Smart port splitter for multiple medical instruments

Abstract

To track a medical probe in vivo.SOLUTION: An apparatus includes input channels, output channels, a control channel, and switching circuitry. The input channels receive position signals from multiple medical instruments located in an organ of a patient. The output channels forward one or more of the position signals to a position tracking system. The control channel receives control signals from the position tracking system. The switching circuitry forwards at least some of the position signals to the output channels in accordance with a first switching scheme, receives from the position tracking system, over the control channel, in response to the forwarded position signals, a control signal indicative of a given medical instrument that was identified as being located within a working volume of the position tracking system, and switches to a second switching scheme, in which all the position signals of the given medical instrument are forwarded to at least some of the output channels.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure generally relates to medical probes, and more particularly to in vivo tracking of medical probes.

Background Art

[0002] Techniques for guiding invasive probes within the lumen of organs to target tissue have been previously proposed in the patent literature. For example, U.S. Patent Application Publication No. 2019 / 0090959 describes improvements related to computer-aided surgery (CAS) using an on-board tool tracking (OTT) system. Some of the improvements relate to methods of providing feedback during a procedure to improve the efficiency or quality, or both, of the procedure, including the speed and type of data processed according to the CAS mode. In an example, to provide navigation assistance during an OTT CAS procedure, the OTT device monitors the position of relevant surgical tools within the surgical field. The OTT CAS system may not use one or more coordinate systems, including one or more position sensors or one or more fiducial markers, depending on the requirements of the OTT CAS procedure performed.

[0003] As another example, U.S. Patent Application Publication No. 2016 / 0183841 describes a method of guiding an intervention device within a patient's anatomical structure, including processing a target position within the patient's anatomical structure and receiving the position of the distal tip portion of the intervention device at a first position within the patient's anatomical structure. The method further includes determining a three-dimensional distance between the first position and the target position and displaying a symbol representing the target position and a symbol representing the distal tip portion of the intervention device. In an example, the rotational orientation of the mechanism of the distal tip portion may further be displayed with a rotational assist symbol in a navigation assistance image. For example, when a biopsy device has a lateral opening, the side with the opening may be indicated with a rotational assist symbol in the navigation assistance image.

[0004] U.S. Patent No. 11,065,061 describes devices, systems, and methods for performing image-guided interventions and surgical procedures, including various procedures for treating sinusitis and other disorders of the sinuses, ears, nose, or throat. In some applications, preoperative tomographic scans (e.g., CT scans) may be acquired, and the image-guided system may be programmed to display the tomographic images on a video monitor, along with real-time indications (e.g., crosshairs, illuminated dots, etc.) of the position of the working device relative to the anatomical structures shown in the tomographic images.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0006] Abstract The distal end portion of a probe, such as an otolaryngology (ENT) probe used in a guidance system, can be tracked to be visually used as a position cursor (i.e., pointer) in a 3D view of a patient's cavity (e.g., a medical image). For example, an ENT suction tool or shaver can be used in this way with a TruDi™ ENT tracking system (manufactured by Acclarent, Irvine, California). The medical image can be generated, for example, from images of computerized tomography (CT) and magnetic resonance imaging (MRI).

[0007] The distal end portion of a probe (e.g., an ENT suction device) can be tracked using a magnetic sensor (e.g., a coil) attached to the distal end, and the tracked position is projected onto a position on the medical image. Hereinafter, tools that can be used with an ENT tracking system as medical devices will be mentioned, and each of such medical devices is assumed to generate an electrical signal in response to a position-dependent magnetic field and thus enable tracking of the position of the medical device within the patient's cavity.

[0008] In practice, the tracking system has a limited number of input channels for receiving signals from the magnetic sensors of the medical devices. When multiple medical devices are being used during a medical procedure, the tracking system may not be able to track all of the medical devices simultaneously. However, at any given time, only a subset of the medical devices may be within the working volume where the medical procedure is being performed, and in many cases, the tracking system may be required to track only a single device or a small number of devices at a time.

[0009] The embodiments of the present disclosure described below provide a method and system that enable automatic detection (during the initial stage) and tracking (during subsequent tracking stages) of medical devices within a working volume. The disclosed technology enables the total number of position sensors of medical devices to exceed the number of input channels of the tracking system by detecting which medical devices are within the working volume and prioritizing the position signals of these devices.

[0010] In an embodiment, the tracking system comprises a smart port splitter (SPS) that selects a subset of the position indication signals input via the input channels from medical devices and sends the subset to a position tracking system (PTS) via the output channels.

[0011] In some embodiments, during the initial stage, the sensors within the medical devices are triaxial sensors that each generate an X position signal, a Y position signal, and a Z position signal. The SPS sends the X position signals of three medical devices to the PTS (e.g., to X output position indication signals, Y output position indication signals, and Z output position indication signals). Based on the three X position signals, the PTS detects, if present, which of the three medical devices is within the working volume. Once such a device is detected, the tracking system enters the tracking stage, and the X position signal, Y position signal, and Z position signal of the detected device are sent to the PTS and then projected onto a medical image.

[0012] In another embodiment, during the initial stage, the SPS continuously scans all the sensors of all the devices in a time-division manner and sends the position indication signals of each device to the PTS. The PTS checks whether any device is within the working volume. When such a device is detected, the tracking system enters the tracking stage, stops the scanning, and tracks the detected medical device.

