JP3052532B2 - Ultrasonic transmission inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic transmission inspection apparatus or a bone mineral quantification apparatus used for diagnosing osteoporosis.

[0002]

2. Description of the Related Art Osteoporosis is a symptom in which the density of bone tissue is reduced due to lack of calcium or the like. For the diagnosis, ultrasonic waves are passed through the bones, and the speed (sonic velocity) and attenuation of the ultrasonic waves in the bones. A method of quantitatively measuring the properties of bone (bone mineral density, stiffness, etc.) by measuring the density has been already devised. Such ultrasonography is typically performed on the heel of the thin foot of soft tissue.

[0003] A conventional apparatus for measuring the characteristics of bone (called a bone mineral quantifying apparatus) includes a container (measurement tank) in which an ultrasonic generator and an ultrasonic detector are attached to an inner wall so as to face each other. use. As the ultrasonic generator and the ultrasonic detector, an apparatus called an ultrasonic transducer, which can generate and detect ultrasonic waves by one unit, is usually used. Into the measuring tank, put a foot so that the heel blocks between the ultrasonic wave generator and the detector, and furthermore, for the purpose of matching when the ultrasonic wave is incident on the heel (that is, the ultrasonic wave reflected on the surface of the heel). Fill with water as a matching liquid (to minimize acoustic waves). When you emit ultrasonic waves from the generator in that state,
When passing through the calcaneus, the ultrasound propagates at a speed corresponding to the amount of bone mineral and is attenuated. Therefore, by measuring the speed or attenuation of the ultrasonic wave with the detector, it is possible to measure the amount corresponding to the amount of bone mineral of the calcaneus as the subject.

[0004] In the conventional ultrasonic bone mineral quantifying apparatus, the velocity vb of the ultrasonic wave in the bone is determined by the ultrasonic wave propagation time when the space between the generator and the detector is filled only with water and the calcaneus intervening therebetween. The time difference Δt from the propagation time at that time (usually, the velocity of sound is higher in the inside of the bone, so Δt is a negative value) is obtained by calculation using the following equation. That is, the thickness of the calcaneus (the length in the ultrasonic wave propagation direction) is Lb,
Assuming that the velocity of the ultrasonic wave in water is vw, the velocity vb of the ultrasonic wave in the bone is calculated as follows: vb = Lb / (Lb / vw + Δt) By applying the speed vb to the relationship between the speed vb and the bone mineral equivalent amount previously determined by the dual energy X-ray quantitative method or the like, the bone mineral equivalent amount can be obtained.

[0005]

Conventionally, the thickness Lb of the calcaneus
Was measured by sandwiching the heel with a compass or the like, but this had the following problems. One is that the location measured by the compass may be different from the location where the ultrasound passes in the bone mineral quantification device, and the other is the distance Lb measured by the strength applied to the compass.
Is to change. These factors cause an error in the Lb value, and eventually cause an error in the calculated bone mineral density.

In addition, the above equation includes a difference Δt between the ultrasonic wave propagation time in the case of water only and the propagation time after the foot is put, and
Contains the velocity vw of the ultrasonic wave in water. For this reason, conventionally, before putting a foot into the measuring tank, or after measuring the ultrasonic propagation time by putting a foot, in a state where only the water is filled in the measuring tank, the ultrasonic wave propagation time and the The velocity vw of the sound wave was measured. Here, since the sound velocity vw changes depending on the temperature of the water, a device for controlling the temperature of the water to a constant value has conventionally been provided in the bone mineral quantifying device. However, strictly speaking, the temperature of the water may change depending on the body temperature before and after putting the foot on. In addition, if water moves in the measuring tank, accurate measurement cannot be performed due to fluctuations in temperature and density. In order to avoid such error factors, in the conventional bone mineral quantification device, after putting the foot or after putting out the foot, the temperature of the water is stable,
I had to wait for a while until the movement of the water subsided. For this reason, there was a problem that it took a little time for one measurement.

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and an object of the present invention is to provide an ultrasonic bone mineral quantifying apparatus (a general apparatus) capable of performing more accurate measurement in a short time. Is to provide an ultrasonic transmission inspection apparatus).

