Radiation therapy planning support device, radiation therapy planning support method, and radiation therapy system

Abstract

To assist in determining whether a treatment plan needs to be revised. [Solution] The radiotherapy planning support device according to the embodiment comprises an acquisition unit, an extraction unit, a generation unit, and a display control unit. The acquisition unit acquires a treatment plan corresponding to the radiotherapy to be performed on the patient, which includes the irradiation conditions of the radiation used in the radiotherapy, and a pre-treatment image obtained by imaging the patient before the radiotherapy based on the treatment plan is performed. The extraction unit extracts the contour of at least one of the tumor and the organ at risk included in the pre-treatment image. The generation unit calculates the cumulative value of the radiation dose irradiated to at least one of the tumor and the organ at risk corresponding to the contour extracted by the extraction unit when the radiotherapy is performed based on the treatment plan, and generates evaluation information based on the cumulative value. The display control unit causes the evaluation information to be displayed on the display unit.

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to a radiotherapy planning support device, a radiotherapy planning support method, and a radiotherapy system radiotherapy planning support device.

Background Art

[0002] In radiotherapy, there is an Adaptive Radiotherapy (ART) technique in which, before treatment by a radiotherapy device, the area around the irradiation region of a patient is imaged using a medical imaging device, and the necessity of replanning the treatment plan is determined using the captured image. In the ART technique, a treatment plan including one or more fractions (radiation irradiations) is created in advance. In each fraction, radiotherapy is performed according to the treatment plan. In the treatment plan, the irradiation conditions in each fraction are set so that the dose irradiated to the tumor to be treated and the organs at risk (OARs) adjacent to the tumor satisfy specified conditions. Also, medical imaging devices such as an X-ray diagnostic device, a computed tomography (CT) device, and a magnetic resonance imaging (MRI) device are often placed in the same room as the radiotherapy device, and imaging of the patient is performed by the medical imaging device before radiotherapy by the radiotherapy device. The operator checks the image captured before treatment and determines the necessity of replanning. When it is determined that replanning is necessary, replanning of the treatment plan is carried out.

[0003] During radiation therapy, the location and shape of tumors and organs at risk may change from those planned during the treatment planning stage. In such cases, if treatment is carried out according to the irradiation conditions set during the treatment planning stage, the conditions considered during the planning stage may not be met. For example, the initially assumed radiation dose may not reach the tumor, or the organs at risk may not meet the initially planned dose constraints. In such cases, it is preferable to revise the treatment plan before performing the treatment. On the other hand, if revision is not necessary, it is preferable not to revise the plan to minimize the burden on the patient. However, it is difficult to determine whether revision is necessary from images taken before treatment. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. Hei 2-200275 [Overview of the project] [Problems that the invention aims to solve]

[0005] One of the problems that the embodiments disclosed in this specification and drawings aim to solve is to assist in determining whether or not a treatment plan needs to be revised. However, the problems that the embodiments disclosed in this specification and drawings aim to solve are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described later can also be positioned as other problems. [Means for solving the problem]

[0006] The radiotherapy planning support device according to the embodiment comprises an acquisition unit, an extraction unit, a generation unit, and a display control unit. The acquisition unit acquires a treatment plan corresponding to the radiotherapy to be performed on the patient, which includes the radiation irradiation conditions used in the radiotherapy, and a pre-treatment image obtained by imaging the patient before the radiotherapy based on the treatment plan is performed. The extraction unit extracts the contour of at least one of the tumor and the organ at risk included in the pre-treatment image. The generation unit calculates the cumulative dose of radiation irradiated to at least one of the tumor and the organ at risk corresponding to the contour extracted by the extraction unit when the radiotherapy is performed based on the treatment plan, and generates evaluation information based on the cumulative value. The display control unit causes the evaluation information to be displayed on the display unit. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of the configuration of a radiotherapy system according to an embodiment. [Figure 2] Figure 2 shows an example of the configuration of a radiotherapy planning support device according to the embodiment. [Figure 3] Figure 3 is a flowchart illustrating the flow of adaptive radiotherapy using the radiotherapy system according to the embodiment. [Figure 4] Figure 4 is a flowchart illustrating the processing procedure by the radiation therapy planning support device according to this embodiment. [Figure 5] Figure 5 shows an example of a display screen shown in the radiation therapy planning support device according to the embodiment. [Figure 6] Figure 6 shows an example of the first display area in Figure 5. [Figure 7] Figure 7 shows an example of the second display area in Figure 5. [Figure 8] Figure 8 shows an example of the third display area in Figure 5. [Figure 9] Figure 9 shows an example of the fourth display area in Figure 5. [Figure 10] Figure 10 shows an example of a display screen related to a modified example. [Figure 11] Figure 11 shows an example of a display screen related to a modified example. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of a radiotherapy system and a radiotherapy planning support method, including a radiotherapy planning support device, will be described in detail with reference to the drawings. In the following description, components having substantially the same function and configuration will be denoted by the same reference numerals, and redundant explanations will be given only when necessary.

[0009] (First Embodiment) Figure 1 shows an example of the configuration of a radiotherapy system 1 according to the first embodiment. The radiotherapy system 1 is a system that plans a treatment plan for radiotherapy for a patient and executes radiotherapy according to that treatment plan. The radiotherapy system 1 is also a system that executes radiotherapy using appropriate radiotherapy. As shown in Figure 1, the radiotherapy system 1 includes a planning image acquisition device 2, a radiotherapy planning device 3, a pre-treatment image acquisition device 4, a radiotherapy planning support device 5, and a radiotherapy device 6. The planning image acquisition device 2, the radiotherapy planning device 3, the pre-treatment image acquisition device 4, the radiotherapy planning support device 5, and the radiotherapy device 6 are connected to each other so as to be able to communicate with each other via a network. The various types of data dealt with in this specification are typically digital data.

