JP2003210460A - Shearing modulus measuring device and therapeutic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the shearing modulus of a region of interest of an organism even in the presence of other force sources or an uncontrollable force source in a measured object. <P>SOLUTION: This shearing modulus measuring device is provided with a storage means 2 storing distorted tensor field data measured on a region of interest 7 set to the measured object, and a shearing elastic modulus computing means 1 for computing the shearing modulus of an optional point in the region of interest on the basis of the distorted tensor field data. The shearing modulus computing means computes the shearing modulus of the region of interest, regarding all force sources as positioned outside the region of interest by obtaining the shearing modulus by a numerical analysis on the basis of a first- level partial differential equation indicating the relation between the distorted tensor field and the shearing modulus, that is, by measuring the shearing modulus only on the region of interest as an object. A value preset by measurement or the like is used as Poisson's ratio required for operation, and a reference shearing modulus is used as the initial condition of solving the partial differential equation. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for nondestructively quantitatively measuring internal mechanical characteristics of an object to be measured such as an object, a substance, a material, or a living body. The present invention relates to a technique in which a force is applied to an object by a force source such as a power source, a displacement distribution or a strain tensor field generated inside the object is measured by the force, and a shear elastic modulus is obtained based on the strain tensor field.

As a typical application field, in a medical field such as an ultrasonic diagnostic apparatus for observing the inside of a living body, a magnetic resonance imaging apparatus, a radiotherapy, etc., a means for monitoring the degeneration of a tissue which is a therapeutic effect of a region of interest in a living body. Applied to. However, the present invention is not limited to this, and can be applied to the evaluation, inspection, diagnosis, etc. of the shear modulus of elasticity of an object nondestructively.

[0003]

2. Description of the Related Art For example, in the medical field, it has been proposed to treat a lesion by radiation treatment, intense ultrasonic irradiation, laser irradiation, electromagnetic RF wave irradiation, electromagnetic microwave irradiation, or the like. In this case, it has been proposed to monitor the therapeutic effect non-invasively. In addition, it has been proposed to non-invasively observe the effects of drug administration such as anticancer agents. For example, the temperature of the lesion changes when radiotherapy is performed. Therefore, if the temperature change (denaturation) can be measured non-invasively, the therapeutic effect can be monitored.

By the way, it is known that the temperature of a region of interest on an object correlates with the shear elastic modulus of the region. Therefore, if the shear modulus inside the object can be measured nondestructively, the temperature or temperature distribution of the region of interest can be measured. Here, the shear elastic modulus is a physical quantity also called shear elastic modulus, and is known to be expressed by shear elastic modulus = shear stress / shear = shear stress / shear strain.

Conventionally, as a method for measuring the shear elastic modulus,
For example, the measurement target is positively deformed while changing the position of the force source that exerts a force on the measurement target, and the stress and strain are measured at a plurality of points on the target surface each time, and based on this measurement result. It has been proposed to estimate the shear elastic modulus of a lesion area that is a region of interest. That is, the stress and strain at multiple points on the surface of the object are measured using a stress meter or displacement meter, and the shear modulus distribution is calculated based on the sensitivity theory using numerical analysis methods such as the finite difference method and the finite element method. presume.

The shear modulus of elasticity can be used not only for monitoring the effect of treatment but also for observing the difference between diseased tissue such as liver cancer and normal living tissue from the outside in a non-invasive manner. Applicable.

Further, as another monitoring technique, a method of measuring the temperature or temperature distribution of the region of interest based on the measurement of physical properties such as nuclear magnetic resonance frequency, electrical impedance, ultrasonic wave propagation velocity, etc. of the region of interest. There is. However, according to these techniques, when measuring temperature,
Other relevant physical property values for the region of interest are needed. In particular, when the site of interest is denatured, the related physical property value may change significantly, and thus there is a limit to the temperature measurement of the site that is irreversibly changed.

[0008]

When measuring the shear modulus by the conventional technique, it is necessary to positively generate a plurality of deformation fields by providing a force source on the outer surface of the object. However, if another force source exists in the object or a force source that cannot be controlled exists, it is difficult to obtain the shear elastic modulus. That is, according to the conventional technology, parameters such as position, direction of force and magnitude of force are required for all force sources, and stress and strain data of the object surface are required. It is difficult to obtain the parameters and data of. As a result, according to the conventional technique, it is necessary to model the entire object by the finite difference method or the finite element method. In addition, when treatment of the lesion site with intense ultrasonic irradiation, laser irradiation, electromagnetic RF wave irradiation, electromagnetic microwave irradiation, etc. occurs, tissue degeneration and changes in the tissue component weight fraction that accompany the structural change of the lesion tissue occur. There is.
However, in the conventional technique, measurement of tissue degeneration and changes in tissue component weight fraction are hardly considered.

An object of the present invention is, for example, to diagnose or treat a region of interest in a living body even if another force source exists in the object to be measured or a force source that cannot be controlled exists. It is to provide a technique for measuring shear modulus applicable to monitoring such as.

Another object of the present invention is to provide a minimally invasive treatment technique equipped with shear elastic modulus measuring means.

[0011]

The present invention solves the above problems by the techniques described below.

The present invention is based on the premise that the shear modulus of elasticity is measured only for the region of interest set on the measurement object. As a result, it can be considered that all force sources are located outside the region of interest. Therefore, in addition to the force source for measurement, the shear elastic modulus of the region of interest can be calculated even if there are other force sources or uncontrollable force sources. It can be measured. As a result, parameters such as position, direction of force and magnitude of force, or stress and strain data on the surface of the object are not required for all force sources, and the model is finite difference method or finite element method. Only the region of interest needs to be converted. If a force source that deforms the region of interest exists near the region of interest, it is not necessary to prepare a special force source that causes the deformation. In the case of living body observation, for example, heartbeat,
Includes uncontrolled force sources such as breathing, blood vessels, and body movements.
In this case, the shear modulus can be obtained without disturbing the lift. In particular, it is useful when setting a region of interest in a deep part of an object, which is considered to be difficult to generate a large deformation that exceeds the measurement accuracy.

Further, the shear elastic modulus is obtained by calculation based on the measured strain tensor of the region of interest. The strain tensor is measured by using a force source that is a pressure source or a vibration source to positively deform the strain tensor, or by using a natural force source to measure the deformation using a displacement or strain sensor. . An ultrasonic oscillator or a magnetic field detecting element can be used as the displacement or strain sensor. The ultrasonic transducer is a well-known element in an ultrasonic diagnostic apparatus, and an ultrasonic probe is arranged on the outer surface of an object by contact or non-contact,
The ultrasonic probe irradiates the inside of the object with ultrasonic waves, receives the echo returning from the region of interest to the probe by reflection, etc., and changes the state such as displacement in the region of interest based on the echo signal. Is to detect. In particular, when measuring the displacement vector, ultrasonic waves are radiated into the object multiple times with a time interval, and based on the gradient of the phase of the cross spectrum of the echo signals acquired in the two temporal phases, The displacement vector of any point of is calculated. The strain tensor field is obtained by differentiating the obtained displacement vector. Further, when the ultrasonic probe is used as a displacement or strain sensor and the region of interest is deformed by the applied ultrasonic waves, it is not necessary to provide a special force source that deforms the region of interest.

