JP7281131B2 - Treatment planning device, treatment planning method and program - Google Patents

Description

The present invention relates to a treatment planning device, treatment planning method and program.

Particle beam therapy is a cancer treatment method that destroys cancer cells by irradiating charged particles accelerated by a particle beam accelerator to cancer-affected areas. A particle beam has the highest dose concentration near the end of its range. For this reason, it has the characteristic of reducing damage to healthy tissue by releasing a large amount of energy from cancer-affected areas. On the other hand, since a large amount of energy is emitted in a limited small area, highly accurate calculation and irradiation are required.

In recent years, the spot scanning method, in which a thin particle beam is used to irradiate a target so as to paint it over, is becoming a mainstream irradiation method. It is determined by an optimization calculation that a desired dose distribution can be formed by irradiation from what angle to what spot. This process is called treatment planning.

Treatment planning involves inputting the outline of the organ as a ROI (Region of Interest). In general, different organs have different sensitivities to radiation, for example, organs with mucous membranes (such as the intestine) are more damaged than bones when exposed to the same amount of radiation. An organ that is easily damaged by radiation is called an organ at risk (OAR). In many cases, a doctor performs the ROI input work, but in recent years, automatic input by software is also available.

An index for evaluating the dose distribution created by the treatment plan differs for each organ and is designated by a doctor. For example, a condition such as "the volume of organ A irradiated with X% or more of the prescribed dose must not exceed Y%" is used in the optimization calculation.

Fractionation is the process of dividing the dose required for treatment into a certain number of times. Considering the physical and mental burden on the patient, it is desirable to shorten the treatment period. Therefore, hypofractionated treatment has been proposed for the purpose of shortening the treatment period. This is a treatment method that increases the amount of radiation delivered at one time and reduces the number of days required for treatment.

In order to increase the amount of radiation irradiated at one time, it is necessary to ensure the safety of the treatment. Therefore, a method has been proposed in which the daily irradiation is further divided into multiple times, and treatment is performed while confirming the dose distribution formed by the actually irradiated particle beam. In this way, the difference between the planned dose distribution and the dose distribution formed by the actually irradiated beam (hereinafter sometimes referred to as effective dose) is minimized, and safe hypofractionated irradiation is performed.

Calculating the effective dose during treatment regardless of the number of divisions, and determining whether to continue or stop the treatment or recreate the treatment plan based on the result is called online adaptive treatment.

Patent Document 1 has a function of recording marker position data and proton beam irradiation data, synchronizes these marker position data and proton beam irradiation data based on time information, and records the marker position data at the time of spot irradiation. A particle beam dose evaluation system is disclosed that calculates the actual dose distribution of proton beam irradiation using proton beam irradiation data.

JP 2017-176533

In order to realize online adaptive treatment, data or log files of the position, dose, energy, and irradiation time of the beam emitted from the particle beam therapy system during treatment are acquired, and based on that, the effective dose is calculated. must be calculated. Moreover, if the daily irradiation is further divided into multiple times and treatment is performed while confirming the dose distribution formed by the actually irradiated particle beam, it is necessary to calculate the effective dose for each irradiation.

However, dose calculation of particle beams requires a process of convoluting two or three Gaussian distributions on a three-dimensional CT, requiring a long calculation time. Therefore, if the effective dose is calculated many times within the treatment time, the treatment time will be extended.

In addition to online adaptive therapy, there is a need to calculate the effective dose within the treatment time.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a treatment planning apparatus, a treatment planning method, and a program capable of calculating an effective dose at high speed.

In order to solve the above problems, a treatment planning apparatus according to one aspect of the present invention includes a display device that displays tomographic image information including an affected area, and a particle beam dose applied to at least one region of interest set on the affected area. An input device for accepting input of calculation designation information designating whether or not to calculate the distribution, and an arithmetic device for calculating the dose distribution of the region of interest for which dose distribution calculation is designated based on the calculation designation information.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to calculate an effective dose at high speed.

1 is a schematic configuration diagram showing a particle beam therapy system according to Example 1; FIG. 1 is a schematic configuration diagram showing a particle beam therapy system according to Example 1; FIG. 1 is a configuration diagram showing a treatment planning apparatus of Example 1. FIG. 2 is a configuration diagram showing functions of the dose calculation device of Example 1. FIG. 4 is a flow chart showing the operation of the particle beam therapy system according to Example 1 before irradiation. 4 is a flowchart showing treatment plan creation processing by the irradiation plan creation apparatus of Example 1. FIG. 5 is a flow chart showing a region of interest classification designation process by the dose calculation device of the first embodiment; FIG. 10 is a diagram showing an example of a screen displayed in the region-of-interest classification designation process by the dose calculation apparatus of Example 1; 4 is a flow chart showing the dose distribution calculation operation of the particle beam therapy system according to Example 1. FIG. FIG. 3 is a diagram for explaining the principle of dose distribution calculation by the dose calculation device of Example 1; FIG. 3 is a diagram for explaining the principle of dose distribution calculation by the dose calculation device of Example 1; FIG. 3 is a diagram for explaining the principle of dose distribution calculation by the dose calculation device of Example 1; FIG. 11 is a block diagram showing the functions of the dose calculation device of Example 3; 11 is a flow chart showing the dose distribution calculation operation of the particle beam therapy system according to Example 3. FIG. FIG. 11 is a diagram for explaining the gate width control operation by the dose calculation device of Example 3;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiments described below do not limit the invention according to the scope of claims, and that all of the elements described in the embodiments and their combinations are essential to the solution of the invention. is not limited.

