体位固定方式和BMI对胸部肿瘤放疗摆位误差的影响

目的探讨胸部肿瘤患者接受放疗时,体位固定方式和身体质量指数(Body Mass Index,BMI)对摆位误差的影响。方法回顾性分析接受调强放疗的132例胸部肿瘤患者的临床资料。根据放疗时患者双手摆放位置的不同分为A、B两组,A组患者(82例)双手十指交叉置于专用臂托上,B组患者(50例)双手置于身体两侧。根据患者的BMI分为1组(偏瘦)、2组(正常)和3组(超重)。首次治疗前行CBCT扫描,使用自动骨性配准结合手动微调,计算出x、y和z轴方向的摆位误差。比较不同体位固定方式和不同BMI的摆位差异。结果B组患者x方向摆位误差小于A组(P<0.05);B3组患者x方向摆位误差小于A3组(P<0.05)。在y和z方向上,A组和B组之间的差异均无统计学意义(P>0.05)。结论胸部肿瘤患者放疗时,患者双手摆放位置对摆位误差有影响,采用双手体侧位固定方式引起的摆位误差较小。患者BMI越大,摆位误差差异越明显,超重患者更宜选用双手体侧位固定方式。

Effects of Body Posture Fixation Technique and BMI on Setup Errors of Radiotherapy for Chest Tumor

Objective To investigate the effects of posture fixation and body mass index(BMI)on setup errors in radiotherapy for patients with chest tumors.Methods The clinical data of 132 patients with chest tumor who received IMRT were analyzed retrospectively.According to the different positions of the patients’hands during radiotherapy,they were divided into two groups:patients in group A(82 cases)with their hands interlocked on the special arm rest,and patients in group B(50 cases)with their hands placed on both sides of their bodies.Patients in the two groups were divided into 1 group(underweight),2 group(normal)and 3 group(overweight)according to their BMI.CBCT scanning was performed before the first treatment,and the setup errors of x,y and z axes were calculated using automatic bone registration combined with manual fine-tuning.The positioning differences of different body posture fixation methods and BMI were compared.Results In x derection,the setup error of group B was less than that of group A(P<0.05),and the setup error of patients in B3 group was less than that in A3 group(P<0.05).In y and z direction,there was no significant difference between group A and group B.(P>0.05).Conclusion During radiotherapy of patients with chest tumor,the position of their hands has an effect on the setup error,and the setup error caused by the side position fixation of their hands is small.The higher the BMI of the patients,the more obvious the difference in setup errors.The hands fixed on body sides is more appropriate for overweight patients.