摘要
用经验公式按合适的几何模型作剂量学计算 ,可以得到对应于不同的几何形状和不同放射源活度的等剂量曲线。用LiF热释光片在水 -有机玻璃体模及空气中 ,分别作12 5I眼科巩膜敷贴器的表面剂量测定 ,结果在误差范围内无明显区别 ,得到的最终表面剂量及其均匀性分别为 :( 3.4 6± 0 .0 1)、( 0 .178± 0 .15)nGy h·Bq。用BaF2 闪烁探测器及LiF热释光片分别作敷贴器正面、背面等的计数测量和剂量测定 ,得到12 5I巩膜敷贴器的剂量的空间分布 ,其中 ,背面剂量不到正面剂量的 0 .1%。用LiF热释光片在水 -有机玻璃人体模型中作沿着眼睛中心轴的深度剂量分布的实验测量结果表明 ,测量距离大于约 5mm以后 ,计算值与实验值在误差范围内完全符合 ;在距离小于约 5mm时 ,计算值明显高于实验值 。
Isodose curves for 125 I ophthalmic application in different geometry and activity can be obtained using the empirical formula based on suitable geometric model. The results of surface dose rate determined with lithium fluoride (LiF) thermoluminescent dosimeter (TLD's) chips in water-organic glass phantom and air had no obvious difference and the surface dose rate and its uniformity, (3.46±0.011) and (0.178±0.15)nGy/h·10 7Bq were obtained. Count measurements and dose determinations for the front and back etc. of the ophthalmic applicator with BaF 2 scintillation detector and LiF TLD's had revealed the space distribution of dose for 125 I ophthalmic applicator in which dose on the back was less than 0.1% of that on the front. The distribution of the absorbed dose rate along the eye axis had been measured using LiF TLD's in water-organic glass phantom. The measured and calculated dose data indicated that when measuring distances were larger than about 5mm the experimental results agreed with those from calculation within the range of error, otherwise the measured values were lower, still it could be explained by experimental conditions.
出处
《核技术》
CAS
CSCD
北大核心
2001年第5期393-397,共5页
Nuclear Techniques
