JP7217642B2 - Neutron capture therapy system - Google Patents

Description

The present disclosure relates to neutron capture therapy systems.

Patent Literature 1 describes a neutron capture therapy system used for neutron capture therapy (NCT: NEUTRON CAPTURE THEPARTY). In NCT treatment using this system, first, a drug is administered to the patient. This drug contains a substance that reacts with neutrons such as ¹⁰ B, and has the property of being selectively taken up by cancer cells to be treated. Then, when a patient to whom the drug is administered is irradiated with neutron beams, the neutron beam reacts with the reactant taken up by the patient's cancer cells to generate heavy charged particles. Only cancer cells are selectively destroyed by scattering of these heavy charged particles.

JP 2017-042310 A

By the way, there is a need to improve the certainty that neutron beam irradiation is performed in a state where people other than the subject (patient) to be irradiated (for example, workers such as doctors and radiological technologists) have left the room. However, since detection of whether or not a person other than the object to be irradiated 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 detecting a person other than an object to be irradiated in an irradiation room.

One aspect of the present invention is a neutron capture therapy system that irradiates an object to be irradiated with a neutron beam. This neutron capture therapy system is surrounded by a shielding wall that blocks neutron radiation from indoors to outdoors. A neutron beam irradiation unit that irradiates a neutron beam, a detection unit that detects a target person other than a person to be irradiated in the irradiation room, and a neutron beam unless the target person in the irradiation room is not detected by the detection unit. and a control unit that does not cause the irradiation unit to irradiate a neutron beam.

In this neutron capture therapy system, an object to be irradiated is placed in an irradiation chamber. When a target person who is a person other than the object to be irradiated is in the irradiation room, it is detected by the detection unit. The control unit does not cause the neutron beam irradiation unit to irradiate the neutron beam unless the detection unit does not detect the subject in the irradiation room. When the target person in the irradiation chamber is not detected by the detection unit, the neutron beam irradiation unit starts irradiating the object to be irradiated with neutron beams. Therefore, based on the result of detection by the detection unit, the subject can be made to leave the irradiation room, and then neutron beam irradiation by the neutron beam irradiation unit can be started. Therefore, it is possible to improve the certainty of detecting a person other than the object to be irradiated in the irradiation chamber.

In addition, the detection unit includes a reception unit that receives input from the subject to enter the irradiation room and to leave the irradiation room, and based on the input from the reception unit, whether or not the subject in the irradiation room is in a non-detectable state. and a determination unit that determines whether According to such a detection unit, when the reception unit inputs that the target person enters or leaves the room, the determination unit determines whether or not the target person in the irradiation room is not detected. Therefore, the detection unit can easily detect the target person in the irradiation room.

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

Further, the detection unit includes a detector having a light emitter that emits light and a light receiver that receives light from the light emitter, and based on the detection result of the detector, whether or not the target person in the irradiation room is undetected. and a determination unit that determines the Such a detector can automatically detect the movement of a subject entering and leaving a room by using light. Therefore, the determination unit can easily determine whether or not the subject in the irradiation room is detected without restricting the movement of the subject.

Also, the detection unit has a plurality of detectors and an estimation unit that estimates the presence of the subject in the irradiation room based on the detection results of the plurality of detectors. According to such an estimating unit, by estimating whether the target person is moving in the direction of entering the room or moving in the direction of leaving the room based on the difference in detection timing of a plurality of detectors, the target in the irradiation room It is possible to presume the existence of a person. In addition, since the object to be irradiated enters the room while being placed on a large treatment table compared to the object, a plurality of detectors react simultaneously. Therefore, the estimating unit can estimate the presence of the target person in the irradiation room after distinguishing between the target person entering or leaving the irradiation room and the irradiated body or object other than the target person. Therefore, the determination unit can determine with high accuracy whether or not the subject in the irradiation room is detected.

Further, the detection unit includes a heat sensing unit that senses movement of the heat source in the irradiation chamber, and a determination unit that determines whether or not the target person in the irradiation room is undetected based on the result of sensing by the heat sensing unit. have. Such a heat sensing unit can directly sense a subject in the irradiation room. Therefore, the determination unit can easily determine whether or not the subject in the irradiation room is detected.

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

According to the neutron capture therapy system of the present invention, it is possible to improve the certainty of detecting people other than the object to be irradiated in the irradiation room.

FIG. 1 is a plan view schematically showing the neutron capture therapy system according to the first embodiment. FIG. 2 is a flow chart showing a process of detecting a subject in the irradiation room according to the first embodiment. FIG. 3 is a flow chart showing a process of detecting a subject in the irradiation room 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 flow chart showing a process of detecting a subject in the irradiation room 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 a sensing range of a heat sensing portion according to the third embodiment. FIG. 8 is a flow chart showing a process of detecting a subject in the irradiation room according to the third embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference numerals, and overlapping descriptions are omitted. An XYZ coordinate system is set in each drawing, and X, Y, and Z are used to describe the positional relationship of each component. Here, the X-axis is the emission direction of the neutron beam N emitted from the neutron beam generator 8, and the Z-axis is perpendicular to the floor surface. Moreover, the Y-axis is a direction perpendicular 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>
A neutron capture therapy system is a device that performs cancer therapy using boron neutron capture therapy (BNCT). In neutron capture therapy, cancer treatment is performed by irradiating a patient (an example of an irradiated subject) to whom boron ( ¹⁰ B) is administered with neutron beams.

