JP2001212253A - Particle ray irradiation method and particle ray irradiation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to uniformly, accurately and easily irradiate over a three dimensional irradiation area. SOLUTION: The particle ray irradiation equipment is provided with a range shifter 7 to shift the energy of particle ray spot beam to plural kinds and scanning magnets 3a, 3b to shift the position to be irradiated by the particle ray. The energy and the position of particle ray spot beam are controlled during the irradiation on the affected part. A scatterer device 9 is provided, which can shift the diameter of spot beam to plural kinds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for irradiating a particle beam emitted from a particle accelerator, and more particularly to a three-dimensional particle irradiation apparatus and a three-dimensional irradiation method used for a particle beam therapy system.

[0002]

2. Description of the Related Art In recent years, particle beam therapy using protons and heavy particles has attracted attention as a method for treating cancer, which accounts for about one third of the causes of death in Japan. In this method, by irradiating a cancer cell with a proton beam or a heavy particle beam emitted from the accelerator, only the cancer cells can be killed without substantially affecting normal cells.

[0003] Particle beam therapy irradiation methods mainly used at present are referred to as a Wobble method or a double scatterer method.
As a three-dimensional irradiation method, as a more advanced treatment method of particle beam therapy, a method of aiming cancer cells with higher accuracy by scanning the irradiation position of a spot beam three-dimensionally has been proposed. Department has been put to practical use.

A typical one of the three-dimensional irradiation methods is as follows.
This is called a three-dimensional spot scanning method or a three-dimensional raster method. Generally, the spot scanning method clearly divides the irradiation spot and scans the irradiation position while the irradiation is stopped, and the raster method has a difference that the division of the irradiation spot is not clear.

[0005] According to these three-dimensional irradiation methods, the irradiation area can be accurately adjusted to the affected part, and the exposure to the normal affected part can be suppressed as compared with the conventional two-dimensional irradiation method.

Hereinafter, a three-dimensional irradiation apparatus for performing a cancer treatment by a three-dimensional spot scanning method will be described with reference to the drawings.

FIG. 11 is a schematic configuration diagram of a three-dimensional irradiation apparatus for three-dimensional spot scanning arranged in a treatment room. In FIG. 11, 1 is a treatment bed, and 2 is a three-dimensional irradiation device. The three-dimensional irradiation device 2 includes scanning magnets 3a and 3b, a dose monitor 4, a position monitor 5, a ridge filter 6, a range shifter 7, and a control computer 8.

Next, the configuration and function of each device of the three-dimensional irradiation apparatus shown in FIG. 11 will be described.

The scanning magnets 3a and 3b scan the spot beam incident on the scanning magnet at a point (X, Y) on a plane perpendicular to the beam axis in the affected part of the body.

The range shifter 7 controls the position (Z) in the direction of the beam axis in the affected part of the body. This range shifter 7
It is composed of a plurality of acrylic plates having different thicknesses, and by appropriately combining these acrylic plates, the beam energy passing through the range shifter, that is, the in-vivo range can be changed stepwise. The control of the in-vivo range in the range shifter 7 is generally switched at a fixed interval.

Since the dose distribution of the monoenergetic particle beam in the body depth direction has a very sharp peak (hereinafter referred to as Bragg peak) distribution in the vicinity of the body range, it is switched by the range shifter using the ridge filter 6. The in-vivo range of the monoenergetic particle beam is expanded so as to correspond to the interval distance of the in-vivo range.

The dose monitor 4 is for measuring the dose to be radiated into the body, and the position monitor 5 is for discriminating whether or not the beam position scanned by the scanning magnets 3a and 3b is at a correct position. Things.

The control computer 8 controls the settings of these devices.

Using these irradiation devices, three-dimensional irradiation is performed by the following method.

In the irradiation pattern table held in the control computer 8, spot positions (Xi, Yi, Z) and irradiation doses (Di) are written. Spot irradiation is performed based on this irradiation pattern table.

The incident energy of the particle beam and the thickness of the acrylic plate in the range shifter 7 are selected according to the position (Zi) of the deepest slice.

Next, with respect to the deepest slice, the position (X
i, Yi) [i = 1 to n] is selected and the scanning magnet 3
These positions (Xi, Yi) are irradiated by a and 3b. The particle beam having a single energy in the scanning magnets 3 a and 3 b is converted by the ridge filter 6.
The energy distribution is expanded so that the in-vivo range distribution corresponds to the slice width. The position on this slice (Xi,
The irradiation dose of Yi) is monitored by the dose monitor 4, and when the irradiation of the scheduled dose (Di) is detected, the beam is stopped, and the scanning magnets 3a and 3b irradiate the next position (Xi + 1, Yi) on the same slice. +1).

When the irradiation of all the points in this slice is completed, the acrylic thickness in the range shifter 7 is changed,
The irradiation of the next slice (Zi + 1) is performed. By repeating this sequentially for each slice, irradiation is performed three-dimensionally.

As described above, in three-dimensional irradiation, the irradiation pattern is determined according to the shape of the affected part and the irradiation direction. The formation of the irradiation pattern is called a treatment plan, and is performed using a treatment planning software by identifying an affected part by a method such as X-ray CT imaging. According to this treatment plan, the three-dimensional irradiation position (Xi, Yi, Z
i) and the irradiation dose (Di) are tabulated in advance and taken into the control computer 8.

In the control computer 8, of the three-dimensional irradiation positions, the position (Xi, Yi) in the direction perpendicular to the beam axis is converted into the current value of the magnet, and the position Zi in the beam axis, that is, the internal range is converted into the thickness of the range shifter. Controls each irradiation device.

By irradiating the affected part in the body three-dimensionally as described above, it is possible to perform irradiation in accordance with the shape and size of the affected part more accurately than in the conventional two-dimensional irradiation method. Becomes possible.

