JP2018175688A - Body tissue position measuring apparatus, radiation therapy apparatus, and body tissue position measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a body tissue position accurately and in real time using a low-invasive ultrasonic wave without complicating a system.SOLUTION: A body tissue position measuring apparatus includes: an ultrasonic wave propagation model creating part 103 for creating an ultrasonic wave propagation model using 3D information on a patient 100 synchronized with the respiration; an ultrasonic image simulation part 105 for simulating the propagation of the ultrasonic wave in the ultrasonic wave propagation model and calculating a pseudo ultrasonic image; a database 106 for storing the pseudo ultrasonic image in association with the 3D information on the patient; and a body tissue position calculation part 111 for comparing an actual ultrasonic image composed by an ultrasonic image composition part 109 to the pseudo ultrasonic image stored in the database 106 based on a status of the respiration measured by a respiration state measuring part 110, and calculating the body tissue position of the patient 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an internal tissue position measuring device and a radiotherapy device for measuring a specific tissue position in a patient's body by ultrasound, and an internal tissue position measuring method.

  Patent Document 1 and Patent Document 2 disclose methods of measuring the position of internal tissues.

  According to Patent Document 1, the radiation of high accuracy is detected by detecting the behavior of the treatment target site caused by the patient's breathing, pulsation or body movement without particularly causing the enlargement of the device itself or the excessive complication. In order to provide a non-invasive and highly safe radiation treatment apparatus and the like capable of performing It is determined whether the correlation value between both ultrasound images is greater than or equal to a predetermined value by comparing the therapeutic ultrasonic image captured in real time with the ultrasonic image for treatment planning. It is described that the irradiation means is controlled such that the irradiation of the treatment site is performed only when

  In Patent Document 2, for the purpose of providing an ultrasonic medical system which outputs appropriate information regarding tissue position, the ultrasonic diagnostic apparatus outputs echo data to the host controller, and the tissue coordinate computing unit performs three-dimensional search. The coordinate information of the tumor whose origin is the probe is calculated, and the probe coordinate operation unit calculates the coordinate information of the three-dimensional probe whose origin is the X-ray irradiation device which is the reference position. Calculate the coordinate information of the tumor with the X-ray irradiator as the origin based on the coordinate information of the tumor with the 3D probe as the origin and the coordinate information of the 3D probe with the X-ray irradiator as the origin Output to an X-ray irradiator.

Japanese Patent Application Laid-Open No. 2003-117010 Japanese Patent Laid-Open No. 2004-000499

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

  Among these, radiation therapy is a treatment method that kills cancer cells by irradiating high-dose radiation to the internal tissues of the patient's treatment site, and radiation can be concentrated on the treatment site to act. , A side effect is relatively mild way.

  In order to efficiently carry out radiation therapy, it is important that the area to which radiation is concentrated and the area in which the cancer tumor to be treated match be precisely matched.

  In the conventional radiotherapy apparatus, the position of the internal tissue which 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 thereon. Thereafter, the patient is fixed on the treatment table of the radiation treatment apparatus, and radiation characteristics are irradiated to the internal tissue of the patient to be treated by controlling the radiation characteristics such as radiation direction and intensity.

  However, due to the patient's own breathing during radiation irradiation, it has been an issue to treat with high precision that the treatment target site of the patient moves from the radiation irradiation position planned in advance.

  In order to solve this problem, a marker made of gold or the like is embedded in the patient's body in advance, and this marker is imaged by an X-ray transmission image and tracked to detect the movement of the treatment target site, and advance treatment planning A method of treating with high accuracy has been established by using it for radiation control at the time of and irradiation.

  On the other hand, the realization of a less invasive internal tissue position measuring device capable of suppressing the exposure dose due to X-ray irradiation during treatment and responding to the patient's movement such as respiration is for further reduction of exposure dose. It is desired. One of the less invasive methods is a method using an ultrasound image.

  In Patent Document 1, instead of a marker and an X-ray, radiation is irradiated at a timing when the correlation value between an ultrasound image acquired in a simultaneous phase with a CT image acquired in advance and an ultrasound image acquired during treatment is high. There is a description of a treatment device.

  The radiotherapy apparatus described in Patent Document 1 is configured to irradiate radiation using a treatment planning ultrasound image acquired in a simultaneous phase with a CT image acquired in advance and a treatment ultrasound image acquired during treatment. By controlling it, it is possible to make treatment less invasive. However, radiation is applied at the timing when a treatment planning ultrasound image having a high correlation value with the treatment ultrasound image is obtained, and the position of the internal tissue being treated is not specified from the ultrasound image. Therefore, there is a problem that there may be an error in the position to be treated and the actual treatment site.

  The ultrasonic medical system described in Patent Document 2 specifies the coordinates of a tumor in a patient's body using a three-dimensional ultrasonic image obtained using a three-dimensional ultrasonic probe, and transmits the coordinate information to the X-ray irradiation apparatus. It is made to output. However, it takes time to record and process ultrasonic waveforms, and the system becomes complicated.