[0013] In a variant of the embodiments described above in this specification, the SPS comprises a peak detector and a comparator, and the scanning includes only devices whose position indication signal intensity exceeds a preset threshold.

[0014] Description of the System FIG. 1 is a schematic illustration of an otolaryngology (ENT) system 10 according to an embodiment of the present disclosure. The system 10 is used to align a position tracking system 12 with an image (e.g., a computed tomography (CT) image) of an organ 15 (e.g., the head) of a patient 14.

[0015] The position tracking system 12 may comprise, for example, a magnetic tracking system. The Carto® system manufactured by Biosense Webster, Inc., of Irvine, California, uses a tracking system similar to that described herein to track the position and orientation of the distal tip of a probe inserted into or brought near a patient.

[0016] The position tracking system 12 is used to track the position and orientation of one or more instruments, such as a catheter or a guide wire, which are inserted into the patient 14 during a medical procedure on the patient.

[0017] As described below, the position tracking system 12 is also capable of tracking the position and orientation of an alignment probe 16 located outside the patient. The probe 16 is fixedly connected to a handle 18 that can be held by a medical practitioner 20, typically a physician, during use of the system 10. The combination of the probe 16 and the handle 18 forms a rigid probe assembly 22 that facilitates positioning of the probe by the physician 20 to a desired location.

[0018] To make the following description clear and concise, it is assumed that the medical treatment referred to above includes an invasive treatment for the sinuses of patient 14, whereby the ENT system 10 and the position tracking system 12 are assumed to be configured to operate within and around the area of the sinuses. However, systems 10 and 12 may alternatively be configured to operate within and around other areas of the patient, such as the chest, kidneys or abdomen, or other areas. Further, the principles of the present disclosure may be applied in conjunction with other types of tracking systems (not necessarily magnetic), as well as other types of 3D image modalities such as Magnetic Resonance Imaging (MRI).

[0019] The tracking system 12 is operated by a processing and control unit 24 that includes a position tracking system, a smart port splitter (described below), and a processor configured to receive a 3D map (e.g., a CT map) of a target region within the organ 15 of patient 14 and render an image including cross-sections of the organ and indications of the position of medical instruments within the organ. The image is displayed on the monitor 34.

[0020] To track the aforementioned instruments within patient 14, the processing and control unit 24 activates a plurality of magnetic field generators 36, such as coils, via cable 35. In one embodiment, typically applicable when patient 14 is anesthetized and the head 15 is immobile, generators 36, as shown in FIG. 1, are fixed to a frame 42 placed on the bed, laterally to the head of the patient. In an alternative embodiment (not shown) applicable when patient 14 is not anesthetized, generators 36 are fixed relative to each other, and relative to a frame attached to the head 15, or relative to a chair in the physician's office. A triaxial reference coil 41 is fixed to the head 15 and connected to the processing and control unit 24 by cable 43.

[0021] The generator 36 spreads an alternating magnetic field within and around the head 15 of the patient 14, and these magnetic fields generate signals within the magnetic detectors within the instrument and within the probe 16. The signals are returned to the processing and control unit 24 via a cable 44 that connects the probe 16 to the processing and control unit 24, and the processing and control unit 24 analyzes the signals to derive the coordinates of the position and orientation of the instrument and the probe 16 relative to the generator 36. The magnetic field generator 36 thus defines the reference coordinate frame 46 of the magnetic tracking system 12.

[0022] At any given time, some (or all) of the medical instruments not in use may be away from the magnetic field generated by the magnetic field generator 36, while other medical instruments, for example, instruments inserted into the organ 15, may be near the magnetic field. For the purpose of medical instrument tracking, a working volume including the organ 15 is defined, and all instruments within the working volume are exposed to the magnetic field and generate position indication signals, while instruments outside the working volume may or may not generate position indication signals (or, sometimes, may generate weak indication signals that are not useful for tracking purposes).

[0023] The reference coil 41 is within the magnetic field but is located above rather than within the organ 15 and is used as a reference for indicating the movement of the organ. The position of the reference coil 41 is not normally displayed on the monitor 34, and thus, in the following description, the term medical instrument does not include the reference coil 41.

[0024] Selection of Instruments for Display In some embodiments, a plurality of medical instruments may be used in a single medical procedure, although not all at the same time. Each medical instrument may output a plurality of position indication signals, for example, three signals for 3D position coordinates. In an embodiment, the total number of position indication signals exceeds the capacity of the processing and control circuitry. In some embodiments, during a medical procedure, a physician 20 may insert and remove instruments into and from a working volume (e.g., the head 15). The total number of position indication signals output by the instruments within the working volume is compatible with the capacity of the processing and control circuitry, and then the processing and control circuitry can track and display all of the instruments within the working volume. In an embodiment, at any given time, one or fewer medical instruments may be within the working volume.

[0025] FIG. 2 is a block diagram schematically illustrating a tracking display system 200 according to an embodiment of the present disclosure.

[0026] The tracking and display system 200 includes a plurality of medical instruments 202, a smart port splitter (SPS) 202, a position tracking system (PTS) 204, a processor 206, and a display 208.

[0027] Some or all of the medical instruments 200 may be inserted into a patient's organ. The instrument includes one or more position sensing coils that generate an electrical signal indicative of the position of the medical instrument in response to a magnetic field (e.g., generated by the magnetic field generator 36 of FIG. 1). Some medical instruments include position sensing coils that generate a signal indicative of the 3D position of the medical instrument. Other medical instruments may generate a one-dimensional or two-dimensional position signal, and still other medical instruments may generate a signal indicative of the tilt and rotation of the medical instrument (in addition to, or instead of, the position indication signal).

