JP3518270B2 - Charged particle beam equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam device that uses a charged particle beam for cancer treatment and diagnosis of an affected area.

[0002]

2. Description of the Related Art Conventional charged particle beam devices are
-40479. This prior art is shown in FIG.
This will be described using 7.

In FIG. 17, the charged particle beam 82 is z
Go in the direction. When a sinusoidal current with a phase difference of 90 ° is applied to the x-direction scanning electromagnet 80 and the y-direction scanning electromagnet 81, the charged particle beam is circularly scanned by the magnetic field generated in each electromagnet. When a charged particle beam that is circularly scanned is applied to the scatterer 83, the diameter of the charged particle beam is increased, so that the dose distribution in the irradiation region is as shown in FIG. The irradiation dose is uniform in the area over 2r, but 2
Irradiation dose decreases as it goes outside r, resulting in non-uniformity. Therefore, a non-uniform irradiation area is cut by a collimator, and only the irradiation area having a uniform irradiation dose is irradiated to the affected area.

Further, Japanese Patent Laid-Open No. 7-275381 describes that the irradiation range is shaped into an arbitrary shape by controlling the electromagnet in accordance with the shape of the affected area.

[0005]

However, in the prior art, since the non-uniform irradiation area is cut by the collimator, the loss of the charged particle beam is large. Further, in order to obtain a wide irradiation field, the scatterer 83 for increasing the beam diameter must be thickened, which causes a problem of large loss of charged particle beam energy.

An object of the present invention is to provide a charged particle beam device and a method of operating the same, which reduce the loss of the charged particle beam.

[0007]

Means for Solving the Problems The features of the present invention for achieving the above object are an accelerator for emitting an accelerated charged particle beam, and an electromagnet for controlling a plurality of irradiation positions of the charged particle beam in a diseased part to be irradiated. And an irradiation device having a scatterer that expands the charged particle beam that has passed through the electromagnet, and the charged particle beam device is attached to the irradiation device and is positioned at an irradiation position by the charged particle beam expanded by the scatterer. Radiation monitor that measures the irradiation dose, and when the dose measured at the irradiation monitor reaches a target dose, the emission of the charged particle beam from the accelerator is stopped and the emission of the charged particle beam is stopped. In that state, the electromagnet is controlled to change the irradiation position of the charged particle beam to another irradiation position, and after this change, the charged particle beam from the accelerator is changed. In that a control device which initiates the emission.

According to this feature, the irradiation position of the charged particle beam is changed after the emission of the charged particle beam from the accelerator is completed, and the emission of the charged particle beam from the accelerator is started after the irradiation position is changed. The irradiation target is irradiated with the charged particle beam at each irradiation position, and the non-uniform irradiation area around the irradiation target is made smaller than in the case where the charged particle beam is expanded with a scatterer so as to cover the entire irradiation target. Therefore, the loss of the charged particle beam can be reduced. In addition, since the diameter of the charged particle beam expanded by the scatterer is large, when irradiating a plurality of irradiation positions with the charged particle beam, the number of times the irradiation position is changed is small and control is simple.

Further, when the dose for a certain irradiation position measured by the radiation monitor reaches the target dose, the charged particle beam is changed in order to stop the emission of the charged particle beam from the accelerator and change the irradiation position. Even if the intensity of the particle changes with time, the density of the charged particle beam can be uniformly applied to each irradiation position.

Further, preferably, the control device changes the irradiation position of the charged particle beam to an irradiation position determined based on the diameter of the charged particle beam expanded by the scatterer, so that the irradiation by the scatterer is expanded. The irradiation dose of the charged particle beam has a Gaussian distribution in the radial direction centered on the irradiation position, so that the charged particle beams can overlap to form an irradiation area with a uniform irradiation dose, and the charged particle beam can be evenly distributed to the irradiation target. Can be irradiated.

Preferably, the emission switching means is
In the case of a high frequency application device that applies a high frequency electromagnetic field including the frequency of the betatron oscillation of the charged particle beam orbiting the charged particle accelerator to the charged particle beam, the betatron oscillation of the charged particle beam orbiting the charged particle accelerator will resonate. In the state, the applied high frequency electromagnetic field increases the betatron oscillation amplitude of the charged particle beam to exceed the resonance stability limit, and the charged particle beam is emitted from the charged particle accelerator. At this time, since the charged particle beam is emitted constantly, it is possible to irradiate the irradiation target with the charged particle beam with a uniform beam density.

Preferably, the energy changing means changes the energy of the charged particle beam,
The irradiation area of the irradiation target can be changed by changing the energy of the charged particle beam while the irradiation is stopped.

Further, preferably, the charged particle accelerator has an emission switching means for switching emission and stop of the charged particle beam, and the charged particle beam transport system has a transport switching device for switching transport and stop of the charged particle beam. The irradiation device includes a scatterer that expands the charged particle beam,
To provide an electromagnet for setting the irradiation position or irradiation range of the charged particle beam and a control device for changing the irradiation position or irradiation range determined based on the diameter of the charged particle beam in which the irradiation position of the charged particle beam is expanded. is there.

