髓母细胞瘤是儿童常见的后颅凹肿瘤,来源于原始神经外胚层,多位于小脑蚓部或小脑半球部,晚期出现颅内压增高,可侵犯脑干或扩展到后颅凹外,治疗效果很差。本文就我院采用国产 ZJ-10医用直线加速器治疗髓母细胞瘤的方法作一介绍。材料与方法病员俯卧于定位床,通过模拟定位划出需保护的器官,如眼睛、口腔和鼻咽部等。用切割器制成能保护正常组织的泡沫模型,另外定做二块22.5cm×26cm 厚1cm 的有机玻璃板,制成要求能插入加速器的机头档铅槽。在有机玻璃上固定3～4只4～6cm 的螺丝。把切割的泡沫模型放在有机玻璃上,螺丝的位置在泡沫模型中间,然后将低熔点铅直接倒入,厚度10cm,制成左右二块,保护正常组织的异型铅块。脊髓野:病员俯卧于治疗床中心,胸腹部垫海绵枕,二上肢置于身体两侧,二腿伸直,二足背紧靠床面,头颅前额用沙袋固定,听眦线与床面垂直,上端包括第二颈椎上缘,下端为第二骶椎下缘。若治疗野长度不够,可通过延长源皮距的方法,经物理测量符合临床要求。全脊髓总量25～30Gy,每周5次,每次150～180CGy。头颅野:治疗脊髓野的位置固定不变,将加速器的机头旋转+-90°,全颅侧野上界超过头顶部,下界包括第一颈椎下缘,然后将固定在有机玻璃上的异型铅块插入机头挡铅槽治疗端。全颅剂量30Gy,每周5次,左右野各90CGy,照射30Gy 后缩野,后颅凹总量追加至50～54Gy。缩野前界在后床突小脑幕附着处,后界枕部,上界小脑幕顶部。下界在第一颈椎下缘。 Medulloblastoma is a common posterior fossa tumor in children, originating in the primitive neuroectoderm, mostly in the cerebellar vermis or cerebellar hemispheres, with increased intracranial pressure in the late stage, which can invade the brainstem or extend into the posterior fossa. The effect is poor. This article on our hospital using domestic ZJ-10 medical linear accelerator for the treatment of medulloblastoma for an introduction. Materials and methods The patient is prone to the positioning bed and the simulated organs are to be protected by simulated positioning such as eyes, mouth and nasopharynx. Made of a cutter to protect the normal tissue of the foam model, the other two custom-made 22.5cm × 26cm thick 1cm plexiglass plate, made of headlamps required to insert the accelerator tank. Plexiglass fixed 3 to 4 4 ~ 6cm screws. The cut foam model on the plexiglass, the location of the screw in the middle of the foam model, and then the low melting point lead directly into the thickness of 10cm, made about two blocks to protect normal tissue shaped lead. Spinal cord field: the patient prone to the center of the treatment bed, chest and abdomen pad sponge pillow, upper extremity placed on both sides of the body, legs straight, close to the bifurcation of the bed, head forehead with a sandbag fixed, listening 眦 line perpendicular to the bed , Including the upper edge of the second cervical vertebra, the lower end of the second sacral margin. If the treatment field length is not enough, by extending the source skin distance method, the physical measurement to meet the clinical requirements. The total spinal cord 25 ~ 30Gy, 5 times a week, each time 150 ~ 180CGy. Skull field: the treatment of spinal cord field fixed position, the rotation of the accelerator head + -90 °, the total cranial lateral field above the top of the head, the lower boundary, including the lower edge of the first cervical vertebra, and then fixed on the plexiglass shaped lead Insert the block head bumper treatment end. Total cranial dose 30Gy, 5 times a week, left and right 90CGy, irradiation 30Gy after the field, the total amount of posterior fossa increased to 50 ~ 54Gy. Condensation in the front of the bed after the tentorium attached to the tentacles, the occipital rear sector, the upper bound of the top of the tentorium. Lower bound at the lower edge of the first cervical vertebra.