities. The workstation 55 can provide multiple functions, optionally including: (1) three-dimensional (3D) modeling of the endocardial anatomy and rendering the model or anatomical map for display on the display device 27; (2) displaying the activation sequence 20 (or other data) compiled from the recorded electrograms 21 as representative visual markers or images superimposed on the rendered anatomical map on the display device 27; (3) displaying the real-time positioning and orientation of multiple catheters within the heart chamber; and (4) displaying sites of interest on the display device 27, such as where ablation energy has been applied. A commercial product embodying elements of the system 10 can be CARTO TM The 3 system was purchased from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0027] As mentioned above, the PIU 30 typically implements processing capabilities for performing real-time calculations of the positions of some of the medical devices / catheters 14 connected to the system 10. To accomplish this, the PIU 30 typically includes a transmitter-receiver utility (in Figure 1 Not specifically shown in Figure 3A 130 in the PIU 30), the transmitter-receiver utility is capable of transmitting a positioning signal and obtaining a received signal, which is received by a position sensor associated with the medical module in response to the transmission, and applying real-time processing to the received signal to determine data indicating the location of at least some of the medical devices 14 connected to the system 10. Specifically, the transmitter-receiver utility of the PIU 30 includes a signal generator that is connected to the positioning pad 25 and is adapted to generate an electromagnetic positioning signal of a specific plurality of frequencies. The positioning signal is then transmitted by the positioning pad 25 and received by the position sensor 29 and / or 34 of the medical device / module 14 / 26 connected to the system 10.

[0028] The transmitter-receiver utility of the PIU 30 is in turn connected to some of the medical devices 14 and is adapted to collect and process the positioning signals received by their position sensors and determine the phase relative to the transmitted positioning signals, based on which the position of the medical module / device can be determined. The transmitter-receiver utility of the PIU 30 may, for example, be adapted to apply analog-to-digital conversion (sampling) to the positioning signals received from the position sensors of the medical devices connected thereto to determine the phase of the positioning signals relative to the positioning signal transmission thereby performed, and provide / transmit this (or the actual position calculated from the phase) to the workstation 55 for further processing or display to the physician.

[0029] However, in some specific implementations of system 10 (e.g., systems that have been deployed in medical operating facilities), PIU 30 may have limited input channels for collecting and / or simultaneously sampling positioning signals and may not be suitable for accommodating a sufficient number of input channels for multiple position sensors included in an advanced medical device 14 having multiple distal portions 35, the positions of which should be determined separately.

[0030] Thus, in some embodiments, system 10 includes an additional positioning system 100 configured and operable to supplement / expand the functionality of PIU 30 to enable connection to system 10 of additional channels for position sensors for additional medical devices, such as catheters 36 or 37 having one or more respectively movable distal portions 35 at their distal ends 28.

[0031] Now let’s refer to Figure 3A and Figure 3B , which respectively illustrate a block diagram of a positioning system 100 and a flow chart of a method 200 according to an embodiment of the present invention. Figure 3A A configuration of a system 100 is depicted that is suitable for determining the position of a plurality of distal portions 35A through 35K and 35M of one or more medical devices, such as 14A and 14B. Figure 3B The method 200 is illustrated for determining the position of distal portions such as 35A to 35K and 35M. The method 200 is implemented by the system 100, and accordingly, for the sake of brevity, the embodiments of the system 100 and the method 200 of the present invention are hereinafter combined. Figure 3A and Figure 3B Provide a description.

[0032] The system 100 includes a signal processor 102 configured and operable to communicate with Figure 1 The position sensor (for example, 29 and / or 34) is connected to the medical device 14A and / or 14B, and the position sensor is associated with one or more distal parts (such as 35A to 35K, 35M of the medical device 14A and / or 14B), and / or other medical devices or their distal parts, to receive a plurality of positioning signals RS (hereinafter also referred to as received signals) received by the position sensor 29 / 34 associated therewith, and determine the phase of the received positioning signal RS, thereby being able to infer the position of its distal part or part.

[0033] In this non-limiting example, medical modules 35A to 35K, 35M are shown as being associated with / part of medical devices 14A and 14B, respectively. Position sensors of the medical devices 14A and 14B and / or their distal portions 35A to 35K and 35M are connected to the signal processor 102 for use in inferring data indicative of their respective positions by the signal processor 102. It should be understood that the present invention can be implemented using a different number of medical devices and associated distal portions 35 that can be connected to the signal processor 102, and that the specific number of medical devices and distal portions shown in the figures is provided herein as an example and should not be limiting.

[0034] exist Figure 3A , additional medical devices 14C and 14D are illustrated as being connected to a positioning transmitter receiver utility 130 (e.g., Figure 1 30 ), additional medical devices may each have one or more position sensors at their distal ends. Typically, the position transmitter-receiver utility 130, which may or may not be part of the system 100, includes a signal generator 132 that is connectable to a plurality of positioning signal transmitters 32, which are typically disposed in a positioning mat 25 (e.g., a positioning mat 25 intended to be placed near / under a patient being treated to enable positioning of medical devices used in a medical procedure). These signal generators 132 and the transmitter-receiver utility 130 are configured and operable to generate a plurality of positioning transmit signals TR1 to TR2. k (hereinafter referred to as transmit or transmit signal), multiple positioning transmit signals have multiple corresponding transmit frequencies F T(1) to F T(k) (For example, a predetermined frequency). The signal generator 132 transmits the signals TR1 to TR k The positioning signal transmitter 32 is provided to transmit the transmission signal as a wireless electromagnetic signal (eg, magnetic field). In some embodiments, the transmission signal TR1 to TR k are different frequencies F T(1) to F T(k) Continuous wave (CW) signal.

[0035] Then, the transmission signal TR1 to TR k One or more transmitted signals are received / sensed by the position sensors of the medical devices 14A to 14D, and the position of one or more distal portions of the medical devices is determined. The transmitter-receiver utility 130 typically includes a receiver input port / channel R INand a phase processor 135, through which it may be connected to one or more (typically multiple) medical devices, such as medical devices 14C and 14D (i.e., position sensors associated therewith), to obtain positioning signals R received thereby. Positioning signals R received from medical devices 14C and 14D are processed by the transmitter-receiver utility 130 to determine their relative position to corresponding transmitted signals TR1 to TR k The corresponding phase {Δφ} R In this case, the processing is performed by the transmitter-receiver utility 130 and thus relies on the transmitter-receiver utility 130 for generating the transmission signals TR1 to TR k 1. Thus, by using the same clock used for signal transmission, determining the relative phases of the positioning signals R received by the position sensors of the medical devices 14C and 14D connected to the transmitter-receiver utility 130 can be accurately accomplished in a straightforward manner. As will be readily appreciated by those skilled in the art, in this manner, the positions of these medical devices 14C and 14D can be inferred based on the relative phases of the received positioning signals R determined by the transmitter-receiver utility 130.

