JP2020130643A - Neutron capture therapy system - Google Patents

Abstract

To provide a neutron capture therapy system capable of improving reliability of detection of a person other than an irradiated body in an irradiation chamber.SOLUTION: A neutron capture therapy system for irradiating an irradiated body with a neutron beam, includes: an irradiation chamber that is surrounded by an interception wall for intercepting radiation of the neutron beam from the inside to the outside of the chamber and that is for placing the irradiated body in the chamber and irradiating the irradiated body with the neutron beam; a neutron-beam irradiation portion that irradiates the inside of the irradiation chamber with the neutron beam; a detection portion that detects an object person other than the irradiated body in the irradiation chamber; and a control portion that does not allow the neutron-beam irradiation portion to perform irradiation with the neutron beam unless a state becomes a state in which no object person in the irradiation chamber is detected by the detection portion.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a neutron capture therapy system.

Patent Document 1 describes a neutron capture therapy system used for neutron capture therapy (NCT: NEUTRON CAPTURE THEPARTY). In NCT treatment using this system, the drug is first administered to the patient. The agents comprise substances that react with neutrons, such as ^{10 B,} has a property of being taken up selectively in cancer cells to be treated. Then, when the patient to which the drug is administered is irradiated with neutron rays, the reactants taken into the cancer cells of the patient react with the neutron rays to generate heavily charged particles. Only cancer cells are selectively destroyed by the scattering of these heavily charged particles.

JP-A-2017-042310

By the way, it is required to improve the certainty that the irradiation of neutron rays is performed in a state where a person other than the irradiated body (patient) (for example, a worker such as a doctor or a radiologist) is discharged from the irradiation room. However, since the detection of whether or not a person other than the irradiated body is present in the irradiation room is performed visually by the operator, there is room for improvement in certainty.

In view of the above circumstances, an object of the present invention is to provide a neutron capture therapy system capable of improving the certainty of detection of a person other than the irradiated body in the irradiation chamber.

One embodiment of the present invention is a neutron capture therapy system that irradiates an irradiated body with neutron rays. This neutron capture therapy system is surrounded by a shielding wall that blocks the radiation of neutrons from the room to the outside, and the irradiated body is placed indoors to irradiate the neutrons in the irradiation room and inside the irradiation room. A neutron irradiation unit that irradiates a neutron beam, a detection unit that detects a target person other than the irradiated object in the irradiation room, and a neutron beam unless the detection unit detects the target person in the irradiation room. It is provided with a control unit that does not irradiate the irradiation unit with neutron rays.

In this neutron capture therapy system, the irradiated body is placed in the irradiation chamber. When a subject who is a person other than the irradiated body is in the irradiation room, it is detected by the detection unit. The control unit does not irradiate the neutron beam irradiation unit with neutron rays unless the detection unit detects the target person in the irradiation room. When the detection unit does not detect the target person in the irradiation room, the neutron beam irradiation unit starts irradiating the irradiated body with the neutron beam. Therefore, based on the detection result of the detection unit, it is possible to start the neutron irradiation by the neutron beam irradiation unit after leaving the subject in the irradiation room. Therefore, it is possible to improve the certainty of detection of a person other than the irradiated body in the irradiation chamber.

In addition, the detection unit is a reception unit that accepts an input to enter the irradiation room and an input to leave the irradiation room by the target person, and whether or not the target person in the irradiation room is not detected based on the input of the reception unit. It has a determination unit for determining whether or not. According to such a detection unit, whether or not the target person in the irradiation room is not detected by the determination unit is determined by inputting that the target person enters or leaves the room at the reception unit. Therefore, the detection unit can easily detect the target person in the irradiation room.

Further, a shielding door for closing the entrance / exit provided on the shielding wall is further provided, and the control unit controls the opening / closing of the shielding door based on the input of the reception unit. In this case, the subject in the irradiation room is managed based on the input in the reception unit and the opening / closing of the shielding door in the control unit. Therefore, the determination unit can determine with high accuracy whether or not the target person in the irradiation chamber is not detected.

In addition, the detection unit is a detector having a light emitting device that emits light and a light receiving device that receives light from the light emitting device, and whether or not the target person in the irradiation room is not detected based on the detection result of the detector. It has a determination unit for determining. Such a detector can automatically detect the entry / exit operation of the subject by using light. Therefore, the determination unit can easily determine whether or not the target person in the irradiation chamber is not detected without limiting the movement of the target person.

Further, the detection unit includes a plurality of detectors and an estimation unit that estimates the presence of the target person in the irradiation chamber based on the detection results of the plurality of detectors. According to such an estimation unit, the object in the irradiation room is estimated by estimating whether the subject is moving in the entry direction or the exit direction based on the difference in detection timings of a plurality of detectors. The existence of a person can be estimated. In addition, since the irradiated body is placed on a treatment table larger than the subject and enters the room, a plurality of detectors react at the same time. Therefore, the estimation unit can estimate the existence of the target person in the irradiation room after distinguishing the target person who enters or leaves the irradiation room from the irradiated body or object other than the target person. Therefore, the determination unit can determine with high accuracy whether or not the target person in the irradiation chamber is not detected.

Further, the detection unit includes a heat sensing unit that detects the movement of the heat source in the irradiation chamber and a determination unit that determines whether or not the target person in the irradiation chamber is not detected based on the detection result in the heat sensing unit. Have. According to such a heat sensing unit, the subject in the irradiation chamber can be directly sensed. Therefore, the determination unit can easily determine whether or not the target person in the irradiation chamber is detected.

Further, the heat sensing unit senses the movement of the heat source in the irradiation chamber except at least the place where the irradiated body is arranged. According to such a heat sensing unit, even when the irradiated body arranged in the irradiation chamber moves, it is possible to prevent the irradiated body from being erroneously detected as a target person in the irradiation chamber. Therefore, the determination unit can determine with high accuracy whether or not the target person in the irradiation chamber is not detected.

According to the neutron capture therapy system of the present invention, it is possible to improve the certainty of detection of a person other than the irradiated body in the irradiation chamber.

FIG. 1 is a plan view schematically showing a neutron capture therapy system according to the first embodiment. FIG. 2 is a flowchart showing a detection process of a target person in the irradiation chamber according to the first embodiment. FIG. 3 is a flowchart showing the detection process of the target person in the irradiation chamber according to the first embodiment. FIG. 4 is a plan view schematically showing the neutron capture therapy system according to the second embodiment. FIG. 5 is a flowchart showing the detection process of the target person in the irradiation chamber according to the second embodiment. FIG. 6 is a side view schematically showing the neutron capture therapy system according to the third embodiment. FIG. 7 is a plan view schematically showing the sensing range of the heat sensing unit according to the third embodiment. FIG. 8 is a flowchart showing the detection process of the target person in the irradiation chamber according to the third embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and duplicate description will be omitted. An XYZ coordinate system is set in each figure, and X, Y, and Z are used to explain the positional relationship of each component. Here, the X-axis is the emission direction of the neutron beam N emitted from the neutron beam generation unit 8, and the Z-axis is the direction perpendicular to the floor surface. The Y-axis is a direction orthogonal to the emission direction of the neutron beam N (X-axis direction) and the direction perpendicular to the floor surface (Z-axis direction).

<First Embodiment>
The neutron capture therapy system is a device for performing cancer treatment using boron neutron capture therapy (BNCT: Boron Neutron Capture Therapy). In neutron capture therapy, cancer treatment is performed by irradiating a patient (an example of an irradiated body) to which boron ( ¹⁰ B) has been administered with neutron rays.

