鼻咽癌调强放疗对海马结构的剂量影响分析

目的 分析鼻咽癌调强放疗中海马结构的受照剂量及相关影响因素.方法 回顾性分析59例鼻咽癌的调强放疗计划,比较不同临床分期鼻咽癌的海马结构受照剂量及特点.结果 59例鼻咽癌患者的海马结构受照剂量受T分期影响明显,Dmax11.1 ～78.2 Gy,Dmean3.2 ～44.6 Gy,T1 ～T4期海马结构受照剂量(Dmax和Dmean)差异均有统计学意义,Dmax(F=24.2,P＜0.05)、Dmean(P=16.3,P＜0.05).其中T3、T4期病例平均受照剂量和体积明显高于T1、T2期,Dmax、Dmean分别为(58.6±14.8)Gy、(20.9±19.3) Gy和(40.8±9.4) Gy、(12.5±5.1) Gy.结论 鼻咽癌调强放疗中,海马结构可能受到较大剂量的照射,肿瘤T分期是重要的影响因素,特别在T3-4期病例放疗中值得关注.

Dosimetric study of influence of intensity modulated radiotherapy for nasopharyngeal carcinoma on hippocampal formation

Objective To evaluate the dosimetric characteristics of hippocampal formation (HF) in the intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC).Methods Fifty-nine NPC patients underwent IMRT.Simultaneous integrated boost technology was used to determine the doses for the target areas. The dose ranges of the HF were collected by dose-volume histogram. The influence of T stage on the exposure doses (D_max,D_mean,D₂₀,V₁₀,V₂₀,V₃₀,and V₄₀) were compared.Results The maximum dose for the HF (D_max) ranged from 11.1 to 78.2 Gy(F=24.2,P<0.05) and the D_mean ranged from 3.2 to 44.6 Gy(F=16.3,P<0.05). The D_max and D_mean of the T_1-2 stage patients were (40.8±9.4) Gy and (12.5±5.1) Gy, respectively, both significantly lower than those of the T_3-4 stage patients (58.6±14.8) Gy, (20.9±9.3) Gy]. The mean exposed volume of the T₄ stage patients was significantly larger than that of the T₁ and T₂ stages patients.Conclusions In the IMRT of NPC, the HF receives rather high irradiation dose. T stage is the main factor influencing the dose, especially T₃ and T₄ stages deserve serious attention.