[0036] However, as mentioned above, the transmitter-receiver utility 130 has a limited number of input ports / channels R IN , and can only obtain and process a limited number of received positioning signals R from a limited number of position sensors of medical devices such as 14C and 14D. With the advent of medical technology and the increase in the number of position sensors such as 29 and 34 equipped at multiple distal portions of medical devices such as 14A and 14B, it is necessary to supplement the signal processing capabilities of the transmitter-receiver utility 130 in order to infer the positions of multiple distal portions 35A to 35K and 35M of such devices (because their number often exceeds the input channels R of the transmitter-receiver utility 130). IN quantity).

[0037] To achieve this, the system 100 includes the aforementioned signal processor 102. The signal processor 102 has an additional input channel / port RS IN, for receiving additional positioning signals RS from position sensors 29 / 34 associated with distal portions, such as 35A to 35K and 35M, of one or more of the medical devices 14A and / or 14B connected to the system 100. In this regard, it should be noted that the phrases received signals and / or positioning signals, designated hereinafter as RS, are used to refer to positioning signals received from position sensors provided at medical devices such as 14A and / or 14B and / or on their distal portions 35A to 35K and 35M, which are connected to the signal processor 102 (in other words, positioning signals RS should be distinguished from positioning signals R of medical devices such as 14C and 14D, which are processed by the transmitter-receiver utility 130). In this context, it should also be noted that the transmitted signals TR1 to TR2 for positioning the medical devices 14A and 14B (e.g., and / or their distal portions 35A to 35K and 35M, whose position sensors are connected to the signal processor 102) k It is generally the same signals TR1 to TR2 that are transmitted by the transmitter-receiver utility 130 and used to locate the medical devices 14C and 14D (whose position sensors are connected to the transmitter-receiver utility 130). k This may be preferred in various implementations of the system, for example for reasons of cost efficiency and in order not to overcrowd the medical operating facility with additional electromagnetic signals and additional equipment for their generation.

[0038] The signal processor 102 is thus configured and operable to process the positioning signal RS received / sensed by the position sensors of the medical devices 14A and 14B to infer information indicative of the position of the medical devices and / or the position of their distal portions. To this end, according to operation 210 of the method 200, the signal processor 102 receives, for example, via an input channel / port RS of the signal processor 102. IN The received positioning signals RS are obtained from the position sensors associated with the distal portions 35A to 35K and 35M of the medical devices 14A and 14B connected thereto. The signal processor 102 then implements operation 220 of the method 200 and processes the positioning signals RS to determine their relative position to the transmitted signals TR1 to TR k The corresponding phase {φ} of the corresponding signal with the same frequency in RS .

[0039] As described above, the frequency of the transmitted signal TR is typically set by the transmitter-receiver utility 130 based on the first clock CLK1, which is the clock of the transmitter-receiver utility 130, while the processing of the received positioning signal RS is performed by the signal processor 102 based on the second clock CLK2, which is the clock of the signal processor 102. The first clock CLK1 and the second clock CLK2 do not have to be synchronized and can typically operate at slightly different respective first and second clock rates and / or have a time lag between them. Therefore, a naive attempt to infer the frequency (and thus also the phase) of the received signal RS based on the clock CLK2 of the signal processor 102 will typically result in a difference between the frequency of the transmitted signal TR and the inferred frequency of the corresponding received signal RS. This, in turn, can result in an erroneous inference of the relative phase between them (e.g., because the inference of the phase depends on the frequency and the time lag / difference between the clocks).

[0040] The signal processor 102 is therefore configured and operable to mitigate such differences in frequency and / or time lags between clocks that may result from a lack of clock synchronization. In some embodiments, the signal processor 102 is configured and operated as follows according to operation 220 of the method 200 to accurately determine the received signals RS relative to their corresponding transmitted signals TR1 to TR k The phase {φ RS The signal processor 102 includes: a clock rate processor 103 adapted to implement operation 220A of the method 200 and determine a clock rate ratio RT between a first rate of the first clock CLK1 of the transmitter-receiver utility 130 and a second rate of the second clock CLK2 of the signal processor 102; a time lag processor 104 adapted to implement operation 220B of the method 200 to determine a time lag ΔT between the first signal clock CLK1 and the second signal clock CLK2 of the transmitter-receiver utility 130 and the signal processor 102, respectively; and a signal synchronizer 105 adapted to implement operation 220C of the method 200 and digitize a received signal RS, wherein the clock rate ratio RT and the time lag ΔT determined by the clock rate processor 103 and the time lag processor 104, respectively, are compensated.

[0041] More specifically, in some embodiments, the clock rate processor 103 is configured and operable to determine a clock rate ratio RT between the first clock rate and the second clock rate by performing the following:

[0042] (a) obtaining a signal indicating at least one received positioning signal (e.g., RS i ) relative to the first clock rate of the first clock CLK1 of the transmitter-receiver utility 130.T(i) The data (i.e., the frequency F T(i) Data, transmit signal TR i (which corresponds to at least one received signal RS i ) is transmitted by the transmitter-receiver utility 130 over the frequency. This generally implements operation 220A-(a) of method 200.

[0043] (b) Processing at least one received positioning signal RS i To determine the receiving frequency F relative to the second clock rate of the second clock CLK2 of the signal processor 102 R(i) - thus generally implementing operation 220A-(b) of method 200; and

[0044] (c) Based on at least one positioning signal RS in (a) and (b) i Inferred emission frequency F T(i)

[0045] and receiving frequency F R(i) To determine the clock rate ratio RT. This generally implements operation 220A-(c) of method 200.