However, the three-dimensional irradiation method such as the three-dimensional spot scanning method has the following problems. Since the irradiation beam is scattered by the range shifter for controlling the position Zi in the beam axis direction, the beam diameter at the spot position in the affected part changes depending on the thickness of the range shifter. For example, when irradiating deep into the affected area,
The use of a thin range shifter causes less influence of scattering and a small beam diameter spread, but when irradiating a shallow part of an affected part, the beam diameter spreads large because a thick range shifter is used.

However, current treatment planning software is:
For the sake of simplicity, the beam diameter is made the same so as to create an irradiation pattern. Therefore, there is a problem that if the irradiation is performed in accordance with the irradiation pattern formed by the treatment plan, it is not possible to perform the irradiation with uniformity as planned. Also, it is very difficult to produce treatment planning software that captures changes in the beam diameter due to the complexity of the algorithm.

On the other hand, in order to form a three-dimensionally uniform irradiation dose distribution as described above, it is desirable that the beam diameter at each spot is the same, but the spots on the plane perpendicular to the beam axis are If the beam diameter is smaller than the interval, the irradiation dose distribution in this plane will have irregularities, and will no longer be uniform.

In order to avoid this unevenness, a spot beam having a certain beam diameter is applied according to the spot interval as shown in FIG. However, when a spot beam with a large beam diameter is irradiated, the dose distribution at the boundary of the irradiation area becomes poor, and the tissue in the area that does not originally need to be irradiated is exposed, and normal tissues are damaged.

[0026]

As described above, in the conventional three-dimensional irradiation method, the beam diameter at the spot position in the affected area changes depending on the thickness of the range shifter due to the scattering by the range shifter. There is a problem that uniform irradiation as described above cannot be performed.

Furthermore, since a spot beam having a large beam diameter is irradiated, the dose distribution at the boundary of the irradiation region becomes poor, and the tissue in the region that does not need to be irradiated is exposed to radiation, and normal tissue is damaged. There was a problem.

The present invention has been made in order to solve the above-mentioned problems, and the beam diameter can be adjusted for each spot position in an affected part, the beam diameter can be uniformed over an irradiation area, and
It is an object of the present invention to provide a three-dimensional irradiation method and an irradiation device capable of favorably cutting a dose at an irradiation region boundary.

[0029]

In order to achieve the above object, the present invention comprises a particle beam irradiation method and a particle beam irradiation apparatus by the following means.

According to a first aspect of the present invention, there is provided a particle beam irradiation method for controlling the energy and the position of a particle beam spot beam to irradiate a portion to be irradiated. Irradiation is performed by controlling the beam diameter.

According to a second aspect of the present invention, there is provided a particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated. Irradiation is performed by controlling the beam diameter by a beam diameter adjusting means capable of switching a plurality of beam diameters.

According to a third aspect of the present invention, there is provided a particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to match the shape and size of a portion to be irradiated. Irradiation is performed under the control of the beam diameter adjusting means capable of switching the spot beam diameter to a plurality, using the energy or the position in the beam axis direction among the three-dimensional irradiation positions or the state of the energy switching mechanism as one of the parameters.

According to a fourth aspect of the present invention, there is provided a particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated. The area is divided into a plurality of groups, and irradiation is performed by controlling the beam diameter corresponding to each group by a beam diameter adjusting means capable of switching the spot beam diameter to a plurality.

According to a fifth aspect of the present invention, in the particle beam irradiation method according to the fourth aspect of the present invention, a spot position near an irradiation area boundary is set as one of the groups, and Irradiation is performed by controlling the diameter of the spot beam for irradiating the spot so as to be smaller than the spot at the central position of the irradiation area.

According to a sixth aspect of the present invention, there is provided a particle beam irradiation method for sequentially controlling the energy and the position of a particle beam spot beam to perform three-dimensional irradiation so as to match the shape and size of a portion to be irradiated. The area is divided into a plurality of groups, and irradiation is performed sequentially from the spots in the same group.

According to a seventh aspect of the present invention, there is provided a particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated. The area is divided into a plurality of groups, and the beam diameter is controlled by a beam diameter adjusting means capable of switching the spot beam diameter to a plurality of groups for each group, and irradiation is sequentially performed from spots in the same group.

According to an eighth aspect of the present invention, in the particle beam irradiation method according to any one of the first to fourth and seventh aspects, the beam diameter adjusting means is configured to emit one or more scatterers. The beam diameter is controlled by moving the beam in and out of the axis.

According to a ninth aspect of the present invention, in the particle beam irradiation method according to any one of the first to fourth and seventh aspects, the beam diameter adjusting means controls the beam diameter with a focusing electromagnet. .

According to a tenth aspect of the present invention, there is provided a mechanism for switching the energy of the particle beam spot beam to a plurality, and a mechanism for switching the irradiation position of the particle beam to control the energy and position of the particle beam spot beam. In the particle beam irradiation apparatus for irradiating the irradiation target part with a beam diameter, a beam diameter adjusting mechanism capable of switching a plurality of spot beam diameters is provided.

According to an eleventh aspect of the present invention, there is provided a mechanism for switching the energy of a particle beam spot beam to a plurality, a mechanism for switching an irradiation position of the particle beam, and a method for irradiating the energy of the particle beam spot beam and the irradiation position. In a three-dimensional particle beam irradiation apparatus including a control computer that sequentially controls the shape and size of a part so as to match the shape and size of the part, a beam diameter adjustment mechanism capable of switching a spot beam diameter to a plurality,
A mechanism is provided for controlling the beam diameter adjusting mechanism using the three-dimensional irradiation position or the value of the energy or the state of the energy switching mechanism as one of the parameters.