[0008]

Means for Solving the Problems According to a first aspect of the present invention, which has been made to solve the above-mentioned problems, the characteristics of a subject are measured by measuring the speed, attenuation, etc. of an ultrasonic wave passing through the subject. In an ultrasonic transmission inspection apparatus to be inspected, a) a measuring tank into which an object and an ultrasonic matching liquid are put, and b) a first ultrasonic generator and a first ultrasonic wave provided near one inner wall of the measuring tank. C) a second ultrasonic generator and a second ultrasonic wave provided in close proximity to the other inner wall of the measuring tank so as to face the first ultrasonic generator, the first ultrasonic detector, D) a time t1 from when the ultrasonic wave is emitted from the first ultrasonic wave generator to when the ultrasonic wave is detected by the first ultrasonic wave detector, and
Means for measuring a time t2 from when the ultrasonic wave is emitted from the second ultrasonic wave generator to when the ultrasonic wave is detected by the second ultrasonic wave detector; e) an ultrasonic wave passing direction based on the times t1 and t2; Means for calculating the thickness of the subject.

According to a second aspect of the present invention, there is provided an ultrasonic transmission inspection apparatus for inspecting characteristics of an object by measuring the speed, attenuation, etc. of an ultrasonic wave passing through the object. A measurement tank for containing a sonic matching liquid; and b1) a non-intervening part ultrasonic generator and a non-intervening part ultrasonic detector provided on the inner wall of the measurement tank so as to face a portion where no subject is interposed. On the inner wall of the measurement tank, there is provided an interposed portion ultrasonic generator and an interposed portion ultrasonic detector provided opposite to a portion where the subject intervenes.

Here, the first ultrasonic generator and the first ultrasonic detector may be shared by a single ultrasonic transducer. In this case, by making the ultrasonic waves emitted from the ultrasonic transducer pulse-like,
The detection can be performed by the same transducer while the ultrasonic waves are not emitted, and the dual-use is possible. The same applies to the second ultrasonic generator and the second ultrasonic detector.

[0011]

According to the ultrasonic transmission inspection apparatus of the first invention, the thickness (distance in the ultrasonic wave propagation direction) of the subject is obtained as follows. First, the subject is placed in a position in the measurement tank between the first and second ultrasonic generators and detectors facing each other, and ultrasonic waves are emitted from the first ultrasonic generator. A part of the ultrasonic wave is reflected on the surface of the subject and returns to the first ultrasonic detector. The time t from when this ultrasonic wave is emitted until it returns
By measuring 1, the distance L1 from the inner wall surface of the measuring tank to the surface of the subject can be obtained. Similarly, the distance L2 from the inner wall surface to the surface of the subject can be obtained by measuring the reciprocation time t2 of the ultrasonic pulse for the second ultrasonic generator / detector. By subtracting these distances L1 and L2 from the distance L between both inner wall surfaces of the measuring tank, the thickness Lo of the subject can be obtained.

When calculating the distances L1 and L2 from the times t1 and t2, the velocity v of the ultrasonic wave in the ultrasonic matching liquid is calculated.
Is required, and this is performed between the first ultrasonic generator and the second ultrasonic detector without interposing the subject between the first and second ultrasonic generators / detectors (or By measuring the time t of the ultrasonic wave propagating between the second ultrasonic generator and the first ultrasonic detector, v = L / t can be obtained. As in the case of an ultrasonic transmission inspection apparatus according to a second invention described later, another ultrasonic wave generation / detection pair may be provided at a place where no subject is interposed, and v may be obtained by this.

