JP2007275451A - In vivo apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in vivo apparatus having an antenna, wherein in vivo performance is raised by covering the antenna with a dielectric case. <P>SOLUTION: The in vivo apparatus 100 includes: a loop element 101; and the dielectric case 102 for covering the loop element 101, and is constituted so as to make communication with a device arranged outside of a living body. Consequently, the in vivo performance of the antenna is raised and communication performance with the device arranged outside of the living body is raised. The apparatus may be applied for observing the electrocardiogram of a heart 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a device implanted in a living body, and more particularly to an antenna of an in-vivo medical device for performing communication with an in-vitro wireless communication device.

  Currently, in-vivo medical devices that are implanted in vivo and perform medical care are placed outside the body in order to enable transmission of various medical data (eg, electrocardiogram) regardless of the behavior of the medical staff and the posture of the patient. Development of an in-vivo medical device equipped with a function of communicating with a wireless device has been performed. In the world, regulations for setting the used frequency band to 402 MHz to 405 MHz are being prepared in various countries around the world.

  On the other hand, in general, in-vivo medical devices are rapidly becoming smaller in order to reduce the burden on the patient as much as possible.

  Here, in order to ensure the performance of the antenna, it is generally sufficient to set the antenna length to a half wavelength. However, in order to be mounted in an in vivo medical device that is implanted in a living body and is desired to be downsized, the antenna is 50 mm. The following is required. This is as small as about one-tenth of a wavelength of about 750 mm in the 400 MHz band. Therefore, there is a problem that the radiation resistance of the antenna is reduced and the radiation performance is deteriorated (sensitivity is deteriorated). .

  From these backgrounds, as a method for improving the radiation characteristics of an antenna, for example, as described in Patent Document 1, in FIG. 6, the configuration of an antenna in an implantable defibrillator is shown as a conventional in-vivo medical device. It is shown. In FIG. 6, an implantable cardioverter defibrillator 600 connects one terminal of a pulse generator 609 to an antenna 601 (antenna wire 602, lead wire 604) supported by a resin header 606, and connects the other terminal to a metal. By connecting to the housing 603 at the housing ground point 607, the antenna 601 and the metal housing 603 are operated as electrodes of the pulse generator 609, and the wireless circuit 105 is grounded to the wireless circuit ground 608 instead of the housing ground point 607. The transformer 611 is arranged between the (secondary winding 613 side) and the antenna 601 (primary winding 612 side).

  With this configuration, the lead wire 604 (the electrode of the pulse generator 609), which is the largest component, can be used as the antenna 601, so that the radiation characteristics of the antenna can be improved.

  Further, for example, as described in Patent Document 2, FIG. 7 shows a configuration of an antenna at a distal end portion of a radiation applicator for coupling radiation to a living body in a radiation applying apparatus used for microwave cutting of a living tissue. Has been. In FIG. 7, the radiation applicator tip 700 shows the end of a coaxial cable, which has an outer conductor spaced from the core conductor 705, between the core conductor and the outer conductor. Is filled with a dielectric material 707 and an antenna 701 for emitting radiation propagated by the coaxial cable is formed by a coaxial cable core conductor 705 extending beyond the outer conductor 706 at the distal end of the coaxial cable. The dielectric element 702 covers the near-field field of the radiation.

With this configuration, energy consumption in the vicinity of the antenna can be suppressed, and energy can be transmitted to the living body.
US Pat. No. 6,505,072 (FIG. 1) Japanese translation of PCT publication No. 2002-541884 (page 16, FIG. 2)

  However, in the conventional configuration described in Patent Document 1, the configuration around the antenna used as the lead wire is unclear, and the dielectric constant of the medium around the antenna is not optimized. However, there is a problem that radiation performance such as mismatch loss and antenna gain is low.

  In addition, the conventional configuration described in Patent Document 2 aims to suppress energy consumption in the vicinity of the antenna and propagate energy to the living body. Therefore, the antenna performance is low and the apparatus is disposed outside the living body. There was a problem that the communication performance with was low.