The shear elastic modulus measuring apparatus according to the present invention calculates the shear elastic modulus or the shear elastic modulus distribution based on the strain tensor field data obtained as described above. Specifically, the storage means storing the strain tensor field data measured for the region of interest set in the measurement object, and the shear modulus of elasticity of any point in the region of interest based on the strain tensor field data. And a shear elastic modulus calculating means for calculating the shear elastic modulus based on a first-order partial differential equation representing a relationship between the strain tensor field and the shear elastic modulus by a numerical analysis. Characterized by seeking.

When applied as a monitor for treating a lesion area of a living body non-invasively, a region of interest is set to a site including the lesion portion of the living body, and an arbitrary region is set based on strain tensor data measured for this region of interest. Output means is provided for calculating the shear elastic modulus of the point and outputting the degeneration information of the site including the lesion based on the calculated shear elastic modulus.

In the above case, when the Poisson's ratio of the object in the region of interest is related to the first-order partial differential equation, the Poisson's ratio of a pre-measured value or a preset value is used.

The reference shear modulus can be used as an initial condition for solving the first-order partial differential equation. In this case, a reference object or reference region whose elastic modulus is known in advance is set or set in or near the original region of interest,
A continuous region including this is set as a region of interest to be analyzed.
When the strain tensor field of the region of interest set in this way is obtained by measurement, the displacement vector of the reference object or the reference region is measured at the same time, and the reference shear elastic modulus is set based on this. It is preferable that the reference object or the reference region is set to a size or position that widely intersects with the deformation direction generated by the force source. For example, in the case of a force source having a large contact area, it is preferable to set a reference region having a size corresponding to the area. Further, even in the case of a force source having a small contact area, if the reference region is arranged near the surface close to the force source, there is no problem even with a relatively small reference region.
However, the present invention is not limited to this, and when the shear elastic modulus of the region of interest in a normal case can be estimated, the estimated value may be set as the reference shear elastic modulus. In any case, according to the present invention, the relative shear elastic modulus with respect to the reference shear elastic modulus can be obtained.

The finite difference method or the finite element method can be used as a numerical analysis method for solving the first-order partial differential equation. In this case, by using a regularized algebraic equation, even if the strain tensor field data contains errors (noise), the reference object or reference region is small, or the position is poor, the shear modulus The distribution can be estimated.

The shear elastic modulus measurement of the present invention is applied when measuring the shear elastic modulus or shear elastic modulus distribution in one-dimensional, two-dimensional and three-dimensional regions, and the dimension of the strain tensor to be measured is the dimension of the region. Less than a few.

The ultrasonic therapy apparatus of the present invention comprises a therapeutic oscillator in which a plurality of oscillators are arranged, and a therapeutic wave transmission circuit for outputting an ultrasonic wave drive signal to each oscillator of the therapeutic oscillator. ,
An ultrasonic probe in which a plurality of transducers are arranged, a transmission circuit for outputting an ultrasonic wave drive signal to the ultrasonic probe, and an echo signal output from the ultrasonic probe A wave receiving circuit for phasing processing, a shear elastic modulus calculating means for calculating a shear elastic modulus based on an echo signal phased by the wave receiving circuit, and the lesion part based on the calculated shear elastic modulus. Output means for outputting the degeneration information of the site containing the, a control section for controlling the therapeutic wave transmission circuit, the wave transmission circuit, the wave receiving circuit, and the shear elastic modulus calculation means, and an operation command is input to the control section. And a control unit that controls the transmitting circuit and the receiving circuit based on an operation command input from the operating unit to set a region of interest set in the living body of the subject. Deformation function and control of the therapeutic wave transmission circuit from the therapeutic oscillator And a function of controlling an ultrasonic beam to be emitted, the shear elastic modulus computing means captures an echo signal relating to the deformation of the region of interest based on a command given from the control unit, The strain tensor data is calculated, and the shear elastic modulus of the region of interest is calculated based on the strain tensor data.
The control of the ultrasonic beam for treatment is appropriately applied by controlling the beam focus position (irradiation position), the treatment execution interval, the ultrasonic beam power, the irradiation time, the beam shape (apotization) and the like.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows an overall block configuration diagram of a shear modulus measuring apparatus to which shear modulus measurement of one embodiment of the present invention is applied. This apparatus measures the shear elastic modulus distribution in the three-dimensional (two-dimensional or one-dimensional) region of interest 7 of the measurement object 6. The displacement / strain detection sensor 5 is provided in contact with the surface of the measurement object 6 or via an appropriate medium. In the present embodiment, a one-dimensional or two-dimensional array type ultrasonic probe including a plurality of ultrasonic transducers is used as the displacement / strain detection sensor 5.

The displacement / strain detection sensor 5 can mechanically adjust the distance from the object 6 to be measured by the position adjusting means 4. Further, the position adjusting means 4 ′ for mechanically adjusting the relative distance between the displacement / strain detecting sensor 5 and the measuring object 6.
Is provided. An ultrasonic transmitter and an ultrasonic pulser for driving the displacement / strain detection sensor 5, and a driving / output adjusting means 5 ′ having a receiver and an amplifier for receiving an echo signal output from the displacement / strain detection sensor 5 are provided. Has been. Further, a force source 8 such as a pressure / vibrator used when the object 6 is positively deformed, and a position adjusting means 4 "for mechanically determining the position thereof are provided. The echo signal recorded in 1 is read by the data processing means 1, and the strain tensor field in the region of interest 7 at any time is directly obtained by calculation.
When the displacement vector field in the region of interest 7 is calculated, the strain tensor component distribution is calculated by three-dimensional, two-dimensional, or one-dimensional differential filtering. The shear elastic modulus distribution is calculated from the strain tensor component thus measured. The results of these calculations are recorded in the data recording means 2.

