Treatment planning device and treatment planning method

Abstract

To appropriately develop a treatment plan for radiation therapy while suppressing the worsening of skin diseases. [Solution] The treatment planning device according to the embodiment includes an identification unit that identifies a skin disease area on the skin of a patient receiving radiation therapy, a treatment planning unit that formulates a treatment plan for performing the radiation therapy, the treatment plan which suppresses the radiation exposure of the skin disease area, and an output unit that outputs information indicating the amount of radiation exposure the patient would receive if the radiation therapy were performed according to the treatment plan.

Description

Technical Field

[0001] The embodiments disclosed in this specification and the drawings relate to a treatment planning apparatus and a treatment planning method.

Background Art

[0002] In order to perform radiation therapy, usually, first, medical images are taken, and a treatment plan is formulated based on the medical images. Thereafter, depending on the case, radiation therapy may be performed dozens of times in some cases.

[0003] Specifically, when irradiated with radiation, normal tissues recover faster than tumors, and by utilizing this difference in recovery rate, damage can be inflicted on tumors for treatment. In order to perform radiation therapy utilizing this difference in recovery rate, it is necessary to repeatedly perform radiation therapy while setting a time interval for waiting for the recovery of normal tissues.

[0004] Here, skin diseases may occur on the skin of patients targeted for radiation therapy due to various factors. Also, skin diseases may occur due to the skin being irradiated with radiation in radiation therapy. Although there is a possibility that skin diseases may worsen due to radiation irradiation, usually, treatment of tumors and reduction of the exposure dose of organs at risk (OAR) are prioritized, and skin diseases are often dealt with by symptomatic treatments such as skin care.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

[0006] One of the problems that the embodiments disclosed in this specification and drawings aim to solve is to suppress the worsening of skin diseases while formulating an appropriate treatment plan. 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]

[0007] The treatment planning device according to this embodiment includes an identification unit that identifies a skin disease area on the skin of a patient receiving radiation therapy, a treatment planning unit that formulates a treatment plan for performing the radiation therapy, the treatment plan which suppresses the radiation exposure of the skin disease area, and an output unit that outputs information indicating the amount of radiation exposure the patient would receive if the radiation therapy were performed according to the treatment plan. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a block diagram showing an example of a radiotherapy system according to the first embodiment. [Figure 2] Figure 2 is a block diagram showing an example of the configuration of a treatment planning device according to the first embodiment. [Figure 3] Figure 3 shows an overview of the processing of the treatment planning device according to the first embodiment. [Figure 4] Figure 4 shows an example of the region identification process according to the first embodiment. [Figure 5] Figure 5 shows an example of a treatment plan according to the first embodiment. [Figure 6] Figure 6 shows an example of a treatment plan according to the first embodiment. [Figure 7] Figure 7 shows an example of a display according to the first embodiment. [Figure 8A]Figure 8A shows an example of a display according to the first embodiment. [Figure 8B] Figure 8B shows an example of a display according to the first embodiment. [Figure 9] Figure 9 is a flowchart illustrating the sequence of processes of the treatment planning device according to the first embodiment. [Modes for carrying out the invention]

[0009] The embodiments of the treatment planning device and treatment planning method will be described in detail below with reference to the attached drawings.

[0010] (First embodiment) In the first embodiment, the radiotherapy system 1 shown in Figure 1 will be described as an example. The radiotherapy system 1 includes a medical imaging diagnostic device 10, a treatment planning device 20, and a radiotherapy device 30. The medical imaging diagnostic device 10, the treatment planning device 20, and the radiotherapy device 30 are interconnected via a network NW. Note that the configuration shown in Figure 1 is merely an example, and various devices and systems not shown can also be included in the radiotherapy system 1.

[0011] The medical imaging diagnostic device 10 is a device that acquires medical images used in formulating treatment plans. Hereinafter, medical images used in formulating treatment plans will also be referred to as treatment planning images. The type of medical imaging diagnostic device 10 is not limited, but examples include X-ray CT (Computed Tomography) devices, MRI (Magnetic Resonance Imaging) devices, PET (Positron Emission Tomography) devices, SPECT (Single Photon Emission Computed Tomography) devices, X-ray diagnostic devices, and ultrasound diagnostic devices.

[0012] The treatment planning image is typically a three-dimensional image. The treatment planning image may also be a plurality of three-dimensional images collected over time. Such a time-series of three-dimensional images is also referred to as a four-dimensional image.

[0013] The treatment planning device 20 is a device that formulates a treatment plan for performing radiation therapy using the treatment planning image collected by the medical imaging device 10. The treatment plan includes, for example, irradiation parameters such as the irradiation angle of the radiation irradiated during radiation therapy, the dose for each irradiation angle, the shape of the irradiation field, and the number of irradiations. The treatment plan formulated by the treatment planning device 20 is transmitted to the radiation therapy device 30.