FIG. 1 is a plan view schematically showing the neutron capture therapy system according to the first embodiment. As shown in FIG. 1, the neutron capture therapy system 1 includes a neutron beam irradiation unit 2 for generating and irradiating therapeutic neutron beams N, and a neutron beam N to a patient S (an example of an object to be irradiated). An irradiation room 3 for irradiation, a control device 10 for controlling the irradiation of the neutron beam N in the neutron beam irradiation unit 2, and a detection unit for detecting a subject C who is a person other than the patient S in the irradiation room 3. 20 and. The subject C is, for example, a worker who places 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 can include a preparation room 4 for preparing for irradiation and a control room 6 for managing work processes.

The neutron beam irradiation unit 2 is configured to generate neutron beams N in the irradiation room 3 and irradiate the patient S with the neutron beams N. As shown in FIG. The neutron beam irradiation unit 2 includes an accelerator 7 such as a cyclotron, a neutron beam generation unit 8 that generates neutron beams N from the 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 inside the charged particle beam generation chamber 11 . The charged particle beam generation chamber 11 is a closed space covered with a shielding wall W made of concrete.

The accelerator 7 accelerates charged particles, which are protons, to generate and emit charged particle beams P, which are proton beams. The accelerator 7 has, for example, the ability to generate a charged particle beam P with a beam radius of 40 mm and 60 kW (=30 MeV×2 mA).

The beam transport path 12 emits the charged particle beam P to the neutron beam generator 8 . The beam transport path 12 has one end connected to the accelerator 7 and the other end 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 section, a current monitor, and a charged particle beam scanning section, if necessary. The beam adjustment unit controls the direction of travel of the charged particle beam P and the beam diameter. The current monitor measures the current value of the charged particle beam P (that is, charge, irradiation dose rate) 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 generator 8 includes a target T for generating neutron beams N, a moderator 8a for moderating the neutron beams N, and a shield 8b. The moderator 8a and shield 8b constitute a moderator.

Here, the neutron beams N generated in the neutron beam generator 8 include fast neutron beams, epithermal neutron beams, thermal neutron beams and gamma rays. Of these, thermal neutrons mainly react with boron taken into the tumor in the body of the patient S to exert an effective therapeutic effect. Part of the epithermal neutrons contained in the beam of neutrons N is also decelerated in the body of the patient S to become thermal neutrons that exhibit the above therapeutic effect. A thermal neutron beam is a neutron beam with an energy of 0.5 eV or less.

The target T generates a neutron beam N upon being irradiated with a charged particle beam P. As shown in FIG. The target T is made of beryllium (Be), for example, and has a disc shape with a diameter of 160 mm.

The moderator 8a decelerates the neutron beam N emitted from the target T. As shown in FIG. The neutron beam N that has been moderated by the moderator 8a and reduced to a predetermined energy is also called 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 according to various conditions such as the energy of the charged particle beam P.

For example, when the output from the accelerator 7 is a 30 MeV proton beam and a beryllium target is used as the target T, the material of the moderator 8a can be 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 fluenthal (trade name; aluminum, aluminum fluoride, lithium fluoride (mixtures 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 fluenthal.

The shield 8b shields neutron beams N and radiation such as gamma rays generated by the generation of the neutron beams N from being emitted to the outside. At least 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 via a communication room 14 .

The irradiation room 3 is a room in which the patient S is placed 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. The size of the irradiation chamber 3 is, for example, 3.5 m wide×5 m deep×3 m high. The irradiation chamber 3 is composed of a shielded space 3a surrounded by a shield wall W2, a doorway 3b through which the patient S enters and exits, and a shielded door D1 that opens and closes the doorway 3b.

The shielding wall W2 forms the shielding space 3a. In this shielded space 3a, radiation is prevented from entering from the outside of the irradiation chamber 3 into the room, and from the inside to the outside of the room. That is, the shielding wall W2 blocks radiation of the neutron beams N from the interior of the irradiation chamber 3 to the exterior. The shielding wall W2 is formed integrally with the shielding wall W that defines the charged particle beam generation chamber 11 . The shielding wall W2 is a concrete wall with a thickness of 2 m or more. A shield wall W<b>1 separating 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 part of the shielding wall W. As shown in FIG.

A doorway 3b is provided in a part of the shielding wall W2. A shielding door D1 is arranged at the entrance 3b. The shield door D1 is for suppressing radiation in the shield space 3a from being radiated to the connecting room 14. As shown in FIG. 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 heavy, a high-torque motor, a speed reducer, etc. are used for the mechanism for driving the shielding door D1.

The preparation room 4 is a room for performing preparation 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 and the patient S with each other. The treatment table 15 is, for example, a movable 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 separating the preparation room 4 and the irradiation room 3 is provided between the preparation room 4 and the irradiation room 3 . The thickness of the shielding wall W3 is, for example, 3.2 m. That is, the preparation room 4 and the irradiation room 3 are separated by 3.2 m along the Y-axis direction.

Note that the preparation room 4 may be used as a room for other purposes. The preparation room 4 may be a shielded space surrounded by shielding walls W like the irradiation chamber 3, or may be a non-shielding space not surrounded by the shielding walls W. As shown in FIG.

The shielding wall W3 is provided with a communication chamber 14 communicating from the preparation chamber 4 to the irradiation chamber 3 . The communication room 14 is a room for moving the treatment table 15 on which the patient S is restrained between the preparation room 4 and the irradiation room 3 . The size of the communication room 14 is, for example, 1.5 m wide×3.2 m deep×2.0 m high. A door D2 is arranged between the preparation room 4 and the communication room 14. - 特許庁

The control room 6 is a room for managing the entire process performed using the neutron capture therapy system 1 . A manager enters the management room 6 and manages the overall process using a control device 10 for operating the neutron beam irradiation unit 2 arranged in the management 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 Only Memory), 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 circuits are mounted. The CPU, ROM, RAM, A/D conversion circuit, D/A conversion circuit, and communication I/F circuit are connected to the bus. Note that the A/D conversion circuit and the D/A conversion circuit are connected to a bus through an input/output I/F circuit.

