WO2018193731A1

WO2018193731A1 - Body tissue position measurement device, radiation therapy device, and body tissue position measurement method

Info

Publication number: WO2018193731A1
Application number: PCT/JP2018/008404
Authority: WO
Inventors: 雅則北岡; 友輔高麗
Original assignee: 株式会社日立製作所
Priority date: 2017-04-20
Filing date: 2018-03-05
Publication date: 2018-10-25
Also published as: JP6867218B2; JP2018175688A

Abstract

This body tissue position measurement device is provided with: an ultrasound propagation model generation unit 103 for generating an ultrasound propagation model using 3D-information synchronized with the respiration of a patient 100; an ultrasonic image simulation unit 105 for calculating a simulated ultrasonic image by simulating the propagation of ultrasound in the ultrasound propagation model; a database 106 for storing the simulated ultrasonic image in linkage with the patient 3D-information; and a body tissue position calculation unit 111 for calculating the position of a tissue in the body of the patient 100 by comparing, on the basis of a respiratory state measured by a respiratory state measurement unit 110, a real ultrasonic image formed by an ultrasonic image formation unit 109 and the simulated ultrasonic image stored in the database 106.

Description

Body tissue position measuring apparatus, radiation therapy apparatus, and body tissue position measuring method

The present invention relates to an in-vivo tissue position measuring apparatus, a radiotherapy apparatus, and an in-vivo tissue position measuring method for measuring a specific tissue position in a patient body with ultrasound.

Patent Documents 1 and 2 describe a method for measuring the position of a body tissue.

Patent Document 1 discloses high-precision radiation irradiation by detecting the behavior of a treatment target site caused by patient's breathing, pulsation or body movement without particularly increasing the size and excessive complexity of the device itself. For the purpose of providing a non-invasive and highly safe radiotherapy apparatus that can perform treatment, an ultrasonic image for treatment planning is simultaneously imaged at the time of imaging a CТ image for treatment planning, The ultrasonic image for treatment imaged in real time and the ultrasonic image for treatment plan are compared to determine whether or not the correlation value of both ultrasonic images is equal to or greater than a predetermined value. It is described that the radiation irradiating means is controlled so that the radiation to the treatment target site is performed only at the time of the above.

In Patent Document 2, for the purpose of providing an ultrasonic medical system that outputs appropriate information related to a tissue position, an ultrasonic diagnostic apparatus outputs echo data to a host controller, and a tissue coordinate calculation unit includes a three-dimensional probe. The coordinate information of the tumor with the child as the origin is calculated, the probe coordinate calculation unit calculates the coordinate information of the three-dimensional probe with the X-ray irradiation device as the reference point as the origin, and the total tissue coordinate calculation unit is Based on the coordinate information of the tumor whose origin is the 3D probe and the coordinate information of the 3D probe whose origin is the X-ray irradiation device, the coordinate information of the tumor whose origin is the X-ray irradiation device is calculated. And output to an X-ray irradiation apparatus.

JP 2003-1117010 A JP 2004-049999 A

There are three main cancer treatment methods: surgery, chemotherapy, and radiation therapy.

Among these, radiation therapy is a treatment method that kills cancer cells by irradiating a body tissue that is a treatment target site of a patient with a high dose of radiation, and can concentrate radiation on the treatment site. This is a method with relatively light side effects.

In order to carry out radiation therapy efficiently, it is important that the area where the radiation is concentrated and the area where the cancer tumor to be treated is present coincide with each other with high accuracy.

In a conventional radiotherapy apparatus, the position of a body tissue that is a treatment target site is specified from information such as a CT (Computed Tomography) image acquired in advance, and a treatment plan is made based on the position. Thereafter, the patient is fixed to the treatment table of the radiotherapy apparatus, and the radiation is irradiated to the body tissue that is the treatment target site of the patient by controlling the radiation characteristics such as the irradiation direction and intensity.

However, due to the patient's own breathing during the radiation irradiation, the patient's treatment target region moves from the radiation irradiation position planned in advance, which has been a problem for accurate treatment.

In response to this problem, a marker made of gold or the like is embedded in the patient's body in advance, and the movement of the treatment target region is detected by capturing and tracking this marker with an X-ray transmission image, and a prior treatment plan A method of treating with high accuracy has been established by using it for radiation control during irradiation.

On the other hand, the realization of a less invasive body tissue position measuring device that can suppress the exposure dose due to X-ray irradiation during treatment and that can respond to patient movement such as breathing is aimed at further reducing the exposure dose. It is desired. As one of the less invasive methods, there is a method using an ultrasonic image.

In Patent Literature 1, instead of markers and X-rays, radiation that emits radiation at a timing when the correlation value between an ultrasound image acquired in advance with a CT image acquired in advance and an ultrasound image acquired during treatment is high. A treatment device is described.

The radiotherapy apparatus described in Patent Document 1 irradiates radiation using a treatment planning ultrasonic image acquired in the same phase as a CT image acquired in advance and a therapeutic ultrasonic image acquired during treatment. By controlling it, treatment is possible with minimal invasiveness. However, radiation is applied at the timing when an ultrasound image for treatment planning having a high correlation value with the treatment ultrasound image is obtained, and the position of the body tissue under treatment is not specified from the ultrasound image. Therefore, there is a problem that an error in position with the actual treatment target region may occur.

The ultrasonic medical system described in Patent Document 2 specifies the coordinates of a tumor in a patient body using a three-dimensional ultrasonic image obtained by using a three-dimensional ultrasonic probe, and provides coordinate information to the X-ray irradiation apparatus. I am trying to output. However, there is a problem that the recording of ultrasonic waveforms and data processing take time, and the system becomes complicated.

