JP2762283B2 - In vivo implantable sensor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sensor for measuring a temperature, a pressure, and the like in a living body, and in particular, emits a piezoelectric vibrator provided in the sensor when implanting the living body using an applicator. The present invention relates to an in-vivo sensor capable of easily knowing a direction in which a signal is strongest.

(Prior art) In hyperthermia, in which cancer cells are extinguished by heating with high-frequency electromagnetic waves or the like, it is indispensable to precisely measure the temperature of a heated portion in a living body. Has been proposed. As a sensor suitable for such an application, a sensor using a thermocouple has been conventionally used, and a cable is pulled out from a thermocouple embedded in a predetermined place in a living body and connected to a measuring instrument main body to perform measurement. I have.

In addition, in order to eliminate the inconvenience of a sensor with a cable in recent years, a resonator obtained by adding an antenna coil to a quartz resonator using the fact that the resonance frequency has temperature dependence is embedded as a sensor inside the pair to be measured. A wireless type has been developed in which a sensor is intermittently irradiated with an electromagnetic wave, and a reverberation signal of the sensor is extracted by an external probe while the electromagnetic wave irradiation is stopped, and the frequency is detected.

However, electromagnetic waves are easily absorbed and attenuated by constituents inside a living body such as the human body, so that the electromagnetic energy emitted to or emitted from the sensor is greatly attenuated, and the distance between the sensor and the external probe is reduced. There was a problem that it was difficult to secure a large distance.

In order to solve the above-mentioned problems, the present inventors have proposed a temperature measuring means using an ultrasonic wave having very little attenuation in a living body instead of an electromagnetic wave.

This temperature measuring means uses a quartz oscillator excellent in ultrasonic response, intermittently irradiates ultrasonic energy from the outside, and the frequency of the ultrasonic wave emitted by the sensor due to reverberation vibration during the irradiation stop period. The temperature is measured by knowing the temperature.

According to this sensor, the distance between the sensor and the external measurement device can be secured much larger than that of a sensor using a conventional electromagnetic wave, so that temperature measurement and pressure measurement in a deep part of the body can be performed. .

By the way, the above-mentioned conventional sensor is generally inserted into a living body using an applicator having a form like a syringe, and one end of the sensor has a pointed shape such as a spear ear shape in order to ease a patient's pain at the time of insertion. It is desirable to form sharply.

That is, FIG. 12 shows a sensor 3 using a quartz oscillator 2 having an electrodeless tuning-fork type vibrating piece 1 proposed by the present inventors.
FIG. 3 is an explanatory view of the structure of the present invention, in which a vibrator 2 is vacuum-sealed in a case that supports a base 2a thereof and includes a base 5 and a cap 6 having one end sharpened.

In addition, since the conventional sensor for insertion into a living body as described above uses the crystal resonator 2 having the tuning-fork type vibrating reed 1, the vibrating direction of the vibrating reed 1 indicated by the arrow, ie, the arrow A It is necessary to irradiate ultrasonic waves from the direction. Therefore, when the light is irradiated from an angle other than the proper irradiation direction, the vibrating reed 1 cannot be strongly excited, and the reverberation signal including the temperature information to be received becomes weak. It is preferable to set the direction of the irradiated surface of the child 2 to a predetermined direction in advance.

However, the conventional sensor is small and has a cylindrical shape, so the orientation of the vibrator cannot be confirmed by visual inspection of the sensor itself. There was no other way but to force the excitation by trying ultrasonic irradiation. As long as such inconvenience is involved in the measurement, there is a limit in obtaining a high measurement accuracy and an accurate therapeutic effect, and it has been desired to solve the above-mentioned drawbacks.

(Objects of the Invention) The present invention has been made in view of the above, and makes it possible to accurately confirm the direction of an ultrasonic transducer constituting a sensor when the sensor is inserted into a living body by an applicator. Accordingly, an object of the present invention is to provide an in-vivo sensor capable of effectively forcibly exciting a sensor implanted in a living body.

(Constitution of the Invention) In order to achieve the above object, the present invention relates to a sensor which is embedded in a living body by an applicator and is used for measuring a temperature and a pressure in a living body. Index sensor that indicates the direction of the excited surface of
It is formed outside the case, and is configured to fit only when the indicator is attached at a specific angle to the needle tip of the applicator.

(Examples) Hereinafter, the present invention will be described in detail based on examples shown in the accompanying drawings.