In the ultrasonic transmission inspection apparatus according to the second aspect of the present invention, when the subject is put into the measuring tank, the ultrasonic velocity and the ultrasonic velocity in the subject are measured by the intervening part ultrasonic generator / detector pair in the same manner as in the conventional apparatus. The amount of attenuation, etc. can be obtained, but at the same time,
The speed and attenuation of the ultrasonic wave in the ultrasonic matching liquid can be obtained by the non-intervening part ultrasonic wave generation / detector pair. For this reason, it is not necessary to perform the measurement again in a state where the subject is not placed in the measurement tank, and the time for stabilizing and stopping the ultrasonic matching liquid is not required, and the measurement can be completed in a short time.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic bone mineral quantifying apparatus according to one embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the apparatus includes a measuring unit 10, a water control unit 11, and an ultrasonic oscillation control unit 1.
2. It comprises an ultrasonic measurement unit 13, a control unit 14, and a display unit 15. The measurement section 10 includes a measurement tank 20 for putting a foot (heel) as a subject, and two pairs of ultrasonic transducers 21 and 22 provided to face the inner wall of the measurement tank 20. Further, the control unit 14 includes a sound speed / attenuation amount calculating unit 16 that calculates the sound speed and the attenuation amount of the ultrasonic wave, and a bone mineral equivalent amount converting unit 17 that converts the calculated values into the bone mineral equivalent amount. included. In each ultrasonic transducer pair 21, 22, the transducers 21a and 21b face each other, and the transducers 22a and 22b face each other. These transducers 21a, 21b, 22
a, 22b, ultrasonic oscillation control unit 12, and ultrasonic measurement unit 1
3 is connected as shown in FIG.

The measurement of bone mineral density by the ultrasonic bone mineral density measuring apparatus is performed as follows. First, the heel 26, which is the subject, is placed in the measurement tank at a position where only one transducer pair 22 is blocked and the other transducer pair 21 is not blocked (FIG. 5A). Next, water, which is an ultrasonic matching liquid, is put into the measurement tank from the inlet 23 by the water control unit 11. Here, the water injected into the measuring tank is controlled in advance so that the temperature is constant. Measurement tank 20
When it is detected by the water level meter 24 provided on the inner wall that the water level in the measuring tank has reached a predetermined level, the water control unit 11
Stops water injection. Thereafter, the measurement is started after the water is stabilized.

At the time of measurement, the control unit 14 controls the velocity vw of the ultrasonic wave in the water and the velocity (vw) of the ultrasonic wave in the water by the transducer pair 21 without the heel (corresponding to the non-intervening part ultrasonic generator and detector in the second invention). The amount of attenuation rw (per unit distance) is measured. First, an ultrasonic pulse is emitted from one of the transducers 21a by the ultrasonic oscillation control unit 12, and the ultrasonic pulse is received by the other transducer 21b.
Is measured by the ultrasonic measurement unit 13. Since the distance L between the two transducers 21a and 21b is known, the velocity vw of the ultrasonic wave in the water under the current conditions can be obtained as vw = L / tw. Further, the attenuation rw is obtained by measuring the intensity of the ultrasonic wave detected by the transducer 21b on the receiving side by the ultrasonic measuring unit 13 and comparing the measured intensity with the intensity of the ultrasonic wave generated by the transducer 21a on the generating side. be able to. These are the control unit 14
The sound speed / attenuation amount calculation unit 16 within the calculation.

On the other hand, the transducer pair 22 on which the heel 26 is interposed (the transducers 22a and 22b constituting the transducer pair 22 correspond to the first and second ultrasonic generators and detectors in the first invention, respectively). With this, the thickness of the heel 26 is measured. As shown in FIG. 3, each of the transducers 22a and 22b emits an ultrasonic pulse from each of the transducers 22a and 22b, and the ultrasonic waves reflected by the surface of the heel 26 and returned are detected by the transducers 22a and 22b themselves. The ultrasonic measuring unit 13 includes:
With respect to 22b, the times t1 and t2 (FIG. 4) from the emission of the ultrasonic pulse to the detection are measured. Based on the measured values t 1 and t 2, the control unit 14 determines whether each of the transducers 22 a and 22
The distances L1 and L2 between b and the surface of the heel 26 are calculated as L1 = vw · t1 / 2 and L2 = vw · t2 / 2. The thickness Lb of the heel 26 is calculated as Lb = L-L1-L2.

