Abstract The measurement accuracy of stereotactic radiotherapy (SRT) patient-specific quality assurance (QA) is challenging as small-field dosimetry contains lateral charge disequilibrium, partial blocking of the beam source, and limitations based on the detector size. The aim of this study was to investigate the dosimetric characteristics of a two-dimensional high-resolution silicon diode array for SRT end-to-end patient-specific QA. The dosimetric characteristics of the diode array, delivered to an end-to-end QA phantom, were evaluated for 6 MV, with a flattening filter (FF) and flattening filter-free (FFF), and 10 MV FFF photon beams. Dose linearity, dose rate dependence, dose-per-pulse dependence, field size dependence, angular dependence, and beam directivity were investigated for all photon beams. A total of 27 clinical plans were selected to evaluate the SRT end-to-end patient-specific QA for treatment delivery using volumetric modulated arc therapy (VMAT). For all beam qualities, the differences of dose and dose rate linearity of the diode array were below 0.7% (10–1400 MU range) and 0.6% (100–2400 MU/min range), respectively. The diodes had a decrease in sensitivity of about 4% for the 21-fold decrease in dose-per-pulse. Output factors were in good agreement for field size down to 2 × 2 cm2 ( The diode array, with several corrections, demonstrated good dosimetric characteristics for SRT QA. The GPRs of end-to-end patient-specific QA for non-coplanar and multiple metastases were as high as that for coplanar and single-target, and a gamma criterion of 2%/1 mm would be suitable for SRT QA when using the array.

中文翻译：

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用于立体定向放射治疗端到端患者特定 QA 的 2D 硅二极管阵列的剂量学特性

摘要 立体定向放射治疗 (SRT) 患者特定质量保证 (QA) 的测量精度具有挑战性，因为小场剂量测定包含侧向电荷不平衡、光束源的部分阻挡以及基于探测器尺寸的限制。本研究的目的是研究用于 SRT 端到端患者特定 QA 的二维高分辨率硅二极管阵列的剂量学特性。传输到端到端 QA 体模的二极管阵列的剂量学特性被评估为 6 MV，具有平坦滤波器 (FF) 和平坦无滤波器 (FFF)，以及 10 MV FFF 光子束。研究了所有光子束的剂量线性、剂量率相关性、每脉冲剂量相关性、场大小相关性、角度相关性和光束方向性。总共选择了 27 个临床计划来评估 SRT 端到端患者特定的质量保证，以使用容积调制弧疗法 (VMAT) 进行治疗。对于所有光束质量，二极管阵列的剂量和剂量率线性差异分别低于 0.7%（10-1400 MU 范围）和 0.6%（100-2400 MU/min 范围）。对于每脉冲剂量降低 21 倍，二极管的灵敏度降低了约 4%。对于低至 2 × 2 cm2 的场大小，输出因子非常一致（二极管阵列经过多次校正，证明了 SRT QA 的良好剂量学特性。非共面和多重患者的端到端患者特定 QA 的 GPR转移与共面和单靶点一样高，使用阵列时 2%/1 mm 的伽马标准适用于 SRT QA。