FIGS. 1 (a) and 1 (b) are a perspective view and a plan view of a first embodiment of the present invention. This wireless type temperature sensor 10 has a temperature variation on a base 11 having a pointed shape such as a spear ear. In contrast to this, a tuning fork type crystal resonator 13 having a large frequency fluctuation is fixed, and this is vacuum-sealed with the base 11 by a cap 15.

A characteristic feature of this embodiment is that the joint of the base 11 with the cap 15 and the cross-sectional shape of the cap 15 are oblong. By doing so, the ultrasonic wave irradiation direction to this sensor becomes the direction of arrow A shown in FIG.

FIG. 2 shows a modification of the first embodiment, in which the cross-sectional shape of the sensor cap 15 and the shape of the joint between the base and the cap may be a rugby ball shape (spindle shape). An index similar to the embodiment of FIG. 1 is configured.

When the above-described sensor is inserted into a living body, an applicator as shown in FIGS. 3 (a) to 3 (c) may be used. That is, the applicator 20 is a sensor as described above.
A hollow needle 21 having an internal cross-sectional shape capable of loosely fitting 10 and smoothly advancing, and a grip portion 23 supporting the needle 21,
A piston 25 inserted from the hollow portion inside the portion 23 to the hollow portion inside the needle 21, a handle 27 formed at the end of the piston 25 in a T-shape, and a long axis of the needle 21 having an elliptical cross section It has wing-shaped direction indicating pieces 29 protruding from both ends in the direction. The direction indicator piece 29 does not need to protrude from the main body 23, and may be a simple mark such as coloring or engraving. Further, since the formation position of the direction indicating piece 29 coincides with both ends in the longitudinal direction of the cross section of the sensor loaded in the needle 21, the direction of the vibrator 13 is determined using the direction indicating piece 29 as an index when the applicator is used. You can insert it while checking. Conversely, it is of course possible to form the direction indicating pieces 29 at both ends in the short axis direction of the sensor having an oval cross section. In this case, it goes without saying that the index of the applicator indicates the ultrasonic irradiation direction.

As shown in FIG. 3 (c), the sensor 10 is mounted on the applicator 20 through the opening at the rear end of the main body 23 as in the prior art (a self-contained type). The mounting is completed by pushing in the portion, and the sensor is launched by further pushing in.

Note that the direction of the sensor can be accurately confirmed simply by forming the cross-sectional shape of the grip portion 23 itself into an elliptical shape (elliptical shape) substantially similar to the shape of the needle 21.

When the outer shape of the sensor is configured in this manner, the direction (circumferential angle) of the sensor having the inner shape corresponding to the outer shape is uniquely defined, so that the positional relationship between the applicator and the crystal resonator is determined. be able to.

By using such an applicator, as shown in FIG. 4, when the sensor 10 is inserted into a living body, particularly when the sensor 10 is inserted into a human body, the sensor is given an appropriate direction for transmitting and receiving an ultrasonic signal and embedded therein. It is easy to determine the direction in which the data 20 is to be inserted.

However, sensor caps having an oval or spindle-shaped cross-section are not always easy to manufacture and it is also difficult to join such caps to a base.

Therefore, in order to obtain a sensor having a circular cross section that is the easiest to manufacture and that can specify the direction of insertion into a living body, the sensor wall may be modified as follows.

5 (a), 5 (b), 5 (c), 5 (d) and 5 (e) are a front view, a plan view, a bottom view, and a cross section showing a state of being mounted on an applicator, showing a configuration of a second embodiment of the present invention. FIG. 5 is a diagram in which a sensor 10 has a cylindrical cross-sectional shape that is easy to manufacture, and a guide groove (index) 40 is formed on an outer surface of a base 11 that is sharpened like a spear along an insertion axis direction thereof. .
The guide groove 40 may be formed on the excitation direction A orthogonal to the excitation surface 13a of the tuning fork vibrator 13 housed in the space formed by the base 11 and the cap 15, or in the direction orthogonal to the excitation direction A. .

The sensor 10 having such a configuration is used by attaching a guide ridge 41 as shown in FIG. 5 (e) to the applicator 20 having the needle 21 inside. That is, the guide ridge 41 has a shape that fits into the guide groove 40 of the sensor 10 to support the same, and the guide ridge 41 and the direction indicator piece 29 (third part) of the applicator.
The configuration may be such that the insertion direction of the sensor 10 can be known in advance based on the positional relationship with the diagrams (a), (b), and (c).

Therefore, the method of inserting the sensor using the applicator is the same as that described with reference to FIG.

However, the above-mentioned sensor is required to have high processing accuracy in consideration of its size, and is not only expensive, but also considerably difficult to use in consideration of the clearance with the inner wall of the applicator.

