Development of fast-type GAGG scintillator for realizing higher performance PET system

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H05986
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Optical engineering, Photon science
• Research Institution: Tohoku University
• Principal Investigator: Kamada Kei 東北大学, 未来科学技術共同研究センター, 准教授 (60639649)
• Research Collaborator: USUKI Yoshiyuki
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: シンチレータ / 放射線 / 結晶成長 / 核医学

Outline of Final Research Achievements

In this research, we have optimized the crystal composition, surface treatment, and annealing condition for maximizing scintillator properties of fast-type GAGG single crystal with co-doping. As a result, we found a composition with a scintillation decay time of 36 ns and a timing resolution of 160 ps while keeping the light yield. Furthermore, we advanced development of large-scale crystal growth technology for fast-type GAGG. In addition to the adjustment of the temperature gradient by the examination of the heat insulating material arrangement condition, the coil position, the growth atmosphere, and the rotation speed were optimized, and the crystal of 3 inches in diameter x 150 mm in length was stably produced. With the cooperation of Furukawa Scintitech Co., Ltd., the fast-type GAGG was mounted on a PET device, and a resolution of 0.98 mm FWHM and a sensitivity of 1.31% were achieved.

Free Research Field

結晶工学

Academic Significance and Societal Importance of the Research Achievements

癌細胞の検知やアルツハイマー病の部位の同定などにポジトロン断層法（positron emission tomography：PET）が用いられている。高性能なPET装置の開発には、高速かつ高効率で高感度、高いエネルギー分解能を有するシンチレータの研究開発が重要となる。本研究の成果である、高速型GAGGシンチレータを、PET装置に搭載することで、位置分解能、感度、S/N比の向上が可能であり、がん診断の高精度化に繋がる。また事故放射能の無いGAGGを用いることで、PETを革新する、コンプトンPETカメラなどの新規医療画像装置の開発が進む。新規学術分野の発展や、医療分野の社会的貢献につながる。