Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany.
Phys Med Biol. 2012 Oct 7;57(19):6245-68. doi: 10.1088/0031-9155/57/19/6245. Epub 2012 Sep 14.
For medium energy x-rays produced with tube voltages from 70 to 280 kV, the absorbed dose to water, D(w), has been determined by means of water calorimetry with relative standard uncertainties ranging from 0.45% to 0.98% at 280 and 70 kV. The results were confirmed by Monte Carlo calculations, in which the ratios of D(w) at 5 cm depth in a reference water phantom to the air kerma free in air, K(a), at the same point in space were compared to the corresponding ratios determined experimentally. The general agreement between measurement and calculation was better than 1%. These results confirm earlier investigations in which the absorbed dose to graphite was determined by means of a graphite extrapolation chamber. For the Monte Carlo calculations, an attempt was made to present a complete uncertainty budget, taking into account type B contributions also.
对于管电压为 70 至 280 kV 产生的中等能量 X 射线，通过水热量计测量了水中的吸收剂量 D(w)，在 280 和 70 kV 时，其相对标准不确定度的范围为 0.45%至 0.98%。这些结果通过蒙特卡罗计算得到了证实，其中在参考水中的一个 5 厘米深处的 D(w)与同一空间点处的自由空气中的空气比释动能 K(a)的比值与实验确定的相应比值进行了比较。测量值和计算值之间的总体一致性优于 1%。这些结果证实了早些时候的研究，其中通过石墨扩展腔确定了石墨的吸收剂量。对于蒙特卡罗计算，尝试提出一个完整的不确定度预算，同时也考虑了 B 类贡献。
