Simplified phantom for electron density calibration by dual-energy CT

• Project/Area Number: 16K09011
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Medical Physics and Radiological Technology
• Research Institution: Niigata University
• Principal Investigator: Saito Masatoshi 新潟大学, 医歯学系, 教授 (40241583)
• Research Collaborator: HAYAKAWA Takahide
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000); Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: electron density / dual-energy CT / treatment planning / 放射線

Outline of Final Research Achievements

The purpose of this research is to develop a simple phantom for electron density calibration necessary to calculating dose distribution in a radiation treatment plan of cancer using dual-energy CT. The basic performance of this simple phantom built in the study was checked through electron density calibration of a known standard substance. It was found that an excellent linear relationship is formed between the energy-subtracted CT values and the electron densities. The obtained electron density values could be determined within 1-2% errors.

Academic Significance and Societal Importance of the Research Achievements

これまでの電子密度ファントムは、人体組織に極めて近いロッド素材の選択・合成とその正確な電子密度の見積りが要求され、必要な組織等価ロッドの本数も多くなるため、結果的に高価なものになっていた。Dual-energy CTを活用することにより、従来の高価な材料を用いずとも、より安価で入手が容易な材料で構成されるファントムを使用しても、放射線治療計画に不可欠な高精度の電子密度校正が十分可能となることが期待できる。

Research Products

• [Journal Article] Simulation of photon-counting detectors for conversion of dual-energy-subtracted computed tomography number to electron density (2019)
  • Author(s): Saito Masatoshi
  • Journal Title: Radiological Physics and Technology Volume: 12 Issue: 1 Pages: 105-117
  • DOI: 10.1007/s12194-018-00497-0
  • NAID: 130007919661
  • Peer Reviewed
• [Journal Article] A simple formulation for deriving effective atomic numbers via electron density calibration from dual-energy CT data in the human body (2017)
  • Author(s): Saito Masatoshi、Sagara Shota
  • Journal Title: Medical Physics Volume: 44 Issue: 6 Pages: 2293-2303
  • DOI: 10.1002/mp.12176
  • Peer Reviewed
• [Journal Article] Simplified derivation of stopping power ratio in the human body from dual-energy CT data (2017)
  • Author(s): Saito Masatoshi、Sagara Shota
  • Journal Title: Medical Physics Volume: 44 Issue: 8 Pages: 4179-4187
  • DOI: 10.1002/mp.12386
  • Peer Reviewed / Open Access
• [Presentation] A simple formulation for deriving stopping power ratio in the human body from dual-energy CT data (2018)
  • Author(s): Masatoshi Saito and Shota Sagara
  • Organizer: 日本医学物理学会第115回学術大会
• [Presentation] A simple formulation for deriving effective atomic numbers via electron density calibration from dual-energy CT data in the human body (2018)
  • Author(s): Shota Sagara and Masatoshi Saito
  • Organizer: 日本医学物理学会第116回学術大会