A treatment planning apparatus that is an embodiment of the present invention is applied to a particle beam therapy system using particle beams such as proton beams and carbon beams. A particle beam therapy system is a system that treats, for example, a cancer-affected area by irradiating the affected area with particle beams. The particle beam used in the particle beam therapy system is not limited as long as it is a particle beam that has already been put into practical use, such as the above-mentioned proton beam and carbon beam, and will be put into practical use in the future.

In this specification, "information" and "data" have the same meaning and are used without particular distinction. Also, when "information" and "data" are described, there is no limitation on the number of items. Furthermore, there is no limit to its format. In addition, data saved and stored in a storage medium in a so-called table format are also "information" and "data".

FIG. 1 is a schematic configuration diagram showing a particle beam therapy system according to a first embodiment, to which a treatment planning apparatus according to a first embodiment is applied. A particle beam therapy system S of this embodiment has a particle beam therapy system 1 and a treatment planning system 2 . The particle beam therapy system S of this embodiment employs the spot scanning method.

The particle beam therapy system 1 irradiates the affected area with particle beams to treat the affected area.

The treatment planning device 2 has an irradiation planning device 3 and a dose calculation device 4 .

The irradiation plan creation device 3 determines the irradiation parameters of the particle beam with which the affected area is irradiated. The determined irradiation parameters include the gantry angle, energy, irradiation position, and irradiation amount for each spot. The irradiation planning device 3 can calculate the dose distribution when irradiation is performed with arbitrary particle beam irradiation parameters. Calculations are performed to optimize the irradiation parameters of the particle beam necessary to form a dose distribution that is covered by the dose. The irradiation plan creation device 3 calculates the dose distribution when irradiation is performed with the irradiation parameters obtained as a result of the optimization calculation, and presents it to the operator (including the doctor). When the doctor approves the dose distribution calculated by the irradiation planning system 3 , the irradiation planning system 3 sends a treatment plan including irradiation parameters to the particle beam therapy system 1 .

The irradiation planning apparatus 3 accepts input of a three-dimensional X-ray CT image, which is tomographic image information including an affected area, captured in advance by an X-ray CT apparatus, and based on this, a region of interest (ROI ).

The dose calculation device 4 receives ROI data including data on the contour of the region of interest from the irradiation plan creation device 3, and displays the ROI contour image superimposed on the X-ray CT image. Then, the dose calculation device 4 receives a designation input of ROI classification from an operator (including a doctor).

The dose calculation device 4 also accepts input of irradiation log data including data on irradiation positions and irradiation doses when the affected area is actually irradiated from the particle beam therapy system 1 . The dose calculation device 4 also receives input of kernel data from the irradiation plan generation device 3 . Based on the ROI classification, the dose calculation device 4 calculates the effective dose and index using the fluence map and kernel data obtained from the irradiation log data.

The irradiation plan creation device 3 re-optimizes (re-plans, corrects) the irradiation parameters of the particle beam in the remaining irradiation plans based on the effective dose and the like calculated by the dose calculation device 4 .

Details of the operation of the treatment planning device 2, particularly the irradiation planning device 3 and the dose calculation device 4 will be described later.

Although the irradiation planning device 3 and the dose calculating device 4 are shown separately in FIG. Thus, it is virtually configured within one treatment planning apparatus 2 .

FIG. 2 is a schematic configuration diagram showing a particle beam therapy system according to the first embodiment. The particle beam therapy system 1 of this embodiment has an accelerator, a beam transport system 13 , an irradiation nozzle 14 , a treatment table 15 and an irradiation controller 16 . In FIG. 2, examples of the injector 11 and the synchrotron accelerator 12 are shown as accelerators, but a cyclotron accelerator may be used. The beam transport system 13 has a rotating gantry, but may have a fixed irradiation port.

A particle beam generated and accelerated by the injector 11 enters the synchrotron accelerator 12 , is further accelerated by the synchrotron accelerator 12 , and is emitted to the beam transport system 13 .

The beam transport system 13 includes a plurality of bending magnets 13 a and quadrupole magnets (not shown), and is connected to the synchrotron accelerator 12 and the irradiation nozzle 14 . Part of the beam transport system 13 and the irradiation nozzle 14 are installed on a rotating gantry and can rotate together with the gantry. A particle beam emitted from the synchrotron accelerator 12 passes through the beam transport system 13, is converged by the quadrupole electromagnet, changes its direction by the bending electromagnet 13a, and enters the irradiation nozzle .

The irradiation nozzle 14 has a scanning electromagnet, a dose monitor and a beam position monitor (none shown). A scanning electromagnet deflects the proton beam so that it reaches a desired position in a plane perpendicular to the beam axis at the target position. A dose monitor is a monitor that measures the dose of a particle beam irradiated to a target. The beam position monitor is a monitor for indirectly measuring the irradiation position of the proton beam irradiated to the target by detecting the position through which the particle beam irradiated to the target passes. The particle beam that has passed through the irradiation nozzle 14 reaches a target within an irradiation target (not shown) on the treatment table 15 . When treating a patient such as cancer, the irradiation target represents the patient, and the target represents the affected area.

