A new algorithm for the attenuation correction in SPECT

The proposed method is based on the reconstruction of the activity distribution c(ij) on a section S, with ij=1 to 64, assuming that the attenuation coefficients /spl mu/(ij) on the section are known. This method, for every section, stores in a matrix 64/spl times/64 elements N projections of the section acquired at angles k/spl phi//sub 0/(k-1 to N, /spl phi//sub 0/=360/sup c//N). The simplified hypothesis that along k the radioactive concentration c changes in a linear way is made. Using a best fit method the values of radioactive concentration along this direction are calculated and the correct projection is obtained. The algorithm of filtered back-projection is used to reconstruct the distribution c(ij) on the section. The method was tested using theoretical phantoms of different shapes, locations and radioactive types. The method needs very short times because the attenuation correction and the reconstruction procedure are performed at the same time.