Radiant energy – Irradiation of objects or material – Ion or electron beam irradiation
Reexamination Certificate
1998-09-02
2001-07-31
Arroyo, Teresa M. (Department: 2881)
Radiant energy
Irradiation of objects or material
Ion or electron beam irradiation
C250S398000
Reexamination Certificate
active
06268610
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a charged-particle beam irradiation apparatus, a charged-particle beam rotary irradiation system, and a charged-particle beam irradiation method which are adapted to a therapeutic apparatus using a charged-particle beam or the like.
2. Description of the Related Art
FIG. 16
shows an example of a charged-particle beam rotary irradiation system that is a conventional therapeutic apparatus using a charged-particle beam disclosed in, for example, a report written by Pedroni of Switzerland (Medical Physics, Vol. 22, PP.37-53).
In the drawing, there are shown a charged-particle beam rotary irradiation system
100
, a particle accelerator
1
, a transporting electromagnet
3
, an energy degrader
5
, a proton beam
7
, a beam stopper
9
, a rotating gantry
10
, deflective electromagnets
11
,
13
, and
19
, convergent electromagnets
15
, a scanning electromagnet.
17
, an energy degrader
21
, a dose/position monitor
23
, a patient
25
, a radiation table
27
, and an axis of rotation of the gantry
29
.
A proton beam generated by the accelerator
1
is transported by the transporting electromagnet
3
, passed by the energy degrader
5
serving as an initial-stage energy changing means, and thus recomposed into a proton beam
7
having given energy level. The proton beam
7
is deflected upward from a horizontal direction by the first deflective electromagnet
11
, and then returned to the horizontal direction by the deflective electromagnet
13
.
The proton beam
7
is converged by the convergent electromagnets
15
, and swept vertically by the scanning electromagnet
17
. The swept proton beam is deflected immediately downward by the last deflective electromagnet
19
, and then irradiated to the patient
25
via the energy degrader for fine adjustment
21
and the dose/position monitor
23
.
Herein, the electromagnets
11
,
13
,
15
,
17
, and
19
, energy degrader
21
, and monitor
23
are integrated into one unit, thus forming an irradiation gantry. The irradiation gantry can make a turn about the axis of rotation
29
and is referred to as the rotating gantry
10
.
The spot of the proton beam irradiated to the patient
25
is shifted parallel to an X-axis direction alone shown in
FIG. 16
by means of the scanning electromagnet
17
and deflective electromagnet
19
. Scanning the patient in a Y-axis direction which is required for a therapeutic procedure is achieved by moving the radiation table
27
. Scanning the patient
25
in a depth direction (Z-axis direction) of the patient
25
is achieved by adjusting the energy of the proton beam using the energy degrader
21
.
The length of the rotating gantry
10
in the longitudinal direction thereof is approximately 10 m. A length in the gantry where the proton beam is displaced away from the gantry rotation axis
29
is approximately 2 m.
In the thus-configured conventional modality using a charged-particle beam, spot scanning in which the spot of a beam is shifted parallel to one axial direction alone (the X-axis direction in the above example) can solely be realized. The patient
25
must be moved in the Y-axis direction by moving the table
27
during treatment. This poses a problem that the movement gives the patient senses of discomfort and fear and results in displacement of a radiation area.
Moreover, in the above conventional modality, since the spot of a beam parallel to an axis of incidence thereof is shifted, the scanning electromagnet
17
must be placed upstream of the deflective electromagnet
19
. Accordingly the deflective electromagnet
19
for deflecting a proton beam, i.e. the charged-particle beam, which is swept vertically by the scanning electromagnet
17
, becomes large in size. As a result, the total weight of the treatment rotating gantry
10
becomes 100 tons or more. Moreover, since the deflective electromagnet
19
is so large as to have magnetic poles of several tens centimeters wide, when a superconducting magnet is employed, there arises a problem of very high manufacturing cost.
SUMMARY OF THE INVENTION
The present invention attempts to solve the aforesaid problems. An object of the present invention is to provide a charged-particle beam irradiation apparatus, charged-particle beam rotary irradiation system, and charged-particle beam irradiation method realizing spot scanning, in which the spot of a beam parallel to an axis of incidence thereof is shifted two axial directions within a radiation area, without the necessity of moving a table, and employing a rotating gantry of a compact and lightweight design.
For accomplishing the above object, according to the present invention, there is provided a charged-particle beam irradiation apparatus comprising a scanning field generating means for generating a scanning field composed of a pair of fields effective in bending a charged-particle beam by the same angle in mutually opposite directions, and a rotating means for rotating the scanning field generating means with the axis of incidence of the charged-particle beam as a center.
Moreover, according to the present invention, there is provided a charged-particle beam irradiation apparatus characterized in that the scanning field generating means generates magnetic fields.
Moreover, according to the present invention, there is provided a charged-particle beam irradiation apparatus characterized in that the scanning field generating means generates electric fields.
Moreover, according to the present invention, there is provided a charged-particle beam rotary irradiation system comprising: a deflecting means for deflecting a charged-particle beam perpendicularly to a radiation plane; a charged-particle beam irradiation apparatus that includes a scanning field generator, located downstream of the deflecting means, for generating a scanning field composed of a pair of fields effective in bending the charged-particle beam by the same angle in mutually opposite directions, and a rotator for rotating the scanning field generator with the axis of incidence of the charged-particle beam as a center, and that sweeps the charged-particle beam deflected by the deflecting means for the purpose of scan; a charged-particle beam energy adjusting means interposed between the charged-particle beam irradiation apparatus and an irradiated subject; and a rotary motion means for rotating at least the deflecting means and charged-particle beam irradiation apparatus in one united body.
Moreover, according to the present invention, the charged-particle beam falls on the deflecting means from the direction of the axis of rotation of the rotary motion means. The deflecting means includes three deflective electromagnets for deflecting an incident charged-particle beam three times by 90° with respect to a direction parallel to the radiation plane so that the charged-particle beam is perpendicular to the radiation plane. The irradiated subject is positioned on the axis of rotation of the rotary motion means.
Moreover, according to the present invention, there is provided a charged-particle beam rotary irradiation system characterized in that the deflective electromagnets included in the deflecting means are realized with superconducting electromagnets.
Moreover, according to the present invention, there is provided a charged-particle beam irradiation system comprising: a charged-particle beam irradiation apparatus that includes a scanning field generator for generating a scanning field composed of a pair of fields effective in bending a charged-particle beam by the same angle in mutually opposite directions, and a rotator for rotating the scanning field generator with the axis of incidence of the charged-particle beam as a center, and that sweeps the charged-particle beam for the purpose of scan; a charged-particle beam energy adjusting means, interposed between the charged-particle beam irradiation apparatus and irradiated subject, for adjusting the energy of a charged-particle beam; a dose/position measuring means, interposed between the ch
Arroyo Teresa M.
Mitsubishi Denki & Kabushiki Kaisha
Smith II Johnnie L
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Charged-particle beam irradiation apparatus,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Charged-particle beam irradiation apparatus,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Charged-particle beam irradiation apparatus,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2465381