JPS593331A - Method for measuring temperature in living body - Google Patents

Abstract

PURPOSE:To measure temperature in a living body in safety over a long period, by impressing energy which is emitted by a variable-frequency oscillator at the outside of the living body, to a crystal oscillator which is implanted into the living body, and recognizing a frequency at which said energy is absorbed, and thus detecting the temperature in the living body. CONSTITUTION:High-frequency energy from a variable-frequency oscillator 5 is radiated by a coil 3, and is transferred to a coil 2, and oscillates a crystal oscillator 1. When the frequency of the oscillator 5 and the resonance frequency of the crystal oscillator 1 coincide with each other, the oscillation of the crystal oscillator 1 becomes large, and absorbs energy. Then, the frequency at which the absorption of energy is caused is read with a frequency counter 6, by varying the frequency of the oscillator 5, under monitoring an energy detector 4. The value which is read by the frequency counter 6, reflects a temperature which the crystal oscillator 1 implanted in a living body receives from the surrounding living body.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention detects body temperature within a living body using a temperature sensor that uses a crystal oscillator that is implanted into a living body and whose resonance frequency changes depending on the temperature. The present invention relates to a method of providing temperature information outside the body using the temperature information and measuring this information with a temperature display device.

Originally, the vibration frequency of a crystal resonator is stable, but by carefully cutting the crystal, it is possible to make it so that the vibration frequency changes according to temperature changes. For example, a cut shifted 5 degrees to the plus side is an example. If an oscillation circuit is constructed using such a crystal resonator, the temperature can be determined by detecting and displaying the oscillation frequency. By the way, when trying to measure the temperature inside the body, it is necessary to implant a crystal oscillator into the body and lead a conductive wire from there to the outside of the body. However, if the conductor passes through the skin, there is a very high possibility that bacteria will enter the body from that point, making it unsuitable for long-term use. For this reason, a device in which a crystal oscillator was used as a sensor for measuring internal body temperature was never put into practical use.

Despite advances in medical technology, there has never been a time when we felt the need to know our internal body temperature safely and accurately.

The present invention solves exactly this problem by utilizing the fact that a crystal oscillator absorbs energy at its vibration frequency from outside, and applying energy to the crystal oscillator inside the body using a variable frequency oscillator from outside the body. This is a method of detecting internal body temperature by knowing the frequency at which E. lugi is absorbed.
It is obvious that this method does not require the conductor to be pulled out from the body percutaneously, and there is no invasion of bacteria into the body.
It becomes possible to safely measure the temperature inside the body over a long period of time. This makes it possible to perform repeated thermal treatments, for example, and has a great impact on the progress of medical technology.

Next, the in-vivo body temperature measurement method of the present invention will be explained together with an example of an apparatus for carrying out the method. A is the inside of the living body, B is the space outside the living body, and a temperature sensor C is implanted inside the living body A.

This temperature sensor C consists of a crystal oscillator 1 and a coil 2 connected to both ends of the crystal oscillator 1. The crystal oscillator 1 is cut so that its resonant frequency changes with temperature changes. On the other hand, a temperature display device is installed in the in vitro space B. This device consists of a variable frequency oscillator 6, an energy detector 4 connected to it, and a coil 3 connected thereto, and this coil 3 is placed opposite to the coil 2. 6 is a frequency counter connected to the variable frequency oscillator 5.

Measurement of body temperature using this device is performed as follows. The high frequency wave from the variable frequency oscillator 5 is radiated from the coil 3 and transmitted to the coil 2, causing the crystal resonator 1 to vibrate. The oscillation frequency of the variable frequency oscillator 6 is
If the resonant frequency of the crystal resonator 1 is different from that of the crystal resonator 1, the vibration of the crystal resonator 1 is small and absorbs almost no energy, but if the oscillation frequency of the variable frequency oscillator 5 and the resonant frequency of the crystal resonator 1 match, then , the vibration of the crystal resonator 1 increases and absorbs more energy. Therefore, by changing the oscillation frequency of the variable frequency oscillator 5 while monitoring the energy detector 4, and reading the frequency at which energy absorption occurs with the frequency counter 6, the resonant frequency of the crystal resonator 1 can be determined. The resonant frequency of the crystal oscillator 1 is cut so that it changes depending on the temperature, so the value read by the frequency counter 6 installed outside the body is based on the frequency of the crystal oscillator 1 implanted in the body. It reflects the temperature received from the living body, so it is possible to know the temperature inside the living body. It is easy to calibrate the relationship between the resonant frequency of the crystal resonator 1 and the temperature in advance, and the true temperature can also be displayed using a table or by a microcomputer, etc. as described later.

