A study of the possibility of using multi-slice PET systems for 3D imaging

Two PET (positron emission tomography) system configurations have been studied by Monte Carlo simulations, one with and one without interplane septa. The basic tomograph configuration studied is a 50-cm-diameter brain system, using 2048 6-mm-wide and 12-mm-tall detectors. The detectors are arranged in eight rings with 256 detectors in each ring. It is shown that with the removal of the interplane septa and using all 64 possible ring combinations, the efficiency can be increased by a factor of about 6. This number is an average over the whole sensitive volume. In the central regions the increase can be as much as a factor of 8. The removal of the septa also increases the number of detected scattered events which have to be corrected for, for example, by a deconvolution algorithm. The accidental coincidence rate will increase by a factor of 17, limiting this mode of operation to studies with low-activity administrations less than 20 mCi. However, even for such a low administration of activity, the efficiency gain of true unscattered events with the removal of the septa is still higher than in the case where septa are used with a higher dose administration