The measurement control means 3 controls the data processing means 1, the position adjusting means 4, the position adjusting means 4 "and the drive / output adjusting means 5 '.
If the measurement object 6 is fixed, the position control means 4'is not necessary. If the displacement / strain detection sensor 5 is an electronic scanning type, the position adjusting means 4 is not always necessary. That is, depending on the size of the region of interest 7, measurement may be possible without performing mechanical scanning. Further, the displacement / strain detection sensor 5 measures the object 6 by directly contacting it with the object 6, and when the therapeutic effect is monitored when performing a high-intensity ultrasound (HIFU) treatment, the object 6 is placed in the liquid tank 9. Immerse in
It is also possible to immerse the strain detection sensor 5 in the liquid tank 9 and perform non-contact measurement.

The position adjusting means 4 mechanically positions the displacement / strain detecting sensor 5 and the object 6 relative to each other, as shown in FIG. 3, for example, and performs vertical and horizontal translation, rotation, and fan-shaped rotation. A mechanical scanning mechanism is used. Also,
The output of the drive / output adjusting means 5'is continuous in time,
Alternatively, it is recorded in the data recording means 2 at a predetermined interval. The data processing means 1 controls the driving / output adjusting means 5 ', and the fundamental wave (n = 1) of the echo signal in the three-dimensional region of interest 7 (or the two-dimensional region of interest or the one-dimensional region of interest), Acquire the nth harmonic (n = 2 to N) or all components and perform the data processing described below to obtain the desired displacement /
The strain data is obtained and stored in the data recording means 2.

The drive / output adjusting means 5 ′, in accordance with a command from the data processing means 1, transmits fixed focusing processing or multi-transmission fixed focusing processing and reception dynamic processing for ultrasonic signals transmitted / received to / from the displacement / strain detection sensor 5. An aperture synthesizing process for performing the focusing process of the focusing process is performed. Further, with respect to the ultrasonic signal, while performing apodization, for example, while performing a process of weighting the ultrasonic signal emitted from each element in order to sharpen the beam shape of the ultrasonic beam,
Beam steering processing is performed to obtain echo signals in the three-dimensional (or two-dimensional or one-dimensional) region of interest 7.

Here, the calculation contents of the shear elastic modulus in the data processing means 1 will be described. When the measurement data of the three-dimensional strain tensor is obtained, the shear elastic modulus in the three-dimensional (Cartesian coordinate system (x, y, z)) region of interest is μ, and the strain tensor field is ε. The simultaneous first-order partial differential equation of 1) holds.

[0027]

[Equation 1] Ν in the equation (1) is a Poisson's ratio. Poisson's ratio ν
Can use a measured value or a typical value of the object as the set value.

When the measurement data of the two-dimensional strain tensor is obtained, the simultaneous first-order partial differential equation of the following equation (2) or (2 ') is established. Equation (2) is a state close to plane strain, and equation (2 ′) is a state close to plane stress.

Now, assuming that the object is incompressible and the Poisson's ratio ν = 1/2, the simultaneous first-order partial differential equations of equation (2 ″) are established.

[0030]

[Equation 2] Further, when the measurement data of the one-dimensional strain tensor is obtained, the first-order partial differential equation of the following expression (3) is established.

[0031]

[Equation 3] Depending on the measured strain tensor, one of the equations (1) to (3), or a plurality of equations, has one to three dimensions.
This holds at each interest point in the dimensional interest area 7. Also,
When the measurement data of a plurality of independent strain tensor fields are obtained, the equations that are simultaneous equations are established. However, each strain (tensor) distribution data used at that time is normalized by the square root of the power of each strain (tensor) distribution. Here, the plurality of independent strain tensor fields mean a deformation field that occurs when the positions of the force source and the reference region are different. For example, when the state of the force source changes over time and is uncontrollable, or when the state of the force source is positively changed, the direction in which the force acts and the magnitude of the force change. become. Therefore, the reference region should be appropriately set according to the criteria described above for each strain tensor field.

The distribution of the Poisson's ratio ν is, for example, the ratio of the principal values of the strain tensor measured at each position (for example, in the case of three-dimensional measurement, one of the two principal values obtained,
Alternatively, it can be estimated approximately from the average value).
In particular, when a plurality of strain tensor fields are measured, it is possible to approximate the average value of the Poisson's ratio evaluated from each strain tensor. The main value itself is obtained, for example, by performing a singular value analysis on the average value.

The reference shear modulus, which is the initial condition, is
It only has to be given at one point in the region,
In the case of a region, it should be as wide as possible to improve the measurement accuracy.
It is desirable to be given in the area. Place for three-dimensional measurement
If two-dimensional measurement and primary source measurement,
The reference region ω is expressed by the following equations (4), (5) and (6), respectively. _l
Given at (l = 1 to N).

[0034]

[Equation 4] Next, we derive a regularized algebraic equation to calculate the shear modulus. First, regarding the first-order spatial partial differential equation and its initial conditions, the discrete Cartesian coordinate system (x, y, z) ~
(IΔx, JΔy, KΔz) is applied to the unknown shear modulus distribution or strain (displacement) distribution by applying the finite difference approximation or the Galerkin method or the finite element approximation based on the variational principle. Derive the algebraic equations. For example, when finite difference approximation is applied, the simultaneous equations of the following equation (7) are obtained.

E G s = e (7) where s is a vector representing the spatial distribution of the unknown shear modulus,
G is a matrix composed of finite difference approximation constants of the first partial differential, and E and e are a matrix and a vector determined from the strain tensor distribution data and its spatial differential value, respectively.

Equation (7) is solved using the least squares method. In this case, in order to reduce the noise of the measured distortion tensor data, E and e are determined by the distortion distribution and its spatial differential value subjected to a low-pass filter. As a result, the inverse operators of E and G amplify the high frequency band noise included in e. That is, s has an unstable result.
Therefore, the so-called regularization method is applied to stabilize the reconstruction. Specifically, the regularization parameters α1 and α2
Using (positive value), the functional of the following equation (8) is minimized with respect to s. Here, the superscript T means a transposed matrix.

Error (s) = | e−EG s | ² + α1 | G s | ² + α2 | G ^T G s | ² (8) where G s and G ^T G s are spaces of unknown shear modulus, respectively. The slope of the distribution and the Laplacian. G s and G ^T G
Since s is a positive definite value, error (s) always has one minimum value. By minimizing error (s),
The regularized regular equation shown in (9) is obtained.

G ^T (E ^T E + α1I + α2G G ^T ) G s = G ^T E ^T e (9) Therefore, the solution is the following formula (10). Here, I is an identity matrix.

S = (G ^T (E ^T E + α1I + α2G G ^T ) G) ^-1 G ^T E ^T e (10) Note that the same applies when the Galerkin method or the finite element approximation based on the variational principle is applied. In addition, regularization is applied to the derived simultaneous equations when the least squares method is applied. However, in this case, in equation (8), the regularization parameter α0
(Positive value) can be used to add α0I and then regularize.