According to a twelfth aspect of the present invention, there is provided a mechanism for switching the energy of a particle beam spot beam to a plurality, a mechanism for switching an irradiation position of the particle beam, and a method for irradiating the energy of the particle beam spot beam and the irradiation position. In a three-dimensional particle beam irradiation apparatus provided with a control computer for sequentially controlling so as to match the shape and size of a part, a beam diameter adjusting mechanism capable of switching a plurality of spot beam diameters,
The energy switching mechanism, the irradiation position switching mechanism, and the control mechanism for controlling the spot beam diameter adjusting mechanism are provided using the two-dimensional irradiation position and the spot beam diameter as parameters.

An invention corresponding to claim 13 is claim 10.
In the particle beam irradiation apparatus according to any one of the above aspects, the beam diameter adjusting mechanism is constituted by a plurality of scatterer devices.

The invention corresponding to claim 14 is the invention according to claim 10
In the particle beam irradiation apparatus according to any one of to 12,
The beam diameter adjusting mechanism includes a focusing electromagnet.

The invention corresponding to claim 15 is the invention according to claim 10.
In the particle beam irradiation apparatus according to any one of the above aspects, a range shifter is used as a mechanism for switching the energy of the particle beam spot beam.

The invention corresponding to claim 16 is based on claim 15.
In the particle beam irradiation apparatus according to the invention, the range shifter is formed of one or more plates, and the plate has a thickness different from that of the plate having a thickness corresponding to the material or the thickness of the plate. The one with the membrane attached.

Therefore, according to the invention as described above, the beam diameter adjusting mechanism eliminates the influence of the particle beam scattering in the range shifter and the body, and can easily obtain the same beam diameter regardless of the three-dimensional irradiation position. It is possible to obtain.

Here, the control of the beam diameter adjusting mechanism is carried out by calculating using the range shifter thickness, the irradiation position in the beam axis direction which gives the range shifter thickness or the energy value as a parameter.

Therefore, uniform and accurate irradiation over the three-dimensional irradiation area can be easily performed.

Also, the parameters of the three-dimensional irradiation table include the spot diameter in addition to the irradiation dose and the three-dimensional irradiation position, and the irradiation can be performed with the spot diameter changed for each irradiation spot. For this reason, for example, the beam diameter at the spot position near the boundary can be made smaller than the spot position at the center.

Therefore, the irradiation dose can be uniform over the irradiation region and the irradiation dose can be sharply cut off at the boundary of the irradiation region, and the exposure to normal tissues can be reduced.

[0051]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a three-dimensional irradiation apparatus for a three-dimensional spot scanning method in which a gore is disposed in a treatment room according to a first embodiment of the present invention. The same parts will be described with the same reference numerals.

In FIG. 1, reference numeral 1 denotes a treatment bed,
0 is a three-dimensional irradiation device. The three-dimensional irradiation device 10 includes scanning magnets 3a and 3b, a dose monitor 4, a position monitor 5, a ridge filter 6, a range shifter 7, and a control computer 8.
And a scatterer device 9.

Next, the configuration and function of each device of the three-dimensional irradiation apparatus shown in FIG. 1 will be described.

The scanning magnets 3a and 3b scan the spot beam incident on the scanning magnet at a point (X, Y) on a plane perpendicular to the beam axis in the affected part of the body.
Here, the scanning magnets 3a and 3b are an X-direction scanning magnet that scans the beam in the X direction and a Y-direction scanning magnet that scans the beam in the Y direction, respectively.

The range shifter 7 controls the position (Z) in the beam axis direction in the affected part of the body. The range shifter 7 is composed of a plurality of acrylic plates having different thicknesses, and changes the beam energy passing through the range shifter, that is, the in-vivo range in a stepwise manner by a combination of these acrylic plates.

The ridge filter 6 includes a range shifter 7
The internal range of the monoenergetic particle beam is expanded so as to correspond to the interval of the internal range switched by the above.

The scatterer device 9 is made of a metal film such as gold, lead or aluminum, or an organic film such as polyimide, and is composed of a plurality of organic films having different thicknesses. By changing the material and thickness of the scatterer device 9, the spot diameter of the spot beam at the position in the body can be adjusted.

The control computer 8 controls the settings of these devices.

Using these irradiation devices, three-dimensional irradiation is performed by the following method.

Now, it is assumed that a spot position (Xi, Yi, Zi) and an irradiation dose (Di) are written in the irradiation pattern table sent from the treatment planning computer (not shown) to the control computer 8. The spot irradiation is performed as follows based on the irradiation pattern table.

First, the incident energy of the particle beam and the thickness of the acrylic plate in the range shifter 7 are selected according to the position (Zi) of the deepest slice. At this time, the setting of the film of the scatterer device 9 is performed at the same time. Next, positions (Xi, Yi) [i = 1 to n] are selected for the deepest slice, and these positions (Xi, Yi) are selected by the scanning magnets 3a and 3b.
Irradiated in i). The ridge filter 6 expands the energy distribution of the monoenergetic particle beam so that the in-vivo range distribution corresponds to the slice width.

The irradiation dose at the position (Xi, Yi) on this slice is monitored by the dose monitor 4, and the scheduled dose (D
When the irradiation of i) is detected, the beam is stopped, and the irradiation position is changed to the next position (Xi + 1, Yi + 1) on the same slice by the scanning magnets 3a and 3b. When the irradiation of all points in this slice is completed, the acrylic thickness and the film setting of the scatterer in the range shifter 7 are changed, and irradiation of the next slice (Zi + 1) is performed. By repeating this sequentially for each slice, irradiation is performed three-dimensionally.

In this three-dimensional irradiation, the slice position (Z
i) and the film setting of the scatterer correspond to any slice position (Z
In i), the beam diameter is determined in advance by a preliminary experiment or calculation so that the beam diameter becomes the same.