The treatment table 15 on which the object to be irradiated is placed can move in directions of three orthogonal axes based on instructions from the irradiation control device 16, and can also rotate about each axis. By these movements and rotations, the position of the irradiation target can be moved to a desired position.

The irradiation control device 16 is connected to the synchrotron accelerator 12, the beam transport system 13, the irradiation nozzle 14, the treatment table 15, etc., and controls these devices.

FIG. 3 is a block diagram showing the treatment planning device 2 of Example 1. As shown in FIG.

The treatment planning apparatus 2 is configured as a computer system having a microprocessor (CPU: Central Processing Unit in the figure) 21 , a memory 22 , a storage device 23 , a communication interface device 24 and a user interface device 25 , for example.

The storage device 23 is composed of, for example, a flash memory device, hard disk drive (HDD), etc., and stores computer programs such as an operating system 231 and a treatment planning program 232 . In addition to these computer programs 231 and 232 , software (not shown) such as driver software is also stored in the storage device 23 .

The microprocessor 21 reads the treatment planning program 232 stored in the storage device 23 into the memory 22 and executes it, thereby realizing the function of the treatment planning device 2 including the irradiation planning device 3 and the dose calculation device 4. .

The communication interface device 24 is a device for communicating with the irradiation control device 16 of the particle beam therapy system 1 . The user interface device 25 is a device for exchanging information with a user (doctor) who uses the treatment planning device 2 . The user interface device 25 includes an information output device and an information input device. Examples of information output devices include displays, printers, voice synthesizers, and the like. Examples of information input devices include keyboards, pointing devices, touch panels, voice recognition devices, and the like. For example, the calculation result of the treatment plan and the operation to the treatment plan program 232 are displayed on the display.

FIG. 4 is a configuration diagram showing the functions of the dose calculation device 4 of the first embodiment. The dose calculation device 4 of the present embodiment has a control section (arithmetic device) 40 , a storage section 41 , an input section (input device) 42 and a display section (display device) 43 .

The control unit 40 includes a microprocessor 201 and the like, and controls the dose calculation device 4 as a whole. The control unit 40 has a dose distribution calculation unit 401 , a display control unit 402 , a comparison unit 403 and a comparison result transmission unit 404 .

The dose distribution calculation unit 401 receives the dose distribution based on the calculation designation information that designates whether or not to calculate the dose distribution of the particle beam irradiated for at least one region of interest set in the affected area. Calculate the effective dose (dose distribution) of the specified region of interest. The effective dose calculation procedure performed by the dose distribution calculation unit 401 will be described in detail later.

The display control unit 402 generates a display control signal for displaying various images on the display, which is the information output device of the user interface device 205, and sends the display control signal to the display.

Specifically, the display control unit 402 displays the three-dimensional X-ray CT image (tomographic image information) received by the treatment planning apparatus 2 on the display, and displays the contour image of the region of interest extracted by the irradiation planning apparatus 3. It is superimposed and displayed on this X-ray CT image. Also, the display control unit 402 causes the display to display the result of comparison by the comparison unit 403 . A specific example of the comparison result by the comparison unit 403 will be described later.

The comparison unit 403 compares the effective dose calculated by the dose distribution calculation unit 401 with the reference value for the region of interest for which setting of the reference value is designated. This reference value is a reference value for the effective dose or a calculable index based on the effective dose, for the region of interest for which the calculation of the effective dose is designated and which is received by the input unit 42 . The input unit 42 accepts the necessity of setting the reference value and the reference value as the reference value designation information.

An example of the index is a dose condition indicating how much dose of particle beam is to be applied to the region of interest. Whether the effective dose for a certain region of interest exceeds or falls below this dose condition, it is necessary to reschedule or cancel the subsequent treatment plan. , etc., and the particle beam therapy system 1 stops particle beam irradiation. In addition, the comparison unit 403 notifies the operator (including the doctor) of the treatment planning apparatus 2 of the comparison result of the comparison unit 403 via the above-described display control unit 402 and display, and sometimes displays a warning.

The comparison result sending unit 404 sends the comparison result of the comparing unit 403 to the irradiation plan creating device 3 .

The storage unit 41 includes a memory 22, a storage device 23, and the like, and stores computer programs such as an operating system 231 necessary for the operation of the dose calculation device 4 and a treatment planning program 232 related to the operation of the dose calculation device 4. . In addition, the storage unit 41 temporarily stores various data in the control operation of the dose calculation device 4 .

Furthermore, the storage unit 41 stores irradiation log data 411, ROI data 412, kernel data 413, fluence map 414, tomographic image information 415, calculation designation information 416, reference value designation information 417, dose distribution data 418, and dose index data 419. Store. Some of these data have already been described, and the remaining data will be described in detail later.

The input unit 42 consists of an information input device of the user interface device 25 and the like, receives various data for the dose calculation device 4 , and sends the received data to the control unit 40 and the storage unit 41 . Examples of data accepted by the input unit 42 include calculation designation information and reference value designation information.