According to this, if the emission switching means emits the charged particle beam circulating in the charged particle accelerator to the irradiation device, and the transportation switching device transports the charged particle beam to the irradiation device, the charged particle beam is irradiated. The irradiation target is irradiated in the device. If the emission switching means stops the emission of the charged particle beam from the charged particle accelerator to the irradiation device, or if the transport switching device stops the charged particle beam,
The irradiation of the irradiation target with the charged particle beam is also stopped. Since the switching of irradiation is performed by two switching means, the safety is higher. Further, the emission switching means or the transport switching device stops the emission of the beam, and the control device changes the next irradiation position or irradiation range based on the diameter of the charged particle beam expanded by the scatterer, and the same at each position. When the dose is irradiated, the irradiation dose of the charged particle beam expanded by the scatterer has a Gaussian distribution in the radial direction centered on the irradiation position, so the charged particle beams may overlap to form an irradiation region with a uniform irradiation dose. Therefore, the irradiation target can be uniformly irradiated with the charged particle beam. Further, since the non-uniform irradiation area around the uniform irradiation area can be reduced, the loss of the charged particle beam can be reduced. Further, since the beam diameter is larger than that in the case where no scatterer is used, the number of times of changing the irradiation position or the irradiation range is small and the control is easy.

[0015] Further, preferably, the control device is provided with a motion detecting means for detecting the motion of the patient, and the control device controls the emission switching means based on the motion of the patient detected by the motion detection. By detecting the movement of the body caused by a cough or the like, the charged particle beam can be irradiated when the affected part is almost stationary, and the irradiation target can be accurately irradiated.

Further, in cancer treatment by a charged particle beam,
It is necessary to change the energy of the charged particle beam to be irradiated depending on the depth of the irradiation target. In this case, preferably, the energy of the charged particle beam that orbits the charged particle accelerator is changed in the accelerating stage, or a substance such as graphite is placed on the plate where the charged particle beam of the irradiation device passes and is emitted. Irradiate by changing the energy of the charged particle beam.

Further, preferably, the scatterer expands the diameter of the charged particle beam, the beam emitting means emits the charged particle beam from the charged particle accelerator, and the electromagnet sets an irradiation position or an irradiation range of the charged particle beam, The control device controls the electromagnet during injection operation, acceleration operation, or deceleration operation of the charged particle accelerator to change the irradiation position or irradiation range.

According to this, after the charged particle beam is emitted by the beam emitting means, the control unit irradiates the charged particle accelerator while the charged particle accelerator is in deceleration operation, beam injection operation or acceleration operation and the beam is not emitted. Since the position or irradiation range is changed to irradiate the charged particle beam irradiation target, the irradiation target is irradiated with the charged particle beam for each irradiation position or irradiation range, and is enlarged by the scatterer so as to cover the entire irradiation target. As compared with the case of expanding the charged particle beam, the non-uniform irradiation area around the irradiation target can be reduced, and the loss of the charged particle beam can be reduced. Further, since the beam diameter is larger than that in the case where no scatterer is used, the number of times of changing the irradiation position or the irradiation range is small and the control is easy.

Preferably, the scatterer expands the diameter of the charged particle beam, the kicker electromagnet moves the charged particle beam from the circular orbit to the exit orbit, and the electromagnet sets the irradiation position or irradiation range of the charged particle beam. The control device controls the electromagnet during the injection operation, acceleration operation, or deceleration operation of the charged particle accelerator based on the expanded diameter of the charged particle beam to change the irradiation position or the irradiation range.

According to this, after the kicker electromagnet moves the charged particle beam from the circular orbit to the emission orbit and emits the beam, the charged particle accelerator is decelerating, injecting or accelerating, and the beam is emitted. While the controller does not operate, the irradiation position or irradiation range is changed based on the expanded diameter of the charged particle beam to irradiate the charged particle beam irradiation target. Compared to the case of expanding the charged particle beam expanded by the scatterer so that the entire area of the irradiation target is irradiated with the beam, the non-uniform irradiation area around the irradiation target can be made smaller, resulting in loss of the charged particle beam. Can be reduced. Further, since the beam diameter is larger than that in the case where no scatterer is used, the number of times of changing the irradiation position or the irradiation range is small and the control is easy. Further, since the irradiation dose of the charged particle beam expanded by the scatterer has a substantially Gaussian distribution in the radial direction around the irradiation position, the charged particle beams can overlap to form an irradiation region with a uniform irradiation dose. The target can be uniformly irradiated with the charged particle beam.

Further, as soon as the kicker electromagnet is excited, the charged particle beam is emitted, and the time for the kicker electromagnet to be excited is such a time that the beam makes one orbit around the orbit. Therefore, charged particles orbiting the accelerator are All are emitted in this time. After that, the irradiation position or the irradiation range is changed while the charged particle accelerator is in the deceleration operation, the beam injection operation, or the acceleration operation.
It is possible to continuously use the beam emitted in a short time such as to make a round.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) A charged particle beam apparatus according to a first embodiment of the present invention will be described with reference to FIG. The charged particle beam system of this embodiment is mainly composed of a pre-stage accelerator 98, a synchrotron type accelerator 100, a rotary irradiation unit 110 and a control unit group 140. Low-energy ions are incident on the accelerator 100 from the pre-stage accelerator 98, accelerated in the accelerator 100, and then emitted to the rotary irradiation device 110 in the treatment room 101,
Ion beams are used for treatment.