[0014] Here, the treatment planning device 20 identifies the skin disease area on the skin of the patient receiving radiation therapy, formulates a treatment plan that suppresses the exposure dose of the identified skin disease area, and outputs information indicating the exposure dose that occurs when radiation therapy is performed according to the formulated treatment plan, thereby appropriately formulating the treatment plan for radiation therapy while suppressing the exacerbation of the skin disease. Details of this point will be described later.

[0015] The radiation therapy device 30 performs radiation therapy according to the treatment plan. The specific configuration of the radiation therapy device 30 is not particularly limited. For example, the type of radiation used by the radiation therapy device 30 for radiation therapy may be any of electron beams, X-rays, gamma rays, proton beams, and heavy particle beams. Note that the type of radiation is an example of the irradiation parameter.

[0016] The radiation therapy system 1 may further include a radiation therapy information system (not shown). The radiation therapy information system is a system that records and manages various information related to radiation therapy. For example, the radiation therapy information system records and manages various information related to the progress of treatment, such as treatment plans, performance information (irradiation history), various reports, and records of the patient's condition, for each patient. When the radiation therapy information system is provided, the treatment plan formulated by the treatment planning device 20 is transmitted to the radiation therapy device 30 via the radiation therapy information system.

[0017] The radiation therapy system 1 may further include a medical image management system (PACS: Picture Archiving and Communication System) not shown in the drawings. The medical image management system is a system that records and manages a plurality of medical images including treatment planning images. When the medical image management system is provided, the treatment planning images collected by the medical image diagnostic device 10 are transmitted to the treatment planning device 20 via the medical image management system.

[0018] Next, a configuration example of the treatment planning device 20 will be described using FIG. 2. For example, as shown in FIG. 2, the treatment planning device 20 includes a communication interface 21, an input interface 22, a display 23, a memory 24, and a processing circuit 25.

[0019] The communication interface 21 controls the transmission and communication of various data transmitted and received between the treatment planning device 20 and other devices and systems connected via the network NW. Specifically, the communication interface 21 is connected to the processing circuit 25, outputs the data received from other devices and systems to the processing circuit 25, or transmits the data output from the processing circuit 25 to other devices and systems. For example, the communication interface 21 is realized by a network card, a network adapter, a NIC (Network Interface Controller), or the like.

[0020] The input interface 22 receives various input operations from the user of the treatment planning device 20, converts the received input operations into electrical signals, and outputs them to the processing circuit 25. For example, the input interface 22 can be implemented using a mouse, keyboard, trackball, switch, button, joystick, touchpad for input operations by touching the operating surface, touchscreen with an integrated display screen and touchpad, non-contact input circuit using optical sensors, voice input circuit, etc. The input interface 22 may also consist of the treatment planning device 20 main unit and a tablet terminal capable of wireless communication. Furthermore, the input interface 22 may be a circuit that receives input operations from the user via motion capture. For example, the input interface 22 can receive the user's body movements and gaze as input operations by processing signals acquired via a tracker and images collected about the user. Moreover, the input interface 22 is not limited to those equipped with physical operating components 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 treatment planning device 20, and outputs this electrical signal to the processing circuit 25, is also included as an example of an input interface 22.

[0021] The display 23 displays various types of information. For example, the display 23 displays a GUI (Graphical User Interface) for receiving various instructions and settings from the user via the input interface 22. The display 23 also displays treatment planning images captured by the medical imaging diagnostic device 10, the treatment plan formulated based on the treatment planning images, and the amount of radiation exposure the patient would receive if radiation therapy were performed according to the treatment plan. Furthermore, as will be described later, the display 23 displays information based on location information and biological information. For example, the display 23 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 23 may be a desktop type, or it may be composed of the treatment planning device 20 main unit and a tablet terminal that can communicate wirelessly with it.

[0022] The treatment planning device 20 may also include a projector in place of or in addition to the display 23. The projector can project onto a screen, wall, floor, etc., under the control of the processing circuit 25. For example, the projector can also project onto any plane, object, space, etc., using projection mapping.

[0023] Memory 24 can be implemented using, for example, semiconductor memory elements such as RAM (Random Access Memory) or flash memory, a hard disk, or an optical disc. For example, it stores data received from the processing circuit 25, or reads stored data and transmits it to the processing circuit 25. Memory 24 may also be implemented using a group of servers (cloud) connected to the treatment planning device 20 via a network NW.

[0024] The processing circuit 25 includes a specific function 25a, a treatment planning function 25b, and an output function 25c. The specific function 25a is an example of a specific unit. The treatment planning function 25b is an example of a treatment planning unit. The output function 25c is an example of an output unit.

[0025] For example, the processing circuit 25 functions as the specific function 25a by reading and executing a program corresponding to the specific function 25a from the memory 24. Similarly, the processing circuit 25 functions as the treatment planning function 25b and the output function 25c by reading and executing programs corresponding to the treatment planning function 25b and the output function 25c from the memory 24. Details of the specific function 25a, the treatment planning function 25b, and the output function 25c will be described later.

[0026] In the treatment planning device 20 shown in Figure 1, each processing function is stored in memory 24 in the form of a program that can be executed by a computer. The processing circuit 25 is a processor that realizes the function corresponding to each program by reading and executing the program from memory 24. In other words, the processing circuit 25, when a program has been read, has the function corresponding to the read program.