  Further, in paragraph (0024) of Patent Document 2, in place of the three-dimensional ultrasonic probe, transmission and reception may be performed only in the two-dimensional scanning plane using the two-dimensional ultrasonic probe. There is a description. However, since the target tissue including the tumor moves not only in the cross section of the ultrasound image but also in the direction out of the cross section, it is actually only necessary to use a two-dimensional ultrasound probe instead of the three-dimensional ultrasound probe. There is a problem that errors in the tumor position and the measurement position may occur.

  The present invention has been made in view of the above problems, and it is an internal tissue position capable of accurately and in real time measuring the position of internal tissue without complicating the system by using a low invasive ultrasonic wave. It is an object of the present invention to provide a measurement device and a radiation treatment device, and a method of measuring the position of an internal tissue.

  The present invention includes a plurality of means for solving the above problems, one example of which is an internal tissue position measuring device for measuring the position of tissue in a patient's body by ultrasonic waves, wherein the patient is synchronized with respiration. A 3D information acquisition unit for acquiring 3D information of a patient, a patient 3D information storage unit for storing the 3D information acquired by the 3D information acquisition unit for respiratory synchronization, 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 simulation of ultrasonic wave propagation in the ultrasonic wave propagation model created by the ultrasonic wave propagation model creation unit An ultrasonic image simulation unit that calculates the image, and the pseudo ultrasonic image calculated by the ultrasonic image simulation unit in association with the patient 3D information and stored Database, ultrasound transmitting and receiving units for transmitting ultrasound toward the patient's body, and receiving ultrasound returning from the patient's body, and a real ultrasound image from the ultrasound received by the ultrasound transmitting and receiving unit The ultrasonic image constructing unit configured based on the ultrasonic image constructing unit, the respiratory state measuring unit measuring the respiratory state of the patient, and the ultrasonic image constructing unit based on the respiratory state measured by the respiratory state measuring unit And an in-vivo tissue position calculating unit for calculating a tissue position in the patient's body by comparing the sound wave image with the pseudo-ultrasound image stored in the database.

  According to the present invention, less invasive ultrasound can be used to accurately and in real time measure the position of internal tissue in a patient without complicating the system.

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

  Hereinafter, an embodiment of the internal tissue position measuring apparatus and radiation treatment apparatus of the present invention and the internal tissue position measuring method will be described with reference to the drawings.

First Embodiment
A first embodiment of a body tissue position measuring device and a body tissue position measuring method of the present invention will be described with reference to FIGS. The same reference numerals as in FIGS. 1 to 8 denote the same parts.

  FIG. 1 is a conceptual view of the configuration of the internal tissue position measuring apparatus according to the present embodiment, FIG. 2 is a schematic view showing changes in internal tissue position in the patient, and FIGS. 3A and 3B are changes in internal tissue position in the patient Fig. 4 is a schematic view showing a change in an ultrasonic cross-sectional image due to the present invention, Fig. 4 is a conceptual view showing an ultrasonic wave propagation model generated by the present embodiment, and Figs. 5A and 5B are internal tissue by comparison of an actual ultrasonic image FIG. 6 is a flowchart showing a method of constructing a database according to the present embodiment, FIG. 7 is a flowchart showing a method of measuring the position of an internal tissue according to the present embodiment, and FIG. 8 is an actual ultrasound image according to the present embodiment It is a flowchart which shows the comparison method with a pseudo | simulation ultrasound image.

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

  In FIG. 1, the internal tissue position measuring device is a device for measuring the three-dimensional internal tissue position of the patient 100 fixed on the bed 500 and laid down by ultrasonic waves, and mainly, the respiratory synchronous 3D information acquisition unit 101, Patient 3D information storage unit 102, ultrasound propagation model creation unit 103, internal tissue position change unit (input device) 104, ultrasound image simulation unit 105, database 106, ultrasound probe 107, ultrasound transmission / reception unit 108, A sound wave image constructing unit 109, a respiratory state measuring unit 110, an in-vivo tissue position calculating unit 111, and an in-vivo tissue position outputting unit 112 are provided.

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

  The ultrasound probe 107 receives an electrical signal from the ultrasound transmission / reception unit 108, excites ultrasound, and transmits the ultrasound into the body of the patient 100. Further, it receives an ultrasonic wave returned from the body of the patient 100 by reflection, scattering or the like, converts it into an electric signal, and transmits it to the ultrasonic wave transmitting / receiving unit 108. The ultrasound transmission / reception unit 108 amplifies the electrical signal received from the ultrasound probe 107 and sends it to the ultrasound image construction unit 109.

  Generally, ultrasonic elements are arranged in a line in the ultrasonic probe 107, and by controlling the respective excitation timing by the ultrasonic transmitting / receiving unit 108, it is possible to scan the focus position of ultrasonic waves, etc. It has become.

