Dual energy approach by spatially different x-ray spectra
Original Publication Date: 2002-Sep-01
Included in the Prior Art Database: 2003-Jul-23
Idea: Dr. Bernhard Sandkamp, Forchheim; Mathias Hoernig, Forchheim; Dr. Burkhard Groh, Forchheim; Dr. Volker Heer, Forchheim
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.
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...