Further, paragraph (0024) of Patent Document 2 states that a two-dimensional ultrasonic probe may be used to transmit and receive waves only within the two-dimensional scanning plane instead of the three-dimensional ultrasonic probe. There is a description. However, since the target tissue including the tumor moves not only in the cross section of the ultrasonic image but also in a direction away from the cross section, it is not necessary to use a two-dimensional ultrasonic probe instead of a three-dimensional ultrasonic probe. There is a problem that an error may occur between the tumor position and the measurement position.

The present invention has been made in view of the above problems, and is capable of measuring a body tissue position accurately and in real time using a less invasive ultrasonic wave without complicating the system. It is an object of the present invention to provide a measurement apparatus, a radiotherapy apparatus, and a body tissue position measurement method.

The present invention includes a plurality of means for solving the above-described problems. For example, the present invention is a body tissue position measuring apparatus for measuring the position of a tissue in a patient body by ultrasonic waves, and is a patient synchronized with breathing. A 3D information acquisition unit for acquiring 3D information, a patient 3D information storage unit for storing the 3D information acquired by the respiratory synchronization 3D information acquisition unit, and the patient 3D stored in the patient 3D information storage unit An ultrasonic wave propagation model creating unit that creates an ultrasonic wave propagation model using information, and a pseudo ultrasonic image by simulating ultrasonic propagation in the ultrasonic wave propagation model created in the ultrasonic wave propagation model creating unit An ultrasonic image simulation unit for calculating the image and the pseudo ultrasonic image calculated by the ultrasonic image simulation unit in association with the patient 3D information. A database, an ultrasonic transmission / reception unit that transmits ultrasonic waves toward the patient's body, and receives ultrasonic waves returning from the patient's body, and an actual ultrasonic image from the ultrasonic waves received by the ultrasonic transmission / reception unit Based on the respiratory state measured by the respiratory state measuring unit, the respiratory state measuring unit configured to measure the respiratory state of the patient, and the real image configured by the ultrasonic image configuring unit A body tissue position calculating unit that compares a sound image and a pseudo ultrasound image stored in the database to calculate a tissue position in the patient's body.

According to the present invention, it is possible to accurately and in real time measure the position of a body tissue within a patient's body without complicating the system by using a less invasive ultrasonic wave.

It is a figure which shows the structure concept of the body tissue position measuring apparatus of 1st Example of this invention. It is a schematic diagram which shows the mode of the change of the body tissue position in a patient body. It is a schematic diagram which shows the change of the ultrasonic cross section image by the change of the body tissue position in a patient body. It is a schematic diagram which shows the change of the ultrasonic cross section image by the change of the body tissue position in a patient body. It is a conceptual diagram which shows the ultrasonic wave propagation model produced | generated by the body tissue position measuring apparatus of 1st Example of this invention. It is a conceptual diagram which shows the body tissue position measuring method by the comparison of a real ultrasonic image and tumor 3D information. It is a conceptual diagram which shows the body tissue position measuring method by the comparison of a real ultrasonic image and tumor 3D information. It is a flowchart which shows the database construction method by the body tissue position measuring apparatus of 1st Example of this invention. It is a flowchart which shows the body tissue position measuring method by the body tissue position measuring apparatus of 1st Example of this invention. It is a flowchart which shows the comparison method of the real ultrasonic image and pseudo | simulation ultrasonic image by the body tissue position measuring apparatus of 1st Example of this invention. It is a figure which shows the concept of the example of application to the radiation irradiation apparatus of the body tissue position measuring apparatus of 2nd Example of this invention. It is a conceptual diagram of the ultrasonic cross-sectional image in the body tissue position measuring apparatus of the 3rd Example of this invention.

Embodiments of a body tissue position measuring device, a radiotherapy device, and a body tissue position measuring method according to the present invention will be described below with reference to the drawings.

<First embodiment>
A first embodiment of the body tissue position measuring apparatus and body tissue position measuring method of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected about the part which is common in FIG. 1 thru | or FIG.

FIG. 1 is a conceptual diagram of a configuration of a body tissue position measuring apparatus according to the present embodiment, FIG. 2 is a schematic diagram showing a change in body tissue position in a patient body, and FIGS. 3A and 3B are changes in body tissue position in the patient body. FIG. 4 is a conceptual diagram showing an ultrasonic propagation model generated by the present embodiment, and FIGS. 5A and 5B are internal tissues based on comparison between real ultrasonic images and patient 3D information. FIG. 6 is a flowchart showing a database construction method according to the present embodiment, FIG. 7 is a flowchart showing a body tissue position measuring method according to the present embodiment, and FIG. 8 is an actual ultrasonic image according to the present embodiment. It is a flowchart which shows the comparison method with a pseudo-ultrasonic image.

First, the configuration and role of the in-vivo tissue position measuring apparatus according to the present embodiment will be described with reference to FIGS. 1 to 5B.

In FIG. 1, the body tissue position measuring device is a device that measures the three-dimensional body tissue position of a patient 100 fixed to a bed 500 by using ultrasonic waves, and mainly includes a respiratory synchronization 3D information acquisition unit 101, Patient 3D information storage unit 102, ultrasound propagation model creation unit 103, body tissue position change unit (input device) 104, ultrasound image simulation unit 105, database 106, ultrasound probe 107, ultrasound transmission / reception unit 108, ultrasound The sonic image forming unit 109, the respiratory state measuring unit 110, the body tissue position calculating unit 111, and the body tissue position output unit 112 are configured.

In the body tissue position measuring apparatus, the patient 100 is fixed to the bed 500 in a state where the ultrasonic probe 107 whose position is fixed by a fixing jig 107a such as a robot arm is pressed against the body surface. Is done.

