Respiratory movement of the target in body radiation therapy: analysis with four-dimensional algorithm and standardization of treatment

• Project/Area Number: 17K10486
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Radiation science
• Research Institution: Yokohama City University
• Principal Investigator: HATA Masaharu 横浜市立大学, 医学研究科, 教授 (60285145)
• Project Period (FY): 2017-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2017: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
• Keywords: 放射線治療 / 体幹部 / 呼吸性移動 / 呼吸同期

Outline of Final Research Achievements

In this study, it was examined how respiratory movement of the target in body radiation therapy had an effect on radiation dose.
As a result, it was shown that the quality of radiation dose (distribution) was warranted if the respiratory movement of the target was relatively small (within approximately 10 mm or less). In contrast, if it was larger, an unexpected lower or higher radiation dose that could cause the reduced efficacy or enhanced toxicities might be delivered.

Academic Significance and Societal Importance of the Research Achievements

昨今の放射線治療の進歩は著しく、中でも最も進んだ治療の一つである強度変調放射線治療が我が国でも普及しつつある。この治療では、線量の異なる部分を重ね合わせていく高度な照射技術が用いられるため、呼吸によって移動する標的に対して必要な領域に予想通りの線量が照射されているか不確かな部分がある。
今回、この標的の移動がどの程度までなら精度の高い線量（域）が担保されるのかを示した。今後、益々適用の機会が増えるであろう強度変調放射線治療において、標的の呼吸性移動対策の必要性の有無を示すものである。