Energy transmission device and medical system

Abstract

Provided are an energy transmission device and a medical system that make it possible to more accurately estimate the energy of a wave emitted from an energy emission unit. An energy transmission device (100) comprises: a wave source (110) capable of generating a wave at a predetermined frequency; a transmission path (120) for transmitting the wave; an energy emission unit (130) for emitting, to the surroundings, the wave transmitted via the transmission path; a frequency adjustment unit (140) capable of adjusting the frequency of the wave; an information acquisition unit (150) for acquiring reflected wave information pertaining to the amplitude and the phase of a composite wave obtained by combining a plurality of reflected waves generated due to reflection of the wave transmitted via the transmission path; and a computation unit (160) for computing the amplitude and the phase of the composite wave on the basis of the reflected wave information, and computing the magnitude of the energy of the wave emitted from the energy emission unit on the basis of the amplitude and the phase of the composite wave.

Description

Energy transmission device and medical system

[0001] The present invention relates to an energy delivery device and a medical system.

[0002] Conventionally, development of devices utilizing waves having a predetermined frequency has been progressing in various industrial fields. For example, Patent Document 1 listed below proposes the use of microwaves as waves for imparting energy to a predetermined treatment site in a living body.

[0003] In the above-mentioned wave-based devices, it is important to check and adjust the output energy from the energy radiating unit (e.g., antenna element) that emits energy. In particular, when radiating energy inside a living body, it is desirable that the difference between the set radiated energy and the actually radiated energy be as small as possible in consideration of the effects on the living body, so it is required to more strictly control the energy radiated from the energy radiating unit.

[0004] JP 2022-091850 A

[0005] Waves generated by a wave source (e.g., a microwave oscillation source) produce reflected waves at various points along the transmission path (e.g., a coaxial cable or various electrical connectors) connecting the wave source and the energy radiator, and these reflected waves then interfere with each other to produce a composite wave.

[0006] The inventors of the present invention have discovered that by analyzing information regarding the amplitude and phase of the composite wave generated as described above, it is possible to more accurately estimate the energy of the waves radiated from the energy radiating portion.

[0007] An object of the present invention is to provide an energy transmission device and a medical system that are capable of more accurately estimating the energy of waves radiated from an energy radiating portion.

[0008] The energy transmission device of the present disclosure includes a wave source capable of generating waves of a predetermined frequency, a transmission path for transmitting the waves, an energy emission unit for emitting the waves transmitted via the transmission path to the surroundings, a frequency adjustment unit for adjusting the frequency of the waves, an information acquisition unit for acquiring reflected wave information regarding the amplitude and phase of a composite wave formed by combining multiple reflected waves generated by reflecting the waves transmitted via the transmission path, and a calculation unit for calculating the amplitude and phase of the composite wave based on the reflected wave information, and for calculating the magnitude of the energy of the waves radiated from the energy emission unit based on the amplitude and phase of the composite wave.

[0009] According to the present disclosure, it is possible to more accurately confirm the wave energy radiated from the energy radiating portion.

[0010] 1 is a diagram illustrating a schematic diagram of an energy transmission device and a medical system according to an embodiment.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope or the meaning of terms described in the claims. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions. Also, the range "X to Y" shown in this specification means "greater than or equal to X and less than or equal to Y."

[0012] FIG. 1 is a diagram schematically illustrating an energy transmission device and a medical system according to an embodiment.

[0013] As shown in FIG. 1, the energy transmission device 100 includes a wave source 110 capable of generating waves of a predetermined frequency, a transmission path 120 for transmitting the waves, an energy radiation unit 130 for emitting the waves transmitted via the transmission path 120 to the surrounding area, a frequency adjustment unit 140 for adjusting the frequency of the waves, an information acquisition unit 150 for acquiring reflected wave information regarding the amplitude and phase of a composite wave formed by combining multiple reflected waves generated by reflecting the waves transmitted via the transmission path 120, and a calculation unit 160 for calculating the amplitude and phase of the composite wave based on the reflected wave information, and for calculating the magnitude of the energy of the waves radiated from the energy radiation unit 130 based on the amplitude and phase of the composite wave.

