JP7066353B2 - Treatment sleeper and radiation therapy system - Google Patents

Description

Embodiments of the present invention relate to a therapeutic bed and a radiation therapy system.

Radiation therapy can slow the growth of a tumor or shrink it by irradiating a therapeutic target, such as a tumor, to damage the DNA of the tumor cells, suppressing cell division of the tumor cells or causing cell death. It is a treatment that can be done. On the other hand, when the normal tissue is irradiated with radiation, the normal tissue may be damaged. Therefore, the treatment is performed by limiting the irradiation range so that the radiation is applied only to the treatment target.

In addition, when the treatment target is present in the chest or abdomen, the position of the treatment target in the body changes as the patient breathes. Therefore, in radiotherapy, treatment is performed by respiratory-gated irradiation or breath-holding irradiation so that the radiation is applied only to the treatment target.

Respiratory synchronous irradiation is a method of irradiating radiation at a predetermined timing in a patient's breathing. In addition, breath-holding irradiation is a method in which the patient holds his / her breath to suppress the movement of the therapeutic target and irradiates radiation during the breath-holding. By applying respiratory-gated irradiation and breath-holding irradiation, it is possible to accurately irradiate the therapeutic target. On the other hand, in respiratory synchronous irradiation, since the irradiation time of radiation at a predetermined timing at which radiation can be irradiated is short, it takes time to obtain an effective dose. In addition, breath-hold irradiation puts a heavy burden on the patient because the patient needs to hold his / her breath.

As described above, in radiotherapy, there is a demand for a method that can be treated under free breathing with less burden on the patient and in a short time.

Japanese Unexamined Patent Publication No. 2005-74156

The problem to be solved by the present invention is that by controlling the position of the top plate, the position of the treatment target can be maintained at the irradiation center (isocenter), and the treatment target can be continuously irradiated with radiation under free breathing. It is to provide a therapeutic sleeper and a radiation therapy system that can save time.

In the therapeutic sleeper of one embodiment, the position of the treatment target is held in the isocenter regardless of the change in the position of the treatment target in the patient body due to the breathing of the patient and the top plate on which the patient to be treated with radiation is placed. A control unit for controlling the position of the top plate is provided.

The schematic diagram explaining the breath-holding irradiation and the breath-holding irradiation. The conceptual block diagram which shows an example of the radiation therapy system which concerns on embodiment. The functional block diagram which shows the functional composition example of the radiotherapy system which concerns on embodiment. The flowchart which shows an example of the operation of the radiotherapy system which concerns on embodiment. Schematic diagram illustrating changes in the position of a therapeutic target with respiration. A graph explaining the amount of displacement of the body surface due to breathing and the amount of displacement of the treatment target. A graph explaining how to calculate the position of the top plate according to the amount of displacement of the body surface due to breathing. The schematic diagram explaining the control of the top plate position when irradiating a treatment target with radiation.

With reference to FIG. 1, problems in respiratory-gated irradiation and breath-holding irradiation in radiotherapy will be described. Further, after explaining the points of view of the present inventor with respect to the problem, the embodiment of the present invention will be described.

FIG. 1 is a schematic diagram illustrating respiratory synchronous irradiation and breath-holding irradiation. The upper part of FIG. 1 is a graph explaining respiratory synchronous irradiation, and the lower part of FIG. 1 is a graph explaining breath-holding irradiation. In the graph of FIG. 1, the vertical axis represents the position of the treatment target and the horizontal axis represents time.

As shown in the graph of FIG. 1, the position of the therapeutic target in the patient body changes with respiration. As shown in the upper part of FIG. 1, in respiratory synchronous irradiation, radiation is irradiated in a specific respiratory cycle in which the position of the treatment target is constant, such as at the time of maximum exhalation. In respiratory-gated irradiation, the therapeutic target can be accurately irradiated with therapeutic radiation, and the irradiation range of the radiation can be narrowed. On the other hand, since the radiation is intermittently irradiated at a predetermined timing, the treatment time becomes long.

In the breath-holding irradiation shown in the lower part of FIG. 1, the patient holds his / her breath to fix the position of the treatment target in place. Radiation is applied while the treatment target is fixed by the patient's breath hold. Unlike the case of respiratory-gated irradiation, breath-holding irradiation can continuously irradiate the patient while the patient is holding his / her breath, so that the treatment time is shorter than that of respiratory-gated irradiation. On the other hand, the patient needs to hold his / her breath while irradiating the radiation, which puts a heavy burden on the patient. In addition, in order to fix the position of the treatment target, the patient needs to adjust the position of holding the breath by himself / herself, and it may take time to fix the position of the treatment target in the predetermined position. In breath-holding irradiation, the time for irradiating the radiation is short, but there is a problem that the time required for the entire treatment is long.

