摘要
目的:分析鼻咽癌患者放疗中各区域摆位误差情况,探讨胸部体表标记减小下颈摆位误差的有效性.方法:22例患者随机分成常规无胸部体表摆位标记组(无标记组),有胸部体表摆位标记组(有标记组),并在第1、6、12、18、24、30次治疗开始前执行锥形束CT扫描,分别应用骨密度配准鼻咽肿瘤区、上颈区、下颈区,相关样本的Wilcoxon 符号秩检验3个区域的摆位误差差异.应用Mann-Whitney U检验分析2组患者下颈摆位误差组间差异.最后应用van Herk公式计算2组患者各区域需要的PTV外扩.结果:无标记组前后方向3个解剖位置间差异有统计学意义(P＜0.05),进出方向下颈与鼻咽肿瘤区、上颈差异有统计学意义(P＜0.05);有标记组前后方向鼻咽肿瘤区与上颈、下颈差异有统计学意义(P＜0.05),进出方向3个解剖位置间差异有统计学意义(P＜0.05).2组间上、下颈前后方向差异有统计学意义(P＜0.05),鼻咽肿瘤区进出方向差异有统计学意义(P＜0.05).无标记组与有标记组鼻咽肿瘤区、上颈、下颈前后、进出、左右方向需要的PTV外扩分别为0.37、0.3、0.19,0.21、0.32、0.28,0.57、0.32、0.59 cm vs 0.12、0.28、0.13,0.23、0.27、0.27,0.52、0.35、0.35 cm.结论:鼻咽肿瘤区与上颈、下颈的摆位误差不尽相同,需要给予不同的PTV外扩.在患者胸部建立摆位体表标记可减少下颈左右方向的PTV外扩.
Abstract
Objective:To analyze the setup errors of each area in radiotherapy of nasopharyngeal carcinoma patients,and to explore the effectiveness of chest body surface markers in reducing the lower neck setup errors.Methods:Twenty-two patients were randomly divided into two groups:without chest surface positioning markers(unmarked group)and with chest surface positioning markers(marked group).Cone beam CT(CBCT)scanning was performed before the 1st,6th,12th,18th,24th and 30th treatments in the two groups.The nasopharyngeal tumor area,upper neck area and lower neck area were registered by bone density method,and the difference of three regions used the Wilcoxon signed rank test for the relevant samples.Mann-Whitney U test was used to analyze whether there was any difference in lower neck setup errors between the two groups.Finally,van Herk formula was used to calculate the PTV expansion required in each area of the two groups.Results:In unmarked group,there were significant differences among the three anatomical positions in the vertical direction(P＜0.05),and there were significant differences between the lower neck and the nasopharyngeal tumor area and the upper neck in the longitudinal direction(P＜0.05).In marked group,there were significant differences between the nasopharyngeal tumor area and the upper and lower neck in vertical direction(P＜0.05),and there were significant differences among the three anatomical locations in longitudinal direction(P＜0.05).There were significant differences in vertical direction of upper and lower neck between the two groups(P＜0.05),and there were significant differences in longitudinal direction of nasopharyngeal tumor area between the two groups(P＜0.05).The required vertical,longitudinal,lateral directions PTV expansion in the nasopharyngeal tumor area,upper neck,lower neck of unmarked group and marked group were(0.37,0.3,0.19;0.21,0.32,0.28;0.57,0.32,0.59 cm)vs(0.12,0.28,0.13;0.23,0.27,0.27;0.52,0.35,0.35 cm).Conclusion:The setup errors is different of nasopharyngeal tumor area,upper neck and lower neck,it should be given different PTV.The surface markers on the patient's chest can reduce the lateral direction of PTV expansion in the lower neck.
基金项目
赣州市科技局科技计划项目(GZ2018ZSF020)
维普
万方数据