Planning and optimization of dose distribution based on biological effectiveness of carbon ion radiotherapy for osteosarcoma

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K16751
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Shonan Kamakura General Hospital, Medical Corporation Tokushukai (Center for Clinical and (2022-2023); Gunma University (2020-2021)
• Principal Investigator: Shiba Shintaro 医療法人徳洲会湘南鎌倉総合病院(臨床研究センター), 湘南先端医学研究所 放射線医学研究部, 主任研究員 (90826950)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 重粒子線治療 / 骨肉腫 / 生物学的効果 / 線量分布図

Outline of Final Research Achievements

The clinical outcomes of carbon-ion radiotherapy for bone and soft tissue tumors treated at the Gunma University Heavy Ion Medical Center were analyzed and reported. In addition, in vitro experiments were conducted to study the cell-killing effect of changing the linear energy transfer (LET) of carbon-ion beams and the change in the sensitizing effective rate of chemotherapy.
The relative biological effectiveness (RBE) of human salivary gland cells is used in actual treatment planning. In the present study, carbon-ion beam irradiation of human osteosarcoma cells at various LETs was performed to obtain their respective RBEs, which were then used to create osteosarcoma cell-specific dose distributions. The results showed that the dose distribution was degraded, especially in the homogeneity index of the dose-volume histogram parameter. The analysis of the tumor-specific dose distribution was reported in a journal article.

Free Research Field

放射線治療

Academic Significance and Societal Importance of the Research Achievements

今回の研究で行った、重粒子線治療の異なる線エネルギー付与(LET)における殺細胞効果の違いの研究や腫瘍特異的RBEを用いた線量分布の最適化は、LET最適化線量分布の作成やマルチイオン照射の研究といった、今後の重粒子線治療の局所効果向上のための研究の礎となると考える。また、患者さんにとって局所効果の向上は生存に寄与すると考えられるので研究成果の学術的意義は大きいと考える。