Acoustic wave catheter tracking system

Abstract

An acoustic wave catheter tracking system includes an acoustic wave emitter, an acoustic wave receiver, and a spectrum analyzer. An audio transmitter may be configured to transmit an audio signal from a proximal end of a catheter along an empty interior length of the catheter for identification. The receiver may be configured to receive an audio return signal. A spectrum analyzer may be configured to analyze the audio return signal to facilitate determination of a remote location of the conduit. The acoustic conduit tracker may use the audio return signal to determine an estimated length of the conduit.

Description

Technical Field

[0001] The present invention relates to an acoustic waveguide tracking system. Background Art

[0002] There are some commonly used electronic wire tracing tools, called "wire finders," that can easily identify a specific wire or cable within a conduit. However, there is no simple method or device to identify a specific empty conduit from another empty conduit. Summary of the invention

[0003] The present invention provides an acoustic waveguide tracking system that meets this need by using acoustic waves sent through the guide tube to easily identify the remote or distant end of a particular guide tube from a large number of similar guide tubes in a given area. As non-limiting examples, such acoustic waves can be provided as an audible tone or an audible pulse.

[0004] While the acoustic waveguide tracking system can easily point to or identify a particular catheter of interest at a particular location, whether the catheter is in a group of other catheters or just by itself, there is still the logistical issue of first locating the general area, equipment room, or other terminal location of the catheter's distal end. Thus, the acoustic waveguide tracking system can also facilitate locating the distal end of a particular catheter in a group of empty or nearly empty catheters.

[0005] The present invention discloses an acoustic waveguide tracking system for determining the identification and location of an empty conduit. The acoustic waveguide tracking system can use acoustic emission to locate the identification end and / or the terminal end of a conduit from a large number of empty conduits or terminal positions.

[0006] The acoustic waveguide tracking system can also be operated in a "pipe length determination mode" to allow the acoustic waveguide tracking system to automatically calculate the estimated total length of the pipe. The acoustic waveguide tracking system can automatically calculate the estimated length of the pipe by transmitting an acoustic pulse and then listening, and calculating the time delay until the transmitted pulse returns to the transmission location. In this exemplary embodiment, the estimated pipe length is calculated using the measured propagation delay time for a specific inner diameter size.

[0007] An acoustic waveguide tracking system for determining the identification and location of an empty conduit by locating the marker and / or terminal end of the conduit from a large number of empty conduits or terminal locations using acoustic transmissions can be configured to optimize or adjust the transmitted acoustic frequency and / or pulse rate of the transmitted acoustic transmissions based on the internal dimensions of the conduit used to locate its terminal end. According to an embodiment, the acoustic waveguide tracking system can automatically sense or determine that a conduit adapter of a particular size has been installed to the transmitting device, wherein the acoustic waveguide tracking system can use this information to optimize the transmitted signal.

[0008] According to another embodiment, a self-powered acoustic waveguide tracking system can be configured to attach to a commonly used wire "snake" or wire pulling tool. This self-contained acoustic waveguide tracking system can be pushed or guided through the catheter while actively emitting one or more unique tones and / or rhythmic patterns. With this embodiment, the acoustic waveguide tracking system emitting the identification sound can be placed closer to the terminal end of the catheter.

[0009] The present invention discloses an acoustic waveguide tracking system comprising a combined acoustic wave transmitter, an acoustic wave receiver and a spectrum analyzer. The transmitter may be an audio transmitter configured to transmit an acoustic signal from the proximal end of the catheter along the inner length of the empty catheter. The receiver may be an audio receiver configured to receive an acoustic return signal. The spectrum analyzer may be an audio spectrum analyzer configured to analyze the return acoustic signal and thereby facilitate determination of the location of the distal end of the catheter.