The main components of the accelerator 100 will be described. The accelerator 100 applies a high-frequency electromagnetic field to the charged particle beam that orbits the accelerator 100 to increase the betatron oscillation of the charged particle beam, exceed the resonance stability limit, and bring the betatron oscillation of the charged particle beam into a resonance state. It is an accelerator that emits a charged particle beam from the accelerator.

The accelerator 100 applies a magnetic field to the orbiting charged particle beam to deflect the orbiting charged particle beam, a bending electromagnet 146, a high frequency acceleration cavity 147 for giving energy to the orbiting charged particle beam, and a betatron oscillation in a resonance state. The quadrupole electromagnet 145, the multipole electromagnet 11, and the extraction high-frequency applying device 120 for increasing the betatron oscillation by applying a high frequency to the circulating charged particle beam. Further, the deflecting electromagnet 146, the quadrupole electromagnet 145, and the multipolar electromagnet 11 are supplied with current, and the accelerator power supply device 165 for supplying power to the high-frequency acceleration cavity 147 and the extraction high-frequency applying device 120 are supplied with power. A high frequency power source 166 for emission is provided.

The transport system 17 is emitted from the accelerator 100.
The beam transported to the treatment room 101 at 1 is a rotary irradiation device 1
The patient is irradiated at 10.

The rotary irradiation device 110 will be described. The rotary irradiation device 110 includes a quadrupole electromagnet 150 and a deflection electromagnet 151 for transporting an emission beam emitted from the accelerator 100 to an irradiation target, and a power supply device 170 that supplies a current to the quadrupole electromagnet 150 and the deflection electromagnet 151. .

Further, the rotary irradiation device 110 includes an irradiation nozzle 111. The irradiation position of the irradiation nozzle 111 is x
Electromagnets 220 and 221 for moving in the y-direction and the y-direction
Equipped with. Here, the x direction is a direction parallel to the deflection surface of the deflection electromagnet 151, and the y direction is a direction perpendicular to the deflection surface of the deflection electromagnet 151. A power supply device 160 that supplies current is connected to the electromagnets 220 and 221. Electromagnet 220,
A scatterer 300 for increasing the beam diameter is installed downstream of 221. Further, further downstream of the scatterer 300, a dose monitor 301 for measuring the irradiation dose distribution of the beam is provided.
Has been installed. In addition, a collimator 225 is installed immediately in front of the patient to be irradiated so as not to damage the normal tissue around the affected area.

FIG. 2B shows a beam intensity distribution 302 enlarged by the scatterer 300. The beam spread by the scatterer has an almost Gaussian distribution. Therefore, when the beam emission from the accelerator is stopped, as shown in FIG. 2 (b), the beam is expanded by about half the diameter of the beam expanded by the scatterer 300, and when the same dose is applied to each position, they are superposed. As a result, the irradiation dose 303 becomes approximately equal at a position other than the irradiation center position of the beam. Therefore, the dose monitor 301 indicates that the irradiation dose determined in advance in the treatment plan is applied.
After confirming in step 1, the beam from the accelerator is stopped, the irradiation position is moved, and the procedure of emitting the beam from the accelerator is repeated, so that the affected area can be uniformly irradiated.

On the other hand, the non-uniform irradiation dose is 2r.
Outside the area. However, the non-uniform area is small as compared with the case where the irradiation area 2r having a uniform irradiation dose is realized by scanning the charged particle beam in a circular shape. Therefore, the loss of the charged particle beam can be reduced. Further, since the diameter of the beam expanded by the scatterer 300 is smaller than that in the case of scanning the charged particle beam in a circular shape, the thickness of the scatterer 300 can be reduced. Therefore, the energy loss of the charged particle beam can be reduced.

FIG. 3 shows an example of the relationship between the depth inside the body and the irradiation dose of the ion beam. The peak of the irradiation dose in FIG. 3 is called a Bragg peak. The position of the Bragg peak changes depending on the beam energy. Therefore, in the irradiation nozzle 111, as shown in FIG. 4, a range shifter 222 for adjusting the energy and energy width of the beam, a ridge filter 223, and a patient bolus 224 that changes energy according to the shape of the affected area in the depth direction are installed. The ridge filter 223 has a structure in which peaks and valleys are repeated in the x direction of FIG. Particles that pass through the peaks have a large decrease in energy, particles that pass through the valleys have a small decrease in energy, and have an energy distribution according to the height of the peaks and the height of the valleys. Can be made. In this embodiment, a ridge filter in which the energy width of the charged particle beam matches the position where the thickness of the affected part is the largest is used.

The arithmetic device 131 is a device for obtaining data necessary for the control device 132 to control the irradiation of the charged particle beam to the affected area.

