Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8175151 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2014 | 7 Pages |
Abstract
A depth-of-interaction (DOI) detector is required for developing a high resolution and high sensitivity PET system. Ce-doped Gd3Al2Ga3O12 (GAGG fast: GAGG-F) is a promising scintillator for PET applications with high light output, no natural radioisotope and suitable light emission wavelength for semiconductor based photodetectors. However, no DOI detector based on pulse shape analysis with GAGG-F has been developed to date, due to the lack of appropriate scintillators of pairing. Recently a new variation of this scintillator with different Al/Ga ratios-Ce-doped Gd3Al2.6Ga2.4O12 (GAGG slow: GAGG-S), which has slower decay time was developed. The combination of GAGG-F and GAGG-S may allow us to realize high resolution DOI detectors based on pulse shape analysis. We developed and tested two GAGG phoswich DOI block detectors comprised of pixelated GAGG-F and GAGG-S scintillation crystals. One phoswich block detector comprised of 2Ã2Ã5 mm pixel that were assembled into a 5Ã5 matrix. The DOI block was optically coupled to a silicon photomultiplier (Si-PM) array (Hamamatsu MPPC S11064-050P) with a 2-mm thick light guide. The other phoswich block detector comprised of 0.5Ã0.5Ã5 mm (GAGG-F) and 0.5Ã0.5Ã6 mm3 (GAGG-S) pixels that were assembled into a 20Ã20 matrix. The DOI block was also optically coupled to the same Si-PM array with a 2-mm thick light guide. In the block detector of 2-mm crystal pixels (5Ã5 matrix), the 2-dimensional histogram revealed excellent separation with an average energy resolution of 14.1% for 662-keV gamma photons. The pulse shape spectrum displayed good separation with a peak-to-valley ratio of 8.7. In the block detector that used 0.5-mm crystal pixels (20Ã20 matrix), the 2-dimensional histogram also showed good separation with energy resolution of 27.5% for the 662-keV gamma photons. The pulse shape spectrum displayed good separation with a peak-to-valley ratio of 6.5. These results indicate that phoswich DOI detectors with the two types of GAGGs are promising for developing a high resolution PET system.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
Seiichi Yamamoto, Takahiro Kobayashi, Jung Yeol Yeom, Yuki Morishita, Hiroki Sato, Takanori Endo, Yoshiyuki Usuki, Kei Kamada, Akira Yoshikawa,