[0010] According to certain aspects, a spectrum analyzer of the acoustic waveguide tracker can be configured to use the return signal to determine an estimated length of the guide tube. For example, according to an embodiment, the acoustic spectrum analyzer can determine the estimated length of the guide tube based on one or more acoustic differences, such as a particular acoustic frequency attenuation between the transmitted acoustic signal and the returned acoustic signal. According to another embodiment, the spectrum analyzer can determine the estimated length of the guide tube based on the following factors: the delay between the time when the acoustic pulse is transmitted and the time when the echo pulse is returned; the time when the transmitted pulse decays to a predetermined level; the change of the harmonic characteristics; and / or the attenuation of a portion of the total spectrum of the transmitted acoustic signal.

[0011] According to another aspect, the transmitter of the acoustic waveguide tracker can be configured to transmit a variety of different signals. According to one embodiment, the transmitter can be configured to pulse the audio signal at a fixed pulse rate or a variable pulse rate. According to another embodiment, the transmitter can be configured to transmit the audio signal at a single frequency. Alternatively, the transmitter can be configured to transmit the audio signal having multiple audio frequency extensions. According to another embodiment, the transmitter can be configured to transmit a first audio signal having a first spectral bandwidth, a first pulse repetition rate, and / or a first pulse frequency characteristic. In addition, the transmitter can be configured to transmit a first audio signal having a first spectral bandwidth, a first pulse repetition rate, and / or a first pulse frequency characteristic, and can be further configured to transmit a second audio signal having a second spectral bandwidth, a second pulse repetition rate, and / or a second pulse frequency characteristic. According to another embodiment, the transmitter can be configured to transmit sound waves including white noise along the length of the catheter.

[0012] According to one aspect, the acoustic waveguide tracker can be configured to automatically determine the inner diameter of the catheter. According to one embodiment, the catheter tracker can be configured to emit a first acoustic signal when the catheter has a first inner diameter and emit a second acoustic signal when the catheter has a second inner diameter.

[0013] According to other embodiments, the acoustic waveguide tracker may be configured to be at least partially inserted into the proximal end of the catheter. Alternatively, the acoustic waveguide tracking system may be configured to be fully inserted into the catheter to allow it to be tracked along the interior of the catheter.

[0014] According to certain aspects, a method for tracking a catheter comprises: transmitting an acoustic wave signal from a proximal end of the catheter along the interior length of an empty catheter; receiving an acoustic wave return signal at the proximal end of the catheter; and analyzing the acoustic wave return signal to determine an estimated length of the catheter. The acoustic wave signal can be a continuous audio signal and / or a pulsed audio signal. According to certain embodiments, the analyzing step can include determining the estimated length of the catheter based on one or more differences between the acoustic wave transmit signal and the acoustic wave return signal. For example, the analyzing step can include determining the estimated length of the catheter based on the following factors: a delay between the time of the transmit pulse and the time of the return echo pulse; the time for the transmit pulse to decay to a predetermined level; a change in harmonic characteristics; and / or an attenuation of a portion of the total frequency spectrum of the acoustic transmit signal.

[0015] According to other embodiments, the transmitting step may include: transmitting a signal having a pulse signal; transmitting a signal having a single audio frequency; transmitting a signal having a plurality of audio frequency extensions; transmitting a signal having a first spectral bandwidth; transmitting a signal having a first pulse repetition rate; and / or transmitting a signal having a first pulse frequency characteristic. According to another embodiment, the transmitting step may include: transmitting a first signal having a first spectral bandwidth, a first pulse repetition rate, and / or a first pulse frequency characteristic, and then transmitting a second signal having a second spectral bandwidth, a second pulse repetition rate, and / or a second pulse frequency characteristic. According to another embodiment, the transmitting step may include transmitting a "white noise" sound wave along the length of the catheter.

[0016] According to another aspect, the method of tracking a catheter can further include the audio transmitter automatically determining the inner diameter of the catheter based on the detected catheter size and selecting an optimized audio frequency. In another aspect, the method of determining the transmitted audio operating frequency can be manually selected based on a manual catheter diameter size determination. In addition, the transmitting step can include transmitting a first signal when the catheter has a first inner diameter, and transmitting a second signal when the catheter has a second inner diameter.

