模拟摆位训练对鼻咽癌调强放疗首次摆位误差的影响研究

摘要

目的:研究治疗前模拟摆位训练对鼻咽癌调强放疗首次摆位误差的影响,为提高治疗摆位精度提供临床参考.方法:实验入组100例鼻咽癌调强放疗患者,随机分为常规组(50例)与训练组(50例).常规组按常规过程治疗摆位,训练组在治疗前一天进行一次模拟摆位训练.相同条件下,首次治疗摆位时利用EPID给患者拍摄MVDR验证片,通过灰度配准+人工配准得到摆位误差,并记录满足临床要求所需调整的摆位次数n.采用独立t检验进行统计分析.结果:与常规组相比,训练组中患者首次摆位的旋转误差无论在调整前还是在调整后都要明显变小,差别具有统计学意义(P<0.05).调整前和调整后的常规组与训练组的旋转角度Rtn分别为(0.25°±0.75°) vs (-0.01°±0.22°)(P=0.026)和(0.03°±0.15°) vs (-0.12°±0.10°)(P=0.027).另外,训练组在首次摆位过程中调整次数要明显少于常规组(P<0.05),调整次数分别为(0.14±0.40)次 vs (0.80±1.26)次(P=0.001).结论:鼻咽癌调强放射治疗前进行模拟摆位训练可以明显减少旋转角度误差和调整摆位次数,提高了放射治疗摆位精度和效率.%Objective:To study the influence of the first positioning error with simulation training for nasopharyngeal carcinoma intensity modulated radiation therapy(IMRT),and provide clinical reference for improving the accuracy of positioning.Methods:The data of 100 patients with nasopharyngeal carcinoma intensity-modulated radiation therapy were entered into the experiment,and divided into conventional group(50 cases) and training group(50 cases),randomly.The patients of training group were simulation positioning trained in the previous day of treatment,but the positioning was according to the conventional treatment process in conventional group.MVDR images were acquired with the EPID installed in a linear accelerator,and registered with the planning DRR using automatic gray registration software in the same conditions,and approved by a doctor.The errors of the first positioning and the times of adjustment,for meeting the clinical requirements,were recorded.Independent t test were used for statistical analysis.Results:Compared to conventional group,the errors of the first time positioning were smaller for the training group,especially for the rotation errors which have a statistically significant difference(P<0.05).The rotation errors(Rtn) of conventional group and training group in the pre-adjustment and after-adjustment were(0.25°±0.75°) vs (-0.01°±0.22°),(P=0.026) and(0.03°±0.15°) vs (-0.12°±0.10°),(P=0.027),respectively.Additional,the times of adjustment for training group were less than conventional group significantly(P< 0.05),and the times were(0.14± 0.40) vs (0.80±1.26),(P=0.001),respectively.Conclusion:The rotation errors and the times of adjustment could be reduced significantly by simulation positioning training before treatment for NPC intensity modulated radiation therapy,the precision and efficiency of radiotherapy positioning were improved.