[0027] In Figure 1, the specific function 25a, treatment planning function 25b, and output function 25c are described as being realized by a single processing circuit 25. However, the processing circuit 25 may be configured by combining multiple independent processors, with each processor executing a program to realize the functions. Furthermore, each processing function of the processing circuit 25 may be appropriately distributed or integrated across one or more processing circuits.

[0028] Furthermore, the processing circuit 25 may also implement its functions by utilizing the processor of an external device connected via a network NW. For example, the processing circuit 25 reads and executes programs corresponding to each function from the memory 24, and also utilizes a group of servers (cloud) connected to the treatment planning device 20 via a network NW as computing resources to implement the functions shown in Figure 1.

[0029] In the above explanation, the term "processor" refers to circuits such as CPUs (Central Processing Units), GPUs (Graphics Processing Units), Application Specific Integrated Circuits (ASICs), and Programmable Logic Devices (e.g., Simple Programmable Logic Devices (SPLDs), Complex Programmable Logic Devices (CPLDs), and Field Programmable Gate Arrays (FPGAs)). A processor performs its functions by reading and executing programs stored in memory.

[0030] The above describes an example of the overall configuration of the radiotherapy system 1. Under this configuration, the processing circuit 25 of the treatment planning device 20 appropriately formulates a treatment plan while suppressing the worsening of skin diseases through the processing described in detail below.

[0031] Specific function 25a identifies areas of skin disease in the skin of patients receiving radiation therapy. Examples of skin disease areas include areas of skin disease not caused by radiation from radiation therapy and areas of skin disease caused by radiation from radiation therapy. In other words, examples of skin disease areas include areas where skin disease already exists before radiation therapy begins and areas where skin disease is expected to develop as radiation therapy progresses.

[0032] Figure 3 shows an overview of the processing in the processing circuit 25. For example, the specific function 25a first acquires treatment planning images collected from the patient by the medical image diagnostic device 10 and biological information collected from the patient by the biological information acquisition device 40.

[0033] The biometric information acquisition device 40 is, for example, an optical camera or a thermographic camera, and collects images of the patient's body surface. For example, if the biometric information acquisition device 40 is an optical camera, the specific function 25a can acquire patient images taken of the patient as body surface images. The optical camera may be a component of the medical imaging diagnostic device 10 or the treatment planning device 20, a wearable camera attached to the user, or a camera installed on the ceiling or wall of the examination room.

[0034] The biological information collection device 40 may be part of the treatment planning device 20, or it may be an external device separate from the treatment planning device 20. If the biological information collection device 40 is an external device, the specific function 25a can acquire the biological information collected by the biological information collection device 40 via the network NW.

[0035] The specific function 25a identifies various regions shown in Figure 4 based on the treatment planning image and biological information. For example, the specific function 25a identifies the tumor region Rt and the OAR region Rr by displaying the treatment planning image I1 on the display 23 and accepting input from the user. Alternatively, the specific function 25a may identify the tumor region Rt and the OAR region Rr by performing image processing such as segmentation on the treatment planning image I1.

[0036] Furthermore, the identification function 25a displays the patient image I2 on the display 23 and accepts user input to identify the skin disease area Rm1. For example, the user may refer to the patient image I2 and input an operation to specify the area where an abnormality is observed. Based on the correspondence between the treatment planning image I1 and the patient image I2, the identification function 25a identifies the area on the patient image I2 specified by the user as the skin disease area Rm1 in the treatment planning image I1.

[0037] The correspondence between the treatment planning image I1 and the patient image I2 can be determined using known methods. For example, the correspondence between the treatment planning image I1 and the patient image I2 can be determined by performing registration (alignment) between the images. Alternatively, by acquiring the patient image I2 simultaneously with the treatment planning image I1, the treatment planning image I1 and the patient image I2 can be associated with the same coordinate system.

[0038] The skin disease area Rm1 is the area where skin disease has developed before radiation therapy begins. The causes of such skin disease are varied, but examples include side effects of treatments such as drug therapy, or pressure ulcers resulting from prolonged bed rest. Furthermore, skin disease may develop due to illnesses or injuries unrelated to the tumor being treated. For example, dermatitis may develop due to pre-existing conditions such as atopic dermatitis.

[0039] An example of identifying the skin disease area Rm1 by accepting user input has been described, but the embodiments are not limited to this. For example, the identification function 25a may extract the skin disease area Rm1 from the patient image I2 by image processing and identify the skin disease area Rm1 on the treatment planning image I1 based on the correspondence between the treatment planning image I1 and the patient image I2.

[0040] Furthermore, while an example of identifying the skin disease area Rm1 based on the patient image I2 has been described, the embodiments are not limited to this. For example, the user can specify the skin disease area reported by the patient during the medical interview on the treatment planning image I1. Alternatively, the user can directly visually inspect the patient and specify the area where abnormalities are observed on the treatment planning image I1. In addition, the identification function 25a may identify the skin disease area Rm1 by accepting the specification of an area on a general-purpose human body model or by accepting the input of text indicating the area (e.g., "skin on the right flank") instead of specifying an area on the image.

