Charged particle beam apparatus and method for operating the same

• US 6,316,776 B1
• Filed: 09/02/1999
• Issued: 11/13/2001
• Est. Priority Date: 08/30/1996
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tadokoro, Masahiro, Akiyama, Hiroshi, Matsuda, Koji, Hiramoto, Kazuo, Norimine, Tetsuro
• Primary Examiner(s): NGUYEN, KIET TUAN
• Application Number:
  US09/388,437
• Time in Patent Office: 803 Days
• Field of Search: 250/492.3, 250/505.1, 250/398, 315/501, 315/505, 315/507
• US Class Current: 250/492.3
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 2005/1095 Elements inserted into the radiation path within the system, e.g. filters or wedges
• CPC Class Codes: A61N 5/1042 with spatial modulation of the radiation beam within the treatment head
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam

Abstract

A method of irradiation with a charged particle beam and an irradiation apparatus wherein the charged particle beam supplied from an accelerator and extracted from the irradiation apparatus. The irradiation apparatus includes an electromagnet for scanning with the charged particle beam. The method includes the steps of stopping the extraction of the charged particle beam from the irradiation apparatus, changing an irradiation point of the charged particle beam by controlling the electromagnet under a condition when the extraction is stopped, and resuming the extraction of the charged particle beam from the irradiation apparatus after changing the irradiation point.

Claims

1. A method of irradiation with a charged particle beam, which is supplied from an accelerator to an irradiation apparatus comprising an electromagnet, and extracted from the irradiation apparatus for scanning with the charged particle beam, comprising the steps of:

stopping the extraction of the charged particle beam from the irradiation apparatus by stopping the supply of the charged particle beam from the accelerator to the irradiation apparatus;

changing an irradiation region of the charged particle beam by controlling the electromagnet under a condition when the extraction is stopped; and

resuming the extraction of the charged particle beam from the irradiation apparatus after changing the irradiation region by resuming the supply of the charged particle beam from the accelerator;

wherein if the charged particle beam, which is circulating in the accelerator during the stopping of the extraction of the charged particle beam from the irradiation apparatus, is sufficient for irradiation at a new irradiation region after the changing of the irradiation region, a residual charged particle beam in the accelerator is supplied to the irradiation apparatus from the accelerator without supplying charged particles from a charged particle generator; and

wherein if the residual charged particle beam in the accelerator is insufficient for irradiation at the new irradiation region after the changing of the irradiation region, supply of the residual charged particle beam in the accelerator to the irradiation apparatus from the accelerator is resumed after supplying of charged particles from the charged particle generator to the accelerator.

2. A method of irradiation with a charged particle beam as claimed in claim 1, wherein supplying of the charged particle beam from the accelerator to the irradiation apparatus is initiated by charging a high-frequency electromagnetic field to the charged particle beam which is circulating in said accelerator, and terminating the supplying of the charged particle beam from the accelerator to said irradiation apparatus by stopping the charging of the high-frequency electromagnetic field to the charged particle beam.

3. A method of irradiation with a charged particle beam as claimed in claim 1, wherein the step of changing the irradiation region is effected after an irradiation dose of the charged particle beam to the irradiation region has reached a pre-set value.

4. A method of irradiation with a charged particle beam as claimed in claim 1, wherein when irradiation of an affected part as the irradiation region is effected, the charged particle beam is extracted from the irradiation apparatus when the affected part is substantially stationary.

5. An accelerator system comprising:

an accelerator for supplying a charged particle beam;

an irradiation apparatus, which is provided with an electromagnet for scanning with the charged particle beam, for extracting the charged particle beam supplied from said accelerator; and

a controller for stopping the extraction of the charged particle beam from the irradiation apparatus to an irradiation region by stopping supply of the charged particle beam from said accelerator, for changing the irradiation region of the charged particle beam by controlling the electromagnet under a condition when the extraction is stopped, and for resuming the extraction of the charged particle beam from the irradiation apparatus after changing the irradiation region by resuming the supply of the charged particle beam from the accelerator;

wherein the controller operates so that if the charged particle beam, which is circulating in the accelerator during the stopping the of extraction of the charged particle beam from the irradiation apparatus, is sufficient for irradiation at a new irradiation region after the changing of the irradiation region, the supply of the charged particle beam in the accelerator to the irradiation apparatus is resumed; and

wherein if the charged particle beam, which is circulating in the accelerator during the stopping of the extraction of the charged particle beam from the irradiation apparatus is insufficient for irradiation at the new irradiation region after the changing of the irradiation region, the supply of the charged particle beam in the accelerator to the irradiation apparatus is resumed after supplying charged particles from a charged particle generator to the accelerator.

6. An accelerator system as claimed in claim 5, wherein the accelerator comprises a high-frequency charging apparatus for generating a high-frequency electromagnetic field, the controller operates so that the extraction of the charged particle beam from the irradiation apparatus is initiated by supplying the charged particle beam from the accelerator by generating a high-frequency electromagnetic field with the high-frequency charging apparatus, and the control enables termination of the extraction of the charged particle beam from the irradiation apparatus by stopping of the supply of the charged particle beam from the accelerator by stopping of the generation of the high-frequency electromagnetic field.

7. An accelerator system as claimed in claim 5, further comprising an irradiation dose monitor for measuring an irradiation dose of the charged particle beam at the irradiation region, and the controller operates so the changing of the irradiation region is effected after the irradiation dose of the charged particle beam to the irradiation region reaches a pre-set value.