JP2017047193A - Biological measurement apparatus, biological measurement method, and detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure information inside a living body by using a noninvasive and simple method without burdening a subject's body as much as possible.SOLUTION: An exciter 1 gives an oscillatory wave having a single frequency selected from an audible zone range to a living body. A geophone 2 receives the oscillatory wave propagating in the living body 10 at a position a prescribed distance apart from a position at which the exciter 1 has given the oscillatory wave to the living body. A search unit 3A, while varying a frequency of the oscillatory wave given to the living body 10 by the exciter 1, searches for the oscillatory wave's frequency at which a phase difference between the oscillatory wave given to the living body 10 by the exciter 1 and the oscillatory wave received by the geophone 2 is a specific phase difference. A calculation unit 3B, on the basis of the frequency having been searched by the search unit 3A, calculates the oscillatory wave's propagation speed in the living body 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a biological measurement apparatus, a biological measurement method, and a detection method.

  There are various methods for examining information inside a living body such as a human body, and X-rays, ultrasonic waves, and part of a living tissue are taken out. For example, a hardness measuring device that measures the hardness of a living body using ultrasonic waves is disclosed (for example, see Patent Document 1).

Japanese Patent No. 4287200

  The measurement of information inside the living body is desirably performed in a non-invasive and simple manner without causing exposure and pain and without placing a burden on the subject's body as much as possible. In addition, for example, ultrasonic waves are difficult to pass through the living body, and there is a limit to the range that can be measured.

  The present invention relates to a living body measuring apparatus, a living body measuring method, and a detection capable of measuring information inside a living body by a non-invasive and simple method without causing exposure and pain, and without burdening the body of the subject as much as possible. It aims to provide a method.

In order to achieve the above object, a biological measurement apparatus according to the first aspect of the present invention provides:
An excitation unit that gives a living body a vibration wave having a single frequency selected from the range of the audible range;
A vibration receiving unit that receives vibration waves transmitted through the living body at a position away from a position where the vibration unit gives the vibration wave to the living body by a predetermined distance;
While changing the frequency of the vibration wave given to the living body by the vibration unit, the phase difference between the vibration wave given to the living body by the vibration unit and the vibration wave received by the vibration receiving unit is a specific phase difference. A search unit for searching for the frequency of the vibration wave such that
A calculation unit that calculates a propagation speed of the vibration wave in the living body based on the frequency searched by the search unit;
Is provided.

In this case, a stress measurement unit that measures stress measured in a state where a spherical probe is pushed into the living body to a predetermined depth,
The calculation unit includes:
Based on the stress measured by the stress measurement unit, to calculate the Young's modulus of the living body,
It is good as well.

The calculation unit includes:
Calculating the density of the living body based on the calculated propagation velocity and the Young's modulus of the living body;
It is good as well.

The calculation unit includes:
Based on the calculated density of the living body, calculate information on the ratio of muscle tissue and / or adipose tissue in the living body,
It is good as well.

The vibrator is
Two different excitation points in the living body are respectively excited in the same phase or in opposite phase by the respective vibrators,
The geophone is
Receiving at a receiving point which is one central point of the two excitation points;
It is good as well.

The biological measurement method according to the second aspect of the present invention includes:
While the computer changes the frequency of the vibration wave applied to the living body by the vibrator in the range of the audible range, the vibration wave applied to the living body by the vibrator and the vibration wave received by the shaker A search step for searching for a frequency of the vibration wave such that the phase difference becomes a specific phase difference;
A calculation step in which the computer calculates the propagation speed of the vibration wave in the living body as information on the hardness of the living body based on the frequency searched in the searching step;
including.

In this case, using a stress strain meter that measures the stress obtained when the spherical probe is pushed into the living tissue to a predetermined depth, the measurement step includes measuring the stress,
In the calculating step,
The computer is
Based on the stress measured in the measurement step, calculate the Young's modulus of the living body,
It is good as well.

In the calculating step,
The computer calculates the density of the living body as information on the hardness of the living body based on the propagation speed and the Young's modulus of the living body.
It is good as well.

In the calculating step,
Based on the calculated density of the living body, the computer calculates information on the ratio of muscle tissue and / or adipose tissue in the living body as information on the hardness of the living body,
It is good as well.

In the search step,
Search the frequency of the vibration wave by horizontally arranging the vibrator and the geophone,
It is good as well.

In the search step,
Place the exciter and the geophone on the upper part of the breast, perform the search step and the calculation step, measure the propagation speed of the vibration wave in that part,
Placing the exciter and the geophone in the lower part of the breast and performing the search step and the calculation step to measure the propagation speed of the vibration wave in that part;
It is good as well.