FIG. 1 is a plan view schematically showing a neutron capture therapy system according to the first embodiment. As shown in FIG. 1, the neutron capture therapy system 1 emits a neutron beam N to a neutron beam irradiation unit 2 for generating and irradiating a therapeutic neutron beam N and a patient S (an example of an irradiated body). The irradiation chamber 3 for irradiation, the control device 10 for controlling the irradiation of the neutron beam N in the neutron beam irradiation unit 2, and the detection unit for detecting the subject C who is a person other than the patient S in the irradiation chamber 3. 20 and. The target person C is, for example, a worker who arranges the patient S in the irradiation room 3, a worker who performs maintenance in the irradiation room 3, a visitor around the irradiation room 3, or a person accompanying them. The neutron capture therapy system 1 may include a preparation room 4 for preparing for irradiation and a control room 6 for managing the work process.

The neutron beam irradiation unit 2 is configured to generate a neutron beam N in the irradiation chamber 3 so that the patient S can be irradiated with the neutron beam N. The neutron beam irradiation unit 2 includes an accelerator 7 such as a cyclotron, a neutron beam generation unit 8 that generates a neutron beam N from a charged particle beam P, a beam transport path 12 that transports the charged particle beam P to the neutron beam generation unit 8. It has. The accelerator 7 and the beam transport path 12 are arranged in the charged particle beam generation chamber 11. The charged particle beam generation chamber 11 is a closed space covered with a concrete shielding wall W.

The accelerator 7 accelerates a charged particle which is a proton to produce a charged particle beam P which is a proton beam and emits it. The accelerator 7 has an ability to generate a charged particle beam P having a beam radius of 40 mm and a beam radius of 60 kW (= 30 MeV × 2 mA), for example.

The beam transport path 12 emits the charged particle beam P to the neutron beam generation unit 8. One end of the beam transport path 12 is connected to the accelerator 7, and the other end is connected to the neutron beam generator 8. The beam transport path 12 may be provided with a beam control device such as a beam adjusting unit, a current monitor, and a charged particle beam scanning unit, if necessary. The beam adjusting unit controls the traveling direction and the beam diameter of the charged particle beam P. The current monitor measures the current value (that is, charge, irradiation dose rate) of the charged particle beam P in real time. The charged particle beam scanning unit scans the charged particle beam P and controls the irradiation position of the charged particle beam P with respect to the target T.

The neutron beam generation unit 8 includes a target T for generating a neutron beam N, a moderator 8a for decelerating the neutron beam N, and a shield 8b. The moderator 8a and the shield 8b form a moderator.

Here, the neutron beam N generated by the neutron beam generation unit 8 includes a fast neutron beam, an extrathermal neutron beam, a thermal neutron beam, and a gamma ray. Of these, the thermal neutron beam mainly exerts an effective therapeutic effect by nuclear reaction with boron taken into the tumor in the body of patient S. A part of the extrathermal neutron beam contained in the beam of the neutron beam N is also decelerated in the body of the patient S to become a thermal neutron beam that exerts the above therapeutic effect. A thermal neutron beam is a neutron beam having an energy of 0.5 eV or less.

The target T is irradiated with a charged particle beam P to generate a neutron beam N. The target T is formed of, for example, beryllium (Be) and has a disk shape having a diameter of 160 mm.

The moderator 8a decelerates the neutron beam N emitted from the target T. The neutron beam N decelerated by the moderator 8a and reduced to a predetermined energy is also called a therapeutic neutron beam. The moderator 8a has, for example, a laminated structure made of a plurality of different materials. The material of the moderator 8a is appropriately selected depending on various conditions such as the energy of the charged particle beam P.

For example, when the output from the accelerator 7 is a proton beam of 30 MeV and a beryllium target is used as the target T, the moderator 8a can be made of lead, iron, aluminum, or calcium fluoride. Further, when the output from the accelerator 7 is a proton beam of 11 MeV and a beryllium target is used as the target T, the material of the moderator 8a can be heavy water (D2O) or lead fluoride. Further, when the output from the accelerator 7 is a proton beam of 2.8 MeV and a lithium target is used as the target T, the material of the moderator 8a is fluental (trade name: aluminum, aluminum fluoride, lithium fluoride). Can be a mixture of). Further, when the output from the accelerator 7 is a proton beam of 50 MeV and a tungsten target is used as the target T, the material of the moderator 8a can be iron or fluental.

The shield 8b shields the neutron beam N and radiation such as gamma rays generated by the generation of the neutron beam N from being emitted to the outside, and shields the charged particle beam generation chamber 11 and the irradiation chamber 3 from each other. At least a part of it is embedded in the wall W1.

In the neutron capture therapy system 1, the irradiation room 3 and the preparation room 4 are connected to each other via a communication room 14.

The irradiation room 3 is a room in which the patient S is arranged in the room in order to irradiate the patient S with the neutron beam N. The irradiation chamber 3 is arranged on an extension line in the direction in which the beam transport path 12 extends. As an example, the size of the irradiation chamber 3 is 3.5 m in width × 5 m in depth × 3 m in height. The irradiation chamber 3 is composed of a shielding space 3a surrounded by a shielding wall W2, a doorway 3b through which the patient S enters and exits, and a shielding door D1 that opens and closes the doorway 3b.

The shielding wall W2 forms a shielding space 3a. In this shielded space 3a, it is suppressed that radiation enters the room from the outside of the irradiation room 3 and that radiation is emitted from the room to the outside. That is, the shielding wall W2 blocks the radiation of the neutron beam N from the inside of the irradiation chamber 3 to the outside. The shielding wall W2 is integrally formed with the shielding wall W that defines the charged particle beam generation chamber 11. The shielding wall W2 is a concrete wall having a thickness of 2 m or more. A shielding wall W1 that separates the charged particle beam generation chamber 11 and the irradiation chamber 3 is provided between the charged particle beam generation chamber 11 and the irradiation chamber 3. The shielding wall W1 forms a part of the shielding wall W.

A doorway 3b is provided in a part of the shielding wall W2. A shielding door D1 is arranged at the entrance / exit 3b. The shielding door D1 is for suppressing radiation in the shielding space 3a from being radiated to the communication chamber 14. The shielding door D1 is made of a radiation shielding member such as lead. The shielding door D1 moves on a rail provided in the irradiation chamber 3 by being given a driving force by a motor or the like. Since the shielding door D1 is a heavy object, a high torque motor, a speed reducer, or the like is used as a mechanism for driving the shielding door D1.

The preparation room 4 is a room for carrying out the preparatory work necessary for irradiating the patient S with the neutron beam N. The preparatory work includes, for example, restraining the patient S on the treatment table 15 and aligning the collimator with the patient S. The treatment table 15 is, for example, a mobile bed or a wheelchair. The preparation chamber 4 is arranged so as to be separated from the irradiation chamber 3 along the Y-axis direction. A shielding wall W3 that separates the preparation chamber 4 and the irradiation chamber 3 is provided between the preparation chamber 4 and the irradiation chamber 3. The thickness of the shielding wall W3 is, for example, 3.2 m. That is, the preparation chamber 4 and the irradiation chamber 3 are separated by 3.2 m along the Y-axis direction.

The preparation room 4 may be used as a room for other purposes. The preparation room 4 may be a shielded space surrounded by a shielding wall W like the irradiation room 3, or may be a non-shielding space not surrounded by the shielding wall W.

The shielding wall W3 is provided with a communication room 14 that communicates from the preparation room 4 to the irradiation room 3. The communication room 14 is a room for moving the treatment table 15 in which the patient S is restrained between the preparation room 4 and the irradiation room 3. As an example, the size of the communication room 14 is 1.5 m in width × 3.2 m in depth × 2.0 m in height. A door D2 is arranged between the preparation room 4 and the communication room 14.