[0010] The planning image acquisition device 2 is a medical imaging diagnostic device that performs medical imaging on patients who are subjects of radiotherapy and generates planning images used for treatment planning. The planning images are anatomical images generated by imaging the tumor and organs at risk during treatment planning. The tumor is the target of treatment. Organs at risk are tissues that require careful control of the radiation dose during radiotherapy. Furthermore, organs at risk are normal tissues adjacent to the tumor being treated and are highly radiosensitive. If there are no organs at risk around the tumor, the planning image may include only the tumor. If there are multiple organs at risk around the tumor, the planning image may include multiple organs at risk.

[0011] The planning image acquisition device 2 may be any modality device capable of generating planning images. Examples of modality devices include CT scanners, MRI scanners, cone-beam CT scanners, nuclear medicine diagnostic devices, etc. The medical images are transmitted to, for example, the radiation therapy planning device 3.

[0012] The radiotherapy planning device 3 is a computer that creates a treatment plan for a patient using planning images generated by the planning image acquisition device 2. The treatment plan is transmitted to the radiotherapy planning support device 5. The treatment plan is a plan corresponding to the radiotherapy to be performed on the patient. The treatment plan includes the radiation irradiation conditions used in radiotherapy. The treatment plan also includes the radiation irradiation conditions for each fraction (hereinafter referred to as fraction) of multiple radiation irradiations to the irradiation field including the tumor. The irradiation conditions include the irradiation field and the irradiation dose index value. The irradiation field is the area to which radiation is irradiated. The irradiation dose index value is the dose index value of the radiation irradiated. The dose index value includes the total dose, which shows the total amount of radiation irradiated, and the dose rate, which shows the dose irradiated per unit time. The treatment plan also includes the predicted dose index value for each fraction. The predicted dose index value is an index value calculated during radiotherapy planning, and is a predicted value of the dose index value irradiated at the position corresponding to each pixel of the planning image. Specifically, the predicted dose index value includes the predicted dose value, which is the predicted total dose, and the predicted dose value, which is the predicted dose rate.

[0013] For example, the radiotherapy planning system 3 extracts the contours of tumors and organs at risk from planning images, sets the radiation irradiation conditions for each fraction included in the treatment plan, and calculates a predicted dose index value based on the set irradiation conditions. In this process, the radiotherapy planning system 3 sets the irradiation conditions so that the dose irradiated to the tumor meets the required dose and the dose irradiated to the organs at risk meets the dose constraint.

[0014] The required dose is the dose necessary to irradiate the tumor for treatment. For example, for the treatment of a tumor, it is determined that the "D95" of the tumor should be 60 Gy or more as the required dose. "D95" is the dose that encompasses the upper 95% of the volume of the tumor on the dose volume histogram (DVH). In other words, "D95" is the minimum value of the radiation dose irradiated in the range from the top to a predetermined ratio (95 [%]) on the dose volume histogram. That is, "D95" is the reference value when the volume ratio of the region irradiated with a dose exceeding the reference value becomes a predetermined value (95 [%]). For example, the irradiation conditions for each fraction are set so that the "D95" of the tumor matches the prescribed dose. By setting the irradiation conditions so that the "D95" of the tumor becomes 60 Gy or more, the prescribed dose is administered to 95% of the tumor, and a sufficient dose is irradiated to the tumor.

[0015] The dose constraint defines the maximum value of the dose of radiation that can be irradiated to the risk organ in the treatment plan. For example, it is stipulated by the dose constraint that the "V50" of the risk organ should be suppressed to 25% or less. "V50" is the volume ratio of the region irradiated with a dose of 50 Gy or more. That is, "V50" is the volume ratio of the region irradiated with a dose exceeding the reference value (50 [Gy]). For example, the irradiation conditions for each fraction are set so that the "V50" of a certain risk organ becomes 25% or less. By setting the irradiation conditions so that the "V50" of the risk organ becomes 25% or less, the dose irradiated to the risk organ can be suppressed.

[0016] The pre-treatment imaging device 4 is installed in the treatment room where the radiotherapy device 6 is installed. The pre-treatment imaging device 4 is a medical imaging diagnostic device that performs medical imaging on the patient immediately before treatment and generates pre-treatment images used to verify the treatment plan. Pre-treatment images are images obtained by imaging the patient before radiotherapy is performed based on the treatment plan. For example, a pre-treatment image is an anatomical image of the tumor and organs at risk immediately before the fraction to be performed. Hereinafter, the fraction to be performed will be referred to as the target fraction. If there are no organs at risk around the tumor, the pre-treatment image may include only the tumor. Also, if there are multiple organs at risk around the tumor, the pre-treatment image may include multiple organs at risk. Pre-treatment images are taken immediately before treatment with the target fraction. The pre-treatment imaging device 4 may be any modality device capable of generating pre-treatment images. Examples of modality devices include CT scanners, MRI scanners, cone-beam CT scanners, nuclear medicine diagnostic devices, etc. The pre-treatment images are transmitted to, for example, the radiotherapy planning support device 5. In addition, in the radiotherapy system 1, the medical imaging diagnostic device used as the planning imaging device 2 and the medical imaging diagnostic device used as the pre-treatment imaging device 4 may be provided separately, or one medical imaging diagnostic device may be used for both the planning imaging device 2 and the pre-treatment imaging device 4.

[0017] When performing the target fraction, the size and shape of the tumor or organ at risk may have changed over time since the treatment plan was created. Therefore, the contours of the tumor or organ at risk may have changed in the pre-treatment images compared to the planning images. As a result, if the target fraction is performed according to the irradiation conditions set during treatment planning, the dose delivered to the tumor may not meet the required dose, or the dose delivered to the organ at risk may not meet the dose constraints.