In the search step,
A plurality of different excitation points in the living body are respectively excited in the same phase or in opposite phase by the vibrator,
Receiving at the geophone as a receiving point at the center of the plurality of excitation points,
It is good as well.

The detection method according to the third aspect of the present invention is:
Using the breast as a measurement target, the living body measuring method according to the second aspect of the present invention is performed to determine the propagation speed of the vibration wave in the living body, and breast cancer is detected based on the change in the propagation speed.

  According to the present invention, the distance between the excitation unit that applies a vibration wave having a single frequency in the audible range to the living body and the vibration reception unit that receives the vibration wave transmitted through the living body is set to a predetermined distance. Then, while changing the frequency of the vibration wave applied to the living body, the vibration wave such that the phase difference between the vibration wave applied to the living body by the vibration unit and the vibration wave received by the vibration receiving unit becomes a specific phase difference. Search for a frequency. In this way, since the relationship between the frequency and the wavelength of the vibration wave transmitted through the living body is known, the propagation speed of the vibration wave in the living body can be obtained. Since the propagation speed of the vibration wave in the living body changes according to the hardness of the living body, it becomes basic information for obtaining information inside the living body. As described above, according to the present invention, information inside the living body can be measured by a non-invasive and simple method without causing exposure and pain, and without burdening the body of the subject as much as possible.

It is a block diagram which shows the structure of the biometric apparatus which concerns on Embodiment 1 of this invention. FIG. 2A is a diagram showing a case where the vibration wave phase difference is 180 degrees between the vibration monitor signal and the vibration signal. FIG. 2B is a diagram showing the vibration monitor signal and the vibration signal. FIG. 6 is a diagram illustrating a case where the phase difference of the vibration wave is shifted by 540 degrees. It is a figure which shows the relationship between the frequency of a vibration wave, and the phase difference of the vibration wave of an exciter monitor signal and a vibration receiving signal. It is a flowchart which shows operation | movement of the biometric apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the biometric apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the biometric apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows operation | movement of the bioinstrumentation apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the arrangement | positioning pattern of the vibrator and geophone in a breast. FIG. 9A is an example of a phase graph in the pattern A arrangement (when the vibrator is placed on the top). FIG. 9B is an example of a phase graph in the pattern A arrangement (when the vibrator is placed below). FIG. 10A is an example of a phase graph in the arrangement of pattern C (when the vibrator is placed on the top). FIG. 10B is an example of a phase graph in the pattern C arrangement (when the vibrator is placed on the bottom). FIG. 11A is an example of a phase graph in the pattern B arrangement. FIG. 11B is an example of a phase graph in the pattern D arrangement. FIG. 12A is a schematic diagram illustrating a state in which vibration is measured at a receiving point that is separated from the excitation point by a half wavelength. FIG. 12B is a schematic diagram illustrating a state in which vibration is measured at a receiving point that is one wavelength away from the excitation point. It is a figure which shows the structure of the biometric apparatus which concerns on Embodiment 5 of this invention in the case of performing 1 point | piece excitation method. It is a figure which shows the structure of the bioinstrumentation apparatus which concerns on Embodiment 5 of this invention in the case of performing a 2-point in-phase excitation method and a 2-point anti-phase excitation method. It is a phase graph which shows the measurement result of a 1 point vibration method. It is a phase graph which shows the measurement result of a two-point in-phase excitation method. It is a phase graph which shows the measurement result of a 2 point | piece antiphase excitation method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each figure, the same components are denoted by the same reference numerals.

Embodiment 1 FIG.
As shown in FIG. 1, the biological measurement apparatus 100 according to Embodiment 1 of the present invention includes a vibrator 1, a shaker 2, and a controller 3. The living body measuring apparatus 100 measures information inside the living body 10.

  The vibrator (speaker) 1 gives a vibration wave (longitudinal wave) to the living body 10. The vibration wave given by the vibrator 1 is a vibration wave having a single frequency selected from the range of the audible range by the controller 3. As the range of the audible range, various ranges higher than 0 Hz and 20,000 Hz or lower can be set, but preferably higher than 0 Hz and 1000 Hz or lower. The vibrator 1 vibrates according to the vibration signal input from the controller 3. Thereby, a vibration wave (longitudinal wave) is transmitted through the living body 10.

  An acceleration pickup 1A is attached to the vibrator 1. The acceleration pickup 1 </ b> A detects a waveform of a vibration wave given from the vibrator 1 to the living body 10. The acceleration pickup 1 </ b> A outputs an exciter monitor signal corresponding to the detected waveform to the controller 3.