[0017] According to a final aspect, the acoustic waveguide tracker may include an acoustic transmitter configured to transmit an acoustic signal along an interior length of a hollow conduit, wherein the acoustic transmitter is configured to be mounted within the hollow electrical conduit and further configured to be attached to one end of a flexible transmitter positioning wire feed mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 An acoustic waveguide tracking system according to an embodiment of the present invention is schematically shown.

[0019] Figure 2 Schematic display Figure 1 Side view of the acoustic waveguide tracking system.

[0020] Figure 3 Schematic display Figure 1 End view of the acoustic waveguide tracking system.

[0021] Figure 4 FIG. 1 schematically shows a physically introduced acoustic waveguide tracking system according to another embodiment of the present invention.

[0022] Figure 5 is a flow chart showing a method of operating an acoustic waveguide tracking system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention discloses an acoustic waveguide tracking system for determining the length of an empty catheter, for locating the terminal (or remote) of a catheter from a plurality of possible terminal positions, and / or for identifying the terminal of a particular catheter from a plurality of other catheters. The acoustic waveguide tracking system utilizes one or more acoustic wave emissions traveling within the catheter. As used herein, an "acoustic wave signal" refers to an acoustic wave having one or more synchronous frequencies. As used herein, an "audio frequency signal" refers to an acoustic wave having a frequency within the range of human hearing, for example, a typical frequency range is 20 to 20,000 Hz.

[0024] refer to Figure 1 , shows an acoustic waveguide tracking system 100 according to the present invention. The system 100 comprises an acoustic wave transmitter 300, an acoustic wave receiver 301 and an acoustic wave spectrum analyzer 302. The acoustic wave transmitter 300 is configured to transmit an acoustic wave signal, the acoustic wave receiver 301 is configured to receive an acoustic wave signal, and the acoustic wave spectrum analyzer 302 is configured to analyze the received acoustic wave signal. The transmitter, the receiver and / or the spectrum analyzer may be co-located in the acoustic waveguide tracking device body 101.

[0025] According to one aspect, the acoustic transmitter 300 is an acoustic transmitter, the acoustic receiver 301 is an acoustic receiver, and the acoustic spectrum analyzer 302 is an acoustic spectrum analyzer. The acoustic transmitter 300 can be specifically configured to transmit an acoustic signal into and along the inner length of the catheter. In addition, the acoustic transmitter 300 can be configured to transmit a variety of acoustic signals. For example, the acoustic transmitter 300 can be configured to: pulse the acoustic transmission signal, transmit the acoustic signal at a single frequency, transmit the acoustic signal with a multi-frequency spread, and transmit the acoustic signal in a sequentially changing single frequency manner. Therefore, the acoustic transmitter 300 can be configured to transmit an acoustic signal with a specific spectrum bandwidth, a defined pulse repetition rate, and / or a defined pulsed acoustic frequency characteristic. Alternatively, the audio transmitter 300 may be configured to transmit multiple audio signals, for example, the audio transmitter 300 may be configured to transmit a first audio signal having a first defined spectral bandwidth, a first defined pulse repetition rate, and / or a first defined pulse frequency characteristic, and the audio transmitter 300 may be configured to transmit a second defined audio transmission signal having a second defined spectral bandwidth, a second defined pulse repetition rate, and / or a second defined pulse frequency characteristic. In some cases, the audio transmitter 300 may be configured to combine one or more audio signals. In addition, those skilled in the art will appreciate, with the benefit of the present disclosure, that the audio transmitter 300 may be configured to modulate the transmitted signal, for example, by spectral sweeping, increasing or decreasing amplitude, changing pulse characteristics, etc.

[0026] The audio receiver 301 can be specifically configured to receive an audio return signal from the inner length of the catheter. As used herein, a "return signal" refers to an acoustic wave originating from a transmit signal at an initial location (usually the proximal end of the catheter) that subsequently reflects from one or more surfaces or otherwise interacts, causing the spectral characteristics of the original transmit signal to change or become distorted. For example, the return signal can have different or inconsistent audio characteristics throughout the spectrum, such as different pulse rates caused by the addition of echoes, and / or one or more audio frequencies that have been attenuated relative to the original transmit signal. In addition, the return audio signal can include multiple, possibly overlapping and / or time-shifted, distorted versions (e.g., echoes) of the original transmission signal.

