X-ray detecting apparatus

• US 6,445,765 B1
• Filed: 09/11/2000
• Issued: 09/03/2002
• Est. Priority Date: 09/07/2000
• Status: Expired due to Term

• Current Assignee: Smiths Heimann GmbH (Smiths Group International Holdings Ltd.)
• Original Assignee: Heimann Systems GmbH
• Inventors: Frank, Andreas, Geus, Georg, Schall, Patricia
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): Barber, Therese
• Application Number:
  US09/659,040
• Time in Patent Office: 722 Days
• Field of Search: 378/53, 378/54, 378/57, 378/88, 378/5, 378/19, 378/56, 378/98.8, 378/98.9
• US Class Current: 378/56
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/482 involving multiple energy imaging
• CPC Class Codes: G01T 1/20183 Arrangements for preventing or correcting crosstalk, e.g. optical or electrical arrangements for correcting crosstalk

Abstract

The detector materials (8, 9) of a low energy detector (5) and a high energy detector (6) are coordinated with one another to permit better separation of lower and higher energy fractions of polychromatic X-ray (X′) radiation, and consequently, create a better determination of a material of an object through which the X-rays are passed. Thus, a negligible persistence in comparison with the integration time between two detector readings is achieved.

Claims

1. A detector arrangement for detecting X-rays, comprising at least one low energy detector, and at least one high energy detector arranged downstream, where individual energy ranges of the X-ray are emitted at the same time on an object through which X-rays are passed and are attenuated in the process, wherein the low energy detector has as a detector material a scintillator comprising at least one element with an atomic number of 30 to 40, but not containing any element having a larger atomic number, said detector material being coordinated with a detector material of the high energy detector, and the latter detector material is a ceramic scintillator containing at least one element with an atomic number greater than 60.

2. The detector arrangement according to claim 1, wherein the scintillator of the low energy detector is a single crystal.

3. The detector arrangement according to claim 1, wherein the detector material of the low energy detector is zinc selenide doped with tellurium (ZnSe(Te)).

4. The detector arrangement according claim 1, wherein the detector material of the low energy detector has a thickness of 0.2 to 1.0 mm.

5. The detector arrangement according claim 1, wherein the detector material of the high energy detector is ceramic gadolinium oxysulfide Gd₂O₂S doped with at least one rare earth element selected from the group consisting of Ce, Pr and Tb.

6. The detector arrangement according to claim 5, wherein the detector material of the high energy detector has a thickness of 1.0 to 2.0 mm.

7. The detector arrangement according to claim 1, wherein the low energy detector or the high-energy detector or both are separated into individual segments by reflective layers.

8. The detector arrangement according to claim 7, wherein the reflective layers are titanium oxide.

9. The detector arrangement according to claim 7, wherein the reflective layers are aluminum oxide.

10. The detector arrangement according to claim 1, wherein the detector material corresponds to respective semiconductor photodiodes, whereby an attenuated X-ray (X′

) is converted to visible radiation and then to an electric current signal.

11. The detector arrangement according to claim 1, wherein a filter is introduced between the low energy detector and the high-energy detector.

12. The detector arrangement according to claim 11, wherein the filter comprises copper.

13. The detector arrangement according to claim 11, wherein the filter has a thickness of 0.2-1.0 mm.

14. The detector arrangement according to claim 1, wherein X-rays incident on the object have an energy range of 10 to 500 keV.

15. A detector arrangement for detecting X-rays, comprising:

at least one low energy detector; and

at least one high energy detector arranged downstream, where individual energy ranges of the X-ray are emitted at the same time on an object through which X-rays are passed and are attenuated in the process, wherein the low energy detector has as a detector material a scintillator comprising zinc selenide doped with tellurium (ZnSe(Te)), but not containing any element having a larger atomic number, said detector material being coordinated with a detector material of the high energy detector, and the latter detector material is a ceramic scintillator containing at least one element with an atomic number greater than 60.