Estimation of uncertainties in stopping-power ratios using Monte Carlo methods

✍ Scribed by P. Andreo; A. Fransson

• Publisher: Elsevier Science
• Year: 1992
• Weight: 182 KB
• Volume: 43
• Category: Article
• ISSN: 0883-2889
• DOI: 10.1016/0883-2889(92)90021-6

✦ Synopsis

In a recent article Rogers (1991) has analyzed the numerical procedure used by Andreo and Fransson (1989) to estimate uncertainties of stopping-power ratios for ionization chamber dosimetry. The paper under discussion was an attempt to perform a numerical analysis of the uncertainties in stopping-power ratios, which previously had not been estimated using statistical methods. Approximations involved in the Spencer-Attix cavity theory and Bethe stopping-power theory were pointed out as additional contributions to the final uncertainty of stopping-power ratios, stressing the difficulty in their evaluation. The same analytical method has been used further by Andreo (1990a,b), who took into account the information available in ICRU Report 37 (ICRU, 1984b) to analyze the influence of the different procedures used to determine the densityeffect correction in electron stopping-powers on existing stopping-power ratios for dosimetry.

Although Rogers (1991) stated that "any uncertainty in the collision stopping-power is likely to show up as an uncertainty in the calculated stopping-power ratios of roughly the same magnitude, contrary to the analysis of Andreo and Fransson", a detailed consideration of the term