PET脑显像及其他显像技术在放射性脑损伤诊断的对比性研究

目的 探讨^18F－脱氧葡萄糖（FDG）正电子发射型计算机断层显影（PET）脑显像和其他医学影像方法对早期诊断放射性脑损伤的价值，以达到预防、减少脑放射损伤的目的。方法 静脉注射^18F-FDG后行脑显像，获得横断面、冠状面、矢状面断层显像。所有病人均进行CT检查。结果 20例正常人脑PET显像图像可见大脑皮质各叶、基底神经节、丘脑及小脑放射性分布均匀对称。12例完成头颈部恶性肿瘤放疗后有临床症状者均检出不同程度局灶性脑组织葡萄糖代谢下降，显像阳性率100％；其中10例鼻咽癌放疗后PET结果提示放射脑损伤病灶共23处，最常见于颞叶病灶13处、脑干4处、小脑4处以及顶叶2处。2例脑胶质细胞瘤放疗病人，PET结果提示病灶：顶叶2处、颞叶1处、枕叶1处。12例放疗后病人CT检查仅10例提示放射性脑损伤。结论 PET脑显像能准确、早期诊断脑放射损伤，是头颈部恶性肿瘤肿瘤放疗后的非常重要的监测手段。

The Preliminary Study in Demonstration of Cerebral Radiation Injury with 18F-FDG Brain PET Images

Objective To investigate the value of 18F-FDG brain PET in diagnosis early cerebral radiation injury. Methods The study included 20 normal subjects,12 patients finished head-neck radiotherapy.40 min after intravenous administration of 18F-FDG , brain scan was performed by the PETscanner.The transaxial,coronal,and sagittal images were then reconstructed.And the semiquantitative analysis was performed to evaluate using the ratio of mean radioactivity of cerebral lobe to cerebellum. Results In normal subjects PET scan showed clear and symmetrical images of cerebral cortex, basal ganglia, thalamus and cerebellum.All of the 12 cases with radiotherapy were demonstrated cerebral radiation injury with PET scans. The sensitivity was 100%. In the 10 cases of NPC ,PET showed 23 lesions cerebral radiation injury totally, including 13 lesions on temporal lobe,4 on brain stem,4 on cerebellum and 2 on parietal lobe. Only 10 of 12 radiotherapic patients had abnormal findings on CT scans. Conclusions It is very useful that 18F-FDG brain PET scan to detect the early cerebral radiation injury for radiotherapy patients.