  The geophone 2 is in contact with the living body 10 at a position separated by a predetermined distance L from the position where the vibrator 1 is in contact with the living body 10. The geophone 2 is an acceleration pickup that receives vibrations given by the vibrator 1 and transmitted through the living body 10.

  The phase of the vibration wave transmitted through the living body 10 that is received by the vibration receiver 2 is delayed with respect to the phase of the vibration wave that is applied from the vibrator 1 to the living body 10. As shown in FIG. 2A, when the phase difference is 180 degrees between the vibrator monitor signal and the vibration receiving signal, the distance L between the vibration vibrator 1 and the vibration receiving body 2 is the vibration wave transmitted through the living body 10. Half wavelength (L = λ / 2). In addition, as shown in FIG. 2B, when the phase difference between the vibrator monitor signal and the vibration receiving signal is shifted by 540 degrees, the distance between the vibrator 1 and the vibration receiver 2 is transmitted through the living body 10. The half wave of the vibration wave (L = 3λ / 2). Thus, if the distance L between the vibrator 1 and the shaker 2 and the phase difference between the shaker monitor signal and the received signal are obtained, the wavelength of the vibration wave transmitted through the living body 10 can be obtained.

  Even if the distance between the shaker 1 and the shaker 2 is the same, the phase difference between the shaker monitor signal and the received vibration signal changes according to the frequency of the vibration wave. As shown in FIG. 3, as the frequency of the vibration wave increases, the vibration receiving signal is delayed with respect to the vibrator monitor signal. When the frequencies are f1, f2, and f3, the phase difference is m of 180 degrees (m is a natural number).

  The living body measurement apparatus 100 according to the present embodiment includes a distance L between the vibrator 1 and the shaker 2, a frequency of a vibration wave transmitted through the living body 10, and a phase difference between the shaker monitor signal and the received vibration signal. Based on this, the propagation velocity V of the vibration wave transmitted through the living body 10 is measured as information inside the living body. For example, the frequency f1 of the vibration wave at which the phase difference between the exciter monitor signal and the vibration receiving signal is 180 degrees is obtained. Then, based on the wavelength λ = 2L of the vibration wave at that time, the propagation velocity V of the vibration wave is obtained.

  Returning to FIG. 1, the controller 3 controls the vibrator 1 and the geophone 2 to perform the measurement. Specifically, the controller 3 outputs an excitation signal having a selected frequency to the vibrator 1, inputs a vibrator monitor signal output from the acceleration pickup 1 </ b> A, and outputs it from the receiver 2. Input vibration receiving signal. The controller 3 performs signal processing on the vibration monitor signal output from the acceleration pickup 1 </ b> A and the vibration reception signal received by the vibration receiver 2 while adjusting the vibration signal output to the vibration generator 1. Thus, information inside the living body 10 is measured.

  The controller 3 is a computer having a CPU (Central Processing Unit), a storage device, and an input / output device. The controller 3 executes the program stored in the storage device, thereby adjusting the vibration signal and performing signal processing on the vibration monitor signal and the vibration signal.

  As shown in FIG. 1, the controller 3 has a search unit 3A as a configuration of functions realized by executing a program for adjusting an excitation signal and performing signal processing on the shaker monitor signal and the received signal. And a calculation unit 3B.

  The search unit 3 </ b> A outputs an excitation signal to the vibrator 1. This excitation signal is a sinusoidal signal having a single frequency. The vibrator 1 vibrates according to the vibration signal, and transmits a vibration wave (longitudinal wave) that matches the frequency of the vibration signal to the living body 10. Search unit 3A can change the frequency of the excitation signal within the audible range. By changing the frequency of the vibration signal, the frequency of the vibration wave applied to the living body 10 by the vibrator 1 is changed.

  The search unit 3A receives the vibration monitor signal and the vibration receiving signal while changing the frequency of the vibration signal. Search unit 3A calculates the phase difference between the vibrator monitor signal and the vibration receiving signal. Search unit 3A changes the frequency of the excitation signal until the calculated phase difference becomes a specific phase difference. For example, the search unit 3A changes the frequency of the vibration wave given to the living body 10 by the vibrator 1 and the vibration wave given to the living body 10 by the shaker 1 and the vibration wave received by the shaker 2. The frequency f1 of the vibration wave is searched for such that the phase difference becomes a specific phase difference (−180 degrees).

The calculation unit 3B calculates the vibration wave propagation velocity V in the living body 10 based on the frequency searched by the search unit 3A.
V = f1 × 2L (1)

  Next, the measurement operation of the biological measurement apparatus 100 will be described.