The control device 132 emits the charged particle beam from the pre-accelerator 98 to the accelerator 100, accelerates the charged particle beam orbiting the accelerator 100, emits the charged particle beam from the accelerator 100 to the rotary irradiation device 110, and performs rotary irradiation. A device for controlling the transport of a charged particle beam in device 110. Rotation irradiation device 11 from accelerator 100
Since the charged particle beam emitted to 0 irradiates the irradiation target, controlling the emission from the accelerator 100 controls the irradiation of the charged particle beam to the affected area.

First, the role of the arithmetic unit 131 will be described, and then the method of operating the charged particle beam system by the control unit 132 will be described.

The arithmetic unit 131 receives information on the affected part such as the shape and depth of the affected part, the required irradiation dose R and the like and the information such as the thickness and material of the scatterer 300 from the operator. Arithmetic unit 1
31 is based on the input affected part information and scatterer information,
The beam diameter, the irradiation area, the irradiation point in the horizontal direction of the beam, the magnitude of the electric current supplied to the electromagnets 220 and 221, the energy of the charged particle beam irradiated to the affected area, and the required dose are calculated and obtained. It is desirable that the distance between the irradiation points in the horizontal direction be about half the diameter of the beam expanded by the scatterer 300 or less.

The arithmetic unit 131 is shown in FIG. Arithmetic unit 1
The irradiation region forming unit 133 of 31 divides the affected part into a plurality of layers Li (i = 1, 2 ... N) in the depth direction based on the input affected part information, as shown in FIG. The energy calculation unit 134 calculates the beam energy Ei suitable for irradiation according to the depth of each layer.

The irradiation region forming section 133 further includes layers L
A plurality of irradiation areas Ai, j (i = 1, 2 ... N, j = 1,2 ... M) for irradiating the charged particle beam according to the shape of i, a center point Pi, j of the irradiation area Ai, j, And its coordinates (xij, y
ij). Since the intensity of the charged particle beam has a spatially Gaussian distribution, the arithmetic unit 131 determines that the irradiation area Ai, j and the adjacent irradiation area are overlapped with each other based on the diameter of the charged particle beam to obtain a uniform irradiation dose. The center point Pi, j of each irradiation area Ai, j is determined so as to form an area. Each center point Pi, j
Are separated by about half the beam diameter.

The irradiation dose calculation unit 135 obtains the target irradiation dose Rij at each center point Pi, j based on the required irradiation dose R.

The electromagnet current calculation 136 uses the electromagnet 22 to adjust the center point Pi, j to the center of the charged particle beam.
The currents IXij and IYij supplied to 0 and 221 are determined.

The arithmetic unit 131 calculates the beam energy Ei in each layer Li, each irradiation area Ai, j, the center point Pi, j,
Coordinates (xij, yij) of center point Pi, j, target irradiation dose Ri
It outputs j, currents IXij and IYij to the controller 132.

FIG. 7 shows a method of operating the charged particle beam system of this embodiment.

(1) The control device 132 transports the charged particle beam emitted from the accelerator 100 to the rotary irradiation device 110 to the affected area to be irradiated, so that the quadrupole electromagnet 15 is used.
The power supply device 170 is controlled so as to supply a current to the zero and the deflection electromagnet 151.

(2) The controller 132 uses the pre-stage accelerator 98.
Controls the pre-accelerator 98 so that the beam emits a charged particle beam.

(3) The control device 132 supplies current to the deflection electromagnets 146 and quadrupole electromagnets 145 in order to accelerate the orbiting charged particle beam to the energy Ei, and powers the high frequency acceleration cavity 147. The accelerator power supply device 165 is controlled so that the power is supplied.

(4) When the orbiting charged particle beam is accelerated to the energy Ei, the controller 132 causes the quadrupole electromagnet 145 and the multipole electromagnet to bring the betatron oscillation of the orbiting charged particle beam into resonance. The power supply device for accelerator 165 is controlled so as to supply a current to the power supply 11.

4-pole electromagnet 145 and multi-pole electromagnet 11
When a current is supplied to the beam, a stability limit of resonance for emission occurs, and the orbital charged particle beam moved outside the stability limit has a betatron oscillation in a resonance state.

(5) The control device 132 controls the electromagnet 22 to match the center of the charged particle beam with the center point Pi, j.
The power supply device 160 is controlled so as to supply the currents IXij and IYij to 0 and 221.

(6) The controller 132 controls the target irradiation dose R
ij is compared with the irradiation dose of the center point Pi, j measured by the dose monitor 301.

(7) When the irradiation dose at the center point Pi, j does not reach the target irradiation dose Rij, the control device 132 applies the extraction high frequency to start the extraction from the accelerator 100 to the rotary irradiation device 110. The extraction high frequency power supply 166 is controlled so as to supply power to the device 120.

When power is supplied to the extraction high-frequency applying device 120, a high-frequency electromagnetic field is applied to the orbiting charged particle beam, and the betatron oscillation amplitude of the orbiting charged particle beam increases. When the betatron oscillation amplitude increases and exceeds the resonance stability limit of the betatron oscillation, the charged particle beam is emitted from the accelerator 100 to the rotary irradiation device 110. In the rotating irradiation device 110, the irradiation area Ai, j is irradiated with the charged particle beam.

