Method and apparatus for producing tomosynthesis exposures employing a reference object composed of a number of sub-objects

• US 6,005,907 A
• Filed: 05/19/1997
• Issued: 12/21/1999
• Est. Priority Date: 05/17/1996
• Status: Expired due to Fees

• Current Assignee: Sirona Dental Systems GmbH (Sirona Dental Systems Incorporated)
• Original Assignee: Sirona Dental Systems GmbH & Co. KG.
• Inventors: Ploetz, Josef
• Primary Examiner(s): Church, Craig E.
• Application Number:
  US08/859,813
• Time in Patent Office: 946 Days
• Field of Search: 378/2, 378/162
• US Class Current: 378/2
• CPC Class Codes: A61B 6/025 Tomosynthesis
• CPC Class Codes: A61B 6/584 determining position of components of the apparatus or device using images of the phantom

Abstract

In a method and an apparatus for producing a tomosynthesis exposure of an examination subject, an X-ray beam is directed at the subject from different directions and a reference object composed of at least two sub-objects is disposed in the X-ray beam together with the subject. X-rays attenuated by the reference object composed of at least two sub-objects and the examination subject are received by a radiation receiver, which generates electrical signals corresponding to X-rays incident thereon, from which a tomosynthesis image is constructed.

Claims

1. A method for producing a tomosynthesis exposure of an examination subject comprising the steps of:

directing an X-ray beam at an examination subject from an X-ray emitter from different directions with said X-ray emitter at different positions respectively defining said different directions;

forming a reference object of at least two sub-objects and placing said reference object composed of at least two sub-objects in said X-ray beam;

disposing a radiation receiver in said X-ray beam behind said subject and said reference object with no fixed spatial relation to said reference object;

receiving X-rays from said X-ray emitter, attenuated by said reference object and said subject, at said radiation receiver during a plurality of exposures, each of said exposures being made from one of said different directions, and generating electrical signals for each exposure corresponding to X-rays incident at said radiation receiver; and

from said electrical signals, identifying the position of said X-ray emitter during each of said exposures from a location of said sub-objects in each exposure, and generating a tomosynthesis image of said subject.

2. A method as claimed in claim 1 wherein the step of forming said reference object from at least two sub-objects comprises arranging at least three sub-objects relative to each other in an arrangement deviating from a straight line.

3. A method as claimed in claim 1 comprising arranging at least three sub-objects to form a geometrical body.

4. A method as claimed in claim 3 comprising the step of arranging said at least three sub-objects in a crucial shape.

5. A method as claimed in claim 2 comprising forming said reference object of at least three spherical sub-objects.

6. A method as claimed in claim 2 comprising forming said reference object of at least three disk-shaped sub-objects.

7. A method as claimed in claim 1 wherein the step of forming said reference object from at least two sub-objects comprises forming said reference object from at least two beam-shaped sub-objects.

8. A method as claimed in claim 1 wherein the step of forming said reference object from at least two sub-objects comprises forming said reference object from at least two rod-shaped sub-objects.

9. A method as claimed in claim 1 wherein the step of forming said reference object from at least two sub-objects comprises forming said reference object from at least two cylindrical sub-objects.

10. A method as claimed in claim 1 wherein the step of forming said reference object of at least two sub-objects comprises forming said reference object of at least two sub-objects having respectively different radiation absorption characteristics.

11. A method as claimed in claim 1 comprising the additional step of directly connecting said reference object to said radiation emitter with a fixed reference relationship to said radiation emitter.

12. A method as claimed in claim 1 wherein the step of forming said reference object of at least two sub-objects comprises forming said reference object by arranging said at least two sub-objects along a straight line.

13. A method as claimed in claim 12 comprising the additional step of employing two sub-objects having respectively different radiation absorption characteristics.

14. An apparatus for producing a tomosynthesis exposure of an examination subject comprising:

a radiation emitter which emits an X-ray beam successively proceeding in a plurality of different directions respectively defined by different positions of said radiation emitter;

a reference object disposed in said X-ray beam and composed of at least two sub-objects;

a radiation receiver on which said X-ray beam, attenuated by said examination subject and said reference object composed of at least two sub-objects, is incident, said radiation receiver having no fixed spatial relation to said reference object and producing electrical signals corresponding to X-rays incident thereon during a plurality of successive exposures with said radiation emitter respectively in one of said different positions in said successive exposures; and

means for identifying, from said electrical signals, a position of said radiation emitter during each of said exposures from a location of said sub-objects in each exposure and for producing a tomosynthesis image of said subject.

15. An apparatus as claimed in claim 14 further comprising means for connecting said reference object to said radiation emitter in a fixed reference relationship to said radiation emitter.

16. An apparatus as claimed in claim 14 wherein said reference object comprises at least three sub-objects oriented relative to each other in an arrangement deviating from a straight line.

17. An apparatus as claimed in claim 16 wherein said at least three sub-objects form a geometrical body.

18. An apparatus as claimed in claim 16 wherein said sub-objects are arranged in a crucial shape.

19. An apparatus as claimed in claim 16 wherein said at least three sub-objects each comprise a sphere.

20. An apparatus as claimed in claim 16 wherein each of said at least three sub-objects is disk-shaped.

21. An apparatus as claimed in claim 14 wherein said at least two sub-objects are each beam-shaped.

22. An apparatus as claimed in claim 14 wherein said at least two sub-objects are each rod-shaped.

23. An apparatus as claimed in claim 14 wherein said at least two sub-objects are each cylindrical.

24. An apparatus as claimed in claim 14 wherein each of said sub-objects has respectively different radiation absorption characteristics.

25. An apparatus as claimed in claim 14 wherein said at least two sub-objects are arranged along a straight line.

26. An apparatus as claimed in claim 25 wherein said at least two sub-objects have respectively different radiation absorption characteristics.