[0046] Operation 220A and its optional sub-operations implemented by the clock rate processor 103 may be performed, for example, based on the following items. For the transmission frequency F obtained in (a) T(i) , the transmitter-receiver utility 130 utilizes a predetermined / preset transmission frequency F T(1) to F T(k) In a typical embodiment for transmitting signals, the clock rate processor 103 may be pre-configured or adjusted to transmit at one of these predetermined / preset transmit frequencies F. T(i) Alternatively, at the transmission frequency F T(1) to F T(k) Instead of being fixed a priori, the clock rate processor 103 may be adapted to obtain data indicative of one or more of them from an external utility such as the transmitter-receiver utility 130 itself or from another utility such as the workstation 55, which data may hold information about the transmit frequency at which the transmitter-receiver utility 130 operates.

[0047] For the received frequency F inferred in (b) R(i) , in various embodiments of the present invention, it is possible to implement a method for receiving a signal RS from i Infer the frequency F R(i) For example, in some embodiments, the clock rate processor 103 digitizes the received signal RS based on the clock rate of the second clock CLK2. i(e.g., samples it), and thereby generates a digitized received signal. The clock rate processor 103 then applies a tone detection process (e.g., spectrum analysis) such as Fourier transform (e.g., FFT) to the digitized signal, and thereby determines the received signal RS relative to the second clock CLK2. i Frequency F R(i) Those skilled in the art will appreciate that in this manner, the received signal RS i The frequency relative to the second clock can be determined by identifying the main peak in the Fourier transform. Alternatively or additionally, in some embodiments, the clock rate processor 103 includes a clock derivation processor (not specifically illustrated in the figure; typically including a comparator and a counter) that is connected to the second clock CLK2 and the input channel / port RS IN , the received signal RS is obtained through the input channel / port i Typically, the clock derivation processor is adapted to determine the received signal RS i The tick count of the second clock CLK2 between the zero crossings and the received signal RS are inferred from this i Relative to the frequency F of the second clock CLK2 rate R(i) (In this implementation, the frequency is determined by clock derivation, and computationally intensive digitization and / or Fourier transformation of the signal may be avoided).

[0048] Finally, the clock rate ratio RT between the first clock of the transmitter-receiver utility 130 and the second clock CLK2 of the signal processor 102 may be determined, for example, according to the received signal RS as determined in (b). i Frequency F R(i) The corresponding transmission frequency F determined as (a) T(i) The ratio between is determined in (c). Because these two frequencies belong to the same underlying signal, but are measured by different respective second clock CLK2 and first clock CLK1, their ratio indicates the ratio RT between the respective rates of the clocks.

[0049] After the clock rate processor 103 determines the clock rate ratio RT, operation 220B and optionally its sub-operations are implemented by the clock rate processor time lag processor 104, as described below. The time lag processor 104 operates to determine the time lag ΔT between the clock CLK1 of the transmitter-receiver utility 130 and the clock CLK2 of the signal processor 102. To achieve this, in some embodiments, the time lag processor 104 is configured and operable to perform the following optional operations:

[0050] (a) Obtaining the clock rate ratio RT determined by the clock rate processor 103 and generating signals TR1 to TR2 having the same value as that transmitted by the transmitter-receiver utility 130 based on the clock rate ratio RT k This generally implements operation 220B-(a) of method 200. In this non-limiting example, a false signal DS having a frequency matching one of the transmission frequencies of the transmission signal TR is generated. j The frequency matches the frequency F T(j) False signal DS.

[0051] (b) The time lag processor 104 then feeds the spurious signal DS to the receiver input Rin of the transmitter-receiver utility 130. As described above, this typically causes the transmitter-receiver utility 130 to determine that the spurious signal DS is the same as the signal transmitted at the same frequency F. T(j) The corresponding transmission signal TR j The phase difference Δφ between DS This generally implements operation 220B of method 200-

[0052] (b).

[0053] (c) After being fed with the dummy signal DS, the time lag processor 104 implements operation 220B-(c) of the method 200. The time lag processor 104 directly or indirectly obtains (e.g., via the workstation 55) the dummy signal DS determined by the transmitter-receiver utility 130 and the corresponding transmit signal TR j The phase difference Δφ between DS , and using the frequency value F of the false signal DS T(j)

[0054] and the phase difference Δφ determined by the transmitter-receiver utility 130 DS To infer the time lag ΔT between the clock CLK1 of the transmitter-receiver utility 130 and the second clock CLK2 of the signal processor 102. The time lag ΔT between the clocks CLK1 and CLK2 can be calculated, for example, as: ΔT=Δφ DS / 2πF T(j) .

[0055] More specifically, in some embodiments, the operation of the time lag processor 104 and operation 220B of the method 200 may be performed, for example, as follows. The time lag processor 104 may include a signal generator 106 connected to the clock CLK2 (i.e., connected to the second clock) of the signal processor 102. In 220B-(a), the time lag processor 104 may operate the signal generator 106 to generate a desired transmission frequency F T(j)In this regard, it should be understood that the frequency of the dummy signal should match one of the transmit frequencies of the transmitter receiver utility 130, for example, the frequency F T(j) Therefore, since the frequency F T(j) In order to generate the dummy signal DS of the frequency based on the second clock CLK2 of the signal processor relative to the clock CLK1 of the transmitter-receiver utility 130, the time lag processor 104 performs clock rate compensation to compensate for the difference between the clock rate of the second clock CLK2 used to generate the dummy signal DS and the clock rate of the first clock CLK1 of the transmitter-receiver utility 130. The clock rate compensation is based on the clock rate ratio RT between the first clock CLK1 and the second clock CLK2 determined by the clock rate processor 103, and in various embodiments of the present invention, can be achieved, for example, by any one of the following techniques or a combination thereof: (i) by adjusting the rate of the second clock CLK2 by a factor of the clock rate ratio RS so that it matches the rate of the first clock CLK1; and / or (ii) by utilizing the second clock CLK2 (e.g., without adjusting its rate) but by generating a dummy signal having a frequency F T(j) The compensation is applied by multiplying the spurious signal DS by the clock rate ratio RS. Thus, a signal having a frequency F set relative to the first clock CLK1 of the transmitter receiver utility 130 is generated. T(j) , so that when it is processed by the transmitter receiver utility 130 based on the first clock CLK1, the transmitter receiver utility 130 "identifies" it as having a frequency F that matches one of its transmission signals. T(j) , and their relative phases will be determined accordingly.

