Neutron beam irradiation device for treatment

Abstract

Provided is a neutron beam irradiation device with which it is possible to cause a lesion located at a deeper position from the body surface to absorb a neutron beam dose sufficient for treatment, without increasing the neutron beam exposure dose of normal cells. In order to achieve the above, this neutron beam irradiation device 100 comprises: a plurality of heads 1, each of the heads having a built-in accelerator neutron source and being capable of independently emitting a neutron beam; and a control unit 3 for controlling the heads 1. The heads 1 are arranged so that the neutron beams B emitted from the respective heads 1 are directed toward a lesion C. The control unit 3 causes the neutron beams B to be emitted from the heads 1 simultaneously or at staggered timings within one neutron beam irradiation cycle.

Description

Therapeutic Neutron Irradiation Device

[0001] The present invention relates to a neutron irradiation device for irradiating a lesion such as a tumor with neutron rays for treatment.

[0002] Boron Neutron Capture Therapy (BNCT), which irradiates a lesion such as a malignant tumor with neutron rays to kill it, is known (see Non-Patent Document 1).

[0003] The advantages of BNCT include less impact on normal cells, can be used for treating tumors that have recurred after radiotherapy, has a short treatment period and less burden on patients, and can be expected to improve the quality of life (QOL) because no incision or resection is required. The treatment procedure in BNCT is as follows.

[0004] (1) Infuse a boron compound to collect boron in the lesion. (2) Irradiate neutron rays from outside the body. (3) Destroy the lesion by the radiation generated by the nuclear reaction between boron and neutrons.

[0005] As a conventional neutron irradiation device used for the above-described BNCT, those using a nuclear reactor or an accelerator as a neutron source are known. Specifically, it has a single head, and in treatment, neutron rays are irradiated once from the head to the lesion.

[0006] The emitted dose of neutron rays at this time is determined so that the neutron ray absorption dose of normal cells is at most 12 Gy - Eq.

[0007] Fig. 5 shows the neutron ray absorption dose of lesion cells according to the depth from the body surface when neutron rays are irradiated so that the neutron ray exposure dose of normal cells is at most 12 Gy - Eq.

[0008] As is clear from the figure, for example, in order to ensure a neutron ray dose absorption of 60 Gy - Eq or more required for treating many lesions, it is necessary that the lesion is at a depth of about 4 cm or less from the body surface. Therefore, for lesions in deeper locations, it is often difficult to treat them without performing surgical treatments such as incision to expose the lesion.

[0009] Guidebook on Accelerator BPA-BNCT, edited by the Japanese Society for Neutron Capture Therapy and the Japanese Society for Radiation Lesion (published on the following webpage on October 8, 2024): https: / / www.jastro.or.jp / medicalpersonnel / guideline / BPA-BNCT20200219.pdf

[0010] Therefore, the present invention has been made in view of the above problems, and its main objective is to provide a neutron irradiation device that can deliver a sufficient dose of neutrons for treatment to lesions located deeper than the body surface without increasing the neutron radiation dose to normal cells.

[0011] In other words, the neutron beam irradiation apparatus according to the present invention irradiates a lesion with neutron beams and comprises a plurality of heads, each containing an accelerator neutron source and capable of independently emitting neutron beams, and a control unit that controls each of the heads, wherein the neutron beams emitted from each head are arranged to be directed toward the lesion, and the control unit is characterized in that it emits neutron beams from each head simultaneously or at staggered timings during a single neutron beam irradiation cycle.

[0012] According to the present invention with this configuration, in a single neutron irradiation cycle, neutrons are irradiated toward the lesion from multiple heads, or in other words, neutrons are irradiated toward the lesion from different directions. Therefore, compared to the conventional method in which neutrons are irradiated toward the lesion from a single location, the neutron exposure dose to each individual normal cell is reduced.

[0013] Therefore, by setting the neutron emission rate so that the neutron radiation dose to normal cells is equivalent to that of conventional methods, neutron therapy becomes possible for lesions located deeper than the body surface.

[0014] Conversely, if the lesion remains at the same depth as before, the neutron radiation dose to normal cells can be reduced.

