JP4934609B2 - Capsule type medical device and capsule type medical system - Google Patents

Description

  The present invention relates to a capsule medical device and a capsule medical system, and more particularly to a capsule medical device and a capsule medical system that receive information from outside the subject using the subject as a transmission medium.

  Endoscopes have been widely used in the medical field and the like. In particular, endoscopes in the medical field are mainly used for applications such as in vivo observation. And as one of the types of endoscopes described above, the subject is placed in the body cavity by swallowing, and sequentially images the subject while moving in the body cavity with the peristaltic movement, In recent years, a capsule endoscope having a function capable of transmitting an image of the captured subject as an imaging signal to the outside has been proposed.

  And as an apparatus which has a function substantially the same as the capsule endoscope mentioned above, there exists a thing proposed by patent document 1, for example.

Patent Document 1 incorporates an antenna that can be shared in transmission and reception of various signals wirelessly and a receiver unit as a receiving system for receiving an external signal from an external device, and the contents of the external signal. Discloses a configuration of a capsule endoscope that can start, stop, or change its own operation mode.
JP 2006-51336 A

  Generally, the signal level of an external signal wirelessly transmitted from an external device to a living body is added to another medical device by EMI (Electromagnetic Interference) even if the attenuation level of the signal generated by passing through the living body is added. Considering the influence of the above, it is limited to a relatively weak one. Therefore, in the capsule endoscope described in Patent Document 1, it is necessary to use an antenna and a receiver unit that have high reception sensitivity performance. As a result, in the capsule endoscope described in Patent Document 1, for example, the configuration of the antenna is complicated, and the circuit scale of the receiver unit is increased.

  The present invention has been made in view of the circumstances described above, and can receive an external signal from outside the body by a receiving system that can be configured more easily than before and can be reduced in circuit scale compared to the conventional one. It is an object of the present invention to provide a capsule medical device and a capsule medical system.

  The capsule medical device according to the present invention is a capsule medical device that can receive an external signal transmitted from outside the subject and transmitted via a conductor present in the subject inside the subject. A cover member that is formed of a dielectric material and covers each component of the capsule medical device; and an external signal that is formed of a conductor and is provided in close contact with the inner wall surface of the cover member. Inductance value is set so that a resonance circuit having a resonance frequency that is connected in series to each of the plurality of electrodes and having a frequency that substantially matches the carrier frequency of the external signal is connected. An inductor circuit includes an external signal received by the plurality of electrodes and a signal receiving circuit to which the potential difference is input.

  The capsule medical system according to the present invention includes an external device that is provided outside a subject and can transmit an external signal to the inside of the subject by using a conductor present in the subject as a transmission medium; A capsule medical device capable of receiving an external signal inside the subject, wherein the capsule medical device is formed of a dielectric, and each component of the capsule medical device A cover member that covers the element, a plurality of electrodes that are formed of a conductor and receive the external signal provided in close contact with the surface on the inner wall side of the cover member, and are connected in series to each of the plurality of electrodes And an inductor circuit having an inductance value set so that a resonant circuit having a frequency substantially equal to the carrier frequency of the external signal as a resonant frequency is configured. When, and having a signal receiving circuit for the external signal and the potential difference is input received by said plurality of electrodes.

  According to the capsule medical device and the capsule medical system of the present invention, an external signal from outside the body can be received by a receiving system that can be configured more easily than before and can be reduced in circuit scale as compared with the conventional one. Become.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 5 relate to an embodiment of the present invention. FIG. 1 is a diagram illustrating an example of a configuration of a main part of a capsule medical system in which the capsule medical device of the present embodiment is used. FIG. 2 is a block diagram showing an internal configuration of the capsule medical device of FIG. FIG. 3 is a cross-sectional view schematically showing a receiving electrode arrangement state of the capsule medical device of FIG. FIG. 4 is a block diagram showing an internal configuration of the communication apparatus of FIG. FIG. 5 is a diagram schematically illustrating how signals are transmitted through a conductor present in a subject.

  As shown in FIG. 1, the capsule medical system 101 includes a capsule medical device 2 that is placed in a body cavity by swallowing a subject 1 and that captures an image of a subject existing in the body cavity. A communication device 3 arranged outside the sample 1 and capable of communicating with the capsule medical device 2, and a terminal for performing processing based on a signal received by the communication device 3 and displaying an image of the subject The main part includes a device 4 and a portable storage medium 5 capable of inputting / outputting and recording data stored in the communication device 3 and the terminal device 4.