[0041] As explained above, the specific function 25a identifies the skin disease area Rm1, where a skin disease has already occurred, at the treatment planning stage. Skin disease area Rm1 is an example of the first skin disease area. The treatment planning function 25b then formulates a treatment plan that suppresses the radiation exposure to skin disease area Rm1. For example, the treatment planning function 25b sets the irradiation angle so that skin disease area Rm1 is not included in the radiation path.

[0042] Furthermore, the treatment planning function 25b divides the multiple radiation therapy sessions into treatment groups and formulates a treatment plan for each divided treatment. Hereafter, the total number of radiation therapy sessions will also be referred to as "N". For example, if "N=30", the treatment planning function 25b formulates treatment plans such that the irradiation angle and other parameters differ for the first 15 treatments and the 16th to 30th treatments. This distributes the areas of normal tissue, including the skin, that receive radiation, thereby reducing the side effects of radiation therapy.

[0043] Hereafter, when the total number of radiation therapies "N" is divided, the treatment performed first will be referred to as the first treatment, and the treatment performed later will be referred to as the second treatment. Furthermore, the treatment plan formulated for the first treatment will be referred to as the first treatment plan, and the treatment plan formulated for the second treatment will be referred to as the second treatment plan.

[0044] Furthermore, the number of divisions when dividing the total number of radiation therapy sessions "N" may be "3" or more. For example, radiation therapy consisting of "30" sessions may be divided into three parts, and treatment plans may be formulated for each of the three parts: treatments 1 through 10, treatments 11 through 20, and treatments 21 through 30. In this case, if treatments 1 through 10 are designated as the first treatment, then treatments 11 through 20 and treatments 21 through 30 will constitute the second treatment. Similarly, if treatments 11 through 20 are designated as the first treatment, then treatments 21 through 30 will constitute the second treatment.

[0045] In the treatment plan, it is anticipated that skin diseases such as radiation dermatitis may occur in the skin area included in the radiation irradiation zone. Therefore, specific function 25a identifies the area irradiated with radiation in the first treatment as the skin disease area. This skin disease area will also be referred to as the second skin disease area. Furthermore, treatment planning function 25b formulates a second treatment plan so as to suppress the radiation exposure of the second skin disease area in the second treatment.

[0046] An example of a treatment plan that takes into account a second skin disease area is shown in Figure 5. As shown in Figure 5, the first and second treatment plans are formulated so that the irradiation angles differ from each other, assuming that they pass through the tumor area Rt. Specifically, the specific function 25a identifies the area to be irradiated in the first treatment as the skin disease area Rm2 based on the irradiation angle in the first treatment plan. The treatment planning function 25b then sets the irradiation angle in the second treatment plan so that the radiation exposure to the skin disease area Rm2 is suppressed.

[0047] Here, by setting the angle difference θ1 between the irradiation angle in the first treatment plan and the irradiation angle in the second treatment plan to be sufficiently large (for example, by setting it to about 90°), it is possible to bring the exposure dose to the skin disease area Rm2 in the second treatment close to zero. However, the angle difference θ1 cannot be set freely. Specifically, it is not appropriate to set an irradiation angle such that the dose irradiated to the tumor area Rt becomes insufficient due to a large distance from the body surface to the tumor area Rt, or the presence of high-density areas such as bone in the irradiation path. It is also not appropriate to set an irradiation angle such that the exposure dose to the OAR area Rr becomes large. Under these limitations, the treatment planning function 25b sets the irradiation angle in the second treatment plan so that exposure to the skin disease area Rm2 does not occur, or the exposure dose to the skin disease area Rm2 is reduced.

[0048] Another example of a treatment plan is shown in Figure 6. In Figure 6, the total number of radiation therapy sessions "N" is divided into three parts, and treatment plans A1, A2, and A3 are formulated for each part.

[0049] First, as mentioned above, the specific function 25a identifies the skin disease area Rm1. The treatment planning function 25b sets the irradiation angle in treatment plan A1 so that the radiation exposure to the skin disease area Rm1 is reduced. Furthermore, the specific function 25a identifies the area to be irradiated in treatment plan A1, and the treatment planning function 25b sets the irradiation angle in treatment plan A2 so that the radiation exposure to that area is reduced. Furthermore, the specific function 25a identifies the area to be irradiated in treatment plan A2, and the treatment planning function 25b sets the irradiation angle in treatment plan A3 so that the radiation exposure to that area is reduced.

[0050] As shown in Figure 6, when radiation is delivered at the irradiation angle in treatment plan A3, a portion of the OAR region Rr is included in the irradiation path. Naturally, it is preferable to minimize the exposure to the OAR region Rr, but from an overall evaluation, there may be cases where a treatment plan like the one shown in Figure 6 is preferable. For example, although exposure to the OAR region Rr occurs in Figure 6, depending on the irradiation parameters such as dose and number of irradiations, it may be below the permissible dose. Also, there may be cases where treatment is interrupted due to the high severity of the patient's skin disease, making it highly important to suppress the exposure to the skin disease area.

