Ion beam therapy system and its couch positioning method

• US 7,405,407 B2
• Filed: 02/09/2007
• Issued: 07/29/2008
• Est. Priority Date: 01/24/2005
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Nagamine, Yoshihiko, Akiyama, Hiroshi, Hiramoto, Kazuo, Smith, Alfred, Newhauser, Wayne
• Primary Examiner(s): Vanore; David A.
• Assistant Examiner(s): SOUW, BERNARD E
• Application Number:
  US11/704,372
• Publication Number:
  US 20070215819A1
• Time in Patent Office: 536 Days
• Field of Search: 250/492.3, 250/370.09
• US Class Current: 250/370.09
• CPC Class Codes: A61N 2005/1061 using an x-ray imaging system having a separate imaging source
• CPC Class Codes: A61N 2005/1087 Ions; Protons
• CPC Class Codes: A61N 5/1049 for verifying the position of the patient with respect to the radiation beam
• CPC Class Codes: A61N 5/1069 Target adjustment, e.g. moving the patient support

Abstract

A therapy system using an ion beam, which can shorten the time required for positioning a couch (patient). The therapy system using the ion beam comprises a rotating gantry provided with an ion beam delivery unit including an X-ray tube. An X-ray detecting device having a plurality of X-ray detectors can be moved in the direction of a rotation axis of the rotating gantry. A couch on which a patient is lying is moved until a tumor substantially reaches an extension of an ion beam path in the irradiating unit. The X-ray tube is positioned on the ion beam path and the X-ray detecting device is positioned on the extension of the ion beam path. With rotation of the rotating gantry, both the X-ray tube emitting an X-ray and the X-ray detecting device revolve around the patient. The X-ray is emitted to the patient and detected by the X-ray detectors after penetrating the patient. Tomographic information of the patient is formed based on signals outputted from the X-ray detectors. Information for positioning the couch is generated by using the tomographic information.

Claims

1. A therapy system using an ion beam, in which an ion beam for treatment is delivered to an irradiation target, said therapy system comprising:

a rotating gantry;

a beam generator for generating said ion beam;

a beam delivery unit mounted to said rotating gantry and delivering said ion beam;

an X-ray generator revolving about a rotation axis of said rotating gantry with rotation of said rotating gantry and emitting X-ray at a plurality of rotation angles of said rotating gantry;

a plurality of X-ray detectors revolving about the rotation axis of said rotating gantry with rotation of said rotating gantry for detecting the X-ray emitted from said X-ray generator and outputting X-ray detection signals; and

an image information forming unit for forming three-dimensional image information of said irradiation target by using information obtained based on the X-ray detection signals from said plurality of X-ray detectors obtained upon rotation of said rotating gantry, position information of said X-ray generator emitting the X-ray and position information of said plurality of X-ray detector outputting the X-ray detection signals.

2. A therapy system according to claim 1, wherein said X-ray generator is mounted in said beam delivery unit revolving about the rotation axis of said rotating gantry with the rotation of said rotating gantry, and is movable between a first position lying in said beam path and a second position away from said beam path.

3. A therapy system according to claim 1, wherein said beam delivery unit includes a moving device for moving said X-ray generator between said first position and said second position.

4. A therapy system according to claim 1, further comprising a couch capable of supporting said irradiation target and being positioned on an extension of said radiation path.

5. A therapy system according to claim 4, further comprising a positioning information generator for generating information for positioning said couch by using said three-dimensional image information and tomographic information of said irradiation target used at a treatment plan for said irradiation target, and a couch movement controller for controlling movement of said couch by using the positioning information.

6. A therapy system using an ion beam according to claim 2, further comprising a couch capable of supporting said irradiation target and being placed on an extension of said radiation path.

7. A therapy system using an ion beam according to claim 6, further comprising a positioning information generator for generating information for positioning said couch by using said three-dimensional image information and tomographic information of said irradiation target used at a treatment plan for said irradiation target, and a couch movement controller for controlling movement of said couch by using the positioning information.

8. A therapy system using an ion beam according to claim 5, wherein said positioning information generator generates the positioning information by using said three-dimensional image information and said tomographic information as being three-dimensional used at a treatment plan.