  In addition, the communication device 3 is arranged on the body surface of the subject 1 and one or a plurality of receiving antennas 6 capable of receiving a radio signal output from the capsule medical device 2, and arranged in the body cavity. Transmitting electrodes 7a and 7b capable of transmitting various signals to the capsule medical device 2 are connected to each other.

  As shown in FIG. 2, the capsule medical device 2 includes, for example, an LED, a light emitting element 21 that emits illumination light for illuminating a subject, and a light emitting element driving circuit 22 that controls the driving state of the light emitting element 21. And an image sensor 23 configured to capture an image of a subject illuminated by the light emitting element 21 and output the image of the subject as an imaging signal. Have.

  In addition, as shown in FIG. 2, the capsule medical device 2 includes an imaging element driving circuit 24 that controls the driving state of the imaging element 23 and an imaging signal that performs signal processing on the imaging signal output from the imaging element 23 The processing circuit 25, the modulation circuit 26 that generates a radio signal by modulating the imaging signal that has been subjected to the signal processing by the imaging signal processing circuit 25, and the radio signal generated by the modulation circuit 26 is transmitted to the communication device 3. A transmitting antenna 27; a battery 28 including a power source such as a primary battery; and a power supply circuit 29 that generates a power supply voltage for operating each unit of the capsule medical device 2 based on the electric power stored in the battery 28. It is inside the housing 10.

  Further, the capsule medical device 2 includes the receiving electrodes 30a and 30b, the receiving electrode 30a and the inductor circuit 31a connected to the GND potential, the receiving electrode 30b and the inductor circuit 31b connected to the GND potential, A receiving circuit 32 and a control circuit 33 that controls the light emitting element driving circuit 22, the imaging element driving circuit 24, the imaging signal processing circuit 25, and the modulation circuit 26 based on a signal from the signal receiving circuit 32, Has inside.

  The receiving electrodes 30a and 30b are formed of a conductor (metal) such as aluminum or copper, for example, and have a configuration (described later) that can receive various signals transmitted from the transmitting electrodes 7a and 7b. ing.

  The inductor circuits 31a and 31b are configured to have the same inductance value (for example, 10 μH).

  The signal receiving circuit 32 has a configuration capable of performing processing such as amplification, demodulation and A / D conversion on the signals received by the receiving electrodes 30a and 30b and outputting the signals. Further, the signal receiving circuit 32 generates control signal reception level data based on the signal level of the signal received at the receiving electrodes 30 a and 30 b and outputs the control signal reception level data to the control circuit 33.

  Note that the signal levels of the signals received at the receiving electrodes 30a and 30b were generated between the receiving electrode 30a and the inductor circuit 31a and between the receiving electrode 30b and the inductor circuit 31b. The signal receiving circuit 32 inputs the potential difference between the two potentials.

  The control circuit 33 controls the modulation circuit 26 to superimpose the control signal reception level data from the signal reception circuit 32 on the imaging signal sent from the imaging signal processing circuit 25 to the modulation circuit 26. As a result, a radio signal in which the control signal reception level data is superimposed on the imaging signal is generated in the modulation circuit 26, and the radio signal is transmitted to the reception antenna 6 via the transmission antenna 27.

  As shown in FIG. 3, the casing 10 has a capsule shape as a whole by watertightly joining a tip cover 10 a formed so as to have a substantially hemispherical dome shape and a body cover 10 b. It is comprised so that it may become. In the present embodiment, the casing 10 has a thickness of 0.5 mm, the maximum inner diameter of the capsule shape is 10 mm, and at least the body cover 10 b is made of a material having a relative dielectric constant of about 4. It shall be configured.

  The tip cover 10a is a material having a high resistivity and a predetermined relative dielectric constant, sufficient mechanical strength, and transparent to the imaging wavelength range, such as a cycloolefin polymer or polymer carbon Is formed into a substantially hemispherical dome shape. Since the tip cover 10 a has such a configuration, illumination light emitted from the light emitting element 21 is transmitted to the outside of the housing 10, and reflected light from a subject illuminated by the illumination light is reflected on the housing 10. It penetrates inside.