[0014] In this embodiment, the energy transmission device 100 and the catheter 200 constitute a predetermined medical system 10 .

[0015] The waves generated by the wave source 110 are not particularly limited as long as they have wave properties and a predetermined energy. Examples of the waves include electromagnetic waves including microwaves and sound waves. In this embodiment, an example will be described in which microwaves generated by the wave source 110 are radiated from the energy radiating unit 130.

[0016] The wave source 110 can be configured as a known microwave source configured to be able to generate a predetermined wave.

[0017] The transmission path 120 can be configured with various members capable of transmitting the waves generated by the wave source 110 to the energy radiating unit 130. In this embodiment, the transmission path 120 is formed by a plurality of coaxial cables 121 a, 121 b, and 121 b electrically connected to the wave source 110 and a plurality of connectors 122 a and 122 b.

[0018] The coaxial cable 121a is directly connected to the wave source 110. The coaxial cable 121b is connected to the coaxial cable 121a via the connector 122a. The coaxial cable 121c is connected to the coaxial cable 121c via the connector 121b. The coaxial cable 121 can be disposed inside the catheter 200, and the energy emitting unit 130 can be disposed near the tip of the catheter 200.

[0019] The catheter 200 can be configured as, for example, an ablation catheter that radiates energy emitted from the energy radiating unit 130 to a predetermined part of the body. When the catheter 200 is configured in this manner, the energy radiating unit 130 can be configured with an antenna element capable of radiating microwaves.

[0020] The frequency adjusting unit 140, the information acquiring unit 150, and the calculating unit 160 can be incorporated as part of the device configuration of the wave source 110.

[0021] The wave source 110 has a control unit (not shown) that controls all operations performed by the wave source 110 and all components of the device. The control unit can be configured with a known microcomputer including a CPU, RAM, ROM, etc. The CPU of the control unit reads various programs pre-stored in the ROM into the RAM and executes them, thereby executing predetermined processing related to this embodiment. The control unit also has a memory unit that stores various setting information and control programs, a calculation unit 160 that performs various calculations, and a function as a determination unit that determines the operating state of the energy emission unit 130 based on the calculation results by the calculation unit 160.

[0022] The information acquiring unit 150 has a wattmeter 151 that measures the amplitude of the composite wave and a phase detector 152 that measures the phase of the composite wave. In this embodiment, the information acquiring unit 150 is configured to include a voltmeter 153 that can measure the voltage of the composite wave, in addition to the wattmeter 151 and the phase detector 152. The information acquiring unit 150 does not necessarily have to include the voltmeter 153.

[0023] The medical system 10 and the energy transmission device 100 shown in FIG. 1 can solve the problems described below.

[0024] As shown in Figure 1, in a medical system 10 (ablation system) in which a wave source 110 (microwave transmission source) and multiple coaxial cables 121a, 121b, and 121c are connected in series to enable wave transmission, and an energy radiating unit 130 (microwave antenna) is implemented on the tip side (tip side of the catheter 200), the waves (microwaves) transmitted from the wave source 110 travel to the energy radiating unit 130 while attenuating in each of the coaxial cables 121a, 121b, and 121c.

[0025] Most of the energy of the wave source that reaches each of the connectors 122a and 122b is transmitted through each of the connectors 122a and 122b, while a small amount of energy is reflected by each of the connectors 122a and 122b.

[0026] Most of the energy that reaches the energy radiating section 130 without being reflected is radiated as microwaves toward the space around the energy radiating section 130. However, part of the energy that reaches the energy radiating section 130 is also reflected by the energy radiating section 130.

[0027] When using microwave energy emitted from the tip of the medical system 10 of this embodiment (the energy emitting unit 130 located near the tip of the catheter 200) for ablation treatment, it is important to more accurately confirm the energy radiated from the energy emitting unit 130 for the following reasons.