Finally, a pair of transducers 22 in which the heel 26 is interposed (each of the transducers 22a and 22b here correspond to the interposed portion ultrasonic generator and the detector of the second invention, respectively) is used for the calcaneus. Ultrasonic velocity vb
And the attenuation rb are measured. That is, an ultrasonic pulse is emitted from one transducer 22a and detected by the other transducer 22b (or vice versa), and the time twb and the intensity of the detected ultrasonic wave are measured. From this measured value, the ultrasonic velocity vb in the calcaneus can be calculated as described above as vb = Lb / (Lb / vw + Δt) Δt = twb−tw. Alternatively, as shown in FIG. 3B, it can be calculated as vb = Lb / (tw−t1 / 2−t2 / 2). Also, the attenuation rb of the ultrasonic wave in the calcaneus can be calculated by substituting the detected ultrasonic wave intensity value into a predetermined formula. The value of the thickness Lb of the calcaneus is also required for the calculation of the attenuation. However, by substituting the value Lb calculated as described above, the attenuation can be measured with good reproducibility. The bone mineral equivalent conversion unit 17 calculates the bone mineral equivalent based on the ultrasonic velocity or attenuation thus calculated, and displays the result on the display unit 15.

In order to improve the accuracy, as shown in FIG. 5B, a plurality of pairs of transducers are provided at a position where the subject intervenes and at a position where the subject does not intervene, and the average value of the measured values is used as a basis for calculation. You may make it. Further, in the above embodiment, the bone mineral quantifying apparatus using the calcaneus as a subject is exemplified.
The present invention can be applied to general ultrasonic transmission measuring devices such as those using soft tissue as a subject in addition to bone.

[0020]

According to the ultrasonic transmission inspection apparatus of the first invention, the position where the thickness of the subject is measured becomes the position where the ultrasonic transmission measurement is performed as it is, and a measurement error due to a discrepancy between the two can be prevented. Further, since the thickness is measured in a non-contact manner, the thickness can always be measured under constant conditions regardless of the hardness of the subject. As a result, the measurement conditions at the time of bone mineral quantification are always constant, and the reproducibility of the measured values is guaranteed. In the ultrasonic transmission inspection apparatus of the second invention, the measurement of the ultrasonic matching liquid is performed simultaneously with the measurement of the subject.
It is easy to make the measurement conditions such as the temperature of the matching liquid constant, and the reproducibility of the measured values is improved. In addition, since both measurements need to be performed only once, time for stabilizing and stopping the ultrasonic matching liquid is not required, and the measurement time can be shortened.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an ultrasonic bone mineral quantification device according to one embodiment of the present invention.

FIG. 2 is a block diagram showing a connection relationship among an ultrasonic transducer, an ultrasonic oscillation control unit, and an ultrasonic detection unit of the bone mineral quantifying device according to the embodiment.

FIG. 3 is a cross-sectional view of a state where a heel, which is a subject, is placed in a measurement tank.

FIG. 4 is a timing chart when measuring the propagation time of an ultrasonic wave using an ultrasonic pulse.

FIG. 5 is a plan view showing a positional relationship between a transducer pair and a subject in a measurement tank.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Measurement part 20 ... Measurement tank 21,22 ... Transducer pair 23 ... Water inlet 24 ... Water level meter

Claims (2)

(57) [Claims] 1. An ultrasonic transmission inspection apparatus for inspecting characteristics of an object by measuring the speed, attenuation, etc. of an ultrasonic wave passing through the object, a) placing the object and an ultrasonic matching liquid inside A measuring tank; b) a first ultrasonic generator and a first ultrasonic detector provided near one inner wall of the measuring tank; c) the first ultrasonic generator and the first ultrasonic detector; A second ultrasonic generator and a second ultrasonic detector provided so as to be opposed to each other on the other inner wall of the measuring tank; and d) first ultrasonic waves are emitted from the first ultrasonic generator. The time t1 until the ultrasonic wave is detected by the ultrasonic wave detector, and
Means for measuring a time t2 from when the ultrasonic wave is emitted from the second ultrasonic wave generator to when the ultrasonic wave is detected by the second ultrasonic wave detector; e) an ultrasonic wave passing direction based on the times t1 and t2; Means for calculating the thickness of the subject. 2. An ultrasonic transmission inspection apparatus for inspecting characteristics of an object by measuring the speed, attenuation, etc. of an ultrasonic wave passing through the object, a) placing the object and an ultrasonic matching liquid inside B1) a non-intervening part ultrasonic generator and a non-intervening part ultrasonic detector provided on the inner wall of the measuring tank and opposed to a portion where the subject does not intervene; b2) the inner wall of the measuring tank An ultrasonic transmission inspection apparatus, comprising: an interposed portion ultrasonic generator and an interposed portion ultrasonic detector provided opposite to a portion where a subject intervenes.