[0018] The radiotherapy planning support device 5 is installed in a treatment room where the radiotherapy device 6 is installed or in a control room adjacent to the treatment room. The radiotherapy planning support device 5 is a computer that uses the pre-treatment image generated by the pre-treatment imaging device 4 to verify the effectiveness of the treatment plan created by the radiotherapy planning device 3 and supports the determination of whether replanning of the treatment plan is necessary. The determination of whether replanning is necessary may be automatically performed by the radiotherapy planning support device 5 or manually performed by an operator's input. If replanning is not necessary, the radiotherapy planning support device 5 transmits the treatment plan created by the radiotherapy planning device 3 to the radiotherapy device 6. If replanning is necessary, the radiotherapy planning support device 5 executes replanning of the treatment plan. At this time, the radiotherapy planning support device 5 resets the irradiation conditions for each unexecuted fraction so that the dose irradiated to the tumor to be treated satisfies the required dose and the dose irradiated to the risk organ satisfies the dose constraint, based on the contours of the tumor and the risk organ extracted from the pre-treatment image. Thereafter, the radiotherapy planning support device 5 transmits the treatment plan after replanning to the radiotherapy device 6. That is, when an instruction to generate a new treatment plan (second treatment plan) different from the current treatment plan (first treatment plan) is input, the radiotherapy planning support device 5 generates a second treatment plan different from the current treatment plan (first treatment plan) based on the contour information.

[0019] The radiotherapy device 6 irradiates the patient with radiation according to the treatment plan transmitted from the radiotherapy planning support device 5. In this case, if the radiotherapy device 6 receives an instruction to generate a new treatment plan (second treatment plan) different from the current treatment plan (first treatment plan), it performs radiotherapy corresponding to the new treatment plan (second treatment plan). If no instruction to generate a new treatment plan (second treatment plan) is received, it performs radiotherapy corresponding to the current treatment plan (first treatment plan). The radiotherapy device 6 has a treatment stand and a treatment bed installed in the treatment room. The treatment bed moves its tabletop so that the patient's treatment area is approximately aligned with the isocenter. The treatment stand supports the irradiation head so that it can rotate around a rotation axis. The irradiation head irradiates radiation according to the treatment plan. When radiation is irradiated to the treatment area, the treatment area disappears or shrinks.

[0020] Next, we will explain the configuration of the radiation therapy planning support system 5. Figure 2 shows an example of the configuration of the radiotherapy planning support device 5. The radiotherapy planning support device 5 includes a storage device 51, a display device 52, an input device 53, a communication device 54, and a processing circuit 55. Data communication between the processing circuit 55, the storage device 51, the display device 52, the input device 53, and the communication device 54 is performed via a bus.

[0021] The storage device 51 is a storage device that stores various types of information, such as ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or semiconductor storage device. In addition to the above storage devices, the storage device 51 may also be a drive device that reads and writes various types of information to and from portable storage media such as CDs (Compact Discs), DVDs (Digital Versatile Discs), flash memory, or semiconductor memory elements. Furthermore, the storage device 51 may be located in another computer connected to the radiation therapy planning device 3 via a network.

[0022] The storage device 51 stores programs executed by the processing circuit 55, various data used in the processing of the processing circuit 55, and so on. As a program, for example, a program is used that is pre-installed on the computer from a network or a non-transient computer-readable storage medium, and that enables the computer to implement each function of the processing circuit 55. The storage device 51 may also be called a storage unit or memory.

[0023] The display device 52 displays various information according to the processing circuit 55. For example, the display device 52 outputs medical information generated by the processing circuit 55, a GUI (Graphical User Interface) for receiving various operations from the operator, etc. As the display device 52, for example, a liquid crystal display (LCD), a CRT (Cathode Ray Tube) display, an organic electroluminescent display (OELD), a plasma display, or any other display can be used as appropriate. The display device 52 may also be a projector. The display device 52 is an example of a display unit.

[0024] The input device 53 receives various input operations from the operator, converts the received input operations into electrical signals, and outputs them to the processing circuit 55. Specifically, the input device 53 can be a mouse, keyboard, trackball, switch, button, joystick, touchpad, touch panel display, or non-contact input circuit using an optical sensor, as appropriate. The input device 53 outputs an electrical signal corresponding to the input operation to the processing circuit 55. The input device 53 may also be a voice recognition device that converts voice signals collected by a microphone into instruction signals. In this specification, the input device 53 is not limited to those equipped with physical operating parts such as a mouse or keyboard. For example, an electrical signal processing circuit that receives an electrical signal corresponding to an input operation from an external input device provided separately from the device and outputs this electrical signal to the processing circuit 55 is also included as an example of the input device 53. The input device 53 may also be called an input interface or input unit.

[0025] The communication device 54 is an interface for data communication with other devices included in the radiotherapy system 1. For example, the communication device 54 receives treatment plans from the radiotherapy planning device 3 and pre-treatment images from the pre-treatment imaging device 4 via the network. The communication device 54 also transmits treatment plans to the radiotherapy device 6 via the network.

[0026] The processing circuit 55 is a processor that performs an acquisition function 551, a contour extraction function 552, an evaluation information generation function 553, an evaluation information display function 554, and a replanning function 555 by calling and executing a program in the storage device 51.

[0027] In Figure 2, the acquisition function 551, contour extraction function 552, evaluation information generation function 553, evaluation information display function 554, and replanning function 555 are described as being implemented by a single processing circuit 55. However, the processing circuit may be configured by combining multiple independent processors, and each processor may implement each function by executing a program. Furthermore, the acquisition function 551, contour extraction function 552, evaluation information generation function 553, evaluation information display function 554, and replanning function 555 may each be implemented as separate hardware circuits. The above description of each function performed by the processing circuit 55 is the same in the following embodiments and modifications. In addition, although the radiotherapy planning support device 5 is described as performing multiple functions in a single device, the multiple functions may be performed by separate devices. For example, each function performed by the radiotherapy planning support device 5 may be distributed and installed on different console devices or workstation devices.

