Preliminary Study On Radiation-induced Brain Injury In Rats By Using Magnetic Resonance Imaging

Objective: To study gamma knife radiosurgery (Gamma knife) after irradiation of ratcaudate nucleus imaging findings of radiation injury and cytological changes．Material and methods：10adult male Wistar rats were were enrolled into the study.Five rats served as controlled group while the other five rats underwent Gamma knife.The right caudate-putamen nucleus was selected as the target of irradiation. A8mmcollimator was used to transmit50Gy to the target region. Four weeks and12weeksafter irradiation in rats were treated with1.5T MRI axis unenhanced and enhancedscan,and take brain tissue after HE staining cytological changes．Results：1. Rats12weeks after radiotherapy reduced appetite, activity slightly reduced, the haircolor difference and different degrees of hair removal. Experimental group ratsreceived Gamma Knife treatment before weighing370.6±14.5g after receivingGamma Knife treatment for12weeks weighing313.8±17.5g, t=0.2767, P <0.01,the difference was statistically significant, weight decreased. The control group ofrats before radiotherapy weight of372.5±12.5g, weighing396.9±15.6g afterradiotherapy. Compared with the experimental group received, the difference inweight was significantly (P <0.01).2. After4weeks, the rats underwent brain MRI examinations showed the irradiatedarea was slightly increased signal lesions and surrounding tissue edema. At12weeks, the experimental rats T2WI visible exposed target flaky slightly highersignal, ill-defined, near the lateral ventricle pressure, enhanced the TIWI exposed target was obvious enhancement, but inhomogeneous enhancement. MRI images ofrats in the control group were no obvious abnormalities.3. The experimental group rat brain tissue sections and HE staining cerebral corticalneurons pyknosis obvious nucleoli, accompanied by glial cell hyperplasia, edema,and a small amount of lymphocytic infiltration.Conclusion MRI can well shows the change in the radiation-induced brain injury, theradioactive brain damage caused by the diagnosis of gamma knife have importantclinical significance.