鼻腔NK/T细胞淋巴瘤常规放疗与适形调强放疗的剂量学比较

摘要

Objective To compare the dosimetry difference of three radiation therapies for patients with nasal NK/T cell lym-phoma. Methods Six patients with nasal NK/T cell lymphoma were treated by conventional radiation therapy (CRT) , three dimensional conformal radiation therapy (3 D-CRT) and intensity modulated radiation therapy (IMRT) in the same treatment planning system (TPS). The referring point should reach prescription dose (54Gy) in CRT,and the planning target volume (PTV) reach 95% of the prescription dose (54Gy) in 3D-CRT and IMRT. The difference of irradiation dose between target volume and organ at risk was compared by isodose curve and dose volume histogram ( DVH). Results The conformity index (CI) and heterogeneity index (HI) of 3D-CRT and IMRT were better than CRT. 3D-CRT and IMRT could reduce the exposure dose of brain stem and parotid gland. The coverage volume percentage of prescription doses of 3D-CRT and IMRT were better than CRT. Conclusion 3D-CRT and IMRT can increase the dose conformity and homogeneity index,and they can protect brain stem,parotid gland much better than CRT for patients with nasal NK/T cell lymphoma. IMRT has more apparently advantage.%目的 比较分析3种不同放疔技术治疗鼻腔NK/T细胞淋巴瘤的剂量学差异,为临床治疗提供依据.方法 选取6例鼻腔NK/T细胞淋巴瘤患者,应用三维治疗计划系统(TPS)分别为每例患者设计3种治疗计划,即常规放疗(CRT)、三维适形放疗(3D-CRT)和调强适形放疗(IMRT),对CRT要求参考点达到处方剂量54Gy,对3D-CRT和IMRT要求95％的等剂量线(54Gy)包括整个计划靶体积(PTV).根据等剂量曲线及剂量体积直方图(DVH)比较3种计划靶区剂量分布及危及器官(OARs)受量的差异.结果 3D-CRT及IMRT的靶区适形度指数(CI)、均匀性指数(HI)均较CRT计划好,同时减少了脑干、腮腺的受照射剂量；3D-CRT及IMRT的处方剂量覆盖靶区体积百分比高于CRT.结论 对鼻腔NK/T细胞淋巴瘤,3D-CRT及IMRT可以提高靶区的适形度和均匀度,在保护脑干、腮腺方面较CRT具有明显优势,其中IMRT优势更明显.