JP2014151007A - Radiotherapy system, radiotherapy apparatus, and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To designate a radiation irradiating condition, which is employed in radiotherapy, in consideration of a dose for imaging to be performed to acquire image data.SOLUTION: A radiotherapy apparatus 110 that performs radiotherapy on a therapeutic object region of a patient includes an image/imaging condition acquisition unit 5 that acquires image data of the patient which is fed from a separately provided image acquisition device prior to the radiotherapy and an imaging condition for acquisition of the image data, a dose calculation unit 8 that calculates a therapeutic dose, which is preferable to the radiotherapy, on the basis of the imaging condition, and a radiation control unit 31 that designates a radiation irradiating condition, which is employed in the radiotherapy, on the basis of a result of calculation of the therapeutic dose.

Description

  Embodiments described herein relate generally to a radiation therapy system, a radiation therapy apparatus, and a control program for treating a lesion of a patient by irradiating radiation.

  In recent years, a treatment method called “minimally invasive treatment” has attracted attention, and in the field of malignant tumor treatment, active attempts have been made for minimally invasive treatment. Especially in the case of malignant tumors, many of the treatments have been relied on surgical operations. However, in the case of conventional surgical treatments, that is, when performing extensive tissue excision, the original function and appearance of the organs In many cases, the form is greatly impaired, and even if it is alive, a great burden is placed on the patient. For such conventional surgical treatment, a minimally invasive treatment method considering quality-of-life (QOL) is strongly desired. As one of the methods, radiation is applied to a lesion such as a tumor tissue. So-called radiation therapy is performed.

  In addition, recently, the position and shape of a lesion are accurately measured using a medical image diagnostic apparatus such as an X-ray CT apparatus, and the irradiation position, irradiation area, irradiation direction, and treatment used based on the measurement results are measured. Since radiotherapy for the lesion is performed by the radiotherapy apparatus according to the treatment plan including the radiation dose, damage to normal tissues and side effects are remarkably reduced.

  Furthermore, a positional shift between the image data collected for the purpose of radiotherapy treatment planning and the image data collected immediately before the radiotherapy is detected, and the position of the patient at the time of the radiotherapy is determined based on this positional shift detection result. There has also been proposed a radiotherapy apparatus capable of performing accurate radiotherapy on a lesion by correction.

  In such a radiotherapy apparatus, a radiation restrictor for limiting the radiation irradiation region to the lesion or the vicinity thereof is provided between the radiation generator and the patient, and is provided in the multi-part diaphragm of the radiation restrictor. By arbitrarily moving each of the plurality of aperture blocks, it is possible to set an optimal radiation irradiation region even for a lesion portion having an irregular shape.

JP 2012-35072 A

  After correcting the patient's position in radiation therapy based on the treatment plan image data collected at the time of treatment planning and the position shift detection image data collected immediately before the radiation treatment, the radiation treatment is performed based on the treatment plan prepared in advance. By doing so, it is possible to irradiate therapeutic radiation to the exact position of the lesion.

  However, when the above-mentioned conventional radiotherapy apparatus is used to irradiate the lesion with therapeutic radiation having a strength suitable for the radiotherapy that has been set in advance, it is used for detecting a positional deviation performed prior to the radiotherapy. Irradiation intensity and duration of treatment radiation (hereinafter collectively referred to as irradiation conditions) were set without considering the radiation dose for imaging in the collection of image data. The radiation dose applied to the patient exceeds the therapeutic radiation dose set at the time of treatment planning (hereinafter referred to as the planned treatment radiation dose), and therefore there is a problem that it is difficult to perform safe radiation treatment for the patient. It was.

  The present disclosure has been made in view of the above-described problems, and an object of the present disclosure is to irradiate a lesion of a patient (hereinafter, referred to as a treatment target site) with radiation having a predetermined intensity. Radiation that enables safe and effective radiotherapy by controlling the radiation dose for radiotherapy in consideration of imaging conditions at the time of image data collection for positional deviation detection preceding radiotherapy when performing therapy To provide a treatment system, a radiotherapy apparatus, and a control program.

  In order to solve the above problems, a radiotherapy apparatus of the present disclosure is a radiotherapy apparatus that performs radiotherapy on a treatment target site of a patient, and precedes the radiotherapy from a separately installed image acquisition apparatus. Image data / imaging condition acquisition means for acquiring image data of the patient to be supplied and imaging conditions at the time of collection of the image data, and radiation dose for calculating a therapeutic radiation dose suitable for the radiotherapy based on the imaging conditions It is characterized by comprising calculation means and radiation control means for setting radiation irradiation conditions in the radiation therapy based on the calculation result of the therapeutic radiation dose.

The figure which shows schematic structure of the radiotherapy system in embodiment of this indication. The block diagram which shows the whole structure of the radiotherapy apparatus with which the radiotherapy system of this embodiment is provided. The figure which shows the specific structure of the radiation restrictor with which the radiotherapy apparatus of this embodiment is provided. The figure for demonstrating the aperture block with which the radiation aperture device of this embodiment is provided. The figure for demonstrating the function of the position shift detection part with which the radiotherapy apparatus of this embodiment is provided. The block diagram which shows the whole structure of the image acquisition device with which the radiotherapy system of this embodiment is provided. 6 is a flowchart showing an image data collection procedure by the image collection apparatus of the present embodiment. The flowchart which shows the formulation procedure of the treatment plan in this embodiment. The flowchart which shows the procedure of the radiotherapy in this embodiment.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

(Embodiment)
The radiotherapy apparatus with which the radiotherapy system of this embodiment is provided, when performing radiotherapy on a treatment target site of a patient, a patient in a treatment plan performed prior to the radiotherapy and the position of the patient immediately before the radiotherapy Based on the imaging conditions at the time of acquisition of misalignment detection image data for the purpose of misalignment detection, the radiation dose for imaging at the time of acquisition of misalignment detection image data was estimated, and this radiation dose for imaging was calculated. Radiotherapy is performed on the treatment target site according to the therapeutic radiation dose.