  The ultrasound image configuration unit 109 acquires an ultrasound image in the ultrasound scanning range by combining the ultrasound reception signals by reflection, scattering, and the like received by the ultrasound transmission / reception unit 108.

  Here, FIG. 2 is a schematic view showing how the position of the internal tissue in the patient's body changes. When the center of the tumor 201 to be measured is present in the ultrasound scan cross section 202, the position of the internal tissue can be easily calculated from the acquired ultrasound image. However, as shown in FIG. 2, when the position of the tumor 201 changes with the respiration of the patient 100, the ultrasonic scan cross-section 202 and the center of the tumor 201 do not necessarily coincide, and often do not coincide.

  FIGS. 3A and 3B schematically show changes in ultrasonic cross-sectional images due to changes in the position of internal tissue in a patient.

  When the ultrasonic scan section 202 and the center of the tumor 201 coincide with each other, images of the organ 302A and the tumor 303A are drawn in the actual ultrasonic image 301A as shown in FIG. 3A.

  On the other hand, when the ultrasonic scan section 202 and the center of the tumor 201 do not match, 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 are obtained by drawing the tumor 201 which is the same internal tissue, but the relative positions of the actual ultrasound image in the organs 302A and 302B. The position and size are drawn differently. Only from such a real ultrasound image 301A and a real ultrasound image 301B, it is only possible to estimate the internal tissue position in a two-dimensional image, and it is difficult to calculate a three-dimensional internal 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 in-vivo tissue positions are created by simulation using the above-mentioned 3D information. . Furthermore, the ultrasonic image obtained by this simulation and the in-vivo tissue position in the 3D information described above are stored in the database in association with each other. Then, when imaging the patient's body using ultrasound to calculate the position of body tissue, the above-mentioned database is referred to, and an ultrasound image obtained by measurement and an ultrasound image obtained by simulation are calculated. By comparison, the corresponding internal tissue position is found. Hereinafter, the configuration for creating an ultrasound image by simulation and the operation thereof will be described.

  In FIG. 1, for example, at a timing synchronized with respiration, the respiration synchronized 3D information acquisition unit 101 captures a CT image including at least an internal tissue to be subjected to position calculation. By imaging CT images at a plurality of timings for each respiratory phase, information on the internal tissue position of the patient 100 for each respiratory phase and other tissues is acquired as 3D information. At this time, the ultrasound probe 107 may produce an artifact of the CT image. In such a case, in place of the ultrasound probe 107, a dummy probe with few artifacts is simulated and fixed to simulate pressing of the body surface by the ultrasound probe 107 when acquiring 3D information. It is desirable to hold the tool 107a and acquire a CT image in that state.

  The information acquired by the respiratory synchronous 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 wave propagation model creating unit 103 superimposes in the patient body divided into appropriate small areas (meshes) in accordance with 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 wave propagation model creating unit 103, physical quantities necessary to calculate ultrasonic wave propagation such as density and speed of sound of each small area or acoustic impedance by the operator using the internal tissue position changing unit 104 described later and the like. The ultrasonic wave propagation model 401 is created in response to the input of the combination setting. The operator determines fat, muscle, blood vessels, bones, organs and the like from the patient 3D information, and sets physical quantities in each small area 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, muscles and organs is about 1530 to 1630 m / s, and the speed of sound in bone is about 2700 to 4100 m / s. Set an appropriate value according to the state of. In addition, according to the brightness of the CT image, fat, muscle, blood vessels, bones, organs, etc. are automatically discriminated by the ultrasonic wave propagation model creating unit 103, and setting is performed by setting physical quantities in the respective saving areas according to the type of tissue. It can be automated.

  In addition, the ultrasonic wave propagation model creating unit 103 determines which cross section of the 3D model to obtain an ultrasonic image of the 3D model based on the information of the position where the ultrasonic wave probe 107 is actually installed and the transmission direction of the ultrasonic wave. decide.

  With respect to the ultrasonic wave propagation model created by the ultrasonic wave propagation model creating unit 103, the internal tissue position changing unit 104 determines the body tissue to be measured, or other fats, muscles, blood vessels, bones, organs, etc. It is a device for the operator or the like to arbitrarily change the instruction. For example, in the ultrasonic wave propagation model displayed on the screen of the computer, an operation means such as operation of a mouse or an input means such as text data can be used.

  The ultrasonic image simulation unit 105 is generated in the ultrasonic wave propagation model generation unit 103 using a means such as ultrasonic wave propagation analysis, or in the ultrasonic wave propagation model changed or corrected by the in vivo tissue position changing unit 104, Analyzes the propagation path of the ultrasonic wave incident into the patient's body from the specified ultrasonic probe position, simulates the reflection and scattering of the ultrasonic wave in the patient's body, and simulates a pseudo ultrasonic image (a pseudo ultrasonic wave Calculate the image). For propagation analysis, finite element method, difference method, and ray tracing methods are 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 includes the position of the internal tissue designated by the internal tissue position changing unit 104 and the patient's respiratory phase when the respiratory synchronous 3D information acquiring unit 101 acquires the pseudo ultrasonic image obtained by the ultrasonic image simulation unit 105. Save in a state associated with information.