[0051] Therefore, the treatment planning device 20 outputs information indicating the amount of radiation exposure the patient would receive if radiation therapy were performed according to the treatment plan formulated by the treatment planning function 25b, thereby enabling the appropriate formulation of a radiation therapy treatment plan while suppressing the worsening of skin diseases.

[0052] For example, output function 25c outputs a dose-volume histogram (DVH) as information indicating the patient's radiation exposure, as shown in Figure 7. Figure 7 is a diagram showing an example of the display according to the first embodiment.

[0053] The output function 25c can provide the DVH to the user via the output device shown in Figure 3. The output device shown in Figure 3 is, for example, the display 23 of the treatment planning device 20. That is, the output function 25c can display the DVH on the display 23. To give another example, the output device shown in Figure 3 is the display 50 of a device other than the treatment planning device 20. Examples of the display 50 include the display of the medical imaging diagnostic device 10 and an image display terminal device (viewer). In this case, the output function 25c transmits the DVH to the other device via the network NW and displays it on the display 50.

[0054] Figure 7 shows histograms H1, H2, H3, and H4 in the DVH section. Histogram H1 is a histogram showing the exposure to the OAR region Rr when radiotherapy is performed according to treatment plan A1 in Figure 6. More specifically, histogram H1 shows the exposure to the OAR region Rr when "N" radiotherapy sessions are performed according to treatment plan A1 without dividing the total number of radiotherapy sessions "N". In this case, histogram H1 is determined according to the irradiation angle and dose, regardless of how many of the total number "N" sessions are performed according to treatment plan A1.

[0055] Similarly, histogram H2 is a histogram showing the radiation dose to the OAR region Rr that would occur if radiotherapy were performed according to treatment plan A2. Similarly, histogram H3 is a histogram showing the radiation dose to the OAR region Rr that would occur if radiotherapy were performed according to treatment plan A3.

[0056] Histogram H4 is a histogram showing the dose delivered to the tumor area Rt when radiotherapy is performed according to treatment plans A1 to A3. For example, if "N=30" and each of treatment plans A1 to A3 is performed "10 times", histogram H4 shows the sum of the dose delivered to the tumor area Rt in the "10 times" of treatment according to treatment plan A1, the dose delivered to the tumor area Rt in the "10 times" of treatment according to treatment plan A2, and the dose delivered to the tumor area Rt in the "10 times" of treatment according to treatment plan A3. By referring to histogram H4, it can be seen, for example, that radiation doses exceeding "50 Gy" are delivered to almost the entire tumor area Rt, and radiation doses exceeding "60 Gy" are delivered to approximately "80%" of the area.

[0057] By referring to the DVH in Figure 7, the user can determine whether it is possible to treat the tumor by irradiating the tumor area with a sufficient dose, and whether the exposure in the OAR area is within an acceptable range. For example, the user can consider whether the exposure in the OAR area is acceptable by comparing it with the acceptable levels shown in Figure 7, and modify the treatment plan if necessary. The acceptable levels may be set by the user or may be preset depending on the site.

[0058] In the example shown in Figure 7, histograms H1 and H2 are below the acceptable level, but histogram H3 is above the acceptable level. In other words, if "N" sessions of radiotherapy are performed according to treatment plan A3, exposure exceeding the acceptable level will occur in the OAR region. Whether or not this is acceptable is left to the user's judgment.

[0059] If a user, referring to the DVH in Figure 7, determines that the exposure in the OAR region is unacceptable, the treatment plan is modified. For example, the user performs an input operation via the input interface 22 to modify the treatment plan. In this case, the treatment planning function 25b modifies the treatment plan to suppress the exposure in the OAR region, and the output function 25c outputs the DVH if radiotherapy is performed according to the modified treatment plan. Alternatively, the user may manually modify the treatment plan via the input interface 22.

[0060] For example, in the examples shown in Figures 6 and 7, the exposure dose in the OAR region can be reduced by decreasing the angle difference θ2 between the irradiation angle in treatment plan A1 and the irradiation angle in treatment plan A2, and the angle difference θ3 between the irradiation angle in treatment plan A2 and the irradiation angle in treatment plan A3. It is also possible to reduce the exposure dose in the OAR region by changing the number of divisions. For example, by omitting treatment in treatment plan A3, where the exposure dose in the OAR region is large, and dividing the "N" radiation therapy sessions into two parts, treatment plan A1 and treatment plan A2, the exposure dose in the OAR region can be reduced.

[0061] It is conceivable that a user referring to the DVH in Figure 7 might determine that the exposure in the OAR region is acceptable. That is, since radiotherapy is performed in segments, the number of radiotherapy sessions performed according to treatment plan A3 will be less than "N", and the exposure in the OAR region will be smaller than that shown in histogram H3. For example, if "N=30" and treatments A1 to A3 are each performed "10 times", the exposure in the OAR region will be approximately the average of histograms H1 to H3, which may be below the acceptable level.

