X-ray generator with a limiting device

• US 6,549,609 B1
• Filed: 09/26/2000
• Issued: 04/15/2003
• Est. Priority Date: 10/13/1999
• Status: Expired due to Fees

• Current Assignee: Shimadzu Corporation
• Original Assignee: Shimadzu Corporation
• Inventors: Iinuma, Masao, Takemoto, Hajime
• Primary Examiner(s): Dunn, Drew A.
• Assistant Examiner(s): Barber, Therese
• Application Number:
  US09/669,666
• Time in Patent Office: 931 Days
• Field of Search: 378/98.7, 378/98.8, 378/145, 378/150, 378/151, 378/160, 378/205, 378/98.5
• US Class Current: 378/150
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/4225 using image intensifiers
• CPC Class Codes: A61B 6/4233 using matrix detectors
• CPC Class Codes: A61B 6/542 involving control of exposure
• CPC Class Codes: A61B 6/544 dependent on patient size

Abstract

An X-ray tube (3) is rotated about its focal point along a plane perpendicular to a body axis of a patient by an X-ray tube rotation driver and thus the X-ray irradiation field moves. When the side of the X-ray irradiation field reaches an edge detector (6a) in the edge part of the flat panel detector, the edge detector detects X-ray and provides a signal to a controller. The controller controls the X-ray limiting device (4a) to move shield blades thereof to limit the range of the X-ray irradiation field. The above structure makes it possible to move the center of the X-ray irradiation field without moving the patient and also to prevent the X-ray irradiation field from going outside of the flat panel detector.

Claims

1. An X-ray apparatus, comprising:

an X-ray tube;

a solid state flat detector opposing said X-ray tube across a patient being examined, the patient defining a body axis;

an X-ray limiting device for limiting X-rays from said X-ray tube;

a driver for rotating said X-ray tube and said X-ray limiting device about a stationary axis disposed above the patient and extending parallel to the body axis, wherein the driver rotates said X-ray tube and said X-ray limiting device in an arc defining a plane oriented perpendicularly to the body axis;

an edge detector for detecting x-rays irradiated onto an edge part of said solid state flat detector;

a controller for receiving a signal from said edge detector and controlling, with said signal, said X-ray limiting device so that X-rays do not go outside of said solid state flat detector.

2. An X-ray apparatus according to the claim 1, wherein said edge detector comprises X-ray semiconductor elements in edge parts of said solid state flat detector.

3. An X-ray apparatus according to the claim 1, wherein said edge detector comprises a separate X-ray detector from said solid state flat detector.

4. An X-ray apparatus according to the claim 1, further comprising:

a handle for providing signals depending on an amount of manipulation set by an operator;

an X-ray tube rotation controller for rotating said X-ray tube depending on said signals.

5. An X-ray apparatus according to the claim 1, wherein said X-ray limiting device having two shield blades which limit X-rays in a direction which is perpendicular to a body axis of said person.

6. An X-ray apparatus according to the claim 5, further comprising:

a handle for providing signals depending on an amount of manipulation set by an operator;

a shield blade movement controller for moving said two shield blades in opposite directions from each other, depending on said signals.

7. An X-ray apparatus according to the claim 5, further comprising:

two handles for providing signals depending on amounts of manipulation set by an operator;

a shield blade movement controller for moving said two shield blades independently, depending on said signals.

8. An X-ray apparatus according to the claim 1, further comprising:

a detector for detecting a rotation angle of said X-ray tube, and providing a signal related to said rotation angle;

a controller for receiving said signal from said detector and controlling said X-ray limiting device so that X-rays from said X-ray tube do not go outside of said solid state flat detector.

9. An X-ray apparatus according to claim 1, wherein the X-ray tube and the X-ray limiting device are connected to each other.

10. An X-ray apparatus according to claim 9, wherein the X-ray tube and the X-ray limiting device are simultaneously rotated by the driver about the arc.

11. An X-ray apparatus, comprising:

an X-ray tube;

a solid state flat detector opposing said X-ray tube across a patient being examined, the patient defining a body axis;

an X-ray limiting device for limiting X-rays from said X-ray tube;

a driver for rotating said X-ray tube and said X-ray limiting device about a stationary axis disposed above the patient and extending parallel to the body axis in an arc defining a plane oriented perpendicularly to the body axis;

a detector for detecting a rotation angle of said X-ray tube, and providing a signal related to said rotation angle; and

a controller for receiving said signal from said detector and controlling said X-ray limiting device so that X-rays from said X-ray tube do not go outside of said solid state flat detector,

wherein said controller calculates a permissible aperture size defined as a distance between a center of an X-ray irradiation field and an edge of said solid state flat detector, and controlling said X-ray limiting device so that an outer half of X-rays from said X-ray tube is limited to within said permissible aperture size.

12. An X-ray apparatus according to the claim 11, wherein said X-ray limiting device has two shield blades which move along a plane which is perpendicular to a body axis, said blades limiting the X-rays.

13. An X-ray apparatus according to the claim 12, further comprising:

a handle for providing signals depending on an amount of manipulation set by an operator;

a shield blade movement controller for moving the two shield blades in opposite directions from each other, depending on said signals.

14. An X-ray apparatus according to the claim 11, further comprising:

two handles for providing signals depending on amounts of manipulation set by an operator;

a shield blade movement controller for moving two shield blades independently, depending on said signals.

15. An X-ray apparatus, comprising:

an X-ray tube;

a solid state flat detector opposing said X-ray tube across a patient being examined, the patient defining a body axis;

an X-ray limiting device for limiting X-rays from said X-ray tube;

a driver for rotating said X-ray tube and said X-ray limiting device about a stationary axis disposed above the patient and extending parallel to the body axis in an arc defining a plane oriented perpendicularly to the body axis;

a detector for detecting a rotation angle of said X-ray tube, and providing a signal related to said rotation angle; and

a controller for receiving said signal from said detector and controlling said X-ray limiting device so that X-rays from said X-ray tube do not go outside of said solid state flat detector,

wherein said controller calculates a permissible aperture size based on an angle between an edge of said solid state flat plate detector and a center of an X-ray irradiation field, and controlling said X-ray limiting device so that an outer half of X-rays from said X-ray tube is limited to within said permissible aperture size.