[0015] Furthermore, since neutron beams can be irradiated from multiple heads, it becomes possible to treat lesions over a wide area.

[0016] If the dose of neutrons administered to normal tissue in a single neutron irradiation cycle is set to less than 5 Gy-Eq, and if the neutron irradiation cycle is performed multiple times with a predetermined time interval between cycles, the number of normal cells killed by neutron exposure can be drastically reduced compared to conventional methods, and neutron therapy for lesions located deeper in the body can be made possible.

[0017] If the accelerator neutron source utilizes a deuterium-deuterium reaction, and the head further includes high-density polyethylene to slow down the neutron beam generated by the accelerator neutron source, then it becomes possible to irradiate the lesion with neutron beams at an appropriate speed and to miniaturize the device.

[0018] If the system further includes supports that allow each of the heads to move independently of each other, and the control unit adjusts the position and orientation of each head via the supports and controls the irradiation pattern of the neutron beams emitted from each head to the lesion (for example, the distance and angle from each head to the lesion, the number of cycles, the cycle interval, etc.), then the degree of freedom in the irradiation pattern of the neutron beams to the lesion increases, enabling more appropriate treatment.

[0019] As described above, as the degree of freedom in neutron beam irradiation methods increases, the diversity of these methods makes it difficult for doctors and other medical professionals to determine an appropriate irradiation method based solely on their conventional experience. To improve this, it is preferable that the control unit includes a treatment information storage unit that stores past treatment information from the neutron beam irradiation device, and an irradiation setting unit that sets the irradiation method based on the past treatment information and lesion examination information of the patient scheduled to receive treatment.

[0020] More specifically, it is desirable that the irradiation setting unit uses a machine learning model such as AI to set the irradiation mode. This is because it has advantages such as facilitating the development of the irradiation setting unit.

[0021] If the aforementioned past treatment information includes basic patient information such as age and gender for each patient who has received treatment to date, lesion examination information, and irradiation method information indicating the method of neutron beam irradiation to the lesion, then, for example, an appropriate machine learning model can be constructed.

[0022] This is a schematic overall diagram of a neutron irradiation device in one embodiment of the present invention. This is a functional block diagram of the neutron irradiation device in the same embodiment. This is a data configuration diagram showing treatment information in the same embodiment. This is a graph showing the difference in treatment effect between a conventional neutron irradiation device and the neutron therapy device of the same embodiment. This is a graph showing the relationship between the amount of neutron beam absorbed by the lesion and the amount of neutron beam exposure to normal cells in a conventional neutron irradiation device, with the depth of the lesion from the body surface on the horizontal axis.

[0023] An embodiment of the neutron irradiation apparatus according to the present invention will be described below with reference to the drawings.

[0024] The neutron beam irradiation device 100 according to this embodiment irradiates the lesion C of patient K, specifically the lesion C, with neutron beam B. As shown in Figures 1 and 2, it comprises a plurality of heads 1 that emit neutron beam B, a support body 2 that supports each head 1 so that it can move independently of each other, and a control unit 3 that controls each head 1.

[0025] Each part will be described in detail.

[0026] The head 1 is equipped with an accelerator neutron source and a decelerator (not shown). The accelerator neutron source is also called a DD Fusion Neutron Source, which utilizes a deuterium-deuterium reaction. Specifically, deuterium ions generated in a plasma ionization section are accelerated in an acceleration section and collided with a deuterium-containing titanium target, generating 2.45 MeV deuterium fusion neutrons through the resulting nuclear fusion reaction. The decelerator is made of high-density polyethylene with a thickness of 3 cm to 5 cm and decelerates the neutrons generated in the accelerator neutron source, ejecting them to the outside of the head 1.

[0027] The support body 2 in this example is equipped with a robot arm having six degrees of freedom, and the same number of support bodies are provided as there are heads 1. The support body 2 may have fewer than six degrees of freedom, and is not limited to a robot arm; it may also utilize a slider mechanism or the like.