Therefore, in order to solve the above problems, the present inventor moves the top plate on which the patient is placed according to the movement of the treatment target due to respiration, so that the position of the treatment target is maintained at the irradiation center (isocenter). I have come up with a structure that can be done. In the following description, in radiation therapy, an irradiation method that controls the position of the top plate according to respiration will be referred to as respiratory-synchronized sleeper-controlled irradiation. According to the breath-synchronized bed control irradiation, the radiation can be continuously irradiated under the free breathing of the patient, so that the burden on the patient can be reduced and the radiation treatment can be performed in a short time.

Hereinafter, the therapeutic bed and the radiation therapy system of the embodiment will be described with reference to the drawings.

(1) Configuration Figure 2 is a conceptual configuration diagram showing an example of a radiotherapy system according to an embodiment. As shown in FIG. 2, the radiotherapy system 1 includes a treatment planning device 10, a radiotherapy device 20, and a treatment bed 30.

The radiotherapy system 1 irradiates a subject such as patient P placed on the treatment bed 30 with radiation for treatment from the radiotherapy device 20 based on the treatment plan data generated by the treatment planning device 10. It is a treatment system to do. Further, the radiation therapy system 1 is configured to be capable of performing respiratory-synchronized sleeper control irradiation.

The treatment planning device 10 generates treatment planning data for performing radiation therapy. The treatment plan data includes treatment information items such as the position of the treatment target, the initial position of the bed, the irradiation center, the position of the patient P, the range to be irradiated, the irradiation dose, and the dose distribution. The treatment planning device 10 calculates treatment information items such as the irradiation direction of radiation, the size of the irradiation field, the irradiation dose, and the dose distribution in the body, which are necessary for creating the treatment plan data.

Further, the treatment planning device 10 determines the position of the treatment target and the irradiation range of radiation included in the treatment plan data, for example, an X-ray imaging device, an X-ray CT (Computed Tomography) device, an MRI (Magnetic Resonance Imaging) device, or the like. Identify based on the medical image obtained by the medical image diagnostic device of. The treatment planning device 10 acquires medical images from an external storage device such as PACS (Picture Archiving and Communication Systems) via a network, and creates treatment planning data. In this way, the treatment plan data is created based on the medical image acquired in advance for the patient P. Here, "in advance" means before the start of radiation therapy.

In addition to the treatment plan data, the treatment planning device 10 generates synchronization information in which the movement of the body surface accompanying the breathing of the patient used in the respiratory-synchronized sleeper control irradiation is associated with the medical image. The synchronization information may be generated as a part of the treatment plan data, or may be generated as data different from the treatment plan data. The synchronization information is generated before the start of radiation therapy as well as the treatment plan data.

The treatment planning device 10 is configured based on a computer, and can communicate with an external device via a network such as a LAN (Local Area Network). The treatment planning device 10 is composed of hardware such as a processing circuit 11, a storage circuit 12, an input device 13, and a display 14. The processing circuit 11 is interconnected to each hardware component constituting the treatment planning device 10 via a bus as a common signal transmission path.

The processing circuit 11 may be configured with dedicated hardware, or may be configured to realize various functions by software processing by a built-in processor. Here, as an example, a case where the processing circuit 11 realizes various functions by software processing by a processor will be described.

The above processors include dedicated or general-purpose CPUs (Central Processing Units), GPUs (Graphics Processing Units), application-specific integrated circuits (ASICs), programmable logic devices, and field programmable gate arrays (FPGAs). It means a circuit such as Gate Array). Examples of the programmable logic device include a simple programmable logic device (SPLD: Simple Programmable Logic Device), a compound programmable logic device (CPLD: Complex Programmable Logic Device), and the like. The processing circuit 11 realizes each function by reading and executing a program stored in the storage circuit 12 or a program directly incorporated in the processor of the processing circuit 11.

Further, the processing circuit 11 may be composed of a single processor or a combination of a plurality of independent processors. In the latter case, a plurality of storage circuits 12 corresponding to the plurality of processors may be provided, and the program executed by each processor may be stored in the storage circuit corresponding to the processor. As another example, one storage circuit 12 may collectively store programs corresponding to each function of a plurality of processors.

The storage circuit 12 is composed of, for example, a semiconductor memory element such as a RAM (Random Access Memory) and a flash memory (Flash Memory), a hard disk, an optical disk, and the like. The storage circuit 12 may be configured by a detachable circuit of a portable medium such as a USB (Universal Serial Bus) memory and a DVD (Digital Video Disk). The storage circuit 82 stores various programs executed in the processing circuit 81 (including an OS (Operating System) as well as an application program), data necessary for executing the program, and image data. Further, the storage circuit 12 may store a GUI (Graphical User Interface) program for enabling input of various commands for controlling the OS from the input device 13.