The control room 6 is a room for controlling the entire process performed by using the neutron capture therapy system 1. A manager enters the control room 6 and manages the entire process by using a control device 10 for operating the neutron irradiation unit 2 arranged in the control room 6.

The control device 10 is composed of, for example, a control device such as a computer. The hardware of the control device 10 includes, for example, a CPU (Central Processing Unit), a ROM (Read OnlyMemory), a RAM (Random Access Memory), an A / D conversion circuit, a D / A conversion circuit, and a communication I / F (interface). It consists of a circuit (control) board on which the circuit is mounted. The CPU, ROM, RAM, A / D conversion circuit, D / A conversion circuit, and communication I / F circuit are connected to the bus. The A / D conversion circuit and the D / A conversion circuit are connected to the bus via the input / output I / F circuit.

The control device 10 includes an irradiation control unit 16 (an example of a control unit), an operation control unit 17, a recording unit 18, and a determination unit 40. The recording unit 18 and the determination unit 40 are included in the detection unit 20. The detection unit 20 detects the target person C in the irradiation chamber 3.

The irradiation control unit 16 controls the start and stop of the irradiation of the neutron beam N based on the command from the administrator. For example, the administrator commands the start and stop of the irradiation of the neutron beam N by operating the screen displayed on the touch panel connected to the control device 10. Further, the irradiation control unit 16 controls the start and stop of the irradiation of the neutron beam N based on the detection result of the detection unit 20. The control of the start of irradiation of the neutron beam N is, for example, the control of the start of emission of the charged particle beam P from the accelerator 7. For example, when the irradiation control unit 16 transmits an irradiation start signal, which is a signal to the effect that the irradiation of the neutron beam N is started, to the neutron beam irradiation unit 2, the neutron beam irradiation unit 2 transmits the neutron beam N into the irradiation chamber 3. Irradiate. For example, when the irradiation control unit 16 transmits an irradiation stop signal, which is a signal to stop the irradiation of the neutron beam N, to the neutron beam irradiation unit 2, the neutron beam irradiation unit 2 causes the neutron beam N into the irradiation chamber 3. Irradiation is stopped.

Here, in the neutron capture therapy, the treatment of irradiating one patient S with the neutron beam N only once is currently adopted. Therefore, in the neutron capture therapy, it is not preferable to interrupt the irradiation of the neutron beam N to the patient S once started to be irradiated. On the other hand, in the unlikely event that the subject C is irradiated with the neutron beam N while remaining in the irradiation chamber 3, the irradiation of the neutron beam N has to be interrupted. Therefore, by improving the certainty of detection of the subject C in the irradiation chamber 3, it is possible to suppress the occurrence of the event that the subject C remains in the irradiation chamber 3 when the neutron beam N is irradiated, and the patient S. It is possible to suppress the interruption of the irradiation of the neutron beam N.

Specifically, the irradiation control unit 16 does not irradiate the neutron beam N into the irradiation chamber 3 by the neutron beam irradiation unit 2 unless the target person C in the irradiation chamber 3 is detected by the detection unit 20. The irradiation control unit 16 is in a state in which the neutron beam irradiation unit 2 is not irradiated with the neutron beam N unless the above conditions are satisfied, regardless of any other conditions. Even if the above conditions are satisfied, the irradiation control unit 16 may be in a state in which the neutron beam irradiation unit 2 allows irradiation of the neutron beam N after satisfying other conditions.

A method in which the irradiation control unit 16 does not irradiate the irradiation chamber 3 with the neutron beam N by the neutron beam irradiation unit 2 will be described. The irradiation control unit 16 may impose control restrictions so as not to generate the neutron beam N in the neutron beam irradiation unit 2. For example, the irradiation control unit 16 does not have to accept a command from the administrator. In this case, the irradiation control unit 16 does not display the option of starting the irradiation of the neutron beam N on the screen displayed on the touch panel that can be operated by the administrator unless the above conditions are satisfied. Further, the irradiation control unit 16 does not have to generate the irradiation start signal transmitted to the neutron beam irradiation unit 2 even if the command from the administrator is received. Even in the state where the irradiation start signal is generated, the irradiation control unit 16 is controlledly blocked before being transmitted to the neutron beam irradiation unit 2.

When the neutron irradiation unit 2 receives the irradiation start signal, the irradiation control unit 16 may control the mechanism of the neutron irradiation unit 2 so as not to generate the neutron beam N in the irradiation chamber 3. .. For example, the irradiation control unit 16 does not irradiate the irradiation chamber 3 with the neutron beam N at least in either the generation or irradiation of the charged particle beam P in the accelerator 7 or the transportation of the charged particle beam P in the beam transport path 12. It may be regulated as follows. The irradiation control unit 16 may shield the irradiation chamber 3 from being irradiated with the neutron beam N by the shield 8b of the neutron beam generation unit 8. The irradiation control unit 16 may regulate the generation of the neutron beam N in the irradiation chamber 3 by using another neutron beam N shielding mechanism provided in the neutron beam irradiation unit 2.

Further, the irradiation control unit 16 switches from "a state in which the neutron beam irradiation unit 2 is not irradiated with the neutron beam N" to "a state in which the neutron beam irradiation unit 2 allows irradiation of the neutron beam N". This switching is performed when the target person C in the irradiation chamber 3 is not detected by the detection unit 20. For example, the irradiation control unit 16 switches ON / OFF of the irradiation prohibition flag. If the subject C in the irradiation chamber 3 is not detected by the detection unit 20, the irradiation prohibition flag is turned ON. When the irradiation prohibition flag is ON, the irradiation is regulated under the control as described above, or the irradiation is mechanically regulated. When the target person C in the irradiation chamber 3 is not detected by the detection unit 20, the irradiation prohibition flag is turned off. When the irradiation prohibition flag is OFF, the irradiation control unit 16 transmits an irradiation start signal to the neutron beam irradiation unit 2 according to the command of the administrator, so that the neutron beam irradiation unit 2 causes the neutron beam into the irradiation chamber 3. Irradiate N.

The operation control unit 17 controls the opening and closing of the shielding door D1. The operation control unit 17 opens or closes the shielding door D1 based on, for example, the detection result of the detection unit 20.

The recording unit 18 records the occupancy information of the subject C in the irradiation room 3 detected by the detection unit 20. The occupancy information includes at least one of the information that can identify the individual of the subject C or the number of the subjects C in the irradiation room 3. The occupancy information of the recording unit 18 is updated at predetermined time intervals.

The detection unit 20 has a reception unit 30. The reception unit 30 is provided in the irradiation room 3, the preparation room 4, the communication room 14, and the like. The reception unit 30 receives an input from the subject C to enter the irradiation room 3 and an input to leave the irradiation room 3. The control device 10 records the occupancy information in the recording unit 18 based on the input received by the reception unit 30. The reception unit 30 may directly record the occupancy information in the recording unit 18.

The reception unit 30 has, for example, a door front reception unit 31. The door front reception unit 31 receives an input from the subject C to enter the irradiation room 3 and an input to leave the irradiation room 3. The door front reception unit 31 is provided in, for example, the contact room 14. The format of the door front reception unit 31 is, for example, a card reader, a touch panel, or a button.

When the door front reception unit 31 is a card reader, the target person C inputs or leaves the irradiation room 3 by holding an ID card corresponding to the target person C one-to-one over the door front reception unit 31. You can enter that. For example, when the ID card is held over the door front reception unit 31 an odd number of times, the input is to enter the irradiation room 3, and when the ID card is held over the door front reception unit 31 an even number of times, the room is exited from the irradiation room 3. It is an input to the effect.

