Mainz 2012 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 17: Anwendungen kernphysikalischer Methoden
HK 17.9: Talk
Tuesday, March 20, 2012, 18:45–19:00, RW 3
Submillimeter medical imaging in emission tomography* — •C. Lang1, D. Habs1,2, P.G. Thirolf1, and A. Zoglauer3 — 1LMU, München — 2MPQ, Garching — 3SSL, Berkeley
We present a nuclear medical imaging technique, capable to reach submillimeter spatial resolution in 3 dimensions with a short exposure time and a low radioactive dose compared to conventional PET. This ’γ-PET’ technique takes advantage of specific e+ sources which simultaneously with the β+ decay emit an additional photon. Exploiting the triple coincidence between the positron annihilation and the additional emitted γ, it is possible to separate the reconstructed ’true’ events from background. Thus the spatial uncertainty introduced by the motion of the e+ or by Compton scattering within the patient can be strongly reduced in the direction normal to the annihilation. MC-simulations and image reconstruction studies have been performed using the library MEGAlib, which we modified to realize an event reconstruction using the β+ γ coincidences. The simulated geometry consists of 4 LaBr3 scintillator crystals (5× 5× 3 cm3) read out by a 2D-segmented photomultiplier (64 pixels, each 6× 6 mm2) and 4 double-sided silicon strip detectors (each with 2× 128 strips, active area of 5× 5 cm2, thickness 0.5 mm), positioned around an H2O sphere of 6 cm diameter. Inside are two 22Na point-like test sources, placed at a distance of 0.4 mm. The resolution results in 0.2 mm (FWHM) in each direction, surpassing the performance of conventional PET by about an order of magnitude.
*Supported by the DFG Cluster of Excellence "Munich-Centre for Advanced Photonics" (MAP).