The regularization parameters α0, α1 and α2 can be set as follows depending on the measurement accuracy of strain, the state of deformation, the relative position of the force source and the reference space / region. In the regularized regular equation (9),
The power of the strain tensor distribution data used so that the matrix of the vector s representing the shear elastic modulus distribution is sufficiently positive definite numerically, that is, the determinant of each strain tensor in the region of interest (the third Invariant) can be adjusted to a larger value. Alternatively, it can be adjusted according to the accuracy (SN ratio) of the strain tensor distribution data used.
For example, it is set small when the SN ratio is high and set large when the SN ratio is low. According to this, for example, it can be made inversely proportional to the SN power ratio.

The regularization parameters α0, α1, and α2 depending on the power of these strain tensor distributions are the regularization parameter values evaluated from the strain tensor distribution data when a plurality of strain tensor distribution data are used. The value is proportional to the sum. According to this, for example, the sum may be a value inversely proportional to the SN power ratio of the strain tensor distribution data.

The regularization parameters α1 and α2 may be realized as different (direction-dependent) for each direction of the partial differential appearing in the gradient operator and the Laplacian operator. To ensure that the matrix of the vector s representing the shear modulus distribution is sufficiently positive definite numerically,
In order to adjust by the power of the principal value distribution data of the strain tensor distribution used, the regularization parameter (the principal value is large, the principal value is small, the principal value is small, Is larger in the direction of the principal axis, and in accordance with this, for example, it may be set so as to be inversely proportional to the square of the principal value.) And then obtain an approximation of the partial differential operator in each direction To use the averaged value within the area, or to adjust according to the accuracy (SN ratio) of the principal value distribution data of the strain tensor distribution used,
Regularization parameters are approximated by approximating the partial differential operator in each principal axis direction with respect to the strain tensor of each interest point (the principal axis direction with a high SN ratio of the principal value is small, and the principal axis direction with a low SN ratio of the principal value is large, , For example, it may be inversely proportional to the SN power ratio of the principal value data.), And an approximation of partial differential operators in each direction is obtained, and the average of each in the region of interest can be used. In addition, when the number of measured principal values is smaller than the dimension of the region of interest, that is, when the principal value is regarded as zero numerically, the regularization parameter in the direction in which the principal value is regarded as zero is different from other regularization parameters. It can be set to a larger value than the regularization parameter in the direction of the obtained principal value. A regularization parameter α1, which depends on these directions,
When α2 is realized when multiple strain tensor distribution data are used, the product of the regularization parameter and the approximation of the partial differential operator in each direction shall be evaluated, and the power of each strain tensor distribution data used And the regularization parameter value evaluated from the accuracy, and the approximation of the partial differential operator in each direction evaluated from each strain tensor distribution data used It can be a proportional value.

Further, the regularization parameters α0, α1, α2
May be realized as something that changes spatially,
As a result, the power of the strain tensor data used at each interest point, that is, the matrix of each strain tensor, so that the local matrix of the shear modulus of each interest point becomes sufficiently positive definite numerically It can be adjusted to a larger value in the equation (third invariant). Alternatively, it can be adjusted according to the accuracy (SN ratio) of the strain tensor data used at each interest point (small when the SN ratio is high, and large when the SN ratio is low). According to this, for example, it may be inversely proportional to the SN power ratio.

The regularization parameters α0, α1, and α2 depending on the positions of these interest points are the strain tensors used at each interest point when a plurality of strain tensor data are used at the same interest point. The value is proportional to the sum of the regularization parameter values evaluated from the data. According to this, for example, the sum is a value that is inversely proportional to the SN power ratio of the distortion tensor data of each interest point. Also, when the number of strain tensor data used at each interest point is different, this number of data may be taken into consideration (large for large number of interest points, small for small number of interest points). For example, it may be proportional to the number of strain tensor data used. Also, in accordance with this, the regularization parameter value evaluated from the power and accuracy (SN ratio) of the distortion tensor data used at each interest point and the number of distortion tensor data used at each interest point are evaluated. The value of the regularization parameter to be used can be a value proportional to the sum of products calculated after weighting the importance.

Regarding the regularization parameters α1 and α2, those that spatially change as described above and that differ depending on the direction of the partial differential appearing in the gradient operator and the Laplacian operator (the one that depends on the direction) ) May be realized as. As a result, the local matrix of the shear modulus of each interest point should be adjusted by the power of the principal value data of the strain tensor used at each interest point so that the local matrix of the shear modulus becomes a positive definite value in numerical analysis. For each strain tensor used at each point of interest, a regularization parameter is approximated to the approximation of the partial differential operator in each main axis direction (a main axis direction with a large main value is small, a main axis direction with a small main value is large, and, for example,
It may be set to be inversely proportional to the square of the principal value. )
The approximation of the partial differential operator in each direction obtained by multiplying by is used. Or, in order to adjust according to the accuracy (SN ratio) of each strain tensor data used at each interest point, a regularization parameter is approximated by approximating the partial differential operator in each main axis direction for each strain tensor used at each interest point. (The main axis direction with a high main value SN ratio is small, and the main axis with a low main value SN ratio is large, and in accordance with this, for example, it can be made inversely proportional to the SN power ratio of the main value data.). An approximation of the partial differential operators in each direction obtained above can be used. When the number of measured principal values is smaller than the dimension of the region of interest, that is, when the principal value is considered to be zero in the numerical analysis, the regularization parameter for that direction is a regularity in the direction of the other principal values to be obtained. It can be set to a large value compared to the conversion parameter.

When the regularization parameters α1 and α2 depending on the position of these points of interest and on the direction are realized when a plurality of strain tensor data measured at each point of interest are used, the regularization parameters α1 and α2 are regular. The product of the generalization parameter and the approximation of the partial differential operator in each direction shall be evaluated, and the regularization parameter value evaluated from the power and accuracy of each distortion tensor data used at each interest point and each interest point It is possible to make the approximation of the partial differential operator in each direction evaluated from each strain tensor data used as a value proportional to the sum of products calculated after weighting the importance. Also, if the number of strain tensor data used at each interest point is different, this number of data may be taken into consideration (large for large number of interest points, small for small number of interest points). , For example, it may be proportional to the number of strain tensor data used. According to this, it is evaluated from the regularization parameter value evaluated from the power and accuracy (SN ratio) of the strain tensor data used at each interest point, and from each strain tensor data used at each interest point. Proportional to the sum of products calculated by weighting the approximation of the partial differential operator in each direction and the regularization parameter value evaluated from the number of strain tensor data used at each interest point It may be set to a value.

Further, the regularization parameters α0, α1, α2
Can be set to a larger value as it moves away from the reference area in the direction in which it is predominantly deformed.