[0062] Furthermore, it is conceivable that users who refer to the DVH in Figure 7 may, while acknowledging the high radiation exposure in the OAR region, decide not to modify the treatment plan in order to prioritize suppressing the worsening of skin diseases. For example, if the radiation exposure in the OAR region is reduced by decreasing the angle difference θ2 or θ3 or reducing the number of divisions, more radiation will be irradiated to the same skin area, potentially worsening skin diseases such as radiodermatitis. Worsening skin diseases cause stress to the patient due to pain and itching, and also affect the efficiency of radiation therapy. In other words, if a skin disease becomes severe, the patient may move their body due to pain and itching during radiation therapy, which may reduce the efficiency of the treatment. Moreover, if the severity of the skin disease increases, it may be necessary to interrupt radiation therapy. For these reasons, it is conceivable that there will be cases where suppressing the worsening of skin diseases is prioritized over reducing the radiation exposure in the OAR region.

[0063] Furthermore, the extent to which radiation therapy will increase the severity of skin diseases can be generally estimated at the stage of formulating the treatment plan. For example, the correspondence between the grades indicating the severity of radiation dermatitis and the doses that are the benchmark for the onset of radiation dermatitis at each grade is generally known. Based on such correspondences, output function 25c may estimate the grade of severity of radiation dermatitis that will occur on the patient's skin when radiation therapy is performed and notify the user.

[0064] Note that while Figure 7 shows the tolerance line as a linear graph, this can be changed as needed. For example, the tolerance line may be set as any function other than a linear function. Alternatively, the tolerance line may simply be set as a dose value. Furthermore, the tolerance line may be drawn freehand by the user on the DVH.

[0065] Furthermore, Figure 7 shows histograms H1 to H3 as histograms indicating the exposure dose in the OAR region. That is, an example has been described in which the exposure doses resulting from treatment plan A1, treatment plan A2, and treatment plan A3 are shown individually. However, the embodiment is not limited to this, and the output function 25c may output information showing the total exposure dose resulting from multiple treatment plans.

[0066] An example of outputting information showing the total radiation exposure will be explained using the DVH in Figure 8A. The DVH in Figure 8A includes histograms H1, H2, and H4. Since histograms H1, H2, and H4 are the same as those shown in Figure 7, a detailed explanation will be omitted.

[0067] In Figure 8A, the treatment plan is formulated so that for N=30, treatment plan A1 is performed 15 times and treatment plan A2 is performed 15 times. In other words, in Figure 8A, the radiation therapy is divided into two parts in a ratio of 15:15. Output function 25c displays a composite histogram, which is a combination of histogram H1 and histogram H2 based on this division ratio. In the case shown in Figure 8A, since treatment plan A1 and treatment plan A2 are performed the same number of times, the composite histogram shows the radiation exposure amount which is approximately the average of histogram H1 and histogram H2. Note that in Figure 8A, the composite histogram is displayed in addition to histogram H1 and histogram H2, but output function 25c may display only the composite histogram.

[0068] Users referring to the DVH in Figure 8A will decide whether or not to accept the exposure level in the OAR region. If not, the treatment plan will be modified. Specifically, as mentioned above, the exposure level in the OAR region can be reduced by adjusting the angle difference θ2 and the number of divisions.

[0069] Furthermore, the exposure in the OAR region can also be reduced by adjusting the proportion of treatment sessions. Specifically, in DVH in Figure 8A, histogram H2 shows a higher exposure than histogram H1. In other words, if the same number of sessions are performed, treatment plan A2 will result in a higher exposure in the OAR region than treatment plan A1. Therefore, as shown in Figure 8B, increasing the proportion of treatment plan A1 can reduce the total exposure.

[0070] For example, when referring to the DVH in Figure 8A, the user performs an input operation via the input interface 22 to modify the treatment plan. The treatment planning function 25b then formulates a treatment plan with a larger proportion of treatment plan A1 so as to reduce the radiation dose in the OAR area, and the output function 25c displays the DVH as shown in Figure 8B, which would result if radiotherapy were performed according to that treatment plan. Alternatively, the proportion of the treatment plan may be manually modified by the user via the input interface 22.

[0071] For example, if the user decides to start treatment with the treatment plan shown in DVH in Figure 8B, the first 25 radiation therapy sessions will be performed according to treatment plan A1, and the 26th to 30th radiation therapy sessions will be performed according to treatment plan A2. In other words, the treatment plan will be switched at the time the 26th radiation therapy session is performed.

[0072] As mentioned above, the timing of switching treatment plans can be determined at the stage of formulating the treatment plan, but it may also be changed as appropriate at the user's discretion during the course of radiation therapy. For example, when performing the 26th radiation therapy, if the radiation dermatitis in the skin area irradiated in the first 25 radiation therapy sessions was less severe than expected, radiation therapy may be continued according to treatment plan A1. Conversely, if the radiation dermatitis becomes more severe than expected, the treatment plan may be switched earlier than the 26th session.

[0073] Next, the flowchart in Figure 9 will be used to explain the sequence of operations of the treatment planning device 20. Figure 9 is a flowchart illustrating the sequence of operations of the treatment planning device according to the first embodiment.

