Title :
Development of a four-layer DOI detector composed of Zr-doped GSO scintillators and a high sensitive multi-anode PMT
Author :
Nitta, M. ; Hirano, Yoshikuni ; Inadama, Naoko ; Nishikido, Fumihiko ; Yoshida, Erika ; Tashima, Hideaki ; Kawai, Hiroyuki ; Ito, H. ; Yamaya, Taiga
Author_Institution :
Chiba Univ., Chiba, Japan
fDate :
Oct. 27 2012-Nov. 3 2012
Abstract :
We are developing an open-type PET scanner "Open PET" dedicated to in-beam imaging for carbon ion therapy. In this paper, we developed a 4-layered depth of interaction (DOI) detector suitable for the OpenPET. In a small OpenPET prototype we have previously developed, LGSO scintillator was used in expectation of its large scintillation photon yield and high stopping power. However, in in-beam PET use, we found that self luminescence of Lu-176 radioisotope degraded signal-to-noise ratio because activity generated through auto-activation was very limited. Therefore, in this study, we selected Zr-doped GSO (GSOZ) scintillation crystals as a Lu-free scintillator. On the other hand, we should pay attention to decreased light yield of GSOZ compared with LGSO. To compensate this, we employed a MA-PMT having a super bialkali (SBA) photo cathode, which had about 1.3 times higher quantum efficiency than a conventional bialkali (BA) photo cathode. The effect of using the SBA-PMT was evaluated in terms of energy resolution and crystal identification performance. The results showed that the energy resolution of the detector with the SBA-PMT was improved by about 10% as compared to the detector with the BA. The crystal identification performance, which was degraded at the periphery for the BA-PMT such as a few crystal responses overlapped each other, was improved by the use of the SBA-PMT.
Keywords :
luminescence; photocathodes; positron emission tomography; radioisotopes; scintillation; solid scintillation detectors; 4-layered depth of interaction detector; LGSO scintillator; Lu-176 radioisotope; Lu-free scintillator; MA-PMT; OpenPET prototype; SBA-PMT; Zr-doped GSO scintillation crystals; Zr-doped GSO scintillators; auto-activation; carbon ion therapy; crystal identification performance; crystal responses; energy resolution; four-layer DOl detector; high sensitive multianode PMT; high stopping power; in-beam PET; in-beam imaging; large scintillation photon yield; light yield; open-type PET scanner OpenPET; quantum efficiency; self-luminescence; signal-to-noise ratio; super bialkali photocathode;
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC), 2012 IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
978-1-4673-2028-3
DOI :
10.1109/NSSMIC.2012.6551747