In order to solve this problem, it is better to further increase the size of the sensor index as shown below to facilitate handling.

FIGS. 6 (a) to 6 (d) show a third embodiment of the present invention. In contrast to the embodiment shown in FIG. 5, a concave streak is provided as an index along the outer axial direction of the sensor case. , Small wing-shaped ridges 50 are provided.

The applicator shown in FIG. 6 (d) is a preloading type in which a sensor is mounted from the tip of the needle 21. In this respect, the applicator is different from the one shown in FIG. When the sensor 10 having a protrusion such as is mounted on the applicator, this method is more convenient in order to uniquely set the angle of the sensor in relation to the needle 21.

If such a sensor is not loaded into an applicator as described above, it is necessary to provide a concave streak on the inner wall of the cavity 21 of the applicator, and as a result, it is inevitable that the needle 21 becomes significantly thicker. It is expected that the pain of patients to which this is applied will also increase.

In order to avoid this problem, a slit 51 is provided at the tip of the needle 21 of the applicator to engage the ridge 50 of the sensor as shown in FIG. You should do it.

The tip of the hollow needle 21 is different from a normal needle cut obliquely, and it is better to have a blade surface such that the entire circumference of the tip matches the tip slope of the spear of the sensor.

FIGS. 7 (a) to 7 (f) show a fourth embodiment of the present invention. When the cap 15 is manufactured by deep drawing, the upper end thereof is formed into a plate shape by a processing method such as forging, and the plate 15 is further formed into a plate shape. Both side edges of the portion 60 are blades (indexes) 61 projecting beyond the cylindrical cap body. It is preferable that the leading edge and the side edge of the blade 61 are also formed of sharp blades so that the tissue of the living body is smoothly cut when the sensor enters the living body.

It goes without saying that the applicator for mounting such a sensor may have the same configuration as that described in the embodiment of FIGS. 6 (c) and 6 (d).

FIGS. 8 (a) to 8 (d) show a fifth embodiment of the present invention, which is an improvement of the fourth embodiment of FIGS. 7 (a) to 7 (f).

That is, in the third and fourth embodiments described above, the small wing-shaped convex shape is used.
Both edges of the 50 or plate-like portion 60 project outward in the radial direction as an index, and an object having a large cross-sectional area is inserted into a living body by the amount of the projection, so that the patient to whom this sensor is applied is alleviated. There is a side note that is not enough. Thus, in the fifth embodiment, the outer diameter of the needle 21 is made the same as that of the sensor by removing the ridge portion of the blade 61 as shown in FIG. That is, the index indicating the direction of the excited surface of the crystal resonator in the sensor is a plate-like portion 60 equal to the outer diameter of the sensor. Moreover, a step 71 is provided in a continuous portion between the cap 15 and the plate-shaped portion 60.

Accordingly, as shown in FIG. 9, the applicator for loading the sensor has the same outer diameter of the needle 21 as that of the sensor 10, and forms a slit 70 of a predetermined length from the tip end toward the rear in the axial direction. I do. The ring-shaped tip surface of the needle 21 has a shape such as to be in close contact with the end surface 15c of the cap 15, for example, and the slit 70 can elastically fit and support both side edges of the plate-shaped portion 60 at a predetermined pressure. The side wall axial length of the stepped portion 71 is sufficiently given, and dimensions are set so that the portion is fitted into the inside of the needle 21.

Thus, when the sensor 10 is inserted into the tip of the needle 21, the side wall of the sensor step portion and the plate-shaped portion 60 are elastically held by the inner wall of the hollow needle 21 and the slit 70, respectively. It is embedded in a predetermined position along the direction, and the excitation direction of the crystal resonator incorporated in the sensor can also maintain the predetermined direction.

FIGS. 10 (a) to 10 (d) show a modification of the fifth embodiment, which is different from the fifth embodiment in that the radial length of the plate-shaped portion (index) 60 matches the diameter of the step portion 71. . The stepped portion 71 has a concentric planar shape with a smaller diameter than the cap body 15, and the plate-shaped portion 60 stands up to the full diameter of the stepped portion 71.

FIGS. 11 (a), (b) and (c) are explanatory views of an example of the configuration of an applicator using the sensor of FIG. 10, and the ring-shaped distal end surface of the hollow needle 21 is formed between the cap body 15 and the stepped portion 71. The needle 21 is configured to be in close contact with the step surface 15c therebetween, and the inner diameter d1 of the needle 21 is maximum at the distal end portion, and is small from a predetermined distance deep. Grooves 77a are formed at an end surface of the inner peripheral surface 77 having a small diameter at intervals of 180 degrees, and the sensor 10 is supported by fitting a side edge of the plate-shaped portion 60 into the groove 77a.

