单次大剂量照射活体动物脑的放射区域代谢和超微结构的研究  

Single-fraction High-dose Brain Irradiation:Experimental MR Spectroscopy and Metabolism Study in Vivo

作　　者：官键[1] 陈龙华[1] 李志勇[2] 

机构地区：[1]南方医科大学南方医院放疗科,广东广州510515 [2]南方医科大学南方医院神经外科,广东广州510515

出　　处：《实用放射学杂志》2007年第1期115-118,共4页Journal of Practical Radiology

基　　金：国家自然科学基金项目(39870225)。

摘　　要：目的通过质子磁共振波谱分析(magneticresonancespectroscopy,MRS)单次大剂量照射后脑照射区域内的代谢和超微结构变化,为放射性脑损伤发生机理的研究提供分子生物学水平上的实验研究资料和理论基础。方法将40只家兔随机分为4组,分别给予单次大剂量10、15、20Gy和30Gy照射,建立放射性脑损伤家兔实验动物模型,通过测量照射前后动物乳酸(Lacticacid,Lac)、N-乙酰天门冬氨酸(N-acetylaspartate,NAA)、胆碱(Choline,Cho)、肌酸(Creatine,Cr)等的波峰变化及照射不同时期内受照区域脑组织超微结构变化情况,比较照射前后不同时期各波峰变化情况并行统计学分析。结果在放射性脑损伤发生早期,质子MRS即有轻度降低,至电镜下出现明显的神经细胞水肿坏死时,质子MRS波谱分析已经有明显统计学意义的变化。结论质子MRS分析可以较好地反映超微结构的变化。Objective To analyse the ultrastructural and metabolic changes of brain injury after single - fraction high - dose radiation in rabbits by means of proton （1 -hydrogen） magnetic resonance spectroscopy （IH MRS） ,in order to provide the basic theory for early detection of radiation - induced brain injury. Methods Experimental model of single - fraction high - dose radiation - injured brain was established in 40 rabbits , which were randomly divided into 4 groups and underwent 10, 15, 20 Gy and 30 Gy radiation , respectively. Proton MRS in a clinical MR imager was used to ascertain the amount of whole - brain N - acetylaspartic acid （NAA） , lactic acid （Lac） , choline （Cho） , ereatine （Cr） before and within 8 weeks after focused single - fraction high - dose irradiation therapy. Metabolic maps of NAA, Lac, Cho and Cr were created from MRS data set. Detection of irradiation injury among the tested models was assessed by receiver operating characteristic analysis and by quantitative signal intensity changes. The peak values of NAA , Lac , Cho and Cr on MRS before and after radiation were measured. Histopathology and electron microscope were used to ascertain changes of the ultrastructural organization in the irradiated area. the results were compared and statisti - cally analyzed. Results Initially MRS was found a slightly decrease. Until obviously change was detected, statistical significance variation of MRS occurred. A significant decrease in 1 H MRS occurred at the early stage of brain injury induced by single - fraction high - dose irradiation. Conclusion ^1H MRS may be regarded as a noninvasive and sensitive means for the detection of early radiation - induced brain injury.

关 键 词：放射性脑损伤 磁共振波谱分析 超微结构 

分 类 号：R818[医药卫生—放射医学] R816.1[医药卫生—临床医学]