[0027] The audio spectrum analyzer 302 may be specifically configured to analyze the audio return signal to facilitate determining the location of the distal end of the catheter. According to one embodiment, the audio spectrum analyzer 302 may be specifically configured to analyze the difference between the audio transmission signal and the audio return signal to facilitate determining the location of the distal end of the catheter. The audio spectrum analyzer 302 may determine the delay between the time of the transmission pulse and the time of the return echo pulse; the time for the transmission pulse to decay to a predetermined level; the change in harmonic characteristics; and / or the decay of a portion of the total spectrum of the audio transmission signal.

[0028] According to one aspect, the acoustic waveguide tracking system 100 can be configured to determine an estimated length of the guide tube based on an analysis of the return signal by the audio spectrum analyzer 302. The estimated length of the guide tube can be further determined by the spectrum analyzer 302 based on the following factors: based on the difference between the audio transmission signal and the audio return signal; between different audio frequencies, based on the difference in the transmitted audio frequency and subsequent effects, such as the time delay between the time of the transmitted pulse and the time of the return echo pulse; based on the time it takes for the transmitted pulse to decay to a predetermined level, based on the change in harmonic characteristics; and / or, based on the decay of a portion of the total spectrum of the audio transmission signal.

[0029] For example, the estimated length of a duct can be determined by utilizing an established formula, such as velocity = distance / time. Since it is well known that the speed of sound at sea level is approximately 340 meters per second (at standard temperature and pressure), we can easily solve for the distance value by knowing that the velocity is approximately 340 meters per second and the echo time (divided by 1 / 2 to compensate for the return distance). It should be noted that the far end of the duct may or may not be capped. If the end is indeed capped, the receiver will detect a strong echo. However, if the far end is not capped, the spectrum analyzer will detect distortion when the sound wave leaves the end of the duct, and the time elapsed for this change will be used as the time value. The system can distinguish whether the far end is capped by the lack of a significant echo and / or higher overall attenuation. If the system determines that the duct under test is not capped, the detected distance value will not be halved as it would be in the case of a capped duct.

[0030] Different sized catheters have inherently different degrading effects on various audio frequencies, and their measurements may result in attenuation, distortion, etc., so it is important to optimize the audio frequencies used by the audio transmitter based on the internal dimensions of the catheter. Therefore, when determining the estimated length of the catheter, the size of the catheter's inner diameter can be provided as an input to the acoustic waveguide tracking system 100. According to one embodiment, the acoustic waveguide tracker can automatically optimize, adjust and / or calibrate its circuits for the specific catheter size being tracked. Such size-dependent transmission audio characteristics can include audio spectrum bandwidth, pulse repetition rate, pulsed audio frequency, etc. A single transmission frequency can be used, or multiple frequency extensions can be used to determine the estimated catheter length by analyzing the return effects of various frequencies.

[0031] Thus, according to certain aspects, as an initial step, the acoustic waveguide tracking system 100 can be configured to determine the size of the catheter of interest. Figures 1 to 3, the acoustic waveguide tracking system 100 may include one or more adapters 106A, 106B, 106C (collectively referred to as 106). One or more adapters 106 may provide a range of sizes that are configured to fit (e.g., slide fit, locating fit, snap fit, press fit, etc.) into the end of a catheter having a standard inner diameter (1 inch / 2 inches / 3 inches, etc.). Therefore, an adapter sized to fit into one or more correspondingly sized catheters can be attached (e.g., by a slide fit, locating fit, snap fit, press fit, etc.) to an end 108 or output port of the acoustic waveguide tracking device body 101. For example, the acoustic waveguide tracking device body can be provided with an index key protrusion 109 that is configured to engage with an adapter recess 110.

[0032] According to one embodiment, the acoustic waveguide tracing system 100 may be equipped with a manual catheter size selector knob 103 or switch on the acoustic waveguide tracing device body 101. This selector knob 103, when manually set by the user, will inform the acoustic waveguide tracing system which adapter size 106A, 106B, etc. is installed to the acoustic waveguide tracer device body 101, and thus select the transmitted acoustic frequency characteristics appropriate for a given catheter size.