The ultrasonic probe 107 receives an electrical signal from the ultrasonic transmission / reception unit 108, excites the ultrasonic wave, and transmits it to the body of the patient 100. In addition, ultrasonic waves that are returned from the body of the patient 100 due to reflection, scattering, and the like are received, converted into electrical signals, and transmitted to the ultrasonic transmission / reception unit 108. The ultrasonic transmission / reception unit 108 amplifies the electrical signal received from the ultrasonic probe 107 and sends it to the ultrasonic image construction unit 109.

In general, ultrasonic elements 107 are arranged in a line inside the ultrasonic probe 107, and by controlling the excitation timing by the ultrasonic transmission / reception unit 108, the ultrasonic focus position and the like can be scanned. It has become.

The ultrasonic image construction unit 109 acquires an ultrasonic image in the ultrasonic scanning range by synthesizing the ultrasonic reception signals received by the ultrasonic transmission / reception unit 108 such as reflection and scattering.

Here, FIG. 2 is a schematic diagram showing a change in the position of the body tissue in the patient. When the center of the tumor 201 to be measured exists in the ultrasonic scanning section 202, the body tissue position can be easily calculated from the acquired ultrasonic image. However, when the position of the tumor 201 changes with the breathing of the patient 100 as shown in FIG. 2, the ultrasonic scanning section 202 and the center of the tumor 201 do not necessarily coincide with each other and often do not coincide with each other.

FIG. 3A and FIG. 3B schematically show changes in the ultrasonic cross-sectional image due to changes in the patient's body tissue position.

When the ultrasonic scanning section 202 and the center of the tumor 201 coincide, an image of the organ 302A and the tumor 303A is drawn in the actual ultrasonic image 301A as shown in FIG. 3A.

On the other hand, when the ultrasonic scanning section 202 and the center of the tumor 201 do not coincide with each other, images of the organ 302B and the tumor 303B are drawn in the actual ultrasonic image 301B as shown in FIG. 3B.

Here, the image of the tumor 303A shown in FIG. 3A and the image of the tumor 303B shown in FIG. 3B depict the tumor 201 that is the same body tissue, but the relative images of the actual ultrasound images in the

organs

302A and 302B. It is drawn at different positions and sizes. Only from the actual ultrasound image 301A and the actual ultrasound image 301B, it is possible to estimate the body tissue position in the two-dimensional image, and it is difficult to calculate the three-dimensional body tissue position. Or the accuracy may not be enough.

Therefore, in the present invention, 3D information of the patient 100 synchronized with respiration is acquired and stored in advance, and ultrasonic images corresponding to various target body tissue positions are created by simulation using the 3D information described above. . Furthermore, the ultrasonic image obtained by this simulation and the target in-vivo tissue position in the 3D information described above are associated with each other and stored in the database. Then, when imaging the patient's body using ultrasound and calculating the body tissue position, referring to the database described above, the ultrasound image obtained by the measurement and the ultrasound image obtained by the simulation are obtained. By comparing, the corresponding body tissue position is found. Hereinafter, a configuration and operation for creating an ultrasonic image by simulation will be described.

In FIG. 1, the respiratory synchronization 3D information acquisition unit 101 captures a CT image including at least a body tissue that is a position calculation target at a timing synchronized with respiration, for example. By capturing CT images at a plurality of timings for each respiratory phase, information on the body tissue position of the patient 100 and other tissues for each respiratory phase is acquired as 3D information. At this time, the ultrasound probe 107 may create an artifact of the CT image. In such a case, when acquiring 3D information, instead of the ultrasonic probe 107, a dummy probe with few artifacts for simulating the pressing of the body surface by the ultrasonic probe 107 is fixed. It is desirable that the CT image is acquired by holding the tool 107a.

The information acquired by the respiratory synchronization 3D information acquisition unit 101 is sent to the patient 3D information storage unit 102 and stored in the patient 3D information storage unit 102.

As shown in FIG. 4, the ultrasonic propagation model creation unit 103 includes an ultrasonic wave in the patient body that is divided into appropriate small regions (mesh) according to the 3D information of the patient 100 stored in the patient 3D information storage unit 102. A sound wave propagation model 401 is created.

For example, in the ultrasonic propagation model creation unit 103, physical quantities necessary for calculating ultrasonic propagation such as the density and sound velocity value or acoustic impedance of each small region by the operator using the body tissue position changing unit 104 described later. The ultrasonic wave propagation model 401 is generated in response to the input of the combination setting. The operator discriminates fat, muscle, blood vessel, bone, organ, etc. from the patient 3D information, and sets a physical quantity in each small region according to the type of tissue. For example, it is known that the speed of sound in fat is about 1450 m / s, the speed of sound in blood, muscle, and organs is about 1530-1630 m / s, and the speed of sound in bone is about 2700-4100 m / s. Set an appropriate value according to the state. Also, fat, muscle, blood vessels, bones, organs, etc. are automatically discriminated by the ultrasonic wave propagation model creation unit 103 according to the brightness of the CT image, and the physical quantity is set in each reduced area according to the type of tissue. Can be automated.

Further, the ultrasonic propagation model creation unit 103 determines which cross-sectional ultrasonic image is to be obtained in the 3D model based on information on the position where the ultrasonic probe 107 is actually installed and the transmission direction of the ultrasonic wave. decide.

The body tissue position changing unit 104, for the ultrasound propagation model created by the ultrasound propagation model creating unit 103, is a body tissue to be measured or other fat, muscle, blood vessel, bone, organ, etc. This is a device for an operator or the like to arbitrarily change the direction of the position. For example, in an ultrasonic wave propagation model displayed on a computer screen, an operation means such as a mouse or input means such as text data can be used.