(8) The controller 132 controls the target irradiation dose R
ij is compared with the irradiation dose of the center point Pi, j measured by the dose monitor 301. When the irradiation dose at the central point Pi, j does not reach the target irradiation dose Rij, the extraction is continued.

(9) The controller 132 controls the extraction high-frequency power source 166 so that the extraction is stopped when the irradiation dose at the central point Pi, j reaches the target irradiation dose Rij. Then, the power supply device 160 is controlled so that the center of the charged particle beam is aligned with the center point Pi, j + 1 of the next irradiation area Ai, j + 1.

(10) When the beam circling the accelerator 100 can be used when the irradiation of the irradiation area Ai, j is changed to the irradiation of the irradiation area Ai, j + 1, the operation from (5) is performed. If the beam amount and the extraction time are insufficient, the operation from (2) is performed to replenish the charged particle beam.

(11) All irradiation areas Ai, j of the layer Li
Then, when the irradiation dose reaches the target value, the operation from (1) is performed for the next layer Li + 1, and all the irradiation regions Ai + 1, j are irradiated as in the case of the layer Li. All layers of the affected area Li
After irradiating, the operation of the charged particle beam system is terminated.

According to the embodiment, the affected layer LI can be irradiated with a uniform irradiation dose. Since the non-uniform irradiation region formed outside the boundary of the layer LI of the affected area is cut out by the collimator 225, it is possible to perform irradiation with the charged particle beam that matches the shape of the affected area. In addition, since the region to be cut out is smaller than that in the case of scanning the charged particle beam in the conventional circular shape, the treatment irradiation can be performed with a small beam loss. Further, although the irradiation position of the charged particle beam is set by two electromagnets, the patient bed 112 is structured to be movable, and the control device 132 is used.
The irradiation position may be set by controlling from.

If the scatterer 300 is not used, the diameter of the charged particle beam to be irradiated is small. Therefore, it is necessary to make the irradiation position interval extremely small in order to obtain a uniform irradiation intensity distribution. Control becomes extremely complicated. In the present embodiment, by using the scatterer 300, the charged particle beam has a substantially Gaussian distribution and the beam diameter can be increased to an appropriate size. Therefore, the irradiation position interval is not extremely small, and the irradiation dose is uniform. Distribution can be realized.

As described above, the charged particle beam system of this embodiment can reduce the loss of the charged particle beam and form a uniform irradiation field.

Further, according to the present embodiment, even when the irradiation target has a complicated shape, the affected area can be irradiated with high accuracy. Further, since the irradiation is continued until the irradiation dose reaches the target, even if the beam intensity changes with time, the affected area can be uniformly irradiated with the beam density.

In this embodiment, the synchrotron is used as the accelerator, but the cyclotron 172 may be used as the accelerator as shown in FIG. Cyclotron 17
The emission and the stop of the beam from No. 2 are performed by controlling the deflector power supply 174 for the deflector 175 by a signal from the control device 132 and supplying and stopping the charged particle beam from the ion source 173.

(Embodiment 2) Next, a second embodiment of the present invention will be described. The device configuration of this embodiment is similar to that of the first embodiment. However, in this embodiment, the irradiation region of each layer Li of the affected area is not divided in the x direction, but is divided only in the y direction as shown in FIG. That is, the irradiation area Ai, j is wide in the x direction. When irradiating the irradiation area Ai, j, the intensity of the magnetic field generated by the electromagnet 220 is changed, and the charged particle beam is scanned and irradiated in the x direction.

Based on the diameter of the charged particle beam, the arithmetic unit 131 overlaps the irradiation area Ai, j with the adjacent irradiation area to form a uniform irradiation dose area for each irradiation area Ai.
The center point Pi, j of i, j is determined. The center points Pi, j should be separated by about half the beam diameter.

Then, the arithmetic unit 131 determines that each irradiation area A
The magnitude ΔIXij for changing the magnetic field strength of the electromagnet 220 is obtained based on the spread of i, j in the x direction. Then, as in the case of the first embodiment, the beam energy Ei of each layer Li, each irradiation area Ai, j and its center point Pi, j (xij,
yij), target irradiation dose Rij, currents IXij and IYij, and these and ΔIXij are output to the controller 132.

A method of operating the charged particle beam system of this embodiment is shown in FIG. Except for (7), it is the same as the first embodiment.

At (7), the controller 132 controls the accelerator 10
In order to start emission from the rotary irradiation device 110 from 0, the extraction high frequency power source 166 is controlled so as to supply power to the extraction high frequency application device 120, and the charged particle beam is scanned and irradiated in the x direction. Therefore, the power supply device 160 is controlled so that the current IXij of the electromagnet 220 changes within the range of ΔIXij.

In this embodiment, when the irradiation area Ai, j is irradiated, the intensity of the magnetic field generated by the electromagnet 220 is changed to scan the charged particle beam in the x direction for irradiation, but the magnetic field generated by the electromagnet 221 is used. Of the charged particle beam may be scanned in the y direction to irradiate the charged particle beam.

