X-ray apparatus

• US 5,265,144 A
• Filed: 01/15/1992
• Issued: 11/23/1993
• Est. Priority Date: 01/19/1991
• Status: Expired due to Term

• Current Assignee: Morpho Detection (Safran SA)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Harding, Geoffrey, Martens, Gerhard
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): CHU, KIM KWOK
• Application Number:
  US07/821,511
• Time in Patent Office: 678 Days
• Field of Search: 378/86, 378/87, 378/70, 378/147, 378/62, 378/88, 378/149, 250/363.08, 250/363.1
• US Class Current: 378/86
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4241 using energy resolving detectors, e.g. photon counting
• CPC Class Codes: A61B 6/483 involving scattered radiation
• CPC Class Codes: G01N 23/201 by measuring small-angle scattering
• CPC Class Codes: G21K 1/025 using multiple collimators, e.g. Bucky screens; other devices for eliminating undesired or dispersed radiation

Abstract

An X-ray apparatus comprises a polychromatic X-ray source for generating a primary beam of small cross-section, an energy-sensitive detector arrangement for detecting the scattered radiation produced by elastic scattering processes in the primary beam, which detector arrangement comprises a plurality of detector elements which are arranged on rings concentric with the primary beam, and a collimator arrangement which is arranged between the X-ray source and the detector arrangement and which encloses the primary beam. In order to enable accurate determination of the pulse transfer spectrum while using a low dose, the collimator arrangement is constructed so that the scattered radiation from the same section of the primary beam is incident on a plurality of detector elements.

Claims

1. An X-ray apparatus, comprising a polychromatic X-ray source for generating a primary beam of limited cross-section along a primary beam path, an energy-sensitive detector means comprising a central detector element situated in the primary beam path and a sequence of detector elements arranged on rings of successively increasing diameter surrounding said primary beam for detecting scattered radiation generated by elastic scattering processes in the primary beam path, a collimator means between the X-ray source and the sequence of detector elements and which encloses the primary beam, said collimator means being constructed in a manner that scattered radiation from said elastic scattering processes occurring within a given portion of the primary beam path is incident on a plurality of said sequence of detector elements, and further comprising means for determining a pulse transfer spectrum from energy spectra of X-ray quanta incident on the respective detector elements of said sequence which are normalized to an energy spectrum of X-ray quanta incident on the central detector element.

2. An X-ray apparatus as claimed in claim 1, further comprising means for normalizing the energy spectra of X-ray quanta incident on the respective detector elements of said sequence to the energy spectrum of said X-ray quanta incident on the central detector element.

3. An X-ray apparatus as claimed in claim 2 wherein the collimator means comprises a plurality of collimator laminations which are concentric with the primary beam and which are shaped as a truncated cone surface, having prolongations intersecting one another substantially in a same point located in said given portion of the primary beam path.

4. An X-ray apparatus as claimed in claim 1 wherein the collimator means comprises a plurality of collimator laminations which are concentric with the primary beam and which are shaped as a truncated cone surface, having prolongations intersecting one another substantially in a same point located in said given portion of the primary beam path.