The control device 10 has an irradiation control section 16 (an example of a control section), an operation control section 17 , a recording section 18 and a determination section 40 . The recording unit 18 and the determination unit 40 are included in the detection unit 20 . The detection unit 20 detects the subject C within the irradiation room 3 .

The irradiation control unit 16 controls the start and stop of the neutron beam N irradiation based on instructions from the administrator. For example, the administrator commands the start and stop of the neutron beam N irradiation by operating a screen displayed on a touch panel connected to the control device 10 . Also, the irradiation control unit 16 controls the start and stop of 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 start irradiation of the neutron beam N, to the neutron beam irradiation unit 2, the neutron beam irradiation unit 2 causes the neutron beam N to enter the irradiation chamber 3. Irradiate. For example, 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, so that the neutron beam irradiation unit 2 causes the neutron beam N to enter the irradiation chamber 3. stop irradiation.

Here, in the neutron capture therapy, currently, one patient S is irradiated with the neutron beam N only once. 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. On the other hand, if the neutron beam N is irradiated while the subject C remains in the irradiation chamber 3, the neutron beam N irradiation must be interrupted. Therefore, by improving the certainty of detection of the subject C in the irradiation room 3, the occurrence of the event that the subject C remains in the irradiation room 3 during the irradiation of the neutron beam N is suppressed, and the patient S It is possible to suppress the interruption of the irradiation of the neutron beam N to

Specifically, the irradiation control unit 16 prevents the neutron beam irradiation unit 2 from irradiating the irradiation chamber 3 with the neutron beam N unless the detection unit 20 does not detect the subject C in the irradiation chamber 3 . The irradiation control unit 16 is in a state where the neutron beam irradiation unit 2 does not irradiate the neutron beam N unless the above conditions are satisfied, regardless of what other conditions are satisfied. Even if the above conditions are satisfied, the irradiation control unit 16 may allow the neutron beam irradiation unit 2 to irradiate the neutron beam N after satisfying other conditions.

A technique in which the irradiation control unit 16 prevents the irradiation chamber 3 from being irradiated 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 that the neutron beam irradiation unit 2 does not generate the neutron beams N. FIG. For example, the irradiation control unit 16 does not have to accept a command from an administrator. In this case, the irradiation control unit 16 does not display an option to start irradiation with the neutron beam N on the screen displayed on the touch panel operable by the administrator unless the above conditions are satisfied. Further, the irradiation control unit 16 does not have to generate the irradiation start signal to be transmitted to the neutron beam irradiation unit 2 even if the command from the administrator is received. Even when the irradiation start signal is generated, the irradiation control unit 16 blocks the signal before it is transmitted to the neutron beam irradiation unit 2 for control reasons.

When the neutron beam irradiation unit 2 receives the irradiation start signal, the irradiation control unit 16 may control the mechanism of the neutron beam irradiation unit 2 so as not to generate the neutron beam N in the irradiation chamber 3. . For example, the irradiation control unit 16 prevents the irradiation chamber 3 from being irradiated with the neutron beam N in at least one of generation or irradiation of the charged particle beam P in the accelerator 7 and transportation of the charged particle beam P in the beam transport path 12. 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 8 b of the neutron beam generation unit 8 . The irradiation control unit 16 may use another neutron beam N shielding mechanism provided in the neutron beam irradiation unit 2 to regulate the generation of the neutron beams N in the irradiation chamber 3 .

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 is allowed to irradiate the neutron beam N”. This switching is performed when the subject C in the irradiation room 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 detection unit 20 does not detect the subject C in the irradiation room 3, the irradiation prohibition flag is turned ON. When the irradiation prohibition flag is ON, irradiation is regulated by control as described above, or is mechanically regulated. When the detection unit 20 does not detect the subject C in the irradiation room 3, 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 in accordance with the administrator's instruction, so that the neutron beam irradiation unit 2 emits neutron beams into the irradiation chamber 3. Irradiate with N.

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

The recording unit 18 records the presence information of the subject C in the irradiation room 3 detected by the detection unit 20 . The in-room information includes at least one of information that can identify the individual of the subject C and the number of the subjects C in the irradiation room 3 . The room presence information in 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, or the like. The reception unit 30 receives an input from the subject C to enter the irradiation room 3 and an input to exit from the irradiation room 3 . The control device 10 records the presence-in-room information in the recording unit 18 based on the input received by the receiving unit 30 . Note that the reception unit 30 may directly record the room presence information in the recording unit 18 .

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

When the reception unit 31 in front of the door is a card reader, the subject C holds an ID card corresponding to the reception unit 31 in front of the door one-on-one with the subject C to enter or leave the irradiation room 3. can be entered. For example, when the ID card is held over the reception unit 31 in front of the door for an odd number of times, it is input to enter the irradiation room 3. input to the effect that

When the front reception unit 31 is a touch panel, for example, the front reception unit 31 displays an option to enter the irradiation room 3 or to exit from the irradiation room 3 on the screen. The subject C selects an option displayed in the reception section 31 in front of the door to enter the irradiation room 3 or leave the irradiation room 3 .

When the reception unit 31 in front of the door is a button, for example, the subject C selects and presses a button for entering the irradiation room 3 or a button for exiting the irradiation room 3 provided in the reception unit 31 in front of the door. Thus, an input to enter the irradiation room 3 or an input to exit from the irradiation room 3 can be made. As for the format of the front door reception unit 31, for example, two or more of a card reader, a touch panel, buttons, or the like may be used together.