The display unit 43 includes a display or the like that is an information output device of the user interface device 25 and displays a screen on the display surface based on the display control signal generated by the display control unit 402 of the control unit 40 . Examples of screens displayed on the display surface by the display unit 43 include an X-ray CT image as tomographic image information, a contour image of a region of interest, a comparison result of the comparison unit 403, and the like.

FIG. 5 is a flow chart showing the operation of the particle beam therapy system S according to the first embodiment before irradiation.

First, the irradiation plan creating device 3 of the treatment planning device 2 creates a treatment plan (step S1). Details of the treatment plan creation process will be described later. Next, the irradiation plan creation device 3 transmits the treatment plan created in step S1 to the particle beam therapy system 1 (step S2), and the particle beam therapy system 1 receives the treatment plan (step S3).

Then, the irradiation plan creating apparatus 3 stores the kernel data 413 based on the treatment plan created in step S1 in the storage device 23 (step S4). Here, the kernel data 413 is data used when calculating the expected dose distribution in the patient's body including the affected area.

FIG. 6 is a flow chart showing treatment plan creation processing by the irradiation plan creation apparatus 3 of the first embodiment. The flowchart shown in FIG. 6 shows the detailed operation of step S1 in FIG.

First, the irradiation plan creating apparatus 3 reads an X-ray CT image of a patient to be irradiated (step S11). An X-ray CT device outside the particle beam therapy system S picks up this X-ray CT image. The timing of capturing an X-ray CT image by the X-ray CT apparatus is arbitrary. The X-ray CT apparatus may send an X-ray CT image to the irradiation plan creation apparatus 3 immediately after imaging, or the X-ray CT apparatus stores the X-ray CT image in its own or an external storage device, and prepares an irradiation plan. An X-ray CT image may be read when the creating device 3 starts the treatment plan creating process shown in FIG.

Next, the irradiation plan creation device 3 sends the X-ray CT image read in step S11 to the dose calculation device 4, and the dose calculation device 4 executes region of interest setting processing (step S12). Details of the region-of-interest setting process by the dose calculation device 4 will be described later.

Next, the irradiation planning apparatus 3 receives input for setting the direction of irradiation of the beam (step S13), and receives prescription input for the dose to be input to the affected area and important organs (step S14). The setting of the irradiation direction of the beam and the prescription of the dose to be input to the affected area and important organs are input by the doctor by operating the information input device of the user interface device 205 . The dose prescription includes, for example, information such as which affected areas should be irradiated with the beam, and which vital organs should be protected from the beam. Note that the execution order of steps S13 and S14 is arbitrary, and is not limited to the order shown in FIG.

Next, the irradiation plan creating device 3 optimizes the irradiation dose to each spot (step S15). Furthermore, after determining the irradiation angle and the irradiation dose for each spot, the irradiation planning device 3 calculates the dose distribution in the patient's body (step S16).

Then, the irradiation plan creating apparatus 3 displays the result of creating the treatment plan through the display, which is the information output device of the user interface device 25 (step S17), and saves the created treatment plan in the storage device 23 (step S18).

Until the doctor determines that the treatment plan is treatable, the irradiation plan creation apparatus 3 accepts setting inputs and prescription inputs from the doctor, and the irradiation plan creation apparatus 3 processes steps S13 to S18 based on the accepted inputs. repeat.

FIG. 7 is a flow chart showing a region of interest classification designation process by the dose calculation device 4 of the first embodiment. The flowchart shown in FIG. 7 shows the detailed operation of step S12 in FIG.

First, the control unit 40 of the dose calculator 4 receives the X-ray CT image and the contour image of the region of interest from the irradiation plan generator 3 (step S21). The control unit 40 stores the received X-ray CT image (tomographic image information 415 ) and contour image of the region of interest (ROI data 412 ) in the storage unit 41 .

Next, the display control unit 402 of the control unit 40 sends to the display unit 43 a display control signal for superimposing and displaying the contour image of the region of interest on the X-ray CT image received in step S21 (step S22). The display unit 43 displays the X-ray CT image and the contour image of the region of interest on the display surface based on the display control signal sent from the display control unit 402 .

FIG. 8 is a diagram showing an example of a screen displayed in the region-of-interest classification designation process by the dose calculation device 4 of the first embodiment. The display unit 43 displays a screen 50 having an X-ray CT image 51 and a contour image 52 of a region of interest displayed superimposed on the X-ray CT image 51 .

Returning to the flowchart of FIG. 7, it is determined whether or not there is a region of interest for which the dose distribution is desired to be confirmed (step S23). accepts an input specifying a region of interest from a doctor or the like (step S24). Next, the input unit 42 receives, from a doctor or the like, designation input of the classification of the region of interest for which the designation input was received in step S24 and the reference value of the dose condition (index) (step S25).

In FIG. 8, the display unit 43 displays a pull-down menu 53 for selecting which region of interest to accept. The input unit 42 accepts the input of the classification and reference value for the region of interest selected by the pull-down menu 53 .

The input unit 42 first accepts the following three types of classification inputs that can be registered in step S25. (1) the most important ROI, which monitors the effective dose, and recreates the treatment plan if the pre-determined dose conditions are not met; (2) the critical ROI, which monitors the effective dose, but (3) General ROI, does not calculate effective dose during treatment (prioritizes calculation efficiency over checking effective dose).

