JP2006166958A - In vivo medical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in vivo medial device which improves the communication performance by extending the communication range along with the longer life of the battery by restricting the transmission power of the wireless circuits in the communication with a wireless communication devices outside the living body. <P>SOLUTION: In the in vivo medial device (heart rhythm managing device) 100 for medical care which is implanted in vivo or inserted into the celom to detect the biomedical information, a magnetic field mode antenna element (loop element) 101 with a less worsened efficiency in vivo as compared with the electric field mode antenna element is provided for the communication with the wireless communication devices outside the living body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-vivo medical device that is implanted in a living body or inserted into a body cavity to detect biological information and perform medical treatment, and in particular, transmits biological information and the like to an in vitro wireless communication device, Alternatively, the present invention relates to an antenna of an in-vivo medical device for receiving data for controlling the in-vivo medical device from the in-vitro wireless communication device, that is, for communicating with the in-vitro wireless communication device.

  Conventionally, as this kind of in-vivo medical device, there existed what was described in patent document 1, for example. FIG. 8 shows a cardiac rhythm management device such as a pacemaker or an implantable defibrillator as a conventional in-vivo medical device described in Patent Document 1. In FIG. 8, the cardiac rhythm management device 801 is implanted in the human body 1 by surgery, monitors the electrical activity of the heart 2 sensed in the heart 2, and detects an abnormality in the electrical activity of the heart 2. In order to correct the rhythm of the heart 2, two lead wires 802 and 803 are provided for applying an electrical stimulation signal to the heart 2 from a pulse generator (not shown). The lead wires 802 and 803 are connected to the in vitro wireless communication device 804. It was the structure operated as a dipole antenna for communication.

  With this configuration, it is not necessary to add a new antenna element only for communication with the in vitro wireless communication device 804, and biological information such as cardiac rhythm information can be transmitted, and the heart sensed within the heart 2 A diagram of two electrical activities, ie an electrogram (abbreviated as EGM), can be obtained in the in vitro wireless communication device 804. Here, the electrogram is different from an electrocardiogram ECG (Electrocardiogram) which is a diagram of the electrical activity of the heart sensed on the skin surface. On the other hand, the program of the cardiac rhythm management device 801 can be rewritten by receiving program data from the in vitro wireless communication device 804.

  Further, for example, there is one described in Patent Document 2. FIG. 9 shows a capsule endoscope as a conventional in-vivo medical device described in Patent Document 2. In FIG. 9, the capsule endoscope 901 is configured to include an imaging element, an imaging light source, a wireless circuit, and an antenna element for communication with the in vitro wireless communication device 902 that are not shown in the figure.

With this configuration, when the capsule endoscope 901 is swallowed by the patient, the esophagus 3, the stomach 4 and the inner wall of the intestine not shown are imaged and transmitted to the in vitro wireless communication device 902 as image data. An image can be obtained with the display device 903 of the wireless communication device 902, and the operation and imaging function of the capsule endoscope 901 can be controlled from the in-vitro wireless communication device 902 to clearly capture a desired object. it can. Further, since the cable necessary for connecting the camera head unit and the external device as in the conventional gastrocamera is unnecessary, it is not necessary to advance and retract the camera head unit and the connection cable in the body cavity. It can eliminate pain.
Japanese Patent Laid-Open No. 4-218171 (FIG. 1) JP 2003-135389 A (FIG. 1)

  However, the dipole antennas 802 and 803 of the cardiac rhythm management device 801 described in Patent Document 1 are electric field mode antenna elements and are placed in a living body which is a lossy dielectric having a relative dielectric constant of about 40 to 60. In this case, the electrical length of the antenna element with respect to the free space is shortened, for example, when it is implanted at a depth of 2 cm from the chest surface, it is shortened to about one fifth, and the resonance frequency greatly changes. There was a problem that appropriate matching circuits were different between the space and the living body. Further, even when the free space and the living body are matched with the wireless circuit, there is a problem that the efficiency is deteriorated by about 20 dB in the living body as compared with the free space. For this reason, it is necessary to bring the antenna element 805 of the in vitro wireless communication device 804 in close proximity to the human body 1 or to increase the transmission power of the wireless circuit in the heart rhythm management device 801 or the in vitro wireless communication device 804. It was.

