Title :
An ECAT Reconstruction Method Which Corrects for Attenuation and Detector Response
Author_Institution :
Institute of Nuclear Medicine University Hospital Utrecht Catharijnesingel 101 3511 GV Utrecht, The Netherlands
Abstract :
Measured projection values of activity distributions in tissue are degraded by the detector aperture function and the exponential attenuation along the path to the object boundary. The aperture function varies with the distance to the detector and turns the integration path into a "weighted cone" shape. Fortunately, summation of opposite views shows a nearly uniform response. Adding opposite projections reduces the problem to a deconvolution problem. Division of the projection values by the total attenuation along the path from the object boundary to the rotated axis yields an integral equation which is independent of the boundary. An additional assumption of constant attenuation in a circular activity region followed by Fourier series expansion of period 2¿ gives a set of solvable Volterra equations.
Keywords :
Apertures; Attenuation measurement; Deconvolution; Degradation; Detectors; Fourier series; Integral equations; Object detection; Reconstruction algorithms; Shape;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.1983.4332345