  In the following embodiment, a case where an X-ray CT apparatus is used as an image acquisition apparatus constituting the radiotherapy system will be described. However, the image acquisition apparatus may be an X-ray diagnostic apparatus or other imaging. It may be a medical image diagnostic apparatus capable of imaging with radiation for medical use.

(System configuration and functions)
The configuration and function of the radiation therapy system in the present embodiment will be described with reference to FIGS. FIG. 1 is a diagram for explaining a schematic configuration of the radiation therapy system, and FIGS. 2 and 6 are block diagrams showing the overall configuration of the radiation therapy apparatus and the image acquisition apparatus provided in the radiation therapy system. . FIGS. 3, 4 and 5 are diagrams for explaining the radiation restrictor and the positional deviation detection unit provided in the above-described radiotherapy apparatus.

  As shown in FIG. 1, the radiation treatment system 100 of the present embodiment aims at a radiation treatment apparatus 110 that irradiates therapeutic radiation to a treatment target region of a patient 150 and a treatment plan performed prior to the radiation treatment. Image collection apparatus for collecting positional deviation detection image data for the purpose of detection of positional deviation between the treatment plan image data and the patient 150 in the treatment plan and the patient 150 in radiation therapy performed at a different time from the treatment plan 120 and a bed 130 for moving a treatment target part of a patient 150 placed on the top board 131 to a radiation irradiation region of the radiation therapy apparatus 110 and an imaging field of the image collection apparatus 120.

  The radiotherapy apparatus 110 includes a fixed gantry 1x that is fixed and installed on the floor, a rotating gantry 2x that is connected to the side surface of the fixed gantry 1x and that is rotatably held at the connecting portion, and the rotating gantry 2x. The radiation generator 32 provided at the distal end of the L-shaped arm 2a provided to irradiate the treatment target site of the patient 150 with therapeutic radiation, and the treatment target site of the patient 150 provided near the radiation generator 32 And a radiation restrictor 33 for setting a radiation irradiation region of a predetermined size.

  Next, the radiotherapy apparatus 110 constituting the radiotherapy system 100 will be described with reference to FIG.

  FIG. 2 is a block diagram showing an overall configuration of the radiation therapy apparatus 110. As shown in FIG. 2, the radiation therapy apparatus 110 is predetermined with respect to a treatment target site of a patient 150 placed on a top board 131. The radiation generating unit 3 for irradiating intense therapeutic radiation, the radiation restrictor 33 provided in the radiation generating unit 3, the moving mechanism unit 4 for moving the above-described top plate 131 to a desired position, and the image collecting device 120 are not shown. Image data / imaging condition acquisition unit 5 for acquiring treatment plan image data and position deviation detection image data supplied via a network, a storage medium, etc., and imaging conditions at the time of collection of these image data, and image / imaging conditions The imaging condition data at the time of collecting each image data is added to the image data for treatment plan and the image data for position shift detection supplied from the acquisition unit 5 and stored. A data storage unit 6 for storing the treatment plan or the like of the radiotherapy was formulated on the basis of the image data, and a display unit 7 for displaying the above-described treatment planning image data and positional deviation detection image data.

  Further, the radiotherapy apparatus 110 is suitable for the radiotherapy based on the imaging conditions at the time of collecting the positional deviation detection image data read from the data storage unit 6 (that is, enables safe and effective radiotherapy). A treatment plan for the patient 150 placed on the top board 131 by comparing the radiation dose calculation unit 8 for calculating the treatment radiation dose and the treatment plan image data read from the data storage unit 6 and the positional deviation detection image data. Position shift detection unit 9 for detecting a difference (position shift) between the position at the time of radiation and the position at the time of radiotherapy, input of patient information, formulation of a treatment plan based on image data for treatment plan, input of various instruction signals, etc. And a system control unit 11 for controlling the above-mentioned units in an integrated manner.

  Next, the configuration and functions of the unit included in the radiation therapy apparatus 110 will be described in more detail.

  The radiation generation unit 3 of the radiation therapy apparatus 110 illustrated in FIG. 2 includes a radiation control unit 31 that controls therapeutic radiation for the patient 150 based on the calculation result of the therapeutic radiation dose supplied from the radiation dose calculation unit 8; A radiation generator 32 for generating therapeutic radiation having an intensity suitable for radiation therapy based on a control signal supplied from the radiation control unit 31 and a radiation restrictor 33 for setting a radiation irradiation region for the patient 150 are provided. Yes.

  The radiation control unit 31 determines the radiation dose for imaging suitable for the radiotherapy obtained from the radiation dose calculation unit 8 via the system control unit 11 (that is, the imaging radiation dose at the time of collecting the positional deviation detection image data). Based on the therapeutic radiation dose calculated by the radiation dose calculation unit 8 in consideration, the radiation voltage is emitted from the radiation generator 32 by controlling the application voltage, the application time, and the like in the high voltage generator of the radiation generator 32 described later. Set the irradiation conditions (irradiation intensity, irradiation time, etc.) for therapeutic radiation.

  The radiation generator 32 includes a high voltage generator (not shown) and an X-ray tube. The high voltage generator applies a high voltage between the anode and the cathode to accelerate the thermoelectrons generated from the cathode of the X-ray tube, and the X-ray tube is supplied with the high voltage supplied from the high voltage generator. Electrons accelerated by the voltage are made to collide with the tungsten target to emit therapeutic radiation suitable for the radiotherapy.

