近距离照射犬胆管粘膜急性放射性损伤的研究

Acute radiation injury on canine biliary mucosa by^(192)Ir-brachytherapy introduced through a metal stent.

目的 寻找动物胆管金属内支架植入方法 ,观察支架内近距离照射的胆管急性放射性损伤。方法 实验动物为体重 17～ 2 2kg的实验用雄性杂种犬。照射方法及条件 :麻醉下经手术植入胆管金属内支架 ,将1 92 Ir施源器放入支架内并给予 5～ 5 0Gy不同剂量的照射 ,1周后取胆管标本行放射损伤的评价。结果 1 92 Ir不同剂量照射后光镜下可见的胆管损伤 :照射 5Gy ,在胆管HE染色片上 ,光镜下可观察到粘膜损伤 ,10Gy时放射性损伤达肌层 ,5 0Gy时出现胆管穿孔。根据不同剂量照射后胆管的急性放射性损伤的剂量效应曲线 ,得出ED5 0 为 19.5Gy。结论 可以证实大动物的实验 ,在方法上可以更接近于临床 ,并且以上实验方法是可行的和实用的。胆管金属支架内近距离治疗有明显的剂量效应关系。

Objective To assess the acute radiation injury of dog bile duct mucosa by 192 Ir brachytherapy introduced through a metal stent.Methods Hybrid dogs weighing from 20～25 ?kg were used.Method of irradiation and experimental condition: A metal stent was implanted into the common bile duct under anaesthesia. A brachytherapy applicator was ,then,introduced into the stent and radiation by 192 Ir, at 5～50?Gy,respectively. Results Radiation injury on the biliary duct mucosa was observed at dose of 5 Gy, the damage proceeded to the musclular layer at 10 Gy. Perforation of the bile duct was observed at 50?Gy. In the dose response curve of acute radiation injury at different doses of intra biliary metal stent 192 Ir brachytherapy showed the effective dose (ED 50 ) to be 19.5 Gy.Conclusions It is shown that the method of introducing 192 Ir brachytherapy through a metal stent as carried out in the big animals, is acceptable and similar to the clinical condition. There is an obvious dose response relationship in the metal stent brachytherapy. Fractionation and late injuries need further studies.