According to this embodiment, the same effect as that of the first embodiment can be obtained, and the switching between the emission and the stop of the charged particle beam is performed only in the y direction (or the x direction). The irradiation time can be shortened as compared with the embodiment.

(Third Embodiment) Next, a third embodiment of the present invention will be described. In this embodiment, a charged particle beam device having the same configuration as in FIG. 1 is used,
The configuration of the irradiation nozzle 111 and its control device 132 are different. FIG. 11 shows the irradiation nozzle 111 of this embodiment.

In this embodiment, the scatterer 300 is made thinner than in the first embodiment. Since the diameter of the charged particle beam expanded by the scatterer 300 is smaller than that in the first embodiment, the number of irradiation areas Ai, j increases. On the other hand, since the spread of the beam diameter is small, the patient collimator used in the first embodiment is not used. Similarly, since the beam diameter is smaller than that of the first embodiment, the ridge filter and the bolus used in the first embodiment are not used.

Further, in the first embodiment, the energy of the charged particle beam in the accelerator 100 is set to Ei, but in the present embodiment, the thickness of the range shifter 222 is stopped while the controller 132 is stopping the beam emission from the accelerator 100. The energy of the charged particle beam by changing the
i.

FIG. 12 shows the method of operating the charged particle beam system of this embodiment. Except for (3) and (4), it is the same as the first embodiment.

(3) The control unit 132 accelerates the charged particle beam that orbits to the rated energy E larger than the beam energy Ei of each layer in order to accelerate the deflection electromagnet 14.
The power supply device for accelerator 165 is controlled so as to supply a current to the 6, 4-pole electromagnet 145 and supply power to the high-frequency acceleration cavity 147. Then, in order to reduce the rated energy E to the energy Ei of the beam,
The thickness of the range shifter 222 is adjusted.

(4) When the orbiting charged particle beam is accelerated to the energy E, the control device 132 sets the quadrupole electromagnet 145 and the multipole electromagnet to bring the betatron oscillation of the orbiting charged particle beam into resonance. The power supply device for accelerator 165 is controlled so as to supply a current to the power supply 11.

As described above, the charged particle beam system of this embodiment can reduce the loss of the charged particle beam and form a uniform irradiation field. Further, the affected area can be accurately irradiated without using a collimator or bolus for each patient.

In the present embodiment, the electromagnet 2 for setting the irradiation position is set in a state where the thickness of the range shifter is constant and the irradiation depth is constant.
The irradiation is performed by repeatedly changing the intensities of 20, 221 to irradiate a layer having a certain depth, and then the same procedure is repeated by changing the thickness of the range shifter. After the layers are divided and the intensity of the electromagnets 220 and 221 is kept constant, the irradiation is stopped and then the range shifter thickness is changed to perform the irradiation procedure. Similar irradiation treatment can be performed by changing the intensity.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described. The device configuration of this embodiment is shown in FIG. The device configuration differs from that of the first embodiment in that a motion detector 250 for detecting the motion of the body of the patient is provided, and a beam transport system 171 for transporting the charged particle beam to the irradiation device has a charged particle beam. Since the switching electromagnet 177 and the power supply 176 for switching between the transportation and the stop are provided, the other configuration is the same as that of the first embodiment. However, the power source 176 is arranged so that the patient is not irradiated with the beam when a failure occurs and current does not flow, and is irradiated only when the current is normally applied.

The motion detector 250 may be a strain detecting device installed on the body surface, or may be a device for detecting the patient's motion with a camera. The signal from the motion detector 250 detects the movement of the patient's body, and outputs a signal for emitting a beam to the patient only when the movement of the body is small. Send to 176. Only when the signal is beam irradiation possible, a high frequency power is applied to the charged particle beam from the extraction high frequency power source 166, and a current is applied from the power source 176 to the beam transfer system switching electromagnet 177 to rotate the charged particle beam 110. To be supplied to. The operating method at this time is shown in FIG. Except for the operating methods (7) and (9), the operation is the same as in the first embodiment.

In (7), when the irradiation dose at the center point Pi, j does not reach the target irradiation dose Rij and the signal from the motion detector 250 determines that the patient is stationary, the control is performed. The device 132 includes the accelerator 100 to the rotary irradiation device 110.
In order to start emission to the
The high frequency power source for extraction 166 is controlled so as to supply electric power to the power source, and at the same time, a current is applied from the power source 176 to the switching electromagnet 177 of the charged particle beam transport system. However, when the signal from the motion detector 250 determines that the patient is not stationary, the power of the extraction high frequency power source 166 and the charged particle beam transport system switching electromagnet 177 is controlled to control the charged particle beam. The supply to the rotary irradiation device 110 is stopped.

In (9), the control unit 132 determines that the center point P
When the irradiation dose of i, j reaches the target irradiation dose Rij, the high-frequency power source 166 for extraction is controlled so as to stop the extraction, and the current of the switching electromagnet 177 of the beam transport system is stopped to charge the charged particle beam. Supply to the rotary irradiation device 110 is stopped. Then, the power supply device 160 is controlled so that the center of the charged particle beam is aligned with the center point Pi, j + 1 of the next irradiation area Ai, j + 1.