  As shown in FIG. 4, the setting of the vibrator 1 and the geophone 2 is performed (step S1). Specifically, the exciter 1 and the geophone 2 are brought into contact with the sample (living body 10) with a predetermined distance L open.

  Subsequently, the vibrator 1 is swept from 0 Hz to 1000 Hz of the vibration wave frequency (step S2).

  Subsequently, the search unit 3A detects the phase of the exciter monitor signal and the phase of the received signal for each frequency, and detects the phase difference between the two (step S3).

  Subsequently, the search unit 3A determines the frequency f1 of the vibration wave at which the phase difference is −180 degrees (step S4).

  Subsequently, the calculation unit 3B calculates the propagation velocity V of the vibration wave using the above formula (1) (step S5). The propagation speed V of the vibration wave is information indicating the hardness of the living body 10. The greater the propagation velocity V, the harder the measurement site of the living body 10 is.

  As described above in detail, according to the present embodiment, the vibration exciter 1 that applies a vibration wave having a single frequency in the audible range to the living body 10 and the vibration receiver 2 that receives the vibration wave transmitted through the living body 10 are provided. The distance is set to a predetermined distance L. Then, while changing the frequency of the vibration wave applied to the living body 10, the phase difference between the vibration wave applied to the living body by the vibrator 1 and the vibration wave received by the vibration receiver 2 becomes a specific phase difference. Search for vibration wave frequency.

  In this way, the propagation speed V of the vibration wave in the living body 10 can be obtained based on the relationship between the distance L between the vibration exciter 1 and the vibration receiver 2, the phase difference of vibration wave 180 °, and the frequency f1. The propagation speed V of the vibration wave in the living body 10 is basic information for obtaining information inside the living body 10 that changes according to the hardness of the living body 10. As described above, according to the living body measuring apparatus 100 according to the present embodiment, the information inside the living body 10 can be obtained in a non-invasive and simple manner without causing exposure and pain, and without burdening the subject's body as much as possible. Can be measured.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described. In the present embodiment, a stress strain meter 101 shown in FIG. 5 is used in addition to the living body measuring apparatus 100 for measuring information inside the living body 10.

  As shown in FIG. 5, the stress strain gauge 101 includes a rod-shaped body 20, a stress measurement unit 21, and a pressing unit 22. The rod-shaped body 20 protrudes outward from the stress measurement unit 21, and a part of a spherical surface of a sphere having a radius R centered at the origin O is formed at the protruding tip. The stress measurement unit 21 measures the stress F when an object is pressed against the tip of the rod-shaped body 20. The pressing unit 22 is pressed against the surface of the living body 10 when the tip of the rod-shaped body 20 is pressed against the living body 10. The depth at which the tip of the rod-shaped body 20 enters the living body 10 by the pressing portion 22 is h.

  The stress F obtained when the stress strain meter 101 is pressed against the living body 10 as shown in FIG. 5 is sent to the controller 3.

In the present embodiment, the calculation unit 3B calculates the Young's modulus of the living body 10 based on the stress F. The Young's modulus E of the living body 10 is obtained using the following equation.
E = (3/4) × (F / (R ^1/2 × h ^2/3 ) × (1-σ ² ) (2)
Here, σ is a Poisson's ratio. For example, 0.490 can be used when the site to be measured is a muscle tissue, and 0.495 can be used when the site is a fat tissue.

In addition, said Formula (2) is a type | formula obtained by setting radius R 'of the to-be-contacted side to infinity based on the following well-known solid contact type | formulas.
h = F ^2/3 [D ² (1 / R + 1 / R ′)] ^1/3 (3)
Here, D = 3/4 ((1-σ) ² / E + (1-σ ′) ² / E ′). σ ′ and E ′ are the Poisson's ratio and Young's modulus of the rod-shaped body 20.

Furthermore, the calculation unit 3B calculates the density ρ of the living body 10 using the following equation based on the calculated propagation velocity V and the Young's modulus E of the living body 10 as in the first embodiment.
ρ = (a ² × E) / V ² (4)
In the above formula (4), a is a constant determined by the shape of the living body 10, the frequency of the vibration wave, and the measurement location.

  As shown in FIG. 6, the search unit 3A and the calculation unit 3B perform steps S1 to S5 as in the first embodiment. Subsequently, the stress F is measured using the stress strain meter 101 (step S6). The measured stress F is sent to the calculation unit 3B. The calculation unit 3B calculates the Young's modulus E of the living body 10 using the above equation (2) based on the stress F of the living body 10 measured by the stress strain meter 101 (step S7). Subsequently, the calculation unit 3B calculates the density ρ of the living body 10 using the above formula (4) (step S8).