When the door front reception unit 31 is a touch panel, for example, the door front reception unit 31 displays on the screen the option of entering the irradiation room 3 or leaving the irradiation room 3. The subject C inputs that he / she enters the irradiation room 3 or that he / she leaves the irradiation room 3 by selecting the option shown in the reception unit 31 in front of the door.

When the door front reception unit 31 is a button, for example, the target person C selects and presses a button for entering the irradiation room 3 provided in the door front reception unit 31 or a button for leaving the irradiation room 3. As a result, it is possible to input to enter the irradiation room 3 or to leave the irradiation room 3. In the form of the door front reception unit 31, for example, two or more of a card reader, a touch panel, a button, and the like may be used together.

The determination unit 40 determines, for example, whether or not the target person C in the irradiation chamber 3 is not detected based on the occupancy information in the recording unit 18. The determination unit 40 determines, for example, whether or not the target person C in the irradiation room 3 is not detected based on the occupancy information in the recording unit 18 updated by the reception unit 30.

Specifically, if at least one subject C inputs that he / she will enter the room at the reception unit 30 and does not input that he / she leaves the room at the reception unit 30, the occupancy information will be stored in the irradiation room 3. Indicates that at least one subject C remains. In this case, the determination unit 40 determines that the target person C is not detected in the irradiation chamber 3 (that is, even one target person C is detected). In this case, the irradiation control unit 16 turns on the irradiation prohibition flag based on the result of the determination of the determination unit 40, and the neutron beam irradiation unit 2 does not irradiate the neutron beam N.

Further, when all the target persons C input that they enter the room at the reception unit 30 and input that they leave the room at the reception unit 30, all the target persons C leave the room and irradiate the room information. It is shown that no subject C remains in the room 3. In this case, the determination unit 40 determines that the subject C is not detected in the irradiation chamber 3. Based on the result of the determination by the determination unit 40, the irradiation control unit 16 turns off the irradiation prohibition flag and causes the neutron beam irradiation unit 2 to irradiate the neutron beam N. The determination unit 40 may make a determination by referring only to the number of people in the room from the room information, and by acquiring only the input status of the reception unit 30 and calculating the number of people in the room from the input status. A determination may be made.

When the occupancy information indicates that at least one target person C exists in the irradiation room 3, the operation control unit 17 sets the shielding door D1 to the open state. Since the neutron beam N is not irradiated while the subject C is present in the irradiation chamber 3, the irradiation control unit 16 irradiates the neutron beam N with the shielding door D1 open. Absent. Further, when the occupancy information indicates that all the target persons C do not exist in the irradiation room 3, the operation control unit 17 sets the shielding door D1 in a closed state. Since the neutron beam N can be irradiated when the subject C is not present in the irradiation chamber 3, the irradiation control unit 16 irradiates the neutron beam N while the shielding door D1 is closed.

The operation control unit 17 does not have to open and close the shielding door D1 unless there is an input to the reception unit 30. At this time, if there is no input in the reception unit 30 to enter the irradiation room 3, the shielding door D1 is in a closed state. As a result, it is possible to prevent the subject C from entering the irradiation room 3 without going through the reception unit 30. In addition, when a plurality of types of the door front reception unit 31 are used together, the door front reception unit 31 or the door front reception unit 31 or unless the input to enter the irradiation room 3 or the input to leave the irradiation room 3 in each type match. The determination unit 40 does not have to accept the input by the subject C.

Next, in the reception unit 30 and the determination unit 40, the first reception process, which is the process in which the subject C enters the irradiation room 3 and then leaves the room 3, will be described. FIG. 2 is a flowchart showing a detection process of a target person in the irradiation chamber according to the first embodiment. As shown in FIG. 2, in the first reception process S100, first, as an entry input process (S2), the door front reception unit 31 provided in the communication room 14 enters the irradiation room 3 by at least one subject C. Accepts input to the effect. If at least one subject C does not input to the reception unit 31 in front of the door, the shielding door D1 is in a closed state, so that the subject C cannot enter the irradiation room 3.

Subsequently, as the room entry recording process (S4), the control device 10 records the room occupancy information in the recording unit 18 based on the input of the target person C in the door front reception unit 31. At this time, the occupancy information indicates that at least one subject C who has input to enter the room at the reception unit 31 in front of the door remains in the irradiation room 3.

Subsequently, as the door opening process (S6), the operation control unit 17 opens the shielding door D1 based on the input from the subject C in the door front reception unit 31 that the subject C enters the irradiation room 3. After entering the irradiation room 3, the subject C performs an action in the irradiation room 3. Subsequently, as the exit input process (S22), the door front reception unit 31 receives an input by the subject C to leave the irradiation room 3.

Subsequently, as the exit recording process (S24), the control device 10 records the occupancy information in the recording unit 18 based on the input of the target person C in the door front reception unit 31. At this time, the occupancy information indicates that the subject C who has entered the fact that he / she will leave the reception unit 31 in front of the door does not remain in the irradiation room 3.

Subsequently, as the occupancy determination process (S26), the determination unit 40 determines whether or not the target person C in the irradiation room 3 is not detected based on the occupancy information of the recording unit 18. When the recording unit 18 has only the occupancy information indicating that all the target persons C in the irradiation room 3 are not present, the determination unit 40 determines that the target person C in the irradiation room 3 is not detected.

In the occupancy determination process (S26), when the recording unit 18 has occupancy information indicating that there is at least one target person C in the irradiation room 3, the determination unit 40 detects the target person C in the irradiation room 3. It is determined that the state is not not (that is, the state in which even one subject C is detected). In the occupancy information indicating that the recording unit 18 has the target person C in the irradiation room 3, for example, when there are a plurality of target persons C, the reception unit 31 in front of the door inputs that the room is to be entered in the irradiation room 3. This includes cases where even one of the multiple target persons has not entered the fact that they will leave the room. In this case, the irradiation prohibition flag in the irradiation control unit 16 remains ON. The control device 10 performs the occupancy determination process (S26) again after a predetermined time. In this case, the control device 10 may notify the target person C or the administrator to confirm. After that, the exit input process (S22) and the exit record process (S24) are executed by the other subject C, and whether all the subject Cs have left the irradiation room 3 again in the occupancy determination process (S26). Is determined.

When the determination unit 40 determines in the room presence determination process (S26) that the target person C in the irradiation chamber 3 is not detected, the operation control unit 17 subsequently performs the door closing process (S28). The shielding door D1 is closed based on the occupancy information of the recording unit 18.

Subsequently, as an irradiation process (S30), the control device 10 irradiates the neutron beam N via the neutron beam irradiation unit 2. When the determination unit 40 determines that the subject C in the irradiation chamber 3 is not detected, the irradiation prohibition flag in the irradiation control unit 16 is turned off. For example, the control device 10 displays an option for starting the irradiation of the neutron beam N on the screen of the touch panel connected to the control device 10 to enable input. As a result, the administrator can start the irradiation of the neutron beam N by the neutron beam irradiation unit 2 after confirming with the detection unit 20 as well as his own visual inspection.

