功能神经外科的选择:OUR-XGD旋转式伽玛刀放射生物学效应(英文)

Choice of functional neurosurgery:radiobiological effects of OUR-XGD rotating gamma knife

背景:伽玛刀是立体定向放射外科的有效手段之一,为使靶区之外的健康组织损伤最小,对照射剂量和准直器大小的选择很有必要。目的:验证国产OUR-XGD旋转式伽玛刀的安全性和准确性,探讨其放射生物学效应。设计:完全随机设计。地点和对象:实验地点:解放军海军总医院澳海伽玛刀立体定向放射治疗研究中心。选用健康家犬10只,按准直器大小的不同随机分为3组。干预:对右额脑实质进行旋转式伽玛刀不同剂量照射,直径4mm组:90Gy2只,120Gy2只,150Gy2只,180Gy2只;直径8mm组:120Gy1只;直径14mm组:100Gy1只。观察其不同准直器、不同剂量、不同时间的放射生物学效应。主要观察指标:照射后定期观察动物行为学、MR影像学及不同时间的病理学变化。结果:不同大小准直器和不同剂量照射后于不同时间内在MR影像上出现坏死病灶,直径4mm120Gy、直径4mm150Gy和直径14mm100Gy组于照射后3个月出现毁损病灶(7.5mm×7.5mm×8.0mm,8.0mm×8.0mm×9.0mm,33.0mm×32.0mm×34.0mm),而直径4mm180Gy和直径8mm120Gy组于照射后1个月显示毁损病灶出现。病理学证实坏死灶边缘较清晰锐利,周围一定范围内的脑组织有不同程度水肿改变。结论:OUR-XGD旋转式伽玛刀具有良好的安全性、准确性和放射生物学效应;

BACKGROUND:Gamma knife is one of the effective approaches in Stereotactic Radiosurgery.It is very necessary to select the radiation dose and collimator size for minimizing the damage to healthy tissues outside the target areas. OBJECTIVE:To validate the safety and accuracy of OUR XGD Rotating Gamma Knife as well as its radiobiological effects. DESIGN: A randomized controlled trial. SETTING and PARTICIPANTS:The study was conducted in the Auhai Gamma Knife Stereotactic Radiotherapy Center of the General Navy Hospital of PLA.10 healthy canines were selected and randomly allocated into 3 groups according to the size of the collimator. INTERVENTIONS:The brain tissues of right frontal lobe were radiated by OUR XGD Rotating Gamma Knife with different radiation doses.4 mm diameter group: 90 Gy×2 canines,120 Gy×2 canines,150 Gy ×2 canines, and 180 Gy×2 canines; 8 mm diameter group: 120 Gy×1 canine,and 14 mm diameter group:100 Gy×1 canine.The radiobiological effects at different time with different dose and different size of the collimator were observed. MAIN OUTCOME MEASURES:The behaviors of the animals,MRI and the pathological changes over time were observed periodically after radiation. RESULTS:The necrotic lesions were appeared on MRI at different time with different size of collimator and different radiation dose.Necrotic lesions appeared at 3 months after radiation in groups of 4 mm diameter 120 Gy,4 mm diameter 150 Gy and 14 mm diameter 100 Gy(7.5 mm×7.5 mm ×8.0 mm,8.0 mm×8.0 mm×9.0 mm,and 33.0 mm×32.0 mm×34.0 mm respectively),while the necrotic lesions appeared at 1 month after radiation in groups of 4 mm diameter 180 Gy and 8 mm diameter 120 Gy.The pathological examination proved that the coagulated necrotic lesions had relative clear and sharp zone and edema was found in the brain tissue around the necrotic lesions in certain range as well. CONCLUSION:OUR XGD Rotating Gamma Knife has favorable safety,accuracy and radiobiological effects.The extent of tissue injury after radiation by Gamma knife significantly relates with the size of collimator,and moreover,a dosage dependent relationship obviously exists,which provides an experimental basis for the dose selection in the treatment of functional neurosurgical diseases.