According to this embodiment, the same effect as that of the first embodiment can be obtained, and the irradiation can be switched by two switching means, so that the safety is higher. Further, since the charged particle beam is irradiated when the affected part is almost stationary, the irradiation target can be accurately irradiated.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. The device configuration of this embodiment is shown in FIG. The device configuration is different from that of the first embodiment in that the kicker electromagnet 12 is used for beam emission from the accelerator.
The point is to use 1. Region division of the affected area is performed as shown in FIG. 6 as in the first embodiment.

The kicker electromagnet 121 is pulse-excited from the power source 167 of the kicker electromagnet. When a pulse current is supplied from the power supply 167 to the kicker electromagnet 121 by the signal from the control device 132, the kicker electromagnet 121 is excited for a time such that the beam makes one round orbit, and gives a magnetic field to the orbiting charged particle beam. . The orbiting charged particle beam is separated from the orbit and immediately emitted to the transport system 171 when a magnetic field is applied from the kicker electromagnet 121.
Since a magnetic field is applied to the beam for a time such that the beam makes one round orbit, the charged particles that orbit the accelerator are all emitted during this time. Therefore, set the kicker electromagnet 121 to 1
When the pulse excitation is performed twice, the beam emission ends. The present embodiment is suitable for continuously using a beam emitted in a short time such that the beam makes one round orbit.

FIG. 16 shows the operation method in this embodiment.
In (1), the excitation amount of the electromagnet of the rotary irradiation device 110 is set by the signal from the control device 132 so that the charged particle beam of energy Ei can be transported. Then, in (2) to (5), the pre-stage accelerator 98 is set. Beam injection to the accelerator 100, acceleration of the orbiting charged particle beam, and excitation by the kicker electromagnet 121 and emission thereof are repeated. When it is determined in (6) that the predetermined dose has not been reached for each partial area Ai, j, the beam incidence, acceleration, and emission are further repeated. Then, after irradiating the partial area Ai, j with a predetermined dose in (6), the beam irradiation position setting electromagnets 220, 2 are responsive to a signal from the controller 132 in (4).
The currents IXij and IYij of 21 are changed to change the irradiation position. Then, when it is determined in (7) that the irradiation of the layer Li is completed, the irradiation, acceleration, and emission of the beam are repeated until the irradiation layer is changed in (8) and all layers are completed.

[0082]

According to the present invention, the irradiation target is irradiated with the charged particle beam at each irradiation position. Therefore, compared with the case where the charged particle beam is expanded by a scatterer so as to cover the entire irradiation target, The non-uniform irradiation area around the irradiation target can be reduced, and the loss of the charged particle beam can be reduced. In addition, since the diameter of the charged particle beam expanded by the scatterer is large, when irradiating a plurality of irradiation positions with the charged particle beam, the number of times the irradiation position is changed is small and control is simple. Furthermore, when the dose for a certain irradiation position measured by the radiation monitor reaches the target dose, the emission of the charged particle beam from the accelerator is stopped and the irradiation position is changed. Even if it changes with time, the density of the charged particle beam can be uniformly applied to each irradiation position.

[Brief description of drawings]

FIG. 1 is a diagram showing a charged particle beam system according to a first embodiment.

FIG. 2 is a diagram showing a beam intensity distribution 302 enlarged by a scatterer.

FIG. 3 is a diagram showing an example of the relationship between the depth inside the body and the irradiation dose of an ion beam.

FIG. 4 is a diagram showing an irradiation nozzle 111 according to the first embodiment.

FIG. 5 is a diagram showing an arithmetic unit 131.

FIG. 6 is a diagram showing area division of an affected area according to the first embodiment.

FIG. 7 is a diagram showing a flowchart showing a procedure of operation of the first embodiment.

FIG. 8 is a diagram showing a charged particle beam device using a cyclotron 172.

FIG. 9 is a diagram showing area division of an affected area according to a second embodiment.

FIG. 10 is a view showing a flowchart showing a procedure of operation of the second embodiment.

FIG. 11 is a diagram showing an irradiation nozzle 111 according to a third embodiment.

FIG. 12 is a view showing a flowchart showing a procedure of operation of the third embodiment.

FIG. 13 is a diagram showing a charged particle beam system according to a fourth example.

FIG. 14 is a diagram showing a method of operating the charged particle beam system according to the fourth embodiment.

FIG. 15 is a diagram showing a charged particle beam system according to a fifth example.

FIG. 16 is a view showing a flowchart showing a procedure of operation of the fifth embodiment.

FIG. 17 is a schematic configuration diagram of a conventional charged particle beam device.

