Wang Yiling, Yin Gang, Wang Jie, Zhao Yue, Liu Min, Lang Jinyi
Sichuan Cancer Hospital & Institute, School of Medicine, University of Electronic Science and Technology of China, Radiation Oncology Key Laboratory of Sichuan Province, Chengdu, China.
The First People's Hospital of Liangshan, Liangshan Yi Autonomous Prefecture, Sichuan, China.
Dose Response. 2021 Apr 8;19(2):15593258211001676. doi: 10.1177/15593258211001676. eCollection 2021 Apr-Jun.
To investigate a novel gamma analysis system for dose verification results in terms of clinical significance.
The modified scheme redefined the computational domain of the conventional gamma analysis with the projections of beams and the regions of interest (ROI). We retrospectively studied 6 patients with the conventional and the modified gamma analysis schemes while compared their performances. The cold spots ratio of the planning target volume (PTV) and the hot spots ratio of the organs at risk (OAR) were also computed by the modified scheme to assess the clinical significance.
The result of the gamma passing rate in the modified method was conformable to that in the conventional method with a cut-off threshold of 5%. The cold spots ratio of PTV and hot spots ratio of OAR were able to be evaluated by the modified scheme. For an introduced 7.1% dose error, the discrimination ratio in gamma passing rate of the conventional method was lower than 2%, while it was improved to 5% by the modified method.
The modified gamma analysis scheme had a comparable quality as the conventional scheme in terms of dose inspection. Besides, it could improve the clinical significance of the QA result and provide the assessment for ROI-specific discrepancy. The modified scheme could also be conveniently integrated into the conventional dose verification process, benefiting the less developed regions where high-end 3D dose verification devices are not affordable.
从临床意义方面研究一种用于剂量验证结果的新型伽马分析系统。
改进方案通过射束投影和感兴趣区域（ROI）重新定义了传统伽马分析的计算域。我们回顾性研究了6例采用传统和改进伽马分析方案的患者，并比较了它们的性能。还通过改进方案计算了计划靶体积（PTV）的冷点比率和危及器官（OAR）的热点比率，以评估临床意义。
改进方法中伽马通过率的结果与传统方法在截止阈值为5%时的结果一致。改进方案能够评估PTV的冷点比率和OAR的热点比率。对于引入的7.1%剂量误差，传统方法在伽马通过率方面的辨别率低于2%，而改进方法将其提高到了5%。
改进的伽马分析方案在剂量检查方面与传统方案具有相当的质量。此外，它可以提高质量保证结果的临床意义，并为特定ROI差异提供评估。改进方案还可以方便地集成到传统剂量验证过程中，有利于那些负担不起高端3D剂量验证设备的欠发达地区。