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

Specifically, when at least one subject C enters the room into the reception unit 30 and does not leave the room through the reception unit 30, the presence information is It indicates that at least one subject C remains. In this case, the determination unit 40 determines that the subject C is not detected in the irradiation room 3 (that is, even one subject C is detected). In this case, the irradiation control unit 16 turns ON the irradiation prohibition flag based on the determination result of the determination unit 40 and prevents the neutron beam N from being irradiated by the neutron beam irradiation unit 2 .

In addition, when all the subjects C enter the room at the reception unit 30 and leave the room at the reception unit 30, the room presence information indicates that all the subjects C have left the room and the irradiation This indicates that there is no subject C left in the room 3. In this case, the determination unit 40 determines that the subject C is not detected in the irradiation room 3 . The irradiation control unit 16 turns off the irradiation prohibition flag based on the determination result of the determination unit 40 and causes the neutron beam irradiation unit 2 to irradiate the neutron beam N. FIG. Note that the determination unit 40 may make a determination by referring to only the number of people in the room from the room occupancy information. A judgment may be made.

When the in-room information indicates that at least one subject C is present in the irradiation room 3, the operation control unit 17 opens the shielding door D1. Since the neutron beam N is not irradiated while the subject C is present in the irradiation chamber 3, the irradiation control unit 16 does not perform the neutron beam N irradiation while the shield door D1 is open. do not have. Further, when the in-room information indicates that all the subjects C are not present in the irradiation room 3, the operation control unit 17 closes the shield door D1. 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 performs the neutron beam N irradiation with the shield door D1 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 from the reception unit 30 to enter the irradiation chamber 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 formats of the front reception part 31 are used together, unless the input to enter the irradiation room 3 or the input to exit from the irradiation room 3 in each model does not match, the reception part 31 in front of the door or the front reception part 31 The determination unit 40 does not have to accept the input by the subject C.

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

Subsequently, as room entry recording processing ( S<b>4 ), the control device 10 records room presence information in the recording unit 18 based on the input of the subject C in the reception unit 31 in front of the door. At this time, the presence-in-room information indicates that at least one subject C, who has entered the reception section 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 of the subject C to enter the irradiation room 3 in the door front receiving unit 31. After entering the irradiation room 3 , the subject C performs actions within the irradiation room 3 . Subsequently, as an exit input process (S22), the reception unit 31 in front of the door receives an input from the subject C to the effect that he/she is to exit the irradiation room 3. FIG.

Subsequently, as the room leaving recording process (S24), the control device 10 records the room presence information in the recording unit 18 based on the input of the subject C in the reception unit 31 in front of the door. At this time, the in-room information indicates that the target person C, who has entered the request to leave the room at the reception section 31 in front of the door, does not remain in the irradiation room 3 .

Subsequently, as room presence determination processing ( S<b>26 ), the determination unit 40 determines whether or not the subject C in the irradiation room 3 is not detected based on the room presence information of the recording unit 18 . When the recording unit 18 only has room presence information indicating that there is no subject C in the irradiation room 3, the determination unit 40 determines that the subject C in the irradiation room 3 is not detected.

In the presence determination process (S26), if the recording unit 18 has room presence information indicating that at least one subject C is present in the irradiation room 3, the determination unit 40 determines whether the subject C is detected in the irradiation room 3. It is determined that it is not in a state where it cannot be detected (that is, a state in which even one person C is detected). For example, in the case where there are a plurality of subjects C, the recording unit 18 inputs information indicating that the subject C is in the irradiation room 3 to enter the irradiation room 3 at the reception unit 31 in front of the door. This includes the case where even one of the multiple target persons who have entered the room has not entered an input to leave the room. In this case, the irradiation prohibition flag in the irradiation control unit 16 remains ON. The control device 10 performs the presence-in-room determination process (S26) again after a predetermined period of time. In this case, the control device 10 may issue a warning to the subject C or the administrator for confirmation. After that, other subjects C execute exit input processing (S22) and exit recording processing (S24). is determined.

In the room presence determination process (S26), if the determination unit 40 determines that the subject C in the irradiation room 3 is not detected, then as the door closing process (S28), the operation control unit 17 Based on the room presence information of the recording unit 18, the shielding door D1 is closed.

Subsequently, as an irradiation process ( S30 ), the control device 10 causes the neutron beam N to be irradiated through the neutron beam irradiation unit 2 . When the determination unit 40 determines that the subject C in the irradiation room 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, and enables input. Accordingly, the administrator can start irradiation of the neutron beam N by the neutron beam irradiation unit 2 after confirming by the detection unit 20 as well as by his/her own visual observation.

Refer to FIG. 1 again. The reception section 30 may further have a rear reception section 32 . The post-door receiving section 32 is provided inside the irradiation chamber 3 . The post-door reception unit 32 is, for example, a card reader, a touch panel, buttons, or a combination thereof. The post-door reception part 32 may have the same form as the front-door reception part 31 . The recording unit 18 records the presence information of the subject C in the irradiation room 3 based on the input received by the reception unit 32 behind the door. In the recording unit 18, when the room presence information input by the subject C to the front-door reception unit 31 and the back-door reception unit 32 and recorded do not match, the control device 10 confirms with the subject C or the administrator. You may issue a warning to do so. In the room presence information of the recording unit 18, all the subjects C who have entered the front reception section 31 and the rear reception section 32 have entered the reception section 31 and the reception section 32 behind the door. is input, the determination unit 40 determines that the subject C in the irradiation room 3 is not detected (that is, even one subject C is detected).

