Ramani R, Russell S, O'Brien P
Division of Medical Physics, Toronto-Sunnybrook Regional Cancer Centre, North York, Ontario, Canada.
Int J Radiat Oncol Biol Phys. 1997 Mar 1;37(4):959-64. doi: 10.1016/s0360-3016(96)00600-1.
The use of metal oxide-silicon field effect transistors (MOSFETs) as clinical dosimeters is demonstrated for a number of patients with targets at different clinical sites.
Commercially available MOSFETs were characterized for energy response, angular dependency of response, and effect of accumulated dose on sensitivity and some inherent properties of MOSFETs. The doses determined both by thermoluminescence dosimetry (TLD) and MOSFETs in clinical situation were evaluated and compared to expected doses determined by calculation.
It was observed that a standard calibration of 0.01 Gy/mV gave MOSFET determined doses which agreed with expected doses to within 5% at the 95% confidence limit for photon beams from 6 to 25 MV and electron beams from 5 to 14 MeV. An energy-dependent variation in response of up to 28% was observed between two orientations of a MOSFET. The MOSFET doses compared very well with the doses estimated by TLDs, and the patients tolerated MOSFETs very well. A standard deviation of 3.9% between expected dose and MOSFET determined dose was observed, while for TLDs the standard deviation was 5.1%. The advantages and disadvantages of using MOSFETs for clinical dosimetry are discussed in detail.
It was concluded that MOSFETs can be used as clinical dosimeters and can be a good alternative to TLDs. However, they have limitations under certain clinical situations.
展示了金属氧化物 - 硅场效应晶体管（MOSFET）作为临床剂量计在多位不同临床部位有靶区的患者中的应用。
对市售的MOSFET进行了能量响应、响应的角度依赖性以及累积剂量对灵敏度和MOSFET一些固有特性的影响等方面的表征。评估并比较了在临床情况下通过热释光剂量测定法（TLD）和MOSFET测定的剂量与通过计算确定的预期剂量。
观察到，对于能量范围从6到25 MV的光子束和能量范围从5到14 MeV的电子束，0.01 Gy/mV的标准校准使得MOSFET测定的剂量在95%置信限内与预期剂量的偏差在5%以内。在MOSFET的两个方向之间观察到响应的能量依赖性变化高达28%。MOSFET测定的剂量与TLD估计的剂量相比非常吻合，并且患者对MOSFET的耐受性很好。观察到预期剂量与MOSFET测定剂量之间的标准偏差为3.9%，而对于TLD，标准偏差为5.1%。详细讨论了使用MOSFET进行临床剂量测定的优缺点。
得出结论，MOSFET可作为临床剂量计，并且可以是TLD的良好替代物。然而，它们在某些临床情况下存在局限性。