[0056] In some implementations, the system 100 includes a signal channel 107 (e.g., a signal cable / communication path) having a substantially fixed and predetermined latency Δt, adapted to interconnect the time lag processor 104 directly or indirectly (e.g., via the workstation 55) to an input channel R of the transmitter receiver utility 130. IN In such an embodiment, the time lag processor 104 is adapted to feed the dummy signal DS as input to the transmitter receiver utility 130 via a signal channel 107 having a substantially fixed latency. Then, the phase difference Δφ of the dummy signal DS is received and processed. DS To determine the time lag ΔT, the time lag processor 104 counts the fixed predetermined waiting time Δt of the signal channel 107 (e.g., and subtracts the waiting time from the calculated time lag ΔT to thereby obtain ΔT more precisely as: ΔT=Δφ DS / 2πF T(j) -Δt).

[0057] Following the operations of the clock rate processor 103 and the time lag processor 104, the signal synchronizer 105 implements operation 220C of the method 200 to determine the received positioning signal RS relative to the corresponding transmissions TR1 to TR1 of the positioning signal performed by the transmitter receiver utility 130. k Phase Δφ RS , so that the position of the medical module connected to the signal processor 102 can be based on these phases Δφ RS The signal synchronizer 105 processes the received positioning signal RS based on the second clock CLK2, the clock rate ratio RT determined by the clock rate processor 103 and the time lag ΔT determined by the time lag processor 104 to determine the phase Δφ of the received signal RS. RS .

[0058] For example, in some embodiments, the signal synchronizer 105 digitizes the received positioning signal RS using the second clock CLK2 and compensates for the difference in clock rate RT and the time lag ΔT between the clocks CLK1 and CLK2 using the clock rate ratio RT and the time lag ΔT. Thus, in such embodiments, the signal synchronizer 105 generates corresponding digitized received signals whose frequencies and phases are adjusted relative to the first signal clock CLK1 of the transmitter receiver utility 130. Then, once the frequencies and phases of the received signals (or digitized versions thereof) are adjusted relative to the first signal clock CLK1, the signal processor 102 or the signal synchronizer 105 can process these signals (e.g., using tone detection (e.g., FFT) or clock derivation, as described above) to determine the phases {Δφ} of these signals relative to the corresponding transmit signals transmitted by the transmitter receiver utility 130. RS .

[0059] To achieve this, in some implementations, the signal synchronizer 105 is adapted to compensate for the clock rate difference by adjusting the rate of the second clock CLK2 so as to reduce or eliminate the difference between its rate (the second rate) and the rate of the first clock CLK1 of the transmitter-receiver utility 130. The rate of the second clock CLK2 can be adjusted, for example, by a factor of the clock rate ratio RS so that it matches the rate of the first clock CLK1. Alternatively or additionally, the signal synchronizer 105 can be adapted to digitize the received signal RS based on the second clock CLK2 (e.g., without requiring clock rate adjustment) and then compensate for the clock rate difference RT by interpolating the digitized signal based on the clock rate ratio RS (e.g., "interpolation" in this context can in some cases be achieved simply by adjusting the time tags of the signal samples by a factor of the clock rate ratio RS, which is a lightly weighted computation process, or by interpolating the samples themselves). Thus, in any of these illustrated techniques, the received signal RS is obtained as an interpolated digital signal whose sampling interval (and therefore frequency) corresponds to the first clock rate of the first clock of the transmitter-receiver utility 130.

[0060] Furthermore, the signal synchronizer 105 may be adapted, for example, to compensate for the time lag ΔT between the first clock CLK1 and the second clock CLK2 by adjusting the phase / timing of the second clock CLK2 so as to reduce or eliminate the time lag ΔT. Alternatively or additionally, compensation for the time lag ΔT may be performed by interpolating the digitized signal to shift its samples (or sample labels) according to the time lag ΔT, thereby generating a digitized signal as an interpolated digital signal in which the samples are time-shifted (and thus phase-adjusted) relative to the timing of the first clock CLK1 of the transmitter-receiver utility 130.

[0061] To this end, the phase {Δφ} of the received positioning signal RS (determined by the signal processor 102 relative to the corresponding transmission of the positioning signal by the transmitter-receiver utility 130 according to the above-described technique) RS Suitable for further processing to determine the position of the position sensors 29 and / or 34 of the medical devices 14A and 14B and their associated distal portions 35A to 35K and 35M (which are connected to the signal processor 102).

[0062] In some embodiments, the system 100 further implements operation 230 of the optional method 200 and optionally includes a positioning utility 109 configured and operable to determine the positions of the position sensors 29 and / or 34 of the medical devices 14A and 14B and their respective distal portions 35A to 35K and 35M (based on the phase {Δφ} of their received signals RS inferred by the signal processor 102). RS). The positioning utility 109 may be part of the signal processor 102 or part of the workstation 55 connected to the signal processor 102 for receiving the phase {Δφ} RS In some embodiments, the positioning utility 109 may be adapted to also process the phase {Δφ} of the received signal R received / sensed by the position sensor of the medical device 14C and / or 14D. R , as described above, the phase is inferred by the transmitter-receiver utility 130. To this end, the positioning utility 109 can be used to determine the positions of all position sensors 29 and / or 34 of medical devices connected to the system, regardless of whether the relative phases of the positioning signals R / RS sensed thereby are determined by the transmitter-receiver utility 130 or by the signal processor 102 of the present invention.

[0063] As will be readily appreciated by those skilled in the art, position determination relative to the respective positions of the signal transmitters, such as 32, can itself be accomplished by various techniques known in the art (so long as the phase is correctly measured relative to the corresponding transmitted signals), such as utilizing time of arrival (TOA), difference time of arrival (DTOA), triangulation, and / or any other suitable technique or combination thereof to determine the position and / or orientation of the medical module relative to the reference frame (coordinates) defined by the signal transmitters, such as 32. The positioning utility 109 is thus configured and operable to accordingly determine the position of the position sensors 29 and / or 34 and the medical devices connected to the system 10. Thus, the positions of the medical devices 14A and 14B and / or their distal portions, such as 35A to 35K and / or 35M, can be determined by the system 100.