As described above, the index for supporting the excitation direction of the crystal resonator incorporated in the temperature sensor has been mainly described with reference to the embodiment in which the bases constituting the sensor case are provided with the concave or convex ridges, but the present invention is not limited thereto. Needless to say, the indicator can be attached to the side of the cap fixed to the base.

(Effects of the Invention) As described above, according to the present invention, when an in-vivo implantable sensor that obtains information such as temperature and pressure by ultrasonic transmission / reception is implanted in a living body by an applicator, the excitation surface of the quartz oscillator in the sensor is excited. Since the report can be recognized by the practitioner, there is a remarkable effect in facilitating the forced excitation by the irradiation of the ultrasonic wave after the sensor is embedded and the detection of the reverberation frequency, thereby enabling accurate measurement. Furthermore, in the case where the width of the plate-like index provided on the sensor is the same as the outer diameter of the sensor, the outer diameter of the needle of the applicator for loading the same can be the same as that of the sensor. There is also a remarkable effect of greatly reducing the pain of inserting the sensor into a patient into which the sensor is implanted.

[Brief description of the drawings]

1A and 1B are a perspective view and a plan view of a first embodiment of the present invention, FIG. 2 is an explanatory view showing a planar shape of a modification of the first embodiment, and FIG. FIG. 1 (a)
FIG. 4 (b) is an explanatory view of an example of a dedicated applicator used when inserting the sensor into a living body. FIG. 4 is a cross-sectional plan view showing a state where the sensor is inserted into a required part of a human body using the applicator. FIGS. 5 (a), 5 (b), (c), (d) and (e) show a perspective view, a front view, a plan view, a bottom view and a view showing the structure of the second embodiment of the present invention. 6 (a), 6 (b), 6 (c) and 6 (d) are a partial sectional front view, a plan view, and a sectional view of a state of being mounted on an applicator according to a third embodiment of the present invention. FIGS. 7 (a), (b), (c), (d), (e) and (f) are a front view, a plan view, a bottom view, and a partial sectional front view of a fourth embodiment of the present invention. FIG. 8 is a perspective view showing a state of use and a cross-sectional view showing a configuration of a needle tip. FIGS. 8 (a), (b), (c) and (d) show a fifth embodiment of the present invention.
Of the embodiment of. 9 (a), 9 (b), 9 (c) and 9 (d) show the configuration of the needle of the applicator to which the sensor shown in FIGS. 8 (a) to (d) is attached. FIGS. 10 (a), (b), (c) and (d) are perspective views, front views, plan views and side views of a modification of the fifth embodiment, and FIGS.
10 (a), 10 (b) and 10 (c) are explanatory views of the configuration of a needle portion of an applicator for loading the sensor of the embodiment of FIG. 10, and FIG. 12 is an explanatory view of the configuration of a conventional sensor. 10 Wireless wireless ultrasonic sensor 11 Base 13 Crystal oscillator 13a Excited surface 15 Cap 15a Pointed end 20 Applicator 21 Needle 21a Hollow tubular part, 23 body (grip), 25 piston, 27 handle, 29 direction indicator piece, 30 human body, 31 ultrasonic microphone or ultrasonic antenna, 40 … Guide groove (index) 41… Guide ridge, 50… Index 55 …… Blade (index), 56… Slit 60 …… Plate part (index), 61 …… Blade (index), 63 …… Slit, 70 ... Slit 71 ... Step, 77 ... Inner peripheral surface

Claims (5)

(57) [Claims] 1. A sensor embedded in a living body by an applicator and used for measuring a temperature, a pressure, and the like in the living body, wherein the sensor is an index indicating a direction of a surface to be excited of a piezoelectric vibrator held in the sensor. Wherein the indicator is configured to be fitted only when the indicator is attached at a specific angle to the needle tip of the applicator. 2. The in-vivo implantable sensor according to claim 1, wherein a cross section of the sensor case orthogonal to the sensor insertion axis has an oval or spindle shape as an index of the sensor. 3. The in-vivo sensor according to claim 1, wherein the index of the sensor is a recess or a ridge formed on the outer peripheral surface of the case of the sensor and extending in the axial direction. 4. The in-vivo sensor according to claim 1, wherein the index of the sensor is a blade-shaped blade formed on an outer peripheral surface of a case of the sensor and extending in an axial direction. 5. An in-vivo implantable sensor according to claim 1, wherein the index of said sensor is a plate-like portion protruding from an end face of a case constituting said sensor and extending in an axial direction.