[0028] Examples of suitable medical instruments include a suction device, a probe, a curette, an endoscope, a drill, and the like.

[0029] The SPS202 is configured to receive a position indication signal from a medical instrument via a plurality of input channels and send a subset of the position indication signals to a plurality of output channels that are input to the PTS. In the embodiment shown in FIG. 2, the PTS is configured to track a single medical instrument, and thus the output channels include an X position signal, a Y position signal, and a Z position signal. (Described with reference to FIG. 4) In another embodiment, the SPS is configured to output, and the PTS is configured to track two instruments (however, the PTS only sends the coordinates of a single instrument to the processor 206).

[0030] The subset of input channels is selected according to a switching instruction input from the PTS to the SPS via the control channel 210.

[0031] The PTS204 is configured to calculate the position of the medical instrument in response to the position display signal and send the calculated position to the processor 206. In an embodiment, the calculated position includes the position of the medical instrument within the working volume. In another embodiment, the calculated position includes the positions of two medical instruments. In both embodiments, the PTS only sends the coordinates of one medical instrument to the processor.

[0032] The processor 206 receives a 3D position display of the medical instrument from the PTS and a 3D map of the organ (e.g., generated by a computed tomography (CT) device), and displays a cross-section of the organ together with the display of the medical instrument superimposed on the cross-section.

[0033] In an embodiment, the tracking and display system 200 may be in one of two separate operating phases, namely, a first phase in which the medical instrument is not tracked and a second phase in which the medical instrument within the working volume is tracked. According to the embodiment shown in FIG. 2, the PTS determines the operating phase in response to the position indication. During the first phase, the SPS sends the input channels to the output channels according to the first switching method, and during the second phase, the input channels are sent to the output channels according to the second switching method.

[0034] The first operation stage and the second operation stage may be referred to as the initial stage and the tracking stage, respectively. Similarly, the first switching method and the second switching method may be referred to as the initial switching method and the tracking switching method.

[0035] In an embodiment, the processor 206 may include one or more general-purpose processors programmed in software to perform the functions described herein. The software may be downloaded to the processor in electronic form, for example, via a network or from a host, or alternatively or additionally, the software may be provided and / or stored on a non-transitory tangible medium such as a magnetic memory, an optical memory, or an electronic memory.

[0036] One-dimensional detection In an example of one-dimensional detection, the SPS outputs a position indication signal regarding a single dimension in a plurality of medical instruments while in an initial stage. For example, when there are three medical instruments A, B, and C, the SPS may send the X position signal of medical instrument A to the X position output of the SPS, the X position signal of instrument B to the Y position output of the SPS, and the X position signal of instrument C to the Z position output of the SPS while in the initial stage. The PTS detects the instruments within the working volume (if any) by calculating the position of a combined instrument having X dimensions, Y dimensions, and Z dimensions that are respectively equal to the X dimensions, Y dimensions, and Z dimensions of instruments A, B, and C. When the position in any of the X dimension, Y dimension, and Z dimension is within the working volume, the PTS determines (and sends a signal to the SPS) that the tracking stage should start and the instruments should be detected according to the dimension. Here, the SPS sends the input channels to the output channels according to a second switching method, and all input channels related to the detected instruments are sent (for example, the PTS sends the X position signal, Y position signal, and Z position signal of the detected instrument to the X output channel, Y output channel, and Z output channel). The PTS tracks the position of the detected instrument. (It should be noted that it is optional to use only the X dimension as described in the above example, and in alternative embodiments, any other dimension may be used, including the selection of any dimension from each input instrument (for example, Z of the first instrument, Z of the second instrument, and Y of the third instrument).)

[0037] Time-division multiplex detection In an example of time-division multiplex detection, the SPS sends the input channels to the output channels according to a first switching method including time-division multiplex while in an initial stage. For example, in the first time slot, the X position indication signal, Y position indication signal, and Z position indication signal of the first medical instrument are respectively sent to the X output channel, Y output channel, and Z output channel. In the second time slot, the position indication signal of the second medical instrument is sent to the output channel, and so on (periodically).

[0038] In this way, PTS204 sequentially calculates the positions of the medical instruments. When any of the instruments is within the working volume, PTS determines that the tracking phase should be started (and sends a signal to SPS). Next, SPS sends the position signals of the medical instruments within the working volume to the output channels, and PTS continuously tracks the positions of the instruments.

[0039] In another embodiment of time-division multiplexing detection, SPS202 further comprises a threshold preselector that compares the intensity (e.g., voltage) of the position display signal with a preset threshold. Time-division multiplexing only sends instruments with position display signals exceeding the preset threshold, and thus instruments that are remote from the working volume (e.g., in an instrument tray that is ready for use) will not be multiplexed. This reduces the number of time slots and enables faster detection of instruments within the working volume.

[0040] In some embodiments, SPS is configured to simultaneously output the coordinates of two instruments, namely, a first set of coordinates of the medical instrument being tracked and a second set that is time-division multiplexed between some or all of the other medical instruments. Such an embodiment will be described below with reference to FIG. 6.

