JP2014136054A - Radiotherapy system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a treatment of a region to be treated accurately and precisely by correcting treatment plan information in consideration of an amount of deviation from a CT image incorporated in the treatment plan information, of an XVI image immediately before the treatment in a radiotherapy system.SOLUTION: A radiotherapy system includes: a bed 31 on which a subject to be examined is placed and which is configured so that a treatment region of the subject to be examined can be moved to a first imaging position and to a second imaging position; a radiotherapy device 50 for controlling a rotation part 55 and a diaphragm 58, and emitting radiation for the treatment; an imaging device for controlling an X-ray tube 51 for emitting an X-ray for imaging, and an X-ray detector 53 for detecting the X-ray from the X-ray tube 51, and imaging at the first imaging position; an X-ray CT device 20 for controlling an X-ray tube 21 for emitting an X-ray for imaging, and an X-ray detector 23 for detecting the X-ray from the X-ray tube 21, and imaging at the second imaging position; and control means for controlling the radiotherapy device 50 using the imaging device and the X-ray CT device 20.

Description

  Embodiments according to the present invention relate to a radiation therapy system capable of performing radiation therapy.

  In radiotherapy, image data is generated by imaging at the time of treatment planning, and treatment plan information is generated based on the image data.

  In the radiation therapy system, the position of the patient's body mark on the bed in the longitudinal direction (z-axis direction) is aligned with the z-axis position of the isocenter of the radiation therapy apparatus, and the vertical direction (y-axis direction) is the axis. The bed is rotated 180 degrees toward the imaging device. Then, the gantry of the imaging device is advanced in the z-axis direction toward the bed so that the isocenter of the imaging device coincides with the body surface mark of the patient on the bed.

  Subsequently, after imaging with the imaging apparatus, the bed is inverted 180 degrees toward the radiation therapy apparatus with the y-axis direction as an axis, and the patient is treated with the radiation therapy apparatus.

  As a technique related to the present embodiment, a radiation therapy system listed in the following Patent Document 1 is disclosed.

JP 2010-69086 A

  However, according to the prior art, in reality, the bed is sag (tilt of the bed) at the time of imaging by the imaging device. Therefore, when the depth from the body surface of the treatment site is calculated based on the image by imaging, the depth is calculated. An error occurs. Therefore, treatment of the treatment site cannot be performed accurately and accurately. Further, if an error occurs in the depth of the treatment site from the body surface, unnecessary exposure of the patient may be increased.

  In order to solve the above-described problem, the radiation therapy system according to the present embodiment is a bed on which a subject is placed and the treatment site of the subject can be moved between the first imaging position and the second imaging position. And a radiotherapy apparatus that irradiates therapeutic radiation by controlling a rotation mechanism and a diaphragm, a first X-ray source that irradiates imaging X-rays, and an X-ray from the first X-ray source A first imaging device that controls the first X-ray detector that detects the first imaging position to capture an image at the first imaging position, a second X-ray source that irradiates imaging X-rays, and the first A second imaging device that controls the second X-ray detector that detects X-rays from the two X-ray sources, and performs imaging at the second imaging position, the first imaging device, and the second imaging device. Control means for controlling the radiotherapy apparatus using the output of the imaging apparatus.

The external view which shows a part of radiotherapy system of this embodiment. The block diagram which shows the whole radiotherapy system of this embodiment. The block diagram which shows the function of the radiotherapy system of this embodiment. (A) is a diagram showing a bed and a slice position in the case of CT imaging in which sagging occurs, (B) includes a tumor corresponding to CT volume data at the time of treatment planning in the case of (A) The figure which shows CT image of a slice position. (A) is a diagram showing a bed and a slice position in the case of XVI in which droop does not occur, (B) is a slice position including a tumor corresponding to XVI volume data immediately before treatment in the case of (A) The figure which shows the XVI image of.

  The radiation therapy system of this embodiment is demonstrated with reference to an accompanying drawing.

  FIG. 1 is an external view showing a part of the radiation therapy system of the present embodiment. FIG. 2 is a configuration diagram showing the entire radiation therapy system of the present embodiment.