The input device 13 is a circuit for inputting a signal from an input device such as a pointing device. Here, as an example, it is assumed that the input device itself is also included in the input device 13. When the input device is operated by the operator, the input device 13 generates an input signal corresponding to the operation and outputs the input signal to the processing circuit 11. The treatment planning device 10 may include a touch panel in which the input device is integrally configured with the display 14.

The display 14 is a display device such as a liquid crystal display panel, a plasma display panel, and an organic EL (Electro Luminescence) panel. The display 14 displays an image under the control of the processing circuit 11.

The radiotherapy apparatus 20 includes a linear accelerator and generates therapeutic radiation such as X-rays, γ-rays, electron beams, proton rays, neutron rays, and heavy particle beams. Therapeutic radiation is emitted with the treatment target placed at the irradiation center (isocenter).

The radiation therapy device 20 includes a radiation source 21, a throttle 22, an arm unit 24, a high voltage power supply 26, a throttle drive device 27, a rotation drive device 28, and a treatment controller 29 as radiation irradiation means.

The radiation source 21 generates radiation.

The diaphragm 22 adjusts the irradiation range of the radiation emitted from the radiation source 21 by the diaphragm driving device 27. That is, the diaphragm drive device 27 changes the irradiation range of radiation by adjusting the opening of the diaphragm 22.

The arm portion 24 holds the radiation source 21 and the diaphragm 22 together. The arm portion 24 is configured so that the radiation source 21 and the diaphragm 22 can be integrally rotated around the patient P.

The high voltage power supply 26 supplies the power required for irradiation of radiation to the radiation source 21 under the control of the treatment controller 29.

The diaphragm drive device 27 adjusts the irradiation range of radiation by the diaphragm 22 according to the control by the treatment controller 29.

The rotation drive device 28 rotates the arm portion 24 around the connection portion 25 between the arm portion 24 and the support portion 23 under the control of the treatment controller 29.

The treatment controller 29 includes a processor and a memory such as a CPU (Central Processing Unit) (not shown), and controls the radiotherapy device 20 in an integrated manner according to the treatment plan data generated by the treatment plan device 10.

The therapeutic sleeper 30 controls the position of the top plate 31 based on the synchronization information and the movement of the body surface accompanying the breathing of the patient P in the respiratory-synchronized sleeper control irradiation.

The treatment bed 30 includes a top plate 31, a base portion 32, a bed drive device 33, and a bed controller 34. A patient P receiving radiation therapy is placed on the top plate 31.

The sleeper drive device 33 controls the position of the top plate 31 according to the control by the sleeper controller 34. Here, as an example, the device coordinate system of the therapeutic bed 30 is defined as follows. That is, the vertical direction is the Y-axis direction, the direction perpendicular to the Y-axis direction and parallel to the longitudinal direction of the top plate 31 is the Z-axis direction, and the directions perpendicular to the Z-axis direction and the Y-axis direction are the X-axis directions. ..

In the sleeper drive device 33, the top plate 31 is moved along the Y-axis direction, the top plate 31 is moved along the Z-axis direction, and the top plate 31 is moved along the X-axis direction by a motor for driving the top plate such as a stepping motor. Move in the direction. The top plate 31 can be moved simultaneously in the XYZ axis directions. The sleeper drive device 33 may move the top plate 31 in the Y-axis direction by moving the base portion 32 up and down along the Y-axis direction.

The bed controller 34 includes a processor (not shown) and a memory, and controls the treatment bed 30 in an integrated manner. In addition to controlling the position of the top plate 31, the sleeper controller 34 calculates the amount of movement of the top plate 31 according to the change in the treatment target position due to respiration. That is, the sleeper controller 34 controls the top plate 31 so that the treatment target is always located at the center of irradiation by controlling the position of the top plate 31 so that the change in the position of the treatment target due to respiration is offset. ..

Further, the body surface sensor 40 inputs the real-time body surface movement (displacement amount) of the patient P to the sleeper controller 34. The sleeper controller 34 identifies the change in the treatment target position based on the change in the position of the body surface of the patient P in real time, and calculates the position of the top plate 31. That is, the sleeper controller 34 controls the position of the top plate 31 based on the amount of fluctuation (respiratory fluctuation amount) between the top plate 31 and the treatment target, which changes according to breathing.

