MOSFET用作临床X射线剂量测量的研究

目的利用场效应晶体管对X射线的敏感性,探讨制作出符合临床需要、实用的X射线计量探测器的可行性。方法①确定合适的场效应晶体管工作参数,即确定工作电压VDS以及漏极电阻DR,并测量在X射线照射场效应晶体管时,漏极电阻DR上的电压降VDR,以确定场效应晶体管对X射线照射是否敏感。②任选市售不同型号的场效应晶体管若干,并在临床的标准条件下对这些场效应晶体管作X射线照射,通过测定VDR值,以确定场效应管对X射线照射反应的普遍性。③使用电离室（临床标准配置）对X射线的剂量作标定,并对处于相同X射线照射下场效应晶体管的VDR值作比对测量,以确定VDR值与X射线剂量之间的函数关系。④大剂量X射线照射试验用场效应晶体管,通过观察其对大剂量射线轰击的耐受性,以确定其作为传感器应当具有的可靠性。结果市售场效应晶体管对X射线照射的反应具有普遍性;其输出信号与X射线剂量之间具有很好的线性关系;试验用场效应管能够经受大剂量1000cGy的15MV高能X射线轰击。结论经过挑选的市售场效应晶体管完全能适用作临床上检测X射线的相对剂量。

MOSFET Used for Clinical X-ray Doses Measured Exploration

Objective In this study,we discussed the feasibility of fabricating a practical X-ray dose detector accord with clinical practice by MOSFET which were sensitive to X radiation.Methods ① Built the MOSFET working circuit,namely,by confirming the Drain Voltage —VDS,and the Drain Resistance—DR,and measuring the voltage VDR on the DR to make sure the MOSFET＇s sensitivity to X-ray.② Chose different types of MOSFET in market and irradiating on them in standard condition and measuring the VDR,to make sure whether all the MOSFET have the same radiation effects.③ With the same X-ray exposure,compare the VDR measured in MOSFET and the dose measured by ionization chamber and find out their functional relationship.④ Determining the MOSFET＇s durability by large exposure.Results The MOSFET sold in market that have same radiation effects of X-ray;the measured VDR and the measured dose was well linear correlation;the MOSFET can afford 1000 cGy X-ray exposure.Conclusion The selected MOSFET can fully used to measure the relative dose of X-ray.