[0033] Other embodiments may allow for automatic determination of catheter adapter size 106. For example, conductive strips 107A, 107B, 107C, etc. (collectively 107) may be attached to the inner edge of each adapter 106. For each different size adapter, the location of each conductive strip 107A, 107B, etc. may be located at a different offset position relative to index key 109 and adapter recess 110. Figure 1 as well as Figure 3 As shown, the body 101 of the acoustic waveguide tracking device can be correspondingly provided with a plurality of different sets of sizing contacts 105A, 105B, 105C, etc. (collectively referred to as 105). For any given size of adapter, the conductive strip 107 will align with and contact the appropriate sizing contacts on the device body 101. In this way, by electrically bridging only one pair of sizing contacts 105A, 105B, etc., each different catheter size adapter 106A, 106B, etc. will automatically inform the acoustic waveguide tracking system which catheter size is being tracked.

[0034] like Figure 1As shown, when the index key 109 of the acoustic waveguide tracker body is mated with the adapter recess 110, for example, with a 2-inch catheter size adapter 106A, the conductive strip 07A for the adapter 106A will mate with, for example, the contact 105A on the device body. Therefore, closing this particular circuit will automatically indicate to the acoustic waveguide tracking system 100 that a 2-inch adapter has been mated. A switch 104 can be provided to inform the acoustic waveguide tracking system whether to use a manual or automatic catheter sizing method.

[0035] In operation, at least a portion of the acoustic waveguide tracking system 100 (eg, the adapter 106 attached to the body 101) can be configured to cause insertion into the proximal end of the catheter being tracked. Figure 1 A power switch 102 may be provided to start the acoustic waveguide tracking system 100. Figure 2 , the function switch 202 can be set to select a specific operating mode of the acoustic waveguide tracking system 100. For example, when in the "length" mode 203, the acoustic waveguide tracking system 100 can emit a series of acoustic wave pulses via the speaker or transducer of the transmitter 300 (see Figure 3 ). The microphone of the receiver 301 can then "listen" to the characteristics of the returning acoustic signal, such as the echo time between the time of the transmitted pulse and the time when the pulse echo returns, the length of the "tail" (the length of the pulse decay time), and / or other changing harmonic characteristics, such as the attenuation of a portion of the total acoustic spectrum, or the modification of other acoustic characteristics. In a preferred embodiment, the transmitted signal is an acoustic signal in the frequency range that humans can hear (as opposed to an ultrasonic signal). There are several reasons for not using ultrasonic frequencies. First, the disclosed catheter tracking system will have the ability to track catheters, which can be, for example, catheters over 100 feet in length, which is far beyond the relatively short measurement range of ultrasonic sensor-based measurement systems. Second, the disclosed system provides an audible signal that a user can easily determine from which catheter the sound is emanating. During the transmission of the transmitter 300, the microphone of the receiver 301 can be temporarily muted, and after a time interval when the sound stops transmitting, the microphone of the receiver 301 can be unmuted to receive the return echo(s).

[0036] The characteristics of the transmitted and received sound waves (eg, audio signals) can be compared by various commonly used methods, such as by a method that can be built into the acoustic waveguide tracking system device body 101 (see Figure 1-Figure 3) in the audio spectrum analyzer 302. For example, the spectrum analyzer 302 can use the return audio pulse increment (via echolocation) at sea level (at standard temperature and pressure) known to be approximately 340 meters per second to determine the total travel (round trip) timing interval (and therefore distance), the time for the acoustic characteristics to degrade, etc. to determine a rough catheter length calculation for the catheter of interest. The estimated length 201 of the catheter can be displayed on the reader 200 (see Figure 2 ).

[0037] According to one embodiment, once the estimated length 201 of the conduit is determined, the estimated conduit length 201 obtained can be used as a tool to limit the search distance or search radius from the proximal end of the conduit, so that the estimated conduit length 201 can be determined and displayed, and a search for the conduit terminal located within the search distance of the adjacent position can be performed. In other words, a search can be performed from the starting point of the pipeline with an arc equivalent to the estimated conduit length 201 to find a suitable machine room, cabinet, etc., where the distal end or terminal of the conduit can be found.