[0041] The configuration of the tracking and display system 200 shown in FIG. 2 and described above in this specification is cited as an example. In alternative embodiments, other configurations may be used. In an embodiment, some of the medical instruments bypass SPS and are always input to PTS. In another embodiment, the function of the processor 206 includes position tracking and PTS204 is not implemented.

[0042] FIG. 3 is a block diagram schematically showing a smart port splitter (SPS) 300 configured for one-dimensional detection according to an embodiment of the present disclosure. According to the embodiment illustrated in FIG. 3, SPS300 includes nine input channels connected to the X, Y, and Z position signals of three medical instruments, and three output channels including the X, Y, and Z position signals.

[0043] The SPS receives a stage instruction including an initial stage instruction and three tracking stage instructions via a control channel (e.g., from PTS204 in FIG. 2). During the initial stage, an initial stage display is set, and during the tracking stage, one of three tracking stage displays (first tracking, second tracking, or third tracking) is turned on according to the instrument being tracked.

[0044] The X position signal, Y position signal, and Z position signal from three medical instruments are connected to three switch assemblies 304. Each switch assembly includes four on-off switches, namely, three switches 306 that are on (connected) when the instrument is being tracked during the tracking stage (in response to a tracking selection input), and a switch 308 that is on during the initial stage.

[0045] In an embodiment, switch 306 and switch 308 may include Metal-Oxide-Silicon (MOS) transistors. In an embodiment, a combination of an N-type MOS (NMOS) transistor and a P-type MOS (PMOS) transistor is used. In some embodiments, (e.g., when the position display signal is a complementary differential signal) the position display signal includes a pair of wires, and thus each of switches 306, 308 includes two switches.

[0046] During the initial stage, the input channel is sent to the output channel according to the initial mode, the X position signal of the first medical instrument is sent to the X position output signal, the X position signal of the second medical instrument is sent to the Y position output signal, and the X position signal of the third medical instrument is sent to the Z position output signal. Thus, the PTS receives the 3-D coordinates of a combined virtual instrument having an X position, a Y position, and a Z position that are respectively equal to the X position signal of the first medical instrument, the X position signal of the second medical instrument, and the X position signal of the third medical instrument. By determining whether the position in any dimension is within the working volume, the PTS detects the medical instrument being tracked and activates a tracking stage selection signal accordingly.

[0047] As shown in FIG. 3, the configuration of the one-dimensional detection SPS300 described above is cited as an example. In alternative embodiments, other configurations may be used. In an embodiment, other dimensions of the input instrument, for example, the Y dimension, or a mixture of different dimensions, may be sent at an initial stage.

[0048] FIG. 4 is a block diagram schematically illustrating the structure of the time-division multiplex detection SPS400 according to an embodiment of the present disclosure. The SPS includes an analog switch 402 and a scan counter 404. The SPS receives an X position indication signal, a Y position indication signal, and a Z position indication signal from n instruments via input channels, and outputs the selected X position indication signal, Y position indication signal, and Z position indication signal via an output channel. According to the embodiment illustrated in FIG. 3, the control channel includes a single execution / stop instruction input to the scan counter 404 via the control channel.

[0049] During the initial stage, the PTS sends an execution instruction to the SPS. In response, the scan counter counts continuously (for example, from zero to the number of medical instruments - 1, and then loops back to zero). The count is input to the analog switch 402, and the analog switch sends the position signal of the corresponding medical instrument to the output channel.

[0050] To detect the medical instrument to be tracked, the PTS checks for all input medical instruments whether the instrument is within the working volume. When the medical instrument to be tracked is detected, it enters the tracking stage, the PTS stops the execution output, and the scan counter stops counting. The analog switch continues to send the X position signal, Y position signal, and Z position signal of the detected medical instrument to the PTS for tracking.

[0051] As shown in FIG. 4, the configuration of the time-division multiplex SPS400 described above is cited as an example. In alternative embodiments, other configurations may be used. For example, the PTS may output a scan count to the SPS, and the scan counter may not be used.

[0052] FIG. 5 is a block diagram schematically illustrating the structure of time-division multiplex detection using a threshold-based preselection SPS500 according to an embodiment of the present disclosure.

[0053] The SPS includes an analog switch 502, a peak detector 504, and a microcontroller 506. The SPS receives an X position indication signal, a Y position indication signal, and a Z position indication signal from n instruments via an input channel, and outputs the selected X position indication signal, Y position indication signal, and Z position indication signal via an output channel.

[0054] Unlike the SPS400 (FIG. 4), which scans all input medical instruments and thus may be slow in detecting that an instrument is within the working volume, the SPS500 preselects medical instruments and scans only those medical instruments whose intensity (e.g., voltage or current) of the position indication signal exceeds a preset threshold. Thus, in the embodiment, the SPS500 will detect instruments within the working volume faster.

[0055] Referring again to FIG. 1, the magnetic field generator 36 confines the region around the head 15 of the patient 14. Instruments outside the confined region are typically exposed to a weaker magnetic field than the magnetic field to which the instruments within the confined region are exposed.

[0056] The peak detector 504 is configured to latch the peak in the X position signal of the medical instrument. The latched peak is input to an analog-to-digital converter (ADC) within a microcontroller unit (MCU) 506.

[0057] When the initial stage is on (e.g., the PTS asserts the RUN input), the MCU compares the digital representation of the peak with a preset threshold and sends a selection signal to the analog switch 502 to scan all instruments for which the X - dimensional position indication signal exceeds the threshold. Thus, the SPS500 does not scan medical instruments that do not meet the threshold criteria and thus cannot be present within the working volume, shortening the detection time.