In particular, in the case of one-dimensional measurement, the partial differential equation is analytically solved to obtain a relative shear elastic modulus value μ (X) / at x = X with respect to the shear elastic value at the reference point x = A. It can be confirmed that μ (A) evaluates the ratio ε (A) / ε (X) of the strains at the two points (JP-A-7-55775). However, at points or areas where the distortion value is numerically zero, or where the sign is reversed, it is stable by applying the above regularization using the relative value around the area evaluated in advance from the distortion ratio as a reference value. It can also be evaluated.

In the case of one-dimensional or two-dimensional measurement,
As the position of the interest point moves away from the force source, the shear elastic modulus at that position tends to be evaluated smaller. In this case, a model in which the object to be measured has the same shape and the shear modulus is homogeneous and the force source used is modeled, and the shear modulus distribution is calculated using strain data evaluated analytically or numerically in this model. Correct the strain measurement data used for the measurement. Alternatively, the shear modulus distribution measured by using the response data evaluated analytically or numerically in this model is calibrated. Alternatively, it is possible to evaluate the shear modulus distribution using strain data evaluated analytically or numerically in this model and calibrate the measured shear modulus distribution using this. However, it is not necessary to strictly model the measurement target and the force source as the region of interest moves away from the force source. Absolute change of shear modulus distribution over time
The (difference value) is obtained by evaluating the difference between the absolute values μ (x, y, z), μ (x, y), μ (x) evaluated at the reference time and at different times. In addition, when evaluating the relative change (ratio value) of the shear modulus distribution over time, lnμ (x, y, z), ln
Evaluate the difference between μ (x, y) and lnμ (x). Alternatively, the absolute value or the relative value μ (x, y, z), μ (x, y), μ (x) is evaluated, and then the ratio value is evaluated. As described above, the signal processing relating to the shear elastic modulus estimation result can be performed in a state where natural logarithm is taken and a state where the natural logarithm is removed. In addition, in this case, in the calculation of the shear elastic modulus distributions lnμ (x, y, z), lnμ (x, y), and lnμ (x) by the formulas (8) to (10), the conjugate gradient method or the like is used. An iterative solution method may be adopted, but as the initial value of the estimated value at that time, by using the estimated value evaluated at the previous time,
The amount of calculation can be reduced.

Next, the procedure for measuring the shear elastic modulus distribution will be described in detail with reference to the flowchart of FIG. First, the reference region for the shear elastic modulus is set appropriately (S11).
At least one reference point is set in the region of interest 7 as a reference region for the shear modulus. Here, the point at which the reference point offset elastic modulus is known, or the point assumed to have a value of unit size. In order to improve the measurement accuracy of the shear elastic modulus, it is desirable to set the reference region within the region of interest so as to widely intersect the deformation direction. The reference region is a region having a known shear elastic modulus or a region which can be assumed to have a distribution having a shear elastic modulus a priori. In order to measure the absolute shear modulus distribution, a true value needs to be given as a reference value. If there is no reference point or reference region with a known shear modulus value in the region of interest, apply the reference object directly to the region of interest if possible, and then partly The strain tensor field is measured in the region of interest (S12). In this case, the shear elastic modulus value of the reference object is larger than that of the measurement target, and it is desirable to sandwich the reference object between the force source 8 and the region of interest. The object is
Strictly speaking, it deforms in a three-dimensional space, so it is desirable to perform a three-dimensional reconstruction. However, the one-dimensional reconstruction method (Equation 3), which positively uses strain data in the deep direction that can be measured with high accuracy, is useful for evaluating the shear modulus in the shallow portion of the object. On the other hand, when evaluating the shear modulus in the deep part of the object, the multidimensional reconstruction
(Equations 1, 2, 2 ') is useful and allows a high degree of freedom in setting the force source and the reference region. Especially 2
For dimensional reconstruction, if the strain in the z direction is close to zero due to the force applied to the surface of the region of interest from both sides in the z direction, use Equation 2; In this case, Equation 2'is used. When measuring an independent strain tensor field, the position of only the force source 8 is changed. This is because the measurement accuracy of the strain is determined by the size thereof, and therefore it is necessary to set and measure the force source 8 at various positions in order to realize the uniform measurement accuracy of the shear elastic modulus over the entire region of interest. is there. As a matter of course, since the measurement time and cost are required, the number of measurements has a trade-off relationship with the measurement accuracy. On the contrary, when the object is naturally deformed by the force sources 8 ′ and 8 ″, the force source 8 is not necessary and only the naturally occurring strain tensor field needs to be measured.

For the measurement of the shear elastic modulus, the measurement control means 3 adjusts the positions of the measurement object 6 and the detection sensor 5 and inputs the position information and the detection signal to the data recording means 2. In the data processing means 1, distortion measurement data is filtered for noise removal (S13) and spatially smoothed to obtain coefficients E and e (S14). Then
The matrix and vector of equation (10) are obtained to obtain the shear elastic modulus distribution s of the region of interest (S15). The measurement result of the data processing unit 1 is input to the data recording unit 2 in order to record the strain tensor component distribution, strain tensor component gradient distribution, shear elastic modulus distribution, and shear elastic modulus gradient distribution of the measurement result. Further, in order to display these measurement results on a display device such as a CRT (color / grey) in real time, the data processing means 1
Output can be input to a display device.

Further, in combination with the ultrasonic diagnostic apparatus, it is possible to simultaneously measure and image the spatial change in bulk modulus and density. As a result, a comprehensive evaluation is made on the organization related to the region of interest. In this case,
The data processing means 1, the data recording means 2, the measurement control means 3, the displacement or strain detection sensor 5, the drive / output adjusting means 5 ', etc. are used together. Further, in combination with the magnetic resonance imaging apparatus, the measurement and imaging of the atomic density distribution may be performed at the same time.

As the measurement results, in addition to the strain tensor component distribution, strain tensor component gradient distribution, shear elastic modulus distribution, and shear elastic modulus gradient distribution at each time, relative changes (ratio Value) or the absolute change (difference) is evaluated by the data processing means 1. Then, the evaluation results can be recorded in the data recording means 2 and can be output and displayed on the display device.

Further, these measurement results are subjected to spatial filter processing on a spatially absolute shear elastic modulus distribution or a spatially relative shear elastic modulus distribution, and then recorded and displayed on the data recording means 2. Output can be displayed on the device. Further, after temporal change processing (temporal filter processing) or temporal change processing of the relative change (ratio value) of the time-dependent change (difference value) of the shear elastic modulus distribution, the data is recorded in the data recording means 2 and the display device. The output can be displayed. The spatial filtering process, the temporal filtering process, or the spatiotemporal filtering process is for selecting or emphasizing a component when displaying or quantifying using a frequency as an index, and a high-frequency emphasis type, a middle-frequency emphasis type, and a low-frequency emphasis type. Mold,
A high-pass type, a mid-pass type, a low-pass type, etc. can be appropriately adopted. This filtering process is performed by the data processing means 1.

