一种基于光学体表监测技术的新型摆位方法在头部放疗中的应用

目的提出一种基于光学体表监测技术的新型摆位方法,并对比分析其在头部放疗中与传统摆位方法的差异。方法通过图像引导配准结果回顾性分析2018年5月至2019年4月北京大学肿瘤医院放疗科99例头部肿瘤患者358次摆位数据,其中传统摆位方法130次(41例),新型摆位方法228次(58例)。对比摆位误差分布情况、异常摆位个数、摆位时间等指标评估新型摆位法的优势。结果新型摆位方法3个线性方向即升降(Vrt)、头脚(Lng)、左右(Lat)摆位误差绝对化后分别为(0.07±0.07)、(0.08±0.06)、(0.06±0.06)cm,3个旋转方向即偏转角(Rtn)、俯仰角(Pitch)、翻滚角(Roll)摆位误差绝对化后分别为(0.53±0.41)°、(0.59±0.44)°、(0.59±0.46)°。其摆位精度相对于传统方法组均有不同程度的改善,且差异均具有显著的统计学意义(t=3.24~6.10,P<0.001)。同时,新型摆位方法与传统摆位方法比较,异常摆位次数大幅降低,差异具有显著的统计学意义(χ^2=60.66,P<0.001),且摆位时间有所降低,但差异无统计学意义(P>0.05)。结论基于光学体表监测技术的新型摆位方法有效提高了头部肿瘤放疗患者的摆位精度,显著缩小了6自由度床修正范围,大幅度降低了异常摆位概率,提示在头部放疗中具有潜在的临床获益。

Application of a new method for patient positioning based on optical surface monitoring technology to head radiotherapy

Objective To develop a new method to set up patients using optical surface monitoring system and to compare it with the conventional method in head radiotherapy.Methods A total of 358 set-ups(130 with the conventional method and 228 with the new method),which were from 99 head tumor patients in Beijing Cancer Hospital treated between May 2018 to April 2019,obtained by using Image Guided Radiotherapy were retrospectively analyzed.The distributions of set-up errors,the number of abnormal positions,and the set-up time were compared to evaluate the potential advantages of the new method.Results The mean(±standard deviation)absolute values of setup errors of the new method were(0.07±0.07),(0.08±0.06)and(0.06±0.06)cm for the vertical,lateral,and longitudinal,(0.53±0.41)°,(0.59±0.44)°and(0.59±0.46)°for the rotation,pitch and roll,respectively.In the new method,the setup accuracy was improved(t=3.24-6.10,P<0.001)and the number of abnormal positions was greatly reduced(χ^2=60.66,P<0.001).Compared with the conventional method,the patient setup time was slightly reduced by the new method,but the difference was not statistically significant(P>0.05).Conclusions The new high-precision method to set up patients using optical surface monitoring system improves the accuracy of patients′position,decreases the corrections applied by 6DoF couch,reduces the probability of abnormal positions,and suggests the potential benefit in head radiotherapy.