[0028] In the above description, the term "processor" refers to circuits such as a CPU (central processing unit), a GPU (Graphics Processing Unit), an Application Specific Integrated Circuit (ASIC), a programmable logic device (e.g., a Simple Programmable Logic Device (SPLD)), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)). When the processor is a CPU, for example, it performs its functions by reading and executing a program stored in a memory circuit. On the other hand, when the processor is an ASIC, for example, instead of the program being stored in a memory circuit, the function is directly incorporated into the processor's circuit as a logic circuit. In this embodiment, each processor is not limited to being configured as a single circuit; multiple independent circuits may be combined to form a single processor and perform its functions. Furthermore, multiple components may be integrated into a single processor to perform its functions. The above description of "processor" is the same in the following embodiments and modifications.

[0029] The processing circuit 55 acquires pre-treatment images generated by the pre-treatment image acquisition device 4 and the treatment plan created by the radiotherapy planning device 3 through the acquisition function 551. The pre-treatment images and treatment plan are data related to the patient who is the subject of radiotherapy. The pre-treatment images are anatomical images generated by the pre-treatment image acquisition device 4 immediately before the target fraction to be performed. The processing circuit 55 that realizes the acquisition function 551 is an example of an acquisition unit.

[0030] The processing circuit 55, using the contour extraction function 552, extracts the contours of tumors and organs at risk in the acquired pre-treatment image based on the pre-treatment image, and identifies the image region enclosed by the extracted contours as a tumor or organ at risk. If there are multiple tumors or organs at risk, the processing circuit 55 extracts the contours of each tumor or organ at risk individually. Hereinafter, the contours extracted from the pre-treatment image will be referred to as pre-treatment contours. The processing circuit 55 that implements the contour extraction function 552 is an example of an extraction unit that extracts the contour of at least one of the tumors and organs at risk included in the pre-treatment image.

[0031] For example, the processing circuit 55 applies thresholding and image recognition processing to the pre-treatment image to extract the pre-treatment contours of tumors and organs at risk, and identifies the image region enclosed by the extracted pre-treatment contours as a tumor or organ at risk. Note that the extraction of pre-treatment contours may be performed manually by the operator. In this case, the processing circuit 55 displays the pre-treatment image on the display device 52. The operator uses an input device 53, such as a mouse or tablet pen, to draw the contours surrounding the tumor and organs at risk depicted in the pre-treatment image. The processing circuit 55 extracts the drawn contours as pre-treatment contours and identifies the image region enclosed by the pre-treatment contours as a tumor or organ at risk.

[0032] The processing circuit 55, using the evaluation information generation function 553, calculates the cumulative radiation dose irradiated to the tumor and risk organs when the target fraction is executed based on the extraction results of the pre-treatment contour, and generates evaluation information for verifying the treatment plan using the calculated cumulative value. Specifically, the processing circuit 55 first calculates the cumulative radiation dose accumulating in the tumor and risk organs respectively when the target fraction is executed, using the pre-treatment contour. At this time, the processing circuit 55 converts the past dose distribution of the tumor and risk organs into a dose distribution based on the pre-treatment contour. Subsequently, the processing circuit 55 calculates a predicted value of the dose irradiated by the target fraction relative to the pre-treatment contour at each location of the tumor and risk organs, and calculates the cumulative value when the target fraction is executed by adding the calculated predicted value to the dose in the converted dose distribution.

[0033] Subsequently, the processing circuit 55 generates evaluation information using the calculated cumulative values ​​for each position. The evaluation information includes information predicting what would happen if the target fraction were executed according to the treatment plan for the pre-treatment contour. The evaluation information is used to verify the treatment plan and to determine whether or not the treatment plan needs to be revised. As evaluation information, for example, various indicators for confirming the effectiveness of the treatment plan can be used, such as "D95" for the tumor and "V50" for the organ at risk. The evaluation information may also include graphs showing the time-series changes of the indicators and dose distributions for the tumor and organs at risk. Furthermore, the evaluation information may include predicted values ​​of the indicators at the completion of the treatment plan, predicted values ​​calculated during the treatment planning process, and indicators related to fractions executed in the past. The processing circuit 55 that realizes the evaluation information generation function 553 is an example of a generation unit that calculates the cumulative dose of radiation irradiated to at least one of the tumor and the organ at risk based on the treatment plan and generates evaluation information based on the cumulative value.

[0034] The processing circuit 55 displays the generated evaluation information on the display device 52 using the evaluation information display function 554. For example, in the evaluation information display function 554, the processing circuit 55 displays the evaluation information on the display screen that displays the pre-treatment image. In this case, the magnitude of the indicators included in the evaluation information may be represented by pixel values ​​or colors. The processing circuit 55 that implements the evaluation information display function 554 is an example of a display control unit that displays the evaluation information on the display unit.

[0035] The processing circuit 55 determines whether or not to perform a replanning of the treatment plan using the replanning function 555. If it determines to perform a replanning, it performs the replanning using the pre-treatment image. The processing circuit 55 may make the determination automatically based on evaluation information, or it may make the determination based on instructions input by an operator who has confirmed the evaluation information displayed on the display device 52. The processing circuit 55 that implements the replanning function 555 is an example of a replanning unit that performs a replanning of the treatment plan using contour information. Furthermore, the processing circuit 55 that implements the replanning function 555 is an example of a generation unit that generates a second treatment plan different from the current treatment plan (first treatment plan) based on contour information when an instruction is input to generate a new treatment plan (second treatment plan) different from the current treatment plan (first treatment plan).

[0036] In the replanning process, the radiation irradiation conditions for each unexecuted fraction included in the treatment plan are reset using the pre-treatment contour extracted from the pre-treatment image, and the predicted dose index is recalculated based on the reset irradiation conditions. At this time, the irradiation conditions are set so that the dose irradiated to the area enclosed by the pre-treatment contour of the tumor meets the required dose, and the dose irradiated to the area enclosed by the pre-treatment contour of the organs at risk meets the dose constraint. In this way, the irradiation conditions are set so that a sufficient dose is irradiated to the tumor, while the dose irradiated to the organs at risk is kept to a minimum.