The ultrasonic image simulation unit 105 uses the means such as ultrasonic propagation analysis, and the ultrasonic wave propagation model created by the ultrasonic wave propagation model creation unit 103 or changed / corrected by the body tissue position changing unit 104 Analyzes the propagation path of ultrasonic waves entering the patient from the specified ultrasonic probe position, simulates reflection and scattering of ultrasonic waves in the patient, and produces pseudo-ultrasonic images (pseudo-ultrasound Image). For propagation analysis, a finite element method, a difference method, or a ray tracing method is generally known, and any method can be used as long as a certain accuracy is guaranteed, and the present invention is limited. It is not a thing.

The database 106 stores the pseudo-ultrasound image obtained by the ultrasound image simulation unit 105 in the body tissue position specified by the body tissue position changing unit 104 and the patient respiratory phase when acquired by the respiratory synchronization 3D information acquisition unit 101. Save it in a state associated with the information.

The respiratory state measurement unit 110 is a device or device that measures the respiratory state of the patient 100. Examples of the respiratory state measurement unit 110 include devices and devices that identify the respiratory phase by monitoring the movement of the body surface of the patient 100 using a laser distance meter, measuring the expiration of the patient, and the like. Various other methods can be employed as the respiratory state measurement unit 110, and therefore the example shown here does not limit the present invention.

The internal tissue position calculation unit 111 refers to the database 106, the ultrasonic image configuration unit 109, and the respiratory state measurement unit 110, and based on the respiratory state measured by the respiratory state measurement unit 110, the ultrasonic image configuration unit 109 performs real-time processing. The actual ultrasonic image acquired in step S3 is compared with the pseudo ultrasonic image obtained by the simulation stored in the database 106, and the tissue position in the body of the patient 100 is calculated. Hereinafter, an example of the comparison method will be described with reference to FIGS. 5A and 5.

In the in-vivo tissue position measuring apparatus of the present embodiment, as described above, the database 106 stores the patient 3D information 501 in a certain respiratory phase and the pseudo

ultrasonic images

501A, 501B,. A pseudo ultrasonic image that can be compared with a real ultrasonic image obtained during the sound wave measurement is obtained by simulation in a specific cross section of the patient 3D information.

Therefore, when the ultrasound scanning section matches the center of the body tissue, as shown in FIG. 5A, the pseudo ultrasound stored in the database 106 when the ultrasound scanning section matches the center of the body tissue. When the image 502A is called from the database 106, the organ 502A and the tumor 503A depicted in the pseudo-ultrasonic image 501A are compared with the organ 302A and the tumor 303A depicted in the real ultrasound image 301A, and it is determined that they match. Calculates the tissue position in the body of the patient 100 using the information of the actual ultrasonic image 301A.

On the other hand, when the ultrasound scanning cross section and the center of the body tissue do not coincide with each other, as shown in FIG. 5B, the information is stored in the database 106 based on the information of the respiratory phase at that time measured by the respiratory state measurement unit 110. In addition, the pseudo ultrasonic image 501B in the case where the ultrasonic scanning cross section and the center of the body tissue do not coincide with each other is called from the database 106, and the organ 502B and the tumor 503B depicted in the pseudo ultrasonic image 501B are converted into the real ultrasonic image 301B. When it is determined that they match with the organ 302B and the tumor 303B depicted therein, the tissue position in the body of the patient 100 is calculated using the information of the actual ultrasonic image 301B.

Here, when comparing the pseudo-ultrasonic image and the real ultrasonic image in the body tissue position calculation unit 111, for example, by the image processing or the like, the shape, size, and size of the body tissue in the cross-sectional image of the body tissue to be measured, A plurality of parameters such as position can be extracted and the difference can be compared quantitatively. For example, the difference between the two is calculated as an error, and the calculated error is compared with a predetermined threshold value. When the difference is smaller than the threshold value, it is determined that they match, and when the error is greater than or equal to the threshold value, it is determined that they do not match. it can. If it is determined that the two do not match, another body tissue position previously stored in the database 106 is designated, and an ultrasonic cross-sectional image obtained by simulation is referred to, and comparison is performed again. Search for matching data.

Further, in the comparison in the in-vivo tissue position calculation unit 111, for example, a correlation coefficient between images is calculated, and when a predetermined threshold value exceeds the correlation coefficient, it is determined that both match, and the correlation coefficient is the threshold value. It can be determined that they do not match in the following cases.

Here, when comparing the simulation and the actual ultrasonic cross-sectional image in the body tissue position calculation unit 111, it is assumed that the pixel size and the pixel shape obtained in the pseudo ultrasonic image and the real ultrasonic cross-sectional image are different. For example, if the pixel size greatly differs in shape, size, position, etc. in the cross-sectional image of the body tissue, it may be difficult to compare or it may be difficult to sufficiently ensure the accuracy of the comparison. Further, in order to calculate the correlation coefficient, it is necessary that the pixel size and the pixel shape of the two coincide at a certain level.

Therefore, the body tissue position calculation unit 111 first compares the resolution of the pseudo ultrasonic image and the real ultrasonic image, and interpolates the pixel data with respect to either the pseudo ultrasonic image or the real ultrasonic image. Therefore, it is preferable that the resolutions of both images are matched. As a pixel interpolation method, nearest neighbor interpolation, bilinear interpolation, bicubic interpolation, and the like are generally known, and an appropriate method can be selected according to target position calculation accuracy. The image to be interpolated may be either image, but it is desirable to match the lower resolution image with the higher resolution image.

When the matching data is found, the body tissue position calculation unit 111 outputs the corresponding body tissue position information to the body tissue position output unit 112. The output method may be, for example, displaying a relative position from a reference coordinate numerically on a monitor, displaying patient 3D information corresponding to the found ultrasonic cross-sectional image simulation result on the monitor, or appropriately encoded electrical There is a method of transmitting the signal by wire or wireless. In addition, as the output method, various methods can be adopted according to the purpose of use of the calculated in-vivo tissue position. Therefore, the example shown here does not limit the present invention.