In addition, when the subject C who has entered only the reception section 31 in front of the door inputs that he/she will leave the room only in the reception section 31 in front of the door, the presence information indicates that he/she will leave the room. It is a record that was made. When the subject C, who has entered only the reception section 32 behind the door, inputs the intention to leave only the reception section 32 behind the door, the room presence information is entered by the subject C to the effect of leaving the room. record. In the room presence information of the recording unit 18, when the target person C who has entered only the reception unit 32 behind the door is recorded, the control device 10 notifies, for example, an abnormality. The control device 10 may notify the target person C of information and prompt him or her to enter the room at the reception section 31 in front of the door.

When the target person C who has entered the irradiation chamber 3 inputs that he/she has entered the irradiation chamber 3 in the post-door reception unit 32, the operation control unit 17 closes the shield door D1. In the reception unit 32 after the door, the operation control unit 17 opens the shield door D1 when the subject C who leaves the irradiation room 3 inputs the intention of leaving the room.

A second reception process, which is a process in which the subject C enters the irradiation room 3 and then leaves the irradiation room 3 when the reception part 30 further includes the reception part 32 after the door, will be described. FIG. 3 is a flow chart showing a process of detecting a subject in the irradiation room according to the first embodiment. As shown in FIG. 3, the second receiving process S200 includes the same processes as the first receiving process S100. The control device 10 in the second reception process S200 first 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, an entry completion input process (S10), an entry completion record process (S12), a door entry It has blockage processing (S14), exit start input processing (S16), exit start recording processing (S18), and exit door opening processing (S20) in this order.

As the entry completion input process (S10), the post-door reception unit 32 installed in the irradiation room 3 receives input from the subject C indicating that he/she has entered the irradiation room 3. FIG. Subsequently, as room entry completion recording processing ( S<b>12 ), the control device 10 records room presence information in the recording unit 18 based on the input of the subject C in the reception unit 32 behind the door. Subsequently, as door closing processing when entering a room (S14), the operation control unit 17 closes the shielding door D1 based on the room presence information of the recording unit . As a result, the subject C who does not make an input at the reception section 31 in front of the door is prevented from entering the irradiation room 3 . After entering the irradiation room 3 , the subject C performs actions within the irradiation room 3 .

As the leaving start input process (S16), the post-door reception unit 32 installed in the irradiation room 3 receives an input from the subject C to leave the irradiation room 3. FIG. Subsequently, as the leaving start recording process ( S<b>18 ), the control device 10 records the room presence information in the recording section 18 based on the input of the subject C in the reception section 32 behind the door. Subsequently, as door opening processing when leaving the room (S20), the operation control unit 17 opens the shielding door D1 based on the room presence information of the recording unit . In the reception section 31 in front of the door, even if the shielding door D1 is closed when another subject C inputs an instruction to leave the irradiation room 3, the subject C in the irradiation room 3 can receive reception after the door. In section 32, it is possible to input to the effect that the user wants to leave the room. This prevents the subject C from remaining in the irradiation room 3 .

Subsequently, the control device 10 in the second reception process S200 executes the same processing as the room exit input process (S22) and the room exit recording process (S24) in the first reception process S100. Subsequently, as room presence determination processing ( S<b>26 ), the determination unit 40 determines whether or not the subject C in the irradiation room 3 is not detected based on the room presence information of the recording unit 18 . When the recording unit 18 has room presence information indicating that no subject C is present in the irradiation room 3 , the determination unit 40 determines that the subject C is not detected in the irradiation room 3 . In the occupancy information of the recording unit 18, all the subjects C who have entered the front reception part 31 and the rear reception part 32 enter the entry to the front reception part 31 and the rear reception part 32 to leave the room. If it is recorded, the determination unit 40 determines that the subject C in the irradiation room 3 is not detected.

In the presence determination process (S26), if the recording unit 18 has room presence information indicating that the subject C is present in the irradiation room 3, the determination unit 40 determines whether the subject C is not detected in the irradiation room 3. It is determined that there is none (that is, even one person C is detected). In the room occupancy information of the recording unit 18, when the subject C has not entered the input to at least one of the front reception unit 31 and the rear reception unit 32 to leave the room, the determination unit 40 performs irradiation. It is determined that the subject C in the room 3 is not detected. In this case, the control device 10 performs the presence-in-room determination process (S26) again after a predetermined time. In this case, the control device 10 may issue a warning to the subject C or the administrator to confirm. Thereafter, at least one set of exit start input processing (S16) and exit start recording processing (S18) or exit input processing (S22) and exit recording processing (S24) is executed by the other subject C, and presence determination is performed. In the process (S26), it is determined whether or not all the subjects C have left the irradiation room 3 again. The control device 10 omits the processing that has already been performed by another subject C as appropriate.

In the room presence determination process (S26), if the determination unit 40 determines that the subject C in the irradiation room 3 is not detected, then in the second reception process S200, the control device 10 performs the first reception The same process as the door closing process (S28) and the irradiation process (S30) in 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 room 3 . It is possible to suppress the occurrence of the event that the subject C remains in the irradiation room 3 during the irradiation of the neutron beam N, and to suppress the interruption of the irradiation of the patient S with the neutron beam N. Further, when the reception unit 30 inputs that the subject C is entering or leaving the room, the determination unit 40 determines whether or not the subject C is detected in the irradiation room 3 . Therefore, the detection unit 20 can easily detect the subject C in the irradiation room 3 . Also, the subject C in the irradiation room 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 room 3 is detected.

<Second embodiment>
Next, the neutron capture therapy system 1 according to the second embodiment will be explained. In the description of this embodiment, differences from the first embodiment will be described, and redundant description will be omitted. The neutron capture therapy system 1A according to the second embodiment is different from the neutron capture therapy system 1 according to the first embodiment in that the detection unit has a detector and an estimation unit, and the determination unit is based on the estimation result of the estimation unit. The difference is that it is determined whether or not the target person in the irradiation room is not detected based on the above.