The body surface sensor 40 detects the amount of displacement of the body surface due to respiration. The body surface sensor 40 is composed of an infrared sensor, a camera, or the like, and measures the displacement amount of the body surface of the patient P in real time. The body surface sensor 40 is installed at a position away from the body surface of the patient P. The body surface sensor 40 is attached to, for example, the top plate 31 so that the body surface area to be measured does not change.

FIG. 3 is a functional block diagram showing a functional configuration example of the radiotherapy system 1 according to the embodiment.

The treatment planning device 10 generates treatment planning data based on the medical image of patient P. Further, the treatment planning device 10 correlates the change in the position of the body surface with the respiration of the patient P and the change in the position of the treatment target, for example, the position of the treatment target at the maximum exhalation and the position of the treatment target at the maximum inspiration. Synchronous information is generated and stored in the storage circuit 12. Synchronous information is generated prior to radiation therapy.

The medical image of patient P is acquired by a medical image diagnostic device such as an X-ray CT device or an MRI device under free breathing at rest before radiation therapy. When collecting medical images, synchronization information relating the change in the position of the body surface of the patient P and the change in the position of the treatment target is simultaneously collected.

The synchronization information is generated, for example, by associating a medical image in each phase of a medical image containing a treatment target collected in a plurality of time phases with each phase of body surface movement. The synchronization information associated with the change in the position of the body surface and the change in the position of the treatment target can identify the change in the position of the treatment target in the patient P based on the movement of the body surface. Since the process of associating the change in the position of the body surface with the change in the position of the treatment target may be the same as in the prior art, detailed description thereof will be omitted.

It should be noted that the generation of synchronization information in which the change in the position of the body surface and the change in the position of the treatment target are associated with each other is not limited to the treatment planning device 10. The bed controller 34 of the treatment bed 30 may generate synchronization information.

For example, a program for generating synchronization information is stored in the memory of the sleeper controller 34, and each part of the treatment sleeper 30 is configured so that synchronization information can be generated by executing the program by the processor of the sleeper controller 34. You may. In this case, the medical image of the patient P and the movement of the body surface collected when the medical image is taken are input to the treatment bed 30 from an external device such as the treatment planning device 10 or PACS.

As described above, the synchronization information is data in which the displacement amount of the treatment target specified from the medical image and the movement of the body surface (displacement amount of the body surface) are associated with each other. The synchronization information will be described in detail with reference to FIG. 6 described later.

The bed controller 34 of the therapeutic bed 30 has a breath-synchronized bed control function 341. The breath-synchronized sleeper control function 341 is a function realized by the processor of the sleeper controller 34 executing a program stored in the memory of the sleeper controller 34.

The respiration-synchronized sleeper control function 341 controls the position of the top plate 31 so that the position of the treatment target is held at the irradiation center (isocenter) according to the amount of displacement of the body surface of the patient P during radiotherapy. That is, the respiration-synchronized sleeper control function 341 has the top plate 31 so that the position of the treatment target is held at the irradiation center (isocenter) regardless of the change in the treatment target position in the patient due to the respiration of the patient P. Control the position.

Synchronous information and the displacement amount of the body surface of the patient P collected in real time by the body surface sensor 40 are input to the breathing synchronization type sleeper control function 341. The breathing-synchronized sleeper control function 341 calculates the position of the top plate 31 based on the real-time displacement amount of the body surface and the synchronization information.

The synchronization information includes the amount of displacement of the body surface of patient P collected in advance. The respiratory-synchronized sleeper control function 341 compares the displacement amount of the body surface of the patient P collected in advance with the displacement amount of the body surface of the patient P collected in real time, and determines whether they match. If the displacement of the patient P's body surface collected in real time matches the displacement of the patient P's body surface collected in advance, the displacement of the treatment target in the patient P's body placed on the top plate 31. Consistent with the displacement of the treatment target contained in the synchronization information. In this way, the respiratory-synchronized sleeper control function 341 identifies the displacement amount of the treatment target based on the displacement amount of the body surface of the patient P collected in real time.

Further, the respiration-synchronized sleeper control function 341 calculates the position of the top plate 31 at which the displacement of the treatment target is offset, based on, for example, the displacement amount of the treatment target that changes due to respiration. Further, the respiratory-synchronized sleeper control function 341 may calculate the amount of movement of the top plate 31 based on the amount of deviation of the position of the treatment target from the irradiation center.

The breath-synchronized sleeper control function 341 transmits the calculated position of the top plate 31 to the sleeper drive device 33, and the sleeper drive device 33 controls the position of the top plate 31. The position control of the top plate 31 by the breath-synchronized sleeper control function 341 and the sleeper drive device 33 will be described in detail with reference to FIGS. 7 and 8 described later.