[0028] For example, if the energy radiating unit 130 is manufactured as an antenna element, variations in the actual energy emitted from the antenna element may occur due to individual differences in the manufacturing process of the antenna element, or unexpected degradation of the antenna performance due to damage during transportation or use may occur, which may result in a situation where the energy radiated from the antenna element does not reach the predetermined site (treatment site) of the living body. In medical settings where the catheter 200 is used, in order to quickly detect such situations, it is necessary to accurately grasp the energy radiated from the energy radiating unit 130. However, the following points arise in accurately grasping the energy radiated from the energy radiating unit 130.

[0029] Generally, the wave source 110 has a function for measuring the power of waves (microwaves) reflected up to the wave source 110. Therefore, the medical system 10 can detect the increase or decrease in the power of the waves reflected up to the wave source 110 by using the above function provided in the wave source 110. Therefore, the energy transmission device 100 can also evaluate the degradation of the antenna performance based on the increase or decrease in the power of the waves detected by the wave source 110.

[0030] For example, when evaluating performance using the above system, it is possible to set predetermined thresholds such as "when the energy radiating unit 130 is functioning normally, the energy reflected from the energy radiating unit 130 to the wave source 110 is approximately 3% of the incident energy (energy supplied from the wave source 110 to the coaxial cable 121a)," "when the energy radiating unit 130 is faulty, this value is approximately 20%," and "when the system is completely malfunctioning (e.g., the coaxial cable is broken), this value is 100%." ​​Furthermore, when thresholds are set in this manner, the system can be configured to determine that "a state in which the reflected wave measured by the wave source 110 increases by 20% or more of the incident energy" has occurred. However, the reflected wave measured by the wave source 110 is attenuated in the coaxial cables 121a, 121b, and 121c while returning from the energy radiating unit 130 to the wave source 110. Therefore, the absolute value of the energy of the reflected wave detected by the wave source 110 is smaller than the actual value that should be measured by the energy radiating unit 130 located at the tip of the system due to the influence of attenuation in the coaxial cables 121a, 121b, and 121c.

[0031] Furthermore, the energy of the reflected wave detected by the wave source 110 is a composite wave of the reflected wave generated by each connector 122a, 122b (hereinafter referred to as the "connector-side reflected wave") and the reflected wave generated by the energy radiating unit 130 (hereinafter referred to as the "antenna-side reflected wave"). Although the connector-side reflected wave is usually very small, since the reflection position is closer to the wave source 110, its attenuation before reaching the wave source 110 is relatively small. Therefore, the connector-side reflected wave makes a relatively large contribution to the composite wave detected by the wave source 110.

[0032] Furthermore, in the medical system 10 (treatment system) of this embodiment, the catheter 200 is inserted into a body cavity such as a blood vessel, and therefore, to prevent infection, the parts that come into contact with the patient must be provided as disposables. For example, the parts located distal to the connector 122a (the side introduced into the patient's body) are replaced with different parts for each patient. In other words, different components distal to the connector 122a are used each time a treatment or procedure is performed. Therefore, the lengths of the coaxial cables 121b and 121c included in the medical system 10 include variations due to tolerances. Therefore, among the reflected waves from the connector 121a, the reflected waves from the connector 121b, and the reflected waves from the energy emitting unit 130, the reflected waves from the connector 121b and the energy emitting unit 130 exhibit random phase shifts due to path length tolerances. Therefore, the amplitude of the composite wave measured by the wave source 110 varies significantly each time a different coaxial cable is connected.

[0033] As described above, the normality / failure of the energy radiating unit 130 results in a difference in the reflected wave power measured by the wave source 110, but this difference is very small at the time of detection by the wave source 110. Therefore, in the reflected wave power detected by the wave source 110, the reflected wave power from the energy radiating unit 130 is submerged in variations due to phase shifts of the reflected waves from each of the connectors 121 a, 121 b. For these reasons, it can be said that it is extremely difficult to detect a faulty state of the energy radiating unit 130 by setting a uniform cutoff value for the reflected wave power detected by the wave source 110.

