摘要
目的研究125I籽源离体照射的细胞平面剂量分布,建立125I籽源离体照射细胞平面剂量率参考模式表。方法实验应用TLD元件,测量了单粒表面活度为10.323 MBq的6711型125I籽源在水介质中点P的剂量率,并按照理论公式,计算点P的剂量率理论值,与实验测量值相互验证。然后,测量125I籽源在1 mm厚聚苯乙烯+水介质中对点P的剂量率,与水介质组的测量结果进行差别和无差别检验。模拟设计9粒125I籽源离体照射细胞装置,建立125I籽源离体照射细胞剂量率参考模式表。结果单粒125I籽源在水介质中对点P的剂量率理论计算值为0.347 cGy/h,与实验测量值(0.359±0.023)cGy/h(n=10)的差异<10%1。25I籽源在1 mm厚聚苯乙烯+水介质中对点P的剂量率测量值(n=10)为(0.350±0.027)cGy/h,与水介质中的剂量率测量值无差别。应用理论公式分析125 I籽源离体照射装置对细胞平面的剂量率分布,建立了125I籽源照射离体细胞剂量率参考模式表。结论实验结果证实1 mm厚聚苯乙烯材料对125I籽源在水介质中的剂量率分布无影响。建立的125I籽源照射离体细胞剂量率参考模式表,有推广应用价值,为今后进行125I籽源照射的离体实验时选择合理的照射模式奠定了基础。
Objective To study the dose rate distribution on cultured cell plane and establish a reference dose rate table of in vitro cell line ^125Ⅰ seed irradiator. Methods Thermolumineseence dosimetry （TLD） was used to measure the irradiation dose rate of a single 6711 model ^125Ⅰ seed with apparent activity of 10.323 MBq in water at point P. Meanwhile, the theoretic value of the irradiation dose rate at point P was calculated with theoretic formula. The difference between the calculated and observed values within 10% was set as standard to analyze the accuracy of the measurement. The irradiation dose rate of a single 6711 model ^125Ⅰ seed was measured in 1 mm thick polystyrene ＋ water medium at point P. The value was applied to differential or non-differential proof along with the value from water medium to study the effect of 1 mm thick polystyrene on distribution of irradiation dose in water. Finally, by simulating the ^125Ⅰ seed plane irradiator with nine ^125Ⅰ seeds, the distribution table of irradiation dose rate on the cultured cell plane was calculated with theoretical formula. Results The observed value （n = 10） of irradiation dose rate with one ^125Ⅰ seed in water at point P was（0.359 ±0.023） cGy/h and the calculated value was 0.347 cGy/h, the difference was within 10%. The observed value （n = 10） of irradiation dose of one 125I seed in 1 mm-thick polystyrene ＋ water medium at point P was （0.350±0.027） eGy/h, which showed no statistical difference from the observed value in water under differential and non-differential proof. The reference table on dose rate distribution for cells exposed to ^125Ⅰ seed irradiation in vitro was developed. Conclusions 1 mm-thiek polystyrene gives no significant effect on in＇adiation dose rate distribution from ^125Ⅰ seeds in water. A reference table on the dose rate distribution for cells exposed to ^125Ⅰ seed irradiation in vitro has been developed, which can be used to determine an optimal irradiating strategy for future work.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2005年第5期435-438,共4页
Chinese Journal of Radiation Oncology