[0037] Next, an example of the procedure for adaptive radiotherapy using radiotherapy system 1 will be described. Figure 3 is a flowchart showing a typical flow of adaptive radiotherapy. Note that the procedure described below is merely an example, and each step can be modified as appropriate. Furthermore, depending on the embodiment, steps in the procedure described below can be omitted, replaced, or added as appropriate.

[0038] In adaptive radiotherapy, first, planning images of the patient are taken by the planning image acquisition device 2 (step S101). The planning images are anatomical images including the tumor to be treated and organs at risk. The acquired planning images are transmitted from the planning image acquisition device 2 to the radiotherapy planning device 3.

[0039] Next, the radiotherapy planning device 3 creates a treatment plan for the patient using the planning images (step S102). At this time, based on the tumor contour and the contours of each organ at risk extracted from the planning images, the irradiation conditions for each fraction included in the treatment plan are set so that the radiation delivered to the tumor meets the required dose and the radiation delivered to each organ at risk meets the dose constraints. In other words, the treatment plan is generated so that the tumor receives sufficient radiation and the radiation delivered to each organ at risk is suppressed throughout the entire treatment plan. The treatment plan is transmitted from the radiotherapy planning device 3 to the radiotherapy planning support device 5.

[0040] When performing treatment according to the treatment plan, a pre-treatment image of the patient is taken by the pre-treatment imaging device 4 immediately before the target fraction to be performed in this treatment (step S103). The pre-treatment image is an anatomical image including the tumor and each organ at risk. The acquired pre-treatment image is transmitted from the pre-treatment imaging device 4 to the radiotherapy planning support device 5.

[0041] Next, the radiotherapy planning support device 5 performs a verification process to verify the treatment plan using pre-treatment images (step S104). The verification process determines whether or not the treatment plan needs to be revised due to changes in the tumor or each risk organ, and if revision is necessary, it executes the revision.

[0042] Figure 4 is a flowchart illustrating an example of the verification process performed by the radiation therapy planning support device 5. Note that the procedure described below is merely an example, and each step can be modified as appropriate. Furthermore, depending on the embodiment, steps in the procedure described below can be omitted, replaced, or added as appropriate.

[0043] In the verification process, first, the processing circuit 55 uses the acquisition function 551 to acquire pre-treatment images taken immediately before the target fraction from the pre-treatment image acquisition device 4 and to acquire the treatment plan from the radiotherapy planning device 3 (step S201). Next, the processing circuit 55 uses the contour extraction function 552 to extract the pre-treatment contours of the tumor and the pre-treatment contours of the organs at risk from the pre-treatment images (step S202).

[0044] Next, the processing circuit 55 generates evaluation information (step S203) when the target fraction is performed on the pre-treatment contour according to the irradiation conditions set in the treatment plan, using the evaluation information generation function 553. Here, we will explain the case where the evaluation information generates the "D95" of the tumor, the "V50" of the organ at risk, and the dose distribution of the cumulative values ​​for the tumor and organ at risk at the completion of the target fraction.

[0045] In step S203, the processing circuit 55 converts the tumor's past dose distribution into a dose distribution that follows the tumor's pre-treatment contour, calculates a predicted value of the dose irradiated to the area enclosed by the tumor's pre-treatment contour when the target fraction is executed according to the treatment plan, and adds the calculated predicted value to the converted dose distribution to calculate the cumulative value of the dose accumulated in the tumor when the target fraction is executed. Subsequently, the processing circuit 55 generates the tumor's dose distribution and dose-volume distribution using the cumulative value, and calculates the tumor's "D95" using the dose-volume distribution.

[0046] Furthermore, the processing circuit 55 converts the past dose distribution of the organ at risk into a dose distribution that follows the pre-treatment contour of the organ at risk, calculates a predicted value of the dose irradiated to the area enclosed by the pre-treatment contour of the organ at risk when the target fraction is executed according to the treatment plan, and adds the calculated predicted value to the converted dose distribution to calculate the cumulative value of the dose accumulated in the organ at risk when the target fraction is executed. Subsequently, the processing circuit 55 generates a dose distribution of the organ at risk using the cumulative value and calculates the "V50" of the organ at risk.

[0047] Next, the processing circuit 55 displays the evaluation information on the display device 52 using the evaluation information display function 554 (step S204). Figure 5 is a diagram showing an example of the display screen displayed on the display device 52. The display screen shown in Figure 5 displays an evaluation information display area 521 where the evaluation information is displayed, a first operation button 522 for performing the operation to execute a replan, a second operation button 523 for performing the operation to confirm the treatment plan, and a plan display area 524 where the contents of the treatment plan are displayed. The evaluation information display area 521 has a first display area 5211 that displays "D95" for the tumor, a second display area 5212 that displays "V50" for the organ at risk, a third display area 5213 that displays the dose distribution of the cumulative values ​​for the tumor and the organ at risk, and a fourth display area 5214 that displays the cumulative value at any location of the tumor or the organ at risk.

[0048] Figure 6 shows an example of the first display area 5211. The horizontal axis in Figure 6 represents the fractions included in the treatment plan, and the vertical axis represents "D95". In Figure 6, the treatment plan progresses from left to right. As shown in Figure 6, the first display area 5211 displays the planned value A1 of "D95" planned during the treatment plan for the tumor, the actual value A2 of "D95", and the regression line A3 of the actual value A3 of "D95".

[0049] In the following explanation, "planned value" refers to the indicator calculated during treatment planning. "Actual value" includes indicators calculated during past fraction executions and predicted values ​​calculated using the pre-treatment contour for the target fraction.

[0050] By checking the planned value A1, the operator can confirm the change in the tumor's "D95" as planned during treatment planning. Furthermore, by checking the actual value A2, the operator can understand the change in the tumor's "D95" when the target fraction is executed according to the treatment plan. Additionally, by checking the regression line A3, the operator can understand the predicted value of the tumor's "D95" when the treatment plan is completed according to the treatment plan. By checking each graph in the first display area 5211, the operator can predict whether a sufficient amount of radiation will be delivered to the tumor if the treatment plan is not changed, and effectively determine whether or not the treatment plan needs to be modified.