[0074] Steps S11 and S12 correspond to specific function 25a. Steps S13, S14, S16, and S17 correspond to treatment planning function 25b. Step S15 corresponds to output function 25c.

[0075] When the formulation of a treatment plan begins, the processing circuit 25 first acquires medical images (treatment planning images) captured by the medical imaging diagnostic device 10 (step S11). In addition, the processing circuit 25 may acquire body surface images, such as patient images taken of the patient with an optical camera. Next, the processing circuit 25 identifies the area on the patient's skin where a skin disease has occurred (first skin disease area) based on the treatment planning images and body surface images (step S12).

[0076] Next, the processing circuit 25 formulates multiple treatment plans by dividing the radiation therapy into treatment sessions (step S13). For example, the processing circuit 25 formulates a first treatment plan for executing the first treatment so as to suppress the radiation exposure of the first skin disease area identified in step S12. Furthermore, the processing circuit 25 identifies the area to be irradiated with radiation in the first treatment as the second skin disease area and formulates a second treatment plan for executing the second treatment so as to suppress the radiation exposure of the second skin disease area.

[0077] Next, the processing circuit 25 accepts the specification of an acceptable level (step S14). The processing circuit 25 also displays the exposure amounts from the multiple treatment plans formulated in step S13 as DVH, along with the acceptable level (step S15). If an acceptable level is preset, step S14 may be omitted.

[0078] Next, the processing circuit 25 determines whether or not to modify the treatment plan based on the user's input operation referring to the DVH (step S16). If modification is to be made (affirmative in step S16), the processing circuit 25 accepts the modification of the number or ratio of divisions (step S17). For example, in the case shown in Figure 7, the exposure dose in the OAR region Rr can be reduced by modifying the number of divisions to exclude treatment plan A3 and divide it into two divisions, treatment plan A1 and treatment plan A2. Also, for example, as shown in Figures 8A and 8B, the exposure dose in the OAR region Rr can be reduced by modifying the division method to increase the proportion of treatment plans with relatively low exposure doses. Next, the processing circuit 25 proceeds back to step S15 and displays the exposure dose that would occur if radiotherapy were performed according to the modified treatment plan as the DVH.

[0079] On the other hand, if it is determined in step S16 that no modifications are necessary, the formulation of the treatment plan is completed. Subsequently, radiation therapy is performed using the radiation therapy device 30 according to the formulated treatment plan.

[0080] As described above, the identification function 25a in the first embodiment identifies the skin disease area on the skin of a patient receiving radiation therapy. The treatment planning function 25b formulates a treatment plan for performing radiation therapy, which suppresses the radiation exposure to the skin disease area. The output function 25c outputs information indicating the amount of radiation exposure the patient would receive if radiation therapy were performed according to the treatment plan. As a result, the treatment planning device 20 can formulate an appropriate treatment plan for radiation therapy while suppressing the worsening of the skin disease.

[0081] In other words, the treatment planning device 20 formulates a treatment plan so as to suppress radiation exposure in areas where skin disease has already occurred or in areas where skin disease is expected to occur as radiation therapy progresses. This suppresses the worsening of skin disease and alleviates patient stress such as pain and itching. It also improves the efficiency of radiation therapy by reducing cases where patients move their bodies due to pain or itching during radiation therapy. Furthermore, it reduces cases where radiation therapy is interrupted due to the worsening of skin disease.

[0082] Furthermore, generally speaking, a treatment plan that delivers a sufficient dose to the tumor area and reduces the exposure to the OAR area is considered appropriate. The treatment planning device 20 can ensure that a treatment plan is formulated appropriately by formulating a treatment plan that suppresses the exposure to the skin disease area and outputting information indicating the amount of exposure that would occur if radiotherapy were performed according to that treatment plan.

[0083] While we have described examples of displaying DVH (Deep Voltage Height) data indicating exposure in the OAR (Occlusive Area) region and DVH data indicating exposure in the tumor region, one of these may be omitted. For example, if there is no OAR near the tumor region, the DVH output indicating exposure in the OAR region will be omitted.

[0084] Furthermore, for example, the treatment planning function 25b formulates a treatment plan on the condition that the radiation dose in the OAR area is below an acceptable level. In this case, the output function 25c outputs only the DVH, which indicates the radiation dose in the tumor area, and the user confirms whether a sufficient dose is irradiated to the tumor area.

[0085] Furthermore, for example, the treatment planning function 25b formulates a treatment plan on the condition that a sufficient dose is irradiated to the tumor area. In this case, the output function 25c outputs only the DVH, which indicates the exposure dose in the OAR area, and the user confirms whether the exposure dose in the OAR area is acceptable.

[0086] Furthermore, while we have described examples of outputting DVH as information indicating the amount of radiation exposure, the embodiments are not limited to this. For example, the output function 25c may output information indicating the amount of radiation exposure in other forms, such as dose distribution diagrams.