  The body cover 10b is formed of, for example, polysulfone or the like, which is a dielectric material having a high resistivity and a predetermined relative dielectric constant (about 4) and sufficient mechanical strength. Moreover, it has a volume that can cover each component such as the circuit described above.

  As shown in FIG. 3 (schematically), the receiving electrodes 30a and 30b are formed to have the same shape (strip shape or cylindrical shape), and are formed on the inner wall side surface of the trunk cover 10b. It is closely attached.

  In the present embodiment, the length in the width direction when the receiving electrodes 30a and 30b are formed in a strip shape, or the length in the length direction when the receiving electrodes 30a and 30b are formed in a cylindrical shape. Are formed to be 5 mm each. In the capsule medical device 2 of the present embodiment, as long as there are two or more receiving electrodes and are provided in close contact with the inner wall side surface of the trunk cover 10b (or the tip cover 10a). However, it does not have to be based on the shape and arrangement shown in FIG. When the receiving electrode is disposed on the tip cover 10a, a material having a relative dielectric constant of about 4 is selected for the tip cover 10a.

  As shown in FIG. 4, the communication device 3 as an external device includes a demodulation circuit 41, a reception signal processing circuit 42, a position detection circuit 43, a user interface (hereinafter abbreviated as user I / F) 44, A control circuit 45, a memory circuit 46, and a signal transmission circuit 47 are provided.

  The demodulating circuit 41 demodulates the radio signal received by the receiving antenna 6 into an imaging signal and outputs it.

  The reception signal processing circuit 42 generates image data by performing processing such as A / D conversion and noise removal on the imaging signal from the demodulation circuit 41, and outputs the generated image data to the memory circuit 46.

  The reception signal processing circuit 42 separates the control signal reception level data superimposed on the imaging signal and outputs the control signal 45 to the control circuit 45 at a timing before performing the above-described processes.

  The position detection circuit 43 detects the approximate position of the capsule medical device 2 in the body of the subject 1 based on the signal level of the imaging signal input to the demodulation circuit 41.

  The user I / F 44 has a configuration that allows various operation instructions by the user and presentation of various information to the user.

  The control circuit 45 performs various controls based on operation instructions given in the user I / F 44 with respect to each unit of the communication device 3.

  The control circuit 45 generates capsule control data for controlling each unit of the capsule medical device 2 based on an operation instruction made at the user I / F 44 and outputs the capsule control data to the signal transmission circuit 47.

  Based on the control signal reception level data output from the reception signal processing circuit 42, the control circuit 45 generates an appropriate potential difference according to the control signal reception level data between the transmission electrode 7a and the transmission electrode 7b. As described above, the signal transmission circuit 47 is controlled.

  The control circuit 45 analyzes the image of the subject according to the image data based on the image data generated by the reception signal processing circuit 42 and the detection result by the position detection circuit 43. The control circuit 45 generates position data indicating the position where the capsule medical device 2 is present in the body of the subject 1 based on the analysis result of the subject image described above, and is generated by the reception signal processing circuit 42. The memory circuit 46 is controlled to store the position data in association with the image data.

  The memory circuit 46 has a configuration that can be connected to the portable storage medium 5. The memory circuit 46 sequentially stores the image data from the reception signal processing circuit 42 and the position data associated with the image data based on the control of the control circuit 45.

  With the configuration as described above, for example, when the portable storage medium 5 is connected to the memory circuit 46, if a predetermined operation is performed in the user I / F 44, the predetermined operation is performed. Control is performed by the control circuit 45, and the image data stored in the memory circuit 46 and the position data associated with the image data are written into the portable storage medium 5.

  The signal transmission circuit 47 modulates the capsule control data from the control circuit 45 to generate a control signal as an external signal, and based on the control of the control circuit 45, the amplitude level of the voltage of the control signal Set. Then, the signal transmission circuit 47 generates a potential difference according to the amplitude level of the voltage between the transmission electrode 7a and the transmission electrode 7b, so that a current corresponding to the control signal is generated in the body of the subject 1. Operates to flow.

  Further, as shown in FIG. 4, the communication device 3 includes a battery 48 including a power source such as a primary battery or a secondary battery, and a power source for operating each unit of the communication device 3 based on the electric power stored in the battery 48. And a power supply circuit 49 for generating a voltage.