(2) Operation FIG. 4 is a flowchart showing an example of the operation of the radiotherapy system 1 according to the embodiment.

Hereinafter, the operation of the radiation therapy system 1 and the treatment bed 30 according to the embodiment will be described with reference to FIGS. 5 and 6 according to the step numbers in the flowchart of FIG.

First, as a preliminary preparation, synchronization information is generated in steps S101 and S102.

In step S101, the medical image diagnostic device captures a medical image including the treatment target in the patient P's body, and the body surface sensor 40 installed in the medical image diagnostic device causes the movement of the body surface accompanying the breathing of the patient P. Be measured.

In step S102, the treatment planning device 10 identifies the treatment target from the medical image. Further, the treatment planning device 10 associates the movement of the body surface with the movement of the treatment target that changes according to the movement of the body surface accompanying respiration, and generates synchronization information.

FIG. 5 is a schematic diagram illustrating changes in the position of the treatment target with respiration. As shown in FIG. 5, the displacement amount of the body surface of the patient P is measured by the body surface sensor 40 installed at a position away from the body surface S of the patient P. FIG. 5A shows the maximum expiratory time of patient P, and FIG. 5B shows the maximum inspiratory time of patient P.

At maximum exhalation, patient P is in a state of exhalation. On the other hand, at the time of maximum inspiration, the patient P is in a state of having completely inhaled. The body surface sensor 40 measures the amount of displacement of the distance from the body surface S of the patient P to the body surface sensor 40. The displacement amount D1 at the time of maximum exhalation is larger than the displacement amount D2 at the time of maximum inspiration in a state where the chest is greatly inflated by inhaling.

The position of the treatment target in the patient P changes according to the movement of the organ with respiration. Therefore, the relative position of the treatment target with respect to the position of the top plate 31 changes with the respiration of patient P. The treatment target T1, which was on the ventral side of the patient P's chest during maximum exhalation, moves to the cranial side of the patient P's chest, as indicated by the position of the treatment target T2 during maximum inspiration. That is, the treatment target T1 moves toward the head side of the chest as the patient P inhales, and moves to the position of the treatment target T2 when the patient P has completely inhaled. On the contrary, when the patient P begins to exhale, the position of the treatment target T2 moves from the position on the cranial side of the chest toward the ventral side of the chest, and when the patient P exhales, the treatment is performed. Move to the position of the target T1. Thus, the position of the therapeutic target changes with respiration.

FIG. 6 is a graph illustrating the amount of displacement of the body surface due to respiration and the amount of displacement of the treatment target. The upper part of FIG. 6 is a graph showing changes in body surface movements due to respiration collected during medical image imaging, with the vertical axis representing the amount of displacement of the body surface and the horizontal axis representing time. The second row from the top of FIG. 6 is a graph showing the amount of displacement of the treatment target in the Z-axis direction. The vertical axis is the position of the treatment target in the Z-axis direction, and the horizontal axis is time. The third row from the top of FIG. 6 is a graph showing the amount of displacement of the treatment target in the Y-axis direction. The vertical axis is the position of the treatment target in the Y-axis direction, and the horizontal axis is time. The lowermost part of FIG. 6 is a graph showing the amount of displacement of the treatment target in the X-axis direction. The vertical axis is the position of the treatment target in the X-axis direction, and the horizontal axis is time.

The position of the treatment target of patient P changes periodically according to the movement of the body surface. For example, in the upper graph of FIG. 6, the displacement amount D1 is the displacement amount of the distance between the body surface S and the body surface sensor 40 at the time of maximum exhalation shown in FIG. 5 (a). Similarly, the displacement amount D2 is the displacement amount of the distance between the body surface S and the body surface sensor 40 at the time of maximum inspiration. The position of the treatment target in the displacement amount D1 in the Z-axis direction is ZT1, the position in the Y-axis direction is YT1, and the position in the X-axis direction is XT1. Similarly, the position of the treatment target in the displacement amount D2 in the Z-axis direction is ZT2, the position in the Y-axis direction is YT2, and the position in the X-axis direction is XT2.

As shown in FIG. 6, the synchronization information generated by the treatment planning device 10 is data in which the displacement amount of the body surface due to respiration and the displacement amount of the treatment target are associated with each other. That is, the synchronization information is data that associates the movement of the body surface with the change in the coordinates of the treatment target. Specifically, in FIG. 6, when the displacement amount on the body surface is the displacement amount D1, the coordinates of the treatment target are (XT1, YT1, ZT1).

The displacement amount of the treatment target is not limited to the coordinates, and may be a vector representing the movement direction and the movement amount of the treatment target.