  As described above, according to the present embodiment, the density ρ of the living body 10 is obtained by a non-invasive and simple method without causing exposure and pain, and placing as little burden on the subject's body as possible. Can do.

  In the present embodiment, the stress F of the living body 10 measured by the stress strain meter 101 is automatically sent to the calculation unit 3B, and the calculation unit 3B uses the stress F sent from the stress strain meter 101 to perform the Young's modulus. Although E is calculated, the present invention is not limited to this. For example, the measurer inputs the stress F measured by the stress strain meter 101 to the controller 3 by operating the input / output device, and the calculation unit 3B uses the input stress F to make the Young's modulus E. May be calculated.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described. In the present embodiment, the ratio of the adipose tissue of the living body 10 is measured.

The calculation unit 3B calculates information related to the ratio of muscle tissue and / or adipose tissue in the living body 10 based on the calculated density ρ of the living body 10 as in the second embodiment. Here, the ratio of muscle tissue is x, and the ratio of fat tissue is y. In general, since the density of muscle tissue is close to 1.06 and the density of adipose tissue is close to 0.90, the density ρ of the living body is expressed by the following equation.
ρ = 1.06x + 0.90y (5)
x + y = 1.0 (6)
From the above formulas (5) and (6), the fat tissue ratio y is expressed by the following formula.
y = (1.06-ρ) /0.16 (7)

  As illustrated in FIG. 7, the search unit 3A, the calculation unit 3B, and the like execute steps S1 to S8 as in the second embodiment. After execution of step S8, the calculation unit 3B calculates the fat tissue ratio y using the equation (6) based on the calculated density ρ (step S9).

  As described above, according to the present embodiment, the ratio y of the adipose tissue of the living body 10 is a non-invasive and simple method that does not involve exposure and pain, and places as little burden on the subject's body as possible. Can be requested.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described. In the present embodiment, the hardness of the breast is measured.

In the present embodiment, as shown in FIG. 8, the vibration exciter 1 and the vibration receiver 2 are arranged in the following several arrangement patterns, and measurement is performed. In addition, the space | interval L of the vibrator 1 and the geophone 2 is 5 cm.
Pattern A: An arrangement pattern in which the vibrator 1 and the geophone 2 are arranged in the vertical direction on the left side of the breast 30. In this case, the transmission direction of the vibration wave is the vertical direction.
Pattern B: An arrangement pattern in which the vibrator 1 and the geophone 2 are arranged in the horizontal direction above the breast 30. In this case, the transmission direction of the vibration wave is the horizontal direction.
Pattern C: An arrangement pattern in which the vibrator 1 and the geophone 2 are arranged in the vertical direction on the right side of the breast 30. In this case, the transmission direction of the vibration wave is the vertical direction.
Pattern D: An arrangement pattern in which the vibrator 1 and the geophone 2 are arranged in the horizontal direction below the breast 30. In this case, the transmission direction of the vibration wave is the horizontal direction.

  FIG. 9A shows a phase graph in the case where the vibrator 1 is on the upper side in the pattern A in a state where the posture of the subject is standing. FIG. 9B shows a phase graph when the vibrator 1 is placed on the lower side in the pattern A. As can be seen by comparing FIG. 9 (A) and FIG. 9 (B), in pattern A, the value of the frequency f1 is significantly different just by turning the vibrator 1 and the receiver 2 upside down. .

  FIG. 10A shows a phase graph in the case where the posture of the subject is standing and the pattern C and the vibrator 1 are on the upper side. FIG. 10B shows a phase graph in the case where the pattern C and the vibrator 1 are on the lower side. As can be seen by comparing FIG. 10 (A) and FIG. 10 (B), in the pattern C, the value of the frequency f1 is significantly different just by turning the vibrator 1 and the shaker 2 upside down. .

FIG. 11A shows a phase graph in the pattern B in a state where the posture of the subject is standing. In the pattern B, the value of the frequency f1 was not changed regardless of whether the vibrator 1 was on the left side or the right side, and the value thereof was substantially the same and was 44.4 Hz. At this time, the propagation velocity V is calculated as follows.
V = 0.05 × 2 × 44.4 = 4.4 m / s

FIG. 11B shows a phase graph of the pattern D in a state where the posture of the subject is standing. In the pattern D, the value of the frequency f1 did not change regardless of whether the vibrator 1 was on the left side or the right side, and the value was almost the same, 372.8 Hz. At this time, the propagation velocity V is calculated as follows.
V = 0.05 × 2 × 372.8 = 37.2 m / s

  Thus, in this Embodiment, it became clear that the direction which arrange | positioned the vibrator 1 and the geophone 2 horizontally can perform a measurement with sufficient precision.