[0058] Simultaneous detection and tracking In some embodiments, the PTS tracks medical instruments simultaneously and checks whether any other medical instruments enter the working volume. When a new instrument is detected within the working volume, the PTS tracks the new instrument.

[0059] FIG. 6 is a block diagram schematically illustrating the structure of an SPS600 and a dual - channel PTS602 configured for simultaneous tracking and detection, according to an embodiment of the present disclosure. The dual - channel PTS602 is configured to track the instruments being tracked simultaneously and check whether the instruments being scanned are within the working volume.

[0060] The SPS600 includes a dual - analog switch 604 and a scan counter 606. The dual - analog switch selects two sets of position indication signals from two medical instruments, where the first set is selected according to the scan selection input and the second set is selected according to the tracking selection input. The scan counter 606 counts continuously, and the scan selection indicates all input medical instruments sequentially. The tracking selection input indicates the instruments to be tracked.

[0061] The dual-channel PTS sends the Xa, Ya, and Za position signals to the processor 202 (Figure 2) for display. At the same time, the dual-channel PTS 602 checks the position display signals Xb, Yb, Zb of the scanned instrument. When the dual-channel PTS discovers that the scanned instrument is within the working volume, the dual-channel PTS sets the tracked instrument to the detected instrument and changes the tracking selection signal to indicate at the detected instrument. Thus, the instrument to be tracked is changed to the newly detected instrument, and the scanning of newer instruments continues.

[0062] The configurations of the SPS 600 and the dual-channel PTS 602 shown in Figure 6 and described above are cited as examples. In alternative embodiments, other configurations may be used. In an embodiment, a triple sample-and-hold circuit outputs the Xb, Yb, and Zb signals. Instead of a dual analog switch, a single analog switch is used, and whenever the scan counter indicates the instrument to be tracked, the sample-and-hold circuit latches the Xa, Ya, and Za signals. In another embodiment, the dual-channel position tracking system 602 sends two SPS output channels to the processor, and the processor calculates the position and presents the tracked tool to the display.

[0063] In still other embodiments, a hybrid SPS that employs both threshold-based instrument preselection (as described above with reference to Figure 5) and dual-channel tracking (as described above with reference to Figure 6) may be used.

[0064] Figure 7 is a flowchart 700 that schematically illustrates a one-dimensional detection method for tracking a medical instrument according to an embodiment of the present disclosure. The flowchart is executed by the tracking and display system 200 (Figure 2).

[0065] The flowchart starts with the X signal transfer operation 702 (typically at power-on), and the SPS sends the X position display signal of the input medical device to the X output, Y output, and Z output (and thus to the PTS). For example, if there are three medical devices A, B, and C, the SPS sends the X-dimensional position indication signal of device A to the X output position indication signal, the X-dimensional signal of device B to the Y output, and the X-dimensional signal of device C to the Z output. Thus, the PTS receives the X position display signal, Y position display signal, and Z position display signal of the virtual combined-dimensional device that combines the three X-dimensional signals of the three devices.

[0066] Next, in the device detection operation 704, the PTS checks whether the combined device is within the working volume in any of its three dimensions. In some embodiments, to determine whether the device is within the working volume, the PTS checks that the X position signal is between the X minimum value and the X maximum value, the Y position signal is between the Y minimum value and the Y maximum value, and the Z position signal is between the Z minimum value and the Z maximum value. Optionally, in some embodiments, the processor (e.g., processor 206, FIG. 2) calculates the position of the sensor by triangulation of the magnetic field transmitted from the sensor. However, when the tracking and display system is in its initial stage, the PTS checks whether any of the X position display signal, Y position display signal, and Z position display signal is between the X minimum value and the X maximum value.

[0067] As long as none of the position indication signals in any dimension are within the working volume, the tracking and display system remains in operation 704. When one of the X position display signal, Y position display signal, or Z position display signal is within the working volume, the tracking and display system enters the tracking stage, and in the detected device selection operation 706, the PTS sends a selection code to the SPS according to the detected device. For example, if the Y position signal of the composite device is within a predetermined X-dimensional working volume, the PTS sends the code of device B, and the SPS sends the X position display signal, Y position display signal, and Z position display signal of device B to the PTS while in the tracking stage.

[0068] In the detection instrument tracking operation 708, the SPS continuously transmits the X-position display signal, Y-position display signal, and Z-position display signal of the detected instrument to the PTS. In the operation 710 to confirm the lost tracking, the PTS checks whether the tracked instrument is within the working volume. If not, the tracking and display system restarts the initial stage and enters the X-signal transfer operation 702 again.

[0069] In the operation 710, if the instrument to be tracked is still within the working volume, the tracking and display system enters the display operation 712, and the position of the instrument to be tracked is overlaid on the CT-generated image of the organ displayed on the monitor 208 (Figure 2). Next, the tracking and display system enters the operation 708 again and stays within the loop including operations 708 - 710 - 712 until the instrument to be tracked exits the working volume.

[0070] The configuration of the flowchart 700 shown in Figure 7 and described above in this specification is cited as an example. In alternative embodiments, other configurations may be used. In some embodiments, more than three instruments may be used, and the PTS checks more than one coupled-dimensional instrument. In another embodiment, a threshold pre-selection (as described with reference to Figure 5) is used in conjunction with the flowchart 700. In some embodiments, some of the instruments include less than three position indication signals, and in other embodiments, some or all of the instruments may include inclination and rotation indication signals in addition to, or instead of, some of the position indication signals.