  On the other hand, as shown in FIG. 3, the radiation restrictor 33 includes diaphragms 331a and 331b for setting the irradiation range of the therapeutic radiation in the first direction (z direction in FIG. 3A), and first orthogonal to this. 2 has multi-divided diaphragms 332a and 332b for setting an irradiation range of therapeutic radiation in two directions (x direction in FIG. 3B), and each of the multi-divided diaphragm bodies 332a and 332b includes a plurality (N pieces). ) Aperture block. Then, by moving the diaphragm blocks of the diaphragm body 331a and the diaphragm body 331b and the multi-division diaphragm body 332a and the multi-division diaphragm body 332b to a desired position by using a diaphragm movement mechanism 41 described later provided in the movement mechanism unit 4, the patient A radiation irradiation region Ro having a shape corresponding to 150 treatment target parts is formed.

  In other words, the above-described diaphragm bodies 331a and 331b include the z-direction diaphragm movement mechanisms 411a and 411b, and the diaphragm blocks 332a-1 to 332a-N and the multi-segment diaphragm body 332b included in the multi-segment diaphragm body 332a. The blocks 332b-1 to 332b-N are connected to the x-direction diaphragm moving mechanisms 412a-1 to 412a-N and the diaphragm moving mechanisms 412b-1 to 412b-N.

  FIG. 4 shows diaphragm blocks 332a-1 to 332a-N provided in the multi-divided diaphragm body 332a, diaphragm movement mechanisms 412a-1 to 412a-N that move these diaphragm blocks in the x direction, and the multi-divided diaphragm body. The aperture blocks 332b-1 to 332b-N provided in the aperture 332b and aperture movement mechanisms 412b-1 to 412b-N for moving these aperture blocks in the x direction are shown, and the aperture blocks 332a-1 to 332a-N and By moving the aperture blocks 332b-1 to 332b-N independently in the x direction, the radiation irradiation region Ro having an arbitrary shape can be set.

  Returning to FIG. 2, the moving mechanism unit 4 includes a diaphragm moving mechanism 41, a top plate moving mechanism 42, and a mechanism control unit 43 that controls these moving mechanisms.

  The mechanism control unit 43 receives the positional deviation detection result between the treatment planning image data and the positional deviation detection image data supplied from the positional deviation detection unit 9 via the system control unit 11 and detects the obtained positional deviation. By supplying the top-plate movement control signal generated based on the result to the top-plate movement mechanism 42, the patient 150 immediately before the radiation treatment placed on the top plate 131 is moved to the same position as at the time of treatment planning.

  Further, the mechanism control unit 43 receives the treatment plan supplied from the data storage unit 6 via the system control unit 11, and based on the region information of the radiation irradiation region included in the treatment plan, the diaphragm movement control signal Is generated. Then, the obtained diaphragm movement control signal is supplied to the diaphragm movement mechanism 41 to move the multi-part diaphragms 332a and 332b of the radiation diaphragm 33 connected to the diaphragm movement mechanism 41 to a predetermined position. A radiation irradiation region is set for the treatment target region of the patient 150 arranged at the same position as the time.

  Next, the image / imaging condition acquisition unit 5 is connected to, for example, an image / imaging condition output unit 29 described later included in the image collection device 120 via a network or the like (not shown). The collected image data for treatment planning, the position deviation detection image data collected immediately before the radiation treatment for the purpose of detecting the position deviation of the patient 150 at the time of treatment planning and at the time of radiation treatment, and further, Get shooting conditions at the time of collection. In this case, each of the treatment plan image data and the positional deviation detection image data is supplied from the image collection device 120 using the above-described imaging conditions as supplementary information.

  The data storage unit 6 includes an image data storage unit and a treatment plan storage unit (not shown). The image data storage unit collects the image data by the image collection device 120 and supplies the treatment data for the treatment plan acquired through the image / imaging condition acquisition unit 5. The image data and image data for position shift detection are stored as incidental information on the shooting conditions at the time of collecting the respective image data.

  On the other hand, in the treatment plan storage unit, based on the treatment plan image data displayed on the display unit 7, a medical worker in charge of the radiation treatment (hereinafter referred to as an operator) uses the input device of the input unit 10. The treatment plan suitable for the radiotherapy formulated by using the data is stored. In this case, the treatment plan storage unit described above is based on the irradiation direction and irradiation region for the patient 150 set at the time of formulation of the treatment plan, and further based on the age, sex, weight, medical history, treatment target, etc. of the patient 150. The planned treatment radiation dose for the irradiation region is stored in advance as the above-mentioned treatment plan.

  Next, the display unit 7 in FIG. 2 displays the display data obtained by converting the image data collected by the image collecting device 120 into a predetermined display format and generating display data. Monitors (both not shown). When the treatment plan is formulated, the treatment plan image data supplied from the image collection device 120 via the image / imaging condition acquisition unit 5 and the system control unit 11 is displayed on its own monitor. At this time, based on the treatment plan image data displayed on the display unit 7, the operator uses the input device of the input unit 10 to formulate a treatment plan effective for the radiation treatment including setting of the radiation irradiation region.

  Further, when the image data for position shift detection collected by the image acquisition device 120 immediately before the radiotherapy is supplied via the image / imaging condition acquisition unit 5, the image data for position shift detection and the image of the data storage unit 6 are provided. The treatment plan image data read from the data storage unit is displayed on the display unit 7. At this time, the operator compares and observes the treatment plan image data and the positional deviation detection image data displayed on the display unit 7, so that the treatment time and radiation treatment time of the patient 150 placed on the tabletop 131 are measured. It is checked if necessary whether or not the positions at are coincident.