As described above, the processing of steps S101 and S102 generates synchronization information in which the movement of the body surface of the patient P, which changes with respiration before the start of radiotherapy, is associated with the movement of the treatment target.

Returning to FIG. 4, the explanation of the flowchart will be continued. In the following steps S103 to S105, an operation when performing radiation therapy to the patient P will be described.

In step S103, the patient P is placed on the top plate 31 of the treatment bed 30 during the radiotherapy. In addition, the body surface sensor 40 collects the amount of displacement of the body surface of the patient P in real time.

In step S104, the breathing-synchronized sleeper control function 341 calculates the position of the top plate 31 from the displacement amount of the body surface collected in real time and the synchronization information. The position of the top plate 31 calculated by the respiratory-synchronized sleeper control function 341 is a position where the displacement amount of the treatment target due to respiration is offset and the position of the treatment target is held at the irradiation center (isocenter).

When the displacement amount of the body surface collected in real time matches the displacement amount of the body surface acquired in advance included in the synchronization information, the displacement amount of the treatment target in the patient P placed on the top plate 31 is determined. It matches the displacement of the treatment target included in the synchronization information. When the displacement amount of the body surface collected in real time matches the displacement amount of the body surface acquired in advance included in the synchronization information, the breath-synchronized sleeper control function 341 collects the displacement amount of the body surface in real time. The amount of displacement of the treatment target in the patient P can be specified based on the above. Based on the displacement amount of the treatment target thus identified, the respiratory-synchronized sleeper control function 341 calculates the position of the top plate 31 in which the change in the position of the treatment target is offset.

The breath-synchronized sleeper control function 341 transmits the position of the top plate 31 according to the displacement amount of the body surface collected in real time to the sleeper drive device 33, and notifies the radiotherapy device 20 that the treatment can be started. Send information.

In step S105, the sleeper drive device 33 moves the top plate 31 to the position of the top plate 31 received from the breathing-synchronized sleeper control function 341. In addition, the radiation therapy device 20 that has received the notification information that the treatment can be started from the breath-synchronized sleeper control function 341 starts irradiation.

It should be noted that the position control of the top plate 31 according to the movement of the body surface and the start of irradiation of radiation may be performed at the same time. In this case, the radiation therapy system 1 so that the radiation therapy device 20 that has received the notification information that the treatment can be started transmits the notification information notifying the irradiation start time to the breath-synchronized sleeper control function 341. Each part may be configured. Further, each part of the radiation therapy system 1 may be configured so that the position control of the top plate 31 according to the movement of the body surface is started first and the irradiation of radiation is started after a predetermined time has elapsed. For example, irradiation of radiation may be started several seconds after the position control of the top plate 31 is started. It should be noted that the predetermined time may be configured in each part of the radiotherapy system 1 so that the user can set it before the start of radiotherapy.

Further, the respiratory-synchronized sleeper control function 341 may monitor whether or not the displacement velocity of the body surface collected in real time matches the displacement velocity of the body surface collected in advance. For example, the respiratory-synchronized sleeper control function 341 may calculate the degree of agreement between the displacement speed of the body surface collected in real time and the displacement speed of the body surface collected in advance. The degree of coincidence is calculated, for example, by the correlation between the waveform showing the movement of the body surface collected in real time and the waveform showing the movement of the body surface collected in advance. The breath-synchronized sleeper control function 341 determines that the displacement velocity of the body surface collected in real time matches the displacement velocity of the body surface collected in advance when the degree of coincidence is within a predetermined threshold value. May be good. Each part of the radiotherapy system 1 may be configured so that the user can set a predetermined threshold value before the start of radiotherapy.

When the displacement speed of the body surface collected in real time deviates from the displacement speed of the body surface collected in advance, the respiratory synchronization type sleeper control function 341 notifies the radiation therapy device that an abnormality has occurred in respiratory synchronization. It may be configured to transmit to 20. For example, when the respiratory rate of the patient P is momentarily disturbed due to coughing or sneezing, the displacement rate of the body surface collected in real time shows a value different from the displacement rate of the body surface collected in advance. In this case, since the position of the treatment target cannot be specified from the displacement amount of the body surface collected in real time, the notification information may be transmitted to the radiotherapy device 20 so as to stop the irradiation of radiation. In this way, in order to ensure safety and avoid unnecessary exposure, when the displacement rate of the body surface collected in real time deviates from the displacement rate of the body surface collected in advance, the radiation therapy system 1 irradiates radiation. It may be configured to stop.

In the breathing synchronization type sleeper control function 341, when the degree of coincidence between the displacement speed of the body surface collected in real time and the displacement speed of the body surface collected in advance exceeds a predetermined range, an abnormality occurs in the breathing synchronization. Notification information to that effect may be transmitted to the radiotherapy device 20.

