The present study aimed to dosimetrically evaluate the small-fields of a 6 MV flattening filter-free (FFF) photon beam using different detectors. The 6 MV FFF photon beam was used for measurement of output factor, depth dose, and beam profile of small-fields of sizes 0.6 cm × 0.6 cm to 6.0 cm × 6.0 cm. The five detectors used were SNC125c, PinPoint, EDGE, EBT3, and TLD-100. All measurements were performed as per the International Atomic Energy Agency TRS 483 protocol. Output factors measured using different detectors as direct reading ratios showed significant variation for the smallest fields, whereas after correcting them according to TRS 483, all sets of output factors were nearly compatible with each other when measurement uncertainty was also considered. The beam profile measured using SNC125c showed the largest penumbra for all field sizes, whereas the smallest was recorded with EDGE. Compared with that of EBT3, the surface dose was found to be much higher for all the other detectors. PinPoint, EBT3, TLD-100, and EDGE were found to be the detector of choice for small-field output factor measurements; however, PinPoint needs special attention when used for the smallest field size (0.6 cm × 0.6 cm). EDGE and EBT3 are optimal for measuring beam profiles. EBT3, PinPoint, and EDGE can be selected for depth dose measurements, and EBT3 is suitable for surface dose estimation.

中文翻译：

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使用各种检测器对6 MV展平的无滤波器小光子束进行剂量测定。

本研究旨在使用不同的检测器剂量学评估6 MV展平无滤光片（FFF）光子束的小视场。6 MV FFF光子束用于测量输出因子，深度剂量和尺寸为0.6 cm×0.6 cm至6.0 cm×6.0 cm的小视场的光束轮廓。使用的五个检测器是SNC125c，PinPoint，EDGE，EBT3和TLD-100。所有测量均按照国际原子能机构TRS 483协议进行。使用不同的检测器作为直接读取率测量的输出因子在最小场上显示出显着变化，而根据TRS 483对其进行校正后，考虑到测量不确定性时，所有输出因子集几乎彼此兼容。使用SNC125c测量的光束轮廓在所有视场尺寸下均显示出最大的半影，而最小的是用EDGE记录的。与EBT3相比，所有其他检测器的表面剂量都高得多。发现PinPoint，EBT3，TLD-100和EDGE是小场输出因子测量的首选检测器。但是，PinPoint在用于最小的场尺寸（0.6厘米×0.6厘米）时需要特别注意。EDGE和EBT3是测量光束轮廓的最佳选择。可以选择EBT3，PinPoint和EDGE进行深度剂量测量，而EBT3适合进行表面剂量估计。当使用最小的场尺寸（0.6厘米×0.6厘米）时，PinPoint需要特别注意。EDGE和EBT3是测量光束轮廓的最佳选择。可以选择EBT3，PinPoint和EDGE进行深度剂量测量，而EBT3适合进行表面剂量估计。当使用最小的场尺寸（0.6厘米×0.6厘米）时，PinPoint需要特别注意。EDGE和EBT3是测量光束轮廓的最佳选择。可以选择EBT3，PinPoint和EDGE进行深度剂量测量，而EBT3适合进行表面剂量估计。