Therefore, the influence of the scattering by the range shifter 7 and the effect of the scattering in the body are eliminated.
Therefore, even if a treatment plan in which an irradiation pattern is created with the same beam diameter is used, uniform irradiation can be performed as planned. That is, it is possible to perform a treatment capable of effectively killing cancer cells and reducing damage to normal cells.

In this embodiment, the film setting of the scatterer is
Although the slice position (Zi) is used as a parameter, the thickness may be used as a parameter for the thickness of the range shifter 7, which is an energy adjustment mechanism of a spot beam incident on the body. At the stage before the treatment, for example, the control computer 8
May receive the treatment plan data, determine the film setting value of the scatterer, and write it in advance in a data table describing the irradiation pattern.

FIG. 2 shows a third embodiment of a three-dimensional spot scanning method according to the present invention.
In the schematic configuration diagram of the three-dimensional irradiation apparatus, the same parts as those in FIG.

In FIG. 2, reference numeral 1 denotes a treatment bed;
1 is a three-dimensional irradiation device. The three-dimensional irradiation device 11 includes scanning magnets 3a and 3b, a dose monitor 4, a position monitor 5, a ridge filter 6, a range shifter 7, and a control computer 8.
And a focusing electromagnet 12.

Next, the configuration and function of each device of the three-dimensional irradiation apparatus shown in FIG. 2 will be described.

The scanning magnets 3a and 3b scan the spot beam incident on the scanning magnet at a point (X, Y) on a plane perpendicular to the beam axis in the affected part of the body.

The range shifter 7 controls the position (Z) in the beam axis direction within the affected part in the body.

The ridge filter 6 includes a range shifter 7
The internal range of the monoenergetic particle beam is expanded so as to correspond to the interval of the internal range switched by the above.

The converging electromagnet 12 can change the magnetic flux intensity by changing the amount of current in the coil, and can adjust the spot diameter of the spot beam at the position in the body.

The control computer 8 controls the settings of these devices.

Three-dimensional irradiation is performed by the following method using each irradiation device shown in FIG.

Now, it is assumed that a spot position (Xi, Yi, Zi) and an irradiation dose (Di) are written in the irradiation pattern table sent from the treatment planning computer (not shown) to the control computer 8. The spot irradiation is performed as follows based on the irradiation pattern table.

First, the incident energy of the particle beam and the thickness of the acrylic plate in the range shifter 7 are selected according to the position (Zi) of the deepest slice. At this time, the current value of the focusing electromagnet 12 is set at the same time. Next, the positions (Xi, Yi) [i = 1 to n] are selected for the deepest slice, and these positions (Xi, Yi) are selected by the scanning magnets 3a and 3b.
i, Yi). The ridge filter 6 expands the energy distribution of the monoenergetic particle beam so that the in-vivo range distribution corresponds to the slice width.

The irradiation dose at the position (Xi, Yi) on this slice is monitored by the dose monitor 4, and the scheduled dose (D
When the irradiation of i) is detected, the beam is stopped, and the irradiation position is changed to the next position (Xi + 1, Yi + 1) on the same slice by the scanning magnets 3a and 3b. When the irradiation of all the points in this slice is completed, the acrylic thickness in the range shifter 7 and the current value of the focusing electromagnet 12 are changed,
The irradiation of the next slice (Zi + 1) is performed. By repeating this sequentially for each slice, irradiation is performed three-dimensionally.

In this three-dimensional irradiation, the slice position (Z
i) and the current value of the electromagnet correspond to which slice position (Z
In i), the beam diameter is determined in advance by a preliminary experiment or calculation so that the beam diameter becomes the same.

Therefore, the effects of the scattering by the range shifter 7 and the effects of the scattering in the body are eliminated.
Therefore, even if a treatment plan in which an irradiation pattern is created with the same beam diameter is used, uniform irradiation can be performed as planned. That is, it is possible to perform a treatment that can effectively kill cancer cells and reduce damage to normal cells.

In this embodiment, the current value of the focusing electromagnet 12 is set using the slice position (Zi) as a parameter, but the thickness of the range shifter 7, which is an energy adjusting mechanism of the spot beam incident on the body, is used as a parameter. May go. Further, at the stage before the treatment, for example, at the stage when the control computer receives the treatment plan data, the current set value may be obtained and written in the data table in which the irradiation pattern is described in advance.

FIG. 3 shows a third embodiment of the present invention for a three-dimensional spot scanning method arranged in a treatment room.
In the schematic configuration diagram of the three-dimensional irradiation apparatus, the same parts as those in FIG.

In FIG. 3, reference numeral 1 denotes a treatment bed;
3 is a three-dimensional irradiation device. The three-dimensional irradiation device 13 includes scanning magnets 3a and 3b, a dose monitor 4, a position monitor 5, a ridge filter 6, a control computer 8, and a scatterer device 9.

The configuration and function of each device of the three-dimensional irradiation apparatus shown in FIG. 3 are the same as those of the first embodiment shown in FIG. 1, and the description is omitted here. However, the three-dimensional irradiation device 13 shown in FIG. 3 does not include the range shifter, and the change in the energy of the spot beam is not controlled by the irradiation device 1.
This is carried out by an accelerator (not shown) arranged upstream of 3 or a beam transport system.

Using the irradiation devices shown in FIG. 3, three-dimensional irradiation is performed by the following method.

Now, it is assumed that the spot position (Xi, Yi, Zi) and the irradiation dose (Di) are written in the irradiation pattern table sent from the treatment planning computer (not shown) to the control computer 8. The spot irradiation is performed as follows based on the irradiation pattern table.