The above is the explanation of the flowchart. Hereinafter, a method of controlling the position of the top plate 31 according to the movement of the body surface will be described with reference to FIGS. 7 and 8.

FIG. 7 is a graph illustrating a method of calculating the position of the top plate 31 according to the amount of displacement of the body surface due to respiration. FIG. 7 describes a method of calculating the position of the top plate 31 in the Z-axis direction by taking the Z-axis of the treatment target as an example.

The upper part of FIG. 7 is a graph showing the movement of the body surface of the patient P collected at the time of radiotherapy in real time, the vertical axis is the displacement amount of the body surface, and the horizontal axis is time. The second row from the top of FIG. 7 is a graph showing the amount of displacement of the treatment target in the Z-axis direction. The vertical axis is the position of the treatment target in the Z-axis direction, and the horizontal axis is time. The third row from the top of FIG. 7 is a graph showing the amount of displacement of the top plate 31 in the Z-axis direction. The vertical axis is the position of the top plate 31 in the Z-axis direction, and the horizontal axis is time. The lowermost part of FIG. 7 shows the amount of displacement in the Z-axis direction in the treatment room space of the treatment target. The vertical axis is the position in the treatment room space of the treatment target in the Z-axis direction, and the horizontal axis is time.

The movement of the body surface collected in real time in the upper part of FIG. 7 corresponds to the movement of the body surface collected in advance shown in the upper part of FIG. When the movement of the body surface collected in real time matches the movement of the body surface collected in advance, the displacement amount of the treatment target in the patient P in the Z-axis direction is shown in the second row from the top of FIG. Match the graph.

The respiratory-synchronized sleeper control function 341 calculates the position of the top plate 31 in which the change in the position of the treatment target is offset based on the position of the treatment target. That is, by moving the top plate 31 in the direction opposite to the moving direction of the treatment target, the treatment bed 30 can hold the position of the treatment target at the irradiation center (isocenter).

In FIG. 7, a case where the patient P is placed on the top plate 31 so that the position ZT1 in the Z-axis direction of the treatment target is located at the isocenter at the time of maximum exhalation will be described as an example. That is, in FIG. 7, the moving direction of the treatment target and the top plate 31 will be described with the isocenter as the origin.

Z-axis position of the treatment target at maximum exhalation When ZT1 is located at the origin of the Z-axis, the position of the treatment target in the Z-axis is moved in the positive direction of the Z-axis by the inspiration of the patient P. That is, due to the inspiration of the patient P, the position of the treatment target on the Z axis moves from the position ZT1 to the position ZT2 along the positive direction of the Z axis. The respiratory-synchronized sleeper control function 341 calculates the position of the top plate 31 in the negative direction of the Z-axis where the change from the position ZT1 to the position ZT2 on the Z-axis of the treatment target is offset.

That is, the graph showing the displacement amount of the top plate 31 in the Z-axis direction is a graph obtained by inverting the graph showing the displacement amount of the treatment target with the line parallel to the horizontal axis as the axis. When the position of the treatment target on the Z axis moves from the position ZT1 to the position ZT2 along the positive direction of the Z axis, the position of the top plate 31 on the Z axis is controlled along the negative direction of the Z axis.

The sleeper drive device 33 moves the top plate 31 to a position in the negative direction of the Z axis calculated by the breathing-synchronized sleeper control function 341. As a result, as shown in the lowermost part of FIG. 7, the position of the treatment target in the Z-axis direction on the treatment room space is held at the irradiation center (isocenter).

Similarly, for the X-axis and the Y-axis, the breathing-synchronized sleeper control function 341 calculates the position of the top plate 31 on the X-axis and the Y-axis according to the displacement amount of the treatment target. The sleeper drive device 33 simultaneously moves the top plate 31 in the XYZ axis direction, and the position of the top plate 31 is always held at the irradiation center (isocenter) regardless of the position change of the treatment target due to respiration. To control.

The breathing-synchronized sleeper control function 341 may calculate not only the position of the top plate 31 but also the moving speed. That is, the breathing-synchronized sleeper control function 341 may control the sleeper drive device 33 so as to move the top plate 31 to the calculated position at a constant speed, or to the position where the top plate 31 is calculated at a different speed. The sleeper drive device 33 may be controlled so as to be moved. Specifically, at the start and end stages of exhalation or inspiration, the movement speed of the top plate 31 is made lower than in the middle stage of exhalation or inspiration, and the movement speed of the top plate 31 is slowed down during one cycle of the respiratory cycle. It may be attached and controlled.