  FIG.1 and FIG.2 shows the radiotherapy system 1 of this embodiment. The radiation treatment system 1 includes a console 10, an imaging device 20, a bed device 30, a treatment planning device (not shown), and a radiation treatment device (linac: a radiation treatment device that performs treatment by irradiating radiation based on treatment plan information). 50. The imaging device 20 and the radiation therapy device 50 are disposed to face each other by 180 degrees with the bed device 30 interposed therebetween.

  The imaging device 20, the bed device 30, and the radiation therapy device 50 are usually installed in a treatment room as shown in FIG. On the other hand, the console 10 is usually installed in a control room adjacent to the treatment room. A treatment planning device (not shown) is installed outside the treatment room and the control room. Note that typical examples of the imaging apparatus 20 include an X-ray CT apparatus, an MRI (magnetic resonance imaging) apparatus, and an X-ray apparatus. Hereinafter, a case where an X-ray CT apparatus is used as the imaging apparatus 20 will be described.

  As shown in FIG. 2, the console 10 of the radiation therapy system 1 is configured based on a computer, and can communicate with a network such as a hospital backbone LAN (local area network) (not shown). The console 10 is mainly composed of basic hardware such as a CPU (central processing unit) 11, a main memory 12, an image memory 13, an HDD (hard disc drive) 14, an input device 15, and a display device 16. . The CPU 11 is interconnected to each hardware component constituting the console 10 via a bus as a common signal transmission path. Note that the console 10 may include a recording medium drive.

  The CPU 11 is a control device having a configuration of an integrated circuit (LSI) in which an electronic circuit made of a semiconductor is enclosed in a package having a plurality of terminals. When a command is input by operating the input device 15 by an operator such as a doctor, the CPU 11 executes a program stored in the main memory 12. Alternatively, the CPU 11 is a program stored in the HDD 14, a program transferred from the network and installed in the HDD 14, or a program read from a recording medium mounted on a recording medium drive (not shown) and installed in the HDD 14. Are loaded into the main memory 12 and executed.

  The main memory 12 is a storage device including a ROM (read only memory) and a RAM (random access memory). The main memory 12 stores IPL (initial program loading), BIOS (basic input / output system) and data, and is used for temporary storage of the work memory and data of the CPU 11.

  The image memory 13 is a storage device that stores image data included in treatment plan information, image data immediately before treatment, and the like.

  The HDD 14 is a storage device having a configuration in which a metal disk coated or vapor-deposited with a magnetic material is incorporated in a non-detachable manner. The HDD 14 is a storage device that stores a program (including an OS (operating system) in addition to an application program) installed in the console 10 and data. Also, it is possible to cause the OS to provide a graphical user interface (GUI) capable of performing basic operations by the input device 15 by using graphics frequently for displaying information on the display device 16 for an operator such as an operator. it can.

  The input device 15 is a pointing device that can be operated by an operator, and an input signal according to the operation is sent to the CPU 11.

  The display device 16 includes an image composition circuit (not shown), a video random access memory (VRAM), a display, and the like. The image synthesizing circuit generates synthesized data obtained by synthesizing character data of various parameters with image data. The VRAM develops the composite data as display image data to be displayed on the display. The display is configured by a liquid crystal display, a cathode ray tube (CRT), or the like, and sequentially displays display image data as a display image.

  The console 10 controls operations of the X-ray CT apparatus 20, the bed apparatus 30, and the radiation therapy apparatus 50. Further, the console 10 generates projection data by performing logarithmic conversion processing and correction processing (preprocessing) such as sensitivity correction on the raw data input from the DAS 24 of the X-ray CT apparatus 20, and generates projection data based on the projection data. In addition, slice data as two-dimensional image data and volume data as three-dimensional image data are generated.

  The X-ray CT apparatus 20 of the radiotherapy system 1 images a region including a treatment site in order to display image data of the region including a treatment site such as cancer or tumor of the patient (subject) O. The X-ray CT apparatus 20 includes an X-ray tube 21 as a radiation source, a diaphragm 22, an X-ray detector 23, a DAS (data acquisition system) 24, a rotating unit 25, a high voltage supply device 26, and an imaging controller 29. The X-ray tube 21, the diaphragm 22, the X-ray detector 23, the DAS 24, the rotating unit 25, and the high voltage supply device 26 are provided inside a gantry G. On the other hand, the imaging controller 29 is provided outside the gantry G. The gantry G can move forward and backward in the z-axis direction (longitudinal direction of the couch device 30) via the wheels L with respect to the couch device 30 on which the patient O is placed. The X-ray CT apparatus 20 has a configuration capable of generating an image with relatively good at least one of noise, contrast resolution, and resolution from an imaging system (XVI) of the radiation therapy apparatus 50 described later.