  The respiratory state measurement unit 110 is a device or device that measures the respiratory state of the patient 100. The respiratory state measurement unit 110 may be, for example, a device or device that identifies a respiratory phase by monitoring the movement of the body surface of the patient 100 using a laser range finder, measuring the exhalation of the patient, or the like. Various other methods can be adopted as the respiratory condition 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 ultrasound image construction unit 109, and the respiration state measurement unit 110, and based on the respiration state measured by the respiration state measurement unit 110, the ultrasound image construction unit 109 performs real time. The position of the tissue in the body of the patient 100 is calculated by comparing the actual ultrasonic image acquired in the above and the simulated ultrasonic image obtained in the simulation stored in the database 106. Hereinafter, an example of the comparison method will be described using FIGS. 5A and 5.

  In the internal tissue position measuring apparatus of this embodiment, as described above, the database 106 stores the patient 3D information 501 at a certain breathing phase and the pseudo ultrasonic images 501A, 501B,. A simulated ultrasound image comparable to the actual ultrasound image obtained during the sound measurement is obtained by simulation on specific cross sections of the patient 3D information.

  Therefore, when the ultrasound scan cross section coincides with the center of the body tissue, as shown in FIG. 5A, the pseudo ultrasound in the case where the ultrasound scan cross section stored in the database 106 coincides with the center of the body tissue When it is determined that the image 501A is retrieved from the database 106 and the organ 502A and the tumor 503A depicted in the pseudo-ultrasound image 501A are compared with the organ 302A and the tumor 303A depicted in the actual ultrasonic image 301A The position of the tissue in the body of the patient 100 is calculated using the information of the actual ultrasonic image 301A.

  On the other hand, if the ultrasound scanning cross section does not match the center of the internal tissue, as shown in FIG. 5B, it is stored in the database 106 based on the information of the respiratory phase at that time measured by the respiratory state measuring unit 110. The simulated ultrasound image 501B in the case where the ultrasound scanning cross section does not match the center of the internal tissue is retrieved from the database 106, and the organ 502B and the tumor 503B depicted in the simulated ultrasound image 501B are displayed as the actual ultrasound image 301B. The position of the tissue in the body of the patient 100 is calculated using the information of the actual ultrasonic image 301B when it is determined to match, in comparison with the organ 302B and the tumor 303B depicted inside.

  Here, when comparing the simulated ultrasound image and the actual ultrasound image in the internal tissue position calculation unit 111, for example, the shape, size, and the like of the internal tissue in the cross-sectional image of the internal tissue to be measured by image processing. Several parameters, such as position, can be extracted and their differences compared quantitatively. For example, the difference between the two may be calculated as an error, and the calculated error may be compared with a predetermined threshold, determined as matching when smaller than the threshold, and determined as not matching when the error is equal to or greater than the threshold. it can. If it is determined that the two do not match, another intracorporeal tissue position previously stored in the database 106 is specified, and the ultrasound cross-sectional image obtained by simulation is referred to, and the comparison is executed again. Search for matching data.

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

  Here, when comparing the simulation and the actual ultrasound cross-sectional image in the in-vivo tissue position calculation unit 111, it is assumed that the pixel size and the pixel shape obtained by the pseudo ultrasound image and the actual ultrasound cross-sectional image are different. For example, if the shape, size, position, and the like in the cross-sectional image of the internal tissue greatly differ in pixel size, the comparison may be difficult 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 both coincide with each other to a certain level.

  Therefore, the internal tissue position calculation unit 111 first compares the resolution of the pseudo ultrasound image and the resolution of the actual ultrasound image, and interpolates pixel data for either one of the pseudo ultrasound image and the actual ultrasound image. It is preferable to match the resolutions of the two images. As the method of pixel interpolation, nearest neighbor interpolation, bilinear interpolation, bicubic interpolation, etc. are generally known, and an appropriate method can be selected according to the target position calculation accuracy. The image to be interpolated may be either image, but it is desirable to fit the lower resolution image to the higher resolution image.

  If matching data can be found, the internal tissue position calculation unit 111 outputs information on the corresponding internal tissue position to the internal tissue position output unit 112. The output method may be, for example, displaying the relative position from the reference coordinates numerically on the 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 such as wired or wireless transmission as a signal. Besides this, various methods can be adopted for the output method according to the purpose of use of the calculated internal tissue position, and therefore, the example shown here does not limit the present invention.

  The ultrasonic wave propagation model creation unit 103, the ultrasonic image simulation unit 105, the ultrasonic wave transmission / reception unit 108, the ultrasonic image formation unit 109, and the internal tissue position calculation unit 111 described above are a computer, a field-programmable gate array (FPGA), etc. This can be realized by loading a program in to execute calculations.

