Development of narrow-pitch TlBr gamma-ray detectors for SPECT

• Project/Area Number: 17H05076
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Medical Physics and Radiological Technology
• Research Institution: Tohoku Institute of Technology
• Principal Investigator: Onodera Toshiyuki 東北工業大学, 工学部, 准教授 (10620916)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥24,700,000 (Direct Cost: ¥19,000,000、Indirect Cost: ¥5,700,000); Fiscal Year 2019: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000); Fiscal Year 2018: ¥7,670,000 (Direct Cost: ¥5,900,000、Indirect Cost: ¥1,770,000); Fiscal Year 2017: ¥14,820,000 (Direct Cost: ¥11,400,000、Indirect Cost: ¥3,420,000)
• Keywords: TlBr / 化合物半導体 / ガンマ線検出器 / 臭化タリウム / SPECT / 結晶成長

Outline of Final Research Achievements

In this study, gamma-ray detector fabrication techniques have been developed for realizing a high resolution single photon emission tomography (SPECT) using a thallium bromide (TlBr) semiconductor crystal.
Photolithography techniques has been studied using negative, positive and liftoff type resist and electrode formation process using liftoff type resist was most promising for fine pitch electrode formation on TlBr crystals. TlBr crystals were grown inside substrates made from aluminum oxide and quartz. 3 mm diameters and 1 mm diameters for fifth single TlBr crystals were successfully grown in the substrates.

Academic Significance and Societal Importance of the Research Achievements

ＳＰＥＣＴに搭載されるガンマ線センサーとしてＴｌＢｒ半導体は、他の半導体を大きく凌ぐ優れた特長を持っているため、実現できれば従来の診断機器よりも高解像度化や低被曝化などの恩恵が期待出来るが、未だに実用化は果たしていない。本研究は、ＴｌＢｒ検出器のＳＰＥＣＴへの実用化を加速させるため装置開発に有益な新たな技術を従来の常識にとらわれることなく多角的な方面から検討を進めた。得られた知見が今後の研究開発に活かされることにより、多くの国民が享受できる先進医療の促進が期待できる。

Research Products

• [Journal Article] Evaluation of Antimony Tri-Iodide Crystals for Radiation Detectors (2018)
  • Author(s): Onodera Toshiyuki、Baba Koei、Hitomi Keitaro
  • Journal Title: Science and Technology of Nuclear Installations Volume: 2018 Pages: 1-7
  • DOI: 10.1155/2018/1532742
  • Peer Reviewed / Open Access
• [Presentation] Lift-off photolithography process for electrode preparation of TlBr gamma-ray detectors (2020)
  • Author(s): T.Onodera and K.Hitomi
  • Organizer: Eighth International Conference on Radiation in Various Fields of Research
  • Int'l Joint Research
• [Presentation] Photoresist on thallium bromide crystals for gamma-ray detector fabrication (2019)
  • Author(s): T.Onodera and K.Hitomi
  • Organizer: Seventh International Conference on Radiation in Various Fields of Research
  • Int'l Joint Research
• [Presentation] フォトリソグラフィを用いたTlBr検出器の電極形成 (2019)
  • Author(s): 小野寺敏幸、人見啓太朗
  • Organizer: 秋季第79回応用物理学会学術講演会
• [Presentation] Growth of TlBr semiconductor crystals in ceramic substrates for gamma-ray detector fabrication (2018)
  • Author(s): T. Onodera, K. Hitomi, T. Shoji
  • Organizer: Sixth international conference on radiation and applications in various fields of research
  • Int'l Joint Research
• [Presentation] TlBrガンマ線検出器の移動度と寿命時間 (2018)
  • Author(s): 小野寺敏幸、人見啓太朗
  • Organizer: 秋季第78回応用物理学会学術講演会
• [Presentation] Experimental results from purification of TlBr semiconductor crystals by the filter method for Use as gamma-ray detectors (2017)
  • Author(s): T. Onodera, K. Hitomi, T. Shoji
  • Organizer: CSI 2017 Pisa 40th Colloquium Spectroscopicum Internationale
  • Int'l Joint Research
• [Presentation] 狭ピッチTlBrガンマ線検出器の初期検討 (2017)
  • Author(s): 小野寺敏幸、人見啓太朗、庄司忠良
  • Organizer: 秋季第77回応用物理学会学術講演会