Although there are many regions of interest extracted by the irradiation planning apparatus 3, the regions of interest corresponding to organs whose effective dose should be monitored are limited among them, such as the dangerous organs described above. Therefore, the regions of interest whose effective doses should be monitored are classified, and the minimum effective doses are calculated and monitored for these regions of interest. As a result, the region of interest for which the dose distribution calculator 401 calculates the effective dose can be reduced, and the calculation speed of the dose distribution calculator 401 can be increased.

The classification of the region of interest that does not accept the designation input of the classification by the input unit 42 (that is, the default value) is (3) general ROI. That is, the input unit 42 does not need to accept a designation input for a region of interest that does not need to be monitored for the effective dose during treatment and that should not be confirmed. Since the dose distribution calculation unit 401 (3) does not calculate the effective dose for the region of interest classified as the general ROI, the effect of saving the capacity of the storage device 23 and the memory of the irradiation control device 16 that performs dose calculation during treatment is achieved. be.

The display unit 43 displays two check boxes 54 and 55 for specifying the classification of the region of interest. One check box 54 is a check box 54 for the input unit 42 to accept a designation input indicating that the effective dose is to be monitored for the region of interest selected by operating the pull-down menu 53 . The other check box 55 is a check box 55 for the input unit 42 to accept designation input of dose conditions for the region of interest selected by operating the pull-down menu 53 .

In FIG. 8, the region of interest for which the input unit 42 has received the designation input for the check boxes 54 and 55 is the above-described (1) designation input as the most important ROI, and the input unit 42 receives the designation input for the check box 54 only. The accepted region of interest is (2) designated input as the ROI of interest described above.

Furthermore, in FIG. 8, the display unit 43 displays boxes 56 and 57 for receiving numerical input for the reference value of the dose condition. A box 56 is a box 56 in which the input unit 42 accepts a numerical value input of Y% under the condition that "the volume of organ A irradiated with X% or more of the prescribed dose must not exceed Y%" as a reference value. On the other hand, a box 57 is a box 57 in which the input unit 42 receives an input of an effective dose numerical value (unit: Gy: gray) for determining whether or not to continue particle beam irradiation as a reference value.

When the input unit 42 accepts the operation input of the registration button 58 displayed by the display unit 43 in FIG. 8, the input unit 42 accepts the classification of the region of interest and the reference value that are being input at that time. The control unit 40 stores the information received by the input unit 42 in the storage unit 41 as calculation designation information 416 and reference value designation information 417 . After that, the control unit 40 returns to step S23 and continues the operation.

On the other hand, if it is determined that there is no region of interest whose dose distribution should be checked (no region of interest to be registered or the like already exists) (NO in step S23), the control unit 40 ends the operation shown in FIG.

FIG. 9 is a flow chart showing the dose distribution calculation operation of the particle beam therapy system S according to the first embodiment.

First, the irradiation plan creating device 3 of the treatment planning device 2 reads out the kernel data 413 stored in the storage device 23 in step S18 of FIG. The dose calculation device 4 reads the kernel data 413 sent from the irradiation plan creation device 3 (step S31).

On the other hand, the particle beam therapy system 1 irradiates the patient with particle beams (step S32). Then, when the particle beam therapy system 1 irradiates the patient with a certain dose (for example, every 0.5 Gy), the particle beam therapy system 1 transmits the irradiation log data 411 to the treatment planning system 2 (step S33). The irradiation log data 411 includes the irradiation amount measured by the dose monitor and the irradiation position measured by the beam position monitor.

The dose calculator 4 of the treatment planning system 2 waits for the irradiation log data 411 to be transmitted from the particle beam therapy system 1, and receives the irradiation log data 411 transmitted from the particle beam therapy system 1. (step S34).

Next, the dose distribution calculator 401 of the dose calculator 4 generates a fluence map 414 based on the irradiation log data 411 received in step S32 (step S35). Further, the dose distribution calculator 401 calculates effective doses for the regions of interest classified into categories (1) and (2) based on the fluence map 414 generated in step S35 (step S36).

Then, the display control unit 402 generates a display control signal for displaying the screen showing the effective dose calculated in step S36 on the display surface of the display unit 43, and sends the display control signal to the display unit 43. The display unit 43 displays a screen showing the effective dose on the display surface based on this display control signal (step S37).

FIG. 10 is a diagram for explaining the principle of dose distribution calculation by the dose calculation device 4 of the first embodiment.

The particle beam irradiated to the patient forms a virtual fluence map (fluence map) 414 . The fluence map 414 has elements j arranged in a matrix. Each fluence map element j has a value calculated based on the irradiation log data 411 and corresponding to the dose of the particle beam actually irradiated to the patient from the plane position of each element j of the fluence map 414 .

FIG. 11 is a diagram for explaining the principle of dose distribution calculation by the dose calculation device 4 of Example 1, and shows the kernel data 413 read in step S31.

Referring to FIG. 10, kernel data 413 indicates how the particle beam is emitted in each minute volume i of the region of interest 61 of the patient 6 when the particle beam is irradiated from each element j of the fluence map 414 into the patient's body. It is a set of values calculated for each element of the fluence map 414 (ratio) indicating how much is absorbed. In other words, the kernel data 413 represents the dose distribution formed in each micro volume i of the region of interest 61 when a unit dose (that is, the dose is assumed to be 1) is incident on each element j of the fluence map 414. It is a collection.