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

  Next, with reference to FIGS. 6 to 8, a method for measuring the position of a body tissue according to the present embodiment, which suitably uses the above-described body tissue position measuring device, will be described.

  First, a method of creating an ultrasonic wave propagation model in the method of measuring the position of a body tissue according to the present embodiment will be described with reference to FIG.

  In FIG. 6, first, the process is started (step S101). In this step, it is assumed that the patient 100 is already fixed to the bed 500. In addition, the ultrasound probe 107 with the fixing jig 107a or a dummy probe with reduced artifacts is pressed on the patient 100 to simulate actual ultrasound image acquisition, and the patient 100 by the respiratory synchronous 3D information acquisition unit 101 or the like. It is assumed that the preparation of the measurement of the respiratory condition of has been completed.

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

  Next, the ultrasonic wave propagation model creation unit 103 creates an ultrasonic wave propagation model (step S103).

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

  Next, with respect to the ultrasound propagation model created in step S103, ultrasound propagation analysis is performed in a region including the position and orientation of the ultrasound probe 107 specified in step S104 and the position of internal tissue, and a simulation image (false An ultrasonic image is created (step S105).

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

  Next, it is determined whether a sufficient amount of pseudo ultrasound images are stored in the database 106 (step S107).

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

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

  In addition, between pseudo | simulation ultrasound images, an accuracy can also be ensured by creating pseudo | simulation ultrasound images by means other than ultrasound propagation analysis by interpolation etc., for example.

  Next, it is determined whether patient 3D information is obtained with the required pattern of respiratory phase (step S108). Similar to the description in the above-described step S107, the number of patterns of the necessary breathing phase to be used as the determination reference is determined according to the final accuracy of calculating the position of the internal body tissue. If it is determined that the number of simulation patterns stored in the database 106 is insufficient, the process returns to step S102, and simulation is performed using other patient 3D information. If it is determined that the number of patterns is sufficient, the process proceeds to step S109, and the process of creating an ultrasonic wave propagation model is ended.

  Although the present embodiment shows an example of collecting a plurality of respiratory states and patterns of internal tissue positions, only measurement results of the patient's breath holding state may be used if sufficient accuracy can be ensured. Also, the human body may be simply modeled as a substance of uniform density and sound velocity.

  Next, among the internal tissue position measuring methods suitably using the aforementioned internal tissue position measuring device, a method of calculating the internal tissue position in the internal tissue position calculating unit 111 will be described using FIGS. 7 and 8.

  First, the process is started (step S201). Here, as in step S101, the patient 100 is already fixed to the bed 500, and the pressing of the ultrasonic probe 107 by the fixing jig 107a, and the measurement of the respiratory state of the patient 100 by the respiratory state measurement unit 110. It is assumed that the preparation of has been completed.

  Next, the ultrasonic probe 107 transmits ultrasonic waves directed into the body of the patient 100, and the ultrasonic wave transmitting / receiving unit 108 collects signals of ultrasonic waves reflected and scattered from the patient's body (step S202).

  Next, a real ultrasonic image is constructed by the ultrasonic image construction unit 109 using the collected ultrasonic signals (step S203).

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

  Here, steps S202 and S203 for constructing an actual ultrasound image and step S204 for measuring a respiratory state may be performed simultaneously, or the order may be changed and may be performed.

  Next, the pseudo-ultrasound image stored in the database 106 is read out with reference to the database 106 (step S205). When selecting a pseudo-ultrasound image in this step, a pseudo-ultrasound image generated from 3D information acquired in the same respiratory state using the patient's respiratory state measured in step S204, 3D information acquired in an approximate respiratory state It selects suitably from the pseudo | simulation ultrasound image produced | generated by interpolation from the pseudo | simulation ultrasound image produced | generated from (3) or the 3D information acquired in the breathing condition to approximate.

  Next, the actual ultrasound image configured in step S203 is compared with the pseudo ultrasound image selected in step S205, and a matching pseudo ultrasound image is searched (step S206).

  Next, it is determined whether 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 in-vivo tissue position corresponding to the pseudo ultrasound image is read from the database 106, and is output to the in-vivo tissue position output unit 112 (step S208A). On the other hand, when it is determined in step S207 that the search is unsuccessful, an error signal is output to the internal tissue position output unit 112 (step S208B).

  FIG. 8 is a flowchart showing the details of the method of searching for the actual ultrasound image and the pseudo ultrasound image in step S206 described above.

  First, the process is started (step S301).

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

  Subsequently, the shape, size, and position of internal 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 step S302 and step S303 (step S304). For example, the square sum of the difference between the values can be used as the error. In step S304, the error is further compared with a preset threshold to determine whether the error is coincident or not.

  If it is determined in step S304 that the error is less than or equal to the threshold value, it is regarded as a match, and the process proceeds to step S306 to output the pseudo ultrasound image to the internal tissue position output unit 112, and then 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 compare different pseudo ultrasound images and actual ultrasound images.