  By the way, when measurement was performed with the pattern B while the same subject was sleeping, the frequency f1 was 74.0 Hz, and the propagation velocity V of the vibration wave was 7.4 m / s. On the other hand, when the pattern D was measured with the subject sleeping, the frequency f1 was 134.6 Hz, and the propagation velocity V was 13.5 m / s.

  From the above results, it can be seen that even if the same location is measured by the same subject, the propagation speed V of the vibration wave differs between the standing state and the sleeping state. Specifically, the measurement position of the pattern B, that is, the upper half of the breast 30, becomes softer than the posture of sleeping, and the measurement position of the pattern D, that is, the lower side of the breast 30, the sleeping posture. However, it became softer than standing. Changes in the hardness of each part of the breast 30 according to the posture of the subject are useful information for determining the shape of the underwear to be worn on the breast 30. For example, it is possible to measure the hardness of each part of the breast 30 when standing or sitting, and to make an underwear having an appropriate tightening force according to each posture.

  In addition, the biological measurement apparatus 100 according to the present embodiment can be applied to detection of breast cancer. Breast cancer tumors are known to be ten times harder than normal tissues. Therefore, the living body measuring apparatus 100 is used to observe a change in the propagation speed V of the vibration wave in the same part of the breast 30. For example, if the propagation velocity V of the vibration wave increases at a certain point in that region, it indicates that the cell tissue at that region has become hard, and thus the occurrence of breast cancer can be suspected. By performing such measurement, it becomes possible to detect breast cancer early without performing mammography examination or the like.

Embodiment 5. FIG.
Next, a fifth embodiment of the present invention will be described. Here, the principle of the method for measuring the hardness of the living body 10 in a non-destructive manner using the living body measuring apparatus 100 according to each of the above embodiments is summarized, and vibration transmission using the vibrator 1 and the shaker 2 is performed. A method variation will be described. The biological measurement apparatus 100 according to the present embodiment includes two vibrators 1. In the present embodiment, the vibrator 1 transmits not only a longitudinal wave but also a transverse wave to the living body 10.

In general, a wave propagates fast when the medium is hard, and propagates slowly when the medium is soft. This is because there is a relationship represented by the following equation (1) ′ between the wave propagation velocity V [m / s], the medium hardness (Young's modulus) E, and the density ρ.
V = C × √ (E / ρ) (1) ′
Here, the coefficient C is an expression expressed only by the Poisson's ratio in the case of a longitudinal wave and a transverse wave. Since the Poisson's ratio takes a constant value between 0.3 and 0.5 in the case of the living body 10, the coefficient C is almost constant. Further, the density ρ is a constant close to the density of water in the case of the living body 10. Since the coefficient C and the density ρ are constants as described above, the hardness E can be quantitatively evaluated by measuring the propagation velocity V from the equation (1) ′.

  There are two methods for evaluating the vibration propagation velocity V: a method of directly measuring and evaluating the vibration propagation distance l and time t, and a method of evaluating using the phase difference θ between the excitation point and the receiving point. is there. In the method of directly measuring the propagation distance l and the time t, a pulsed vibration is given at a certain period at the excitation point, and the time t when the pulse wave reaches the receiving point located at a distance l from the excitation point. Measure. However, in this method, the manufacturing cost of a pulse wave generator using ultrasonic waves or the like, or a vibration control unit and a vibration receiving unit by a computer becomes high.

On the other hand, in the evaluation method using the phase difference θ, the propagation velocity V [m / s] is obtained using the following equation (2) ′.
V = 360 × f × l / θ (2) ′
Here, f [Hz] is the frequency, and l [m] is the distance between the excitation point and the receiving point. Θ [°] is a phase difference obtained by subtracting the vibration phase at the receiving point of the shaker 2 from the vibration phase at the excitation point of the shaker 1. Here, for example, when the phase difference between the excitation point and the receiving point is 180 degrees, the vibration at the receiving point separated by a half wavelength from the excitation point is measured as shown in FIG. When the phase difference between the excitation point and the receiving point is 360 degrees, as shown in FIG. 12B, the vibration at the receiving point that is separated from the excitation point by one wavelength is measured.