  The X-ray tube 21 generates a braking X-ray by causing an electron beam to collide with a metal target according to the tube voltage supplied from the high voltage supply device 26, and the X-ray is directed toward the X-ray detector 23. Irradiate. Cone beam X-rays are formed by X-rays emitted from the X-ray tube 21.

  The diaphragm 22 adjusts the irradiation range of the X-rays emitted from the X-ray tube 21 under the control of the imaging controller 29. That is, the X-ray irradiation range can be changed by adjusting the aperture of the diaphragm 22 under the control of the imaging controller 29.

  The X-ray detector 23 is a matrix, that is, a two-dimensional array type X-ray detector 23 having a plurality of channels in the channel direction and a plurality of rows in the slice direction (also referred to as a multi-slice detector). It is. The X-ray detection element of the X-ray detector 23 detects X-rays emitted from the X-ray tube 21.

  The DAS 24 amplifies the transmission data signal detected by each X-ray detection element of the X-ray detector 23 and converts it into a digital signal. Output data from the DAS 24 is supplied to the console 10 via the imaging controller 29.

  The rotating unit 25 integrally holds the X-ray tube 21, the diaphragm 22, the X-ray detector 23, and the DAS 24. The rotating unit 25 rotates around the patient O in a state where the X-ray tube 21 and the X-ray detector 23 are opposed to each other by the control of the imaging controller 29. The direction parallel to the rotation center axis of the rotating unit 25 is the z-axis direction (longitudinal direction of the bed 31), the plane orthogonal to the z-axis direction is the x-axis direction (left-right direction of the bed 31), and the y-axis direction (vertical) Direction).

  The high voltage supply device 26 supplies power necessary for X-ray irradiation to the X-ray tube 21 under the control of the imaging controller 29.

  The imaging controller 29 includes a CPU and a memory. The imaging controller 29 controls the X-ray tube 21, the X-ray detector 23, the DAS 24, the high voltage supply device 26, and the like to execute a scan with the operation of the bed apparatus 30.

  The bed apparatus 30 of the radiation therapy system 1 includes a bed 31, a bed driving device 32, and a bed controller 39.

  The bed 31 is a six-axis (x axis, y axis, z axis, roll, pitch, yaw) variable bed on which the patient O can be placed. The bed 31 is configured to be able to move the treatment site of the patient O to both the imaging position on the X-ray tube 21 side and the imaging position on the X-ray tube 51 side.

  The bed driving device 32 is controlled by the bed controller 39 to slide the bed 31 along the x-axis direction, the y-axis direction, and the z-axis direction, and the bed 31 in the x-axis direction, y-axis direction, and z-axis direction. And a mechanism for rotating and reversing the bed 31 180 degrees about the y-axis direction.

  The bed controller 39 includes a CPU and a memory. The couch controller 39 controls the couch driving device 32 and the like, thereby executing a scan with the operation of the X-ray CT apparatus 20. The couch controller 39 controls the couch driving device 32 and the like, thereby executing radiotherapy with the operation of the radiotherapy device 50.

  The radiotherapy apparatus 50 of the radiotherapy system 1 can generally generate MV class radiation. The radiation therapy apparatus 50 installs a diaphragm (collimator) at a radiation generation port, and realizes an irradiation shape and a dose distribution based on the treatment plan by the diaphragm. In recent years, a multi-leaf collimator (MLC) that can form a dose distribution corresponding to a complicated tumor shape by a plurality of movable leaves as a diaphragm is often used. The radiation therapy apparatus 50 adjusts the radiation dose by the irradiation field formed by the diaphragm, and eliminates or reduces the treatment site of the patient O. The combination of the X-ray CT apparatus 20, the bed apparatus 30, and the radiation therapy apparatus 50 is called “linac-CT”.