  Further, in the capsule endoscope 901 described in Patent Document 2, the configuration of the antenna is not specified. In the case of the electric field mode antenna element similar to Patent Document 1, the in-vivo efficiency degradation is remarkable, and the in-vitro wireless communication device 902 and the in-vitro wireless communication device 902 antenna element 904 need to be in close proximity to the human body 1. It was.

  In order to solve the above-described problems, the present invention facilitates impedance matching with a radio circuit in an in-vivo medical device and provides high antenna efficiency. It is possible to provide an in-vivo medical device that suppresses electric power and extends the life of a battery, extends a communication distance, and improves communication performance.

  In order to solve the above-described conventional problems, an in-vivo medical device according to the present invention is an in-vivo medical device that is implanted in a living body or inserted into a body cavity to detect biological information and perform medical treatment. A magnetic field mode antenna element is provided for communication with an external wireless communication device.

  With this configuration, impedance matching with the radio circuit is easy in the in-vivo medical device and high antenna efficiency can be obtained. Therefore, when communicating with the in-vitro radio communication device, the transmission power of the radio circuit is suppressed and the battery life is shortened. The communication distance can be increased and the communication performance can be improved.

  Moreover, you may comprise so that a loop element may be provided as said magnetic field mode antenna element.

  Moreover, you may comprise so that a slot element may be provided as said magnetic field mode antenna element.

  The cardiac rhythm information detected by the cardiac rhythm information detecting means is further provided with cardiac stimulation means for providing an electrical stimulation signal to the heart when the cardiac rhythm information detecting means detects an abnormality. May be configured to include communication means for transmitting to the in vitro wireless communication device.

  Moreover, you may comprise so that the imaging means which images the inside of a body cavity is provided, and the communication means which transmits the image | video in the body cavity imaged by the said imaging means to the said in vitro radio | wireless communication apparatus.

  As described above, according to the in-vivo medical device of the present invention, when communicating with an in-vitro wireless communication device, the transmission power of the wireless circuit is suppressed, the battery life is extended, the communication distance is extended, and the communication performance is improved. An improved in-vivo medical device can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
1 and 2 are a perspective view and a plan view of a cardiac rhythm management device 100 as an in-vivo medical device according to Embodiment 1 of the present invention. FIG. 3 is a diagram illustrating a state in which the heart rhythm management device 100 is implanted in the human body 1. In the following description, the same components as those in FIG.

  In FIG. 1, a lead 109 extending from the cardiac rhythm management device 100 monitors the electrical activity of the heart 2 sensed in the heart 2, and when an abnormality is detected in the electrical activity of the heart 2. In order to correct the rhythm, an electrical stimulation signal is given to the heart 2 from a pulse generator (not shown). The loop element 101 operates as an antenna that transmits / receives data to / from the in vitro wireless communication device 804 and is disposed along the end of the heart rhythm management device 100.

  One end 102 of the loop element 101 is connected to a ground pattern serving as a ground potential on the circuit board 107 on which the wireless circuit 106 is mounted at the ground portion. A tuning circuit (capacitor) 104 is connected to the other end 103 of the loop element 101, and the resonance frequency is set from 401 MHz to 406 MHz. A power feeding unit 105 is installed at a position away from the ground point 102 of the loop element 101 by a predetermined interval (for example, about 10 mm). Thus, the impedance of the power feeding unit 105 is set to 50 ohms, for example, by tapping down the impedance of the loop element 101.

  Next, the configuration of the loop element 101 will be described in detail with reference to FIG. The loop element 101 is formed of, for example, a conductor plate having a thickness of 1 mm that is folded back with a length L1 of 50 mm, a height L2 of 5 mm, and an element width L3 of 5 mm. The distance L4 between the grounding portion (not shown) of the loop element 101 and the tuning circuit connecting portion (not shown) is set to about 5 mm. The loop element 101 is fixed with a distance L5 between the circuit board 107 set to 2 mm. At this time, the loop opening surface of the loop element 101 is orthogonal to the circuit board 107. In general, a ground pattern is disposed on the entire surface of the circuit board 107. Therefore, the loop opening surface of the loop element 101 is orthogonal to the ground pattern, that is, the ground plane. The loop element 101 operates as a minute loop antenna element having a loop length of about 1/10 wavelength or a magnetic field mode antenna element from 401 MHz to 406 MHz, and its operating frequency band is relatively narrow. For example, the bandwidth is about 10 MHz at 400 MHz and about 2% in the specific band.

