The Centre for Vision Speech and Signal Processing (CVSSP), University of Surrey, Guildford, Surrey, United Kingdom.
Metrology for Medical Physics (MEMPHYS), National Physical Laboratory, Teddington, United Kingdom.
Phys Med Biol. 2021 Feb 25;66(5):055021. doi: 10.1088/1361-6560/abe053.
To develop and demonstrate an end-to-end assessment procedure for adaptive radiotherapy (ART) within an MR-guided system.
A 3D printed pelvic phantom was designed and constructed for use in this study. The phantom was put through the complete radiotherapy treatment chain, with planned internal changes made to model prostate translations and shape changes, allowing an investigation into three ART techniques commonly used. Absolute dosimetry measurements were made within the phantom using both gafchromic film and alanine. Comparisons between treatment planning system (TPS) calculations and measured dose values were made using the gamma evaluation with criteria of 3 mm/3% and 2 mm/2%.
Gamma analysis evaluations for each type of treatment plan adaptation investigated showed a very high agreement with pass rates for each experiment ranging from 98.10% to 99.70% and 92.60% to 97.55%, for criteria of 3%/3 mm and 2%/2 mm respectively. These pass rates were consistent for both shape and position changes. Alanine measurements further supported the results, showing an average difference of 1.98% from the TPS.
The end-to-end assessment procedure provided demanding challenges for treatment plan adaptations to demonstrate the capabilities and achieved high consistency in all findings.
在 MR 引导系统内开发并展示用于自适应放疗（ART）的端到端评估流程。
本研究设计并构建了一个用于 3D 打印的骨盆模型。该模型经历了完整的放射治疗流程，内部计划进行了前列腺平移和形状变化的改变，以调查三种常用于 ART 的技术。利用 Gafchromic 胶片和丙氨酸在模型中进行绝对剂量测量。使用 3mm/3%和 2mm/2%的伽马评估标准，对治疗计划系统（TPS）计算值与测量剂量值进行了比较。
对所研究的每种治疗计划自适应类型的伽马分析评估显示，其通过率非常高，每次实验的通过率分别为 98.10%至 99.70%和 92.60%至 97.55%，伽马评估标准分别为 3%/3mm 和 2%/2mm。这些通过率在形状和位置变化方面是一致的。丙氨酸测量进一步支持了结果，显示与 TPS 的平均差异为 1.98%。
端到端评估流程为治疗计划适应提供了苛刻的挑战，证明了其能力，并在所有发现中具有高度一致性。
