Characterization of a microSilicon diode detector for small-field photon beam dosimetry
Characterization of a microSilicon diode detector for small-field photon beam dosimetry
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DOI：
10.1093/jrr/rraa010
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发表时间：
2020-05-01
影响因子：
2
通讯作者：
Ogawa, Kazuhiko
中科院分区：
文献类型：
--
作者：
Akino, Yuichi;Fujiwara, Masateru;Ogawa, Kazuhiko
本研究通过评价TrueBeam STx和射波刀产生的光子束，表征了一种用于小野光子束剂量测定的新型非屏蔽二极管探测器microSilicon（型号60023）。通过照射光子并将水温从11.5 ℃增加到31.3 ℃来评估温度依赖性。对二极管E、微晶硅、微金刚石和艾德GE探测器的剂量线性、剂量率依赖性、能量依赖性、探测器深度-剂量（PDD）、束流剖面和探测器输出因子（OFdet）进行了评价。将微硅探测器的OFdet与其他探测器的场输出因子进行比较。尽管二极管E显示出0.26%/℃的比率的线性变化，但微晶硅显示出0.4%以内的小温度依赖性。Diode E和EDGE探测器的探测器阅读与剂量率之间呈正相关，而microSilicon探测器的响应稳定在0.11%以内。二极管E和微硅显示出与束能量的负相关性。在所有的探测器中，微硅的OFdet最小。对于5 x 5 mm（2）TrueBeam和5 mm phi射波刀光束，微硅的OFDet和微金刚石的场输出因子之间的最大差异分别为2.3%和1.6%。PDD数据在剂量下降区域显示出较小的变化。微硅和微金刚石探测器产生了类似的半影宽度，而其他探测器显示出更陡峭的半影轮廓。微硅显示出良好的特性，包括小的温度和剂量率的依赖性，以及小的空间分辨率和输出因子适合于小场剂量学。
This study characterized a new unshielded diode detector, the microSilicon (model 60023), for small-field photon beam dosimetry by evaluating the photon beams generated by a TrueBeam STx and a CyberKnife. Temperature dependence was evaluated by irradiating photons and increasing the water temperature from 11.5 to 31.3 degrees C. For Diode E, microSilicon, microDiamond and ED GE detectors, dose linearity, dose rate dependence, energy dependence, percentdepth-dose (PDD), beam profiles and detector output factor (OFdet) were evaluated. The OFdet of the microSilicon detector was compared to the field output factors of the other detectors. The microSilicon exhibited small temperature dependence within 0.4%, although the Diode E showed a linear variation with a ratio of 0.26%/degrees C. The Diode E and EDGE detectors showed positive correlations between the detector reading and dose rate, whereas the microSilicon showed a stable response within 0.11%. The Diode E and microSilicon demonstrated negative correlations with the beam energy. The OFdet of microSilicon was the smallest among all the detectors. The maximum differences between the OFdet of microSilicon and the field output factors of microDiamond were 2.3 and 1.6% for 5 x 5 mm(2) TrueBeam and 5 mm phi CyberKnife beams, respectively. The PDD data exhibited small variations in the dose fall-off region. The microSilicon and microDiamond detectors yielded similar penumbra widths, whereas the other detectors showed steeper penumbra profiles. The microSilicon demonstrated favorable characteristics including small temperature and dose rate dependence as well as the small spatial resolution and output factors suitable for small field dosimetry.