  Next, a state in which the heart rhythm management device 100 configured as described above is implanted in the human body 1 will be described with reference to FIG. A circuit board (not shown) is substantially parallel to the chest surface, and the opening surface of the loop element 101 is substantially perpendicular to the chest surface. The relative permeability of the human tissue covering the loop element 101 is 1, and the resonance frequency of the loop element 101 which is a magnetic field mode antenna element hardly changes compared to the free space. In addition, the degradation of efficiency is about 10 dB compared to free space, and is much smaller than the degradation of about 20 dB in the electric field mode antenna element.

  For example, as shown in FIG. 4, in order to ensure the communication performance between the cardiac rhythm management device 100 including the loop element 101 as the magnetic field mode antenna element and the in vitro wireless communication device 804, the in vitro wireless communication device 804 is connected to the human body 1. There is no need to be close to. The in-vitro wireless communication device 804 can be installed in a separate room while the patient 1 in which the heart rhythm management device 100 is implanted is lying on the hospital bed 401, and the in-vitro wireless communication device 804 need not be frequently moved. The patient's burden can be reduced.

  As described above, in an in-vivo medical device for implanting in-vivo, detecting bio-information, and performing medical care, by providing a loop element as a magnetic field mode antenna element for communicating with an in-vitro wireless communication device, wireless Impedance matching with the circuit is easy and high antenna efficiency can be obtained, so when communicating with in vitro wireless communication devices, the transmission power of the wireless circuit is suppressed to extend the battery life, extend the communication distance, and communicate The performance can be improved.

  The magnetic field mode antenna element is not limited to the loop element, and may be any antenna that operates in the magnetic field mode, such as a slot element.

  Further, when the housing (not shown) of the heart rhythm management device 100 is a conductive metal such as titanium, the loop element or the slot element may be configured using the conductive metal housing.

  Further, although the case of unbalanced power supply has been described, the same effect can be obtained as balanced power supply.

  In addition, the case where the loop opening surface is arranged so as to be substantially perpendicular to the chest surface in the state of being implanted in the human body 1 has been described. However, the loop opening surface may be arranged substantially parallel to the chest surface. It is desirable not to cover the opening surface with a ground pattern of a circuit board (not shown). Furthermore, it is desirable to set the direction of the loop opening surface in accordance with the characteristics of the antenna of the in vitro wireless communication device.

  Further, although the case of the cardiac rhythm management device 100 as an in-vivo medical device has been described, the biological information is not limited to heart rhythm information, but includes, for example, blood pressure, pulse, body temperature, blood saturated oxygen concentration, muscle relaxation information, and the like. The medical treatment is not limited to providing an electrical stimulation signal to the heart 2 in order to adjust the rhythm of the heart 2.

  Moreover, as information transmitted / received between the in vivo medical device and the in vitro wireless communication device, in addition to the biological information, for example, control information for controlling the operation of the in vivo medical device from the in vitro wireless communication device There is personal information to identify the patient and diagnostic information of the patient.

  Moreover, although the case of the human body 1 as a living body was described, it can be applied to, for example, management of livestock.

(Embodiment 2)
5 and 6 are an exploded perspective view and a plan view of a heart rhythm management device 500 as an in-vivo medical device according to Embodiment 2 of the present invention. In the following description, the same reference numerals are used for the same components as those in the above-described drawings, and the description is omitted.

  In FIG. 5, a slot element 501 operates as an antenna that transmits and receives data to and from an in vitro wireless communication device 804 (shown in FIG. 4). For example, a flat surface 509 of a conductive metal casing 509 such as titanium. Provided in (a).

  Next, the configuration of the slot element 501 will be described in detail with reference to FIGS. The slot element 501 is constituted by a slot having a length L6 of 50 mm and a width L7 of 2 mm. In a state where the heart rhythm management device 500 is assembled, the distance L8 between the circuit board 508 and the slot element 501 is set to about 5 mm and fixed. In the slot element 501, a tuning circuit (capacitor) 502 on the circuit board 508 is connected to a midpoint in the longitudinal direction (L6) via connection pins of the tuning circuit connections 503 and 504, and the tuning circuit connection 503. Are connected to a ground pattern serving as an installation potential on the circuit board 508 on which the wireless circuit 507 is mounted via a ground pin 505 at a position separated from the terminals 504 by a predetermined distance L9 (for example, about 10 mm). The wireless circuit 507 is connected through the pin 506. The connection pins 503 and 504, the ground pin 505, and the power supply pin 506 are elastic conductive metals, and electrical connection with each part of the slot element 501 is ensured by assembling the heart rhythm management device 500. Accordingly, the impedance of the power feeding unit 506 is set to be, for example, 50 ohms. The slot element 501 operates as a minute slot antenna element or magnetic field mode antenna element having a slot length of 1/10 wavelength or less from 401 MHz to 406 MHz, and its operating frequency band is relatively narrow.