The detection unit 20 has a detector 50 . The sensing unit 20 can have an estimating 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 or the like, and detects the subject C in the irradiation room 3 . That is, the detector 50 is provided at a place through which 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, near the shield door D1.

Detector 50 is, for example, a laser sensor. The detector 50 has a light emitter 51 that emits light and a light receiver 52 that receives the light from the light emitter 51 . The light emitted by the light emitter 51 is, for example, laser. The light emitter 51 and the light receiver 52 are spaced apart so that a passing object 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 line of flow of the subject C intersect. The light-emitting device 51 and the light-receiving device 52 are provided at positions where it is easy to discriminate between the subject C and other passing objects. The light emitter 51 and the light receiver 52 are provided, for example, at a height where 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 .

Light emitted from the light emitter 51 is blocked by a passing object such as the treatment table 15 or the subject C, so that the light receiver 52 does not receive the light. At least the photodetector 52 transmits to the estimator 60 a light shielding start time, which is the time when the light begins to be shielded, and a light shielding end time, which is the time when the light begins to be received again. The light receiver 52 may directly measure the light shielding elapsed time, which is the light shielding time, and transmit it to the estimator 60 .

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

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

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

The moving direction of the passing object in the estimation unit 60 may be estimated by comparing the light blocking end times. That is, when the light shielding end time in the door front detection set 53 is earlier than the light shielding end time in the door rear detection set 54 , the estimation unit 60 estimates that the passing object has entered the irradiation chamber 3 . When the light shielding end time in the door front detection set 53 is later than the light shielding end time in the door rear detection set 54 , the estimation unit 60 estimates that the passing object has left the irradiation chamber 3 .

If the estimation results of the moving direction of the passing object obtained from 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 light shielding end time of another combination of the light emitter 51 and light receiver 52. By using it, the moving direction of the passing object may be estimated. Based on the direction of movement, the estimation unit 60 estimates the number of subjects C who have entered the irradiation room 3 and have not left the room.

Based on the detection results obtained from the front door detection set and the rear door detection set 54, the estimation unit 60 estimates the presence of a passing object that has passed between the door front detection set 53 and the door rear detection set 54. . The estimating unit 60 measures the light shielding start time of the door front detection set 54 from the light shielding start time of the door front detection set 53 to the light shielding end time, and calculates the light shielding elapsed time of the door front detection set 53 or the door rear detection set 54. is longer than the light-blocking elapsed time of other passing objects, it can be estimated that the treatment table 15 enters the irradiation room 3 . The estimating unit 60 determines that when the light shielding start time of the door front detection set 53 is measured from the light shielding start time of the door front detection set 54 to the light shielding end time of the door front detection set 54 and the light shielding of the door front detection set 53 or the door rear detection set 54 is detected. If the elapsed time is longer than the light shielding elapsed time of other passing objects, it can be estimated that the treatment table 15 is leaving the irradiation room 3 .

The estimating unit 60 can estimate that the passing object is the target person C in cases other than the above. For example, when the light shielding elapsed time in the door front detection set 53 and the door rear detection set 54 is shorter than the light shielding elapsed time in the treatment table 15, the subject C is between the door front detection set 53 and the door rear detection set 54. It can be estimated that it is the effect of the feet touching the ground at the same time. The estimation unit 60 records the estimation results such as the estimated moving direction of the target person C and the number of persons in the recording unit 18 as room presence information.

Note that 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 chamber 14 . The open/close button 33 is provided at a position farther from the irradiation chamber 3 than the front door detection set 53, for example. 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 room 3 is detected based on the estimation result of the estimation unit 60 in the room presence information of the recording unit 18 .

When the in-room information indicates that at least one subject C is present in the irradiation room 3, the operation control unit 17 opens the shielding door D1. Since the neutron beam N is not irradiated while the subject C is present in the irradiation chamber 3, the irradiation control unit 16 does not perform the neutron beam N irradiation while the shield door D1 is open. do not have. Further, when the in-room information indicates that all the subjects C are not present in the irradiation room 3, the operation control unit 17 closes the shield door D1. 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 performs the neutron beam N irradiation with the shield door D1 closed.

Next, in the detector 50 and the estimation unit 60, a detection process from the subject C entering the irradiation room 3 until leaving the room will be described. FIG. 5 is a flow chart showing a process of detecting a subject in the irradiation room according to the second embodiment. In the detection process S300 shown in FIG. 5, the controller 10 first activates the light emitter 51 and the light receiver 52 as activation processing (S40). The light emitter 51 emits light. The light receiver 52 receives light from the light emitter 51 . The light emitter 51 starts irradiating a laser toward the light receiver 52, for example.

Subsequently, as a passing object determination process (S42), the determination unit 40 determines whether or not the plurality of detectors 50 have detected a passing object within a predetermined period of time. If only one detector 50 detects the passing object, the determination unit 40 does not determine that the passing object has been detected. That is, when one light receiver 52 is shielded from light and the other light receivers 52 are not shielded from light, for example, the estimation unit 60 determines that the object, not the passing object, is the light emitter 51 and the light receiver 52 It is presumed that this occurs when it is provided between When the determination unit 40 determines that a passing object has been detected, the control device 10 proceeds to the next process. When the determining unit 40 determines that no passing object has been detected, the control device 10 executes the passing object determination process (S42) again after a predetermined period of time.