  In order to solve the above problems, the present invention provides an in-vivo device provided with an antenna that has high antenna performance in vivo and high communication performance with a radio device placed outside the living body by covering the antenna with a dielectric. It is to provide.

  In order to solve the above-described conventional problems, an in-vivo device of the present invention includes an antenna mounted on a device disposed inside a living body, and a dielectric having a predetermined dielectric constant that covers the antenna, and is disposed outside the living body. It is characterized in that it communicates with a device to be operated.

  With this configuration, the in-vivo antenna performance can be increased, and the communication performance with an apparatus disposed outside the living body can be increased.

  The in-vivo device of the present invention has a configuration in which a space between the antenna and the dielectric is filled with a dielectric.

  With this configuration, the antenna performance improvement effect in vivo by covering the antenna with a dielectric can be increased, and the communication performance with an apparatus placed outside the living body can be increased.

  The in-vivo device of the present invention has a configuration in which the antenna is arranged at the center of the dielectric.

  With this configuration, the effect of improving the in-vivo antenna performance by increasing the thickness of the dielectric is increased, and the communication performance with an apparatus placed outside the living body can be increased.

  In the in-vivo device of the present invention, the antenna is formed of a magnetic field antenna such as a loop antenna.

  With this configuration, the effect of improving the in-vivo antenna performance by being covered with a dielectric is increased, and the communication performance with an apparatus placed outside the living body can be increased.

  As described above, according to the present invention, the antenna performance in the living body can be enhanced by covering the antenna mounted on the device disposed inside the living body with the dielectric having a predetermined dielectric constant. The communication performance with the device arranged outside the living body can be improved.

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

(Embodiment 1)
1 is an antenna configuration diagram of an in-vivo device according to Embodiment 1 of the present invention, FIG. 2 is an arrangement example of the in-vivo device according to Embodiment 1 of the present invention, and FIG. 3 is an embodiment of the present invention. The antenna performance change with respect to the dielectric constant change of the dielectric material case in the form 1 is shown. Note that the operation frequency is set to 403.5 MHz, for example.

  In FIG. 2, if the in-vivo device 100 is an apparatus that observes an electrocardiogram or the like of the heart 2, for example, as shown in FIG. 2, a lead wire 104 disposed inside the human body 1 and mounted on the in-vivo device 100. Is fixed to the heart 2, observes information from the heart 2, communicates with the in vitro wireless communication device 110 equipped with the antenna element 111 arranged outside the living body, and transfers data such as an electrocardiogram.

  In FIG. 1, the housing 103 of the in-vivo device 100 is set to have a length of about 50 mm, a width of 50 mm, and a thickness of about 15 mm, for example. The loop element 101 has, for example, a long side of about 50 mm and a short side of about 15 mm, one of which is connected to the ground 109 at the antenna ground point 108 and the other is connected to the wireless circuit 105 via the matching circuit 106. The dielectric case 102 covering the loop element 101 is set to have a length of 52 mm, a width of 25 mm, a thickness d of about 15 mm, and a relative dielectric constant of about 5, for example. ing. The matching circuit 106 has a function of matching impedance between the loop element 101 and the wireless circuit 105. The detection device 107 is connected to a lead wire 104 for observing information from the heart (such as an electrocardiogram).

  The antenna performance improvement effect of the in-vivo device configured as described above will be described. As shown in FIG. 3, the relative permittivity of the case where the loop element 101 is not covered with the dielectric case 102 and the dielectric case 102 covering the loop element 101 (in this case, 52 mm in length, 25 mm in width, and d15 mm in thickness) When changed, there is a difference of 14 dB at maximum in the in vivo performance of the antenna. Therefore, by adjusting the relative permittivity of the dielectric case 102 and determining the relative permittivity that maximizes the in vivo performance (in this case, the relative permittivity is 5), the in vivo performance of the loop element 101 is Compared with the case where the dielectric constant is 1, it can be improved by 7 dB and 14 dB compared with the case where the dielectric case 102 is not covered.