As described above, according to the embodiment of FIG. 1, the displacement or strain detection sensor 5 is used to remotely measure the strain tensor field in the region of interest, and the first-order floor described by the measured value is displayed. By solving the spatial partial differential equation using the finite difference method or the finite element method, the relative shear elastic modulus distribution with respect to the reference shear elastic modulus given in the region of interest can be estimated by calculation.

Further, by using a regularized algebraic equation in the calculation of the shear modulus, even if the error (noise) data included in the strain measurement data or the reference region is narrow and the position is bad, It is possible to estimate the shear elastic modulus distribution from only strain measurement data.

According to the above-described embodiment, the force sources 8, 8 ′ and 8 ″ are acquired using the displacement / strain detection sensor 5 under the condition that they are outside the region of interest. It is possible to estimate the shear modulus of the region of interest only from the strain tensor field measurement data obtained by processing the ultrasonic scattering signal in the region of interest. The elastic modulus can be calculated from the strain tensor field data measured in the region of interest.Especially when the object deforms naturally, the shear elastic modulus distribution of the region of interest / region can be easily maintained without disturbing the field. It is also useful when there is a region of interest in the deep part of the object where it is considered difficult to generate a large deformation that exceeds the measurement accuracy.

In particular, the shear elastic modulus measuring apparatus according to this embodiment is extremely useful for monitoring the therapeutic effect such as radiation irradiation because the denaturation of the substance and the temperature change caused by the irradiation of radiation accompany changes in the shear elastic modulus. is there.

In the embodiment of FIG. 1, an example of measuring the strain tensor in the region of interest by the displacement / strain detection sensor 5 using the ultrasonic probe has been described, but the present invention is not limited to this. The shear elastic modulus of the region of interest can be calculated only from the strain tensor field in the region of interest 7 evaluated by signal processing of the nuclear magnetic resonance signal.

(Second Embodiment) FIG. 3 is a block diagram showing the overall configuration of an embodiment in which the shear elastic modulus measurement technique of the present invention is applied to ultrasonic treatment. In the medical field, treatment of a lesion site is performed by irradiation with intense ultrasonic waves, laser irradiation, electromagnetic RF wave irradiation, or electromagnetic microwave irradiation.
In the case of these non-invasive treatments, the treatment causes denaturation of the lesion site, changes in the composition component weight fraction, and changes in temperature. For example, when the target is a living body, denaturation of tissue protein causes tissue coagulation. Such material modification and temperature change are accompanied by changes in the shear elastic modulus. Therefore, by measuring the shear modulus of the lesion site and observing the change, the therapeutic effect due to non-invasiveness can be monitored non-invasively. Based on the monitoring results, the treatment interval, irradiation power intensity, irradiation time, irradiation interval, irradiation position (focus), irradiation shape (apodization) are used as indicators for dynamic digital electronic control and machine control. can do.

The treatment apparatus shown in FIG. 3 is a treatment apparatus for irradiating and treating a lesion with strong ultrasonic waves, and comprises an ultrasonic diagnostic apparatus and a shear elastic modulus measuring apparatus. Figure 3
As shown in FIG.
And a therapeutic oscillator 13 and a probe support portion 14. The ultrasonic probe 12 is formed by arranging a plurality of transducers in a line like a convex type, like the one used in a known ultrasonic diagnostic apparatus.
It is attached to the probe support portion 14. The therapeutic transducer 13 is attached to the probe support 14 by dividing a plurality of transducers on both sides of the ultrasonic probe 12 and symmetrically arranging them. In the figure, the ultrasonic wave emitting surfaces of the plurality of oscillators of the therapeutic oscillator 13 are arranged so as to form a concave curved surface. The probe supporting portion 14 is designed to be gripped by hand or the position adjusting means 4 of FIG. Thereby, the position of the treatment probe 11 can be adjusted.

The ultrasonic wave pulse generated by the therapeutic pulse generating circuit 21 is supplied to the therapeutic oscillator 13 of the therapeutic probe 11 via the therapeutic wave delay circuit 22 and the amplifier 23. In other words, the treatment wave delay circuit 22 performs delay control for each transducer, converts it into a high-energy drive pulse by the amplifier 23, and supplies the drive pulse to each transducer. The focal position of the emitted ultrasonic beam is formed so as to be controllable at the treatment site.

On the other hand, in the ultrasonic probe 12, the ultrasonic pulse generated from the ultrasonic pulse generation circuit 31 is subjected to focus processing in the transmission delay circuit 32, amplified in the amplifier 33, and then the transmission / reception separator 34. It is adapted to be supplied to a transducer forming the ultrasonic probe 12 via the. The echo signal of the ultrasonic wave received from the living body by the ultrasonic probe 12 is transmitted to the amplifier 35 via the transmission / reception separator 34.
After being amplified and amplified, the phase of the echo signal is phased in the wave receiving and phase adjusting circuit 36. Image reconstruction is performed in the signal processing unit 37 based on the echo signal output from the wave receiving and phasing circuit 36.
It is converted into a diagnostic image by (digital scan converter) 38 and displayed on the monitor 39. A well-known ultrasonic diagnostic apparatus can be applied to the portion related to these diagnostic apparatuses.

The shear elastic modulus measuring section 40 according to the feature of this embodiment is adapted to calculate the shear elastic modulus by the above-mentioned procedure based on the echo signal output from the wave rectifying circuit 36. There is. The measurement data and the calculation result are stored in the data recording means provided in the shear elastic modulus measuring unit 40.

Further, the above-mentioned treatment pulse generation circuit 21, treatment wave delay circuit 22, ultrasonic pulse generation circuit 31, transmission delay circuit 32, reception wave phasing circuit 36, signal processing section 37, DS
The C38 and the shear elastic modulus measuring means 40 include a control unit 41.
Is controlled by the command of. Further, the operator can set various operation conditions and treatment conditions by inputting a command from the operation unit 42 to the control unit 41. The signal processing unit 37, the shear elastic modulus measuring unit 40, the operation unit 42, and the control unit 41 are configured by a computer.