The ultrasonic propagation model creation unit 103, the ultrasonic image simulation unit 105, the ultrasonic transmission / reception unit 108, the ultrasonic image configuration unit 109, and the body tissue position calculation unit 111 are each a computer, an FPGA (Field-Programmable Gate Array), or the like. This can be realized by loading the program and executing the calculation.

The patient 3D information storage unit 102 and the database 106 can be configured using various storage media such as a volatile memory, a nonvolatile memory, a hard disk, and an external storage device.

Next, with reference to FIGS. 6 to 8, the body tissue position measuring method according to the present embodiment using the above-described body tissue position measuring apparatus suitably will be described.

First, an ultrasonic propagation model creation method among the body tissue position measurement methods of the present embodiment will be described with reference to FIG.

In FIG. 6, first, processing is started (step S101). In this step, it is assumed that the patient 100 is already fixed to the bed 500. In addition, the ultrasonic probe 107 by the fixing jig 107a or a dummy probe with reduced artifacts is pressed against the patient 100 to simulate the actual ultrasonic image acquisition, and the patient 100 by the respiratory synchronization 3D information acquisition unit 101 or the like. It is assumed that preparations for measuring the respiratory status of the child have been completed.

Next, the respiratory synchronization 3D information acquisition unit 101 collects and stores 3D information for each respiratory phase of the patient 100 (step S102). In the following, the flow will be described using a case where a CT image is used as 3D information as an example.

Next, an ultrasonic propagation model is created by the ultrasonic propagation model creation unit 103 (step S103).

Next, in the ultrasonic wave propagation model created in step S103, the position and orientation of the ultrasonic probe 107 that is the starting point of the ultrasonic wave and the body tissue position to be measured are specified (step S104).

Next, ultrasonic propagation analysis is performed on the ultrasonic propagation model created in step S103 in a region including the position and orientation of the ultrasonic probe 107 specified in step S104 and the body tissue position, and a simulation image (pseudo image) is obtained. An ultrasonic image is created (step S105).

Next, the pseudo ultrasonic image created in step S105 is stored in the database 106 in combination with the body tissue position designated in step S104 (step S106).

Next, it is determined whether or not a sufficient amount of pseudo ultrasonic images has been stored in the database 106 (step S107).

In the body tissue position measurement method of the present embodiment, the number of pseudo ultrasound images stored in the database 106 affects the final body tissue position calculation accuracy. Specifically, the calculation accuracy of the body tissue position is an error of about the difference between the pseudo ultrasound images of the body tissue position specified in step S104. Therefore, in the determination in step S107, it is determined whether or not a sufficient amount of pseudo-ultrasonic images has been stored in the database 106 by determining whether or not the calculated final body tissue position calculation accuracy is sufficient for the purpose. Can be determined.

When it is determined that the storage amount of the pseudo-ultrasonic image stored in the database 106 is insufficient, the process returns to step S104, and simulation and pseudo-ultrasonic image creation processing are performed with another pattern. When it is determined that the pseudo ultrasonic image is sufficiently stored, the process proceeds to step S108.

It should be noted that the accuracy between the pseudo ultrasound images can be ensured by creating a pseudo ultrasound image by means other than the ultrasound propagation analysis by interpolation or the like.

Next, it is determined whether or not the patient 3D information is obtained with a necessary respiratory phase pattern (step S108). Similar to the description in step S107 described above, the number of necessary respiratory phase patterns to be used as a determination criterion is determined according to the final body tissue position calculation accuracy. When it is determined that the number of simulation patterns stored in the database 106 is insufficient, the process returns to step S102, and a simulation is performed using another patient 3D information. If it is determined that the number of patterns is sufficient, the process proceeds to step S109, and the ultrasonic wave propagation model creation process ends.

In this embodiment, an example of collecting a plurality of breathing states and body tissue position patterns has been shown. However, if sufficient accuracy can be ensured, only the measurement result of the patient's breath holding state may be used. Further, the human body may be simply modeled as a substance having a uniform density and sound velocity.

Next, with reference to FIGS. 7 and 8, a method for calculating the body tissue position in the body tissue position calculation unit 111 among the body tissue position measurement methods preferably using the above-described body tissue position measurement apparatus will be described.

First, processing is started (step S201). Here, as in step S101, the patient 100 is already fixed to the bed 500, the ultrasonic probe 107 is pressed by the fixing jig 107a, and the respiratory state of the patient 100 is measured by the respiratory state measuring unit 110. It is assumed that the preparations for have been completed.

Next, transmission of ultrasonic waves toward the body of the patient 100 by the ultrasonic probe 107 and signals of ultrasonic waves reflected and scattered from the patient body by the ultrasonic transmission / reception unit 108 are collected (step S202).

Next, the ultrasonic image constructing unit 109 constructs an actual ultrasonic image using the collected ultrasonic signals (step S203).

Next, the respiratory state of the patient 100 is measured using the respiratory state measuring unit 110 (step S204).

Here, Steps S202 and S203 for constructing an actual ultrasonic image and Step S204 for measuring a respiratory state may be performed simultaneously, or the order may be switched.

Next, referring to the database 106, the pseudo ultrasonic image stored in the database 106 is read out (step S205). In selecting the pseudo-ultrasonic image in this step, using the respiratory state of the patient measured in step S204, the pseudo-ultrasonic image generated from the 3D information acquired in the same respiratory state, the 3D information acquired in the approximate respiratory state From the pseudo-ultrasonic image generated from the above, or the pseudo-ultrasonic image generated by interpolation from the 3D information acquired in the approximate breathing state, is appropriately selected.