  The radiotherapy apparatus 50 is equipped with an imaging apparatus (XVI: X-ray volume imaging) that is coaxial with a therapeutic radiation isocenter (hereinafter referred to as “treatment isocenter”) and performs CT imaging using cone beam technology. The radiotherapy apparatus 50 includes an X-ray tube 51, an aperture 52, an X-ray detector 53, an AD (analog to digital) converter 54, a rotating unit 55, a high voltage supply device 56, a radiation source 57, an aperture 58, and a treatment controller. 59.

  The X-ray tube 51 generates a braking X-ray by causing an electron beam to collide with a metal target according to the tube voltage supplied from the high voltage supply device 56, and the X-ray is directed toward the X-ray detector 53. Irradiate. Cone beam X-rays are formed by X-rays emitted from the X-ray tube 51.

  The diaphragm 52 adjusts the irradiation range of the X-rays irradiated from the X-ray tube 51 under the control of the treatment controller 59. That is, the X-ray irradiation range can be changed by adjusting the aperture of the diaphragm 52 under the control of the treatment controller 59.

  The X-ray detector 53 is an FPD (Flat Panel Detector) having a plurality of X-ray detection elements arranged in two dimensions. The X-ray detection element of the X-ray detector 53 detects X-rays emitted from the X-ray tube 51.

  The AD converter 54 converts the projection data of the time-series analog signal (video signal) output from the FPD 221 into a digital signal. Output data of the AD converter 54 is supplied to the console 10 via the treatment controller 59.

  The rotating unit 55 integrally holds the X-ray tube 51, the diaphragm 52, the X-ray detector 53, the AD converter 54, the radiation source 57, and the diaphragm 58. The rotating unit 55 rotates around the patient O with the X-ray tube 51 and the X-ray detector 53 facing each other. The direction parallel to the rotation center axis of the rotating unit 55 is the z-axis direction (longitudinal direction of the bed 31), the plane orthogonal to the z-axis direction is the x-axis direction (left-right direction of the bed 31), and the y-axis direction (vertical) Direction).

  The high voltage supply device 56 supplies power necessary for radiation irradiation to the X-ray tube 51 and the radiation source 57 under the control of the treatment controller 59.

  The radiation source 57 generates radiation according to the tube voltage supplied from the high voltage supply device 56.

  The diaphragm 58 adjusts the irradiation range of the radiation emitted from the radiation source 57 under the control of the treatment controller 59. That is, by adjusting the opening of the diaphragm 58 under the control of the treatment controller 59, the radiation irradiation range can be changed.

  The treatment controller 59 includes a CPU and a memory. The treatment controller 59 includes an X-ray tube 51, an X-ray detector 53, an AD converter 54, a high level according to treatment plan information (or corrected treatment plan information described later) generated by a treatment plan apparatus (not shown). By controlling the voltage supply device 56, the radiation source 57, and the like, X-ray irradiation for XVI and radiation for treatment are executed with the operation of the bed apparatus 30.

  FIG. 3 is a block diagram showing functions of the radiation therapy system 1 of the present embodiment.

  When the CPU 11 of the console 10 executes the program, the radiotherapy system 1 includes an XVI execution unit 71, a bed position recording unit 72, a CT imaging execution unit 73, a deviation amount calculation unit 74, and a treatment as shown in FIG. It functions as the execution means 75. In addition, although the means 71-75 is demonstrated as what functions as software in the radiation therapy system 1, all or one part of the means 71-75 may be equipped with the radiation therapy system 1 as hardware. Good.

  The XVI execution means 71 controls the operation of the bed controller 39 of the bed apparatus 30 after the patient is placed on the bed 31 immediately after the treatment plan, for example, immediately before the treatment. Has a function of moving the bed 31 so as to coincide with the isocenter of the radiation therapy apparatus 50 irradiated with reference light (laser light) from a projector (not shown) attached to the wall or ceiling of the treatment room. The XVI execution means 71 has a function of controlling the operation of the treatment controller 59 of the radiation therapy apparatus 50 to execute XVI of the patient O on the bed 31.

