The AX-PET experiment: A demonstrator for an axial Positron Emission Tomograph

AX-PET stands for a new geometrical concept for a high resolution and high sensitivity PET scanner, based on an axial arrangement of long scintillating crystals in the tomograph, for a parallax free PET detector. Two identical AX-PET modules - consisting of matrices of LYSO crystals interleaved with WLS strips - have been built. They form the AX-PET Demonstrator, which has been extensively characterized and successfully used for the reconstruction of images of several phantoms. In this paper we report on the current status of the project, with emphasis on the most relevant results achieved both in terms of detector characterization and image reconstruction. We also discuss the recent preliminary results obtained with the digital SiPM from Philips (dSiPM), which are currently being tested as a possible alternative photodetector for AX-PET. With their very good intrinsic time resolution, dSiPM could add Time of Flight capability to the AX-PET concept.