宫颈癌术后三维适形放疗和共面等分设野调强放疗计划的对比分析

目的探讨宫颈癌术后三维适形放射治疗（3D-CRT）和共面等分设野调强放射治疗（IMRT）计划靶区及其周围危及器官受
照剂量的差异。方法随机选择10 例宫颈癌术后患者，进行CT扫描、靶区和危及器官的勾画，处方剂量50 Gy。分别进行
3D-CRT和共面等分设野IMRT计划设计，计算靶区剂量均匀度指数(HI)、适形度指数(CI)、最大受照剂量、最小受照剂量、平均受
照剂量和危及器官照射体积等并对结果进行比较分析。结果5F-IMRT、7F-IMRT和9F-IMRT在靶区适形度方面明显优于
3D-CRT；在危及器官（膀胱V30、V40、V50，小肠V50和直肠V30、V40、V50）保护方面，5F-IMRT、7F-IMRT和9F-IMRT明显优于
3D-CRT，P<0.05。而各IMRT计划之间差异无统计学意义，P>0.05。结论宫颈癌术后辅助放疗共面等分IMRT计划无论在靶
区适形度还是正常组织保护方面均优于3D-CRT，同时也证实7野或9野IMRT未必较5野获益更多。5野与7、9野的IMRT相
比,在治疗时间及费用方面有独特的优势，值得在临床上推广。

Dosimetric study of postoperative 3-dimensional conformal radiotherapy and coplanar decile intensity-modulated radiotherapy for cervical cancer

Objective To compare the difference of the dose distribution in clinical target volume and organ at risk(OAR) between coplanar decile field intensity-modulated radiotherapy(IMRT) and conventional three-dimensional conformal radiotherapy(3D-CRT) for postoperative radiotherapy of cervical cancer.Methods Ten postoperative patients with cervical cancer were selected randomly to undergo CT scan and planning target volume(PTV) and OAR contouring.3D-CRT and coplanar decile IMRT planning was performed for each patient with a prescribed dose of 50 Gy.The homogeneity index(HI),conformity index(CI),maximum dose,minimum dose,mean dose of PTV,and irradiated volume of OARs were calculated and the results were compared.Results 5-field IMRT,7-field IMRT and 9-field IMRT plans had a significant better conformity index(CI) of PTV compared with 3D-CRT(P<0.05).Compared with 3D-CRT plans,V30,V40,and V50 of the bladder,V50 of the small bowel,and V30,V40,and V50 of the rectum in the coplanar decile IMRT plans were all significantly reduced(P<0.05) but showed no significant differences among the IMRT plans(P>0.05).Conclusion Coplanar decile IMRT plans is superior to 3D-CRT plan in terms of the conformity index(CI) of the PTV and sparing the bladder,rectum and small bowel.Seven-field and 9-field IMRT do not warrant more benefits than 5-field IMRT,and the latter can significantly reduce the treatment time and costs.