[0038] According to one embodiment, the acoustic waveguide tracking system 100 can be switched between an audible presence or "tracking" mode 204 or a "length determination" mode 203 via a switch 202 (see Figure 2 ). In operation, the seek mode 204 may utilize a combination of sound waves / audio frequencies (or alternating audio frequencies), pulse repetition rates, and audio rhythms that are designed to be very unique and different from sounds commonly heard in daily life. Sounds such as "white noise" may be used in the "length" 203 mode or the "track" mode 204. The audio frequency and / or characteristic selection may also be automatically selected based on a particular catheter size and / or a judged estimated catheter length to maximize the perceived audio level at the opposite end or distal end of the catheter.

[0039] Since conduits of different diameters have different resonant lengths and subsequent effects on acoustic frequency characteristics, another embodiment of the acoustic waveguide tracking system 100 may have adjustable spectral range and pulse repetition rate to optimize its use with respect to a particular conduit size, similar to how organ pipes are adjusted to allow the pipes to "speak" (resonate) properly. Since the acoustic waveguide tracker 100 always has access to one end of the conduit, the conduit size can be easily determined, as disclosed above, and the appropriate transmitted acoustic wave adjustment settings made automatically or manually.

[0040] Once the search radius arc is known, the user then need only visit those locations that are within and covered by the search arc and listen for the unique emission sound(s). If there is no sound at a particular location (but the system has determined that the remote is on), then the searcher can immediately proceed to the next location rather than wasting time by further inspecting the duct at that location to identify a particular duct that does not present a unique, distinct sound at that location. Furthermore, often ducts may begin from a common starting point, but terminate, for example, on different floors of a building. By knowing the approximate or estimated length of the duct, if all matching arc search locations on a floor have been searched and no sound is present, then the point at which the floor-to-floor measurement is subtracted from the total estimated duct length can then be determined and searched on adjacent floor(s) in the same manner as before. This length subtraction process can then be repeated until the remote of the duct is found.

[0041] It is expected that the acoustic waveguide tracer will be particularly beneficial and will save labor in a number of ways: First, the acoustic waveguide tracer and locating process can optionally be completed by just one person, compared to the traditional requirement of two people (although more than one person will certainly speed up the acoustic waveguide tracing process as well). Second, this will make locating a waveguide within an identified area much easier to accomplish, as the need to further search an entire section of a room, area, etc. can be immediately eliminated.

[0042] On the other hand, Figure 4 As shown, an acoustic waveguide tracking system 400 can be provided. The system 400 can be sized to loosely "slip fit" an appropriately sized unit 400 within an empty electrical conduit or pipe. In addition, the system 400 can be configured to attach to a flexible conduit wire feeder 401, such as a common electrical conduit "snake" tool. The snake tool, i.e., the flexible conduit wire feeder 401, can be used to push an appropriately sized acoustic waveguide tracking system 400 through a conduit 404 so as to allow the acoustic waveguide tracking system 400 to be placed closer to the distal end or terminal of the conduit. Inside the conduit, the acoustic waveguide tracking system 400 can actively emit or emit a unique tone 402. According to a particular embodiment, the system 400 may include only an acoustic wave transmitter sized to fit inside the conduit. The system 400 will be particularly suitable for use with vertical conduits, where gravity will assist in the conduit wire feeding process.

[0043] According to certain aspects, a method for tracking a catheter comprises: transmitting an acoustic signal from a proximal end of the catheter along an interior length of an empty catheter; receiving an acoustic return signal at the proximal end of the catheter; and analyzing the acoustic return signal to determine an estimated length of the catheter. The acoustic signal may be an audio frequency signal and / or a near-audio frequency signal. According to certain embodiments, the analyzing step may include determining an estimated length of the catheter based on one or more differences between the acoustic transmit signal and the acoustic return signal. For example, the analyzing step may include determining an estimated length of the catheter based on: a delay between the time of a transmit pulse and the time of a return echo pulse; the time for the transmit pulse to decay to a predetermined level; a change in harmonic characteristics; and / or an attenuation of a portion of the total frequency spectrum of the acoustic transmit signal.

