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Dual energy approach by spatially different x-ray spectra Disclosure Number: IPCOM000018486D
Original Publication Date: 2002-Sep-01
Included in the Prior Art Database: 2003-Jul-23
Document File: 2 page(s) / 151K

Publishing Venue



Idea: Dr. Bernhard Sandkamp, Forchheim; Mathias Hoernig, Forchheim; Dr. Burkhard Groh, Forchheim; Dr. Volker Heer, Forchheim

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Dual energy approach by spatiallydifferent x-ray spectra

Idea: Dr. Bernhard Sandkamp, Forchheim;Mathias Hoernig, Forchheim;Dr. Burkhard Groh, Forchheim;Dr. Volker Heer, Forchheim

Conventional x-ray systems consist of x-ray source,collimators and  the  x-ray  detector:  The  object  ofinterest  is  interposed  in  the  x-ray beam betweensource and detector. Dual energy is a well knowntechnique to enhance the  contrast  of  the  object  ofinterest. This is  typically  done  by  exposing  twoimages with different x-ray spectra. Processing thoseimages  allows  to  enhance  either bone or tissuecontrast.

With the current technology it is necessary to exposetwo  images.  Therefore  a  certain  time  interval bet-ween the two exposures is unavoidable, resulting inpossible artefacts due to motion of the patient.

The  proposed  solution  consists  of  a  system usingspatially different x-ray spectra.

For instance in  a  pixelized  detector  without  anyobject in the x-ray beam the pixel P(i,j) is exposedwith the same beam quality BQa as the pixel P(i, j+1)and P(i, j+3) are exposed with the same beam qualityBQb etc. Therefore one can consider the single expo-sure as two different images, one exposed with beamquality BQa and  the  other  one  with  beam  qualityBQb. In this  example  the  odd  lines  represent  oneimage and the even lines the other one. The missingpixels in the  two  images  could  be  interpolated  toobtain two images having the same resolution and nospatial shift between them. Now, the images can beprocessed as two separate images exposed with twodifferent x-ray spectra and an ordinary dual energyapproach is possible.

Some examples:

A) A mask consisting of a support with a structure offiltering material (for instance copper) on the top isbrought in  direct  contact  with  the  detector.  Thisinfluences spatially the spectrum the detector "sees"(see example A).

B) A mask consisting of a single material but withlocally  different  thicknes...