γ刀治疗精度自测方法探讨

摘要

目的 利用自行设计的水模体模拟头部γ刀治疗全过程,探讨自测γ刀治疗精度的必要性和可行性.方法 在对γ刀的机械精度进行确认后,通过水模体获取CT和MRI图像后制定治疗计划.采用胶片感光法获得焦斑在x、y、z轴上落点,对本院及其他5家医院γ刀的治疗精度进行检测.结果 除本院CT外,6家医院其他10台CT、MRI定位的γ刀治疗精度均未达到偏差＜0.5mm的厂家技术参数要求,偏差主要表现在y轴上.按偏差值对治疗计划的坐标做相应修正后,焦斑落点的偏差均能控制在0.5 mm内.结论 模拟γ刀治疗全过程对其最终治疗精度进行检测是必要和可行的,对偏差可通过坐标修正以保证个案治疗精度,并为厂家系统修正提供参照和依据.%Objective To study the feasibility of measuring the accuracy of whole process of the head γknife treatment by the self-designed water phantom.Methods To make the treatment plan on the CT and MRI images of the water phantom and get the coordinates of exposed spots at x,y,z axis through the film frame with a view to detectingγ knife treatment accuracy in our hospital and the other five hospitals.Results Except localization by the computed tomography of our hospital,the accuracy ofγ knife treatment with localization by the imaging equipments (CT or MRI) in other hospitals all fail to get the technical request that the deviation is supposed to be within 0.5 mm.Deviation is mainly at y axis.After the correction of treatment plan parameters according to the deviation,we can make the deviation within 0.5 mm,thus we can ensure the accuracy of γ knife treatment.Conclusions It is necessary and feasible for our hospital to detect and correct the errors on the accuracy of γknife treatment.The existing deviation can be diminished through the correction of treatment plan parameters to ensure the accuracy of case treatment and to provide reference and evidence for manufactures.