See FIG. 1 again. The reception unit 30 may further have a reception unit 32 after the door. The reception unit 32 after the door is provided in the irradiation room 3. The door rear reception unit 32 is, for example, a card reader, a touch panel, buttons, or a combination thereof. The rear door reception unit 32 may have the same format as the front door reception unit 31. The recording unit 18 records the occupancy information of the subject C in the irradiation room 3 based on the input received by the reception unit 32 after the door. In the recording unit 18, when the target person C inputs to the door front reception unit 31 and the door rear reception unit 32 and the recorded occupancy information does not match, the control device 10 confirms with the target person C or the manager. You may give a warning to do so. In the occupancy information of the recording unit 18, all the target persons C who have entered the fact that they will enter the door front reception unit 31 and the door rear reception unit 32 will leave the door front reception unit 31 and the door rear reception unit 32. Unless the input record is recorded, the determination unit 40 determines that the target person C in the irradiation chamber 3 is not in a state where it is not detected (that is, a state in which even one target person C is detected).

If the target person C who has entered that he / she will enter only the door front reception unit 31 has entered that he / she will leave the room only in the door front reception unit 31, the occupancy information will be input that the target person C will leave the room. It will be a recorded record. When the subject C who entered that he / she entered only the reception section 32 after the door entered that he / she would leave the room only in the reception section 32 after the door, the occupancy information was entered that he / she would leave the room by the subject C. It will be a record. When the subject C who has input that he / she will enter only the reception unit 32 after the door is recorded in the room occupancy information of the recording unit 18, the control device 10 notifies, for example, an abnormality. The control device 10 may notify and prompt the target person C to input information to enter the room at the reception unit 31 in front of the door.

The operation control unit 17 closes the shielding door D1 by inputting that the subject C who has entered the irradiation room 3 has entered the room at the reception unit 32 after the door. The operation control unit 17 opens the shielding door D1 when the subject C who leaves the irradiation room 3 inputs that the reception unit 32 is leaving the room after the door.

The second reception process, which is a process in which the subject C enters the irradiation room 3 and then leaves the room, when the reception unit 30 further has a reception unit 32 after the door will be described. FIG. 3 is a flowchart showing the detection process of the target person in the irradiation chamber according to the first embodiment. As shown in FIG. 3, the second reception process S200 includes the same processing as that included in the first reception process S100. First, the control device 10 in the second reception process S200 executes the same processes as the room entry input process (S2), the room entry record process (S4), and the door opening process (S6) in the first reception process S100.

In the second reception process S200, between the door opening process (S6) and the exit input process (S22) in the first reception process S100, the entry completion input process (S10), the entry completion record process (S12), and the door at the time of entry are entered. It has a closing process (S14), an exit start input process (S16), an exit start recording process (S18), and a door opening process when leaving the room (S20) in this order.

As the entry completion input process (S10), the door rear reception unit 32 installed in the irradiation room 3 receives an input by the subject C to the effect that he / she has entered the irradiation room 3. Subsequently, as the entry completion recording process (S12), the control device 10 records the occupancy information in the recording unit 18 based on the input of the target person C in the reception unit 32 after the door. Subsequently, as a door closing process (S14) when entering the room, the operation control unit 17 closes the shielding door D1 based on the occupancy information of the recording unit 18. As a result, the subject C who does not input at the reception unit 31 in front of the door is prevented from entering the irradiation room 3. After entering the irradiation room 3, the subject C performs an action in the irradiation room 3.

As the exit start input process (S16), the door rear reception unit 32 installed in the irradiation room 3 receives an input from the subject C to leave the room from the irradiation room 3. Subsequently, as the exit start recording process (S18), the control device 10 records the occupancy information in the recording unit 18 based on the input of the target person C in the reception unit 32 after the door. Subsequently, as a door opening process (S20) when leaving the room, the operation control unit 17 opens the shielding door D1 based on the occupancy information of the recording unit 18. Even if the shielding door D1 is blocked when another target person C inputs to leave the irradiation room 3 at the reception unit 31 in front of the door, the target person C in the irradiation room 3 receives after the door. In the unit 32, it is possible to input that the room is to be left. As a result, the subject C is suppressed from remaining in the irradiation chamber 3.

Subsequently, the control device 10 in the second reception process S200 executes the same processing as the exit input process (S22) and the exit recording process (S24) in the first reception process S100. Subsequently, as the occupancy determination process (S26), the determination unit 40 determines whether or not the target person C in the irradiation room 3 is not detected based on the occupancy information of the recording unit 18. When the recording unit 18 has occupancy information indicating that all the target persons C in the irradiation room 3 are not present, the determination unit 40 determines that the target person C in the irradiation room 3 is not detected. In the occupancy information of the recording unit 18, all the target persons C who have input that they will enter the reception unit 31 in front of the door and the reception unit 32 after the door have entered that they will leave the reception unit 31 in front of the door and the reception unit 32 after the door. If the record is recorded, the determination unit 40 determines that the subject C in the irradiation chamber 3 is not detected.

In the occupancy determination process (S26), when the recording unit 18 has occupancy information indicating that the target person C in the irradiation room 3 is present, the determination unit 40 is in a state where the target person C in the irradiation room 3 is not detected. It is determined that there is no subject C (that is, even one subject C is detected). If the occupancy information of the recording unit 18 does not indicate that the subject C will leave the room in at least one of the front door reception unit 31 and the rear door reception unit 32, the determination unit 40 irradiates. It is determined that the subject C in the room 3 is not in a state where it is not detected. In this case, the control device 10 performs the occupancy determination process (S26) again after a predetermined time. In this case, the control device 10 may notify the warning to the target person C or the administrator to confirm. After that, at least one set of the exit start input process (S16) and the exit start record process (S18), or the exit input process (S22) and the exit record process (S24) is executed by the other subject C to determine the presence of the room. In the process (S26), it is determined again whether all the subjects C have left the irradiation chamber 3. With respect to the processing already performed by the other target person C, the processing is appropriately omitted by the control device 10.

When the determination unit 40 determines in the room presence determination process (S26) that the target person C in the irradiation room 3 is not detected, then in the second reception process S200, the control device 10 receives the first reception. The same process as the door closing process (S28) and the irradiation process (S30) in the process S100 is executed.

As described above, according to the neutron capture therapy system 1 of the present embodiment, it is possible to improve the certainty of detection of the subject C who is a person other than the patient S (irradiated body) in the irradiation chamber 3. It is possible to suppress the occurrence of the event that the subject C remains in the irradiation chamber 3 during the irradiation of the neutron beam N, and to suppress the interruption of the irradiation of the neutron beam N to the patient S. Further, when the reception unit 30 inputs that the target person C enters or leaves the room, the determination unit 40 determines whether or not the target person C in the irradiation room 3 is detected. Therefore, the detection unit 20 can easily detect the target person C in the irradiation chamber 3. Further, the subject C in the irradiation chamber 3 is managed based on the input in the reception unit 30 and the opening / closing of the shielding door D1 in the operation control unit 17. Therefore, the determination unit 40 can determine with high accuracy whether or not the subject C in the irradiation chamber 3 is detected.

<Second Embodiment>
Next, the neutron capture therapy system 1 according to the second embodiment will be described. In the description of the present embodiment, the differences from the first embodiment will be described, and duplicate description will be omitted. In the neutron capture therapy system 1A according to the second embodiment, as compared with the neutron capture therapy system 1 according to the first embodiment, the detection unit has a detector and an estimation unit, and the determination unit is the estimation result of the estimation unit. Based on this, it differs in that it is determined whether or not the target person in the irradiation room is not detected.

The detection unit 20 has a detector 50. The detection unit 20 may have an estimation unit 60. FIG. 4 is a plan view schematically showing the neutron capture therapy system according to the second embodiment. As shown in FIG. 4, the detector 50 is provided in the irradiation room 3, the preparation room 4, the communication room 14, and the like, and detects the subject C in the irradiation room 3. That is, the detector 50 is provided at a place where the subject C passes when entering or leaving the irradiation room 3, for example, at a place where the irradiation room 3 and the communication room 14 communicate with each other. The detector 50 is provided, for example, in the vicinity of the shielding door D1.