  Thus, in the method using the phase difference θ between the vibration at the excitation point and the vibration received at the receiving point, it is only necessary to give the living body 10 a sine wave mechanical vibration within the audible range (20 to 7000 Hz). Since the structure of the apparatus can be simplified, it is possible to make it difficult for the apparatus to fail and to reduce the manufacturing cost of the apparatus. Further, since the sine wave is continuously given from the excitation point of the vibrator 1, the Fourier transform (FFT) can be stably executed, and the detection accuracy of the phase difference θ can be improved. Therefore, living body measuring apparatus 100 according to the present embodiment measures phase difference θ under a constant frequency f and distance l.

  In order to improve the vibration receiving sensitivity, the living body measurement apparatus 100 according to the present embodiment measures the propagation speed of vibration between vibrations using one of the following three methods according to the characteristics of the living body 10. Evaluate hardness. The biological measurement apparatus 100 includes two vibrators 1.

(1) One-Point Excitation Method As shown in FIG. 13, this is a method in which one exciter 1 is used to excite at one point and the receiver 2 receives the signal at one point. This method can measure the hardness of each measurement location when the hardness of the living body 10 changes depending on the position, that is, when the hardness is non-uniform.

(2) Two-point in-phase excitation method As shown in FIG. 14, two different excitation points are excited in the same phase using two excitation units 1, and one center point of the two excitation units 1. Is received by the geophone using the geophone as a receiving point. When the two excitation points are excited in the same phase, the transverse wave generated at the excitation point becomes easy to receive due to the increased amplitude of the transverse wave at the receiving point due to the principle of wave superposition. However, since the longitudinal wave generated at the excitation point is canceled out at the receiving point, this method is not suitable for measuring the propagation velocity using the longitudinal wave. In addition, when the hardness between the two excitation points is uniform, the vibration is easily received. When the hardness is not uniform, the vibration waves reach the reception point at different propagation velocities from the excitation point. As a result, the measurement accuracy of the propagation velocity V decreases.

(3) Two-point anti-phase excitation method As shown in FIG. 14, two different excitation points are excited in opposite phases using two vibrators 1, and the center 1 of the two vibrators 1 is In this method, the point is received by a receiving device with the receiving point as a receiving point. When the two excitation points are excited in opposite phases, the longitudinal wave generated at the excitation point increases the amplitude of the longitudinal wave at the reception point and is easy to receive. On the other hand, the transverse wave generated at the excitation point is canceled at the receiving point. When longitudinal waves that are easy to receive vibrations are used, when a tissue having different hardness is locally present in the living body 10 in the vicinity of directly under the vibration receiver, a part of the vibration is reflected by the tissue having different hardness and the propagation velocity V Changes. Therefore, it is possible to find tissues having different hardnesses by observing changes in the propagation velocity V while changing the positions of the excitation point and the receiving point. Further, when the hardness between the two excitation points is not uniform, the measurement accuracy of the propagation speed is deteriorated for the same reason as in (2).

The characteristics of the methods (1), (2), and (3) are summarized as shown in the following table. As described above, it is desirable that the one-point excitation method, the two-point in-phase excitation method, and the two-point anti-phase excitation method are properly used according to the state of the living body 10. When the state of the living body 10 is unknown, it is desirable to perform measurement by all of the one-point excitation method, the two-point in-phase excitation method, and the two-point anti-phase excitation method.

  The vibration speed of the agar propagation velocity V assumed to be the tissue of the living body 10 was measured using the above three methods. The agar was prepared as a rectangular parallelepiped 7 cm long, 16 cm wide and 4 cm high.

  In the one-point excitation method, the excitation point and the reception point were placed at points 5 cm away from the center to the end of the upper surface of the rectangular parallelepiped. In the two-point in-phase excitation method and the two-point anti-phase excitation method, the receiving point was placed at the center of the rectangular parallelepiped upper surface, and the two excitation points were placed at points 2.5 cm away from the center. And vibration to 1000 Hz was given to the agar at the excitation point. 15, 16, and 17 show the results obtained by applying vibration to the agar by three methods of the one-point excitation method, the two-point in-phase excitation method, and the two-point anti-phase excitation method.

  The distance of 2.5 cm between excitation and reception in the two-point in-phase / anti-phase excitation method is half that in the one-point excitation method, so the phase difference is expected to be halved from equation (2). Is done. Actually, the phase difference of the two-point in-phase / anti-phase excitation method (see FIGS. 16 and 17) measured between 0 [Hz] and 1000 [Hz] is the phase difference of the one-point excitation method. It was found that it was almost half of that (see FIG. 15). In the two-point in-phase excitation method, a transverse wave is measured at the receiving point, and in the two-point anti-phase excitation method, a longitudinal wave is measured at the receiving point. In both cases, if the distance between excitation and reception is the same, the phase difference is expected to be the same from equation (2). Actually, it was found that the measured phase difference of the two-point in-phase excitation method (see FIG. 16) was the same as the phase difference of the two-point anti-phase excitation method (see FIG. 17).