FIG. 8 is a schematic diagram illustrating control of the position of the top plate 31 when irradiating the treatment target with radiation. The solid line shows the patient P at the maximum exhalation, and the dashed line shows the patient P at the maximum inspiration.

FIG. 8 shows that the treatment target is held at the irradiation center (isocenter) by controlling the position of the top plate 31 according to the movement of the body surface of the patient P collected in real time. In FIG. 8, similarly to FIG. 7, the position of the top plate 31 will be described by taking as an example the case where the patient P is placed on the top plate 31 so that the treatment target is located at the irradiation center (isocenter) at the time of maximum exhalation.

For example, when the patient P is inhaled, the position of the top plate 31 in the Z-axis direction moves from the position shown by the solid line under the control of the sleeper drive device 33 in the negative direction of the Z-axis according to the inspiration of the patient P. At the time of maximum intake, it moves to the position indicated by the broken line. On the contrary, at the time of exhalation of the patient P, the position of the top plate 31 in the Z-axis direction moves in the positive direction of the Z-axis according to the inspiration of the patient from the position shown by the broken line under the control of the sleeper drive device 33, and the patient P moves. At the time of maximum exhalation, the patient moves to the position indicated by the solid line. The same control is applied to the Y-axis and the X-axis of the top plate 31.

In this way, the sleeper drive device 33 moves the position of the top plate 31 shown by the solid line to the position of the top plate 31 shown by the broken line according to the movement of the patient's body surface. By controlling the position of the top plate 31 in this way, the treatment target is always present at the irradiation center (isocenter), and radiation can be continuously irradiated under free breathing.

Further, since the position of the treatment target is held by mechanical control by moving the top plate 31, the patient P only needs to be placed on the top plate 31, and the burden on the patient P is small. Further, the movement of the top plate 31 in accordance with the breathing of the patient P relaxes the patient P and contributes to the maintenance of stable breathing at rest of the patient P.

Furthermore, by using the synchronization information associated with the displacement of the body surface due to breathing collected in advance and the position of the treatment target in the body, radiation therapy is performed only with the displacement of the body surface collected in real time. It can be performed. Therefore, during radiotherapy, the treatment can be performed without acquiring an image of the inside of the body with an X-ray device or the like, so that the exposure dose can be suppressed.

According to the radiation therapy system 1 and the treatment bed 30 according to the present embodiment, the position of the treatment target is held at the irradiation center (isocenter) by controlling the position of the top plate, so that the treatment target can be used under free breathing. Radiation can be continuously applied and the treatment time can be shortened.

The correspondence between the terms of the claims and the embodiments is as follows, for example. The correspondence shown below is an interpretation shown for reference only, and does not limit the present invention.

The respiratory-synchronized sleeper control function 341 of the embodiment is an example of the control unit according to claim.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Radiation therapy system 10 ... Treatment planning device 20 ... Radiation therapy device 30 ... Treatment sleeper 40 ... Body surface sensor

Claims (3)

The top plate on which the patient receiving radiation therapy is placed,
A storage unit that stores synchronization information in which the position of the treatment target included in the medical image of the patient and the position of the body surface of the patient are associated with each other.
Based on the synchronization information, the position of the treatment target associated with the position of the body surface of the patient at the time of the radiotherapy is obtained, and the position of the top plate is controlled so that the position of the treatment target is held by the isocenter. Control unit and
A sensor that detects the position of the patient's body surface during radiation therapy ,
Equipped with
The control unit determines the position of the treatment target associated with the position of the patient's body surface detected by the sensor.
Therapeutic sleeper. The top plate on which the patient receiving radiation therapy is placed,
Irradiation means for irradiating the patient and
A storage unit that stores synchronization information in which the position of the treatment target included in the medical image of the patient and the position of the body surface of the patient are associated with each other.
Based on the synchronization information, the position of the treatment target associated with the position of the body surface of the patient at the time of the radiotherapy is obtained, and the position of the top plate is set so that the position of the treatment target is held by the isocenter. The control unit to control and
A sensor that detects the position of the patient's body surface during radiation therapy,
Equipped with
The control unit determines the position of the treatment target associated with the position of the patient's body surface detected by the sensor.
Radiation therapy system. The top plate on which the patient receiving radiation therapy is placed,
Irradiation means for irradiating the patient and
A control unit that controls the position of the top plate so that the position of the treatment target is held by the isocenter regardless of the change in the position of the treatment target in the patient's body due to the patient's breathing.
Equipped with
When the movement of the patient's body surface collected in real time matches the movement of the body surface collected in advance, the control unit starts controlling the position of the top plate and performs radiation therapy to the irradiation means. Notify that can be started,
Radiation therapy system.

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