[0087] Furthermore, while it has been explained so far that one irradiation angle corresponds to one treatment plan, the embodiments are not limited to this, and multiple irradiation angles may correspond to one treatment plan. In other words, the embodiments are not limited to single-field irradiation, but can also be applied to two-field irradiation, multi-field irradiation of three or more fields, motion irradiation, conformal irradiation, etc.

[0088] Each component of the apparatus according to the above embodiment is a functional concept and does not necessarily have to be physically configured as shown in the illustration. That is, the specific form of distribution and integration of each apparatus is not limited to that shown in the illustration, and all or part of it can be functionally or physically distributed and integrated in any unit according to various loads and usage conditions. Furthermore, each processing function performed by each apparatus can be implemented in whole or in any part by a CPU and a program that is analyzed and executed by the CPU, or by hardware using wired logic.

[0089] Furthermore, the treatment planning method described in the above-mentioned embodiments can be implemented by executing a pre-prepared program on a computer such as a personal computer or workstation. This program can be distributed via a network such as the Internet. Alternatively, this program can be recorded on a computer-readable non-transient recording medium such as a hard disk, flexible disk (FD), CD-ROM, MO, or DVD, and executed by reading it from the recording medium by a computer.

[0090] According to at least one embodiment described above, it is possible to suppress the worsening of skin diseases while appropriately formulating a treatment plan for radiation therapy.

[0091] 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 can be made 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]

[0092] 1: Radiation therapy system 10: Medical imaging diagnostic equipment 20: Treatment planning device 21: Communication Interface 22: Input Interface 23: Display 24: Memory 25: Processing Circuit 25a: Specific functions 25b: Treatment planning function 25c: Output function 30:Radiotherapy equipment 40: Biological Information Collection Device 50: Display

Claims

1. A specific area in the skin of a patient receiving radiation therapy to identify the area of ​​skin disease, A treatment plan for performing the aforementioned radiation therapy, comprising a treatment planning unit that formulates a treatment plan that suppresses the radiation exposure to the skin disease area, An output unit that outputs information indicating the amount of radiation exposure the patient receives when the radiation therapy is performed according to the treatment plan. A treatment planning device equipped with the following features.

2. The treatment planning device according to claim 1, wherein the output unit outputs a dose-volume histogram as information indicating the patient's radiation exposure.

3. The treatment planning device according to claim 2, wherein the output unit outputs the dose-volume histogram for at least one of the tumor to be treated by radiotherapy and the organ at risk.

4. The initial identification unit identifies the area irradiated with radiation in the first treatment, which is one of the first and second treatments obtained by dividing the radiation therapy into treatment sessions, as the skin disease area. The treatment planning device according to claim 1, wherein the treatment planning unit formulates the treatment plan so that the amount of radiation exposure to the skin disease area is suppressed in the second treatment.

5. The treatment planning unit formulates a first treatment plan for carrying out the first treatment and a second treatment plan for carrying out the second treatment. The treatment planning device according to claim 4, wherein the output unit outputs a dose-volume histogram for when the radiotherapy is performed according to the first treatment plan and a dose-volume histogram for when the radiotherapy is performed according to the second treatment plan, as information indicating the amount of radiation exposure of the patient.

6. The treatment planning unit formulates a first treatment plan for carrying out the first treatment and a second treatment plan for carrying out the second treatment. The treatment planning device according to claim 4, wherein the output unit outputs a composite histogram obtained by combining a dose-volume histogram obtained when the radiotherapy is performed according to the first treatment plan and a dose-volume histogram obtained when the radiotherapy is performed according to the second treatment plan, as information indicating the amount of radiation exposure of the patient.

7. The treatment planning device according to claim 4, wherein the treatment planning unit modifies at least one of the number of divisions and the ratio of divisions when dividing the radiotherapy into treatment sessions, based on the radiation exposure of the organs at risk.

8. The treatment planning device according to claim 1, wherein the preceding specific unit identifies an area on the patient's skin where a skin disease has occurred, as the skin disease area.

9. The treatment planning device according to claim 8, wherein the preceding identification unit identifies the area where the skin disease is occurring by receiving an operation to specify the area.

10. The treatment planning device according to claim 8, wherein the initial identification unit identifies the area where the skin disease is occurring based on the patient's body surface image.

11. The initial identification unit identifies the area on the patient's skin where a skin disease has occurred as the first skin disease area, and further identifies the area irradiated with radiation in the first treatment of the first treatment, which is obtained by dividing the radiation therapy into the number of treatment sessions, as the second skin disease area. The treatment planning device according to claim 1, wherein the treatment planning unit formulates a first treatment plan for performing the first treatment such that the exposure to the first skin disease area is suppressed, and a second treatment plan for performing the second treatment such that the exposure to the first skin disease area and the second skin disease area is suppressed.

12. In patients receiving radiation therapy, the area of ​​skin disease is identified in the skin. A treatment plan for performing the aforementioned radiotherapy, wherein a treatment plan is formulated that suppresses the amount of radiation exposure to the skin disease area, The output displays information indicating the amount of radiation exposure the patient receives when the radiation therapy is performed according to the treatment plan. A treatment plan that includes the following.

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