A single photon emission computer tomograph for breast cancer imaging

We have developed a tomograph for single photon emission imaging (SPECT) of the breast for the detection of small size tumors. The SPECT is mounted on a ring that is rotating around the breast with the patient in prone position. The breast will be imaged by two opposing detector heads of approximately 5×15cm2 each, with a field of view about 13cm wide. Each head is made up of one pixilated NaI crystal matrix coupled to three Hamamatsu H8500 PMTs. A “general purpose” lead collimator is positioned in front of the crystal. Detailed simulations have been made for the optimization and the evaluation of the detector performances. Monte Carlo results indicate that tumors of 8mm diameter are detectable with a tumor/background uptake ratio of 5:1. The experimental characterization of the detector head is presented. The rotating ring is now being assembled.