State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, P. R. China.
Department of Radiation Oncology, Zhuzhou Hospital Affiliated to Xiangya School of Medicine, Central South University, Zhuzhou, P. R. China.
J Appl Clin Med Phys. 2024 Apr;25(4):e14258. doi: 10.1002/acm2.14258. Epub 2024 Jan 4.
We aimed to perform the commissioning and clinical evaluation of myQA SRS detector array for patient-specific quality assurance (PSQA) of stereotactic radiosurgery (SRS)/ stereotactic body radiotherapy (SBRT) plans.
To perform the commissioning of myQA SRS, its dose linearity, dose-rate dependence, angular dependence, and field-size dependence were investigated. Ten SBRT plans were selected for clinical evaluation: 1) Common clinical deviations based on the original SBRT plan (Plan0), including multileaf collimator (MLC) positioning deviation and treatment positioning deviation were introduced. 2) Compared the performance of the myQA SRS and a high-resolution EPID dosimetry system in PSQA measurement for the SBRT plans. Evaluation parameters include gamma passing rate (GPR) and distance-to-agreement (DTA) pass rate (DPR).
The dose linearity, angle dependence, and field-size dependence of myQA SRS system exhibit excellent performance. The myQA SRS is highly sensitive in the detection of MLC deviations. The GPR of (3%/1 mm) decreases from 90.4% of the original plan to 72.7%/62.9% with an MLC outward/inward deviation of 3 mm. Additionally, when the setup error deviates by 1 mm in the X, Y, and Z directions with the GPR of (3%/1 mm) decreasing by an average of -20.9%, -25.7%, and -24.7%, respectively, and DPR (1 mm) decreasing by an average of -33.7%, -32.9%, and -29.8%. Additionally, the myQA SRS has a slightly higher GPR than EPID for PSQA, However, the difference is not statistically significant with the GPR of (3%/1 mm) of (average 90.4%% vs. 90.1%, p = 0.414).
Dosimetry characteristics of the myQA SRS device meets the accuracy and sensitivity requirement of PSQA for SRS/SBRT treatment. The dose rate dependence should be adequately calibrated before its application and a more stringent GPR (3%/1 mm) evaluation criterion is suggested when it is used for SRS/SBRT QA.
我们旨在对 myQA SRS 探测器阵列进行调试和临床评估，以实现立体定向放射外科（SRS）/立体定向体放射治疗（SBRT）计划的患者特定质量保证（PSQA）。
为了进行 myQA SRS 的调试，我们研究了其剂量线性度、剂量率依赖性、角度依赖性和射野尺寸依赖性。选择了 10 个 SBRT 计划进行临床评估：1）基于原始 SBRT 计划（Plan0）的常见临床偏差，包括多叶准直器（MLC）定位偏差和治疗定位偏差。2）比较了 myQA SRS 和高分辨率 EPID 剂量测量系统在 SBRT 计划 PSQA 测量中的性能。评估参数包括伽马通过率（GPR）和距离一致性（DTA）通过率（DPR）。
myQA SRS 系统的剂量线性度、角度依赖性和射野尺寸依赖性表现出色。myQA SRS 对 MLC 偏差的检测非常敏感。当 MLC 向外/向内偏差为 3mm 时，（3%/1mm）的 GPR 从原始计划的 90.4%下降到 72.7%/62.9%。此外，当 X、Y 和 Z 方向的设置误差分别为 1mm 时，GPR 平均下降-20.9%、-25.7%和-24.7%，DPR（1mm）平均下降-33.7%、-32.9%和-29.8%。此外，myQA SRS 在 PSQA 方面的 GPR 略高于 EPID，但差异无统计学意义，（3%/1mm）的 GPR 平均值分别为 90.4%和 90.1%，p=0.414）。
myQA SRS 设备的剂量学特性满足 SRS/SBRT 治疗 PSQA 的准确性和灵敏度要求。在应用前应充分校准剂量率依赖性，并且建议在用于 SRS/SBRT QA 时使用更严格的 GPR（3%/1mm）评估标准。
