Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.
Characterization of MOSFET dosimeters for low-dose measurements in maxillofacial anthropomorphic phantoms.
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DOI：
10.1120/jacmp.v16i4.5433
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发表时间：
2015-07-08
影响因子：
2.1
通讯作者：
Kortesniemi M
中科院分区：
文献类型：
--
作者：
Koivisto JH;Wolff JE;Kiljunen T;Schulze D;Kortesniemi M
本研究的目的是表征增强型金属氧化物半导体场效应晶体管（MOSFET）剂量计，以评估测量不确定度、具有可接受准确度的单次暴露低剂量限值以及达到热释光剂量计相应限值所需的暴露次数。第二个目的是表征MOSFET剂量计对两种牙科光子能量范围、剂量依赖性、剂量率依赖性和累积剂量依赖性的灵敏度。另一个目的是使用牙颌面CBCT设备在拟人化体模头部中比较MOSFET与TLD的性能。通过暴露20个MOSFET和Barracuda MPD参考剂量计来评估不确定度。MOSFET剂量计的灵敏度进行了评估，两个光子能量范围（50-90 kVp）使用恒定剂量和聚甲基丙烯酸甲酯背散射材料。在暴露于临床CBCT方案的拟人化体模上进行MOSFET和MOSFET比较点剂量测量。MOSFET单次暴露低剂量限值（25%不确定性）为1.69 mGy。需要平均8次MOSFET暴露，以达到相应的100 Gy（0.3 mGy）低剂量限值。灵敏度与使用的光子能量无关。MOSFET剂量计不存在剂量或剂量率灵敏度，但是，对于8300 mV和17500 mV之间的累积阈值电压，每1000 mV灵敏度降低1%。在拟人体模中，MOSFET的点剂量范围为0.24 mGy至2.29 mGy，TLD的点剂量范围为0.25 mGy至2.09 mGy。平均差异为-8%。MOSFET剂量计的能量依赖性在统计上微不足道。通过对多次暴露进行平均，MOSFET剂量计可以达到与人体相当的低剂量限值，并构成使用拟人模型进行诊断剂量测定的可行方法。然而，对于单次体内测量（），灵敏度太低。PACS编号：87.50.wj
The aims of this study were to characterize reinforced metal‐oxide‐semiconductor field‐effect transistor (MOSFET) dosimeters to assess the measurement uncertainty, single exposure low‐dose limit with acceptable accuracy, and the number of exposures required to attain the corresponding limit of the thermoluminescent dosimeters (TLD). The second aim was to characterize MOSFET dosimeter sensitivities for two dental photon energy ranges, dose dependency, dose rate dependency, and accumulated dose dependency. A further aim was to compare the performance of MOSFETs with those of TLDs in an anthropomorphic phantom head using a dentomaxillofacial CBCT device. The uncertainty was assessed by exposing 20 MOSFETs and a Barracuda MPD reference dosimeter. The MOSFET dosimeter sensitivities were evaluated for two photon energy ranges (50–90 kVp) using a constant dose and polymethylmethacrylate backscatter material. MOSFET and TLD comparative point‐dose measurements were performed on an anthropomorphic phantom that was exposed with a clinical CBCT protocol. The MOSFET single exposure low dose limit (25% uncertainty, ) was 1.69 mGy. An averaging of eight MOSFET exposures was required to attain the corresponding TLD (0.3 mGy) low‐dose limit. The sensitivity was independently of the photon energy used. The MOSFET dosimeters did not present dose or dose rate sensitivity but, however, presented a 1% decrease of sensitivity per 1000 mV for accumulated threshold voltages between 8300 mV and 17500 mV. The point doses in an anthropomorphic phantom ranged for MOSFETs between 0.24 mGy and 2.29 mGy and for TLDs between 0.25 and 2.09 mGy, respectively. The mean difference was −8%. The MOSFET dosimeters presented statistically insignificant energy dependency. By averaging multiple exposures, the MOSFET dosimeters can achieve a TLD‐comparable low‐dose limit and constitute a feasible method for diagnostic dosimetry using anthropomorphic phantoms. However, for single in vivo measurements () the sensitivity is too low. PACS number: 87.50.wj
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影响因子：
3.5
作者：
Ehringfeld, C;Schmid, S;Georg, D
通讯作者：
Georg, D
影响因子：
1.6
作者：
Dong, SL;Chu, TC;Lee, JS
通讯作者：
Lee, JS
影响因子：
2.3
作者：
Lee, Ryan;Thomas, Karen E.;Gordon, Christopher L.
通讯作者：
Gordon, Christopher L.
影响因子：
2.6
作者：
Roberts, J. A.;Drage, N. A.;Thomas, D. W.
通讯作者：
Thomas, D. W.
DOI：
10.1016/j.oooo.2012.06.003
发表时间：
2012-09-01
影响因子：
2.9
作者：
Koivisto, J.;Kiljunen, T.;Kortesniemi, M.
通讯作者：
Kortesniemi, M.