Next, the real ultrasonic image constructed in step S203 is compared with the pseudo ultrasonic image selected in step S205, and a matching pseudo ultrasonic image is searched (step S206).

Next, it is determined whether or not the search in step S206 is successful (step S207). If it is determined that the search is successful, the process proceeds to step S208A, the body tissue position corresponding to the pseudo-ultrasonic image is read from the database 106, and is output to the body tissue position output unit 112 (step S208A). In contrast, if it is determined in step S207 that the search has failed, an error signal is output to the body tissue position output unit 112 (step S208B).

FIG. 8 is a flowchart showing details of the search method for the real ultrasonic image and the pseudo ultrasonic image in step S206 described above.

First, processing is started (step S301).

Next, the shape, size, and position of the body tissue are extracted from the actual ultrasound image (step S302).

Subsequently, the shape, size, and position of the body tissue are extracted from the pseudo ultrasound image (step S303).

Next, a difference is calculated as an error from the shape, size, and position of the body tissue extracted in steps S302 and S303 (step S304). For example, the sum of squares of the difference between the values can be used as the error. In this step S304, the error is further compared with a preset threshold value to determine whether it matches or does not match.

If it is determined in step S304 that the error is equal to or smaller than the threshold value, it is considered that they match, the process proceeds to step S306, the pseudo ultrasonic image is output to the body tissue position output unit 112, and the process ends (step S307). ).

On the other hand, if it is determined in step S304 that the error is larger than the threshold value, it is considered that they do not match, and the process returns to step S302 to execute a comparison between a different pseudo ultrasonic image and a real ultrasonic image.

Note that the search method of the real ultrasonic image and the pseudo ultrasonic image in step S206 is not limited to the procedure shown in FIG. 8, and for example, the correlation coefficient between the real ultrasonic image and the pseudo ultrasonic image is calculated and appropriately used in advance. When the determined threshold exceeds the correlation coefficient, it can be determined that both match, and when the correlation coefficient is equal to or less than the threshold, it can be determined that they do not match.

Further, it is determined whether or not the pixel size and pixel shape obtained in the pseudo ultrasonic image and the real ultrasonic cross-sectional image are different, and by interpolating either one of the pixel data, the real ultrasonic image and the pseudo ultrasonic wave are interpolated. The resolution can be matched with the image.

Using the pseudo ultrasonic image obtained in this way, the 3D position related to the tissue position in the patient 100 can be output from the corresponding patient 3D information in step S208 described above.

Next, the effect of this embodiment will be described.

The above-described body tissue position measurement apparatus according to the first embodiment of the present invention includes the respiratory synchronization 3D information acquisition unit 101 that acquires 3D information of the patient 100 synchronized with respiration, and the 3D acquired by the respiratory synchronization 3D information acquisition unit 101. A patient 3D information storage unit 102 that stores information, an ultrasound propagation model creation unit 103 that creates an ultrasound propagation model using the patient 3D information stored in the patient 3D information storage unit 102, and an ultrasound propagation model creation unit The ultrasonic image simulation unit 105 that simulates the propagation of ultrasonic waves in the ultrasonic propagation model created in 103 to calculate a pseudo ultrasonic image, and the pseudo ultrasonic image calculated by the ultrasonic image simulation unit 105 A database 106 stored in association with the patient 3D information, and an ultrasonic wave is transmitted toward the body of the patient 100, and the patient 100 An ultrasound image that constitutes an actual ultrasound image from ultrasound received by the ultrasound probe 107 and the ultrasound transceiver 108, and an ultrasound probe 107 and ultrasound transceiver 108 that receive ultrasound returning from the body Based on the respiratory state measured by the constituent unit 109, the respiratory state measuring unit 110 that measures the respiratory state of the patient 100, and the respiratory state measuring unit 110, the actual ultrasonic image and database configured by the ultrasonic image constituent unit 109 A body tissue position calculation unit 111 that compares the pseudo ultrasound image stored in 106 and calculates the tissue position in the body of the patient 100 is provided.

As a result, the position of the tissue in the body of the patient 100 using ultrasonic waves with low invasiveness can be accurately measured in real time, and the system is complicated as in the case of using a three-dimensional ultrasonic probe or the like. Therefore, the body tissue position in the patient can be measured accurately and in real time.

The body tissue position changing unit 104 is further provided as an input device for changing the position of the body tissue in the ultrasound propagation model created by the ultrasound propagation model creating unit 103 and performing a simulation based on the changed ultrasound propagation model. Therefore, detailed information that could not be picked up at the time of treatment planning can be set, and a more accurate ultrasonic propagation model can be set, so that a more accurate measurement of the in-vivo tissue position becomes possible.

Furthermore, the body tissue position calculation unit 111 extracts the shape, size, and position of the body tissue in each of the real ultrasound image and the pseudo ultrasound image by image processing, and detects differences in shape, size, and position as errors. And calculating the tissue position in the body of the patient 100 by comparing the calculated error with a preset threshold value, so that the comparison between the real ultrasound image and the pseudo ultrasound image can be performed with high accuracy. It is possible to measure the position of the body tissue more accurately.

In addition, the body tissue position calculation unit 111 calculates a correlation coefficient between the real ultrasound image and the pseudo ultrasound image, and compares the calculated correlation coefficient with a preset threshold value so that the inside of the patient 100 is within the body. By calculating the tissue position, the comparison between the real ultrasonic image and the pseudo ultrasonic image can be performed with high accuracy, and the accurate measurement of the in-vivo tissue position can be performed.