[0051] Figure 7 shows an example of the second display area 5212. The horizontal axis of Figure 7 shows the fractions included in the treatment plan, and the vertical axis shows the average value of "V50". The average value of "V50" for each fraction is the "V50" at the completion of that fraction divided by the sum of the number of fractions in that fraction and past fractions. In Figure 7, the treatment plan progresses from left to right. As shown in Figure 7, the second display area 5212 displays the actual value of "V50" B1, the regression line B2 of the actual value of "V50", and a guide B3 representing predetermined dose constraints for a specific risk organ.

[0052] By checking the actual value B1, the operator can understand the change in "V50" when the target fraction is executed according to the treatment plan. Furthermore, by checking the regression line B2, the operator can understand the predicted value of "V50" for the organ at risk when the treatment plan is completed according to the treatment plan. Additionally, by comparing the actual value B1, the regression line B2, and the guide B3, the operator can easily determine whether the average value of "V50" for the organ at risk satisfies the dose constraint. Furthermore, by checking each graph in the second display area 5212, the operator can predict whether the radiation administered to the organ at risk will be suppressed if the treatment plan is not changed, and effectively determine whether or not the treatment plan needs to be modified.

[0053] Figure 8 shows an example of the third display area 5213. As shown in Figure 8, the third display area 5213 displays the dose distribution C1 of the tumor and the dose distribution C2 of the organs at risk. In dose distributions C1 and C2, each location is displayed with a color and intensity corresponding to the cumulative value. For example, by using a color map for dose distributions C1 and C2, it is possible to display how much radiation was irradiated to which area. In addition, areas where the cumulative value exceeds a specified value may be highlighted. For example, areas where the cumulative value exceeds the dose limit may be displayed in an easily identifiable color such as red.

[0054] In the dose distributions C1 and C2 of the third display area 5213, when the operator specifies any location of a tumor or organ at risk, the fourth display area 5214 displays a graph showing the change in cumulative value over time at the specified location. Figure 9 shows an example of the fourth display area 5214 displayed when location P is selected in the dose distribution C2 of Figure 8. The horizontal axis of Figure 9 shows the fractions included in the treatment plan, and the vertical axis of Figure 9 shows the cumulative value of the radiation dose. In Figure 9, the treatment plan progresses from left to right. As shown in Figure 9, the fourth display area 5214 displays the actual cumulative value D1, the regression line D2 of the actual cumulative value, and a predetermined guide D3 based on dose constraints for the specified location P.

[0055] By checking the actual value D1, the operator can understand the predicted cumulative value that will accumulate at the selected location if the target fraction is executed according to the treatment plan. Furthermore, by checking the regression line D2, the operator can understand the predicted cumulative value that will accumulate at the selected location if the treatment plan is completed according to the treatment plan. Additionally, by comparing the actual value D1, the regression line D2, and the guide D3, the operator can easily determine whether the cumulative value at the selected location satisfies the dose constraints for the organ at risk. Moreover, by checking each graph in the fourth display area 5214, the operator can predict whether the radiation administered to the organ at risk will be suppressed if the treatment plan is not changed for any desired location, and effectively determine whether a modification of the treatment plan is necessary.

[0056] Once step S204 is completed, the processing circuit 55 determines whether or not to perform a replanning using the replanning function 555 (step S205). The determination of whether or not to perform a replanning is made manually, for example, by the operator's operation on the first operation button 522 or the second operation button 523. If the second operation button 523 is operated, the processing circuit 55 determines not to perform a replanning (step S205-No). In this case, the processing circuit 55 transmits the treatment plan to the radiotherapy planning support device 5 without changing the contents of the treatment plan. After that, the processing circuit 55 completes the processing of step S104, which verifies the treatment plan.

[0057] On the other hand, if an operation is performed using the first operation button 522, the processing circuit 55 determines to perform a replanning (step S205-Yes) and performs a replanning of the treatment plan using the pre-treatment contour detected from the pre-treatment image (step S206). In the replanning, the processing circuit 55 resets the irradiation conditions for each unexecuted fraction included in the treatment plan based on the pre-treatment contour, and recalculates the predicted dose index values ​​based on the reset irradiation conditions. At this time, the processing circuit 55 resets the irradiation conditions so that the dose irradiated to the area surrounded by the pre-treatment contour of the tumor satisfies the required dose, and the dose irradiated to the area surrounded by the pre-treatment contour of the risk organ satisfies the dose constraint. After that, the processing circuit 55 displays the replanned treatment plan in the plan display area 524. For example, the replanned treatment plan may display the irradiation conditions for each unexecuted fraction and the predicted values ​​of each index when using the replanned irradiation conditions.

[0058] The operator checks the plan display area 524, determines whether there are any problems with the replanned treatment plan, and selects either the first operation button 522 or the second operation button 523 depending on the determination result. If the first operation button 522 is selected, the processing circuit 55 determines that there are problems with the replanned treatment plan and repeatedly performs replanning until the second operation button 523 is selected. If the second operation button 523 is selected, the processing circuit 55 transmits the finalized treatment plan to the radiotherapy planning support device 5 and terminates the process of step S104, which verifies the treatment plan.

[0059] Returning to Figure 3, once the treatment plan verification is complete through the process in step S104, the radiotherapy planning support device 5 executes the target fraction according to the treatment plan (step S105).

[0060] Then, until all fractions included in the treatment plan are completed (step S106-No), each time an unexecuted fraction included in the treatment plan is executed as the target fraction, the processes from steps S103 to S105 are executed. At this time, each time a fraction is executed, the pre-treatment contour is extracted from the pre-treatment image, evaluation information generated based on the pre-treatment contour is displayed, and if it is determined that replanning is necessary, the treatment plan is replanned. Once all fractions included in the treatment plan are completed (step S106-Yes), the radiotherapy for one example using the radiotherapy system 1 is completed.

