RapidArc技术应用于早期鼻腔NK/T细胞淋巴瘤调强放疗的剂量学研究

Dosimetric Study of RapidArc for Early-stage Nasal Natural Killer/T-cell Lymphoma

目的:研究RapidArc技术应用于早期鼻腔NK/T细胞淋巴瘤调强放疗的剂量学特性。方法:选取10例早期鼻腔NK/T细胞淋巴瘤患者,在其CT模拟定位图像勾画靶区及危及器官,分别设计3D-CRT计划和RapidArc计划,以3D-CRT计划为参考,评估RapidArc计划计划靶体积(PTV)及危及器官的剂量学参数。结果:2种治疗计划均能满足处方剂量要求,与3D-CRT计划相比,RapidArc计划PTV的最大剂量(Dmax)减小5.49 Gy(t=12.784,P=0.000)、平均剂量(Dmean)减小1.32 Gy(t=8.416,P=0.000)、适形指数CI90%变好(t=12.805,P=0.000)、适形指数CI95%变好(t=10.138,P=0.000)、均匀指数HI变好(t=7.817,P=0.000);左视神经Dmean增加4.94 Gy(t=-2.494,P=0.034),右视神经Dmean增加7.79 Gy(t=-3.031,P=0.014),左眼Dmax减少5.83 Gy(t=4.470,P=0.002),右眼Dmax减少6.43 Gy(t=4.756,P=0.001),左腮腺Dmax减少7.69 Gy(t=3.076,P=0.013),右腮腺Dmax减少6.93 Gy(t=2.478,P=0.035)。结论:早期鼻腔NK/T细胞淋巴瘤患者采用RapidArc技术可获得优于3D-CRT计划的靶区剂量分布,同时更好的保护了部分危及器官,其疗效还需进一步临床评估。

0bjective：A treatment planning study was carried out to evaluate the performance of the novel volumetric modulated arc radiotherapy （VMAT） with RapidArc on early-stage nasal natural killer/T-cell lymphoma patients. Methods：CT images of 10 patients with early-stage nasal natural killer/T-cell lymphoma cancer were transferred into Eclipse planning system. 3D-CRT and RapidArc plans were optimized on an Eclipse treatment planning system using beam data generated for Varian IX linear ac- celerator. Planning target volume （PTV） and organs at risk were evaluated with dose-volume histogram. Results：All plans met the needs of the prescribed doses, Compared with the 3D-CRT plans, the Dax of PTV of RapidArc plan decreased 5.49 Gy （t=12.784,P=0.000）, the Dmean ofPTV decreased 1.32 Gy （t=8.416,P=0.000）, CI90% CI95% and HI became better（t=12.805,10.138, 7.817,P=0.000, 0.000, 0.000）;the Dmean of left optic nerve increased 4.94 Gy（t=-2.494, P=-0.034）, the Dean of right optic nerve in- creased 7.79 Gy （t=-3.031, P=0.014）, the Dmax of left eye decreased 5.83 Gy （t=4.470, P=0.002）, the Dax of right eye decreased 6.43 Gy （t=4.756,P=-0.001）, the Dmax, of left parotid gland decreased 7.69 Gy （t=3.076,P=-0.013）, the Dax of right parotid gland decreased 6.93 Gy （t=2.478,P=-0.035）. Conclnsions：Compared with the 3D-CRT technology, early-stage nasal natural killer/T-cell lymphoma Patients with RapidArc technology can get superior dose distribution and decrease the dose for organ at risk, the efficacy needs further clinical evaluation.