[0071] Figure 8 is a flowchart 800 schematically illustrating a time-division multiplex detection method for tracking a medical instrument according to an embodiment of the present disclosure. The flowchart is executed by the tracking and display system 200 (Figure 2).

[0072] The flowchart starts with the full input scanning operation 802. The tracking and display system is in the initial mode. The PTS issues a scanning instruction (via the control channel), and in response, the SPS sequentially sends the position signals of all the instruments input via the input channel to the output channel. In an embodiment, the scanning is performed by providing increasing selection codes to the analog multiplexer to sequentially send the position signals of all the inputs. After selecting the last instrument, the code is reset to select the first instrument (and then continues to increase).

[0073] Next, in the Check-Scanned-Instrument operation 804, the PTS checks whether the scanned instrument is within the working volume (in the X, Y, and Z dimensions). If the scanned instrument does not exist within the working volume, the tracking and display system returns to operation 802 to continue scanning the input medical instruments.

[0074] In operation 804, if the scanned instrument exists within the working volume, the tracking and display system enters the tracking phase to track the detected instrument. The PTS stops the scanning instruction and sends the position of the tracked instrument to the processor 206 (Figure 2) for display.

[0075] The instrument being tracked may move or exit the working volume during the tracking phase. In the Check-Tracked-Instrument operation 808, the PTS checks whether the tracked instrument is still within the working volume, and if so, returns to operation 806. In operation 808, if the instrument being tracked no longer exists within the working volume, the tracking and display system returns to the initial stage in operation 802.

[0076] Illustrated in FIG. 8, the configuration of flowchart 800 described above in this specification is cited as an example. In alternative embodiments, other configurations may be used. In some embodiments, the scan does not include one or two instruments (e.g., reference coil 41 of FIG. 1) that are always sent. In another embodiment, threshold preselection (as described with reference to FIG. 5) is used in conjunction with flowchart 800. In some embodiments, some of the instruments include less than three position indication signals, and in other embodiments, some or all of the instruments may include inclination and rotation indication signals in addition to, or instead of, some of the position indication signals.

[0077] The embodiments described herein primarily address ENT applications, but the methods and systems described herein can also be used for other applications such as cardiac, neurological, or ophthalmic applications.

[0078] The various elements of the tracking and display system 200 (FIG. 2) may be implemented using suitable hardware such as one or more application-specific integrated circuits (ASICs) or field-programmable gate arrays (FPGAs), using software, using hardware, or using a combination of hardware and software elements.

[0079] Accordingly, it will be understood that the above-described embodiments are given by way of example, and the present disclosure is not limited to those particularly shown and described above. Rather, the scope of the present disclosure includes both the various combinations and sub-combinations of the features described above, as well as those variations and modifications thereof that would occur to those skilled in the art upon reading the foregoing description and that are not disclosed in the prior art.

Examples

[0080] Example 1: The device includes a first plurality of input channels, a second plurality of output channels, a control channel, and a switching circuit. The input channels are configured to receive position signals from a plurality of medical instruments disposed within a patient's organ. The output channels are configured to send one or more position signals to a position tracking system. The control channel is configured to receive a control signal from the position tracking system. The switching circuit sends at least some of the position signals to at least some of the output channels according to a first switching scheme, and in response to the position signals sent according to the first switching scheme, receives, via the control channel, from the position tracking system a control signal indicating a given medical instrument identified as being disposed within the working volume of the position tracking system, and is configured to switch to a second switching scheme in which all of the position signals of the given medical instrument are sent to at least some of the output channels.

[0081] Example 2: The device according to Example 1, wherein the switching circuit is configured to send at least a uniaxial position signal from each medical instrument according to the first switching scheme.

[0082] Example 3: The device according to Example 1, wherein the switching circuit is configured to alternate within a time among the position signals of the plurality of medical instruments according to the first switching scheme.

[0083] Example 4: The device according to Example 3, further comprising a detector configured to cause the switching circuit to switch to the second switching scheme when it is detected that the given medical instrument is within the working area.

[0084] Example 5: The device according to Example 4, wherein the detector is configured to detect that the given medical instrument is within the working area by comparing at least some amplitudes of the position signals with a threshold value.

[0085] Example 6: When the switching circuit in accordance with the first switching method, (i) sends all the position signals of a specific medical instrument different from the given medical instrument to the output channel, and (ii) alternates within a time among the position signals of the medical instruments other than the specific medical instrument, configured to stop sending all the position signals of the specific medical instrument and instead send all the position signals of the given medical instrument, in accordance with the second switching method, the apparatus according to Embodiment 1.

[0086] Embodiment 7: The output channel includes three output channels arranged at a single output port, and each of the output channels is configured to output respective single-axis position signals, the input channel includes nine input channels arranged at three input ports, and each of the input channels is configured to receive respective single-axis position signals, the apparatus according to Embodiment 1.

[0087] Embodiment 8: The output channel includes six output channels arranged at two output ports, and each of the output channels is configured to output respective single-axis position signals, the input channel is arranged at three or more input ports, each of the input ports consists of three input channels, and each of the input channels is configured to receive respective single-axis position signals, the apparatus according to Embodiment 1.