[0064] In this regard, returning to Figure 1 and Figure 2 As described above, in some implementations, the medical device 14 may be configured with a position sensor 29 disposed on its body (e.g., the shaft of a catheter), while one or more additional position sensors 34 may be provided on other distal portions 35 of the medical device 14, such as on the flexible section 22 of the medical device, and / or on a medical instrument 26 located thereon. In some implementations, one or more of the position sensors 29 and / or 34 may be implemented as single-axis sensors (SAS) and may be utilized by the system to determine the orientation of the distal portion to which they are provided. In some implementations, one or more of the position sensors 29 and / or 34 may be implemented as three-axis sensors (TAS), which may be used to measure the position and orientation of the distal portion to which they are provided. Thus, as described above, the phrase position as used herein should be understood to refer to either the position, orientation, or both of the distal portion 35 of the medical device 14.

[0065] To this end, it should be noted that in some implementations, a medical device connected to the system may include at least one position sensor, a triaxial sensor (TAS), such as 29, and one or more single-axis position sensors (SAS), such as 34, disposed at a distal portion thereof. In such a case, the position of the one or more single-axis position sensors (SAS) 34 on the distal portion may be determined by a positioning utility based on the inferred position and orientation of the triaxial sensor (TAS), such as 29, the inferred orientation of the one or more single-axis position sensors (SAS) 34, and a priori data indicating a configuration / shape that the medical device may acquire / conform to during a medical procedure.

[0066] Example

[0067] Example 1. A method 200 for determining the position of one or more portions 35 of the distal end 28 of a catheter 14, the method comprising:

[0068] A plurality of positioning signals RS are received by the position sensors 29 and / or 34 at at least a portion 35 of the distal end 28 of the catheter, the plurality of positioning signals being transmitted by the transmitter-receiver utility 130 at a respective plurality of transmission frequencies F relative to a first clock rate CLK1 associated with the transmitter-receiver utility 130. T(1) to F T(k) The transmitted wireless electromagnetic signals TR1 to TR k ;as well as

[0069] The positioning signal RS is processed (220) by a signal processor 102 associated with a second signal clock CLK2 asynchronous with the first clock CLK1 and having a second clock rate to determine the positioning signal RS relative to the corresponding transmissions TR1 to TR1 of the positioning signal by the transmitter-receiver utility 130. k Phase {Δφ} RS , the processing includes:

[0070] A. determining (220A) a clock rate ratio RT as a ratio between the rates of the first clock CLK1 and the second clock CLK2;

[0071] B. Determining (220B) a time lag ΔT between the first signal clock CLK1 and the second signal clock CLK2; and

[0072] C. Digitizing the positioning signal RS based on the second clock CLK2 to generate a corresponding digitized signal. The digitization includes (220C) compensating for the clock rate ratio RT and compensating for the time lag ΔT so that the frequency and phase of the digitized signal are adjusted relative to the first signal clock CLK1 of the transmitter-receiver utility 130.

[0073] The positioning signal RS is thus determined relative to the corresponding transmissions TR1 to TR of the positioning signal made by the transmitter-receiver utility 130. k The phase {Δφ} RS , and enabling the phase {Δφ} to be determined based on RS The position of the at least portion 35 of the distal end 28 of the catheter 14 is determined.

[0074] Embodiment 2. The method of embodiment 1, wherein the determining of the clock rate ratio between the first clock rate and the second clock rate comprises:

[0075] (a) providing data indicating a transmission frequency of at least one of the positioning signals relative to the first clock rate of the transmitter-receiver utility (the positioning signal being transmitted based on the transmitter-receiver utility);

[0076] (b) processing, by the signal processor, the at least one positioning signal and determining a received frequency of the at least one positioning signal relative to the second clock rate; and

[0077] (c) Determining the clock rate ratio based on the transmit frequency and the receive frequency.

[0078] Example 3. A method according to Example 2, wherein the determination of the received frequency of the at least one positioning signal relative to the second clock rate includes: digitizing the positioning signal based on the second clock to produce a digitized signal, and applying tone detection processing such as FFT to the digitized signal.

[0079] Embodiment 4. The method of embodiment 2 or 3, wherein the determining of the reception frequency of the at least one positioning signal relative to the second clock rate comprises applying a clock derivation process to the at least one positioning signal.

[0080] Example 5. A method according to Example 4, wherein the clock derivation processing includes: determining the tick count of the second signal clock between the zero crossing points of the at least one positioning signal, and thereby determining the received frequency of the at least one positioning signal relative to the second signal clock.

[0081] Embodiment 6. The method of any one of embodiments 1 to 5, wherein the determining of the time lag between the first signal clock and the second signal clock comprises:

[0082] (a) utilizing the clock rate ratio for the signal processor to generate a dummy signal having a frequency matching a particular one of the transmission frequencies of the positioning signal, and feeding the dummy signal to a receiver input of the transmitter-receiver utility to thereby cause the transmitter-receiver utility to determine a phase difference between the dummy signal and one of the wireless electromagnetic signals transmitted thereby at the particular transmission frequency; and

[0083] (b) determining the time lag between the clocks based on the phase difference and the specific transmission frequency.

[0084] Embodiment 7. The method of embodiment 6, wherein the feeding of the dummy signal is performed using a channel having a substantially fixed latency, and wherein the fixed latency is taken into account in the determination of the time lag.

[0085] Embodiment 8. The method of embodiment 6 or 7, wherein the generating of the dummy signal comprises compensating the clock rate ratio to thereby obtain the dummy signal having a frequency matching the specific transmit frequency.

[0086] Embodiment 9. The method according to any one of embodiments 6 to 8, comprising:

[0087] The phase difference between the spurious signal and the one of the wireless electromagnetic signals is provided to the signal processor for use in the determination of the time lag.

[0088] Embodiment 10. A method according to any one of embodiments 1 to 9, wherein compensating for the clock rate ratio includes: adjusting the second clock rate of the second signal clock so as to reduce or eliminate the difference between the first clock rate and the second clock rate.

[0089] Embodiment 11. The method according to any one of embodiments 1 to 10, wherein compensating for the time lag comprises adjusting the phase of the second signal clock so as to reduce or eliminate the time lag.

[0090] Example 12. A method according to any one of Examples 1 to 11, wherein compensating for the clock rate ratio includes: re-interpolating the digitized signal based on the clock rate ratio to generate the digitized signal having samples corresponding to the sampling rate of the first signal clock.

[0091] Example 13. A method according to any one of Examples 1 to 12, wherein compensating for the time lag includes: re-interpolating the digitized signal according to the time lag to shift the phase of the digitized signal, and thereby generating the digitized signal, the digitized signal having a phase adjusted relative to a corresponding transmission of the digitized signal by a transmitter-receiver utility.

