摘要
目的建立放射性^125I粒子离体照射模型,研究模型中离体细胞照射平面的剂量和剂量分布。方法应用14颗粒子环形排布的照射模型,用临床上常用的6711型^125I粒子。实验前随机抽取20%的粒子校正,应用TLD元件对模型进行测量。先用37MBq的^125I粒子照射6d,测量细胞平面受照剂量并计算初始剂量率;然后用同样活度的^125I粒子照射10d后测量,与用公式计算的照射剂量值进行比较。结果TLD标定：测量读数和照射剂量拟合为线性关系。单颗粒子活度测量值与出厂标定值相差〈±5%。照射6d测量细胞平面累积剂量为1.58Gy,计算初始剂量率为0.273Gy/d;照射10d的测量值和理论计算值分别为2.43和2.57Gy,两者相差5.76%。根据对模型的测量和计算,可推导出在不同的初始剂量率下受照剂量和照射时间的关系。结论建立的放射性125I粒子离体照射模型简便实用,可用于放射生物学实验研究。受照剂量与照射时间关系的建立,为今后开展放射性125I粒子相对生物效应的研究和对肿瘤细胞作用机制的研究奠定基础。
Objective To establish the model of an iodine-125 seed irradiator in vitro and investigate the dosimetry on the treatment plane. Methods Irradiator was fabricated with 14 of ^125 I seeds with model 6711, which are commonly used in clinical treatment, and arranged in a circular array. Thermoluminescent dosemeters （TLDs） were used to measure the irradiation dose and 20% of all seeds were calibrated before irradiation. The dose on treatment plane exposed to 1 mCi was detected at day 6 post irradiation and initial dose rate was calculated. Then, irradiation was performed at day 10 under the same condition, and the results were compared between the measured value and the calculated one. Results The results of TLDs indicated that the relationship between the readings of TLD and the doses of irradiation was linear. Errors between the measured values and the calibrated ones for a single seed activity were within 4- 5 %. The dose on treatment plane measured after irradiation at day 6 was 1.58 Gy, and initial dose rate calculated was 0.273 Gy/d. The calculated and measured doses were 2.57 Gy and 2.43 Gy exposed to irradiation at day 10, respectively with variation of 5.76% . It was suggested that the relationship between irradiated dose and time at different initial dose rate were developed. Conclusious This irradiator is simple and efficient with potential usage in radiobiological experiments. The relationship between dose and time for ^125I seeds irradiation in vitro will help to study its relative biological effectiveness and to elucidate mechanism of its effect on cancer cell.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2007年第3期267-270,共4页
Chinese Journal of Radiological Medicine and Protection
基金
国家自然科学基金资助项目（30572137）