  As described above, according to the present embodiment, the hardness of each part of the breast 30 can be obtained in a non-invasive and simple manner without causing exposure and pain, and placing as little burden on the subject as possible. Can be requested.

  In each of the above embodiments, the computer searches for a frequency at which the phase difference is 180 degrees, but the present invention is not limited to this. For example, a frequency where the phase difference is 90 degrees or 270 degrees may be searched.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope of the present invention. The above-described embodiments are for explaining the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

  The present invention can be applied to measuring in vivo information.

  DESCRIPTION OF SYMBOLS 1 Exciter, 1A Acceleration pick-up, 2 Geophone, 3 controller, 3A search part, 3B calculation part, 10 biological body, 20 stick-shaped body, 21 stress measurement part, 22 pressing part, 30 breast, 100 biological measurement apparatus, 101 Stress strain gauge.

Claims (13)

An excitation unit that gives a living body a vibration wave having a single frequency selected from the range of the audible range;
A vibration receiving unit that receives vibration waves transmitted through the living body at a position away from a position where the vibration unit gives the vibration wave to the living body by a predetermined distance;
While changing the frequency of the vibration wave given to the living body by the vibration unit, the phase difference between the vibration wave given to the living body by the vibration unit and the vibration wave received by the vibration receiving unit is a specific phase difference. A search unit for searching for the frequency of the vibration wave such that
A calculation unit that calculates a propagation speed of the vibration wave in the living body based on the frequency searched by the search unit;
A biological measurement apparatus comprising: A stress measuring unit that measures stress measured in a state where a spherical probe is pushed into the living body to a predetermined depth;
The calculation unit includes:
Based on the stress measured by the stress measurement unit, to calculate the Young's modulus of the living body,
The biological measurement apparatus according to claim 1. The calculation unit includes:
Calculating the density of the living body based on the calculated propagation velocity and the Young's modulus of the living body;
The biological measurement apparatus according to claim 2. The calculation unit includes:
Based on the calculated density of the living body, calculate information on the ratio of muscle tissue and / or adipose tissue in the living body,
The biological measurement apparatus according to claim 3. The vibrator is
Two different excitation points in the living body are respectively excited in the same phase or in opposite phase by the respective vibrators,
The geophone is
Receiving at a receiving point which is one central point of the two excitation points;
The biological measurement apparatus according to claim 1. While the computer changes the frequency of the vibration wave applied to the living body by the vibrator in the range of the audible range, the vibration wave applied to the living body by the vibrator and the vibration wave received by the shaker A search step for searching for a frequency of the vibration wave such that the phase difference becomes a specific phase difference;
A calculation step in which the computer calculates the propagation speed of the vibration wave in the living body as information on the hardness of the living body based on the frequency searched in the searching step;
A biological measurement method including: A measurement step of measuring the stress using a stress strain meter that measures the stress obtained when the spherical tissue probe is pushed into the living tissue to a predetermined depth;
In the calculating step,
The computer is
Based on the stress measured in the measurement step, calculate the Young's modulus of the living body,
The biological measurement method according to claim 6. In the calculating step,
The computer calculates the density of the living body as information on the hardness of the living body based on the propagation speed and the Young's modulus of the living body.
The biological measurement method according to claim 7. In the calculating step,
Based on the calculated density of the living body, the computer calculates information on the ratio of muscle tissue and / or adipose tissue in the living body as information on the hardness of the living body,
The biological measurement method according to claim 8. In the search step,
Search the frequency of the vibration wave by horizontally arranging the vibrator and the geophone,
The biological measurement method according to any one of claims 6 to 9. In the search step,
Place the exciter and the geophone on the upper part of the breast, perform the search step and the calculation step, measure the propagation speed of the vibration wave in that part,
Placing the exciter and the geophone in the lower part of the breast and performing the search step and the calculation step to measure the propagation speed of the vibration wave in that part;
The biological measurement method according to claim 10. In the search step,
A plurality of different excitation points in the living body are respectively excited in the same phase or in opposite phase by the vibrator,
Receiving at the geophone as a receiving point at the center of the plurality of excitation points,
The biological measurement method according to claim 6. The biological measurement method according to any one of claims 6 to 12 is performed on a breast as a measurement target, a propagation speed of the vibration wave in the living body is obtained, and breast cancer is determined based on a change in the propagation speed. To detect,
Detection method.

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