An outline of the operation when ultrasonic treatment is performed using the ultrasonic treatment apparatus configured as described above will be described. First, the treatment probe 11 is brought into contact with the body surface of a living body and supported toward a region of interest in the living body including a desired treatment site. First, to image the treatment site prior to treatment,
When a command to start imaging is input from the operation unit 42, in response to this, the control unit 41 outputs a command to the ultrasonic pulse generation circuit 31 and the transmission delay circuit 32. As a result, an ultrasonic beam is emitted from the ultrasonic probe 12 into the living body to be measured. This ultrasonic beam is scanned along the array direction of the transducers of the ultrasonic probe 12, and the ultrasonic beam is applied to the region along the fan-shaped tomographic plane of the living body. The ultrasonic echo reflected from the area irradiated with ultrasonic waves is the ultrasonic probe 1
The echo signal received by the transducer 2 is subjected to phasing processing for each ultrasonic beam in the wave phasing circuit 36,
A two-dimensional image of the tomographic plane is generated by the image processing unit including the signal processing unit 37 and the DSC 38 and displayed on the monitor 39. In this way, the inside of the living body is diagnosed while observing the tomographic image, and the treatment is performed when the treatment site appears on the tomographic image while observing the tomographic image.

That is, when the treatment site appears on the image,
The position of the treatment probe 11 is held at the current position. Then, the control unit 41 obtains the delay time of the drive pulse supplied to each transducer of the therapeutic transducer 13 on the basis of the tomographic image stored in the DSC 38, and outputs the delay time to the therapeutic wave delay circuit 22. The beam focus position of the ultrasonic waves emitted from the therapeutic transducer is adjusted to the treatment site. Further, the irradiation intensity of the ultrasonic beam may be adjusted. As a result, the treatment site is heated and cauterized to degenerate the lesion site. This treatment operation is repeated at intervals as necessary. In addition, treatment may be performed while observing a three-dimensional ultrasonic image. The control of the ultrasonic beam for treatment is not limited to the control of the beam focus position (irradiation position),
The treatment interval, ultrasonic beam power, irradiation time, beam shape (apotization), and other controls are combined as appropriate.

Next, the procedure of shear elastic modulus measurement and treatment operation for monitoring the effect of treatment will be described with reference to the flowchart of FIG. First, the shear elastic modulus distribution μ (x, y, z) in the region of interest before the start of treatment is measured (S2
1). For this measurement, a command is sent from the operation unit 42 to the control unit 41, and the ultrasonic probe 12 is used as a force source to irradiate the region of interest in the living body with ultrasonic waves, thereby deforming the living body in the region of interest. Next, the control unit 41 controls the shear elastic modulus measuring unit 4
A command is sent to 0, the echo signal received from the ultrasonic probe 12 is taken in from the wave rectifying circuit 36, and the strain tensor field is measured by the procedure described above. The shear modulus distribution μ (x, y, z) is calculated based on the measured strain tensor field.

Next, the treatment site in the region of interest is confirmed, and the irradiation number counter I is initialized (I = 0) (S22).
Then, the treatment start position and the initial intensity of the treatment ultrasonic waves are set (S23), and the treatment is started (S24). With each treatment, the absolute shear modulus distribution μ (x,
y, z) is measured (S25). At this time, the elastic modulus to be measured may be not only absolute but also spatial and temporal relative. Then, it is confirmed whether or not a desired therapeutic effect is obtained by comparing with a preset threshold value TH1 (for softening) or TH2 (for hardening) for confirming a preset therapeutic effect. (S26). TH1 and TH
2 is a threshold value which is a function of the irradiation number I and the position (x, y, z), and has a unit of absolute or relative shear elastic modulus value. If the desired effect is not obtained, the ultrasonic intensity is adjusted to be high (S27), and the treatment is performed again (S24). When the desired therapeutic effect is obtained, it is determined whether or not the treatment has been completed for all the points set in the predetermined treatment site (S28). If the treatment has not been completed for all treatment points, the treatment position is changed (S2
9) Then, the treatment is executed again (S24).

If the treatment has been completed for all treatment points, the treatment site is cooled (S30). This cooling may be natural cooling or forced cooling. After that, that is, the shear elastic modulus distribution μ (x, y, z) in the region of interest after treatment is measured (S31). Then, it is determined whether or not desired treatment effects have been obtained for all the points set in the predetermined treatment site (S32). If the therapeutic effect is not obtained,
Further cooling is performed until the therapeutic effect is obtained, and the shear elastic modulus distribution μ (x, y, z) is measured (S30 to S32).
When the desired treatment effect is obtained for all the points set in the predetermined treatment site, it is determined whether or not the treatment is terminated (S33). When the treatment is not finished, the irradiation number counter I is incremented, and S23 to S33 are repeated until the treatment is finished for a predetermined number of times of irradiation. When the treatment of all the lesion parts is finished, the process is finished. In addition, basically, the irradiation position may not be sequentially set from the deep part in the region of interest, but the irradiation position of the treatment may be changed after confirming the therapeutic effect of the irradiation position value.

As described above, according to the treatment apparatus of the embodiment shown in FIG. 3, the treatment effect can be observed in real time while performing the treatment by ultrasonic waves, and the proper treatment can be performed. In addition, the ultrasonic intensity and the number of times of irradiation can be adjusted while confirming the therapeutic effect.

Although the treatment apparatus of FIG. 3 has been described by way of example of treatment by ultrasonic irradiation, the present invention is not limited to this, and treatment by laser irradiation, electromagnetic RF wave irradiation, or electromagnetic microwave irradiation. Can also be applied to. In this case, the treatment oscillator 11, the treatment pulse generation circuit 21, the treatment wave delay circuit 22, and the amplifier 23 may be replaced with a non-invasive treatment means such as a laser irradiation means. In addition, the ultrasonic probe 12
For example, a two-dimensional array type opening, a one-dimensional array type opening, or a concave opening applicator can be used. And, for example, in the case of targeting a living organism or a collected tissue, transdermal, oral, vaginal, transanal, trans-object surface such as open body, strong ultrasonic irradiation, laser irradiation, electromagnetic RF wave irradiation,
It is possible to monitor the material modification, the change of the composition component weight fraction, and the temperature change when the electromagnetic microwave is irradiated. At that time, the measured shear elastic modulus value, the treatment implementation interval,
It can be used as an index for dynamically controlling the irradiation power intensity, irradiation time, irradiation interval, irradiation position (focus), and irradiation shape (apodization). In particular, if the applicator has arrayed apertures, these are digitally electronically controlled, and if the applicator has a concave aperture, the illumination geometry is often fixed. In that case,
The irradiation position is mechanically controlled. It goes without saying that a high irradiation spatial resolution is required, and as the control program in that case, for example, the flowchart shown in FIG. 3 can be applied. That is, the absolute shear elastic modulus distribution or the relative shear elastic modulus distribution itself measured before irradiation, during irradiation, or after irradiation, or its change over time, the irradiation power intensity, irradiation interval, irradiation (focus) position Can be used as an index for dynamically controlling.