  On the other hand, the radiation dose calculation unit 8 reads out the imaging conditions at the time of collecting the image data stored together with the positional deviation detection image data in the image data storage unit of the data storage unit 6 and is included in the imaging conditions. The X-ray dose Da (Gy) used at the time of collecting the image data for position shift detection is estimated based on the applied voltage and the application time of the high voltage generator. Then, the obtained X-ray dose Da (Gy) is converted into an imaging radiation dose Ga (MU) having the same unit as the therapeutic radiation dose of radiotherapy.

  Next, the radiation dose calculation unit 8 is set based on the age, sex, weight, medical history, treatment target, etc. of the patient 150 at the time of formulation of the treatment plan, and the planned treatment stored in the treatment plan storage unit of the data storage unit 6 The radiation dose Go (MU) for reading is read out. Then, by substituting the obtained radiation dose Ga (MU) for the planned treatment at the time of collection of the obtained planned treatment radiation dose Go (MU) and the positional deviation detection image data into the following equation (1), the radiotherapy A therapeutic radiation dose Gx (MU) suitable for the above is calculated. However, the radiation dose Go (MU) for planned treatment described above may be arbitrarily set by the operator at the time of treatment planning.

The above (Gy) is a unit of X-ray dose irradiated to the patient 150 at the time of image data collection, and (MU) represents a unit of therapeutic radiation dose irradiated to the patient 150 in radiotherapy. ing.

  Next, the positional deviation detection unit 9 collects treatment plan image data collected at the time of treatment planning in order to match the position at the time of treatment planning of the patient 150 placed on the top board 131 with the position at the time of radiation treatment. And a function of detecting a positional deviation between the positional deviation detection image data collected immediately before the radiotherapy.

  Various methods have already been proposed as a method for detecting misalignment between image data. Hereinafter, misalignment detection using the pattern matching method will be described.

  That is, the positional deviation detection unit 9 of the present embodiment includes an arithmetic processing unit (not shown), and sets a region of interest of a predetermined size for the treatment plan image data read from the image data storage unit of the data storage unit 6. Then, the positional deviation detection image for the therapeutic planning image data is obtained by correlation processing between the pixel of the therapeutic planning image data extracted from the region of interest and the pixel of the positional deviation detection image data read from the image data storage unit. The positional deviation of data (that is, the difference between the position of the patient 150 placed on the top board 131 at the time of treatment planning and the position immediately before radiation treatment) is detected.

  Next, a specific example of the positional deviation detection method to which the correlation process is applied will be described with reference to FIG. However, here, the positional deviation detection for the three-dimensional treatment planning image data and the positional deviation detection image data collected by the image collecting device 120 will be described. However, the two-dimensional treatment planning image data and the positional deviation detection image are described. It is also possible to detect positional deviation with respect to data.

In FIG. 5, the pixel (voxel) of the image data Vo for position shift detection is represented by A (f, g, h) (f = 1 to F, g = 1 to G, h = 1 to H), and the three-dimensional region of interest Qo. Is set to B (f, g, h) (f = j + 1 to j + F, g = k + 1 to k + G, h = s + 1 to s + H). The evaluation function γ _AB (j, k, s) indicating the positional deviation of the positional deviation detection image data Vo with respect to the image data Vr is expressed by the following equation (2).

Then, the evaluation function γ _AB (j, k, s) of the above equation (2) is calculated while the positional deviation detection image data Vo is sequentially moved in the f direction, the g direction, and the h direction with respect to the treatment plan image data Vr. When γ _AB (j, k, s) shows a peak value at j = jx, k = kx, and s = sx, the positional deviation detection image data Vo is in the f direction with respect to the treatment planning image data Vr. Are detected as misaligned by jx voxels, kx voxels in the g direction, and sx voxels in the h direction. However, N in the above formula (2) represents the product of the number of voxels in the f direction F, the number of voxels in the g direction, and the number of voxels in the h direction in the three-dimensional region of interest Qo.

  Next, the input unit 10 is an interactive interface including input devices such as a display panel, a keyboard, a trackball, a joystick, and a mouse, and includes patient information (a patient's age, sex, weight, medical history, treatment target site, etc.). ), Formulation of a treatment plan (radiation irradiation region, etc.) based on the treatment plan image data, input of various instruction signals, and the like.

  The system control unit 11 includes a CPU and an input information storage unit (not shown), and various information input or formulated by the input unit 10 is stored in the input information storage unit. On the other hand, the CPU performs position shift detection between the treatment plan image data and the position shift detection image data based on the above-described various information read from the input information storage unit and corrects the position shift of the patient 150 based on the detection result. Further, the calculation of the therapeutic radiation dose in consideration of the radiation dose for imaging at the time of acquisition of the positional deviation detection image data and the radiotherapy of the patient 150 using the therapeutic radiation dose are executed.

  Next, as shown in FIG. 6, the image acquisition apparatus 120 of this embodiment that collects X-ray CT image data as treatment plan image data and positional deviation detection image data includes an X-ray generation unit 21, projection data generation, and the like. Unit 22, rotating gantry unit 23, fixed gantry unit 24, image data generating unit 25, display unit 26, moving mechanism unit 27, input unit 28, image / imaging condition output unit 29, and system control unit 30.

  The X-ray generation unit 21 of the image acquisition device 120 generates an X-ray tube 211 that irradiates the patient 150 with X-rays and a high voltage that is applied between the anode and the cathode of the X-ray tube 211. A generator 212, an X-ray restrictor 213 for setting an irradiation range of X-rays radiated from the X-ray tube 211, and a slip ring 214 for supplying the above-described high voltage to the X-ray tube 211 of the rotary mount unit 23. I have. The X-ray tube 211 is a vacuum tube that generates X-rays, and emits X-rays by colliding electrons accelerated by a high voltage supplied from the high-voltage generator 212 with a tungsten target. On the other hand, the X-ray restrictor 213 is provided between the X-ray tube 211 and the patient 150, and has a function of narrowing X-rays emitted from the X-ray tube 211 to a predetermined imaging region and an X-ray irradiation intensity distribution on the patient 150. Has a function to set. For example, the X-ray beam radiated from the X-ray tube 211 is formed into a cone beam-shaped or fan beam-shaped X-ray beam corresponding to the imaging region.