Each element of the kernel data 413 Kij indicates the influence of each element j of the fluence map 414 on the minute volume i of the region of interest 61, that is, dose contribution. A row 414a of the fluence map 414 shows the influence of each element j of the fluence map 414 on the microvolume i. Column 414b of fluence map 414 shows the dose distribution that each element j of fluence map 414 produces over all microvolumes i.

FIG. 12 is a diagram for explaining the principle of dose distribution calculation by the dose calculation device 4 of Example 1, and is a diagram showing an equation for calculating an effective dose by the dose distribution calculator 401. FIG.

The effective dose in the region of interest is represented by the product of kernel data 413 and fluence map 414 . Here, as shown in FIG. 12, the kernel data 413 and the fluence map 414 are respectively represented by matrices, so the effective dose of the region of interest is also represented as the product of these matrices.

A conventional procedure for calculating the effective dose of a region of interest involves convolution of two or three Gaussian distributions on a three-dimensional X-ray CT. Therefore, it takes a long time to calculate the effective dose of the region of interest each time a certain dose of particle beam irradiation is performed by the particle beam therapy system 1 . The procedure for calculating the effective dose by the dose distribution calculating unit 401 of the present embodiment is to obtain a matrix product as shown in FIG. As a result, the effective dose can be calculated faster than the general method.

Returning to FIG. 9, the comparison unit 403 compares the effective dose calculated in step S36 with the set reference value for the region of interest classified into category (1), and determines whether the effective dose satisfies the dose condition. (step S38). In determining whether the effective dose satisfies the dose condition, if the effective dose is substantially equal to the reference value, the comparison unit 403 determines that the dose condition is satisfied. is determined not to satisfy the dose condition.

The comparison unit 403 may set a range for the reference value when determining that the effective dose satisfies the dose condition. That is, if the effective dose is within ±Z1 or ±Z2% (both Z1 and Z2 are positive values) of the reference value, the comparison unit 403 can determine that the effective dose is substantially equal to the reference value.

Then, when the comparison unit 403 determines that the effective dose satisfies the dose condition (YES in step S38), the process returns to step S34, and the dose calculation device 4 receives the irradiation log data 411 from the particle beam therapy device 1. wait for

On the other hand, if the comparison unit 403 determines that the effective dose does not satisfy the dose condition (NO in step S38), the display control unit 402 causes the display unit 43 to display a warning display screen notifying that the effective dose does not satisfy the dose condition. A display control signal for displaying on the display surface is generated, and this display control signal is sent to the display unit 43 . The display unit 43 displays the warning display screen based on the display control signal sent from the display control unit 402 (step S39).

The comparison result sending unit 404 also sends an irradiation stop instruction signal to the particle beam therapy system 1 to instruct the particle beam therapy system 1 to stop the particle beam irradiation (step S39). The particle beam therapy system 1 stops particle beam irradiation to the patient based on the irradiation stop instruction signal sent from the comparison result sending unit 404 (step S40).

Then, the comparison result sending unit 404 sends the comparison result of the comparing unit 403 to the irradiation plan creating device 3 . The irradiation plan creating apparatus 3 recreates a treatment plan based on this comparison result (step S41), and transmits the recreated treatment plan to the particle beam therapy system 1 (step S42). The particle beam therapy system 1 receives the treatment plan transmitted from the irradiation plan creation device 3 (step S43), and irradiates a particle beam based on this treatment plan (step S44).

The re-creation of the treatment plan by the irradiation plan creation device 3 may be performed after the input unit 42 receives an instruction input from the doctor regarding the re-creation of the treatment plan. Further, when the input unit 42 receives an instruction input from the doctor regarding the continuation or termination of the treatment by the particle beam therapy system 1, the irradiation planning system 3 may not recreate the treatment plan.

According to this embodiment configured as described above, the display unit 43 displays the X-ray CT image 415 including the affected area, and the input unit 42 performs dose distribution calculation for at least one region of interest set in the affected area. The control unit 40, especially the dose distribution calculating unit 401, receives the input of the calculation designation information 416 designating the necessity, and calculates the dose distribution of the region of interest for which dose distribution calculation is designated based on the calculation designation information 416. there is

Therefore, according to the present embodiment, the dose distribution calculator 401 can calculate the dose distribution only for the region of interest for which calculation of the dose distribution is designated. Accordingly, it is possible to provide a treatment planning apparatus, a treatment planning method, and a program capable of calculating an effective dose at high speed.

As a result, when performing online adaptive therapy, particle beam irradiation can be performed after confirming the effective dose to the patient, and it is possible to accurately support the doctor's decision. Also, keeping the difference between the planned dose and the delivered effective dose within a very small range can provide safer treatment.

In the first embodiment described above, the kernel data 413 was created using the X-ray CT image (tomographic image information 415) at the time of treatment planning. Kernel data 413 can be created from the X-ray CT images on the day of exposure if there is a risk of significant changes.

Anatomical changes include weight gain or loss, tumor shrinkage, nasal congestion or tissue swelling. It is conceivable that the change causes a change in the range of the beam inside the body (that is, a change in the position where the beam stops). By creating the kernel data 413 in consideration of daily changes in the patient's body, safer treatment can be provided.