First, the energy of the particle beam is selected according to the position (Zi) of the deepest slice, and the energy adjusted particle beam is introduced into the three-dimensional irradiation apparatus.
At this time, the setting of the film of the scatterer device 9 is performed at the same time.
Next, the position (Xi, Yi) [i =
1 to n], and these positions (Xi, Yi) are irradiated by the scanning magnets 3a and 3b. Due to the ridge filter 6, the monoenergetic particle beam becomes
The energy distribution is expanded so that the in-vivo range distribution corresponds to the slice width.

The irradiation dose at the position (Xi, Yi) on this slice is monitored by the dose monitor 4, and the scheduled dose (D
When the irradiation of i) is detected, the beam is stopped, and the irradiation position is changed to the next position (Xi + 1, Yi + 1) on the same slice by the scanning magnets 3a and 3b. When the irradiation of all the points in this slice is completed, the control computer 8 sends an energy change command to the accelerator or the control device of the beam transport system to change the beam energy, and also changes the film setting of the scatterer device 9. , The next slice (Zi + 1) is irradiated. By repeating this sequentially for each slice, irradiation is performed three-dimensionally.

In this three-dimensional irradiation, the slice position (Z
The correspondence between i) and the film setting of the scatterer device 9 is determined in advance by a preliminary experiment or calculation so that the beam diameter is the same at any slice position (Zi).

The beam diameter adjustment described here can be performed more easily and in a shorter time than the case where the beam diameter is adjusted in the beam transport system, and the influence of scattering in the body can be removed. Therefore, the time for fixing the patient is shortened, the burden on the patient is reduced, and uniform irradiation can be performed in accordance with the treatment plan.

In this embodiment, the film setting of the scatterer device 9 is performed using the slice position (Zi) as a parameter, but the energy of the spot beam incident on the body may be used as a parameter. Further, at the stage before the treatment, for example, at the stage when the control computer 8 receives the treatment plan data, the film setting value of the scatterer device 9 is obtained and written in advance in the data table in which the irradiation pattern is written. Is also good.

FIG. 4 shows a third embodiment of the three-dimensional spot scanning method according to the present invention for use in a three-dimensional spot scanning method.
In the schematic configuration diagram of the three-dimensional irradiation apparatus, the same parts as those in FIG.

In FIG. 4, reference numeral 14 denotes a treatment bed;
Reference numeral 15 denotes a three-dimensional irradiation device. The treatment bed 14 is driven by a driving mechanism (not shown) to set the irradiation position of the spot beam in the body X.
It is possible to move in the direction and the Y direction. The three-dimensional irradiation device 15 includes a dose monitor 4, a position monitor 5, a ridge filter 6, a range shifter 7, a control computer 8, and a scatterer device 9.

Since the configuration and function of each device of the three-dimensional irradiation apparatus shown in FIG. 4 are the same as those of the first embodiment shown in FIG.
Here, the description is omitted. However, 3 shown in FIG.
The three-dimensional irradiation device 15 does not include a scanning magnet, and the irradiation position of the spot beam in the body is changed using a driving mechanism attached to the treatment bed 14.

Using the respective irradiation devices shown in FIG. 4, three-dimensional irradiation is performed by the following method.

Now, it is assumed that a spot position (Xi, Yi, Zi) and an irradiation dose (Di) are written in the irradiation pattern table sent from the treatment planning computer (not shown) to the control computer 8. The spot irradiation is performed as follows based on the irradiation pattern table.

First, the incident energy of the particle beam and the thickness of the acrylic plate in the range shifter 7 are selected according to the position (Zi) of the deepest slice. At this time, the film setting of the scatterer device 9 is performed at the same time. Next, with respect to the deepest slice, a position (Xi, Yi) [i = 1 to n] is selected, and the treatment bed 14 is moved by a drive mechanism (not shown) to irradiate these positions (Xi, Yi). Is done. The energy distribution of the particle beam that was monoenergetic at the entrance of the three-dimensional irradiation device 15 is expanded by the ridge filter 6 so that the in-vivo range distribution corresponds to the slice width.

The irradiation dose at the position (Xi, Yi) on this slice is monitored by the dose monitor 4, and the scheduled dose (D
When the irradiation of i) is detected, the beam is stopped, and the irradiation position is changed to the next position (Xi + 1, Yi + 1) on the same slice by moving the treatment bed 14. When the irradiation of all points in this slice is completed, the acrylic thickness in the range shifter 7 and the film setting of the scatterer device are changed, and irradiation of the next slice (Zi + 1) is performed. By repeating this sequentially for each slice, irradiation is performed three-dimensionally.

In this three-dimensional irradiation, the slice position (Z
The correspondence between i) and the film setting of the scatterer device is determined in advance by a preliminary experiment or calculation so that the beam diameter is the same at any slice position (Zi).

Therefore, the effects of the scattering by the range shifter 7 and the effects of the scattering in the body are eliminated.
Therefore, even if a treatment plan in which an irradiation pattern is created with the same beam diameter is used, uniform irradiation can be performed as planned. That is, a treatment capable of effectively killing cancer cells and reducing damage to normal cells can be performed.

In this embodiment, the film setting of the scatterer device 9 is performed using the slice position (Zi) as a parameter, but the energy of the spot beam incident on the body may be used as a parameter. Further, at the stage before the treatment, for example, at the stage when the control computer receives the treatment plan data, the film setting value of the scatterer device may be obtained and written in a data table describing the irradiation pattern in advance.

Next, a fifth embodiment of the present invention will be described. Since the configuration of the apparatus is the same as that of the first embodiment, it will be described here with reference to FIG.

In the present embodiment, the irradiation pattern table sent from the treatment planning computer (not shown) to the control computer 8 includes a spot position (Xi, Yi, Zi), an irradiation dose (Di), and a beam diameter (Ri). ) Is written. Here, the spot position is determined at the stage of treatment planning in FIG.
As shown by, for each slice, that is, for each Zi, the irradiation area is grouped into the vicinity of the boundary of the irradiation area and other areas, and the spot positions are rearranged for each group. Are set smaller than the spot diameter of the group.