  Here, the operation of the capsule medical system 101 of the present embodiment will be described.

  First, the surgeon activates each part of the capsule medical system 101, connects the receiving antenna 6, the transmitting electrode 7a, and the transmitting electrode 7b to the communication device 3, and connects the transmitting electrode 7a and the transmitting electrode 7b. It is arranged on the body surface of the subject 1. On the other hand, the capsule medical device 2 is placed in the body cavity of the subject 1 by swallowing the subject 1.

  While each part of the capsule medical device 2 disposed in the body cavity of the subject 1 operates so as to be the number of imaging, the exposure time, the emission intensity of the illumination light, and the signal processing parameters according to the control of the control circuit 33, The subject is illuminated, an image of the subject is taken, and signal processing is performed on an imaging signal based on the subject image.

  Based on the control of the control circuit 33, the modulation circuit 26 generates a wireless signal in which the control signal reception level data from the signal reception circuit 32 is superimposed on the imaging signal from the imaging signal processing circuit 25, and sends it to the transmitting antenna 27. Output.

  The radio signal transmitted from the transmitting antenna 27 is transmitted through the body of the subject 1 while being attenuated, and then received by the receiving antenna 6.

  The demodulation circuit 41 of the communication device 3 demodulates the radio signal received by the receiving antenna 6 into an imaging signal and outputs it.

  The reception signal processing circuit 42 generates image data by performing processing such as A / D conversion and noise removal on the imaging signal from the demodulation circuit 41, and outputs the generated image data to the memory circuit 46.

  The reception signal processing circuit 42 separates the control signal reception level data superimposed on the imaging signal and outputs the control signal 45 to the control circuit 45 at a timing before performing the above-described processes.

  The position detection circuit 43 detects the approximate position of the capsule medical device 2 in the body of the subject 1 based on the signal level of the imaging signal input to the demodulation circuit 41.

  The control circuit 45 analyzes the image of the subject according to the image data based on the image data generated by the reception signal processing circuit 42 and the detection result by the position detection circuit 43. The control circuit 45 generates position data indicating the position where the capsule medical device 2 is present in the body of the subject 1 based on the analysis result of the subject image described above, and is generated by the reception signal processing circuit 42. The memory circuit 46 is controlled to store the position data in association with the image data.

  The memory circuit 46 accumulates the image data from the reception signal processing circuit 42 and the position data from the control circuit 45.

  On the other hand, the control circuit 45 operates or parameters of the capsule medical device 2 based on the image data generated by the reception signal processing circuit 42, the position data generated by the control circuit 45, and the operation instruction given in the user I / F 44. When it is determined that such control is necessary, capsule control data corresponding to the control is generated and output to the signal transmission circuit 47.

  Note that, as an element that the control circuit 45 determines that it is necessary to control the operation or parameters of the capsule medical device 2, for example, when various values are input in the user I / F 44, or the capsule In some cases, the subject changes as the medical device 2 advances. The capsule medical device 2 according to the present embodiment has a configuration and an operation that can increase or decrease the number of times of imaging every time the subject changes with its own progress. It is possible to perform control such that an image of a subject in a portion that needs to be observed is intensively acquired while suppressing acquisition of the image.

  Further, the control circuit 45 sets an appropriate potential difference according to the control signal reception level data between the transmission electrode 7a and the transmission electrode 7b based on the control signal reception level data output from the reception signal processing circuit 42. Control is performed on the signal transmission circuit 47 so as to cause this.

  The signal transmission circuit 47 modulates the capsule control data from the control circuit 45 to generate a control signal having a predetermined frequency (for example, 15 MHz), and based on the control of the control circuit 45, the control signal Sets the voltage amplitude level. Then, the signal transmission circuit 47 generates a potential difference according to the amplitude level of the voltage between the transmission electrode 7a and the transmission electrode 7b, so that a current corresponding to the control signal is generated in the subject 1. It operates so as to flow through the in-body conductive material 1a as the existing conductor.

  The control circuit 45 does not perform control based on the control signal reception level data on the signal transmission circuit 47 immediately after starting each part of the capsule medical system 101. Therefore, immediately after each part of the capsule medical system 101 is activated, the signal transmission circuit 47 sets the amplitude level of the voltage of the control signal to a predetermined reference level (for example, 5 Vp-p).