  Note that the method of retrieving the actual ultrasound image and the pseudo ultrasound image in step S206 is not limited to the procedure shown in FIG. 8, and for example, the correlation coefficient between the actual ultrasound image and the pseudo ultrasound image is calculated A method may be adopted in which it is determined that the two coincide with each other if the determined threshold exceeds the correlation coefficient, and that they do not coincide if the correlation coefficient is equal to or less than the threshold.

  In addition, it is determined whether the pixel size and the pixel shape obtained by the pseudo ultrasound image and the actual ultrasound cross-sectional image are different, and either one of the pixel data is interpolated to obtain the actual ultrasound image and the pseudo ultrasound. It is possible to match the resolution with the image.

  Using the pseudo-ultrasound image thus obtained, the 3D position regarding the tissue position in the patient 100 can be output from the corresponding patient 3D information in step S208 described above.

  Next, the effects of this embodiment will be described.

  The in-vivo tissue position measuring apparatus according to the first embodiment of the present invention described above includes the respiratory synchronous 3D information acquiring unit 101 acquiring the 3D information of the patient 100 synchronized with the respiration and the 3D acquired by the respiratory synchronous 3D information acquiring unit 101 Patient 3D information storage unit 102 for storing information, ultrasound propagation model creation unit 103 for creating ultrasound propagation model using patient 3D information stored in patient 3D information storage unit 102, ultrasound propagation model creation unit The ultrasonic image simulation unit 105 that simulates the ultrasonic wave propagation in the ultrasonic wave propagation model created in 103 and calculates a pseudo ultrasonic image, and the pseudo ultrasonic image calculated by the ultrasonic image simulation unit 105 A database 106 for storing in correspondence with patient 3D information, and transmitting ultrasound to the body of the patient 100 An ultrasound image forming an actual ultrasound image from the ultrasound received by the ultrasound probe 107 and the ultrasound transmission / reception unit 108 that receives ultrasound that returns from the inside, the ultrasound probe 107, and the ultrasound transmission / reception unit 108 Based on the respiratory condition measured by the configuration unit 109, the respiratory condition measurement unit 110 for measuring the respiratory condition of the patient 100, and the respiratory condition measurement unit 110, an actual ultrasonic image and database configured by the ultrasonic image configuration unit 109 And an intracorporeal tissue position calculation unit for calculating a tissue position in the body of the patient by comparing the pseudo-ultrasound image stored in the storage unit.

  As a result, the position of the tissue in the body of the patient 100 can be accurately measured in real time using low invasive ultrasound, making the system complicated as in the case of using a three-dimensional ultrasound probe or the like. The position of internal tissue in the patient can be measured accurately and in real time without doing so.

  Further, the internal tissue position changing unit 104 is further provided as an input device for changing the position of the internal tissue in the ultrasonic wave propagation model generated by the ultrasonic wave propagation model generation unit 103 and performing simulation based on the changed ultrasonic wave propagation model. Therefore, since it is possible to set detailed information that could not be picked up at the time of treatment planning and to set a more accurate ultrasonic wave propagation model, more accurate measurement of the position of the internal tissue can be made.

  Furthermore, the in-vivo tissue position calculation unit 111 extracts the shape, size, and position of the in-vivo tissue in each of the actual ultrasound image and the pseudo-ultrasound image by image processing, and the difference between the shape, size, and position is an error. Calculating the position of the tissue in the body of the patient 100 by comparing the calculated error with a preset threshold to calculate the comparison between the actual ultrasound image and the pseudo-ultrasound image with high accuracy. It is possible to perform more accurate measurement of internal tissue position.

  In addition, the internal tissue position calculation unit 111 calculates the correlation coefficient between the actual ultrasound image and the pseudo ultrasound image, and compares the calculated correlation coefficient with a preset threshold value in the body of the patient 100. Also by calculating the tissue position, the comparison between the actual ultrasound image and the pseudo-ultrasound image can be performed with high accuracy, and a more accurate measurement of the tissue position can be performed.

  Furthermore, the internal tissue position calculation unit 111 matches the resolution of the actual ultrasound image and that of the pseudo ultrasound image by interpolation of either one of the pixel data to obtain a more accurate actual ultrasound image and a pseudo ultrasound image. Comparison with acoustic image is possible, and more accurate measurement of internal 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 view showing a configuration concept of a radiation irradiation apparatus according to a second embodiment of the present invention. The same reference numerals are given to the same components as those in the first embodiment, and the description will be omitted. The same applies to the following embodiments.

  As shown in FIG. 9, the radiation treatment apparatus of the present embodiment is an apparatus for specifying the position of the target internal tissue and irradiating the target with radiation, wherein the internal tissue position measurement of the first embodiment is performed. In addition to the apparatus, the apparatus further includes a radiation irradiator (irradiation apparatus) 901 for irradiating radiation to the target and a radiation controller 902.

