Jun 13 – 15, 2012
LAL Orsay
Europe/Paris timezone

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

Jun 14, 2012, 10:05 AM
Amphithéâtre Pierre Lehmann (LAL Orsay)

Amphithéâtre Pierre Lehmann

LAL Orsay

Centre Scientifique d'Orsay - Bat 200 91898 Orsay cedex FRANCE
Oral presentation SiPM applications


Matthieu Heller (CERN)


The AX-PET (AXial Positron Emission Tomography) experiment proposes a novel geometrical approach for a PET scanner, in which long LYSO scintillator crystals are placed axially in the tomograph. Arrays of WLS strips, placed behind each layer of crystals, provide the measurement of the axial coordinate. Both the crystals and the WLS strips are individually read out by G-APDs (Geiger-mode Avalanche Photo Diodes). Such a matrix of LYSO crystals and WLS strips allows for a 3D localization of the photons interactions (both photoelectric absorption and Compton scattering), with good spatial resolution and without compromising on the sensitivity of the detector. Two AX-PET modules have been built at CERN and fully characterized with point-like Na-22 sources, demonstrating competitive performance in terms of spatial and energy resolutions. Operated in coincidence, the two modules represent the demonstrator for a PET prototype, which has been successfully used for the reconstruction of images of several phantoms filled with F-18 in aqueous solution. The AX-PET detector concept, its performance, the reconstructed images of different phantoms will be described briefly. The emphasis will be put on the actual limitations of the current demonstrator set-up and how part of these limitations could be overcome by the use of the novel digital Silicon Photomultiplier (dSiPM) technology from Philips. With their highly integrated read-out electronics and excellent intrinsic time resolution, dSiPMs may allow for compact detector modules with Time of Flight capability (TOF-PET). We will present a number of performance measurements in view of their application in the AX-PET concept.

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