After taking the X-ray CT image of the patient on the day, the flowchart of FIG. If the flowchart of FIG. 5 has already been executed once for the same patient, the organ name or identification number for the region of interest, the ROI data 412 including the contour image of the region of interest, the calculation designation information 416, the reference value The specified information 417 is automatically transferred to the new X-ray CT image.

This reduces the doctor's operating time. In addition, calculation of kernel data 413 can proceed in parallel with other treatment preparations (for example, positioning of the patient), thereby reducing time loss due to replacement of X-ray CT images.

FIG. 13 is a configuration diagram showing the functions of the dose calculation device 4 of Example 3. As shown in FIG. In addition, in the following description, the same reference numerals are given to the same constituent elements as in the first embodiment, and the description thereof will be simplified.

In order to accurately irradiate a tumor that changes position due to respiration in the trunk, especially in the vicinity of the lungs, a moving body tracking irradiation technique has been developed (eg, Japanese Patent No. 5976474). In the moving body tracking irradiation, an X-ray fluoroscopic image of the vicinity of the tumor is taken at a constant frequency (for example, 30 times per second). By analyzing the X-ray fluoroscopic image with a computer, the position of the tumor is obtained, and when the tumor position is within a preset range, a gate signal indicating that irradiation is possible is transmitted to the irradiation device. The beam is emitted while the gate signal indicating that the irradiation device is ready for irradiation rises.

The analysis of the tumor position includes a method of analyzing the movement of a marker artificially inserted in the vicinity of the tumor and a method of analyzing the position using only the image data of the patient's organs.

Moving body tracking irradiation technology has made it possible to irradiate moving organs with high precision. On the other hand, if the tumor moves out of place, the beam cannot be delivered, which can increase treatment time. If the width of the gate signal is wide (that is, if the rising time is long), the irradiation time is increased and the treatment time is shortened. Here, precision and time are in a trade-off relationship.

The dose calculation device 4 of this embodiment shown in FIG. Identical to the element.

The control signal sending unit 405 sends a control signal for controlling the irradiation range of the particle beam applied to the region of interest based on the comparison result of the comparing unit 403 . The control signal here is, for example, a gate signal sent to the particle beam therapy system 1 .

FIG. 14 is a flow chart showing the dose distribution calculation operation of the particle beam therapy system S according to the third embodiment.

In the flowchart shown in FIG. 14, steps S51 to S57 are the same as steps S30 to S37 in the flowchart of the first embodiment shown in FIG.

Next, the comparison unit 403 compares the effective dose T and the dose index C (step S58). As a result, when the comparison unit 403 determines that the effective dose T is smaller than the dose index C (T<C in step S58), the control signal transmission unit 405 changes the gate signal currently being transmitted to the particle beam therapy system 1. Control is performed to widen the width (step S59). Further, when the comparison unit 403 determines that the effective dose T is greater than the dose index C (T>C in step S58), the control signal transmission unit 405 controls the width of the gate signal currently being transmitted to the particle beam therapy system 1. is narrowed (step S60). Then, when the comparison unit 403 determines that the effective dose T is substantially equal to the dose index C (T=C in step S58), the process returns to step S54, and the dose calculation device 4 receives the irradiation log data 411 from the particle beam therapy device 1. is waiting to be sent.

Then, after controlling to widen or narrow the gate signal, the control signal sending unit 405 sends the changed gate signal to the particle beam therapy system 1 (step S61). The particle beam therapy system 1 changes the gate signal used for particle beam irradiation based on the gate signal received from the dose calculation device 4 (step S62).

FIG. 15 is a diagram for explaining the operation of gate width control by the dose calculation device 4 of the third embodiment. When a safe dose index _C0 is set as the dose index C, the control signal sending unit 405 feeds back the width of the gate signal according to the degree of achievement of the index, and after a certain period of time, the most efficient gate width for the patient under treatment. can be controlled to stabilize.

Therefore, according to this embodiment, since the dose distribution calculator 401 calculates the effective dose, it is possible to adjust the width of the gate signal while confirming the accuracy of the effective dose with respect to the dose index. Thereby, according to the dose calculation device 4 of the present embodiment, the accuracy of irradiation and the irradiation time can be optimized.

In addition, according to the dose calculation device 4 of the present embodiment, the treatment time is shortened by widening the width of the gate signal on the premise that the dose condition based on the past treatment experience, which does not affect the treatment effect, is always satisfied. effect is obtained.

In this embodiment, the particle beam therapy system 1 transmits the relationship between the tumor position and time monitored by moving body tracking to the dose calculation device 4, and the particle beam therapy system 1, in addition to the dose and the irradiation position, Time information can be sent to the dose calculator 4 . This makes it possible for the dose calculation device 4 to reflect the amount of movement of the tumor on the irradiation position and create a fluence map 414 that takes body movement into account.

Modification

In addition, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described 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 described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

As an example, Examples 1 to 3 described above show an example in which the effective dose is calculated for each constant dose. The timing for calculating the effective dose is not limited to these examples, and for example, the timing for calculating the effective dose can be determined by the energy, irradiation angle, and time of the particle beam.

