锥形束CT在肿瘤放射治疗中的作用

The Role of CBCT in Tumor Radiotherapy

目的探讨锥形束CT(cone beam,CT)在肿瘤放射治疗中的作用。方法对236例放疗患者,应用CBCT对摆位误差进行测量。对未在允许误差范围内的患者进行重新摆位,使其误差在允许范围内。将患者首次摆位误差记为Ⅰ组,重新摆位后的误差记为Ⅱ组,并对两组数据进行统计学分析。结果对数据比较分析发现,首次测量中有180例(76.3%)在允许误差范围内;48例(20.3%)未在允许误差范围内,需要重新摆位;8例(3.4%)出现不同原因的摆位错误。通过对未在允许误差范围内的48例患者进行重新摆位后,均使其误差控制在允许范围内,且重新摆位后各部位的摆位误差Ⅱ组均小于Ⅰ组。结论在肿瘤放疗中,应用CBCT对摆位误差进行测量,不仅能发现每位患者体位是否准确,且能及时发现治疗操作中的错误,而且为临床对PTV外放提供参考数据。

Objective To investigate the role of CBCT in tumor radiotherapy.Methods CBCT was used to measure the set-up error during the radiotherapy in 236 patients with malignant tumors.The patients were re-positioned if the set-up error exceeded the pre-set ranges.The set-up errors during the first measurement were named group Ⅰ,and those after re-positioning were group Ⅱ.The difference of the two groups was analyzed.Results In 180（76.3%） cases,the setup errors of the first measurement were within the pre-set range,and 48（20.3%） cases needed repositioning 8 cases had various setup-errors.After re-positioning of the 48 patients,the set-up errors were all within the permitted range,and the set-up errors in group Ⅱ were smaller than that in group Ⅰin all patients.Conclusion CBCT can measure the set-up error during radiotherapy and provide basis for the determination of the margins from CTV to PTV.