[0061] The following describes the effects of the radiation therapy planning support device 5 and the radiation therapy system 1 according to this embodiment. The radiotherapy planning support device 5 according to this embodiment acquires a treatment plan including irradiation conditions for the tumor and organs at risk, and pre-treatment images including the tumor and organs before treatment, and extracts the pre-treatment contour of at least one of the tumor and organs at risk from the pre-treatment images. The pre-treatment images are anatomical images generated by a medical imaging diagnostic device immediately before radiation irradiation.

[0062] Furthermore, the radiation therapy planning support device 5 calculates the cumulative value of radiation irradiated to at least one of the tumor and the organ at risk if treatment is performed according to the treatment plan on the pre-treatment contour. Specifically, it calculates the cumulative value of radiation by converting the past dose distribution of the tumor or organ at risk into a dose distribution based on the pre-treatment contour, and adding the converted dose distribution to the dose distribution when treatment is performed according to the treatment plan on the pre-treatment contour.

[0063] Furthermore, the radiotherapy planning support device 5 generates evaluation information for verifying the treatment plan based on cumulative values ​​and displays the evaluation information on the display unit. The evaluation information includes, for example, information predicting what would happen if the target fraction were executed according to the treatment plan for the pre-treatment contour. The evaluation information includes indicators for confirming the effectiveness of the treatment plan, such as "D95" for tumors and "V50" for risk organs. The evaluation information may include graphs showing the changes over time in predicted values ​​when each fraction included in the treatment plan is executed for the pre-treatment contour, as shown in Figures 6 and 7, or it may include predicted values ​​when all fractions included in the treatment plan are completed for the pre-treatment contour, or it may include information on fractions that have been executed in the past. Note that only the numerical values ​​of indicators such as "D95" and "V50" may be displayed as evaluation information.

[0064] With the above configuration, the operator can confirm the effectiveness of the treatment plan and accurately determine whether replanning is necessary by checking evaluation information that reflects the movement and deformation of tumors and organs at risk. For example, as shown in Figure 6, by checking the predicted value of "D95" for the tumor and the trend of changes in the predicted value when fractions are performed according to the treatment plan, it is possible to accurately predict whether the initially planned dose will be appropriately delivered to the tumor even if the tumor deforms. Also, as shown in Figure 7, by checking the predicted value of "V50" for organs at risk and the trend of changes in the predicted value when fractions are performed according to the treatment plan, it is possible to accurately predict whether the dose delivered to organs at risk will meet the initially planned dose constraints even if the organs at risk deform.

[0065] Furthermore, the evaluation information may include dose distributions for tumors and organs at risk, as shown in Figure 8. In addition, the dose distribution may highlight areas where the cumulative value exceeds a predetermined value. Furthermore, the evaluation information may include graphs showing the change in cumulative values ​​over time at specific locations of tumors and organs at risk, as shown in Figure 9.

[0066] With the above configuration, the operator can identify areas where the dose is locally concentrated in the organ at risk by checking the dose distribution displayed on the display device 52. Furthermore, by checking the dose at any location, it is possible to individually determine whether the dose constraints are met for each location of the organ at risk, providing information for estimating the presence or absence of adverse events and the probability of adverse events occurring. For example, by individually checking the dose at locations close to important blood vessels and the spinal cord for the organ at risk, it is possible to more accurately grasp the probability of adverse events occurring due to the dose to the organ at risk exceeding the dose constraints, and to more accurately determine whether the treatment plan needs to be revised.

[0067] Furthermore, by being able to more accurately determine whether a replanning of the treatment plan is necessary, treatment can be performed without replanning if there is no need to change the irradiation conditions. Replanning requires adjusting the irradiation conditions of the entire treatment plan, which takes time for calculations. Therefore, by omitting unnecessary replanning after taking pre-treatment images, the waiting time until the start of fractionation can be shortened, reducing the burden on the patient.

[0068] (modified version) In the above embodiment, the evaluation information described included displaying the tumor's "D95" and the risk organ's "V50" at the completion of the target fraction, as well as the dose distribution of the cumulative values ​​for the tumor and risk organ. However, it is sufficient for at least one of the above to be displayed. Furthermore, the evaluation information may display only information regarding either the tumor or the risk organ. In addition, instead of a graph showing changes over time, only numerical values ​​may be displayed, and the magnitude of the numerical values ​​may be represented by color. Moreover, the evaluation information only needs to include information about unperformed fractions that reflect the pre-treatment contour, and does not need to include information about past fractions or treatment planning.

[0069] Furthermore, the evaluation information may include dose-volume distributions of tumors or organs at risk. Figure 10 shows an example of a fifth display area 5215 where dose-volume distributions of tumors and organs at risk are displayed. The fifth display area 5215 is displayed, for example, in the evaluation information display area 521 of Figure 5, together with the first display areas 5211 to the fourth display areas 5214. The horizontal axis of Figure 10 shows the average dose, and the vertical axis of Figure 10 shows the volume percentage. The average dose is the cumulative dose value at the completion of the fraction divided by the sum of the number of fractions in question and the number of past fractions. As shown in Figure 10, the fifth display area 5215 displays the past dose-volume distribution E1 of the tumor, the dose-volume distribution E2 of the tumor when the target fraction was performed, the past dose-volume distribution E3 of organs at risk, and the dose-volume distribution E4 of organs at risk when the target fraction was performed. The past dose-volume distributions E1 and E3 may be those created during treatment planning or those created during the execution of the previous fraction.

