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[目的]探讨调强放疗(intensity-modulated radiotherapy,IMRT)技术对鼻咽癌患者吞咽功能保护的剂量学优势。[方法]收集T_(1~4)N_(2~3)M_0鼻咽癌患者90例,分成常规调强组(r IMRT)、保护吞咽结构的调强组(p IMRT)和二维常规放疗组(2D-RT),每组30例。其中p IMRT在r IMRT的基础上增加对吞咽结构咽缩肌(PC)、声带和声门上喉(包括会厌)(GSL)、食管上端(Esoph)的勾画和剂量限定。比较吞咽结构在三组放疗计划中的剂量学差异及相应的功能损伤。[结果]p IMRT计划中吞咽结构PC的平均剂量D_(mean)、V_(40)、V_(50)、V_(60)分别为4743.77±261.50c Gy、10.05%±3.59%、4.05%±2.49%、1.60%±1.45%,明显好于r IMRT和2D-RT(P<0.05),同样GSL的平均剂量D_(mean)、V_(40)、V_(50)、V_(60)分别3643.58±1822.48c Gy、6.37%±5.35%、0.45%±0.77%、0.02%±0.07%,也优于r IMRT和2D-RT(P<0.05),但是对于食管上端的受照剂量,2DRT计划的各项参数占优势(P<0.05);对于功能损伤,p IMRT组中重度损伤较少,其次是r IMRT,2D-RT组多数出现中重度损伤。[结论 ]p IMRT对吞咽结构的保护有一定的剂量学优势,为进一步研究吞咽结构的受照剂量与吞咽困难发病率的相关性提供有力的研究基础。
[Objective] To investigate the dosimetric advantages of intensity-modulated radiotherapy (IMRT) for the protection of swallowing function in patients with nasopharyngeal carcinoma. [Methods] 90 patients with T_ (1 ~ 4) N_ (2 ~ 3) M_0 nasopharyngeal carcinoma were divided into two groups: control group (r IMRT), p ⅠMRT group and two-dimensional conventional radiotherapy Group (2D-RT), 30 cases in each group. Among them, p IMRT increased the contouring and dose limitation of pharyngosinus (PC), vocal cord and supraglottic plexus (GSL) and esophus on the basis of r IMRT. Differences in dosimetry and corresponding functional impairment of swallowing structures in the three groups of radiotherapy plans were compared. [Results] The average dose of PC of swallowing structure in p IMRT plan was: D_ (mean), V_ (40), V_ (50) and V_ (60) were 4743.77 ± 261.50c Gy, 10.05% ± 3.59% and 4.05% ± 2.49 %, 1.60% ± 1.45% respectively, which were significantly better than those of r IMRT and 2D-RT (P <0.05). Similarly, the mean doses of GSL, V 40, V 50 and V 60 were 3643.58 ± 1822.48cGy, 6.37% ± 5.35%, 0.45% ± 0.77% and 0.02% ± 0.07%, respectively, but also better than r IMRT and 2D-RT (P <0.05) (P <0.05). For functional impairment, severe injury was less in p IMRT group, followed by r IMRT, most of which were moderate to severe injury in 2D-RT group. [Conclusion] p IMRT has some dosimetric advantages for the protection of swallowing structure, and provides a strong foundation for further study on the correlation between the dose of swallowing structure and the incidence of dysphagia.