[0088] Embodiment 9: When the switching circuit after switching to the second switching method, further configured to switch to a third switching method of receiving a subsequent control signal indicating another medical instrument identified as being arranged within the working volume via the control channel and sending all the position signals of the another medical instrument to at least some of the output channels, the apparatus according to Embodiment 1.

[0089] Embodiment 10: The method includes receiving position signals from a plurality of medical instruments disposed within a patient's organ on a first plurality of input channels. One or more of the position signals are sent to a position tracking system on a second plurality of output channels. A control signal is received from the position tracking system on a control channel. At least some of the position signals are sent to at least some of the output channels according to a first switching scheme. A control signal indicating a given medical instrument identified as being disposed within the working volume of the position tracking system is received from the position tracking system via the control channel in response to the position signal sent according to the first switching scheme. A switch to a second switching scheme in which all of the position signals of the given medical instrument are sent to at least some of the output channels is performed.

[0090] 〔Embodiment〕 (1) An apparatus, a first plurality of input channels configured to receive position signals from a plurality of medical instruments disposed within a patient's organ, a second plurality of output channels configured to send one or more of the position signals to a position tracking system, a control channel configured to receive a control signal from the position tracking system, a switching circuit, wherein the switching circuit sends at least some of the position signals to at least some of the output channels according to a first switching scheme, receives, via the control channel, from the position tracking system, a control signal indicating a given medical instrument identified as being disposed within the working volume of the position tracking system, in response to the position signal sent according to the first switching scheme, and is configured to switch to a second switching scheme in which all of the position signals of the given medical instrument are sent to at least some of the output channels. An apparatus comprising the switching circuit. (2) The apparatus according to Embodiment 1, wherein the switching circuit is configured to send at least a uniaxial position signal from each medical instrument according to the first switching method. (3) The apparatus according to Embodiment 1, wherein the switching circuit is configured to alternate between the position signals of the plurality of medical instruments within a time according to the first switching method. (4) The apparatus according to Embodiment 3, further comprising a detector configured to cause the switching circuit to switch to the second switching method when it is detected that the given medical instrument is within the working area. (5) The apparatus according to Embodiment 4, wherein the detector is configured to detect that the given medical instrument is within the working area by comparing at least some amplitudes of the position signals with a threshold value.

[0091] (6) The switching circuit is configured to, according to the first switching method, (i) send all the position signals of a specific medical instrument different from the given medical instrument to the output channel, and (ii) alternate within a time between the position signals of the medical instruments other than the specific medical instrument, and configured to, according to the second switching method, stop sending all the position signals of the specific medical instrument and instead send all the position signals of the given medical instrument, as described in Embodiment 1 of the apparatus. (7) The output channel includes three output channels arranged at a single output port, and each of the output channels is configured to output a respective uniaxial position signal, and the input channel includes nine input channels arranged at three input ports, and each of the input channels is configured to receive a respective uniaxial position signal, as described in Embodiment 1 of the apparatus. (8) The output channel includes six output channels arranged at two output ports, and each of the output channels is configured to output a respective uniaxial position signal, The apparatus according to Embodiment 1, wherein the input channel is arranged at three or more input ports, each of the input ports consists of three input channels, and each of the input channels is configured to receive a respective uniaxial position signal. (9) After the switching circuit switches to the second switching method, via the control channel, receives a subsequent control signal indicating another medical instrument identified as being disposed within the working volume, and further configured to switch to a third switching method in which all of the position signals of the another medical instrument are sent to at least some of the output channels, the apparatus according to Embodiment 1. (10) A method, the method comprising: Receiving position signals from a plurality of medical instruments disposed within a patient's organ on a first plurality of input channels; Sending one or more of the position signals to a position tracking system on a second plurality of output channels; Receiving a control signal from the position tracking system on a control channel; Sending at least some of the position signals to at least some of the output channels according to a first switching method; In response to the position signals sent according to the first switching method, receiving from the position tracking system, via the control channel, a control signal indicating a given medical instrument identified as being disposed within the working volume of the position tracking system; Switching to a second switching method in which all of the position signals of the given medical instrument are sent to at least some of the output channels.

[0092] (11) The method according to Embodiment 10, wherein sending at least some of the position signals according to the first switching method includes sending at least uniaxial position signals from each medical instrument. (12) The method according to embodiment 10, wherein sending at least some of the position signals according to the first switching scheme includes alternating in time among the position signals of the plurality of medical instruments. (13) The method according to embodiment 12, wherein the switching to the second switching scheme is performed when it is detected that the given medical instrument is within the working area. (14) The method according to embodiment 13, wherein detecting that the given medical instrument is within the working area includes comparing at least some of the amplitudes of the position signals with a threshold value. (15) Sending at least some of the position signals according to the first switching scheme includes (i) sending all of the position signals of a specific medical instrument different from the given medical instrument to the output channel, and (ii) alternating in time among the position signals of the medical instruments other than the specific medical instrument. Switching to the second switching scheme includes, according to the second switching scheme, stopping the transmission of all of the position signals of the specific medical instrument and instead sending all of the position signals of the given medical instrument, the method according to embodiment 10.