  The current generated by the potential difference between the transmitting electrode 7a and the transmitting electrode 7b passes through the surface of the subject 1 and the body conductive material 1a as shown by, for example, the thick arrow in FIG. 5, and the outer wall of the trunk cover 10b. Reach the side surface.

  By the way, the surface on the outer wall side of the casing 10 of the capsule medical device 2 is in contact with either a liquid such as a body fluid or a body wall moistened by the liquid in the body cavity of the subject 1. In such a case, the body cover 10b having a property as a dielectric is composed of a liquid such as a body fluid exhibiting an action as a conductor or a body wall moistened by the liquid, and a receiving body having an action as a conductor. The state is sandwiched between the electrodes 30a and 30b. As a result, the regions R1 and R2 surrounded by the dotted line in FIG. 5, which are regions including the in-vivo conductive material 1a, the body cover 10b, and the receiving electrodes 30a and 30b, have the same functions as the capacitor elements. It can be regarded as having.

  That is, each of the receiving electrodes 30a and 30b of the capsule medical device 2 can be regarded as having the same function as the electrode on one side of the capacitor element.

  As shown in FIG. 5, the receiving electrode 30a is connected in series to the inductor circuit 31a. Further, the inductance value (for example, 10 μH) of the inductor circuit 31a is a resonance circuit in which the portion composed of the region R1 and the inductor circuit 31a has as a resonance frequency a frequency that substantially matches a predetermined frequency (for example, 15 MHz) of the control signal. It is set to be configured. That is, the portion composed of the region R1 and the inductor circuit 31a can be regarded as having substantially the same function as an LC series resonance circuit (or LC high-pass filter) having a predetermined resonance frequency (for example, 15 MHz).

  As shown in FIG. 5, the receiving electrode 30b is connected in series to the inductor circuit 31b. Further, the inductance value (for example, 10 μH) of the inductor circuit 31b is a resonance circuit in which the portion composed of the region R2 and the inductor circuit 31b has a resonance frequency that is substantially equal to a predetermined frequency (for example, 15 MHz) of the control signal. It is set to be configured. That is, the portion composed of the region R2 and the inductor circuit 31b can be regarded as having substantially the same function as an LC series resonance circuit (or LC high-pass filter) having a predetermined resonance frequency (for example, 15 MHz).

  The frequency of the current (control signal) generated by the potential difference between the transmission electrode 7a and the transmission electrode 7b substantially matches the predetermined resonance frequency in the LC series resonance circuit including the region R1 and the inductor circuit 31a. For this reason, a voltage corresponding to the current reaching the outer wall surface of the body cover 10b is generated in the receiving electrode 30a.

  In addition, the frequency of the current (control signal) generated by the potential difference between the transmission electrode 7a and the transmission electrode 7b substantially matches the predetermined resonance frequency in the LC series resonance circuit including the region R2 and the inductor circuit 31b. For this reason, a voltage corresponding to the current reaching the outer wall surface of the body cover 10b is generated in the receiving electrode 30b.

  Further, since the in-vivo conductive material 1a has a resistance component, a voltage drop corresponding to the distance between the two electrodes occurs between the receiving electrode 30a and the receiving electrode 30b. As a result, a potential difference is generated between the receiving electrode 30a and the receiving electrode 30b.

  The signal reception circuit 32 generates control signal reception level data based on the potential difference generated between the reception electrode 30 a and the reception electrode 30 b and outputs the control signal reception level data to the control circuit 33.

  Further, the signal receiving circuit 32 amplifies the input potential difference, demodulates the control signal based on the amplified potential difference, and performs A / D conversion on the control signal, thereby controlling the capsule. Get the data. Then, the signal receiving circuit 32 outputs the acquired capsule control data to the control circuit 33.

  Based on the capsule control data from the signal receiving circuit 32, the control circuit 33 appropriately performs control for changing, for example, the number of times of imaging per second, the exposure time, the illumination light emission intensity, the signal processing parameters, and the like.

