Ambiger T Y, Iyer P S
Strahlentherapie. 1980 Mar;156(3):192-7.
Time dose fractionation schemes in radiotherapy have been developed on empirical lines over a period of several years. Ellis proposed the NSD formula to facilitate a meaningful comparison of clinical results from different centres and different fractionation regimes. Recent studies indicate that there is a steep tumour dose response curve which necessitates that the delivered doses must have an accuracy within +/- 5%. The ranges of the variations of the parameters in the NSD formula which still give dose estimates within this accuracy have been studied in this paper. It is concluded that because of the uncertainties involved in dose output calibration and other physical and empirical constants, extreme caution has to be exercised in routinely using the NSD concept and those of TDF, CRE, PT and BIR, which have the NSD concept as their basis.
放射治疗中的时间剂量分割方案是在数年时间里根据经验制定的。埃利斯提出了NSD公式，以便对来自不同中心和不同分割方案的临床结果进行有意义的比较。最近的研究表明，存在一条陡峭的肿瘤剂量反应曲线，这就要求所给予的剂量必须在±5%的精度范围内。本文研究了NSD公式中参数变化的范围，在此精度范围内仍能给出剂量估计值。得出的结论是，由于剂量输出校准以及其他物理和经验常数存在不确定性，在常规使用NSD概念以及以NSD概念为基础的TDF、CRE、PT和BIR等概念时必须极其谨慎。