Furthermore, the body tissue position calculation unit 111 matches the resolution of the real ultrasound image and the pseudo ultrasound image with any one of the pixel data by interpolation, so that the real ultrasound image and the pseudo ultrasound image with higher accuracy can be obtained. Comparison with a sound image is possible, and a more accurate measurement of a body tissue position is possible.

<Second embodiment>
A radiotherapy apparatus according to a second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a diagram showing a configuration concept of the radiation irradiation apparatus according to the second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. The same applies to the following embodiments.

As shown in FIG. 9, the radiotherapy apparatus of the present embodiment is an apparatus for specifying a target body tissue position and irradiating the target with radiation, and the body tissue position measurement of the first embodiment. In addition to the apparatus, a radiation irradiation unit (irradiation device) 901 for irradiating the target with radiation and a radiation control unit 902 are further provided.

The radiation control unit 902 receives the body tissue position calculated by the body tissue position calculation unit 111 as a signal, and controls the radiation irradiation unit 901 to irradiate the patient 100 with radiation 903 such as X-rays and particle beams. To control. Thereby, it is comprised so that it may concentrate on the area | region of the treatment object site | part planned by the treatment plan, and may irradiate.

In the radiotherapy apparatus of the present embodiment, the respiratory state of the patient 100 is monitored by the respiratory state measurement unit 110 and the like to identify the respiratory phase, select an appropriate ultrasonic propagation model, and configure a pseudo ultrasonic image. . Thereby, it is possible to specify an appropriate timing for the treatment target site to pass through the target coordinate region, and to start or stop the radiation irradiation with high accuracy.

Further, it is possible to control the radiation 903 according to the movement of the treatment target site by repeatedly executing the calculation of the body tissue position at an appropriate frame rate.

As in the radiotherapy apparatus according to the second embodiment of the present invention, measurement is performed using the in-vivo tissue position measurement apparatus according to the first embodiment, the radiation irradiation unit 901 that irradiates the target with radiation, and the in-vivo tissue position measurement apparatus. And a radiation control unit 902 for controlling the radiation irradiation position in the radiation irradiation unit 901 based on the position of the in-vivo tissue, thereby reducing the exposure dose due to the X-ray irradiation resulting from the specification of the position of the body tissue being treated It is possible to perform radiotherapy with high accuracy corresponding to patient movement such as breathing.

<Third embodiment>
The in-vivo tissue position measuring apparatus, radiotherapy apparatus, and in-vivo tissue position measuring method of the third embodiment of the present invention will be described with reference to FIG. FIG. 10 is a conceptual diagram of an ultrasonic cross-sectional image in the body tissue position measurement apparatus of the present embodiment.

In this embodiment, the in-vivo tissue position measuring apparatus in the first embodiment further includes an ultrasonic reflector 1001 that strongly reflects ultrasonic waves to be embedded in the body of the patient 100.

Furthermore, when measuring the position of the body tissue, the ultrasound reflector 1001 is embedded in the body of the patient 100, and the ultrasound reflector 1001 is used as an index indicating the position of the body tissue to be measured. By calculating the position, the tissue position in the body of the patient 100 is calculated.

Generally, it is known that a living tissue is a soft tissue, and the attenuation of ultrasonic waves is large, and the difference in acoustic impedance between the tissues in the body is small, so that ultrasonic reflection hardly occurs. For this reason, there may be a case where a sufficient reflected signal cannot be obtained from the body tissue that is the position calculation target, and a clear real ultrasound image cannot be obtained.

Therefore, in the present embodiment, in the stage of acquiring respiration-synchronized 3D information before the creation of an ultrasonic propagation model, an ultrasonic reflector 1001 having a greatly different acoustic impedance from that of a living tissue in advance in the body of the patient 100 is particularly focused. It is embedded near the body tissue such as the target site. As a result, a clearer real ultrasonic image can be obtained.

Then, an ultrasonic propagation model 401A in which the ultrasonic reflector 1001 is reflected is created, and relative coordinates between the embedded ultrasonic reflector 1001 and the body tissue whose position is to be calculated are calculated in advance. Further, when comparing the real ultrasonic image and the pseudo ultrasonic image, an error such as the shape, size, position, etc. of the ultrasonic reflector 1001 is calculated, or when calculating the correlation coefficient, the ultrasonic reflector 1001 is used. Or use it.

In this embodiment, when calculating the position of the body tissue of interest, the relative coordinates calculated in advance are added to the absolute coordinates of the ultrasonic reflector 1001.

In the body tissue position measuring apparatus according to the third embodiment of the present invention, the same effects as those of the body tissue position measuring apparatus according to the first embodiment described above can be obtained.

Furthermore, an ultrasonic reflector 1001 to be embedded in the body of the patient 100 is further provided, and the in-vivo tissue position calculation unit 111 uses the ultrasonic reflector 1001 reflected in the pseudo-ultrasonic image and the actual ultrasonic image to perform tissue in the patient 100. By calculating the position, the comparison between the real ultrasonic image and the pseudo ultrasonic image can be performed with higher accuracy, and more accurate measurement of the in-vivo tissue position can be performed.

<Others>
In addition, this invention is not limited to said Example, Various modifications are included. The above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Moreover, it is also possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 100 ... Patient 101 ... Respiration synchronous 3D information acquisition part 102 ... Patient 3D information storage part 103 ... Ultrasonic propagation model creation part 104 ... In-vivo tissue position change part 105 ... Ultrasound image simulation part 106 ... Database 107 ... Ultrasonic probe DESCRIPTION OF SYMBOLS 108 ... Ultrasonic transmission / reception part 109 ... Ultrasound image structure part 110 ... Respiration state measurement part 111 ... In-vivo tissue position calculation part 112 ... In-vivo tissue position output part 201 ... Tumor 202 ... Ultrasound

scanning cross section

301A, 301B ... With a certain respiratory phase

Real ultrasound images

302A, 302B ...

organs

303A, 303B drawn in the real ultrasound image ...

tumors

401, 401A drawn in the real ultrasound image ... ultrasonic propagation model 501 ...

patient 3D information

501A, 501B ...

