Reconstruction of dose distributions using PET images in heavy ion therapy

• Project/Area Number: 20K08066
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: Mohammadi Akram 国立研究開発法人量子科学技術研究開発機構, 量子医科学研究所 先進核医学基盤研究部, 主任研究員 (10554735)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2022: ¥260,000 (Direct Cost: ¥200,000、Indirect Cost: ¥60,000); Fiscal Year 2021: ¥2,730,000 (Direct Cost: ¥2,100,000、Indirect Cost: ¥630,000); Fiscal Year 2020: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
• Keywords: dose reconstruction / PET image / ion therapy

Outline of Research at the Start

患者体内におけるビームの飛程確認は、粒子線治療の利点を最大化するために重要である。PETは、入射粒子と生体組織との反応から生成される陽電子放出核種を検出するために、最も広く研究されている方法であるが、実際に付与された線量を推定し、計画線量と直接比較する手法はまだ確立されていない。本研究では、PET画像から線量分布を再構成する手法を開発し、11Cを用いた治療前の飛程検証、及び計画線量との直接比較を可能にすることを目的とする。まず、均質なファントムや不均質なファントムに対して様々な分布の線量を照射し、推定手法の精度の評価を行う。そして、臨床相当のビームに対して適用し評価することで実現可能性を明らかにする。

Outline of Annual Research Achievements

An algorithm for prediction of depth doses from PET images for 11C and 15O ion beams was developed for the first time. The depth doses and PET images were measured in polymethyl methacrylate (PMMA) phantoms for mono-energetic and poly-energetic ion beams in the carbon therapy facility of the Heavy Ion Medical Accelerator in Chiba (HIMAC). PET images of the mono-energetic ion beams were used to reproduce the measured PET activity of the poly-energetic ion beams and then the depth doses were calculated using the proposed algorithm. The predicted dose profiles were in overall good agreement with the measured ones and the distal fall-off positions at 80% of the Bragg peaks were also predicted within 0.2 mm for both 11C and 15O ion beams.

Research Products

• [Journal Article] Development of dual-ended depth-of-interaction detectors using laser-induced crystals for small animal PET systems (2021)
  • Author(s): Mohammadi Akram、Inadama Naoko、Nishikido Fumihiko、Yamaya Taiga
  • Journal Title: Physics in Medicine and Biology Volume: 66 Issue: 17 Pages: 175029-175029
  • DOI: 10.1088/1361-6560/ac18fc
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Dose estimation from in-beam PET imaging of 11C and 15O beams (2023)
  • Author(s): Akram Mohammadi, Hideaki Tashima, Sodai Takyu, Yuma Iwao, Chie Toramatsu, Fumihiko Nishikido, Katia Parodi, and Taiga Yamaya
  • Organizer: 2023 NSS MIC RTSD (2023 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference)
  • Int'l Joint Research
• [Presentation] PET-based range verification of 11C ion beam with SOBP (2022)
  • Author(s): Akram Mohammadi
  • Organizer: 2022 IEEE NSS MIC RTSD (2022 IEEE Nuclear Science Symposium, Medical Imaging Conference and Room Temperature Semiconductor Detector Conference)
  • Int'l Joint Research