  Note that the XVI execution means 71 performs processing such as image reconstruction processing on the transmission data acquired by the radiation therapy apparatus 50 to generate XVI volume data V1 immediately before treatment. The XVI volume data V1 immediately before treatment generated by the XVI execution means 71 is stored in a storage device such as the image memory 13.

  The bed position recording unit 72 has a function of recording the positions of the six axes of the bed 31 in the XVI of the XVI execution unit 71 in a storage device such as the HDD 14.

  The CT imaging execution means 73 has a function of controlling the operation of the bed controller 39 of the bed apparatus 30 while maintaining the patient O on the bed 31 and rotating the bed 31 180 degrees about the y-axis direction. Further, the CT imaging execution means 73 controls the operation of the imaging controller 29 of the X-ray CT apparatus 20 while maintaining the patient O on the bed 31 to advance the gantry G toward the radiotherapy apparatus 50, and at a predetermined position. It has a function to stop at.

  The CT imaging execution means 73 has a function of controlling the operation of the imaging controller 29 of the X-ray CT apparatus 20 and executing CT imaging of a region including the treatment site of the patient O.

  Note that the CT volume data V2 immediately before treatment is generated by performing processing such as image reconstruction processing on the transmission data acquired by the X-ray CT apparatus 20 by the CT imaging execution means 73. The CT volume data V2 immediately before treatment generated by the CT imaging execution means 73 is stored in a storage device such as the image memory 13.

  When the CT volume data V0 at the time of treatment planning included in the treatment plan information and acquired by the X-ray CT apparatus 20 is compared with the CT volume data V2 immediately before treatment acquired by the X-ray CT apparatus 20 just before the treatment, It is possible to detect changes in the tumor (position shift, size change, etc.) from the time of treatment planning to just before treatment. Further, based on the CT volume data V0 at the time of treatment planning and the XVI volume data V1 immediately before the treatment, it is possible to detect the amount of image shift due to the sag of the bed 31 (bed tilt).

  The deviation amount calculating means 74 is the CT volume data V0 (XVI volume data V1 immediately before the treatment stored in the image memory 13 (the XVI image constituting the XVI volume data V1) stored in the image memory 13 at the time of the treatment plan. It has a function of calculating the amount of deviation from the CT image constituting the CT volume data V0 as being caused by the sagging of the bed 31 or the like.

  FIG. 4A is a diagram illustrating the bed 31 and the slice position in the case of CT imaging in which sagging occurs. FIG. 4B is a diagram showing a CT image of a slice position including a tumor corresponding to the CT volume data V0 at the time of treatment planning in the case shown in FIG. FIG. 5A is a diagram illustrating the bed 31 and the slice position in the case of XVI imaging in which no sagging occurs. FIG. 5B is a diagram illustrating an XVI image of a slice position including a tumor corresponding to the XVI volume data V1 immediately before treatment in the case illustrated in FIG.

  When CT imaging is performed with the X-ray CT apparatus 20 at the time of treatment planning (same as before treatment), sagging θ may occur in the bed 31 as shown in FIG. As shown in FIG. 4A, when the sagging θ occurs in the bed 31, the slice position S0 including the tumor T is shown in FIG. 4B based on the CT volume data V0 at the time of treatment planning. A CT image is obtained.

  On the other hand, when XVI is performed immediately before treatment by the radiation therapy apparatus 50, as shown in FIG. As shown in FIG. 5A, when the bed 31 does not sag, an XVI image of the slice position S1 including the tumor T is obtained as shown in FIG.

  In the case of a CT image in which sagging θ occurs on the bed 31 as shown in FIG. 4A, a tumor T exists at a position at a depth D0 from the body surface based on the CT image shown in FIG. However, in the case of an XVI image in which the bed 31 does not sag as shown in FIG. 5A, based on the XVI image shown in FIG. 5B, the body surface is positioned at a depth D1 (D1 <D0). Tumor T is present. Therefore, when treating the tumor T with the radiation therapy apparatus 50, if an attempt is made to perform radiation therapy based on the depth D0 of the tumor T based on the CT image included in the treatment plan information, an error with respect to the depth D1 at the time of treatment is present. Will exist. Therefore, a deviation amount of the XVI volume data V1 immediately before treatment from the CT volume data V0 at the time of treatment planning is calculated.