  Next, the projection data generation unit 22 detects the X-rays transmitted through the patient 150, and performs current / voltage conversion and A / A on the detection signals of a plurality of channels output from the X-ray detector 221. A data acquisition unit (hereinafter referred to as a DAS (Data Acquisition System) unit) 222 that performs signal processing such as D conversion, and parallel / serial conversion, electrical / optical / electrical conversion, and serial for the output signal of the DAS unit 222 A data transmission circuit 223 that performs / parallel conversion is provided.

  The X-ray detector 221 of the projection data generation unit 22 includes a plurality of X-ray detection elements (not shown) that are two-dimensionally arranged. Each of the X-ray detection elements includes a scintillator that converts X-rays into light and light. It consists of a photodiode that converts it into an electrical signal. These X-ray detection elements are attached to the rotating gantry 23 along an arc centered on the focal point of the X-ray tube 211.

  On the other hand, the DAS unit 222 performs current / voltage conversion, A / D conversion, and the like on the detection signal of the X-ray detector 221. The data transmission circuit 223 includes a parallel / serial converter, an electrical / optical / electrical converter, and a serial / parallel converter (not shown), and the detection signal output from the DAS unit 222 is attached to the rotary mount 23. Is converted into time-series projection data of one channel in the parallel / serial converter, and is supplied to the serial / parallel converter attached to the fixed base 24 by optical communication using the electrical / optical / electrical converter. The

  Next, the projection data converted into one channel is converted into projection data of a plurality of channels by a serial / parallel converter and stored in the projection data storage unit of the image data generation unit 25.

  Note that the above-described data transmission method is not limited as long as signal transmission between the projection data generation unit 22 provided in the rotary gantry 23 and the image data generation unit 25 provided outside the fixed gantry 24 is possible. For example, a signal transmission device such as a slip ring described above may be used. In this case, the X-ray tube 211 and the X-ray diaphragm 213 of the X-ray generation unit 21 and the X-ray detector 221 and the DAS unit 222 of the projection data generation unit 22 face each other so as to sandwich the patient 150 therebetween. Mounted on the part 23.

  The image data generation unit 25 includes a projection data storage unit and a reconstruction processing unit (not shown), and the projection data generated by the projection data generation unit 22 uses the rotation angle information of the rotary mount unit 23 as incidental information. Saved in. On the other hand, the reconstruction processing unit has a program storage unit (not shown) in which various arithmetic processing programs are stored in advance, and the X-ray CT imaging in which the projection data read from the projection data storage unit is read from the program storage unit. A three-dimensional image data is generated by performing a reconstruction process using a suitable arithmetic processing program.

  The image data for treatment plan generated at the time of treatment planning in the image data generation unit 25 and the image data for position shift detection generated immediately before the radiation treatment are displayed on the monitor of the display unit 26, and further, the image / photographing is performed. It is supplied to the condition output unit 29.

  The display unit 26 displays the conversion processing unit that converts the treatment plan image data and the positional deviation detection image data generated by the image data generation unit 25 into a predetermined display format, and the conversion-processed image data described above. A monitor (both not shown) is provided.

  In this case, in the display unit 26, the treatment plan image data and the positional deviation detection image data obtained by using the units of the X-ray generation unit 21, the projection data generation unit 22, and the image data generation unit 25 are stored in the patient 150. It is confirmed whether or not the image data is effective for the treatment plan and positional deviation correction. If it is confirmed that the image data is effective, the image data is captured to the radiation therapy apparatus 110 via the image / imaging condition output unit 29. Is output.

  Next, the moving mechanism unit 27 rotates the gantry 23 to which the X-ray tube 211 of the X-ray generator 21 and the X-ray detector 221 of the projection data generator 22 are attached at high speed around the patient 150. Rotation mechanism, top plate moving mechanism for moving the top plate 131 on which the patient 150 is placed in the body axis direction (z direction in FIG. 6) or in the direction orthogonal to the body axis direction (x direction in FIG. 6), and gantry rotation A mechanism control unit (not shown) for controlling the mechanism and the top plate moving mechanism is provided.

  Then, the mechanism control unit of the moving mechanism unit 27 generates a gantry rotation control signal based on the imaging start instruction signal supplied from the input unit 28 via the system control unit 30, and uses this gantry rotation control signal as the gantry rotation mechanism. , The rotating gantry 23 to which the X-ray tube 211 and the X-ray detector 221 are attached is rotated at a high speed in a predetermined direction.

  The mechanism control unit described above generates a top plate movement control signal based on the top plate movement instruction signal supplied from the input unit 28 via the system control unit 30, and the top plate movement control signal is moved to the top plate. By supplying to the mechanism and moving the top plate 131 in the body axis direction or in a direction perpendicular to the body axis direction, the treatment target site of the patient 150 placed on the top plate 131 is formed in the central portion of the rotating mount unit 23. Place in the shooting field.

  The input unit 28 includes input devices such as a display panel, a keyboard, various switches, selection buttons, and a mouse, and inputs patient information, sets imaging conditions and image data generation conditions, and inputs various instruction signals. Note that the above imaging conditions include, for example, the tube voltage of the X-ray tube 211, the tube current and the irradiation time, the irradiation time interval, the imaging position, the scanning method, the slice section interval, the number of slice sections, the size of the imaging area, and the like. Data generation conditions include a reconstruction method, a reconstruction area size, a reconstruction matrix size, and the like.

