鼻咽癌调强放疗靶区剂量学研究及近期疗效观察

Dosimetric Analysis of Intensity Modulated Radiation Therapy in Nasopharyngeal Carcinoma

目的:分析鼻咽癌调强放疗和常规放疗中靶区和周围组织器官的剂量分布,观察鼻咽癌调强放疗的效果和副作用。方法:对63例初治鼻咽癌采用CT模拟定位,为每例患者制定2套放疗计划,即调强放疗计划和半开准直器常规放疗计划。63例患者非随机分为2组,调强组28例进行调强放射治疗,常规组35例进行常规放射治疗。结果:在IMRT和常规计划中,对肿瘤区(GTV)的靶区覆盖率(V95)分别为99.55%和98.41%,差异无显著性(P>0.05);对于临床靶区(CTV1)的靶区覆盖率(V95)分别为98.51%和87.26%,差异有显著性(P<0.05);颈淋巴结靶区的靶区(CTV2)覆盖率(V95)分别为98.71%和77.63%,差异有显著性(P<0.05),临床靶区(CTV1)和颈淋巴结靶区(CTV2)IMRT的V95优于常规放疗。对串联器官IMRT计划和常规计划均能比较好的保护脊髓、脑干和视交叉,对并联器官IMRT计划中腮腺和下颌骨受照剂量显著低于常规计划。调强组与常规组近期有效率分别为96.4%和97.1%,差异无显著性(P>0.05),放疗6个月后调强组口干症状明显轻于常规组。结论:调强放疗可以使各个靶区得到足够、均匀的剂量分布,周围正常组织得到较好的保护。

Objective： To analysis the dosimetric characteristic on target and surrounding organs and observe efficiency and toxicities in intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC）. Methods： 63 primary NPC cases were selected. IMRT and conventional plans were made for each of them. 63 cases were unrandomized to IMRT group and conventional group, 28 cases of IMRT group were treated with IMRT plans, 35 cases of conventional group were treated with conventional plans. Results： In IMRT plan and conventional plan, the dose coverage rates of V95 of the gross tumor volume （GTV） were 99.55% and 98.41%, there was not significantly difference （P〉 0.05）; those of the clinical target volume （CTV1） were 98.51% and 87.26%, there was significantly difference （P 〈 0.05）; that of the neck lymph nodes target voltune （CTV1） were 98.71% and 77.63%, there was significantly difference （P 〈0.05）, the IMRT plan had satisfied dose coverage of the clinical target volume （CTV1） and neck lymph nodes target volume （CTV2） when compared with conventional plan. The both IMRT plan and conventional plan could protect spinal cord, brain stem and optic chiasm for normal tissues of the series connection, the IMRT plan could better protect parotid gland and mandible for normal tissues of the parallel connection. The complete response rates were 96.4% and 97.1% in IMRT group and conventional group, there was not significantly difference （P〉0.05）, but the xerostomia of IMRT group was significantly improved after that the radiotherapy was end for 6 mouths when compared with that of conventional group. Conclusion： IMRT may yield enough and uniformity dose to every target volume, protect surrounding normal tissue.