[0070] By checking dose-volume distributions E2 and E4, the operator can determine whether appropriate treatment will be provided to the tumor or organs at risk if the target fraction is administered without changing the treatment plan. Furthermore, by comparing dose-volume distributions E1 and E2, the operator can confirm changes in the dose-volume distribution of the tumor. Additionally, by comparing dose-volume distributions E3 and E4, the operator can confirm changes in the dose-volume distribution of organs at risk. In this way, by checking dose-volume distributions E1 through E4, the operator can effectively determine whether or not a modification to the treatment plan is necessary.

[0071] Furthermore, the evaluation information may include the volume of the tumor or the organ at risk. Figure 11 shows an example of a sixth display area 5216 in which the volumes of the tumor and organs at risk are displayed. The sixth display area 5216 is displayed, for example, in the evaluation information display area 521 of Figure 5, together with the first display areas 5211 to the fourth display areas 5214. The horizontal axis of Figure 11 shows the fractions included in the treatment plan, and the vertical axis of Figure 11 shows the volume. In Figure 11, the treatment plan progresses from left to right. As shown in Figure 11, the sixth display area 5216 displays the actual volume F1 of the tumor and the actual volumes F2 to F4 of the three organs at risk (organ at risk 1 to organ at risk 3). By checking the actual volume values ​​F1 to F4, the operator can understand the changes in the volume of the tumor and each organ at risk.

[0072] According to at least one embodiment described above, it is possible to assist in determining whether or not a treatment plan needs to be revised.

[0073] While several embodiments have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be implemented in a variety of other forms, and various omissions, substitutions, modifications, and combinations of embodiments are possible without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

[0074] 1…Radiation therapy system 2…Planning image acquisition device 3…Radiation therapy planning system 4…Pre-treatment imaging device 5…Radiation therapy planning support system 6...Radiotherapy equipment 51...Storage device 52…Display equipment 521... Evaluation information display area 522, 523... Operation buttons 524...Planning display area 53…Input devices 54…Communication equipment 55…Processing circuit 551... Acquisition function 552…Contour extraction function 553... Evaluation information generation function 554…Evaluation information display function 555... Replanning function

Claims

1. A treatment plan corresponding to radiotherapy to be performed on a patient, including the radiation irradiation conditions used in the radiotherapy; and an acquisition unit that acquires a pre-treatment image obtained by imaging the patient before radiotherapy based on the treatment plan is performed. An extraction unit for extracting the contour of at least one of the tumor and the organ at risk included in the pre-treatment image, A generation unit calculates the cumulative dose of radiation irradiated to at least one of the tumor and the organ at risk corresponding to the contour extracted by the extraction unit when the radiation therapy is performed based on the treatment plan, and generates evaluation information based on the cumulative value. A display control unit that displays the aforementioned evaluation information on a display unit, A radiation therapy planning support device equipped with the following features.

2. The evaluation information includes at least one of the following: a reference value such that the ratio of the area irradiated with a dose exceeding the reference value of the radiation dose to the volume of the tumor is a predetermined value; and the ratio of the area irradiated with a dose exceeding the reference value of the radiation dose to the volume of the organ at risk. The radiotherapy planning support device according to claim 1.

3. The aforementioned evaluation information is information indicating a predicted value of the amount of radiation that will be irradiated to at least one of the tumor and the risk organ corresponding to the contour extracted by the extraction unit when radiotherapy based on the treatment plan is performed. The radiotherapy planning support device according to claim 1.

4. The predicted value includes the value obtained when radiotherapy corresponding to all fractions included in the treatment plan is completed for at least one of the tumor and the organ at risk corresponding to the contour extracted by the extraction unit, The radiotherapy planning support device according to claim 3.

5. The evaluation information includes the distribution of the dose of the radiation irradiated to the organ at risk, The radiotherapy planning support device according to claim 1.

6. The display control unit highlights, in the distribution, the region where the cumulative dose of the radiation irradiated to the organ at risk exceeds a predetermined value. The radiotherapy planning support device according to claim 5.

7. The aforementioned evaluation information is information showing the change over time in the cumulative dose of the radiation irradiated to a specific location of the organ at risk. The radiotherapy planning support device according to claim 1.

8. The evaluation information further includes past dose-volume distributions and dose-volume distributions generated based on the cumulative values. The radiotherapy planning support device according to claim 2.

9. The evaluation information further includes a graph showing the change in volume of the tumor or the organ at risk over time. The radiotherapy planning support device according to claim 2.

10. The radiotherapy planning support device further comprises a replanning unit that performs a replanning of the treatment plan using contour information extracted by the extraction unit. The radiotherapy planning support device according to claim 1.

11. The aforementioned pre-treatment images are anatomical images generated by a medical imaging device immediately before radiation exposure. The radiotherapy planning support device according to claim 1.

12. The irradiation conditions include the region to be irradiated with radiation and the dose of radiation. The radiotherapy planning support device according to claim 1.

13. A treatment plan corresponding to radiotherapy to be performed on a patient, including the radiation irradiation conditions used in the radiotherapy; and a step of acquiring a pre-treatment image obtained by imaging the patient before radiotherapy based on the treatment plan is performed. The steps include extracting the contour of at least one of the tumor and the organ at risk included in the pre-treatment image, The steps include: calculating the cumulative dose of radiation irradiated to at least one of the tumor and the organ at risk corresponding to the extracted contour when the radiation therapy is performed based on the treatment plan, and generating evaluation information based on the cumulative value; The steps include displaying the aforementioned evaluation information, A method for supporting radiation therapy planning, comprising the following features.

14. A radiotherapy planning support device according to claim 1, A radiotherapy device that performs the radiotherapy on the patient based on a treatment plan generated by the radiotherapy planning support device, It has, The radiotherapy planning support device includes a generation unit that generates a second treatment plan different from the first treatment plan, based on contour information extracted by the extraction unit, The radiotherapy apparatus performs radiotherapy corresponding to the second treatment plan when an instruction to generate the second treatment plan is input to the generation unit, and performs radiotherapy corresponding to the first treatment plan when no instruction to generate the second treatment plan is input to the generation unit. Radiation therapy system.

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