  The image / imaging condition output unit 29 is connected to the image / imaging condition acquisition unit 5 of the radiation therapy apparatus 110 via a network or the like (not shown), and the treatment plan image data and the position shift detection generated by the image data generation unit 25 are performed. The imaging conditions at the time of collecting the image data supplied from the system control unit 30 are added to the image data for use and output to the radiation therapy apparatus 110.

  The system control unit 30 includes a CPU and an input information storage unit (not shown), and the above-described input information and setting information supplied from the input unit 28 are stored in the input information storage unit. Then, the CPU comprehensively controls the above-described units included in the image acquisition device 120 based on the input / setting information, thereby performing treatment planning image data and positional deviation detection images in the radiation treatment of the patient 150. Run data collection.

(Image data collection procedure by image collection device)
Next, a procedure for collecting treatment plan image data and positional deviation detection image data (hereinafter collectively referred to as image data) by the image collection apparatus 120 of the present embodiment having an X-ray CT imaging function is illustrated. This will be described with reference to the flowchart of FIG.

  Prior to the collection of image data for the patient 150, an operator who operates the image collection apparatus 120 inputs patient information, sets imaging conditions, sets image data generation conditions, and the like using the input device provided in the input unit 28. The input information and setting information are stored in the input information storage unit included in the system control unit 30 (step S1 in FIG. 7).

  Next, after placing the patient 150 on the top board 131 of the bed 130, the above-described operator inputs a top board movement instruction signal at the input unit 28 (step S2 in FIG. 7). On the other hand, the mechanism control unit of the moving mechanism unit 27 generates a top plate movement control signal based on the above-described top plate movement instruction signal supplied from the input unit 28 via the system control unit 30. Then, the top plate movement control signal is supplied to the top plate moving mechanism of the moving mechanism unit 27 to move the top plate 131 in the body axis direction or in a direction orthogonal to the body axis direction. The site to be treated of the patient 150 is placed in the imaging field formed at the center of the rotary mount 23 (step S3 in FIG. 7).

  Next, the operator inputs a shooting start instruction signal at the input unit 28 (step S4 in FIG. 7), and the mechanism control unit of the moving mechanism unit 27 is based on the above-described shooting start instruction signal supplied from the input unit 28. By supplying the gantry rotation control signal generated in this way to the gantry rotating mechanism of the moving mechanism unit 27, the rotating gantry unit 23 to which the X-ray tube 211 and the X-ray detector 221 are attached is rotated at a high speed at a predetermined angular velocity.

  On the other hand, the high voltage generator 212 of the X-ray generation unit 21 that has received the above-described imaging start instruction signal and imaging conditions via the system control unit 30, based on these pieces of information, the power required for the X-ray CT imaging ( A tube voltage and a tube current) are supplied to the X-ray tube 211 for a predetermined period to irradiate the patient 150 with X-rays. Then, the X-rays emitted from the X-ray tube 211 and transmitted through the patient 150 are converted into a charge (current) signal proportional to the transmitted dose in the X-ray detector 221 of the projection data generation unit 22 and passed through a switch group (not shown). To the DAS unit 222.

  The DAS unit 222 performs current / voltage conversion and A / D conversion on the current signal to generate time-series projection data of a plurality of channels, and the obtained projection data is detected by the X-ray detector 221. Element arrangement position information, rotation angle information, and the like are stored as incidental information in the projection data storage unit of the image data generation unit 25 (step S5 in FIG. 7).

  On the other hand, the reconstruction processing unit of the image data generation unit 25 reads out an arithmetic processing program corresponding to the reconstruction parameter of the image data generation condition initialized in step S1 from its own program storage unit. Then, the projection data read out together with the incidental information from the projection data storage unit is reconstructed using the above-described arithmetic processing program to generate three-dimensional image data, and the obtained image data is displayed on the display unit 26. (Step S6 in FIG. 7).

(Procedure for formulating treatment plan)
Next, a procedure for formulating a treatment plan by the radiation treatment apparatus 110 of this embodiment will be described with reference to the flowchart of FIG.

  When formulating a treatment plan for the treatment target region of the patient 150, each unit of the image collection device 120 collects treatment plan image data for the purpose of the treatment plan according to the procedure shown in the flowchart of FIG. 7 (step of FIG. 8). S11).

  Then, the image / imaging condition output unit 29 of the image acquisition device 120 adds the imaging conditions at the time of collection of the treatment plan image data supplied from the system control unit 30 to the obtained treatment plan image data, and performs radiotherapy. The image / imaging condition acquisition unit 5 of the radiotherapy apparatus 110 supplies the apparatus 110 with the above-described treatment plan image data supplied from the image acquisition apparatus 120 (step S12 in FIG. 8).

  Next, the display unit 7 converts the treatment plan image data supplied from the above-described image / imaging condition acquisition unit 5 via the system control unit 11 into a predetermined display format and displays the data on its own monitor (FIG. 8). Step S13), the operator observing the treatment plan image data displayed on the display unit 7 inputs a treatment plan based on the treatment target site information indicated in the treatment plan image data to the input unit 10 It is formulated using a device (step S14 in FIG. 8).

  In this case, the operator sets the irradiation direction and the irradiation region for the patient 150 as the above-described treatment plan, and further, the planned treatment radiation Go for the irradiation region is set to the age, sex, weight, medical history, treatment of the patient 150. Set based on the target.

  The obtained treatment plan is stored in the treatment plan storage unit of the data storage unit 6. The treatment plan image data supplied from the image / imaging condition acquisition unit 5 is stored in the image data storage unit of the data storage unit 6 (step S15 in FIG. 8).

(Radiotherapy procedure)
Next, the procedure of radiation therapy by the radiation therapy apparatus 110 of this embodiment will be described along the flowchart of FIG.