Further, in the first to third embodiments, the irradiation plan creation device 3 and the dose calculation device 4 are described as being implemented by common hardware, but they may be implemented by different hardware.

Further, the hardware constituting the dose calculator 4 includes a GPU (Graphics Process Unit). If the matrix multiplication of the dose kernel and the fluence map is processed in parallel using a GPU, the computation speed will be further increased.

Furthermore, in Examples 1 to 3, an example of calculating the effective dose for each fixed dose was shown (for example, the effective dose is calculated and displayed each time 0.5 Gy is irradiated). Of course, it is not always necessary to keep the irradiation dose constant.

In hypofractionation, for example, when the patient needs to be irradiated with 10 Gy, 0.5 Gy is first irradiated and paused. The effective dose is then calculated and the dose distribution or a measure computable from the dose distribution is compared with the measures in the treatment plan. If the targets in the treatment plan have been achieved, then the delivered dose may be increased to 1 Gy, then paused and the effective dose calculated. It is also conceivable to implement a function that automatically repeats this process until all the necessary doses of 10 Gy for treatment have been irradiated.

With this function, it is possible to reduce the number of confirmations of the effective dose and provide efficient treatment when safe treatment can be expected.

Further, each of the above configurations, functions, processing units, processing means, and the like may be realized by hardware, for example, by designing them in an integrated circuit. Moreover, each of the above configurations, functions, etc. may be realized by software by a processor interpreting and executing a program for realizing each function. Information such as programs, tables, and files that implement each function can be stored in a recording device such as a memory, a hard disk, or an SSD, or a recording medium such as an IC card, an SD card, or a DVD.

Further, the control lines and information lines indicate those considered necessary for explanation, and not all control lines and information lines are necessarily indicated on the product. In practice, it may be considered that almost all configurations are interconnected.

S... Particle beam therapy system 1... Particle beam therapy device 2... Treatment planning device 3... Irradiation plan creation device 4... Dose calculation device 40... Control unit (arithmetic device) 41... Storage unit 42... Input unit (input device) 43... Display unit (display device) 401... Dose distribution calculation unit 402... Display control unit 403... Comparison unit 404... Comparison result sending unit 405... Control signal sending unit 411... Irradiation log data 412... ROI data 413... Kernel data 414... Fluence map 415 ... Tomographic image information 416 ... Calculation designation information 417 ... Reference value designation information 418 ... Dose distribution data 419 ... Dose index data

Claims (12)

a display device that displays tomographic image information including an affected area;
an input device that receives input of calculation designation information that designates whether or not to calculate the dose distribution of the particle beam irradiated for at least one region of interest set in the affected area;
and an arithmetic device for calculating the dose distribution of the region of interest for which calculation of the dose distribution is designated based on the calculation designation information. 2. The treatment planning apparatus according to claim 1, wherein said arithmetic unit has a display control unit for sending a display control signal for superimposing and displaying said region of interest on said tomographic image information to said display device. 2. The treatment planning apparatus according to claim 1, wherein the arithmetic unit has a dose distribution calculation unit that calculates the dose distribution of the region of interest for which calculation of the dose distribution is designated based on the calculation designation information. The input device inputs reference value designation information that designates whether or not to set a reference value of the dose distribution or an index that can be calculated based on the dose distribution for the region of interest for which calculation of the dose distribution is designated. 2. The treatment planning device of claim 1, which receives a 5. The treatment planning apparatus according to claim 4, wherein said input device receives, as said reference value designation information, input of said reference value for said region of interest for which setting of said reference value has been designated. The computing device is
a comparison unit that compares the calculated dose distribution with the reference value for the region of interest for which the setting of the reference value is specified;
6. The treatment planning apparatus according to claim 5, further comprising a display control section for sending a display control signal for displaying a comparison result by said comparison section to said display device. The treatment planning device has an irradiation plan creation device that creates an irradiation plan for a particle beam to be irradiated to the region of interest,
7. The treatment planning apparatus according to claim 6, wherein said arithmetic unit has a comparison result sending unit for sending a comparison result by said comparing unit to said irradiation planning apparatus. 7. The treatment planning apparatus according to claim 6, wherein the arithmetic unit has a control signal sending unit that sends a control signal for controlling the irradiation range of the particle beam applied to the region of interest based on the result of comparison by the comparing unit. . 9. The treatment planning apparatus according to claim 8, wherein said control signal sending unit sends, as said control signal, a signal for controlling a width of a gate signal for setting said irradiation range. 2. The treatment planning apparatus according to claim 1, wherein the arithmetic unit updates the set region of interest and the calculation designation information when the tomographic image information is updated. Display tomographic image information including the affected area,
Receiving input of calculation designation information designating whether or not to calculate the dose distribution of the particle beam irradiated with respect to at least one region of interest set in the affected area;
A treatment planning method performed by a treatment planning apparatus that calculates the dose distribution of the region of interest for which calculation of the dose distribution is specified, based on the calculation specifying information. A computer program executed by a computer, comprising:
a display function for displaying tomographic image information including the affected area;
an input function that accepts input of calculation designation information that designates whether or not to calculate the dose distribution of the particle beam irradiated for at least one region of interest set in the affected area;
and a computing function of calculating the dose distribution of the region of interest for which calculation of the dose distribution is designated, based on the calculation designation information.

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