Investigation of the optimal detector arrangement for the helmet-chin PET – A simulation study
| Autor: | Abdella M. Ahmed, Hideaki Tashima, Eiji Yoshida, Taiga Yamaya |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
Nuclear and High Energy Physics Scanner 010308 nuclear & particles physics business.industry Detector 01 natural sciences Lyso Imaging phantom 030218 nuclear medicine & medical imaging Crystal 03 medical and health sciences 0302 clinical medicine Optics 0103 physical sciences business Instrumentation Block size Image resolution Block (data storage) |
| Zdroj: | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. 858:96-100 |
| ISSN: | 0168-9002 |
| Popis: | High sensitivity and high spatial resolution dedicated brain PET scanners are in high demand for early diagnosis of neurodegenerative diseases and studies of brain functions. To meet the demand, we have proposed the helmet-chin PET geometry which has a helmet detector and a chin detector. Our first prototype scanner used 54 4-layer depth-of-interaction (DOI) detectors. The helmet detector of the scanner had three detector rings with different radii arranged on a surface of a hemisphere (with a radius of 126.5 mm) and a top cover detector. Therefore, in this study, for our next development, we propose a spherical arrangement, in which the central axis of each detector points toward the center of the hemisphere, and we optimize the size of the detector crystal block to be arranged on the helmet detector. We simulate the spherical arrangement with the optimized crystal block size and compare its imaging performance with the multi-ring arrangement, which has a similar detector arrangement to that of our first prototype. We conduct Monte Carlo simulation to model the scanners having the 4-layer DOI detectors which consist of LYSO crystals. A dead space of 2 mm is assumed on each side of the crystal blocks such as for wrapping. The size of the crystal block is varied from 4×4 mm2 to 54×54 mm2 while fixing the thickness of the crystal block to 20 mm. We find that the crystal block sized at 42×42 mm2 has the highest sensitivity for a hemispherical phantom. The comparison of the two arrangements with the optimized crystal blocks show that, for the same number of crystal blocks, the spherical arrangement has 17% higher sensitivity for the hemispherical phantom than the multi-ring arrangement. We conclude that the helmet-chin PET with the spherical arrangement constructed from the crystal block sized at 42×42×20 mm3 has better imaging performance especially at the upper part of the brain compared to the multi-ring arrangement while keeping similar spatial resolution throughout the FOV. |
| Databáze: | OpenAIRE |
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