  As described above, according to the first embodiment, the antenna performance of the in-vivo device is improved by covering the antenna with the dielectric case having a predetermined dielectric constant, and communication with the in-vitro wireless communication device is performed. The performance can be improved.

(Embodiment 2)
FIG. 4 is a diagram of the antenna configuration of the in-vivo device according to the second embodiment of the present invention, and FIG. 5 is a diagram illustrating the thickness d on one side of the case when the antenna according to the second embodiment of the present invention is covered with a dielectric case. The change of in-vivo antenna performance is shown.

  In FIG. 4, a dielectric case 102 covering the loop element 101 is set, for example, to a length of 52 mm, a width of 25 mm, a thickness of about 15 mm, and a relative dielectric constant of about 5, and the loop element 101 is arranged at the center in the thickness direction of the dielectric case. Configure as follows.

  The antenna performance improvement effect of the in-vivo device configured as described above will be described. As shown in FIG. 5, the loop element 101 is covered with a dielectric case 102, and only one surface of the loop element 101 is covered with a dielectric case 102 having a thickness d in the thickness direction of the dielectric case 102 ( From the case where the loop element 101 is disposed at the end in the thickness direction of the dielectric case 102), each surface is covered with the thickness d, that is, the dielectric case 102 having a thickness 2d on both sides (the thickness direction of the dielectric case 102). In the case where the loop element 101 is disposed at the center of the in-vivo antenna), the effect of improving the in-vivo antenna performance with respect to the thickness d of one side of the dielectric case is enhanced. Considering the case where the thickness d of one side of the dielectric case 102 is 7 mm, the antenna of the in-vivo device is such that the one side of the loop element 101 is covered with the dielectric case 102 rather than the one side of the loop element 101 is covered with the dielectric case 102. The performance improvement effect can be increased by 10 dB. Further, considering the case where the size of the dielectric case is the same, and considering the case where the total thickness is 3 mm, the antenna performance improvement effect is 7 dB when d = 1.5 mm on both sides rather than d = 3 mm on one side. Can be high.

  As described above, according to the second embodiment, by arranging the antenna at the center in the thickness direction of the dielectric case covering the antenna, the antenna performance improvement effect of the in-vivo device is enhanced, and the in-vivo antenna is improved. The performance is improved, and the communication performance with the in vitro wireless communication device can be improved.

  An in-vivo device of the present invention includes an antenna mounted on a device disposed inside a living body, and a dielectric having a predetermined dielectric constant that covers the antenna, and communicates with an in-vitro wireless device disposed outside the living body. The antenna performance in the living body can be improved by covering the dielectric with the antenna, and the communication performance with the in-vitro wireless device arranged outside the living body can be improved. It is useful as a configuration of an antenna mounted on a device implanted in a living body, such as a pacemaker or an implantable defibrillator.

Antenna configuration diagram of in-vivo device according to Embodiment 1 of the present invention The figure which shows the example of human body arrangement | positioning of the in-vivo apparatus in Embodiment 1 of this invention. The figure which shows the antenna performance change with respect to the dielectric constant change of the dielectric material case in Embodiment 1 of this invention. Antenna configuration diagram of in-vivo device in Embodiment 2 of the present invention The figure which shows the change of in-vivo antenna performance with respect to the thickness d of the single side | surface of a case in the case of covering the single side | surface and both surfaces of the antenna in Embodiment 2 of this invention with a dielectric material case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Human body 2 Heart 100 In-vivo apparatus 101 Loop element 102 Dielectric case 103 Case 104 Lead wire 105 Wireless circuit 106 Matching circuit 107 Detection apparatus 108 Antenna grounding point 109 Ground 110 In-vivo wireless communication apparatus 111 Antenna element

Claims (3)

An antenna mounted on a device disposed inside the living body;
A dielectric having a predetermined dielectric constant covering the antenna,
An in-vivo device that communicates with an in-vitro wireless device disposed outside a living body. The in-vivo device according to claim 1, wherein the gap between the antenna and the dielectric is filled with the dielectric. The in-vivo device according to claim 1, wherein the antenna is configured by a magnetic field antenna such as a loop antenna.

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