The detector 50 is, for example, a laser sensor. The detector 50 includes a light emitter 51 that emits light and a light receiver 52 that receives light from the light emitter 51. The light emitted by the light emitter 51 is, for example, a laser. The light emitter 51 and the light receiver 52 are provided apart from each other so that a passing body such as the patient S, the treatment table 15, or the subject C passes between the light emitter 51 and the light receiver 52. It is provided so that the optical path of the light emitted from the light emitter 51 toward the light receiver 52 and the flow line of the subject C intersect. The light emitter 51 and the light receiver 52 are provided at positions where the subject C and other passing bodies can be easily distinguished. The light emitter 51 and the light receiver 52 are provided, for example, at a height at which the long side of the treatment table 15 intersects the optical path of the light emitted from the light emitter 51 toward the light receiver 52.

The light emitted from the light emitter 51 is blocked by a passing body such as the treatment table 15 or the subject C, so that the light is not received by the light receiver 52. At least, the receiver 52 transmits to the estimation unit 60 the light-shielding start time, which is the time when light-shielding starts, and the light-shielding end time, which is the time when light reception starts again. The receiver 52 may directly measure the elapsed light-shielding time, which is the time during which light-shielding is performed, and transmit it to the estimation unit 60.

A plurality of detectors 50 may be provided. That is, the detector 50 has a plurality of light emitters 51 and a plurality of receivers 52. The light emitter 51 and the light receiver 52 have a one-to-one correspondence with each other. The door front detection set 53, which is at least one set of the light emitter 51 and the light receiver 52, is provided, for example, in the vicinity of the shielding door D1 in the communication room 14. The rear-door detection set 54, which is at least one set of the light emitter 51 and the light receiver 52, is provided, for example, in the vicinity of the shielding door D1 in the irradiation chamber 3. The distance between the front door detection set 53 and the rear door detection set 54 is provided so as to be at least shorter than the short side of the treatment table 15.

The estimation unit 60 estimates the presence of the subject C in the irradiation chamber 3 based on the detection results of the plurality of detectors 50. The estimation unit 60 is connected to a plurality of detectors 50. The estimation unit 60 is provided, for example, in the control device 10 of the control room 6. The estimation unit 60 is composed of a control device such as a computer, for example. The hardware of the estimation unit 60 is, for example, a CPU (Central Processing Unit).

The estimation unit 60 calculates the elapsed light-shielding time, which is the time during which light-shielding is performed from the light-shielding start time and the light-shielding end time obtained by the receiver 52. The estimation unit 60 may directly acquire the light-shielding elapsed time from the receiver 52. The estimation unit 60 is based on the detection results obtained from the door front detection set 53 and the door rear detection set 54, between the light emitter 51 and the receiver 52 in the door front detection set 53, and the door rear detection set 54. The moving direction of the passing body passing between the light emitter 51 and the light receiver 52 is estimated. When the light-shielding start time in the front-door detection set 53 is earlier than the light-shielding start time in the rear-door detection set 54, the estimation unit 60 estimates that the passing body has entered the irradiation chamber 3. When the light-shielding start time in the front-door detection set 53 is later than the light-shielding start time in the rear-door detection set 54, the estimation unit 60 estimates that the passing body has left the irradiation chamber 3.

As the estimation of the moving direction of the passing body in the estimation unit 60, the shading end times may be compared and estimated. That is, when the light-shielding end time in the front-door detection set 53 is earlier than the light-shielding end time in the rear-door detection set 54, the estimation unit 60 estimates that the passing body has entered the irradiation chamber 3. When the light-shielding end time in the front-door detection set 53 is later than the light-shielding end time in the rear-door detection set 54, the estimation unit 60 estimates that the passing body has left the irradiation chamber 3.

When the estimation results of the moving direction of the passing body obtained by the light-shielding start time and the light-shielding end time do not match, the estimation unit 60 determines the light-shielding start time or the light-shielding end time of other combinations of the light emitter 51 and the light receiver 52. By using it, the moving direction of the passing body may be estimated. Based on the moving direction, the estimation unit 60 estimates the number of subjects C who have entered the irradiation room 3 and have not left the room.

The estimation unit 60 estimates the presence of a passing body that has passed between the front door detection set 53 and the rear door detection set 54 based on the detection results obtained from the front door detection set and the rear door detection set 54. .. The estimation unit 60 measures the light-shielding start time of the rear-door detection set 54 from the light-shielding start time of the door-front detection set 53 to the light-shielding end time, and the light-shielding elapsed time of the door-front detection set 53 or the door-rear detection set 54. When is longer than the elapsed time of shading of other passing objects, it can be estimated that the treatment table 15 enters the irradiation chamber 3. The estimation unit 60 detects when the light-shielding start time of the door-front detection set 53 is measured from the light-shielding start time of the door-rear detection set 54 to the light-shielding end time, and the light-shielding of the door-front detection set 53 or the door-rear detection set 54 When the elapsed time is longer than the elapsed time of shading of other passing objects, it can be estimated that the treatment table 15 leaves the irradiation room 3.

In cases other than the above, the estimation unit 60 can estimate the passing body as the subject C. For example, when the light-shielding elapsed time in the front-door detection set 53 and the rear-door detection set 54 is shorter than the elapsed light-shielding time in the treatment table 15, the subject C is between the front-door detection set 53 and the rear-door detection set 54. It can be presumed that it is the effect of the foot touching the ground at the same time. The estimation unit 60 records the estimation results such as the estimated movement direction and the number of subjects C in the recording unit 18 as occupancy information.

The detection unit 20 may have an open / close button 33 for operating the opening / closing of the shielding door D1. The open / close button 33 is provided on the wall surface of the communication room 14. The open / close button 33 is provided, for example, at a position farther from the irradiation chamber 3 as compared with the door front detection set 53. The subject C opens or closes via the operation control unit 17 by pressing the open / close button 33, for example. The open / close button 33 is, for example, a touch panel. At this time, an open / close button may be provided in the irradiation chamber 3. The determination unit 40 determines whether or not the subject C in the irradiation chamber 3 is not detected based on the estimation result of the estimation unit 60 in the occupancy information of the recording unit 18.

When the occupancy information indicates that at least one target person C exists in the irradiation room 3, the operation control unit 17 sets the shielding door D1 to the open state. Since the neutron beam N is not irradiated while the subject C is present in the irradiation chamber 3, the irradiation control unit 16 irradiates the neutron beam N with the shielding door D1 open. Absent. Further, when the occupancy information indicates that all the target persons C do not exist in the irradiation room 3, the operation control unit 17 sets the shielding door D1 in a closed state. Since the neutron beam N can be irradiated when the subject C is not present in the irradiation chamber 3, the irradiation control unit 16 irradiates the neutron beam N while the shielding door D1 is closed.

Next, in the detector 50 and the estimation unit 60, the detection process from when the subject C enters the irradiation room 3 to when the subject C leaves the irradiation room 3 will be described. FIG. 5 is a flowchart showing the detection process of the target person in the irradiation chamber according to the second embodiment. In the detection process S300 shown in FIG. 5, first, as an activation process (S40), the control device 10 activates the light emitter 51 and the receiver 52, respectively. The light emitter 51 emits light. The light receiver 52 receives the light from the light emitter 51. The light emitter 51 starts irradiating the laser, for example, toward the light receiver 52.