  When performing radiation treatment on a treatment target region of the patient 150, each unit of the image acquisition device 120 detects position displacement for the purpose of detecting position displacement of the patient 150 at the time of treatment planning and radiation treatment according to the procedure shown in the flowchart of FIG. Image data is generated (step S21 in FIG. 9).

  Next, the image / imaging condition output unit 29 of the image acquisition device 120 adds the imaging conditions at the time of collecting the positional deviation detection image data supplied from the system control unit 30 to the obtained positional deviation detection image data, and performs radiation. The image / imaging condition acquisition unit 5 of the radiation therapy apparatus 110 supplies the image data for position shift detection supplied from the image acquisition apparatus 120 with the above-described imaging conditions added thereto. Then, the obtained positional deviation detection image data is temporarily stored in the image data storage unit of the data storage unit 6 (step S22 in FIG. 9).

  On the other hand, the positional deviation detection unit 9 of the radiotherapy apparatus 110 reads the treatment plan image data and the positional deviation detection image data stored in the above-described image data storage unit. Then, a region of interest of a predetermined size is set for the treatment plan image data, and the treatment plan image is processed by correlation between the pixel of the treatment plan image data extracted from the region of interest and the pixel of the position deviation detection image data. The position shift of the image data for position shift detection with respect to the image data (that is, the difference between the position at the time of treatment planning of the patient 150 placed on the top board 131 and the position immediately before the radiation treatment) is detected (step S23 in FIG. 9). .

  Next, the mechanism control unit 43 of the moving mechanism unit 4 is based on the position shift detection result of the treatment plan image data and the position shift detection image data supplied from the position shift detection unit 9 via the system control unit 11. The generated top board movement control signal is supplied to the top board movement mechanism 42, and the top board movement mechanism 42 moves the top board 131 in a predetermined direction according to the top board movement control signal supplied from the mechanism control unit 43. The position of the patient 150 placed on the top board 131 at the time of radiotherapy is corrected to the position at the time of treatment planning (step S24 in FIG. 9).

  On the other hand, the radiation dose calculation unit 8 reads out the imaging conditions at the time of collection of the image data stored together with the positional deviation detection image data in the image data storage unit of the data storage unit 6 and is included in these imaging conditions. The X-ray dose Da (Gy) at the time of collecting image data for position shift detection is estimated based on the applied voltage and application time of the high voltage generator. Then, the obtained X-ray dose Da (Gy) is converted into an imaging radiation dose Ga (MU) having the same unit as the radiation dose for radiation therapy.

  Further, the radiation dose calculation unit 8 reads out the planned treatment radiation dose Go (MU) stored in the treatment plan storage unit of the data storage unit 6 and uses the obtained planned treatment radiation dose Go (MU) as described above. A radiotherapy dose Gx (MU) suitable for the radiotherapy is calculated by subtracting the radiographing dose Ga (MU) (step S25 in FIG. 9).

  Next, the radiation control unit 31 of the radiation generating unit 3 receives the calculation result of the therapeutic radiation dose Gx (MU) supplied from the radiation dose calculation unit 8 and based on the therapeutic radiation dose Gx (MU). By controlling the applied voltage and the application time in the high voltage generator of the radiation generator 32, the irradiation conditions of the therapeutic radiation emitted from the radiation generator 32 (that is, the irradiation intensity and the irradiation time of the therapeutic radiation) Is set (step S26 in FIG. 9).

  Next, the high voltage generator of the radiation generator 32 applies a high voltage having the above-described applied voltage and application time to the X-ray tube, and the X-ray tube is accelerated by the high voltage supplied from the high voltage generator. The therapeutic radiation having the therapeutic radiation dose Gx (MU) is radiated by colliding the electrons with the tungsten target. The therapeutic radiation emitted from the X-ray tube is applied to the radiation irradiation region of the patient 150 formed by the radiation restrictor 33, and the radiation treatment is performed on the treatment target region existing in the radiation irradiation region. (Step S27 in FIG. 9).

  According to the embodiment of the present disclosure described above, when performing radiotherapy by irradiating a treatment target site of a patient with a predetermined intensity of therapeutic radiation, when collecting image data for detecting misalignment preceding this radiotherapy By setting the radiation dose for radiotherapy in consideration of the radiation dose for radiography in, safe and effective radiotherapy becomes possible.

  In particular, since the radiation dose for imaging at the time of collecting image data for detecting misregistration is estimated based on the imaging conditions at the time of collecting the image data supplied from the image collecting device that collects the image data, accurate treatment is performed. The radiation dose can be easily calculated.

  Further, by comparing the treatment plan image data supplied from the image collection device and the position deviation detection image data, the position deviation between the position at the time of collecting the treatment plan image data and the position at the time of radiation treatment of the patient is detected. It becomes possible to detect accurately, and by correcting the positional deviation of the patient at the time of radiotherapy based on this positional deviation detection result, the radiotherapy based on the treatment plan can be executed accurately and safely.

  As mentioned above, although embodiment of this indication has been described, this indication is not limited to the above-mentioned embodiment, and it can change and carry out. For example, in the above-described embodiment, the case where an X-ray CT apparatus is used as the image acquisition apparatus 120 included in the radiation therapy system 100 has been described. However, the image acquisition apparatus 120 may be a normal X-ray imaging apparatus. Further, it may be a medical image diagnostic apparatus capable of imaging with other imaging radiation.

  Further, the treatment plan image data and the positional deviation detection image data generated by the image acquisition device 120 are three-dimensional projection data (volume data) generated by the projection data generation unit 22 as shown in the above-described embodiment. 3D image data obtained by performing reconstruction processing, and by extracting voxels in a predetermined section of the volume data (for example, a section parallel to the xz plane in FIG. 6). The obtained two-dimensional MPR (multi planar reconstruction) image data may be used.