[0044] According to other embodiments, the step of transmitting a signal may include: transmitting an audio signal having a pulse signal; transmitting a continuous audio signal having a single frequency; transmitting a continuous audio signal having a multi-frequency extension; transmitting an audio signal having a first spectral bandwidth; transmitting an audio signal having a first pulse repetition rate; and / or transmitting a signal having a first pulse frequency characteristic; According to another embodiment, the transmitting step may include transmitting a first signal having a first spectral bandwidth, a first pulse repetition rate, and / or a first pulse frequency characteristic, and then transmitting a second signal having a second spectral bandwidth, a second pulse repetition rate, and / or a second pulse frequency characteristic. According to another embodiment, the transmitting step may include transmitting a "white noise" sound audio along the length of the catheter. Since "white noise" covers a wide range of audio frequencies with uniform intensity, for example, all frequencies have the same intensity, it is particularly suitable for determining the attenuation of a specific frequency audio relative to the length of the catheter.

[0045] According to another aspect, the method of tracking a catheter may further include automatically determining an inner diameter of the catheter. In addition, the transmitting step may include transmitting a first signal when the catheter has a first inner diameter, and transmitting a second signal when the catheter has a second inner diameter.

[0046] refer to Figure 5 , a flow chart is shown that illustrates an exemplary method of using the acoustic waveguide tracking system 100. In step 501, the acoustic waveguide tracking system 100 is associated with a catheter, for example, by inserting the adapter 106 into the proximal end of an empty catheter. In step 501, the acoustic waveguide tracking system 100 is enabled via the switch 102. In step 502, a mode of the acoustic waveguide tracking system 100 is selected. The mode may be selected as "track" or "length" via the switch 202.

[0047] If the "length" mode is selected, the acoustic waveguide tracking system 100 proceeds to step 503. In steps 505 and 506, the size of the conduit is determined (determined by the user or automatically, as disclosed above). In step 504, the switch 104 is used to select whether to manually determine the size of the conduit in step 506 or automatically determine the size of the conduit in step 505. Once the size of the conduit is determined, the transmitter 300 can transmit an audio signal, the receiver 301 can receive the audio return signal, and the spectrum analyzer 302 can determine the estimated length 201 of the conduit in step 507 or step 508.

[0048] After the length of the catheter has been determined, the mode of the acoustic waveguide tracking system 100 may be switched to a "tracking" or "locating" mode (via switch 202) in step 502. In step 510, the transmitter 300 may transmit a signal that is distinct from any background noise to facilitate the user to locate the distal end of the catheter by auditory means.

[0049] While the invention has been shown and described with respect to particular embodiments of the invention, it will be understood by those skilled in the art that various modifications may be made without departing from the spirit and scope of the invention.

Claims

1. An acoustic waveguide tracking system, characterized in that: include: an audio transmitter configured to transmit an audio signal from a proximal end of the catheter along an empty interior length of the catheter; an audio receiver configured to receive an audio return signal at the proximal end of the catheter; as well as An audio spectrum analyzer is configured to analyze the audio return signal to determine the distal position of the catheter.

2. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio spectrum analyzer is configured to use the audio return signal to determine an estimated length of the catheter.

3. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio spectrum analyzer determines an estimated length of the pipe based on one or more differences between the acoustic transmit signal and the acoustic return signal.

4. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio spectrum analyzer determines the estimated length of the catheter based on the following factors: the delay between the time of the transmitted pulse and the time of the returned echo pulse; the time for the transmitted pulse to decay to a predetermined level; the change of harmonic characteristics; and / or the attenuation of a portion of the total spectrum of the audio transmission signal.

5. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio transmitter is configured to pulse the audio transmission signal.

6. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio transmitter is configured to continuously transmit an audio transmission signal at a single frequency.

7. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio transmitter is configured to transmit an audio transmission signal including a multi-frequency extension.

8. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio transmitter is configured to transmit a first audio transmission signal having a first spectrum bandwidth, a first pulse repetition rate and / or a first pulse frequency characteristic.

9. The acoustic waveguide tracking system according to claim 1, characterized in that: The audio transmitter is configured to transmit a first audio transmission having a first spectral bandwidth, a first pulse repetition rate and / or a first pulse frequency characteristic; and wherein the audio transmitter is configured to transmit a second audio transmission signal having a second spectral bandwidth, a second pulse repetition rate and / or a second pulse frequency characteristic.

10. The acoustic waveguide tracking system according to claim 1, characterized in that: The acoustic waveguide tracking system is configured to be at least partially inserted into the proximal end of the catheter.

11. The acoustic waveguide tracking system according to claim 1, characterized in that: The acoustic waveguide tracking system is configured to automatically determine the inner diameter of the guide tube.

12. The acoustic waveguide tracking system according to claim 1, characterized in that: The acoustic waveguide tracker is configured to transmit a first acoustic transmit signal when the conduit has a first inner diameter and to transmit a second acoustic transmit signal when the conduit has a second inner diameter.

13. The acoustic waveguide tracking system according to claim 1, characterized in that: The acoustic waveguide tracking system is configured to operate in a search mode, wherein acoustic waves distinguishable from white noise are transmitted along the length of the conduit for manual detection by a user.

14. The acoustic waveguide tracking system according to claim 1, characterized in that: The acoustic waveguide tracking system is configured to be partially or fully inserted into the catheter, thereby allowing distal advancement along the interior of the catheter.

15. A method for tracking a catheter, comprising: a transmitting step, wherein an acoustic transmission signal is transmitted from the proximal end of the catheter along the empty interior length of the catheter; a receiving step, wherein an acoustic wave return signal is received at the proximal end of the catheter; and An analysis step wherein the acoustic return signal is used to determine an estimated length of the catheter.

16. The method for tracking a catheter according to claim 15, characterized in that: The analyzing step includes determining an estimated length of the pipe based on one or more differences between the acoustic transmit signal and the acoustic return signal.

17. The method for tracking a catheter according to claim 15, characterized in that: The analyzing step includes determining an estimated length of the catheter based on: a delay between the time of a transmit pulse and the time of a return echo pulse; the time it takes for a transmit pulse to decay to a predetermined level; changes in harmonic characteristics; and / or attenuation of a portion of the overall spectrum of the acoustic transmit signal.

18. The method for tracking a catheter according to claim 15, characterized in that: The transmitting step includes transmitting a signal having a pulse signal.

19. The method for tracking a catheter according to claim 15, characterized in that: The transmitting step includes transmitting a continuous audio signal having a single frequency.

20. The method for tracking a catheter according to claim 15, characterized in that: The transmitting step includes transmitting a continuous audio signal having a multi-frequency extension.

21. The method for tracking a catheter according to claim 15, characterized in that: The transmitting step includes transmitting a signal having a first spectral bandwidth, a first pulse repetition rate and / or a first pulse frequency characteristic.

22. The method for tracking a catheter according to claim 15, characterized in that: The transmitting step includes transmitting a signal having a first spectral bandwidth, a first pulse repetition rate and / or a first pulse frequency characteristic, and transmitting a second signal having a second spectral bandwidth, a second pulse repetition rate and / or a second pulse frequency characteristic.

23. The method for tracking a catheter according to claim 15, characterized in that: Further comprising automatically determining the inner diameter of the catheter.

24. The method for tracking a catheter according to claim 15, characterized in that: The transmitting step includes transmitting a first signal when the catheter has a first inner diameter, and transmitting a second signal when the catheter has a second inner diameter.

25. The method for tracking a catheter according to claim 15, characterized in that: Further comprising emitting white noise along the length of the conduit.

26. An acoustic waveguide tracking system, characterized in that: include: The audio transmitter is configured to transmit an audio signal along an interior length of a hollow conduit, wherein the audio transmitter is configured to be mounted within the hollow conduit and further configured to be attached to an end of a flexible conduit wire feeder.

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