In the present invention, three-dimensional irradiation is performed as follows by the following method.

First, the incident energy of the particle beam and the thickness of the acrylic plate in the range shifter 7 are selected according to the position (Zi) of the deepest slice. At this time, the setting of the film of the scatterer device 9 is performed in accordance with the beam diameter (Ri) of the irradiation pattern table. Next, spot irradiation at the position (Xi, Yi) on the deepest slice is performed. Here, the spot positions (Xi, Yi) are divided into the vicinity of the irradiation area boundary and the center plane of the irradiation area (hereinafter, other areas), and irradiation is performed from the spots belonging to the group near the irradiation area boundary first. In this group, the set beam diameter Ri is the same.

When the spot irradiation of this group is completed,
The irradiation is performed after moving to the spot position of another group and changing the beam diameter Ri. When the irradiation of all the points in this slice is completed, the acrylic thickness in the range shifter 7 and the film setting of the scatterer device are changed, and the next slice (Zi +
The irradiation of 1) is performed. By repeating this sequentially for each slice, irradiation is performed three-dimensionally.

In this embodiment, the spot diameter at the boundary near the irradiation area is controlled so as to be smaller than the other areas. Therefore, as shown in FIG.
It is possible to improve the cut of the irradiation dose at the irradiation area boundary.

[0108] Therefore, it is possible to reduce the exposure to the vicinity of the irradiation area boundary and suppress the damage to normal cells.

Further, by sequentially irradiating the beam from the group of spot positions located near the irradiation area boundary, the number of times of changing the beam diameter Ri can be reduced, and the dead time associated with the film change of the scatterer device 9 is reduced. Can be done.

Therefore, the treatment time can be shortened, and the pain associated with fixing the patient to the treatment bed or treatment chair for a long time can be suppressed.

As in this embodiment, by maintaining the beam diameter as a parameter in the irradiation pattern table, the arbitrariness of the irradiation pattern can be expanded, and even for a complicated affected part shape, the dose around the irradiation area is uniform. Can be realized.

Although the irradiation area shown in FIG. 6 has been described in the case where the treatment area is present up to the center of the affected part, normal cells may be present in the center depending on the affected part. In such a case, it is possible to reduce the exposure to the normal cells by irradiating a beam having a small beam diameter to the vicinity of the boundary with the normal cells in the center in addition to the periphery of the irradiation area.

In this embodiment, the adjustment of the beam diameter is performed by the adjustment mechanism composed of the scatterer. However, another beam diameter adjustment mechanism composed of a converging electromagnet is arranged to perform irradiation while adjusting the same beam diameter. Thereby, a similar effect can be achieved.

FIG. 7 is a schematic configuration diagram of a particle beam irradiation apparatus arranged in a treatment room according to a sixth embodiment of the present invention. The same parts as those in FIG. explain.

In FIG. 7, reference numeral 1 denotes a treatment bed;
Reference numeral 6 denotes a particle beam irradiation device. The particle beam irradiation device 16 includes deflection magnets 17a and 17b, a dose monitor 4, a position monitor 5,
It comprises a range shifter 7, a control computer 8, and a scatterer device 9.

Next, the configuration and function of each device of the three-dimensional irradiation apparatus shown in FIG. 7 will be described.

The deflecting magnets 17a and 17b deflect the spot beam incident on the scanning magnet to a point (X, Y) on a plane perpendicular to the beam axis in the affected part of the body.

Here, the deflecting magnets 17a and 17b are
An X-direction deflection magnet that deflects the beam in the X direction and a Y-direction deflection magnet that deflects the beam in the Y direction.

The range shifter 7 controls the position (Z) in the beam axis direction in the affected part of the body. This range shifter 7
Is composed of a plurality of acrylic plates having different thicknesses, and by appropriately combining these acrylic plates, the beam energy passing through the range shifter 7, that is, the in-vivo range can be changed stepwise.

The scatterer device 9 is made of a metal film such as gold, lead or aluminum or an organic film such as polyimide.
It is composed of a plurality of organic films having different thicknesses. By changing the material and thickness of the scatterer device 9, the spot diameter of the spot beam at the position in the body can be adjusted.

The control computer 8 controls the settings of these devices.

Using these irradiation devices, particle beam irradiation is performed by the following method.

In the control computer 8, a spot position (X, Y, Z) corresponding to the position of the affected part, a beam diameter (R) and an irradiation dose (D) corresponding to the shape of the affected part are written. And The setting of each device is performed as follows according to these parameters.

First, the incident energy of the particle beam and the thickness of the acrylic plate in the range shifter 7 are selected according to the position (Z) in the beam axis direction. In addition, the spot position (X,
The setting of the deflection magnets 17a and 17b is performed according to Y). Further, the setting of the film of the scatterer device 9 is performed according to the beam diameter (R).

Next, the beam is irradiated, and when the irradiation of the predetermined dose (D) is detected, the beam is stopped and the treatment is ended.

By using the beam diameter adjusting device made of a scatterer as described above, the beam size can be easily and accurately adjusted to the shape of the affected part, and the size (several centimeters) can be reduced.
Can be performed without using a complicated control system.

In this embodiment, a ridge filter for shaping the irradiation area in the beam axis direction is not used, but a ridge filter may be used if shaping is necessary.

If the energy of the particle beam introduced into the particle beam irradiation apparatus can be adjusted with high accuracy on the accelerator side or in the beam transport system, the position in the beam axis direction (Z) can be set on the upstream side. Often, a range shifter is not required.

Further, the control of the spot position (X, Y) may be performed by moving the bed using a treatment bed provided with a drive mechanism without using a deflection magnet. In the embodiment described above, the scatterer device 9 is arranged between the position monitor 5 and the ridge filter 6, but it can be arranged at another place.

