Shi Chengyu, Chen Qing, Yu Francis, Zhang Jingqiao, Kang Minglei, Tang Shikui, Chang Chang, Lin Haibo
New York Proton Center, New York, NY, USA.
Texas Proton Therapy Center, Dallas, TX, USA.
J Appl Clin Med Phys. 2021 Jan;22(1):117-127. doi: 10.1002/acm2.13117. Epub 2020 Dec 18.
The Daily Quality Assurance (DQA) for a proton modality is not standardized. The modern pencil beam scanning proton system is becoming a trend and an increasing number of proton centers with PBS are either under construction or in planning. The American Association of Physicists in Medicine has a Task Group 224 report published in 2019 for proton modality routine QA. Therefore, there is a clinical need to explore a DQA procedure to meet the TG 224 guideline. The MatriXX PT and a customized phantom were used for the dosimetry constancy checking. An OBI box was used for imaging QA. The MyQA(TM) software was used for logging the dosimetry results. An in-house developed application was applied to log and auto analyze the DQA results. Another in-house developed program "DailyQATrend" was used to create DQA databases for further analysis. All the functional and easy determined tasks passed. For dosimetry constancy checking, the outputs for four gantry rooms were within ±3% with room to room baseline differences within ±1%. The energy checking was within ±1%. The spot location checking from the baseline was within 0.63 mm and the spot size checking from the baseline was within -1.41 ± 1.27 mm (left-right) and -0.24 ± 1.27 mm (in-out) by averaging all the energies. We have found that there was also a trend for the beam energies of two treatment rooms slowly going down (0.76% per month and 0.48 per month) after analyzing the whole data trend with linear regression. A DQA program for a PBS proton system has been developed and fully implemented into the clinic. The DQA program meets the TG 224 guideline and has web-based logging and auto treading functions. The clinical data show the DQA program is efficient and has the potential to identify the PBS proton system potential issue.
质子治疗模式的每日质量保证（DQA）尚未标准化。现代笔形束扫描质子系统正成为一种趋势，越来越多采用笔形束扫描的质子中心正在建设或规划中。美国医学物理师协会于2019年发布了关于质子治疗模式常规质量保证的任务组224报告。因此，临床上需要探索一种符合TG 224指南的DQA程序。使用MatriXX PT和定制体模进行剂量测定稳定性检查。使用OBI箱进行成像质量保证。使用MyQA(TM)软件记录剂量测定结果。应用一个内部开发的应用程序来记录和自动分析DQA结果。另一个内部开发的程序“DailyQATrend”用于创建DQA数据库以进行进一步分析。所有功能和易于确定的任务均通过。对于剂量测定稳定性检查，四个机架室的输出在±3%以内，室间基线差异在±1%以内。能量检查在±1%以内。从基线起的光斑位置检查在0.63毫米以内，通过对所有能量求平均，从基线起的光斑尺寸检查在左右方向为-1.41±1.27毫米，进出方向为-0.24±1.27毫米。通过线性回归分析整个数据趋势后，我们发现两个治疗室的束流能量也有缓慢下降的趋势（每月分别下降0.76%和0.48%）。已开发出一种用于笔形束扫描质子系统的DQA程序并已全面应用于临床。该DQA程序符合TG 224指南，并具有基于网络的记录和自动跟踪功能。临床数据表明该DQA程序高效，有潜力识别笔形束扫描质子系统的潜在问题。