  The state in which the heart rhythm management device 500 configured as described above is implanted in the human body 1 is the same as that in FIG. 3, and the slot element 501 that is a magnetic field mode antenna element has almost no change in the resonance frequency compared to free space. In addition, the degradation of efficiency is about 10 dB compared to free space, and is much smaller than the degradation of about 20 dB in the electric field mode antenna element. Therefore, in order to secure the communication performance between the cardiac rhythm management device 500 including the slot element 501 as the magnetic field mode antenna element and the in vitro wireless communication device 804, the in vitro wireless communication device 804 does not need to be close to the human body 1. . For example, as in FIG. 4, the in vitro wireless communication device 804 can be installed in a separate room in a state where the patient 1 who has implanted the cardiac rhythm management device 500 lies on the hospital bed 401. It is not necessary to move frequently and the burden on the patient can be reduced.

  As described above, in an in vivo medical device for implanting in vivo, detecting biological information, and performing medical care, by providing a slot element as a magnetic field mode antenna element for communicating with an in vitro wireless communication device, wireless Impedance matching with the circuit is easy and high antenna efficiency can be obtained, so when communicating with in vitro wireless communication devices, the transmission power of the wireless circuit is suppressed to extend the battery life, extend the communication distance, and communicate The performance can be improved.

  The power supply to the slot element 501 is not limited to unbalance, and the same effect can be obtained as balanced power supply.

  Further, one plane 509 (a) of the conductive metal casing 509 and the other surface may be electrically connected to have the same potential in terms of direct current, that is, the ground potential. An effect is obtained.

  In addition, it is desirable to set the surface on which the slot is formed in the conductive metal housing according to the direction of implantation in the human body 1 and according to the characteristics of the antenna of the in vitro wireless communication device.

(Embodiment 3)
FIG. 7 is a plan view of a capsule endoscope 700 as an in-vivo medical device according to Embodiment 2 of the present invention. In the following description, the same components as those in FIG.

  In FIG. 7, the imaging device 708 built in the capsule endoscope 700 allows the patient to swallow the capsule endoscope 700, thereby causing the esophagus 3, the stomach 4 (shown in FIG. 9), and an intestine not shown. The inner wall is imaged. The loop element 701 operates as an antenna that transmits and receives data to and from the in vitro wireless communication device 902, and is disposed along the outer periphery of the capsule endoscope 700.

  The loop element 701 has the same configuration as the loop element 101 described above, and one end 702 of the loop element 701 is connected to a ground pattern serving as a ground potential on the circuit board 707 on which the wireless circuit 706 is mounted in the ground portion. A tuning circuit (capacitor) 704 is connected to the other end (tuning circuit connection portion) 703 of the loop element 701, and the resonance frequency is set from 401 MHz to 406 MHz. The tuning circuit 704 may be mounted on the circuit board 707. A power feeding unit 705 is installed at a position away from the ground point 702 of the loop element 701 by a predetermined interval. Accordingly, the impedance of the power feeding unit 705 is set to, for example, 50 ohms by tapping down the impedance of the loop element 701. The loop length of the loop element 701 is about half that of the loop element 101 described above, and operates from 401 MHz to 406 MHz as a minute loop antenna element or magnetic field mode antenna element having a loop length of 1/10 wavelength or less.

  A state where the capsule endoscope 700 configured as described above is inserted into the body cavity by swallowing the patient will be described. The relative permeability of the human tissue covering the loop element 701 is 1, and the resonance frequency of the loop element 701 that is a magnetic field mode antenna element hardly changes compared to the free space. Moreover, the degradation of efficiency is about 10 dB compared with free space, and is much smaller than an electric field mode antenna element. Therefore, in order to ensure the communication performance between the capsule endoscope 700 including the loop element 701 as a magnetic field mode antenna element and the in vitro wireless communication device 902, it is necessary to bring the in vitro wireless communication device 902 close to the human body 1. Absent. For example, as in FIG. 4, the in vitro wireless communication device 804 can be installed in a separate room while the patient 1 swallowing the capsule endoscope 700 lies on the hospital bed 401, and the in vitro wireless communication device 902 It is not necessary to move frequently, and the burden on the patient can be reduced.