The scattering effect of the scatterer by the film is represented by a function of the film thickness and the distance from the affected part. In addition, different scattering effects are exhibited depending on the material of the inserted film.

In general, in the case of a metal film, the effect on energy, that is, the range (range) can be reduced, and a large scattering effect can be obtained.

According to the calculation of the carbon beam by the present inventors, for example, the same scattering effect as when a 10 cm acrylic plate is inserted into a range shifter placed 40 cm upstream of the affected part from the affected part is obtained 50 cm and 200 cm upstream from the affected part. 0.25cm and 0.025c respectively
It is obtained by a lead film having a thickness of m. Other acrylic thicknesses can be accommodated by inserting lead films of different thickness.

Further, the organic film has the advantage that it is strong even if the film thickness is small, and that it is easy to handle. The scattering effect of the organic film is smaller than that of the metal film. According to calculations by the present inventors, the same scattering effect as when a 10 cm acrylic plate is inserted into a range shifter placed 40 cm upstream from the affected part is obtained by the organic film 0.7 cm thick placed 200 cm upstream of the beam. be able to.

The scattering effect can be further enhanced by coating the surface of the organic film with a metal, taking advantage of the fact that the organic film is easy to handle.

FIG. 8 shows a third embodiment of the three-dimensional spot scanning method according to the present invention for use in a three-dimensional spot scanning method.
In the schematic configuration diagram of the three-dimensional irradiation apparatus, the same parts as those in FIG.

In FIG. 8, reference numeral 1 denotes a treatment bed;
Reference numeral 8 denotes a three-dimensional irradiation device. The three-dimensional irradiation device 18 includes scanning magnets 3a and 3b, a dose monitor 4, a position monitor 5, a ridge filter 6, a range shifter 7, and a control computer 8.
And scatterer devices 19, 20, and 21.

The scatterer device 19 is made of a metal film or an organic film, and is composed of a plurality of organic films having different thicknesses. Further, the scatterer devices 20 and 21 have the same configuration as the scatterer device 19.

This embodiment utilizes the fact that the scattering effect varies depending on the distance from the affected part in addition to the material and thickness of the film. Even with the scatterer device having the same configuration, the beam diameter is greatly expanded by the scatterer device 19 placed far from the affected part.

As described above, by providing some scatterer devices and changing their arrangement positions, the range in which the beam diameter can be expanded can be increased.

FIG. 9 is a schematic configuration diagram showing a range shifter according to the eighth embodiment of the present invention.

In FIG. 9, 31a, 31b, 31c.
... have different thicknesses, for example, acrylic plates, 32a, 32b,
32c are films of, for example, lead having different thicknesses, 33 is an outer container, 34a, 34b, 34c, and 35a, 3
Reference numerals 5b, 35c... Indicate air cylinders.

In this embodiment, the beam diameter is adjusted as follows. That is, one or more acrylic plates 3 specified by a control input signal from the control computer.
1 is inserted on the beam axis by the air cylinder 34.
At this time, a combination of the lead films 32 is selected according to the combination of the selected acrylic plates, and the lead film is inserted on the beam axis by the air cylinder 35.

In this case, lead has a large scattering effect as compared with acrylic, so that the influence of a change in beam diameter due to the acrylic plate can be adjusted with a thin film thickness.

In the embodiment shown in FIG. 9, since the beam adjusting mechanism is integrated with the range shifter, it is possible to arrange the irradiation device without increasing the size. In addition, since the insertion of the acrylic plate and the lead film can be controlled by the same input signal line, cable wiring and the like can be reduced.

FIG. 10 is a schematic configuration diagram showing a range shifter according to a ninth embodiment of the present invention.

In FIG. 10, 41a, 41b, 41c
... are acrylic plates of different thicknesses, 43 is an outer container,
44a, 44b, 44c... Are air cylinders.

Here, films 42a, 42b, 42c... Made of, for example, lead are attached to each acrylic plate. Further, the thickness of the lead film attached to the acrylic plate is selected so that the beam diameter at the affected part becomes the same.

In this embodiment, the beam diameter is adjusted as follows. That is, one or more acrylic plates 4 specified by a control input signal from the control computer.
1 is inserted on the beam axis by the air cylinder 44.
At this time, the lead film attached to the acrylic plate is simultaneously inserted on the beam axis.

In the embodiment shown in FIG. 10, a lead film is attached to an acrylic plate, and an air cylinder for the lead film is not required. Therefore, cost reduction and space saving can be achieved. Further, since the lead film is moved in and out in conjunction with the acrylic plate, the control mechanism can be simplified and the cost can be reduced.

In the above-described embodiment of the present invention, the three-dimensional irradiation apparatus and the three-dimensional irradiation method in the spot scanning method have been described. With respect to the two-dimensional irradiation method, it is possible to realize uniform irradiation and irradiation that reduces the dose around the irradiation area in the same manner.

[0151]

As described above, according to the present invention, uniform and accurate irradiation over a three-dimensional irradiation area can be easily performed by the beam diameter adjusting mechanism.

In addition, irradiation can be performed by changing the spot diameter for each irradiation spot, so that the irradiation dose is uniform over the irradiation area and the irradiation dose can be sharply cut at the boundary of the irradiation area. Can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a three-dimensional irradiation apparatus for a three-dimensional spot scanning method according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a three-dimensional irradiation apparatus for a three-dimensional spot scanning method according to a second embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a three-dimensional irradiation apparatus for a three-dimensional spot scanning method according to a third embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a three-dimensional irradiation apparatus for a three-dimensional spot scanning method according to a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating an example of grouping of irradiation spots according to a fifth embodiment of the present invention.

FIG. 6 is a view showing an irradiation dose distribution in a certain slice by three-dimensional spot scanning irradiation in the embodiment.