[0034] As means for solving the above-mentioned problems, there are methods that can be considered, such as a method of rejecting antennas equipped with coaxial cables having a path length that increases the amplitude of the composite wave in advance, or a method of measuring the characteristics of each antenna during manufacture, recording the measurement results, and canceling the effect of phase shift. However, both of these methods reduce product yield and increase manufacturing costs, and even if they can detect a performance degradation beyond a certain level, they cannot detect the amount of energy actually radiated from the energy radiating unit.

[0035] In this embodiment, in response to the above-described problems, it is possible to provide a system that can more accurately grasp (estimate) the energy of waves (microwaves) radiated from the energy radiating unit 130 through calculation (processing) by the calculation unit 160. This embodiment is useful in that it can detect changes in the energy of waves radiated from the energy radiating unit 130 and make decisions such as appropriately adjusting the magnitude of the energy to be output or, in some cases, urgently stopping the radiation of energy, without significantly increasing costs.

[0036] To solve the above problem, specifically, the calculation unit 160 performs the following process.

[0037] When the frequency of the wave is changed by the frequency adjustment unit 140, the calculation unit 160 calculates the magnitude of the energy radiated from the energy radiating unit 130 by taking advantage of the fact that the phase fluctuation of each reflected wave (the reflected wave generated in each part of the medical system 10) in response to the change in frequency depends on the wavelength and propagation distance in the transmission path to each reflection position where each reflected wave is generated (e.g., each connector 122a, 122b, the energy radiating unit 130, etc.).

[0038] Furthermore, instead of or in addition to the above processing, the calculation unit 160 separates the composite wave into individual reflected components by utilizing the fact that when the frequency of the wave is changed by the frequency adjustment unit 140, the speed of change in the phase of each reflected wave with respect to the change in frequency depends on the wavelength and propagation distance in the transmission path to each reflection position where each reflected wave is generated, thereby calculating the magnitude of the energy radiated from the energy radiating unit 100. More specifically, the calculation unit 160 separates the composite wave into individual reflected components, calculates the propagation distance of each reflected component, and further identifies the reflected component from the energy radiating unit 130 based on the propagation distance to the reflection position, thereby calculating the magnitude of the energy radiated from the energy radiating unit 130.

[0039] An example of the calculation method performed by the calculation unit 160 will be described below.

[0040] Consider the case where the respective reflection positions at the connectors 122a and 122b and the energy radiating unit 130 (antenna element) are fixed (unmoving). The reflected waves of the respective voltages can be expressed in complex numbers as shown in the following equations, excluding the time-varying terms.

[0041]

[0042] In the above formula, A １ , A ２ , A ３ are the amplitudes of the respective reflected waves, and L １ , L ２ , L ３ is the distance from the wave source 110 to each reflection location, and λ is the wavelength.

[0043] Furthermore, λ=c / f, and wavelength is inversely proportional to frequency (c is the speed of light in each of the coaxial cables 121a, 121b, and 121c, and f is frequency).

[0044] Also, the observed signal p ａｌｌ (λ) is p ａｌｌ (λ) = p １ (λ) + p ２ (λ) + p ３ (λ).

[0045] When t = const. and x = 1 / λ on the complex plane, each reflected component rotates with a different amplitude and rotation speed as x increases. Furthermore, the observed signal pall, which is the sum of these reflected components, rotates while tracing a complex trajectory on the complex plane.

[0046] When the microwave source of the wave source 110 is a solid-state type, the transmission frequency f can be swept within a certain range. In particular, the range of f = 2400 to 2500 MHz is an ISM frequency band, which is an advantageous frequency band from the viewpoint of electromagnetic compatibility.

[0047] The propagation velocity c in the coaxial cable is 3 × 10 ８ m / s, and L １ = 2.0 m, L ２ = 3.0 m, L ３ When the frequency is changed from 2400 to 2500 MHz, p１ , p ２ , p ３ The phases of the two change to 480 deg, 720 deg, and 888 deg, respectively.