  As described above, an in-vivo medical device that is inserted into a body cavity to detect biological information and perform medical treatment, includes a magnetic field mode antenna element for communicating with an in-vitro wireless communication device, and Impedance matching and high antenna efficiency can be obtained, so when communicating with in-vitro wireless communication devices, the transmission power of the wireless circuit is suppressed, the battery life is extended, the communication distance is extended, and the communication performance is improved. Can be improved.

  The magnetic field mode antenna element is not limited to the loop element, and may be any antenna that operates in the magnetic field mode, such as a slot element.

  Further, when the casing 709 of the capsule endoscope 700 is a conductive metal such as titanium, a loop element or a slot element may be configured using the conductive metal casing.

  Further, although the case of unbalanced power supply has been described, the same effect can be obtained as balanced power supply.

  In addition, it is desirable to set the direction of the loop opening surface in the capsule endoscope 700 so as to obtain a wide loop opening area from the viewpoint of obtaining high antenna efficiency.

  The in-vivo medical device provided with the magnetic field mode antenna element according to the present invention suppresses the transmission power of the wireless circuit and extends the battery life and extends the communication distance when communicating with the in-vitro wireless communication device. Therefore, it is useful for cardiac rhythm management devices such as pacemakers and implantable cardioverter defibrillators and capsule endoscopes.

The perspective view of the in-vivo medical device (heart rhythm management device) in Embodiment 1 of this invention The top view of the in-vivo medical device (heart rhythm management apparatus) in Embodiment 1 of this invention The figure which shows the state which implanted the in-vivo medical device (heart rhythm management apparatus) in Embodiment 1 of this invention in the human body. The figure which shows the positional relationship of the human body which implanted the in-vivo medical device (heart rhythm management apparatus) in Embodiment 1 of this invention, and an in vitro radio | wireless communication apparatus. FIG. 3 is an exploded perspective view of an in-vivo medical device (heart rhythm management device) according to Embodiment 2 of the present invention. The top view of the in-vivo medical device (heart rhythm management apparatus) in Embodiment 2 of this invention The top view of the in-vivo medical device (capsule type endoscope) in Embodiment 3 of this invention Schematic diagram of a conventional in-vivo medical device (heart rhythm management device) Schematic diagram of a conventional in-vivo medical device (capsule endoscope)

Explanation of symbols

1 human body 2 heart 3 esophagus 4 stomach 100,500 heart rhythm management device 101,701,801 loop element 102,702 loop element grounding section 103,703 loop element tuning circuit connection 104,502,704 tuning circuit (capacitor)
105, 705 Loop element power supply unit 106, 507, 706 Radio circuit 107, 508, 707 Circuit board 108, 709 Case 109, 802, 803 Lead wire 501 Slot element 503, 504 Slot element tuning circuit connection section 505 Slot element Grounding part 506 Slot power feeding part 509 Conductive metal casing 700, 901 Capsule type endoscope 708 Imaging device 804, 902 In vitro wireless communication device 903 Display device

Claims (5)

An in-vivo medical device that is implanted into a living body or inserted into a body cavity to detect biological information and perform medical treatment, and includes a magnetic field mode antenna element for communication with an in-vitro wireless communication device An in-vivo medical device. The in-vivo medical device according to claim 1, further comprising a loop element as the magnetic field mode antenna element. The in-vivo medical device according to claim 1, further comprising a slot element as the magnetic field mode antenna element. Cardiac rhythm information detection means, and cardiac stimulation means for providing an electrical stimulation signal to the heart when the cardiac rhythm information detection means detects an abnormality, and the cardiac rhythm information detected by the cardiac rhythm information detection means The in-vivo medical device according to any one of claims 1 to 3, further comprising communication means for transmitting to the in-vitro wireless communication device. 4. The apparatus according to claim 1, further comprising: an imaging unit configured to image a body cavity, and a communication unit configured to transmit an image of the body cavity captured by the imaging unit to the in vitro wireless communication device. In vivo medical device.

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