CT引导下子宫内膜癌3 D腔内近距离治疗计划的剂量学分析

Dosimetric analysis of computed tomography guided three-dimensional intracavitray brachytherapy in endometrial carcinoma

目的：通过比较子宫内膜癌腔内近距离治疗3D计划和2D计划，探讨子宫内膜癌3D腔内近距离治疗的剂量学特性。方法回顾性分析11例子宫内膜癌患者的39次3D近距离治疗计划并重新设计2D计划，从DVH上比较靶区V150、D90，膀胱、直肠、小肠及乙状结肠D2 cm3。采用配对t检验方法分析组间差异。结果靶体积＜60 cm3时，3D、2D计划靶区D90分别为（551.17±90.33）、（574.15±117.18） cGy （P＝0.390），随着靶体积增加3D计划的D90增加（P＝0.001）。3D、2D计划靶区V150分别为（51.05±21.61）、（53.41±1.71） cm3（P＝0.482）。当靶体积＞60 cm3时，与2D计划相比，3D计划提高靶区覆盖同时增加了危及器官受量，但小肠受量增加不明显（ P＝0.128）。此外，不同计划模式下BMI增加对直肠、小肠、膀胱及乙状结肠的受量无显著影响， P值分别为0.239、0.198、0.744和0.834。结论子宫内膜癌3D腔内近距离治疗与2D计划相比可显著提高较大靶区的覆盖范围，有效控制OAR受量，临床疗效与不良反应尚需进一步观察。

Objective To study the dosimetric peculiarity of 3D intracavitary brachytherapy in the application of endometrial carcinoma comparing with traditional 2D plans. Method 39 3D brachytherapy treatment plans of 11 patients with endometrial carcinoma were retrospectively analyzed with re.planning 2D treatment plan, the dose volume histogram （ DVH） parameters such as the target dose volume parameters V150 and D90 , the 2.cc doses to organs such as bladder, small intestine, rectum and sigmoid and the total reference air kerma TRAK were analyzed. The differences between the two groups are compared by paired samples T test. Results For target with V〈60 cm3 ,there is no statistically significant difference between 2D and 3D plans,the D90 is （551.17±90.33） cGy and （574.15±117.18） cGy,respectively （P=0.390）. As the increase of target volume,the D90 came to be significantly different （ P=0.001） , high dose region V150 for 3D and 2D plans is （51.05±21.61） cm3 and （53.41±11.71） cm3, respectively （P=0.482）. With the target volume larger than 60 cm3 ,compare to 2D plans, the 3D plan can increase the target coverage as well as OAR dose except for small intestine （ P=0.128） . In addition, with different plan mode,the BMI did not affect the crisis organ dose such as rectum, small intestine, bladder and sigmoid, the P value is 0.239, 0.198,0.744 and 0.834,respectively. Conclusions For endometrial carcinoma,compared with traditional two.dimensional plans,the 3D brachytherapy treatment plans can significantly improve the target coverage and avoiding overdose of organs, clinical curative effect and side effect still needs further observation.