[Explanation of symbols]

11 ... Multi-pole electromagnet, 80 ... x-direction scanning electromagnet, 81 ... y
Directional scanning electromagnet, 82 ... Charged particle beam, 83, 300
... Scatterer, 98 ... Pre-accelerator, 100 ... Accelerator, 101
... treatment room, 110 ... rotational irradiation device, 111 ... irradiation nozzle, 112 ... patient bed, 120 ... radiation high-frequency applying device, 121 ... kicker electromagnet, 131 ... arithmetic device, 13
2 ... Control device, 145, 150 ... Quadrupole electromagnet, 146,
151 ... Bending electromagnet, 147 ... High-frequency acceleration cavity, 16
0,170 ... Power supply device, 165 ... Accelerator power supply device, 1
67, 176 ... Power source, 166 ... High frequency power source for emission, 17
1 ... Beam transport system, 172 ... Cyclotron, 173 ...
Ion source, 174 ... Deflector power supply, 175 ... Deflector, 17
8 ... switching electromagnets, 220, 221 ... electromagnets, 222
... range shifter, 223 ... ridge filter, 224 ... patient bolus, 225 ... collimator, 250 ... motion detector, 301 ... dose monitor, 302 ... expanded beam intensity distribution, 303 ... irradiation dose.

─────────────────────────────────────────────────── ───Continued from the front page (56) Reference JP-A-7-303710 (JP, A) JP-A-7-142351 (JP, A) JP-A-7-275381 (JP, A) JP-A-1- 320073 (JP, A) JP-A-48-75291 (JP, A) JP-A-5-40479 (JP, Y2) International publication 95/33519 (WO, A1) (58) Fields investigated (Int.Cl. ⁷⁾ , DB name) A61N 5/10 G21K 5/04

Claims (8)

(57) [Claims] 1. An accelerator for emitting an accelerated charged particle beam, an electromagnet for controlling a plurality of irradiation positions of the charged particle beam on an affected area to be irradiated, and a scattering for expanding the charged particle beam passing through the electromagnet. A charged particle beam device comprising an irradiation device having a body, the radiation monitor being attached to the irradiation device for measuring a dose irradiated to the irradiation position by the charged particle beam expanded by the scatterer, When the dose to the irradiation position measured by the radiation monitor reaches a target dose, the emission of the charged particle beam from the accelerator is stopped, and the electromagnet is stopped in the state of stopping the emission of the charged particle beam. To change the irradiation position of the charged particle beam to another irradiation position, and after this change, the charged particle beam from the accelerator is changed. A charged particle beam apparatus characterized by comprising a control device for starting the emission of the beam. 2. An accelerator having a high-frequency applying device for emitting a charged particle beam by applying a high-frequency electromagnetic field, an electromagnet for controlling a plurality of irradiation positions of the charged particle beam in an affected area to be irradiated, and the electromagnet. A charged particle beam device comprising: an irradiation device having a scatterer that expands the passed charged particle beam, wherein the charged particle beam is attached to the irradiation device and is expanded to the irradiation position by the charged particle beam expanded by the scatterer. A radiation monitor for measuring the dose to be irradiated, and when the dose to the certain irradiation position measured by the radiation monitor reaches the target dose, the application of the high-frequency electromagnetic field by the high-frequency applying device is stopped and the accelerator is used. Of the charged particle beam is stopped, and the electromagnet is controlled in a state where the charged particle beam is stopped. A control device for changing the irradiation position of the charged particle beam to another irradiation position, and after this change, starts the application of the high frequency electromagnetic field by the high frequency applying device to start the emission of the charged particle beam from the accelerator. A charged particle beam device comprising: 3. An accelerator having a kicker electromagnet that emits a charged particle beam, an electromagnet that controls a plurality of irradiation positions of the charged particle beam in an affected area that is an irradiation target, and the charged particle beam that has passed through the electromagnet is expanded. A charged particle beam device including an irradiation device having a scatterer, the radiation monitor being attached to the irradiation device, for measuring a dose irradiated to the irradiation position by the charged particle beam expanded by the scatterer. And, when the dose to the certain irradiation position measured by the radiation monitor reaches the target dose, the emission of the charged particle beam from the accelerator is stopped, and the emission of the charged particle beam is stopped. The irradiation position of the charged particle beam is changed to another irradiation position by controlling the electromagnet, and after the change, the irradiation position of the accelerator is changed. A charged particle beam apparatus characterized by comprising a control device for starting the extraction of the charged particle beam. 4. The control device changes the irradiation position of the charged particle beam to the irradiation position determined based on the diameter of the expanded charged particle beam. The charged particle beam device according to any one of 1. 5. The charged particle beam apparatus according to claim 1, further comprising energy changing means for changing the energy of the charged particle beam. 6. The charged particle beam device according to claim 5, wherein the energy changing means is provided in the irradiation device. 7. The control device, when the irradiation position of the charged particle beam is moved from one of the plurality of layers in the affected area divided in the depth direction to the other layer 7. The charged particle beam device according to claim 6, wherein the energy changing means provided in the irradiation device is controlled to change the energy of the charged particle beam. 8. The control device, when the irradiation position of the charged particle beam is moved from one of the plurality of layers in the affected area divided in the depth direction to the other layer. 3. A power supply device for an accelerator that supplies a current to a quadrupole electromagnet and a deflection electromagnet provided in the accelerator in order to change the energy of the charged particle beam.
Alternatively, the charged particle beam device according to claim 3.