Clinical effectiveness of four-dimensional dose distribution calculation for a tracking irradiation

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K09078
• 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: National Cancer Center Japan
• Principal Investigator: Tachibana Hidenobu 国立研究開発法人国立がん研究センター, 先端医療開発センター, 医学物理専門職 (20450215)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 四次元計算 / 線量計算 / 非剛体レジストレーション

Outline of Final Research Achievements

We developed a dose calculation engine and a non-rigid registration engine, which are two important points in the development of a quality assurance system using four-dimensional dose calculation. The Collapse Cone Convolution Algorithm was adopted as the dose calculation engine and implemented. As a result, it was confirmed that the calculation accuracy was equivalent to that of the treatment planning device. On the other hand, it was found that the calculation time of this program was very long, and this speedup was decided to be carried over to 2020. Acceleration of non-rigid registration has been completed. Development of a GUI that integrates these two points has been completed. In FY2020, the development of a quality assurance system using four-dimensional dose calculation will be completed, and its effectiveness will be verified.

Free Research Field

医学物理学

Academic Significance and Societal Importance of the Research Achievements

放射線治療の新しい技術として動いている腫瘍を追尾して照射する追尾照射がある。通常の照射方では腫瘍の外の正常臓器へも照射する必要があるが、追尾照射方法は腫瘍の周りの正常臓器を極力打たなくて済む。したがって、副作用が小さく、また腫瘍への線量増加が可能で腫瘍制御率の向上が期待できる。
一方、複雑な治療法であり、実際治療計画の際は実際の患者体内の線量分布を確認できていない。そこで、その追尾照射を確認できる方法である四次元線量計算を利用した品質保証システムの開発を行った。このシステムにより不明であった追尾照射の線量分布が明らかになり、さらなる治療法の向上が見込める。