Dose rate distribution on cultured cell exposed to ~(125)I seed in vitro irradiation / 中华放射肿瘤学杂志

ABSTRACT

Objective To study the dose rate distribution on cultured cell plane and establish a reference dose rate table of in vitro cell line ~(125)I seed irradiator.Methods Thermoluminescence dosimetry(TLD) was used to measure the irradiation dose rate of a single 6711 model(~(125) I) 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(~(125) I) seed was measured in 1mm-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(~(125) I) seed plane irradiator with nine(~(125) I) 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(~(125) I) seed in water at point P was(0.359?0.023)cGy/h and the calculated value was 0.347cGy/h,the difference was within 10%.The observed value(n=10) of irradiation dose of one(~(125) I) seed in 1mm-thick polystyrene + water medium at point P was (0.350?0.027)cGy/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(~(125) I) seed irradiation in vitro was developed.Conclusions 1mm-thick polystyrene gives no significant effect on irradiation dose rate distribution from(~(125) I) seeds in water.A reference table on the dose rate distribution for cells exposed to(~(125) I) seed irradiation in vitro has been developed,which can be used to determine an optimal irradiating strategy for future work.