ABSTRACT
Objective To investigate the interseed dose attenuation for multiple 125I seeds.Methods Monte Carlo simulation was done by Geant 4 to investigate the dose distribution of single seed and multiple seeds.The results were compared with the dose calculation method from TG43-U1 and examined by experiments.Results The difference of single seed dose distribution between Monte Carlo method and line source model was ± 3％.The difference between Monte Carlo method and experiment result was ± 5％.The interseed dose attenuation of multiple seeds at the interesting points was 3.8％ to 13.2％ and the average interseed dose attenuation was 7.2％.The difference of experiment result and Monte Carlo result was less than 6％.Conclusions The interseed attenuation is about 7％ and the maximum value may be larger than 13％ for multiple seeds.The interseed dose attenuation may be larger in tissue.So it is not accurate to calculate the dose distribution by using TG43-U1.
ABSTRACT
This study was aimed to establish a method for quality control of Tibetan medicine Shi-Wei Xiao-Shi-San (SWXSS). Thin layer chromatography (TLC) was established for the qualitative determination. Cinnamal and piperine were determined by HPLC. The separation was performed on Phenomenex C18 column (4.6 mm × 250 mm, 5μm). The results showed that TLC can be used in the identification of pomegranate seed and Terminalia chebula. The linear ranges of cinnamal and piperine were within the range of 0.06-0.37μg and 0.05-0.33μg, respectively. And the standard line was Y=9.273 2×106X-2.348 2×105, r=0.999 8;Y=7.315×103X-3.857, r=1.000 0. It was concluded that the identification method was specific, accurate and practical, which can be applied in the quality control of SWXSS.