Subsequently, as the passing body determination process (S42), the determination unit 40 determines whether or not the passing body is detected by the plurality of detectors 50 within a predetermined time. When only one detector 50 detects a passing body, the determination unit 40 does not determine that the passing body has been detected. That is, when one receiver 52 is shielded from light and the other receiver 52 is not shielded from light, for example, in the estimation unit 60, the object is not the passing body but the light emitter 51 and the receiver 52. It is presumed that it occurs when it is provided between and. When it is determined by the determination unit 40 that the passing body is detected, the control device 10 shifts to the next process. When the determination unit 40 determines that the passing body has not been detected, the control device 10 executes the passing body determination process (S42) again after a predetermined time.

Subsequently, as a shielding door determination process (S44), the determination unit 40 determines whether or not the shielding door D1 is in an open state. The subject C, who intends to enter the room, operates the open / close button 33 and then opens the shielding door D1 before entering the irradiation room 3. Since the passing body other than the subject C does not operate the open / close button 33, the shielding door D1 is not opened. When the determination unit 40 determines that the shielding door D1 is in the open state, the control device 10 shifts to the next process. When the determination unit 40 determines that the shielding door D1 is not in the open state, the control device 10 executes the passing body determination process (S42) again after a predetermined time.

Subsequently, as the treatment table determination process (S46), the determination unit 40 determines whether or not the passing objects are simultaneously detected by the plurality of detectors 50 within a predetermined time. When the passing bodies are detected by the plurality of detectors 50 at the same time, in the estimation unit 60, the detected passing bodies are at least as long as the distance between the plurality of detected detectors 50 adjacent to each other. Presumed. The passing body in this case is, for example, patient S or treatment table 15. When it is determined by the determination unit 40 that the passing objects are simultaneously detected, the control device 10 executes the passing object determination process (S42) again after a predetermined time. When it is determined by the determination unit 40 that the passing bodies are not simultaneously detected, the control device 10 shifts to the next process. In this case, in the estimation unit 60, the passing body is estimated to be the subject C.

Subsequently, as the detection determination process (S48), the estimation unit 60 determines whether or not the detector 50 has detected the target person C in the order of the door front detection set 53 and the door rear detection set 54. When the detector 50 detects the target person C in the order of the door front detection set 53 and the door rear detection set 54, the estimation unit 60 estimates that the moving direction of the target person C is the direction of entering the irradiation chamber 3. In this case, subsequently, as a count-up process (S50), the estimation unit 60 calculates the number of target persons C in the irradiation room 3 assuming that the number of target persons C in the irradiation room 3 has increased by one. For example, when the target person C entering the irradiation room 3 is the first person, the estimation unit 60 sets the initial value to "0" and calculates the count as "1".

In the detection determination process (S48), when the detector 50 does not detect the target person C in the order of the door front detection set 53 and the door rear detection set 54, the estimation unit 60 moves the target person C in the irradiation room. It is estimated that the room is going to leave from 3. In this case, subsequently, as a countdown process (S52), the estimation unit 60 calculates the number of subjects C in the irradiation chamber 3 assuming that the number of subjects C in the irradiation chamber 3 has decreased by one. The estimation unit 60 calculates the count as "1" when, for example, there are two subjects C who have entered the irradiation room 3 and the subject C who leaves the irradiation room 3 is the first person.

Following the count-up process (S50) or the countdown process (S52), the estimation unit 60 causes the recording unit 18 to record the estimation result such as the number of people as the recording process (S54). At this time, the control device 10 acquires the open / closed state of the shielding door D1 and causes the recording unit 18 to record the opened / closed state of the shielding door D1.

Subsequently, as a number determination process (S56), the determination unit 40 determines whether or not the number of subjects C in the irradiation chamber 3 is an initial value. The determination unit 40 makes a determination by comparing the occupancy information of the recording unit 18 with the initial value set by the estimation unit 60. When the determination unit 40 determines that the number of subjects C in the irradiation chamber 3 is the initial value, the control device 10 shifts to the next process. When the determination unit 40 determines that the number of subjects C in the irradiation chamber 3 is not the initial value, the irradiation prohibition flag in the irradiation control unit 16 remains ON. The control device 10 executes the passing body determination process (S42) again after a predetermined time.

When the determination unit 40 determines in the number determination process (S56) that the number of subjects C in the irradiation chamber 3 is the initial value, the irradiation prohibition flag in the irradiation control unit 16 is turned off. Subsequently, as an irradiation process (S58), the irradiation control unit 16 irradiates the neutron beam N via the neutron beam irradiation unit 2. The irradiation treatment (S58) is the same treatment as the irradiation treatment (S30) of the first embodiment.

As described above, according to the neutron capture therapy system 1A of the present embodiment, it is possible to improve the certainty of detection of the subject C who is a person other than the patient S (irradiated body) in the irradiation chamber 3. It is possible to suppress the occurrence of the event that the subject C remains in the irradiation chamber 3 when the neutron beam N is irradiated, and to suppress the interruption of the neutron beam N irradiation to the patient S. In addition, the detector 50 can automatically detect the entry / exit operation of the subject C by using light. Therefore, the determination unit 40 can easily determine whether or not the subject C in the irradiation chamber 3 is not detected without limiting the movement of the subject C.

Further, according to the estimation unit 60, the irradiation room is estimated by estimating whether the subject C is moving in the entry direction or the exit direction based on the difference in detection timings of the plurality of detectors 50. The existence of the subject C in 3 can be estimated. Further, since the patient S (irradiated body) is placed on the treatment table 15 which is larger than the subject C and enters the room, a plurality of detectors 50 react at the same time. Therefore, the estimation unit 60 distinguishes between the subject C who enters or leaves the irradiation chamber 3 and the patient S (irradiated body) or object other than the subject C, and then the subject in the irradiation chamber 3. The existence of C can be estimated. Therefore, the determination unit 40 can determine with high accuracy whether or not the subject C in the irradiation chamber 3 is detected.

<Third Embodiment>
Next, the neutron capture therapy system 1B according to the third embodiment will be described. In the description of the present embodiment, the differences from the second embodiment will be described, and duplicate description will be omitted. In the neutron capture therapy system 1B according to the third embodiment, as compared with the neutron capture therapy system 1 according to the first embodiment, the detection unit has a heat sensing unit, and the determination unit has the detection result of the heat sensing unit. Based on this, it differs in that it is determined whether or not the target person in the irradiation room is not detected.

The detection unit 20 has a heat sensing unit. FIG. 6 is a side view schematically showing the neutron capture therapy system according to the third embodiment. As shown in FIG. 6, the heat sensing unit 70 is provided in the irradiation chamber 3 and detects the subject C in the irradiation chamber 3. The heat sensing unit 70 senses the movement of the heat source in the irradiation chamber 3. The heat sensing unit 70 is, for example, an infrared sensor. When the heat sensing unit 70 detects the movement of the heat source, the control device 10 records the subject C as occupancy information in the recording unit 18. When the heat source detected by the heat sensing unit 70 as having a temperature in a range close to the human body temperature (for example, 33 ° C. to 43 ° C.) moves, the control device 10 records it in the recording unit 18 as occupancy information. May be good.

A plurality of heat sensing units 70 may be provided in order to reduce blind spots. The heat sensing unit 70 has, for example, a top surface heat sensing unit 71 and a side surface heat sensing unit 72. The upper surface heat sensing unit 71 is provided on the upper surface of the irradiation chamber 3 and senses the movement of the heat source in the horizontal plane (XY plane) from the upper surface of the irradiation chamber 3 toward the bottom surface of the irradiation chamber 3. The side heat sensing unit 72 is provided on at least one side surface of the irradiation chamber 3 and senses the movement of the heat source in the vertical direction (Z-axis direction) from the side surface of the irradiation chamber 3.