[0028] Physically speaking, the control unit 3 is primarily a computer consisting of a CPU, internal memory, I / O ports, etc., with drivers and external memory added to it. Functionally speaking, the control unit 3 performs functions such as a reception unit, a treatment information storage unit 32, an irradiation setting unit 31, and a model construction unit through the cooperation of the CPU and its peripheral devices based on a predetermined program stored in the memory.

[0029] Furthermore, this control unit 3 does not need to be a single physical unit; it may be configured by connecting multiple devices in a way that allows them to communicate with each other.

[0030] Next, we will describe the various parts of the control unit 3.

[0031] The treatment information storage unit 32 is set in a predetermined area of ​​the memory, and stores treatment information from past treatments performed by the neutron beam irradiation device 100, namely, as shown in Figure 3, patient basic information, lesion examination information, and irradiation pattern information, separated for each patient K and each treatment.

[0032] As shown in the figure, basic patient information includes all or part of the age, sex, height, weight, blood type, and past medical history of patient K who is receiving or has received neutron irradiation treatment.

[0033] Lesion examination information refers to information about lesion C examined by CT, MRI, blood tests, etc., and includes all or part of the lesion image, lesion type, lesion location, lesion size, and marker values. This lesion examination information includes a pair of records: one before neutron irradiation (pre-treatment lesion examination information) and one after irradiation (post-treatment lesion examination information).

[0034] Irradiation pattern information includes the number of neutron irradiation cycles performed in a single treatment, the time interval between neutron irradiation cycles, the distance and angular interval from each head 1 to the lesion C in each neutron irradiation cycle, and all or part of the emission intensity and emission time of the neutron beam B emitted from each head 1 in each neutron irradiation cycle. One neutron irradiation cycle (hereinafter also referred to as one fraction) is a cycle in which neutron beam B is irradiated from each head 1 to the lesion C once simultaneously or once at a time with a time delay. Multiple fractions are performed in a single treatment.

[0035] Of the information described above, the patient's basic information and lesion examination information are input to or transmitted to the control unit 3 from an input device such as a keyboard, mouse, or touch panel, or from an external device such as an electronic medical record system, and stored in the treatment information storage unit 32. In addition, the irradiation pattern information, which is set in the irradiation setting unit 31 (described later), is stored in the treatment information storage unit 32.

[0036] The irradiation setting unit 31 includes a setting unit main body 31a that sets the irradiation pattern of the neutron beam B for the treatment to be performed on patient K and outputs it as irradiation pattern information, and a command signal output unit 31b that converts the irradiation pattern information output by the setting unit main body 31a to generate a command signal so that the neutron beam B is irradiated in accordance with the irradiation pattern information, and transmits the command signal to local controllers (not shown) provided on each head 1 and each support 2.

[0037] The setting unit body 31a calculates the irradiation pattern information by processing the patient's basic information and lesion examination information according to an internal algorithm when these are input. In this embodiment, the calculation is performed using a machine learning model. This machine learning model, for example, utilizes AI and is configured to learn the internal algorithm based on past treatment information stored in the treatment information storage unit 32.

[0038] Next, I will explain the operation of this neutron beam irradiation device 100 in relation to treatment.

[0039] First, when the patient basic information and lesion examination information (pre-treatment lesion examination information) of the patient K to be treated are input, the setting unit main body 31a receives this and refers to the past treatment information stored in the treatment information storage unit 32, and calculates irradiation mode information estimated to be optimal based on the internal algorithm of the machine learning model.

[0040] Next, the command signal output unit 31b converts the irradiation mode information into a command signal interpretable by the local controller and outputs it to each head 1 and each support 2.

[0041] The local controllers of each head 1 and each support 2 that receive this command signal control the respective heads 1 and supports 2, and irradiate the lesion C of the patient K placed on the treatment table 4 with neutron beams B in the irradiation mode set by the machine learning model.

[0042] In this embodiment, the fractionation is performed multiple times (here, 6 times) at intervals of 0.5 days to several days.

[0043] Here, the total neutron beam dose emitted from all the heads 1 in one fractionation is set such that the absorbed dose (administered dose) in normal cells is less than 5 Gy - Eq (for example, 5 Gy - Eq). Also, in the same fractionation, the timing of the neutron beams B emitted from each head 1 is simultaneous, but the timing may be shifted.