  The radiation control unit 902 receives the in vivo tissue position calculated by the in vivo tissue position calculation unit 111 as a signal, and controls the radiation irradiation unit 901 to irradiate the radiation position 903 of radiation 903 such as X-ray or particle beam to the patient 100. Control. Thereby, radiation is focused on the area of the treatment target site planned in the treatment plan.

  In the radiotherapy apparatus of this embodiment, the respiratory phase is identified by monitoring the respiratory state of the patient 100 by the respiratory state measurement unit 110 or the like, and an appropriate ultrasonic wave propagation model is selected to construct a pseudo-ultrasound image. . In this way, it is possible to identify the appropriate timing at which the region to be treated passes through the target coordinate region, and to start or stop the radiation irradiation with high accuracy.

  In addition, by repeatedly executing the internal tissue position calculation at an appropriate frame rate, it is possible to control the radiation 903 in accordance with the movement of the region to be treated.

  As in the radiotherapy apparatus according to the second embodiment of the present invention, measurement is performed using the intracorporeal tissue position measuring apparatus according to the first embodiment, a radiation irradiating unit 901 which emits radiation to a target, and the intracorporeal tissue position measuring apparatus The radiation control unit 902 controls the radiation irradiation position in the radiation irradiation unit 901 based on the position of the internal tissue, thereby reducing the exposure dose due to the X-ray irradiation derived from the specification of the position of the internal tissue being treated. Radiation treatment that is accurate and responsive to patient motion such as breathing.

Third Embodiment
An internal tissue position measuring apparatus and a radiotherapy apparatus according to a third embodiment of the present invention, and an internal tissue position measuring method will be described with reference to FIG. FIG. 10 is a conceptual view of an ultrasonic cross-sectional image in the internal tissue position measuring apparatus of the present embodiment.

  In the present embodiment, the internal tissue position measuring apparatus in the first embodiment further includes an ultrasonic reflector 1001 that strongly reflects ultrasonic waves to be implanted in the body of the patient 100.

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

  In general, it is known that living tissue is soft tissue, the attenuation of ultrasonic waves is large, and ultrasonic reflection is less likely to occur because the acoustic impedance difference between the internal tissues is small. For this reason, a sufficient reflected signal from the body tissue targeted for position calculation may not be obtained, and a clear actual ultrasound image may not be obtained.

  Therefore, in the present embodiment, at the stage of acquiring the created respiratory synchronous 3D information before creating the ultrasonic wave propagation model, a treatment that focuses on the ultrasonic wave reflector 1001 having a large difference in biological impedance and acoustic impedance in advance in the patient 100. It is implanted in the vicinity of body tissue such as the target site. This makes it possible to obtain a clearer actual ultrasound image.

  Then, an ultrasonic wave propagation model 401A in which the ultrasonic wave reflector 1001 is reflected is created, and relative coordinates between the embedded ultrasonic wave reflector 1001 and the internal tissue whose position is to be calculated are calculated in advance. In addition, when comparing the real ultrasound image and the pseudo ultrasound image, errors in the shape, size, position, etc. of the ultrasound reflector 1001 are calculated, or the ultrasound reflector 1001 is Use it.

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

  Also in the internal tissue position measuring apparatus of the third embodiment of the present invention, substantially the same effect as the internal tissue position measuring apparatus of the first embodiment described above can be obtained.

  The internal tissue position calculation unit 111 further includes an ultrasound reflector 1001 to be embedded in the body of the patient 100, and the internal tissue position calculation unit 111 uses internal ultrasound reflectors 1001 reflected in the pseudo ultrasound image and the actual ultrasound image. By calculating the position, the comparison between the actual ultrasound image and the pseudo ultrasound image can be performed with higher accuracy, and a more accurate measurement of the internal tissue position can be performed.

<Others>
The present invention is not limited to the above embodiments, and includes various modifications. The above embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. In addition, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, and replace other configurations for part of the configuration of each embodiment.

100 ... patient 101 ... respiration synchronized 3D information acquisition unit 102 ... patient 3D information storage unit 103 ... ultrasound wave propagation model creation unit 104 ... internal tissue position change unit 105 ... ultrasound image simulation unit 106 ... database 107 ... ultrasound probe 108: ultrasound transmitting and receiving unit 109: ultrasound image forming unit 110: breathing state measuring unit 111: internal tissue position calculating unit 112: internal tissue position output unit 201: tumor 202: ultrasonic scanning cross section 301A, 301B: with a certain respiratory phase Real ultrasound images 302A, 302B ... organs 303A, 303B drawn in real ultrasound images ... tumors drawn in real ultrasound images 401, 401A ... ultrasound propagation model 501 ... patient 3D information 501A, 501B ... Pseudo-ultrasound image 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 (12)