FIG. 7 is a schematic configuration diagram of a three-dimensional irradiation apparatus for a three-dimensional spot scanning method according to a sixth embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a three-dimensional irradiation apparatus for a three-dimensional spot scanning method according to a seventh embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a range shifter according to an eighth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram showing a range shifter according to a ninth embodiment of the present invention.

FIG. 11 shows a conventional 3D spot scanning method.
The schematic block diagram which shows a three-dimensional irradiation apparatus.

FIG. 12 is a view showing an irradiation dose distribution in a certain slice by three-dimensional spot scanning irradiation in the same device.

[Explanation of symbols]

1, 14 ... treatment bed 2, 10, 11, 13, 15, 18 ... three-dimensional irradiation device 3a, 3b ... scanning magnet 4 ... dose monitor 5 ... position monitor 6 ... ridge filter 7 ... range shifter 8 ... control computer 9, 19 , 20, 21 ... Scatterer device 12 ... Focusing electromagnet 16 ... Particle beam irradiation device 17a, 17b ... Deflection magnet 31 (31a, 31b ...), 41 (41a, 41b ...)
... Acrylic plate 32 (32a, 32b ...), 42 (42a, 42b ...)
... Lead films 33, 43 ... Outer container 34 (32a, 32b ...), 35 (35a, 35b)
...), 44 (44a, 44b ...) ... cylinder

Claims (16)

[Claims] 1. A particle beam irradiation method for controlling the energy and position of a particle beam spot beam to irradiate an irradiated part by controlling a beam diameter by a beam diameter adjusting means capable of switching a plurality of spot beam diameters. A method for irradiating a particle beam, comprising performing irradiation. 2. A particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated.
A particle beam irradiation method characterized in that irradiation is performed by controlling a beam diameter by a beam diameter adjusting means capable of switching a plurality of spot beam diameters. 3. A particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated.
Irradiation is performed by controlling the energy or the position in the beam axis direction among the three-dimensional irradiation positions or the state of the energy switching mechanism as one of the parameters by a beam diameter adjusting means capable of switching a plurality of spot beam diameters. Particle beam irradiation method. 4. A particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated.
A particle beam irradiation method, wherein an irradiation area is divided into a plurality of groups, and irradiation is performed by controlling a beam diameter corresponding to each group by a beam diameter adjusting means capable of switching a spot beam diameter to a plurality. 5. A spot position near an irradiation area boundary is set as one of the groups, and a diameter of a spot beam for irradiating the spot near the boundary is smaller than a spot at a center position of the irradiation area. The particle beam irradiation method according to claim 4, wherein the irradiation is performed while controlling the irradiation of the particle beam. 6. A particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to conform to the shape and size of a portion to be irradiated.
A particle beam irradiation method, wherein an irradiation area is divided into a plurality of groups, and irradiation is performed sequentially from spots in the same group. 7. A particle beam irradiation method for sequentially controlling the energy and position of a particle beam spot beam to perform three-dimensional irradiation so as to match the shape and size of an irradiation target,
Irradiation areas are divided into a plurality of groups, the beam diameter is controlled by a beam diameter adjusting means capable of switching the spot beam diameter to a plurality of groups, and irradiation is sequentially performed from spots in the same group. Line irradiation method. 8. The beam diameter adjusting means according to claim 1, wherein the beam diameter is controlled by moving at least one scatterer on and off the beam axis. The particle beam irradiation method according to the above. 9. The particle beam irradiation method according to claim 1, wherein said beam diameter adjusting means controls a beam diameter by a converging electromagnet. 10. A mechanism for switching the energy of a particle beam spot beam to a plurality of positions and a mechanism for switching an irradiation position of the particle beam, controlling the energy and position of the particle beam spot beam to irradiate an irradiated portion. A beam diameter adjusting mechanism capable of switching a spot beam diameter to a plurality of spot beam diameters. 11. A mechanism for switching the energy of a particle beam spot beam to a plurality, a mechanism for switching an irradiation position of the particle beam, and changing the energy of the particle beam spot beam and the irradiation position to the shape and size of a portion to be irradiated. In a three-dimensional particle beam irradiation apparatus provided with a control computer for sequentially controlling them so as to match each other, a beam diameter adjusting mechanism capable of switching a plurality of spot beam diameters, a three-dimensional irradiation position or the value of the energy, or the energy switching And a mechanism for controlling the beam diameter adjusting mechanism using a state of the mechanism as one of parameters. 12. A mechanism for switching the energy of a particle beam spot beam to a plurality, a mechanism for switching an irradiation position of the particle beam, and changing the energy of the particle beam spot beam and the irradiation position to the shape and size of a portion to be irradiated. In a three-dimensional particle beam irradiation apparatus including a control computer for sequentially controlling the beam spots so as to match each other, a beam diameter adjusting mechanism capable of switching a plurality of spot beam diameters, and the energy switching using a three-dimensional irradiation position and a spot beam diameter as parameters. A particle beam irradiation apparatus comprising a mechanism, an irradiation position switching mechanism, and a control mechanism for controlling a spot beam diameter adjusting mechanism. 13. The apparatus according to claim 1, wherein the beam diameter adjusting mechanism is constituted by a plurality of scatterer devices.
13. The particle beam irradiation apparatus according to any one of 0 to 12. 14. The particle beam irradiation apparatus according to claim 10, wherein said beam diameter adjusting mechanism is constituted by a focusing electromagnet. 15. The particle beam irradiation apparatus according to claim 10, wherein a range shifter is used as a mechanism for switching the energy of the particle beam spot beam. 16. A range shifter comprising one or more plates, and a plate or a film of a different material from the plate having a thickness corresponding to the material or the thickness of the plate is attached to the plate. The particle beam irradiation apparatus according to claim 15, wherein