X-Ray transmission scanning system and method and electron beam X-ray scan tube for use therewith

• US 4,352,021 A
• Filed: 01/07/1980
• Issued: 09/28/1982
• Est. Priority Date: 01/07/1980
• Status: Expired due to Term

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Boyd, Douglas P., Sparks, Robert A., Quinn, James R., Herrmannsfeldt, William B.
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Grigsby, T. N.
• Application Number:
  US06/109,877
• Time in Patent Office: 995 Days
• Field of Search: 313/56, 250/445 T, 250/416 TV
• US Class Current: 378/12
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4028 resulting in acquisition of views from substantially different positions, e.g. EBCT
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: A61B 6/4488 Means for cooling A61B6/045 takes precedence
• CPC Class Codes: A61B 6/507 for determination of haemodynamic parameters, e.g. perfusion CT
• CPC Class Codes: G06T 1/0014 Image feed-back for automatic industrial control, e.g. robot with camera robots B25J19/023
• CPC Class Codes: H01J 35/00 X-ray tubes
• CPC Class Codes: H05G 1/70 Circuit arrangements for X-ray tubes with more than one anode; Circuit arrangements for apparatus comprising more than one X ray tube or more than one cathode H05G1/58 takes precedence

Abstract

A high speed multiple section, computed-tomographic x-ray scanner is provided. The scanner utilizes a multiple-anode, scanning electron beam x-ray source to provide high speed scanning of sections of the body. No mechanical motion is involved.

Claims

1. In an x-ray transmission scanning system an electron beam scan tube for providing a plurality of adjacent movable x-ray sources comprising:

an evacuated envelope having a longitudinal axis;

an electron gun disposed axially at one end of the envelope projecting an electron beam along said axis;

a focus coil spaced from said gun to receive and focus said beam;

a plurality of adjacent longitudinally spaced curvilinear elongated targets disposed at the other end of said envelope to receive the electron beam and generate x-rays in response thereto;

means for moving said focused electron beam along said targets and from one target to another; and

a source collimator having an elongated slot disposed adjacent to each of said elongated targets to intercept said x-rays and provide an x-ray beam which fans outwardly from the received electron beam to form a fan shaped beam which rotates as the electron beam is moved along the corresponding target whereby to scan a plurality of adjacent longitudinally spaced sections at least one for for each of said targets.

2. An x-ray transmission scanning system as in claim 1 wherein said target and collimator slots lie on circles having their centers on said longitudinal axis.

3. An apparatus for obtaining an x-ray absorption distribution of an object comprising:

an evacuated elongated envelope having a longitudinal axis;

an electron gun disposed axially at one end of said envelope and projecting an electron beam along said axis;

a focus coil spaced from said gun to receive and focus said beam;

a plurality of adjacent longitudinally spaced curvilinear elongated targets disposed at the other end of said envelope to receive said electron beam and generate x-rays in response thereto;

means for moving said focused beam and direct it to a selected one of said targets and scan the beam along said target;

a source colliminator having an elongated slot adjacent to each of said elongated targets to intercept said x-rays and form an x-ray beam which fans outwardly from the received electron beam to form a fan shaped beam which rotates as the electron beam is moved along the corresponding target whereby to scan a plurality of adjacent longitudinally spaced sections, at least one for each target;

a plurality of detectors mounted opposite the elongated targets, said detectors arranged to form an elongated array, and

detector collimators serving to direct the beam onto selected ones of said detectors for each target.

4. In an x-ray transmission scanning system an electron beam scan tube for providing a plurality of adjacent movable x-ray sources comprising:

an evacuated envelope having a longitudinal axis, said envelope including a cylindrical end portion and a semi-circular conical portion;

an electron gun disposed axially at the cylindrical end and projecting an electron beam;

a focus coil spaced from the electron gun disposed at the cylindrical portion to receive and focus said beam;

bending coils spaced from said electron gun at the cylindrical portion adapted to receive said beam and direct it into said conical portion and scan the beam along selected target rings along a path which lies on a line;

a plurality of adjacent target rings disposed at the end of said conical section to receive the electron beam and generate x-rays in response thereto; and

a source collimator disposed adjacent each of said target rings to intercept said x-rays and provide a fan-shaped x-ray beam which rotates as the electron beam is moved along the corresponding target ring whereby to scan a plurality of adjacent sections one for each of said target rings.

5. An apparatus for obtaining an x-ray absorption distribution of an object comprising:

an evacuated envelope having a longitudinal axis, said envelope including a cylindrical end portion and a conical semi-circular end portion;

an electron gun disposed axially at the cylindrical end and projecting an electron beam;

a focus coil disposed at the cylindrical portion to receive and focus said beam;

bending coils following the focusing coil adapted to receive said beam and direct it into the conical end section and scan the beam along the segment of a circle;

a plurality of adjacent target rings disposed at the end of said conical section to receive said electron beam and generate x-rays in response thereto;

a source collimator adjacent each of said target rings to intercept said x-ray and form a fan-shaped x-ray beam which rotates as the electron beam is moved along the corresponding target ring whereby to form a plurality of fan-shaped x-ray beams to scan a plurality of adjacent sections, at least one for each target ring; and

a plurality of detectors mounted opposite the target ring, said detectors arranged to form an array which is a segment of a circle; and

detector collimators serving to direct the beam onto selected ones of said detectors for each target ring.

6. Apparatus as in claim 5 in which said source collimators are on a segment of a circle and in which said source and detector collimators overlap.

7. Apparatus as in claim 5 wherein said source collimators and detector collimators are arranged so that a single sweep of a target ring provides multiple scans.

8. Apparatus as in claim 5 wherein said source collimators and detector collimators are arranged so that with each sweep of the plurality of target rings there is scanned at least twice as many sections.

9. Apparatus as in claim 5 in which including means for receiving the output of said detectors, processing the output and recording the processed signals.

10. Apparatus as in claim 9 including means for receiving said processed detector signals and reconstructing an image of scanned sections.

11. Apparatus as in claim 7 including means for controlling the electron beam scan.

12. Apparatus as in claim 9 including means for displaying the reconstructed image.

13. In an x-ray transmission scanning system an electron beam scan tube for providing a plurality of adjacent movable fan-beam x-ray sources comprising

an elongated evacuated envelope having a longitudinal axis,

an electron gun disposed axially at one end of said evacuated envelope serving to project an electron beam along the axis of the evacuated envelope,

a focus coil spaced from said gun surrounding said evacuated envelope and adapted to form magnetic fields which focus the beam,

a plurality of adjacent elongated targets each lying on a circle having its center at said axis and spaced at different distances from said electron gun disposed at the other end of said envelope to receive said electron beam and generate x-rays,

means for sequentially scanning said beam along each of said elongated targets,

a source collimator lying on a circle having its center at said axis and including a slot disposed adjacent each of said targets to interrupt the x-rays from each target and pass x-rays through said slot to provide a fan shaped x-ray beam from each of said targets which x-ray beam rotates as the electron beam travels along each of the targets, said targets and collimators serving to form longitudinally spaced rotating fan beams, one for each of said targets and associated collimator slot.

14. Apparatus as in claim 13 wherein said electron deflection means comprises a beam bending coil spaced from said electron gun encircling said elongated envelope.