[0092] Example 14. A method according to any one of Examples 1 to 13, the method further comprising determining the position of at least a portion of the distal end of the catheter based on the phase of the received positioning signal, whereby the position indicates at least one of the position and orientation of the at least a portion of the distal end of the catheter relative to one or more reference frame coordinates.

[0093] Example 15. A system 100 for determining the position of one or more portions 35 of a distal end 28 of a catheter 14, the system comprising:

[0094] a signal processor 102 configured and operable to be connected to a position sensor 29 and / or 34 disposed at at least a portion 35 of the distal end 28 of the catheter 14 for receiving from the position sensor 29 and / or 34 a signal indicating a plurality of transmission frequencies F transmitted by the transmitter-receiver utility 130 at a first clock rate relative to a first clock CLK1 of the transmitter-receiver utility 130; T(1) to F T(k) The electromagnetic signals TR1 to TR1 transmitted and received by the position sensors 29 and / or 34 are k Multiple positioning signals RS;

[0095] The signal processor 102 includes a second signal clock CLK2 having a second clock rate that is asynchronous with the first clock CLK1. The signal processor 102 is configured and operable to process the positioning signal RS to determine the positioning signal relative to the corresponding transmissions TR1 to TR1 of the positioning signal by the transmitter-receiver utility 130. k Phase {Δφ} RS .

[0096] The signal processor 102 includes:

[0097] A. a clock rate processor 103 adapted to determine a clock rate ratio RT between the clock rates of the first clock CLK1 and the second clock CLK2;

[0098] B. a time lag processor 104 adapted to determine a time lag ΔT between the first clock CLK1 and the second clock CLK2 ; and

[0099] C. A signal synchronizer 105 configured and operable to utilize the second clock CLK2, the clock rate ratio RT

[0100] and the time lag ΔT to digitize the positioning signal RS and compensate for the clock rate ratio RT and the time lag ΔT

[0101] Compensation is performed to thereby generate a corresponding digitized signal having a frequency and phase adjusted relative to the first signal clock CLK1 of the transmitter-receiver utility 130 .

[0102] The signal processor thus determines the positioning signal RS relative to the corresponding transmissions TR1 to TR of the positioning signal made by the transmitter-receiver utility 130 k The phase {Δφ} RS , and enabling the phase {Δφ} to be determined based on RS The position of the at least portion 35 of the distal end 28 of the catheter 14 is determined.

[0103] Embodiment 16. The system of embodiment 15, wherein the clock rate processor is configured and operable to determine the clock rate ratio by performing the following:

[0104] (a) obtaining data indicative of a transmission frequency of at least one of the positioning signals relative to the first clock rate of the transmitter-receiver utility;

[0105] (b) processing the at least one positioning signal to determine a received frequency of the at least one positioning signal relative to the second clock rate; and

[0106] (c) determining the clock rate ratio based on the transmit frequency and the receive frequency of the at least one positioning signal.

[0107] Example 17. A system according to Example 16, wherein the clock rate processor is suitable for determining the received frequency of the at least one positioning signal relative to the second clock rate by digitizing the positioning signal based on the clock rate of the second clock to produce a digitized signal, and applying tone detection processing to the digitized signal to thereby determine the frequency of the positioning signal.

[0108] Embodiment 18. The system of embodiment 16 or 17, wherein the clock rate processor comprises a clock derivation processor adapted to determine the received frequency of the at least one positioning signal relative to the second clock rate. The clock derivation processor is configured and operable to determine a tick count of the second signal clock between zero crossings of the at least one positioning signal and thereby determine the received frequency of the at least one positioning signal relative to the second signal clock.

[0109] Embodiment 19. The system of any one of embodiments 15 to 18, wherein the time lag processor is configured and operable to determine the time lag by performing the following:

[0110] (a) obtaining the clock rate ratio from the clock rate processor, and generating a dummy signal having a frequency matching a specific one of the transmit frequencies using the clock rate ratio;

[0111] (b) feeding the dummy signal to a receiver input of the transmitter-receiver utility to thereby cause the transmitter-receiver utility to determine a phase difference between the dummy signal and one of the wireless electromagnetic signals transmitted by the transmitter-receiver utility at the particular transmit frequency; and

[0112] (c) obtaining the phase difference and determining the time lag based on the phase difference and the specific transmission frequency.

[0113] Embodiment 20. The system of embodiment 19, further comprising a signal channel having a substantially fixed and predetermined latency interconnected directly or indirectly between the signal processor and the transmitter-receiver utility. The time lag processor may be adapted to feed the pseudo CW signal to the transmitter-receiver utility via the channel having the substantially fixed latency, and to take the fixed latency of the channel into account when determining the time lag.

[0114] Embodiment 21. The system of embodiment 19 or 20, wherein the time lag processor is adapted to perform the compensation for the clock rate ratio when generating the dummy signal such that the dummy signal is generated at a frequency that matches the specific transmit frequency.

[0115] Embodiment 22. The system of any one of embodiments 19 to 21, comprising a direct or indirect connection to the transmitter-receiver utility, the time lag processor being adapted to utilize the connection to obtain the phase difference between the spurious signal and the one of the wireless electromagnetic signals transmitted by the transmitter-receiver utility at a frequency similar to the frequency of the spurious signal, and thereby determine the time lag.

[0116] Embodiment 23. A system according to any one of Embodiments 15 to 22, wherein the signal synchronizer is configured and operable to perform the compensation of the clock rate ratio by adjusting the second clock rate of the second signal clock so as to reduce or eliminate the difference between the second clock rate and the first clock rate of the first clock of the transmitter receiver utility.

[0117] Embodiment 24. A system according to any one of embodiments 15 to 23, wherein the signal synchronizer is configured and operable to perform the compensation for the clock rate ratio by interpolating the digitized signal according to the clock rate ratio to produce the digitized signal as an interpolated digital signal having samples of the first clock rate corresponding to the first clock of the transmitter receiver utility.

[0118] Embodiment 25. A system according to any one of Embodiments 15 to 24, wherein the signal synchronizer is configured and operable to perform the compensation for the time lag by adjusting the phase of the second clock so as to reduce or eliminate the time lag between the first clock and the second clock.