Subsequently, as shielding door determination processing (S44), the determination unit 40 determines whether or not the shielding door D1 is open. The subject C intending to enter the room operates the open/close button 33 and opens the shielding door D1 before entering the irradiation room 3 . Since the passing object other than the target person 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 open, the control device 10 proceeds 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 object determination process (S42) again after a predetermined time.

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

Subsequently, as a detection determination process (S48), the estimation unit 60 determines whether or not the subject C is detected in the detector 50 in the order of the front door detection set 53 and the back door detection set 54. FIG. When the detector 50 detects the subject C in the order of the front door detection set 53 and the back door detection set 54 , the estimation unit 60 estimates that the movement direction of the subject C is the direction of entering the irradiation chamber 3 . In this case, subsequently, as count-up processing (S50), the estimation unit 60 calculates the number of subjects C in the irradiation room 3 assuming that the number of subjects C in the irradiation room 3 has increased by one. For example, when the subject C who enters 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), if the detector 50 does not detect the subject C in the order of the front door detection set 53 and the back door detection set 54, the estimation unit 60 determines that the moving direction of the subject C is the irradiation room. It is estimated that it is the direction to leave from 3. In this case, subsequently, as countdown processing (S52), the estimation unit 60 calculates the number of subjects C in the irradiation room 3 assuming that the number of subjects C in the irradiation room 3 has decreased by one. For example, when there are two subjects C who have entered the irradiation room 3, the estimation unit 60 calculates the count as "1" when the subject C who leaves the irradiation room 3 is the first person.

Following the count-up process (S50) or the count-down process (S52), the estimation unit 60 causes the recording unit 18 to record the estimation results such as the number of people as a 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 open/closed state of the shielding door D1.

Subsequently, as the number-of-persons determination process (S56), the determination unit 40 determines whether or not the number of subjects C in the irradiation room 3 is the initial value. The determining unit 40 makes a determination by comparing the room presence information of the recording unit 18 and the initial value set by the estimating unit 60 . When the determination unit 40 determines that the number of subjects C in the irradiation room 3 is the initial value, the control device 10 proceeds to the next process. When the determination unit 40 determines that the number of subjects C in the irradiation room 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 object determination process (S42) again after a predetermined period of time.

In the number-of-persons determination process (S56), when the determination unit 40 determines that the number of subjects C in the irradiation room 3 is the initial value, the irradiation prohibition flag in the irradiation control unit 16 is turned OFF. Subsequently, as an irradiation process ( S<b>58 ), the irradiation control unit 16 causes the neutron beam N to be irradiated through the neutron beam irradiation unit 2 . The irradiation process (S58) is the same process as the irradiation process (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 detecting the subject C who is a person other than the patient S (irradiated body) in the irradiation room 3 . It is possible to suppress the occurrence of the event that the subject C remains in the irradiation room 3 during the irradiation of the neutron beam N, and to suppress the interruption of the irradiation of the patient S with the neutron beam N. Further, the detector 50 can automatically detect the motion of the subject C entering and leaving the room by using light. Therefore, the determination unit 40 can easily determine whether or not the subject C in the irradiation room 3 is not detected without restricting the movement of the subject C.

Further, according to the estimating unit 60, based on the difference in the detection timing of the plurality of detectors 50, etc., by estimating whether the subject C is moving in the direction of entering the room or moving in the direction of leaving the irradiation room. 3, the presence of subject C can be inferred. In addition, since the patient S (object to be irradiated) enters the room while being placed on the treatment table 15 which is larger than the subject C, a plurality of detectors 50 react simultaneously. Therefore, the estimating unit 60 distinguishes between the subject C entering or leaving the irradiation room 3 and the patient S (irradiated body) or object other than the subject C, and The presence of C can be presumed. Therefore, the determination unit 40 can determine with high accuracy whether or not the subject C in the irradiation room 3 is detected.

<Third Embodiment>
Next, a neutron capture therapy system 1B according to a third embodiment will be described. In the description of this embodiment, differences from the second embodiment will be described, and redundant description will be omitted. The neutron capture therapy system 1B according to the third embodiment is different from the neutron capture therapy system 1 according to the first embodiment in that the detection unit has a heat sensing unit, and the determination unit is based on the result of sensing by the heat sensing unit. The difference is that it is determined whether or not the target person in the irradiation room is not detected based on the above.

The detector 20 has a heat detector. 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 room 3 and detects the subject C within the irradiation room 3 . The heat sensing unit 70 senses movement of the heat source within the irradiation chamber 3 . The heat sensing section 70 is, for example, an infrared sensor. When the heat sensing unit 70 senses the movement of the heat source, the control device 10 detects the subject C and records it in the recording unit 18 as room presence information. When the heat sensing unit 70 detects that the temperature is in a range close to human body temperature (for example, 33° C. to 43° C.) and the heat source moves, the control device 10 records it in the recording unit 18 as room occupancy information. good too.

A plurality of heat sensing units 70 may be provided to reduce blind spots. The heat sensing part 70 has, for example, a top heat sensing part 71 and a side heat sensing part 72 . The upper surface heat sensing unit 71 is provided on the upper surface of the irradiation chamber 3 and senses 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 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 a sensing range of a heat sensing portion according to the third embodiment. As shown in FIG. 7, the heat sensing unit 70 senses movement of the heat source in a range R within the irradiation chamber 3 excluding at least the place where the patient S is placed. As a result, even if the patient S placed in the irradiation room 3 moves, erroneous detection of the patient S as the subject C in the irradiation room 3 is suppressed.