  On the other hand, the control signal reception level data generated by the signal reception circuit 32 is fed back to the communication device 3 through the above-described path. In the capsule medical system 101 according to the present embodiment, such a feedback is repeatedly performed, whereby the potential difference between the transmission electrode 7a and the transmission electrode 7b is changed according to the control signal reception level data. It can be set while changing as appropriate. Therefore, in the capsule medical system 101 of the present embodiment, the capsule medical device 2 stably receives a control signal transmitted from the communication device 3 and then transmitted through the in-vivo conductive material 1a. Can do.

  As described above, the receiving electrodes 30a and 30b as a part of the receiving system in the capsule medical device 2 of the present embodiment do not have a complicated configuration, and the surface on the inner wall side of the trunk cover 10b. It is formed as a band-like or cylindrical metal provided in close contact with the metal. The receiving electrodes 30a and 30b are only connected to an inductor circuit and do not have a complicated configuration. Furthermore, as described above, the signal receiving circuit 32 as a part of the receiving system in the capsule medical device 2 according to the present embodiment transmits a relatively low frequency (for example, transmitted through the body conductive material 1a). Any circuit having a circuit configuration capable of amplifying and demodulating a signal of 15 MHz) may be used.

  Therefore, the capsule medical device 2 in the capsule medical system 101 of the present embodiment can be easily configured compared to a conventional receiving system having a configuration for receiving a relatively high frequency external signal (radio signal), and An external signal from outside the body can be received by a receiving system capable of reducing the circuit scale. In addition, the capsule medical device 2 in the capsule medical system 101 of the present embodiment consumes power during operation compared to a conventional reception system having a configuration for receiving a relatively high frequency external signal (radio signal). With a low reception system, external signals from outside the body can be received.

  Note that the present invention is not limited to the above-described embodiments, and various modifications and applications can be made without departing from the spirit of the invention.

The figure which shows an example of a structure of the principal part of the capsule type medical system with which the capsule type medical apparatus of this embodiment is used. The block diagram which shows the internal structure of the capsule type medical device of FIG. Sectional drawing which showed typically the arrangement | positioning state of the electrode for reception which the capsule medical device of FIG. 1 has. The block diagram which shows the internal structure of the communication apparatus of FIG. The figure which showed typically a mode that a signal was transmitted through the conductor which exists in a subject.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Subject 1a Conductive substance in a body 2 Capsule type medical device 3 Communication device 4 Terminal device 5 Portable storage medium 6 Receiving antenna 7a, 7b Transmitting electrode 10 Housing 10a Tip cover 10b Trunk cover 26 Modulating circuit 27 Transmitting antenna 30a, 30b Receiving electrodes 31a, 31b Inductor circuit 32 Signal receiving circuit 33, 45 Control circuit 47 Signal transmitting circuit 101 Capsule type medical system

Claims (4)

A capsule medical device capable of receiving an external signal transmitted from the outside of a subject and transmitted via a conductor present in the subject inside the subject,
A cover member formed of a dielectric and covering each component of the capsule medical device;
A plurality of electrodes that are formed of a conductor and receive the external signal provided in close contact with the inner wall surface of the cover member;
An inductor circuit in which an inductance value is set such that a resonance circuit is connected in series to each of the plurality of electrodes and includes a resonance frequency having a frequency that substantially matches the carrier frequency of the external signal;
A signal receiving circuit to which an external signal received by the plurality of electrodes and a potential difference thereof are input;
A capsule-type medical device comprising:   2. The capsule medical device according to claim 1, wherein the inductance values of the inductor circuits connected in series to the plurality of electrodes are the same value. An external device that is provided outside the subject and can transmit an external signal to the inside of the subject by using a conductor present in the subject as a transmission medium, and the external signal inside the subject A capsule medical system comprising: a receivable capsule medical device,
The capsule medical device is:
A cover member formed of a dielectric and covering each component of the capsule medical device;
A plurality of electrodes that are formed of a conductor and receive the external signal provided in close contact with the inner wall surface of the cover member;
An inductor circuit in which an inductance value is set such that a resonance circuit is connected in series to each of the plurality of electrodes and includes a resonance frequency having a frequency that substantially matches the carrier frequency of the external signal;
A signal receiving circuit to which an external signal received by the plurality of electrodes and a potential difference thereof are input;
A capsule-type medical system comprising:   The capsule medical system according to claim 3, wherein the inductance values of the inductor circuits connected in series to each of the plurality of electrodes have the same value.

Images