摘要
目的观察高剂量率(HDR)192Ir后装照射犬外周血管、神经病理反应,为HDR后装放疗应用于骨与软组织恶性肿瘤保肢术提供放射剂量耐受阈参考。方法健康普通犬12条,常规外科手术沿犬股神经血管束放置施源器,术后经3次HDR后装放射,每种剂量1条犬,总剂量分别为15、30、45、60、75、90Gy,照射长度1.0cm,照射后10、60d活体取材,经光镜和透射电镜进行组织学观察,自身对侧血管神经束作对比。结果照射后10d,大血管主要表现为内膜病变;照射后60d,剂量达到45Gy时,出现明显的不同程度血管增生和管腔狭窄。神经照射后改变,15Gy组变化不明显;30Gy以上组变化明显:急性期出现不同程度脱髓鞘,髓鞘和轴突崩解脱失等改变;慢性期神经萎缩明显。结论HDR后装放疗引起外周血管明显病理变化的剂量为45Gy;而30Gy足以引起明显的神经病理变化。建议临床治疗控制在总剂量30Gy以下,贴近神经处酌减剂量。
Objective To investigate the response of normal dog's extremity vessel and nerve to high dose rate 192Ir source to provide pathological reference for the use of afterloading brachytherapy in limb salvage of malignant tumors.Methods Twelve dogs received routine surgical procedures.One catheter was placed along the bundle of each dog's femoral nerve and vessels.The total irradiation doses were 15 Gy,30 Gy,45 Gy,60 Gy,75 Gy and 90Gy respectively after 3 times of irradiation.Different samples of vessels and nerves were taken out on the 10th day and 60th day after radiation.The contralateral femoral nerves and vessels were used as controls.Results Microscopic examination showed that the major vessel tissue changes were acute responses of the endangium on the 10th day.The obvious proliferation and thickening of vessels and the stenosis of lumen were found on the 60th day when the irradiation dose≥45 Gy.The acute pathological responses of nerves were followed as the myelin sheath with denaturation and myelinolysis and the neurite with disaggregation in all dogs to varying degrees but one received 15 Gy.The chronic response was that the neuratrophy and rarefaction of nerve fiber were obvious when the dose was up to 30 Gy.Conclusion When the irradiation dose is up to 45 Gy,the severe lumen stenosis appears.Thirty Gray is high enough for obvious nerve response.It is suggested that the irradiation dose should be less than 30 Gy and more attention should be paid if the catheter is close straightly to nerves.
出处
《中华实验外科杂志》
CAS
CSCD
北大核心
2005年第6期738-739,i006,共3页
Chinese Journal of Experimental Surgery
