Spatial resolution and depth-of-interaction studies with a PET detector module composed of LSO and an APD array

Detailed results are given for the study of the spatial resolution obtained with different configurations of lutetium oxyorthosilicate (LSO) scintillation crystals read out by a Hamamatsu 2 × 8 avalanche photodiode (APD) array. Block detectors as well as small-sized individual LSO crystals have been coupled to the APD matrix. Both one-to-one coupling and light-sharing schemes were investigated. The spatial resolution is derived for each configuration. Two different configurations with two layers of LSO crystals shifted by half a crystal size with respect to each other are used for investigations on the depth-of-interaction information. Prior to the spatial resolution measurements, a comparison of the light output for various crystal surface treatments and different optical coupling materials has been made.