[0119] Embodiment 26. A system according to any one of embodiments 15 to 25, wherein the signal synchronizer is configured and operable to perform the compensation for the time lag by interpolating the digitized signal according to the time lag to shift the phase of the digitized signal, and thereby generate the digitized signal as an interpolated digital signal having a phase adjusted relative to the timing of the first clock of the transmitter receiver utility.

[0120] Example 27. A system according to any one of Examples 15 to 26, wherein the system further comprises a position determination utility configured and operable to determine the position of at least a portion of the distal end of the catheter based on the phase; and wherein the position comprises at least one of a location and an orientation of the at least a portion of the distal end of the catheter relative to one or more reference frame coordinates.

[0121] It should be understood that the above embodiments are cited by way of example, and the present disclosure is not limited to what is specifically shown and described above. On the contrary, the scope of the present disclosure includes combinations and subcombinations of the various features described above, as well as variations and modifications thereof, which will occur to those skilled in the art upon reading the description of the present invention and which are not disclosed in the prior art.

Claims

1. A method (200) of determining a position of at least a portion (35) of a distal end (28) of a catheter (14), The method includes receiving a plurality of positioning signals (RS) by a position sensor (29, 34) at the at least a portion (35) of the distal end (28) of the catheter, wherein the plurality of positioning signals (RS) are transmitted by a transmitter-receiver utility (130) at a respective plurality of transmission frequencies (F) relative to a first clock rate (CLK1) associated with the transmitter-receiver utility (130). T(1) To F T(k) ) transmits wireless electromagnetic signals (TR1 to TR k ); It is characterized in that The method comprises processing (220) the positioning signal (RS) by a signal processor (102) associated with a second signal clock (CLK2) that is asynchronous with respect to the first clock (CLK1) and has a second clock rate to determine the positioning signal (RS) relative to a corresponding transmission (TR1 to TR2) of the positioning signal by the transmitter-receiver utility (130). k )'s phase ({Δφ} RS ), wherein the processing (220) comprises: A. determining (220A) a clock rate ratio (RT) as a ratio between the first clock rate and the second clock rate; B. Determining (220B) a time lag (ΔT) between the first signal clock (CLK1) and the second signal clock (CLK2); and C. digitizing the positioning signal (RS) based on the second clock (CLK2) to produce a corresponding digitized signal, wherein the digitizing includes compensating (220C) the clock rate ratio (RT) and compensating the time lag (ΔT) so that the frequency and phase of the digitized signal are adjusted relative to the first signal clock (CLK1) of the transmitter receiver utility (130); The positioning signal (RS) is thereby determined relative to the corresponding transmission (TR1 to TR2) of the positioning signal by the transmitter-receiver utility (130). k ) of the phase ({Δφ} RS ), and enables the phase ({Δφ} RS ) determines the position of at least a portion (35) of the distal end (28) of the catheter.

2. The method according to claim 1, wherein: The determination of the clock rate ratio (RT) between the first clock rate and the second clock rate comprises: (a) providing data indicative of a transmission frequency of at least one of said positioning signals relative to said first clock rate of said transmitter-receiver utility (130) transmitting said at least one positioning signal; as well as (b) processing the at least one positioning signal by the signal processor (102), and determining a reception frequency of the at least one positioning signal relative to the second clock rate; as well as The clock rate ratio (RT) is thereby determined based on the transmit frequency and the receive frequency.

3. The method according to claim 2, wherein: The determination of the reception frequency of the at least one positioning signal relative to the second clock rate comprises at least one of: - digitizing the positioning signal based on the second clock (CLK2) to produce a digitized signal, and applying a tone detection process to the digitized signal; as well as -Applying clock derivation processing to the at least one positioning signal; wherein the clock derivation processing includes: determining the tick count of the second signal clock (CLK2) between the zero crossing points of the at least one positioning signal, and thereby determining the reception frequency of the at least one positioning signal relative to the second signal clock (CLK2).

4. The method according to any one of claims 1 to 3, wherein: The determination of the time lag (ΔT) between the first signal clock and the second signal clock comprises the following: (a) using the clock rate ratio (RT) to generate a clock signal having a frequency which is the same as the transmission frequency (F T(1) To F T(k) ) in the specific transmission frequency (F T(j) ) and feeding the false signal (DS) to the receiver input of the transmitter-receiver utility, so that the transmitter-receiver utility determines the false signal (DS) and the transmission frequency (F) T(j) ) transmitted by the wireless electromagnetic signal (TR1 to TR k ) between a wireless electromagnetic signal (Δφ DS ); as well as (b) Based on the phase difference (Δφ DS ) and the specific transmission frequency (F T(j) ) determines the time lag (ΔT).

5. The method according to claim 4, wherein: At least one of the following: - said feeding of said dummy signal (DS) is performed using a channel (107) having a substantially fixed latency, and wherein said fixed latency is taken into account in said determination of said time lag (ΔT); - said generation of said false signal (DS) comprises: compensating said clock rate ratio (RT) to thereby obtain a clock signal having a frequency corresponding to said specific transmission frequency (F T(j) ) of the false signal (DS) of a frequency matching; and - the method further comprises: combining the false signal (DS) with the wireless electromagnetic signal (TR1 to TR k ) between the one wireless electromagnetic signal (Δφ DS ) is provided to the signal processor (102) for use in the time delay (ΔT) is determined.

6. The method according to any one of claims 1 to 5, wherein: The compensating the clock rate ratio (RT) comprises at least one of the following: - adjusting a second clock rate of the second signal clock (CLK2) so as to reduce or eliminate a difference between the first clock rate and the second clock rate; as well as - re-interpolating the digitized signal based on the clock rate ratio (RT) to produce the digitized signal having samples corresponding to a sampling rate of the first signal clock (CLK1).

7. The method according to any one of claims 1 to 6, wherein: The compensating the time lag (ΔT) comprises at least one of the following: - adjusting the phase of the second signal clock (CLK2) so as to reduce or eliminate the time lag (ΔT); as well as - re-interpolating the digitized signal according to the time lag (ΔT) to shift the phase of the digitized signal and thereby generate the digitized signal having a phase adjusted relative to a corresponding transmission of the digitized signal by the transmitter-receiver utility (130).

