高能X线照射犬脑后的反应、形态及CT变化

Morphologic changes, reaction and computed tomographic images following canine hemibrain irradiated with megavolt x-ray

目的：犬脑照射后，观察不同时期的反应，病理及CT的变化，为CT诊断放射性脑坏死提供新的依据．方法：用SL75－14型直线加速器对犬脑行外照射，建立犬脑放射性损伤模型．结果：早期病理所见血管周围性水肿，细胞凝固性坏死系射线直接损伤脑组织，脱髓鞘与少突胶质细胞坏死有关，CT显示为低密度区；放射性脑坏死在CT显示为增强效应的包块，坏死区出血和炎细胞浸润是放射性脑坏死的特征，可作为与脑瘤复发的鉴别点．结论：照射侧的脑室扩大是由脑萎缩引起的，而不是颅压升高所致ICT能反映放射性脑损伤的程度．

AIM: Megavolt radiation has been provided to be an effective weapon in the treatment of tumour. While radiation may cause injury or necrosis of brain tissue,irradiated canine brain were taken for pathologic examinations at differentintervals. The experiment reported here provided some new evidence in diagnosing radiation brain necrosis by using CT.METHODS: Each animal was irradiated with SL75-14 type 8 MV lineae accelerator. The reaction of animals, morphologicchanges and CT images were observed. RESULTS: The low density areas showed by CT should corresponds to the earlyperiod perivascular edema, coagulation necrosis of nerve cells and demyelination which is related to necrosis of oligodendrocyte. Hemorrhage and inflammation in the necrotic area arecharacteristic of the de'layed necrosis differing from tumor recurrence. CONCLUSION: Postirradiation dilatation of the lateral ventricular might be the result of atropic changes.rather than the increase of intracranial pressure do not play important role. CT changes can reflect degree of radiationbrain injury.