Development of a new optimization system to mitigate plan complexity for VMAT

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15782
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: Kyoto University
• Principal Investigator: Ono Tomohiro 京都大学, 医学研究科, 特定助教 (90782657)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: VMAT / QA / 最適化

Outline of Final Research Achievements

A new VMAT optimization system was developed by identifying the causes of the discrepancy between the planned dose and the measured dose in volumetric-modulated arc therapy (VMAT) with complex irradiation techniques and optimizing to improve plan quality as following; (1) identifying the irradiation parameters that affect the plan complexity of the VMAT plan and analyzing the complexity index, (2) modifying the irradiation shape of the VMAT plan to the optimal position, and (3) quantitatively evaluating the usefulness of the plan before and after modification to develop an optimization system to reduce plan complexity. system, and these results were accepted by an international academic journal.

Free Research Field

医学物理学

Academic Significance and Societal Importance of the Research Achievements

VMATプランの複雑さを軽減する手法として、米国Varian社の治療計画装置より(Aperture Shape Controller: ASC)という機能が搭載された。ASCは照射野を形成するMLCの位置変化を抑え、プランの複雑さを軽減するという機能である。しかしASC機能が必ずしも計算値と実測値の乖離を軽減するとは限らない。本研究における最適化手法はQA予測システムに基づき、計算値と実測値の乖離を少なくかつ複雑さを軽減するものであり、国内外の何れにおいても未だ報告はない。将来的にはQA結果を見越しプランを修正する効率的な最適化手法として、高精度放射線治療の発展と普及に大いに貢献すると考える。