Scanning-based detection of ionizing radiation for tomosynthesis

• US 20050008124A1
• Filed: 09/09/2003
• Published: 01/13/2005
• Est. Priority Date: 07/08/2003
• Status: Active Grant

• Current Assignee: Xcounter AB (Varex Imaging Corporation)
• Original Assignee: Xcounter AB (Varex Imaging Corporation)
• Inventors: Ullberg, Christer
• Granted Patent: US 6,940,942 B2
• Time in Patent Office: Days
• US Class Current: 378/197
• CPC Class Codes: A61B 6/025 Tomosynthesis
• CPC Class Codes: A61B 6/06 Diaphragms
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography

Abstract

An apparatus for obtaining tomosynthesis data of an object (5) comprises a radiation source (1) emitting radiation (2) centered around an axis of symmetry (3); a radiation detector (6) comprising a stack of line detectors (6a), each being directed towards the divergent radiation source to allow a ray bundle (b1, . . . , b_n, . . . , b_N) of the radiation that propagates in a respective one of a plurality of different angles (α₁, . . . , α_n, . . . , α_N) to enter the line detector; an object area arranged in the radiation path between the divergent radiation source and the radiation detector for housing the object; and a device (7) for moving the radiation source and the radiation detector relative the object essentially linearly in a direction (8) essentially orthogonal to the axis of symmetry, while each of the stack of line detectors is adapted to record a plurality of line images of radiation as transmitted through the object in a respective one of the plurality of different angles.

Claims

1. A scanning-based apparatus for obtaining tomosynthesis data of an object comprising:

a divergent radiation source emitting radiation centered around an axis of symmetry;

a radiation detector comprising a stack of line detectors, each being directed towards the divergent radiation source to allow a ray bundle of said radiation that propagates in a respective one of a plurality of different angles to enter the line detector;

an object area arranged in the radiation path between said divergent radiation source and said radiation detector for housing said object; and

a device for moving said divergent radiation source and said radiation detector relative said object essentially linearly in a direction essentially orthogonal to said axis of symmetry, while each of said line detectors is adapted to record a plurality of line images of radiation as transmitted through said object in a respective one of said plurality of different angles.

2. The apparatus of claim 1 wherein said plurality of different angles are distributed over an angular range of at least 5°

.

3. The apparatus of claim 1 wherein said plurality of different angles are distributed over an angular range of at least 10°

.

4. The apparatus of claim 1 wherein said plurality of different angles are distributed over an angular range of at least 15°

.

5. The apparatus of claim 1 wherein the number of line detectors in said stack of line detectors is at least 3.

6. The apparatus of claim 1 wherein the number of line detectors in said stack of line detectors is at least 5.

7. The apparatus of claim 1 wherein the number of line detectors in said stack of line detectors is at least 10.

8. The apparatus of claim 1 wherein said device for moving is adapted to move said divergent radiation source and said radiation detector relative said object a length which is sufficient for scanning each of said line detectors across the entire object to obtain, for each of said line detectors, a two-dimensional image of radiation as transmitted through said object in a respective one of said plurality of different angles.

9. The apparatus of claim 1 wherein

said divergent radiation source is an X-ray source;

and

said line detectors are each a gaseous-based ionization detector, wherein electrons freed as a result of ionization by a respective ray bundle are accelerated in a direction essentially perpendicular to the direction of that ray bundle.

10. The apparatus of claim 9 wherein said gaseous-based ionization detector is an electron avalanche detector.

11. The apparatus of claim 1 wherein said line detectors are each any of a diode array, a scintillator-based array, a CCD array, a TFT- or CMOS-based detector, or a liquid detector.

12. The apparatus of claim 1 comprising a collimator arranged in the radiation path between said radiation source and said object area, said collimator preventing radiation, which is not directed towards said line detectors, from impinging on said object, thereby reducing the radiation dose to said object.

13. A scanning-based method for obtaining tomosynthesis data of an object using a divergent radiation source, which emits radiation centered around an axis of symmetry;

and a radiation detector comprising a stack of line detectors, each being directed towards the divergent radiation source to allow a ray bundle of said radiation that propagates in a respective one of a plurality of different angles to enter the line detector, the scanning-based method comprising the steps of;

arranging said object in the radiation path between said divergent radiation source and said radiation detector; and

moving said divergent radiation source and said radiation detector relative said object essentially linearly in a direction essentially orthogonal to said axis of symmetry, while, by each of said line detectors, recording a plurality of line images of radiation as transmitted through said object in a respective one of said plurality of different angles.

14. The method of claim 13 wherein said divergent radiation source and said radiation detector are moved relative said object a length which is sufficient for scanning each of said line detectors across the entire object to obtain, for each of said line detectors, a two-dimensional image of radiation as transmitted through said object in a respective one of said plurality of different angles.