An internal tissue position measuring device for measuring the position of tissue in a patient's body by ultrasound, comprising:
A respiratory synchronized 3D information acquisition unit for acquiring 3D information of a patient synchronized with respiration,
A patient 3D information storage unit for storing the 3D information acquired by the respiration synchronized 3D information acquisition unit;
An ultrasonic wave propagation model creation unit for creating an ultrasonic wave propagation model using the patient 3D information stored in the patient 3D information storage unit;
An ultrasonic image simulation unit that simulates ultrasonic wave propagation in the ultrasonic wave propagation model created by the ultrasonic wave propagation model creating unit and calculates a pseudo-ultrasound image;
A database for storing the pseudo ultrasound image calculated by the ultrasound image simulation unit in association with the patient 3D information;
An ultrasound transmitting and receiving unit that transmits ultrasound toward the patient's body and receives ultrasound returning from the patient's body;
An ultrasound image construction unit that constructs an actual ultrasound image from the ultrasound waves received by the ultrasound transmission / reception unit;
A respiratory state measurement unit that measures the respiratory state of the patient;
Based on the respiratory state measured by the respiratory state measuring unit, the actual ultrasonic image formed by the ultrasonic image forming unit is compared with the pseudo ultrasonic image stored in the database, An intracorporeal tissue position calculating unit for calculating a tissue position of the internal tissue position measuring device. In the internal tissue position measuring apparatus according to claim 1,
The tissue of the body is further provided with an input device for changing the position of the body tissue in the ultrasonic wave propagation model created by the ultrasonic wave propagation model creation unit and performing simulation based on the altered ultrasonic wave propagation model. Position measuring device. In the internal tissue position measuring apparatus according to claim 1,
The in-vivo tissue position calculation unit extracts the shape, size, and position of in-vivo tissue in each of the real ultrasound image and the pseudo-ultrasound image by image processing, and the difference in the shape, size, and position is A tissue position measuring device for body tissue, which is calculated as an error and the tissue position in the patient's body is calculated by comparing the calculated error with a preset threshold value. In the internal tissue position measuring apparatus according to claim 1,
The internal tissue position calculation unit calculates a correlation coefficient between the actual ultrasound image and the pseudo-ultrasound image, and compares the calculated correlation coefficient with a preset threshold value in the patient's body. An in-vivo tissue position measuring device characterized by calculating a tissue position. In the internal tissue position measuring apparatus according to claim 1,
The in-vivo tissue position measuring device is characterized in that the in-vivo tissue position calculation unit matches resolutions of the actual ultrasound image and the pseudo-ultrasound image by interpolating one of the pixel data. In the internal tissue position measuring apparatus according to claim 1,
The ultrasound system further comprises an ultrasonic reflector to be implanted in the patient's body,
The in-vivo tissue position measuring device is characterized in that the in-vivo tissue position calculating unit calculates the in-vivo tissue position in the patient's body by using the ultrasonic reflector reflected in the pseudo ultrasonic image and the actual ultrasonic image. What is claimed is: 1. A radiation therapy apparatus for identifying a target location of internal tissue and irradiating a target with radiation,
The internal tissue position measuring device according to claim 1;
An irradiation device for irradiating the target with the radiation;
A radiation treatment apparatus comprising: a radiation control unit configured to control a radiation irradiation position in the irradiation device based on an in-vivo tissue position measured using the in-vivo tissue position measuring device. An internal tissue position measuring method for determining internal tissue position in a patient's body by ultrasound.
Obtaining 3D information of the patient synchronized with the respiration;
Creating an ultrasonic wave propagation model using the acquired 3D information;
Simulating ultrasonic wave propagation in the created ultrasonic wave propagation model to create a pseudo-ultrasound image;
Storing the generated pseudo ultrasound image in a database in association with the patient 3D information;
Transmitting ultrasonic waves into the patient's body and receiving ultrasonic waves returning from the patient's body, and constructing a real ultrasonic image from the received ultrasonic waves;
Measuring the patient's respiratory status;
Calculating a tissue position in the body of the patient by comparing the actual ultrasound image and the pseudo-ultrasound image based on the measured respiratory state of the patient. Position measurement method. In the internal tissue position measuring method according to claim 8,
The step of calculating the position of body tissue is
Extracting, by image processing, the shape, size, and position of body tissue in each of the real ultrasound image and the pseudo ultrasound image by image processing;
Calculating the difference between the shape, size and position as an error;
And determining whether the actual ultrasound image and the pseudo ultrasound image coincide with each other by comparing the error with a preset threshold value. In the internal tissue position measuring method according to claim 8,
The step of calculating the position of body tissue is
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 coincide with each other by comparing the correlation coefficient with a preset threshold value. Method. In the internal tissue position measuring method according to claim 8,
The step of calculating the position of body tissue is
And b. Matching the resolutions of the actual ultrasound image and the pseudo-ultrasound image by interpolating any one of pixel data. In the internal tissue position measuring method according to claim 8,
The step of constructing the real ultrasound image comprises
Implanting an ultrasound reflector in the patient's body;
Calculating the position of the tissue in the patient's body using the ultrasound reflector as the index indicating the position of the body tissue to be measured, using the ultrasound reflector and the actual ultrasound image And a method of measuring the position of a tissue in the body.

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