In addition, using an invasive device such as a puncture needle or a catheter, powerful ultrasonic irradiation, laser irradiation, electromagnetic RF
It can also be applied in the case of treatments with wave irradiation or electromagnetic microwave irradiation.

Further, even if there is no force source or if the force source is not actively used, the substance modification and composition can be determined from the strain (tensor) distribution and shear elastic modulus distribution measured before irradiation, during irradiation, and after irradiation. The position where the component weight fraction has changed and the temperature has changed can be detected. Further, at the time of measuring the strain tensor component distribution, it is possible to directly detect expansion, degeneration, and the like due to this change. In addition, when performing the above treatment, in order to ensure safety, conventional temperature monitoring,
Alternatively, the temperature change distribution may be simultaneously measured using a thermocouple or the like in pursuit of measurement accuracy. Basically,
It is preferable to set an upper limit value for the temperature and control the irradiation power intensity, irradiation time, irradiation interval, irradiation position, and irradiation shape so that the temperature does not rise more than necessary. In that case, it is also possible to control after converting the upper limit value of the temperature into the shear elastic modulus value μ and the strain value e.

Further, the shear modulus measuring apparatus of the present invention is applied to the case where a substance is denatured or a composition component weight fraction is changed, which may be accompanied by a temperature change due to injection, application or administration of a drug, or an organism or a sampled tissue. Can be used to monitor therapeutic effects. In this case, before, during, and after
An index for determining the absolute shear elastic modulus distribution or relative shear elastic modulus distribution to be measured, and the absolute change over time or relative change over time of the amount of the drug, execution time, execution interval, and execution position. Can be used as Examples of such drugs are anti-cancer agents.

[0076]

As described above, according to the present invention, even when another force source exists in the object to be measured or there is a force source that cannot be controlled, It is possible to provide a shear elastic modulus measuring device that can be applied to diagnosis of a region of interest and monitoring of therapeutic effects.

Further, according to the present invention, it is possible to provide a non-invasive treatment device equipped with a shear elastic modulus measuring device.

[Brief description of drawings]

FIG. 1 is an overall block configuration diagram of a shear modulus measuring apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart of an embodiment of a shear elastic modulus measurement procedure.

FIG. 3 is an overall block configuration diagram of an ultrasonic therapeutic apparatus including the shear elastic modulus measuring device of the present invention.

FIG. 4 is a flowchart showing a control procedure of the ultrasonic therapy apparatus of FIG.

[Explanation of symbols]

1 Data processing means 2 Data recording means 3 Measurement control means 4, 4 ', 4 "position adjusting means 5 Displacement / strain detection sensor 5 ', 5 "drive / output adjusting means 6 object to be measured Area of interest 8,8 ', 8 "power source 9 liquid tank

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01N 29/00 A61B 17/36 330 F term (reference) 2G047 AA05 AC13 AD08 BA03 BC14 BC20 CA01 DB02 EA08 EA10 GA03 GB02 GB17 GE03 GF17 GG19 GG34 4C060 EE19 JJ25 JJ27 MM24 4C301 AA02 BB23 DD11 DD30 EE19 EE20 FF26 GA11 GB03 GB09 GC12 HH02 HH24 HH25 HH37 HH38 HH45 JB29 JB35 GB05 GB16 FF16 BB16 BB16 BB16 BB16 BB30 BB30 BB30 BB30 BB30 HH30 HH31 HH35 JB01 JB28 JB34 JB45 JB55 JB60 JC37 KK31 LL01 LL02 LL40

Claims (7)

[Claims] 1. A storage unit for storing strain tensor data measured for a region of interest set in a measurement object, and a shear elastic modulus of an arbitrary point in the region of interest is calculated based on the strain tensor data. Shear elastic modulus computing means, wherein the shear elastic modulus computing means obtains the shear elastic modulus by numerical analysis based on a first-order partial differential equation expressing the relationship between the strain tensor and the shear elastic modulus. Characteristic device for shear modulus measurement. 2. Storage means for storing strain tensor data measured for a region of interest set in a region including a lesion part of a living body, and displacement of an arbitrary point in the region of interest based on the strain tensor data. A shear elastic modulus calculating means for calculating an elastic modulus; and an output means for outputting degeneration information of a site including the lesion based on the calculated shear elastic modulus, the shear elastic modulus calculating means comprises: A shear elastic modulus measuring device, characterized in that the shear elastic modulus is obtained by numerical analysis based on a first-order partial differential equation representing a relationship between a tensor and the shear elastic modulus. 3. The shear modulus of elasticity according to claim 2, wherein the output means compares the calculated shear modulus of elasticity with a set value and outputs the modification information corresponding to the comparison result. Measuring device. 4. The shear modulus computing means uses a Poisson ratio of a pre-measured value or a preset value when the Poisson's ratio of the object in the region of interest is related to the first-order partial differential equation. The shear elastic modulus measuring device according to any one of claims 1 to 3, characterized in that. 5. The shear shear modulus computing means uses a reference shear modulus which is measured or set in advance as an initial condition when solving the first-order partial differential equation. The shear elastic modulus measuring device described in Crab. 6. The shear elastic modulus computing means uses a finite difference method or a finite element method as a numerical analysis method for solving the first-order partial differential equation, and also uses a regularized algebraic equation. Item 10. The shear elastic modulus measuring device according to any one of items 1 to 5. 7. A therapeutic oscillator in which a plurality of oscillators are arrayed, a therapeutic wave transmission circuit for outputting an ultrasonic wave drive signal to each oscillator of the therapeutic oscillator, and a plurality of oscillators are arrayed. The ultrasonic probe, a wave transmission circuit that outputs an ultrasonic drive signal to the ultrasonic probe, and a receiver that receives the echo signal output from the ultrasonic probe and performs phasing processing. Wave circuit,
Shear elastic modulus calculating means for calculating a shear elastic modulus based on the echo signal phased by the wave receiving circuit, and an output for outputting degeneration information of a site including the lesion based on the calculated shear elastic modulus Means, a therapeutic wave transmitting circuit, the wave transmitting circuit, the wave receiving circuit, and a shear elastic modulus calculation means, and a control section for inputting an operation command to the control section. Is a function of controlling the transmitting circuit and the receiving circuit based on an operation command input from the operation unit to deform the region of interest set in the living body of the subject, and the therapeutic transmitting circuit. And a function of controlling an ultrasonic beam emitted from the therapeutic oscillator by controlling the shear elastic modulus calculation means based on a command given from the control unit to transform the region of interest. By capturing such an echo signal, It calculates the distortion tensor data of frequency treatment apparatus characterized by calculating the shear modulus of the region of interest on the basis of the distortion tensor data.