FIGS. 2A, B, and C show examples of the energy detection method. In FIG. In this method, the voltage across the coil 30 is detected.

FIG. 2B shows a method of connecting an energy detector 4' in series with the coil 3 in the electric circuit to detect the current flowing through the coil 3. FIG. 2C shows a transistor in the variable frequency oscillator 6.

It is possible to know energy changes by detecting the current or voltage of active elements such as vacuum tubes.Specific examples include the grid current of a vacuum tube oscillator, and the base current and collector current of a transistor oscillator. can give.

FIG. 3 shows an embodiment of the temperature display device in the case where the distance between the coil 2 and the coil 3 in FIG. 1 is large. If the coils 2 and 3 are close to each other, it is sufficient to display the output of the detector 4 directly on a meter, etc., but when measuring the temperature deep inside the living body, coil 2 moves away from the body surface,
In many cases, the coupling between coil 2 and coil 3 becomes weak, making it difficult to determine energy absorption.

To solve this problem, another oscillator 7 is connected to the variable frequency oscillator 6, and the output of this oscillator 7 is used to perform frequency modulation or amplitude modulation. As a result, the output of the detector 4 contains the oscillation frequency of another oscillator element or its harmonics, so for example, as shown in FIG. It becomes possible to use a high-gain AC amplifier 8 and a filter 11 that resonates with the fundamental wave or harmonics, and it becomes possible to dramatically improve detection sensitivity.

Figure 4 shows an example of a method of detecting the output of the energy detector through a filter, feeding it back to the variable frequency oscillator, controlling the oscillation frequency, and automatically matching it to the resonant frequency of the crystal resonator. A double balanced modulator 9 is connected in series between the filter 11 and the variable frequency oscillator 5 of the electric circuit shown in FIG.

In this embodiment, the output of the AC amplifier 8 is passed through a filter 11 that resonates with the double harmonic, and then converted to a DC signal in addition to the double-balanced modulator 9. part (e.g. variable capacitance diode)
, the oscillation frequency of the variable frequency oscillator 6 is controlled and automatically set to the frequency with the highest DC output. It is obvious that the frequency at this time coincides with the resonant frequency of the crystal resonator 1. By configuring the temperature display device as in the embodiment shown in FIG. 4, it becomes possible to know the resonant frequency of the crystal oscillator 1 implanted in the living body without any human intervention. The temperature inside the body can be measured.

If the resonant frequency of the crystal oscillator is not the same value as the biological temperature, calibrate the error in advance and connect the microcomputer 1o to the frequency measuring device 6 as shown in Fig. 4. By performing the conversion from time to time using this microcomputer 1o, it is possible to accurately measure the internal body temperature.

As mentioned above, the in-vivo body temperature measurement method of the present invention takes advantage of the property of a crystal oscillator to absorb energy at its own resonance frequency from the outside world, and implants only the crystal oscillator and coil inside the living body. It eliminates the need to implant consumables such as batteries into the body or pull out conductors outside the body, which is sanitary, can be used semi-permanently, and allows accurate information on internal body temperature to be communicated outside the body. can. This information is transmitted to an oscillator, coil, and energy detector 9 for frequency modulation or amplitude modulation such as a variable frequency oscillator installed outside the living body.
The resonant frequency of the crystal oscillator is determined by changing the oscillation frequency of the oscillator by arranging both the internal and external coils of the temperature sensor and the temperature display device to face each other, using a temperature display device consisting of a frequency measuring device connected through an electric circuit. This can be determined by detecting the frequency that matches with the energy detector with an energy detector and displaying this on the measuring instrument.

