量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum and Radiological Science and Technology.
Thank you very much for using our website. On the 11th of March 2019, this site was moved from our own network server to the JAIRO Cloud network server. If you previously bookmarked this site, that bookmark will no longer work. We would be grateful if you could bookmark the website again. Thank you very much for your understanding and cooperation.
One of the challenging applications of PET is implementing it for in-beam PET, which is an in situ monitoring method for charged particle therapy. For this purpose, we have previously proposed two geometries for our open-type PET scanners named OpenPET. The original OpenPET had a physically opened field-of-view (FOV) between two detector rings through which irradiation beams pass. This dual-ring OpenPET (DROP) had a wide axial FOV including the gap. But, this geometry is not necessarily the most efficient for application to in-beam PET in which only a limited FOV around the irradiation field is required. Therefore, we proposed a single-ring OpenPET (SROP) geometry which can provide an accessible and observable open space with higher sensitivity and a reduced number of detectors compared to DROP. Also, we proposed two arrangement types, a slanted ellipse (SE) type where oval detector rings are slanted and stacked and an axial shift (AS) type where block detectors originally forming a conventional PET scanner are axially shifted little by little. Previously, we developed the SE-SROP prototype, and showed its good performance for in-beam PET. However, the SE-SROP decreased sensitivity slightly relative to the ring-type PET and needed a large gantry in the axial direction for conventional PET studies. On the other hand, AS-SROP can transform conventional ring-type PET scanners into stacked detectors with a gradual axial shift. In this work, we developed and evaluated a small AS-SROP prototype for proof-of-concept. The AS-SROP prototype was designed with 2 cylinder-shaped detector rings of 16 DOI detectors. The system sensitivity and spatial resolution were measured and were 5.1% and 2.6 mm, respectively, for the OpenPET mode. For the conventional PET mode, the system sensitivity and spatial resolution were 7.3% and 2.2 mm, respectively. We concluded that the AS-SROP geometry has a good potential for not only in-beam imaging but also conventional PET studies.
会議概要（会議名, 開催地, 会期, 主催者等）
The 2013 IEEE Nuclear Science Symposium and Medical Imaging Conference, and Room-Temperature Semiconductor X-Ray and Gamma-Ray Detectors workshop
Performance Evaluation of a Transformable Axial-Shift Type Single-Ring OpenPET
