泛影葡胺阴道残端标记物对宫颈癌术后放疗剂量的影响

Effect of vaginal stump markers of diatrizoate on the dose distribution of postoperative radiotherapy for cervical cancer

探讨泛影葡胺阴道残端标记物对宫颈癌术后放疗剂量分布的影响。收集2022年7月至2023年7月甘肃省妇幼保健院/甘肃省中心医院行宫颈癌根治术后放疗且定位前放置泛影葡胺显影棉球标记阴道残端的患者12例,行容积旋转调强计划设计,得到计划PlanA,作为实际治疗计划。将被泛影葡胺显影的阴道残端区域的相对电子密度值替换为正常阴道壁的相对电子密度值,保持计划优化参数不变,重新计算得到Plan B。比较两组计划各评价指标及剂量分布的差异。结果显示:Plan B较PlanA组HI(1.048 vs.1.047)指数略差,CI(0.870 vs.0.868)指数更优;Plan B的PTV平均剂量(46.48 vs.46.47)和阴道残端剂量(47.14 vs.46.45)高于PlanA,直肠最小剂量(6.42 vs.6.49)低于PlanA。结果提示,泛影葡胺阴道残端标记物对剂量分布造成的影响可忽略不计。

This study aimed to investigate the effect of diatrizoate vaginal stump markers on the dose distribution of postoperative radiotherapy for cervical cancer.From July 2022 to July 2023,12 patients who underwent radical postoperative radiotherapy for cervical cancer at Gansu Provincial Maternity and Child-Care Hospital,Gansu Provincial Central Hospital,and who had cotton balls with meglumine diatrizoate placed to mark the vaginal stump before positioning were enlisted.Volume modulated arc therapy was designed as Plan A and was used in the actual treatment plan.The relative electron density value of the vaginal stump area marked by meglumine diatrizoate was replaced by the relative electron density value of the normal vaginal wall,and Plan B was recalculated,keeping the planning optimization parameters unchanged.The evaluation indicators and dose distributions were compared between the two group.The results showed that the Homogeneity index(HI)was slightly worse in the Plan B group than the Plan A group(1.048 vs.1.047)but the Conformance index(CI)(0.870 vs.0.868)was better in the Plan B group.The average dose to the planned target volum(46.48 vs.46.47)and the dose to the vaginal stump(47.14 vs.46.45)were higher for Plan B than Plan A,and the minimum dose to the rectum(6.42 vs.6.49)was lower for Plan B than Plan A.The effect of diatrizoate vaginal stump markers on dose distribution was negligible.