[0044] Thus, when one treatment, that is, multiple fractionations are completed, after a certain period, the patient K is examined. This examination result is stored in the treatment information storage unit 32 in association with the irradiation mode information, patient basic information, and pre-treatment lesion examination information in this treatment as post-treatment lesion examination information.

[0045] Also, when the treatment information is newly added to the treatment information storage unit 32 in this way, the machine learning model further refers to the new treatment information and modifies its internal algorithm.

[0046] Fig. 4 shows an example of the difference in the therapeutic effects between a conventional neutron irradiation device and the neutron irradiation device 100 of the present embodiment. According to the treatment by the neutron irradiation device 100 of the present embodiment, it can be seen that the amount of dead normal cells has decreased significantly, even though the tumor is irradiated with the same amount of neutron rays as in the conventional case.

[0047] Thus, according to the neutron irradiation device described above, the following effects can be achieved. Even for a tumor deep in the body that requires combined use with an initial surgery or laparotomy in the conventional device, it can be treated without surgery.

[0048] The conventional device could not treat tumors that spread widely, such as gliomas, but the neutron irradiation device 100 of the present embodiment can treat them.

[0049] Since the dose per fraction can be reduced, the neutron shielding can be made thinner. Therefore, large-scale facilities for such shielding, such as newly constructing a dedicated hospital building, are not required, and it can also be installed in an existing radiotherapy room (x-ray therapy room).

[0050] Note that the present invention is not limited to the above embodiment.

[0051] For example, the irradiation setting unit may set the irradiation mode according to a predetermined algorithm without relying on machine learning, or may be configured to set or modify the irradiation mode according to the input of a doctor or the like.

[0052] Needless to say, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist thereof.

[0053] According to this neutron irradiation device, in one neutron irradiation cycle, neutron rays are irradiated from a plurality of heads toward the tumor, that is, neutron rays are irradiated toward the tumor from different directions. Therefore, compared with the conventional method of irradiating neutron rays from one location toward the tumor, the neutron exposure dose in each normal cell is reduced.

[0054] 100... Neutron beam irradiation device 1... Head 2... Support 3... Control unit 31... Irradiation setting unit 32... Treatment information storage unit B... Neutron beam C... Lesion

Claims

1. A neutron irradiation device for irradiating a lesion with neutron beams, comprising: a plurality of heads, each containing an accelerator neutron source and capable of independently emitting neutron beams; and a control unit for controlling each of the heads, wherein the neutron beams emitted from each head are positioned toward the lesion; and the control unit is characterized in that it emits neutron beams from each head simultaneously or at staggered timings during a single neutron irradiation cycle.

2. The neutron irradiation apparatus according to claim 1, characterized in that the dose of neutrons administered to normal tissue in a single neutron irradiation cycle is set to less than 5 Gy-Eq, and the neutron irradiation cycle is performed multiple times with a predetermined time interval between each cycle.

3. The neutron irradiation apparatus according to claim 1, characterized in that the accelerator neutron source utilizes a deuterium-deuterium reaction, and the head further comprises high-density polyethylene for slowing down the neutron beam generated by the accelerator neutron source.

4. The neutron beam irradiation apparatus according to claim 1, further comprising a support body that independently supports each of the heads so as to be movable, wherein the control unit adjusts the position and orientation of each head via the support body and controls the irradiation manner of the neutron beams emitted from each head to the lesion.

5. The neutron beam irradiation device according to claim 4, characterized in that the control unit comprises a treatment information storage unit that stores past treatment information from the neutron beam irradiation device, and an irradiation setting unit that sets the irradiation mode based on the past treatment information and lesion examination information of the patient who is scheduled to receive treatment this time.

6. The neutron beam irradiation apparatus according to claim 5, characterized in that the irradiation setting unit sets the irradiation mode using a machine learning model.

7. The neutron beam therapy information according to claim 5, wherein the past treatment information includes patient basic information such as age and sex for each patient who has received treatment to date, lesion examination information, and irradiation method information indicating the method of neutron beam irradiation to the lesion.

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