FIG. 7 is a plan view schematically showing the sensing range of the heat sensing unit according to the third embodiment. As shown in FIG. 7, the heat sensing unit 70 senses the movement of the heat source in the range R in the irradiation chamber 3 except at least the place where the patient S is arranged. As a result, even when the patient S arranged in the irradiation chamber 3 moves, it is possible to prevent the patient S from being erroneously detected as the subject C in the irradiation chamber 3.

Next, in the heat sensing unit 70, the heat detection process from when the subject C leaves the irradiation chamber 3 to when the neutron beam N is irradiated will be described. FIG. 8 is a flowchart showing the detection process of the target person in the irradiation chamber according to the third embodiment. As shown in FIG. 8, in the heat detection process S400, first, the control device 10 activates the heat sensing unit 70 as the activation process (S70). The activation condition of the heat sensing unit 70 is, for example, when the shielding door D1 is closed. The heat sensing unit 70 senses the movement of the heat source for a predetermined time after the shielding door D1 is closed. The predetermined time for the heat sensing unit 70 to detect the movement of the heat source is, for example, 3 minutes or more and 5 minutes or less. The heat sensing unit 70 causes the recording unit 18 to record a result such as the number of moved heat sources, that is, the number of subjects C. The control device 10 shifts to the next process after a predetermined time has elapsed.

Subsequently, as a heat source determination process (S72), the determination unit 40 determines whether or not the target person C in the irradiation chamber 3 is detected or not by the heat sensing unit 70. The determination unit 40 determines based on the occupancy information of the recording unit 18. When the heat sensing unit 70 determines that the movement of the heat source is not detected in the irradiation chamber 3, the control device 10 shifts to the next process. When the heat sensing unit 70 determines that the movement of the heat source is not not detected in the irradiation chamber 3, the irradiation prohibition flag in the irradiation control unit 16 remains ON. The control device 10 executes the heat source determination process (S72) again after a predetermined time.

When the determination unit 40 determines in the heat source determination process (S72) that the number of subjects C in the irradiation chamber 3 is the initial value, the irradiation prohibition flag in the irradiation control unit 16 is turned off. Subsequently, as an irradiation process (S74), the control device 10 irradiates the neutron beam N via the neutron beam irradiation unit 2. The irradiation treatment (S74) is the same treatment as the irradiation treatment (S30) of the first embodiment.

As described above, according to the neutron capture therapy system 1B of the present embodiment, it is possible to improve the certainty of detection of the subject C who is a person other than the patient S (irradiated body) in the irradiation chamber 3. It is possible to suppress the occurrence of the event that the subject C remains in the irradiation chamber 3 during the irradiation of the neutron beam N, and to suppress the interruption of the irradiation of the neutron beam N to the patient S. Further, according to the heat sensing unit 70, the subject C in the irradiation chamber 3 can be directly sensed. Therefore, the determination unit 40 can easily determine whether or not the subject C in the irradiation chamber 3 is not detected. Further, according to the heat sensing unit 70, even when the patient S (irradiated body) arranged in the irradiation room 3 moves, the patient S (irradiated body) is the subject in the irradiation room 3. False detection as C is suppressed. Therefore, the determination unit 40 can determine with high accuracy whether or not the subject C in the irradiation chamber 3 is not detected.

<Modification example>
Although various exemplary embodiments have been described above, various omissions, substitutions, and changes may be made without being limited to the above-mentioned exemplary embodiments. For example, the target person C in the irradiation chamber 3 may be detected by using an optical camera provided in the irradiation chamber 3. In this case, the target person C may be detected in the image or the video taken by the optical camera based on the visual inspection by the administrator or the image analysis by the control device 10.

Further, the detection unit 20 is any two of the reception unit 30 of the first embodiment, the detector 50 and the estimation unit 60 of the second embodiment, the heat sensing unit 70 of the third embodiment, and the optical camera. By combining the above, the detection of the subject C in the irradiation chamber 3 may be performed. In this case, when the determination unit 40 does not determine that the target person C in the irradiation chamber 3 is not detected in all the detection results by the detection unit 20 (that is, the target person C is detected even by one person). The irradiation control unit 16 does not irradiate the neutron beam N by the neutron beam irradiation unit 2.

The front door detection set 53 and the rear door detection set 54 of the first embodiment may both be in the same room. If the subject C can be detected, it may be in the preparation room 4 or the communication room 14. The light emitter 51 of the second embodiment may be connected to the estimation unit 60.

1,1A, 1B ... Neutron capture therapy system, 2 ... Neutron beam irradiation unit, 3 ... Irradiation room, 3a ... Shielded space, 3b ... Doorway, 4 ... Preparation room, 6 ... Control room, 7 ... Accelerator, 8 ... Neutron beam Generation unit, 8a ... Deceleration material, 8b ... Shield, 10 ... Control device, 11 ... Charged particle beam generation chamber, 12 ... Beam transport path, 14 ... Communication room, 15 ... Treatment table, 16 ... Irradiation control unit, 17 ... Operation control unit, 18 ... Recording unit, 20 ... Detection unit, 30 ... Reception unit, 31 ... Door front reception unit, 32 ... Door rear reception unit, 33 ... Open / close button, 40 ... Judgment unit, 50 ... Detector, 51 ... Light emitter, 52 ... Receiver, 53 ... Door front detection set, 54 ... Door rear detection set, 60 ... Estimator, 70 ... Heat sensing unit, 71 ... Top surface heat sensing unit, 72 ... Side heat sensing unit, D1 ... Shielding Door, D2 ... Door, N ... Neutron beam, P ... Charged particle beam, S ... Patient, T ... Target, W, W1, W2, W3 ... Shielding wall.

Claims (7)

A neutron capture therapy system that irradiates the irradiated body with neutron rays.
Surrounded by a shielding wall that blocks the radiation of the neutron beam from the room to the outside, an irradiation room for arranging the irradiated body indoors and irradiating the neutron beam,
A neutron irradiation unit that irradiates the neutron beam into the irradiation chamber,
A detection unit that detects a target person who is a person other than the irradiated body in the irradiation room,
A control unit that does not irradiate the neutron beam irradiation unit with the neutron beam unless the detection unit detects the target person in the irradiation chamber.
A neutron capture therapy system. The detector is
A reception unit that accepts an input from the subject to enter the irradiation room and an input to leave the irradiation room.
Based on the input of the reception unit, a determination unit for determining whether or not the target person in the irradiation chamber is not detected, and a determination unit.
The neutron capture therapy system according to claim 1. Further provided with a shielding door for closing the doorway provided on the shielding wall,
The neutron capture therapy system according to claim 2, wherein the control unit controls the opening and closing of the shielding door based on the input of the reception unit. The detector is
A detector having a light emitter that emits light and a receiver that receives light from the light emitter,
Based on the detection result of the detector, a determination unit for determining whether or not the target person is not detected in the irradiation chamber, and a determination unit.
The neutron capture therapy system according to any one of claims 1 to 3. The detector is
With the plurality of the detectors
An estimation unit that estimates the presence of the subject in the irradiation chamber based on the detection results of the plurality of detectors.
The neutron capture therapy system according to claim 4. The detector is
A heat sensing unit that senses the movement of the heat source in the irradiation chamber,
A determination unit that determines whether or not the target person is not detected in the irradiation chamber based on the result of detection by the heat sensing unit.
The neutron capture therapy system according to any one of claims 1 to 5. The neutron capture therapy system according to claim 6, wherein the heat sensing unit senses the movement of the heat source in the irradiation chamber except at least the place where the irradiated body is arranged.

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