[0048] That is, when the frequency is changed between 2400 and 2500 MHz, p １ , p ２ , p ３ Since each of these generates a phase shift of at least one period on the complex plane, the observed P ａｌｌ reflects the characteristics of each component well.

[0049] Since the function form is known, the P ａｌｌ For the amplitude and phase fluctuation data of each parameter A １ , A ２ , A ３、 L １ , L ２ , L ３ By fitting the individual signal components to p １ , p ２ , p ３ can be separated into

[0050] Since the magnitude of the incident wave and the attenuation in each of the coaxial cables 121a, 121b, and 121c are known, it is possible to calculate the power incident on the energy emitting unit 130. The calculation unit 160 can further estimate the actual energy emitted from the energy emitting unit 130 by calculating the difference between the power of the reflected wave component at the energy emitting unit 130 separated by the above procedure and the incident power.

[0051] Therefore, the energy transmission device 100 and the medical system 10 can preset the magnitude of the desired energy emitted from the energy emitting unit 130, automatically increase or decrease the incident energy from the wave source 110 so that the energy emitted does not deviate from the set range, and if the range of deviation is large, determine that a malfunction has occurred and perform an emergency stop on the waves (microwaves). As a result, this embodiment can provide a medical system 10 with higher safety.

[0052] REFERENCE SIGNS LIST 10 Medical system 100 Energy transmission device 110 Wave source 120 Transmission path 121a Coaxial cable 121b Coaxial cable 121c Coaxial cable 122a Connector 122b Connector 130 Energy radiation unit 140 Frequency adjustment unit 150 Information acquisition unit 151 Power meter 152 Phase detector 153 Voltmeter 160 Calculation unit 200 Catheter

Claims

1. An energy transmission device having: a wave source capable of generating waves of a predetermined frequency; a transmission path for transmitting the waves; an energy emission unit for emitting the waves transmitted via the transmission path to the surroundings; a frequency adjustment unit for adjusting the frequency of the waves; an information acquisition unit for acquiring reflected wave information regarding the amplitude and phase of a composite wave formed by combining multiple reflected waves generated by reflecting the waves transmitted via the transmission path; and a calculation unit for calculating the amplitude and phase of the composite wave based on the reflected wave information, and for calculating the magnitude of energy of the waves radiated from the energy emission unit based on the amplitude and phase of the composite wave.

2. The energy transmission device of claim 1, wherein the calculation unit calculates the magnitude of the energy radiated from the energy radiating unit by utilizing the fact that when the frequency of the wave is changed by the frequency adjustment unit, the fluctuation in phase of each of the reflected waves in response to the change in frequency depends on the wavelength and propagation distance in the transmission path to each reflection point where each of the reflected waves is generated.

3. An energy transmission device as described in claim 1 or claim 2, wherein the calculation unit calculates the magnitude of the energy radiated from the energy radiating unit by separating the composite wave into individual reflected components, utilizing the fact that when the frequency of the wave is changed by the frequency adjustment unit, the speed of phase fluctuation of each of the reflected waves in response to the change in frequency depends on the wavelength and propagation distance in the transmission path to each reflection point where each of the reflected waves is generated.

4. The energy transmission device of claim 3, wherein the calculation unit separates the composite wave into individual reflected components, calculates the propagation distance of each reflected component, and further identifies the reflected component from the energy radiating unit based on the propagation distance to the reflection point, thereby calculating the magnitude of the energy radiated from the energy radiating unit.

5. The energy transmission device of claim 1, wherein the wave source has a microwave oscillation source capable of generating microwaves as the wave motion, the energy emitting unit has an antenna element capable of emitting the microwaves, the transmission path includes a coaxial cable and a plurality of connector units connecting the microwave oscillation source and the energy emitting unit so as to be capable of transmitting the wave motion, and the information acquisition unit has a power meter that measures the amplitude and a phase detector that measures the phase.

6. A medical system comprising: an energy transmission device according to any one of claims 1 to 5; and a medical device comprising a catheter having the energy emission portion disposed at its tip.

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