9. A therapy system using an ion beam according to claim 2, wherein said therapy system further comprises a first annular rotational frame mounted in said rotating gantry, a second annular frame to which said beam delivery unit is fixed, said first annular frame and said second annular frame being arranged in a sandwiching relation to a movement path of said ion beam irradiating unit, and a movable floor capable of being flexural in the circumferential direction of said rotating gantry and being moved in the circumferential direction of said rotating gantry with rotation of said ion beam irradiating unit while being guided by annular guides provided on said first and second annular frames, wherein said ion beam irradiating unit is inserted in a space defined by said movable floor surrounding the space, and said plurality of X-ray detectors detect the X-ray emitted from said X-ray generator in the space.

10. A therapy system using an ion beam according to claim 1, further comprising a detector moving device for moving said plurality of X-ray detectors to a position where the X-ray emitted from said X-ray generator are incident upon said plurality of X-ray detectors.

12. A therapy system according to claim 1, further comprising an angle sensor for detecting the rotational angle of said rotating gantry,

and wherein said image information forming unit determines said position information of the X-ray generator and said position information of the X-ray detectors based on the rotating angle detected by said angle sensor.

13. A therapy system according to claim 5, wherein said positioning information generator uses two-dimensional image information formed based on said three-dimensional image information upon generating said positioning information.

15. A therapy system using an ion beam according to claim 1, further comprising:

a positioning information generator for, when an axis extending horizontally is referred to as X direction axis, an axis extending vertically is referred to as Z direction axis and axis perpendicular to both of the X direction axis and Y direction axis and extending in the direction of the rotation axis of said rotating gantry, forming a first reference image information as two-dimensional image information in the X-Y plane defined by said X and Y direction axes and including an isocenter on the rotation axis of said rotating gantry and a second reference image information as two-dimensional image information in the X-Z plane defined by said X and Z direction axes and including said isocenter by using three-dimensional image information of said irradiation target used at a treatment plan for said irradiation target, forming a first current image information as two-dimensional image information in the X-Y plane the same as said first reference image information is formed and a second current image information as two-dimensional image information in the X-Z plane the same as said second reference image information is formed, by using said three-dimensional image information of said irradiation target formed by said image information forming unit, and then forming first information for positioning said couch in said X-Y plane by using said first reference image information and said first current image information and second information for positioning said couch in said X-Z plane by using said second reference image information and said second current image information; and

a couch movement controller for controlling movement of said couch by using said first and second positioning information.

11. A couch positioning system comprising:

a rotating gantry;

a beam delivery unit mounted to said rotating gantry and delivering an ion beam for treatment;

an X-ray generator revolving about a rotation axis of said rotating gantry with rotation of said rotating gantry and emitting X-ray at a plurality of rotation angles of said rotating gantry;

a plurality of X-ray detectors revolving about the rotation axis of said rotating gantry with rotation of said rotating gantry for detecting said X-ray emitted from said X-ray generator and outputting X-ray detection signals; and

a controller for positioning a couch based on three-dimensional image information of said irradiation target formed by using information obtained based on X-ray detection signals from said plurality of X-ray detectors obtained upon rotation of said rotating gantry, position information of said X-ray generator emitting the X-ray and position information of said plurality of X-ray detectors outputting the X-ray detection signals, and three-dimensional tomographic information of said irradiation target used at a treatment plan.

14. A couch positioning system according to claim 11, further comprising an angle sensor for detecting the rotational angle of said rotating gantry,

and wherein said position information of the X-ray generator and said position information of the X-ray detectors is information determined based on the rotational angle of the rotating gantry detected by said angle sensor.

16. A couch positioning system according to claim 11, wherein when an axis extending horizontally is referred to as X direction axis, an axis extending vertically is referred to as Z direction axis and axis perpendicular to both of the X direction axis and Y direction axis and extending in the direction of the rotation axis of said rotating gantry, said controller forms a first reference image information as two-dimensional image information in the X-Y plane defined by said X and Y direction axes and including an isocenter on the rotation axis of said rotating gantry and a second reference image information as two-dimensional image information in the X-Z plane defined by said X and Z direction axes and including said isocenter by using three-dimensional tomographic information of said irradiation target used at a treatment plan for said irradiation target, forms a first current image information as two-dimensional image information in the X-Y plane the same as said first reference image information is formed and a second current image information as two-dimensional image information in the X-Z plane the same as said second reference image information is formed, by using said three-dimensional image information of said irradiation target formed based on said X-ray detection signals and the position information of said X-ray generator and X-ray detectors, and then forms first information for positioning said couch in said X-Y plane by using said first reference image information and said first current image information and second information for positioning said couch in said X-Z plane by using said second reference image information and said second current image information.