[0093] (16) The output channel includes three output channels arranged at a single output port, and each of the output channels is configured to output a respective single-axis position signal. The input channel includes nine input channels arranged at three input ports, and each of the input channels is configured to receive a respective single-axis position signal, the method according to embodiment 10. (17) The output channel includes six output channels arranged at two output ports, and each of the output channels is configured to output a respective single-axis position signal. The input channel is arranged at more than three input ports, each of the input ports consists of three input channels, and each of the input channels is configured to receive a respective single-axis position signal, the method according to embodiment 10. After switching to the second switching method, receiving, via the control channel, a subsequent control signal indicating another medical device identified as being disposed within the working volume; and switching to a third switching method in which all of the position signals of the other medical device are sent to at least some of the output channels, the method of embodiment 10 further comprising.

Claims

1. An apparatus comprising: a first plurality of input channels configured to receive position signals from a plurality of medical instruments positioned within an organ of a patient; a second plurality of output channels configured to transmit one or more of the position signals to a position tracking system; a control channel configured to receive control signals from the position tracking system; A switching circuit, comprising: directing at least some of the position signals to at least some of the output channels according to a first switching scheme; receiving a control signal from the position tracking system over the control channel in response to the position signal sent according to the first switching scheme, the control signal being indicative of a given medical instrument identified as being located within a working volume of the position tracking system; and switching circuitry configured to switch to a second switching scheme in which all of the position signals for the given medical instrument are routed to at least some of the output channels.

2. The apparatus of claim 1 , wherein the switching circuitry is configured to transmit at least a single axis position signal from each medical instrument in accordance with the first switching scheme.

3. The apparatus of claim 1 , wherein the switching circuitry is configured to alternate in time between the position signals of the plurality of medical instruments in accordance with the first switching scheme.

4. 4. The apparatus of claim 3, further comprising a detector configured to cause the switching circuitry to switch to the second switching scheme upon detecting that the given medical instrument is within the working area.

5. The apparatus of claim 4 , wherein the detector is configured to detect that the given medical instrument is within the working region by comparing amplitudes of at least some of the location signals to a threshold value.

6. The switching circuit, According to the first switching scheme, (i) sending all of the position signals of a particular medical device other than the given medical device to the output channel, and (ii) alternating in time between the position signals of the medical devices other than the particular medical device; 2. The device of claim 1, configured to stop transmitting all of the location signals of the particular medical device and instead transmit all of the location signals of the given medical device in accordance with the second switching scheme.

7. the output channels include three output channels arranged on a single output port, each of the output channels configured to output a respective single-axis position signal; The apparatus of claim 1 , wherein the input channels include nine input channels arranged on three input ports, each of the input channels configured to receive a respective single-axis position signal.

8. the output channels include six output channels arranged on two output ports, each of the output channels configured to output a respective single-axis position signal; 2. The apparatus of claim 1, wherein the input channels are arranged in three or more input ports, each of the input ports consisting of three input channels, each of the input channels configured to receive a respective single-axis position signal.

9. The switching circuit, 2. The device of claim 1, further configured to receive a subsequent control signal via the control channel indicative of another medical instrument identified as being located within the working volume after switching to the second switching scheme, and to switch to a third switching scheme in which all of the position signals of the other medical instrument are sent to at least some of the output channels.

10. 1. A method, comprising: receiving location signals from a plurality of medical instruments positioned within an organ of a patient on a first plurality of input channels; transmitting one or more of the location signals on a second plurality of output channels to a position tracking system; receiving a control signal from the position tracking system over a control channel; routing at least some of the position signals to at least some of the output channels according to a first switching scheme; receiving a control signal from the position tracking system over the control channel in response to the position signal sent according to the first switching scheme, the control signal being indicative of a given medical instrument identified as being located within a working volume of the position tracking system; and switching to a second switching scheme in which all of the position signals for the given medical instrument are routed to at least some of the output channels.

11. The method of claim 10 , wherein sending at least some of the position signals in accordance with the first switching scheme comprises sending at least a single axis position signal from each medical instrument.

12. The method of claim 10 , wherein sending at least some of the location signals in accordance with the first switching scheme includes alternating in time between the location signals of the plurality of medical devices.

13. The method of claim 12 , wherein switching to the second switching scheme is performed upon detecting that the given medical instrument is within the working area.

14. The method of claim 13, comprising detecting when the given medical instrument is within the working area by comparing amplitudes of at least some of the location signals to a threshold.

15. sending at least some of the position signals in accordance with the first switching scheme includes: (i) sending all of the position signals of a particular medical device other than the given medical device to the output channel; and (ii) alternating in time between the position signals of the medical devices other than the particular medical device; 11. The method of claim 10, wherein switching to the second switching scheme comprises ceasing transmission of all of the location signals of the particular medical device and instead sending all of the location signals of the given medical device in accordance with the second switching scheme.

16. the output channels include three output channels arranged on a single output port, each of the output channels configured to output a respective single-axis position signal; The method of claim 10 , wherein the input channels include nine input channels arranged on three input ports, each of the input channels configured to receive a respective single-axis position signal.

17. the output channels include six output channels arranged on two output ports, each of the output channels configured to output a respective single-axis position signal; 11. The method of claim 10, wherein the input channels are arranged in three or more input ports, each of the input ports consisting of three input channels, each of the input channels configured to receive a respective single-axis position signal.

18. 11. The method of claim 10, further comprising, after switching to the second switching scheme, receiving a subsequent control signal via the control channel indicative of another medical instrument identified as being located within the working volume, and switching to a third switching scheme in which all of the position signals of the other medical instrument are routed to at least some of the output channels.

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