Pseudo-ultrasound images

502A, 502B at a certain respiratory phase, organ 503A drawn in patient 3D information, 03B ... to be measured drawn into the patient 3D information tumor 901 ... radiation emission unit 902 ... radiation control unit 903 ... radiation 1001 ... ultrasonic reflector

Claims

A body tissue position measuring device that measures the position of a tissue in a patient body by ultrasound,
A respiratory synchronization 3D information acquisition unit for acquiring 3D information of the patient synchronized with the breath;
A patient 3D information storage unit for storing the 3D information acquired by the respiratory synchronization 3D information acquisition unit;
An ultrasound propagation model creation unit that creates an ultrasound propagation model using the patient 3D information stored in the patient 3D information storage unit;
An ultrasonic image simulation unit that simulates the propagation of ultrasonic waves in the ultrasonic propagation model created in the ultrasonic propagation model creation unit and calculates a pseudo ultrasonic image;
A database for storing the pseudo ultrasonic image calculated by the ultrasonic image simulation unit in association with the patient 3D information;
An ultrasonic transmission / reception unit that transmits ultrasonic waves toward the patient's body and receives ultrasonic waves returning from the patient's body;
An ultrasound image constructing unit that constructs an actual ultrasound image from the ultrasound received by the ultrasound transmitting and receiving unit;
A respiratory state measuring unit for measuring the respiratory state of the patient;
Based on the respiratory state measured by the respiratory state measuring unit, the real ultrasonic image configured by the ultrasonic image constructing unit is compared with the pseudo ultrasonic image stored in the database, and the body of the patient is compared. And a body tissue position calculation unit for calculating the tissue position of the body.
The body tissue position measuring device according to claim 1,
An internal tissue further comprising an input device for changing the position of the internal tissue in the ultrasonic propagation model created by the ultrasonic propagation model creating unit and causing a simulation based on the changed ultrasonic propagation model Position measuring device.
The body tissue position measuring device according to claim 1,
The body tissue position calculation unit extracts the shape, size, and position of the body tissue in each of the real ultrasound image and the pseudo ultrasound image by image processing, and calculates a difference in the shape, size, and position. An in-vivo tissue position measuring device that calculates as an error and compares the calculated error with a preset threshold value to calculate a tissue position in the patient.
The body tissue position measuring device according to claim 1,
The body tissue position calculation unit calculates a correlation coefficient between the real ultrasonic image and the pseudo ultrasonic image, and compares the calculated correlation coefficient with a preset threshold value to thereby calculate the internal body position of the patient. An in-vivo tissue position measuring apparatus characterized by calculating a tissue position.
The body tissue position measuring device according to claim 1,
The in-vivo tissue position calculation unit matches the resolution of the real ultrasonic image and the pseudo ultrasonic image by interpolating any one of the pixel data.
The body tissue position measuring device according to claim 1,
Further comprising an ultrasonic reflector for implantation in the patient's body;
The in-vivo tissue position calculation unit calculates a tissue position in the patient's body using the ultrasonic reflector reflected in the pseudo-ultrasonic image and the real ultrasonic image.
A radiotherapy apparatus that identifies a target body tissue position and irradiates a target with radiation,
A body tissue position measuring device according to claim 1;
An irradiation device for irradiating the target with the radiation;
A radiation therapy apparatus comprising: a radiation control unit that controls a radiation irradiation position in the irradiation apparatus based on a body tissue position measured using the body tissue position measurement apparatus.
A body tissue position measurement method for obtaining a body tissue position in a patient by ultrasound,
Obtaining 3D information of the patient synchronized with breathing;
Creating an ultrasonic propagation model using the acquired 3D information;
Simulating the propagation of ultrasound in the created ultrasound propagation model to create a pseudo ultrasound image;
Storing the created pseudo-ultrasonic image in a database in association with the patient 3D information;
Transmitting ultrasound toward the patient's body and receiving ultrasound returning from the patient's body, and constructing an actual ultrasound image from the received ultrasound;
Measuring the respiratory state of the patient;
Comparing the actual ultrasonic image and the pseudo ultrasonic image based on the measured respiratory state of the patient, and calculating a tissue position in the patient's body. Position measurement method.
The body tissue position measurement method according to claim 8,
Calculating the body tissue position comprises:
Extracting the shape, size, and position of the body tissue in each of the real ultrasound image and the pseudo ultrasound image by image processing by image processing; and
Calculating the difference in shape, size and position as an error;
And comparing the error with a preset threshold value to determine whether or not the real ultrasonic image and the pseudo ultrasonic image match each other.
The body tissue position measurement method according to claim 8,
Calculating the body tissue position comprises:
Calculating a correlation coefficient between the real ultrasound image and the pseudo ultrasound image;
Determining whether the real ultrasound image and the pseudo ultrasound image match by comparing the correlation coefficient with a preset threshold value. Method.
The body tissue position measurement method according to claim 8,
Calculating the body tissue position comprises:
A method of measuring a body tissue position, further comprising: matching the resolution of the real ultrasonic image and the pseudo ultrasonic image by interpolating any one of the pixel data.
The body tissue position measurement method according to claim 8,
The step of constructing the real ultrasound image includes
Implanting an ultrasound reflector in the patient's body;
Calculating the tissue position in the patient's body using the ultrasonic reflector reflected in the pseudo-ultrasonic image and the real ultrasonic image, using the ultrasonic reflector as an index indicating the position of the body tissue to be measured. And a body tissue position measuring method characterized by comprising: