THREE-DIMENSIONAL RECONSTRUCTION IN NUCLEAR MEDICINE BY ITERATIVE LEAST-SQUARES AND FOURIER TRANSFORM TECHNIQUES

Quantitative three-dimensional distribution of radioisotopes in patients is determined by digital reconstruction of data from many views taken by rotating the subject at 10 deg intervals before the gamma camera. The superiority of these techniques over conventional tomography is demonstrated by comparisons between reconstruction algorithms such as back-projection, simultaneous iterative reconstruction, iterative least-squares, and back-projection of filtered projection. The filtered back-projection technique (convolution method) is superior in speed; however, for quantitative results that take into account both noise and attenuation, the iterative least-squares method gives the best approximation to the real source distributions. Resolution is 1.25 cm for detection of holes in 20-cm-diamieter objects. Mathematical basis and FOR-TRAN listings applicable to transmission and emission imaging are given, as well as results of phantom and patient studies. (60 references) (auth)