8. A system (100) for determining a position of at least a portion (35) of a distal end (28) of a catheter (14), the system comprising: A signal processor (102) configured and operable to be connected to a position sensor (29, 34) disposed at at least a portion (35) of a distal end (28) of a catheter (14) for receiving from the position sensor (29 or 34) a signal indicating a plurality of transmission frequencies (F) transmitted by a transmitter-receiver utility (130) at a first clock rate relative to a first clock (CLK1) of the transmitter-receiver utility (130) T(1) To F T(k) ) and received by the position sensor (29 or 34) k ) of multiple positioning signals (RS); The invention is characterized in that the signal processor (102) includes a second signal clock (CLK2) having a second clock rate that is asynchronous with the first clock (CLK1); and wherein the signal processor (102) is configured and operable to process the positioning signal (RS) to determine the positioning signal relative to a corresponding transmission (TR1 to TR1) of the positioning signal by the transmitter-receiver utility (130). k )'s phase ({Δφ} RS ); the signal processor (102) comprises: A. a clock rate processor (103) adapted to determine a clock rate ratio (RT) between the first clock rate and the second clock rate; B. a time lag processor (104) adapted to determine a time lag (ΔT) between the first signal clock (CLK1) and the second signal clock (CLK2); and C. a signal synchronizer (105) configured and operable to digitize the positioning signal (RS) using the second clock (CLK2), the clock rate ratio (RT) and the time lag (ΔT) and to compensate for the clock rate ratio (RT) and to compensate for the time lag (ΔT) to generate a corresponding digitized signal having a frequency and phase adjusted relative to the first signal clock (CLK1) of the transmitter receiver utility (130); The signal processor (102) thereby determines the positioning signal (RS) relative to the corresponding transmission (TR1 to TR2) of the positioning signal by the transmitter receiver utility (130). k ) of the phase ({Δφ} RS ), and thereby enable the phase ({Δφ} RS ) determines the position of at least a portion (35) of the distal end (28) of the catheter (14).

9. The system according to claim 8, wherein: The clock rate processor (103) is configured and operable to determine the clock rate ratio (RT) by performing the following: (a) obtaining data indicative of a transmission frequency of at least one of said positioning signals (RS) relative to said first clock rate of said transmitter-receiver utility (130); (b) processing the at least one positioning signal to determine a received frequency of the at least one positioning signal relative to the second clock rate; as well as (c) determining the clock rate ratio (RT) based on the transmission frequency and the reception frequency of the at least one positioning signal.

10. The system according to claim 9, wherein: At least one of the following: - the clock rate processor (103) is adapted to determine the received frequency of the at least one locating signal relative to the second clock rate by digitizing the locating signal based on the clock rate of the second clock to produce a digitized signal, and applying a tone detection process to the digitized signal to thereby determine the frequency of the locating signal; as well as -The clock rate processor (103) includes a clock derivation processor, which is suitable for determining the received frequency of the at least one positioning signal relative to the second clock rate; and wherein the clock derivation processor is configured and capable of operating to determine the tick count of the second signal clock (CLK2) between zero crossings of the at least one positioning signal, and thereby determine the received frequency of the at least one positioning signal relative to the second signal clock.

11. A system according to any one of claims 8 to 10, wherein: The time lag processor (104) is configured and operable to determine the time lag (ΔT) by performing the following: (a) obtaining the clock rate ratio (RT) from the clock rate processor (103), and generating a clock signal having the same frequency as the transmission frequency (F) by using the clock rate ratio (RT); T(1) To F T(k) ) in the specific transmission frequency (F T(j) ) and feeding the false signal (DS) to the receiver input (Rin) of the transmitter-receiver utility (130) so that the transmitter-receiver utility (130) determines the false signal (DS) and the transmission frequency (F) T(j) ) transmitted by the wireless electromagnetic signal (TR1 to TR k ) between a wireless electromagnetic signal (Δφ DS ); as well as (b) Obtain the phase difference (Δφ DS ) and based on the phase difference (Δφ DS ) and the specific transmission frequency (F T(j) ) determines the time lag (ΔT).

12. The system according to claim 11, wherein: At least one of the following: - the system (100) comprises a signal channel (107) with a substantially fixed and predetermined latency interconnected directly or indirectly between the signal processor (102) and the transmitter-receiver utility (103), and wherein the time lag processor (104) is adapted to feed the dummy signal (DS) to the transmitter-receiver utility (130) via the channel (107) with the substantially fixed latency and to take into account the fixed latency of the channel when determining the time lag (ΔT); - the time lag processor (104) is adapted to perform the compensation of the clock rate ratio (RT) when generating the dummy signal (DS) so that the dummy signal (DS) is transmitted at a frequency which is consistent with the specific transmission frequency (F T(j) ) matching frequency generation; and - the system (100) comprises a direct or indirect connection with the transmitter-receiver utility (130), and wherein the time lag processor (104) is adapted to utilize the connection to obtain the phase difference (Δφ) between the false signal (DS) and the one of the wireless electromagnetic signals transmitted by the transmitter-receiver utility (130) at a frequency similar to the frequency of the false signal (DS) DS ), and thereby enables the time lag (ΔT) to be determined.

13. A system according to any one of claims 8 to 12, wherein: The signal synchronizer (105) is configured and operable to perform the compensation of the clock rate ratio (RT) by at least one of: - adjusting the second clock rate of the second signal clock (CLK2) so as to reduce or eliminate a difference between the second clock rate and the first clock rate of the first clock (CLK1) of the transmitter receiver utility (130); as well as - interpolating the digitized signal according to the clock rate ratio (RT) to produce the digitized signal as an interpolated digital signal of samples having the first clock rate corresponding to the first clock (CLK1) of the transmitter receiver utility (130).

14. A system according to any one of claims 8 to 13, wherein: The signal synchronizer is configured and operable to perform the compensation for the time lag by at least one of: - adjusting the phase of the second clock (CLK2) so as to reduce or eliminate the time lag (ΔT) between the first clock (CLK1) and the second clock (CLK2); as well as - interpolating the digitized signal to shift the phase of the digitized signal according to the time lag (ΔT) and thereby generating the digitized signal as an interpolated digital signal having a phase adjusted relative to the timing of the first clock (CLK1) of the transmitter receiver utility (130).

15. The system according to any one of claims 8 to 14, further comprising a position determination utility (109) configured and operable to determine the position of the at least a portion (35) of the distal end (28) of the catheter (14) based on the phase; and wherein, The position includes at least one of a location and an orientation of the at least a portion (35) of the distal end (28) of the catheter relative to one or more reference frame coordinates.

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