In addition, by configuring the temperature display device to automatically control the oscillation frequency of the oscillator to that frequency when it detects a frequency that matches the resonant frequency of the crystal oscillator, no troublesome operations are required. It can automatically measure the whole body temperature without having to do so.

[Brief explanation of the drawing]

The drawings show an embodiment of an apparatus for implementing the in-vivo body temperature measurement method of the present invention, and FIG. 1 is a schematic diagram showing an example of implementing the manual measurement method, and FIG. 2 A, B, Figure 2C shows an example of the wiring of an energy detector for detecting energy, and Figure 2A is a schematic diagram in which the energy detector is connected in parallel with the coil so as to detect the voltage at both ends of the coil.
Figure 2B is a schematic diagram of an energy detector connected in series with the coil to detect the current flowing through the coil, and Figure 2C is a schematic diagram of an energy detector connected to the coil to detect the current or voltage of the active element of the variable frequency oscillator. Fig. 3 is a schematic diagram of the temperature display device shown in Fig. 1 in a state where the output of the oscillator is increased, and Fig. 4 is a schematic diagram of the temperature display device shown in Fig. 1 in a state where the output of the oscillator is increased. Schematic diagram showing an example. A...Inside the living body, B...External space, C...Temperature sensor, D...Temperature display device, 1...Crystal oscillator, 2...Coil, 3...Coil, 4.4'
, 4'... Energy detector, 6... Variable frequency oscillator, 6... Frequency measuring device, 7... Oscillator, 8
...AC amplifier, 9...Double balanced modulator, 10.
...Microcomputer, 11...Filter patent applicant Yoshiaki Saito Inter-Tsuba Co., Ltd. agent Patent attorney Katsu Ohno
Reiko Ohno
Ryunosuke Ohno Figure 2 (A) (B) (C) Figure 3? Figure 4

Claims (1)

[Claims] 1. A crystal resonator whose resonant frequency changes depending on temperature;
A temperature sensor consisting of a coil connected to this crystal oscillator is implanted in the living body, while an oscillator, coil, and energy detector for frequency modulation or amplitude modulation such as a variable frequency oscillator is placed outside the living body. A temperature display device formed by connecting a frequency measuring device with an electric circuit is installed, and the above-mentioned coils provided inside and outside the living body are opposed to each other.
Energy is received and transferred between the temperature sensor and the temperature display device, and the oscillation frequency of the oscillator is changed by utilizing the property of the crystal resonator to absorb energy at a self-resonant frequency from the outside world. , when the frequency of the oscillator and the resonant frequency of the crystal oscillator match, and the crystal oscillator vibrates greatly and absorbs energy, an energy detector detects the absorption of energy, and this is measured and displayed. In-vivo body temperature measurement method that measures the body temperature inside the body. 2. A crystal resonator whose resonant frequency changes depending on the temperature,
A temperature sensor consisting of a coil connected to this crystal oscillator through an electric circuit is implanted in the living body, while a variable frequency oscillator, a coil, an energy detector, and a frequency measuring device are connected outside the body through an electric circuit. Another oscillator is connected to the frequency oscillator through another electric circuit, and the output of the second oscillator applies frequency modulation or amplitude modulation to the variable frequency oscillator. Alternatively, a filter that passes a predetermined harmonic is connected by a third electric circuit, and this filter and a double-balanced modulator are connected, and the double-balanced modulator and the variable frequency oscillator are connected by a fourth electric circuit. A temperature display device is installed, and both the coils provided inside and outside the living body are made to face each other so that energy is received and transferred between the temperature sensor and the temperature display device, and the crystal oscillator generates self-resonance. Utilizing the property of absorbing frequency energy from the outside world, the oscillation frequency of the oscillator is changed, and an energy detector detects the frequency when the oscillator frequency and the resonant frequency of the crystal oscillator match. The output is detected by the AC amplifier and filter in the third electric circuit, and the output converted to DC by the double-balanced modulator is applied to the variable frequency oscillator, thereby controlling the oscillation frequency of the variable frequency oscillator and automatically converting it to the crystal. An in-vivo body temperature measurement method that matches the resonant frequency of a vibrator to measure the body temperature within the body.