  On the other hand, in the above-described embodiment, the case where the radiation dose for radiotherapy is calculated in consideration of the radiation dose for imaging at the time of collecting the image data for detecting misalignment is described. Alternatively, it may be performed based on the radiation dose for imaging at the time of collection of the treatment plan image data or the treatment plan image data and the positional deviation detection image data. For example, when it is not necessary to collect positional deviation detection image data, such as when radiotherapy based on this treatment plan is performed immediately after the treatment plan is formulated, when the image data for treatment plan is collected, The therapeutic radiation dose may be calculated in consideration of the imaging radiation dose. In addition, when other image data is additionally collected prior to the radiotherapy, it is desirable to further calculate the radiation dose for treatment in consideration of the radiation dose for imaging when collecting these image data. .

  Further, the positional deviation detection unit 9 and the radiation dose calculation unit 8 in the above-described embodiment use the treatment plan image data and the positional deviation detection image data stored in the image data storage unit of the data storage unit 6 to perform image data. In the above description, the positional deviation detection is performed using the positional deviation detection image data supplied from the image / imaging condition acquisition unit 5 and the treatment plan image data read from the image data storage unit. Detection may be performed.

  Note that each unit included in the X-ray fluoroscopic apparatus according to the present embodiment and the modification thereof may be a computer using a CPU, a RAM, a magnetic storage device, an input device, a display device, and the like as hardware. Can be realized. For example, the system control unit 11 of the radiation therapy apparatus 110 can realize various functions by causing a processor such as a CPU mounted on the computer to execute a predetermined control program. In this case, the above-described control program may be installed in advance in the computer, or may be stored in a computer-readable storage medium or installed in the computer of the control program distributed via the network. .

  As mentioned above, although some embodiment and its modification of this invention were demonstrated, these embodiment and modification are shown as an example, and are not intending limiting the range of 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.

DESCRIPTION OF SYMBOLS 110 ... Radiation therapy apparatus 1x ... Fixed mount frame 2x ... Rotating mount frame 3 ... Radiation generation part 31 ... Radiation control part 32 ... Radiation generator 33 ... Radiation restrictor 4 ... Movement mechanism part 41 ... Aperture movement mechanism 42 ... Top plate movement mechanism 43 ... Mechanism control unit 5 ... Image / imaging condition acquisition unit 6 ... Data storage unit 7 ... Display unit 8 ... Radiation dose calculation unit 9 ... Position displacement detection unit 10 ... Input unit 11 ... System control unit 120 ... Image collection device 130 ... Bed 131 ... Top plate 100 ... Radiation therapy system

Claims (9)

In a radiotherapy apparatus for performing radiotherapy on a treatment target site of a patient,
Image / imaging condition acquisition means for acquiring image data of the patient supplied prior to the radiotherapy from a separately installed image acquisition apparatus and imaging conditions at the time of collection of the image data;
A radiation dose calculating means for calculating a therapeutic radiation dose suitable for the radiotherapy based on the imaging conditions;
A radiation therapy apparatus comprising: radiation control means for setting a radiation irradiation condition in the radiation therapy based on a calculation result of the therapeutic radiation dose.   The radiation dose calculating means estimates the radiation dose for imaging at the time of collecting the image data based on the imaging conditions, and subtracts the radiation dose for imaging from a preset planned radiation dose for treatment. The radiation therapy apparatus according to claim 1, wherein the radiation dose is calculated.   A radiation generator having an X-ray tube for generating therapeutic radiation for the treatment target site, wherein the radiation control means is configured to generate the X-ray based on the therapeutic radiation dose calculated by the radiation dose calculation means; 2. The radiotherapy apparatus according to claim 1, wherein at least one of a high voltage applied to the tube and an application time are controlled.   The radiation dose calculating means includes imaging conditions at the time of collection of treatment plan image data collected by the image collection device for the purpose of treatment plan of the radiation treatment or a position in the patient treatment plan and a position immediately before the radiation treatment. The radiotherapy apparatus according to claim 1, wherein the radiation dose for treatment is calculated based on at least one of imaging conditions at the time of collecting image data for position shift detection collected for the purpose of position shift detection. .   Position shift detection means for detecting a position shift between the treatment plan image data and the position shift detection image data, and the treatment plan from the position immediately before the radiotherapy based on the detection result of the position shift. The radiotherapy apparatus according to claim 4, further comprising a top plate moving mechanism for moving to a position at.   A radiation restrictor having a multi-segment diaphragm and a diaphragm movement mechanism for moving the multi-segment diaphragm, the diaphragm movement mechanism based on the shape of the treatment target site indicated in the treatment planning image data The radiotherapy apparatus according to claim 4, wherein a radiation irradiation region in the radiotherapy is set by moving a multi-part diaphragm. In a radiotherapy system comprising a radiotherapy device that performs radiotherapy on a treatment target site of a patient, and an image acquisition device that collects image data of the patient,
A radiotherapy system comprising the radiotherapy apparatus according to any one of claims 1 to 6 as the radiotherapy apparatus.   The radiotherapy system according to claim 7, wherein the image acquisition apparatus is either an X-ray CT apparatus or an X-ray imaging apparatus. For a radiotherapy device that performs radiotherapy on the patient's target site,
An image / imaging condition acquisition function for acquiring the image data of the patient supplied prior to the radiotherapy from an separately installed image acquisition device and the imaging conditions at the time of collection of the image data;
A radiation dose calculation function for calculating a therapeutic radiation dose suitable for the radiotherapy based on the imaging conditions;
A control program for executing a radiation control function for setting a radiation irradiation condition in the radiation therapy based on a calculation result of the therapeutic radiation dose.

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