Next, the heat detection process in the heat sensing unit 70 from the time when the subject C leaves the irradiation room 3 to the time when the subject C is irradiated with the neutron beam N will be described. FIG. 8 is a flow chart showing a process of detecting a subject in the irradiation room according to the third embodiment. As shown in FIG. 8, in the heat detection process S400, first, the controller 10 activates the heat sensing section 70 as activation processing (S70). A condition for activating 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 period of time after the shielding door D1 is closed. The predetermined time during which the heat sensing unit 70 senses 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 the number of moved heat sources, that is, the number of subjects C and the like. The control device 10 proceeds to the next process after the predetermined time has elapsed.

Subsequently, as a heat source determination process (S72), the determination unit 40 determines whether or not the subject C in the irradiation chamber 3 is not detected by the heat sensing unit 70. The determination unit 40 determines based on the room presence information of the recording unit 18 . When the heat sensing unit 70 determines that the movement of the heat source in the irradiation chamber 3 is not sensed, the control device 10 proceeds to the next process. When the heat sensing unit 70 determines that the movement of the heat source in the irradiation chamber 3 is not detected, 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 period of time.

In the heat source determination process (S72), when the determination unit 40 determines that the number of subjects C in the irradiation room 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 causes the neutron beam N to be irradiated through the neutron beam irradiation unit 2. FIG. The irradiation process (S74) is the same process as the irradiation process (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 room 3 . It is possible to suppress the occurrence of the event that the subject C remains in the irradiation room 3 during the irradiation of the neutron beam N, and to suppress the interruption of the irradiation of the patient S with the neutron beam N. Further, the heat sensing unit 70 can directly sense the subject C in the irradiation room 3 . Therefore, the determination unit 40 can easily determine whether or not the subject C in the irradiation room 3 is detected. Further, according to the heat sensing unit 70 , even when the patient S (irradiation object) placed in the irradiation room 3 moves, the patient S (irradiation object) can be detected as a target person 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 room 3 is detected.

<Modification>
While various exemplary embodiments have been described above, various omissions, substitutions, and modifications may be made without being limited to the exemplary embodiments described above. For example, an optical camera provided in the irradiation room 3 may be used to detect the subject C in the irradiation room 3 . In this case, the subject C may be detected based on visual observation by the administrator or image analysis by the control device 10 in the image or video captured by the optical camera.

Further, the detection unit 20 includes 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 detection unit 70 of the third embodiment, and an optical camera. The detection of the subject C in the irradiation room 3 may be performed by combining the above. In this case, regarding the case where the determination unit 40 does not determine that the target person C is not detected in the irradiation room 3 in all detection results by the detection unit 20 (i.e., even one target person C is detected) , the irradiation control unit 16 prevents the neutron beam N from being irradiated by the neutron beam irradiation unit 2 .

Both the front door detection set 53 and the rear door detection set 54 of the first embodiment may be in the same room. It may be in the preparation room 4 or the communication room 14 as long as the subject C can be detected. The light emitter 51 of the second embodiment may be connected to the estimation section 60 .

1, 1A, 1B... Neutron capture therapy system, 2... Neutron beam irradiation unit, 3... Irradiation room, 3a... Shielded space, 3b... Entrance, 4... Preparation room, 6... Management room, 7... Accelerator, 8... Neutron beam Generation unit 8a Moderator 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 Front door reception unit 32 Rear reception unit 33 Open/close button 40 Judgment unit 50 Detector 51 Light emitter 52 Light receiver 53 Door front detection set 54 Door rear detection set 60 Estimation part 70 Thermal sensing part 71 Upper surface thermal sensing part 72 Side thermal sensing part D1 Shielding Door, D2... Door, N... Neutron beam, P... Charged particle beam, S... Patient, T... Target, W, W1, W2, W3... Shield wall.

Claims (5)

A neutron capture therapy system for irradiating an object to be irradiated with a neutron beam,
an irradiation room for irradiating the neutron beam with the object to be irradiated being placed in the room, surrounded by a shielding wall for blocking radiation of the neutron beam from the room to the outside;
a neutron beam irradiation unit for irradiating the neutron beam into the room of the irradiation chamber;
a detection unit that detects a target person who is a person other than the object to be irradiated in the irradiation room;
a control unit that does not cause the neutron beam irradiation unit to irradiate the neutron beam unless the target person in the irradiation chamber is not detected by the detection unit;
a shielding door that closes an entrance provided in the shielding wall;
with
The detection unit is
It has a front-door reception part provided in a communication room connected to the irradiation room through the shielding door and a rear-door reception part provided in the irradiation room, and the target person inputs an entry to the irradiation room. and a reception unit that receives an input to leave the irradiation room;
a determination unit that determines whether or not the target person in the irradiation room is not detected based on the input from the front door reception unit and the rear door reception unit ;
has
The control unit controls opening and closing of the shielding door based on an input from the reception unit, and closes the shielding door when the post-door reception unit receives an input from the subject to enter the irradiation chamber. do,
Neutron capture therapy system. The detection unit is
a detector having an emitter for emitting light and a receiver for receiving light from the emitter;
a determination unit that determines whether or not the subject in the irradiation room is undetectable based on the detection result of the detector;
The neutron capture therapy system of claim 1 , comprising: The detection unit is
a plurality of said detectors;
an estimating unit that estimates the existence of the subject in the irradiation room based on the detection results of the plurality of detectors;
The neutron capture therapy system of claim 2 , comprising: The detection unit is
a heat sensing unit that senses movement of a heat source in the irradiation chamber;
a determination unit that determines whether or not the target person in the irradiation room is undetected based on the result of sensing by the heat sensing unit;
The neutron capture therapy system according to any one of claims 1 to 3 , having 5. The neutron capture therapy system according to claim 4 , wherein the heat sensing unit senses movement of the heat source in the irradiation chamber except at least where the object to be irradiated is placed.

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