Computed tomography apparatus and method for operating same

• US 6,600,803 B2
• Filed: 10/01/2001
• Issued: 07/29/2003
• Est. Priority Date: 09/29/2000
• Status: Expired due to Fees

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Seifert, Heinrich, Bruder, Herbert, Siebold, Horst
• Primary Examiner(s): Dunn, Drew A.
• Assistant Examiner(s): Ho, Allen C.
• Application Number:
  US09/968,152
• Publication Number:
  US 20020071518A1
• Time in Patent Office: 666 Days
• Field of Search: 378/4, 378/19, 378/901, 382/131
• US Class Current: 378/19
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4233 using matrix detectors

Abstract

In a computed tomography system equipped with a data-acquisition system and a method for operating such a computed tomography system, the computed tomography system has a radiation detector with at least one linear detector array composed of a row several detector elements aligned adjacent to one another. The data-acquisition system reads out the detector elements and forms difference signals from signals read out from pairs of adjacent detector elements.

Claims

1. A computed tomography apparatus comprising:

a radiation source which emits an x-ray beam, and a radiation detector on which said X-ray beam is incident after penetrating a subject;

said radiation detector comprising at least one linear detector array comprising a row of a plurality of detector elements aligned adjacent to one another, the respective detector elements emitting electrical signals dependent on X-rays incident thereon; and

a data acquisition system connected to said radiation detector for reading out the respective signals from pairs of adjacent detector elements in said row and forming respective difference signals from said pairs of signals, and further processing said difference signals.

2. A computed tomography apparatus as claimed in claim 1 wherein the respective signals emitted by said detector elements are analog signals, and wherein said data acquisition system comprises at least one analog-to-digital converter which digitizes said analog signals.

3. A computed tomography apparatus as claimed in claim 1 wherein said difference signals, as a result of the respective signals emitted by said detector elements being digitized, also are digital, and wherein said digital difference signals each have a data length of one byte.

4. A computed tomography apparatus as claimed in claim 1 wherein the respective signals emitted by said detector elements are analog signals, and wherein said data acquisition system comprises at least one analog-to-digital converter for digitizing said difference signals.

5. A computed tomography apparatus as claimed in claim 4 wherein said digitized difference signals each have a data length of one byte.

6. A computed tomography apparatus as claimed in claim 1 wherein said radiation detector comprises a plurality of detector modules, each of said detector modules comprising a plurality of linear detector arrays, each comprising a plurality of said detector elements aligned adjacent to each other, and wherein said data acquisition system comprises a plurality of analog-to-digital converters respectively connected to said plurality of detector modules for digitizing the respective signals emitted by said detector elements.

7. A method for acquiring signals from a computed tomography apparatus comprising the steps of:

conducting a scan of a subject in a plurality of scanning steps by irradiating said subject with X-rays from an X-ray source and detecting X-rays after penetrating said subject with a radiation detector having at least one detector module comprising at least one linear detector array with a plurality of detector elements aligned adjacent to one another;

reading out respective signals from each of said detector elements of a detector module at each scanning step with a data acquisition system; and

forming signals S*_j,m,k in said data acquisition system from signals read from detector elements of a j^th detector module, wherein S*_j,m,1=S_j,m,1 for k=1 and S*_j,m,k=S_j,m,k−

S<sub>j,m,k−

1</sub> for 1<

k≦

K, wherein S_j,m,k is the signal read out from the k^th detector element of m^th linear detector array of the j^th detector module, and wherein K is the number of detector elements in said m^th linear detector array.

8. A method as claimed in claim 7 wherein said signals S_j,m,k are analog signals, and comprising the additional step of digitizing said signals S_j,m,k and further processing said signals S_j,m,k in digital form.

9. A method as claimed in claim 8 wherein said signals S*_j,m,k, as a result of said signals S_j,m,k being digitized, also are digital, and wherein said signals S*_j,m,k each have a data length of 1 byte.

10. A method as claimed in claim 7 wherein said signals S*_j,m,k are analog signals, and comprising the additional step of digitizing said signals S*_j,m,k, and further processing said signals S*_j,m,k in digital form.

11. A method as claimed in claim 10 wherein said digital signals S*_j,m,k each have a data length of 1 byte.

12. A method for acquiring signals from a computed tomography apparatus comprising the steps of:

conducting a scan of a subject in a plurality of scanning steps by irradiating said subject with X-rays from an X-ray source and detecting X-rays after penetrating said subject with a radiation detector having at least one detector module comprising at least one detector column with a plurality of detector elements aligned adjacent to one another;

reading out respective signals from each of said detector elements of a detector module at each scanning step with a data acquisition system; and

forming signals S*_j,m,k in said data acquisition system from signals read from detector elements of a j^th detector module, wherein S*_j,1,k=S_j,1,k for m=1 and S*_j,m,k=S_j,m,k−

S<sub>j,m−

1k</sub> for 1<

m≦

M, wherein S_j,m,k is the signal read out from the m^th detector element of k^th detector column of the j^th detector module, and wherein M is the number of detector elements in said k^th detector column.

13. A method as claimed in claim 12 wherein said signals S_j,m,k are analog signals, and comprising the additional step of digitizing said signals S_j,m,k and further processing said signals S_j,m,k in digital form.

14. A method as claimed in claim 13 wherein said signals S*_j,m,k, as a result of said signals S_j,m,k being digitized, also are digital, and wherein said signals S*_j,m,k each have a data length of 1 byte.

15. A method as claimed in claim 12 wherein said signals S*_j,m,k are analog signals, and comprising the additional step of digitizing said signals S*_j,m,k, and further processing said signals S*_j,m,k in digital form.

16. A method as claimed in claim 15 wherein said digital signals S*_j,m,k each have a data length of 1 byte.