  Returning to the explanation of FIG. 3, the treatment execution means 75 controls the operation of the imaging controller 29 of the X-ray CT apparatus 20 while maintaining the patient O on the bed 31, and makes the gantry G opposite to the radiation therapy apparatus 50. It has the function of retracting to the side and stopping at the home position. Further, the treatment execution means 75 controls the operation of the bed controller 39 of the bed apparatus 30 while maintaining the patient O on the bed 31 and rotates (reverses) the bed 31 180 degrees about the y-axis direction. Have Further, when applying the treatment plan information to the radiation therapy apparatus 50, the treatment execution means 75 corrects the treatment plan information based on the deviation amount between the volume data calculated by the deviation amount calculation means 74, and is corrected. According to the treatment plan information, the operation of the treatment controller 59 of the radiotherapy apparatus 50 is controlled to perform the treatment of the treatment site of the patient O.

  The treatment execution means 75 corrects the treatment plan information by aligning the CT volume data V0 at the time of treatment planning with the XVI volume data V1 immediately before the treatment based on the deviation amount calculated by the deviation amount calculation means 74. . Further, the treatment execution means 75 controls the opening degree of the aperture 58 (shown in FIG. 2) using the irradiation information of the therapeutic radiation included in the treatment plan information and the deviation amount calculated by the deviation amount calculation means 74. May be. The treatment execution means 75 may adjust the position of the bed 31 at the time of treatment according to the deviation amount calculated by the deviation amount calculation means 74.

  According to the radiation therapy system 1 of the present embodiment, the CT image included in the treatment plan information and the CT image immediately before the treatment are provided by including the imaging system on the X-ray CT apparatus 20 side and the imaging system on the radiation therapy apparatus 50 side. Since the treatment plan information can be corrected by comparing the CT image included in the treatment plan information with the XVI image immediately before the treatment, the treatment site can be treated accurately and accurately.

  Further, according to the radiation treatment system 1 of the present embodiment, the treatment plan information can be corrected in consideration of the deviation amount of the XVI image immediately before the treatment from the CT image included in the treatment plan information, so that the treatment of the treatment site can be accurately performed. Can be carried out with high accuracy. In addition, according to the radiation treatment system 1 of the present embodiment, the treatment plan information can be corrected in consideration of the deviation amount of the XVI image immediately before the treatment from the CT image included in the treatment plan information. Can be reduced.

  Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1 Radiotherapy system 10 Console 20 Imaging device (X-ray CT device)
30 bed apparatus 31 bed 50 radiation therapy apparatus 51 X-ray tube 53 X-ray detector 71 XVI execution means 72 bed position recording means 73 CT imaging execution means 74 deviation amount calculation means 75 treatment execution means

Claims (5)

A bed placed on the subject and configured to move the treatment site of the subject to the first imaging position and the second imaging position;
A radiotherapy device that controls the rotation mechanism and the diaphragm to irradiate therapeutic radiation; and
A first X-ray source that irradiates imaging X-rays and a first X-ray detector that detects X-rays from the first X-ray source are controlled at the first imaging position. A first imaging device for imaging;
A second X-ray source that emits X-rays for imaging and a second X-ray detector that detects X-rays from the second X-ray source are controlled at the second imaging position. A second imaging device for imaging;
Control means for controlling the radiation therapy apparatus using outputs of the first imaging apparatus and the second imaging apparatus;
A radiation therapy system. The control means includes
Means for obtaining a shift amount between the first image captured by the first imaging device and the second image captured by the second imaging device;
Means for aligning the image included in the treatment plan information with the second image captured by the second imaging device based on the shift amount;
The radiation therapy system according to claim 1, comprising:   The radiotherapy system according to claim 2, wherein the control unit controls the aperture of the diaphragm using irradiation information of therapeutic radiation included in the treatment plan information and the deviation amount.   The radiotherapy system according to claim 2 or 3, wherein the shift amount represents an inclination of the bed.   5. The second imaging device according to claim 1, wherein the second imaging device has a configuration capable of generating an image having at least one of noise, contrast resolution, and resolution that is relatively better than that of the first imaging device. 6. Radiation therapy system.

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