PET/CT引导鼻咽癌靶区勾画对危及器官剂量影响的研究

Study on the effect of PET/CT-guided nasopharyngeal carcinoma target area on the dose of endangered organs

目的:比较18F-FDG-PET/CT与CT/MRI引导鼻咽癌靶区勾画在调强放疗中危及器官放射剂量的差异。方法:选择局部晚期鼻咽癌31例患者,由18F-FDG-PET/CT引导靶区勾画作为实验组,由CT/MRI引导靶区勾画作为对照组,分别制定调强放疗计划。比较两组中大体肿瘤体积(GTV)、危及器官的剂量差异。结果:PET/CT较CT/MRI勾画的原发灶体积小,T3、T4体积比较,差异均有统计学意义(P<0.001)。PGTV在Dmin、 Dmean、 D95,实验组小于对照组;在Dmax,实验组大于对照组,差异均具有统计学意义(P<0.001)。脊髓的Dmin、Dmax实验组小于对照组,差异有统计学意义(P=0.022,0.042);Dmean,两组无差异。脑干、腮腺的Dmax实验组小于对照组,差异有统计学意义(P=0.001,0.047);Dmin、Dmean两组无差异。视交叉、颞叶的Dmin、 Dmean、Dmax两组比较,差异无统计学意义(P>0.05)。结论:PET/CT引导靶区勾画在晚期鼻咽癌患者调强放射治疗中同步加量的应用,在MRI显示的原发病灶靶区当中,使PET/CT浓聚区的病灶剂量较高,平均剂量及最小剂量较小。数据显示脊髓、脑干及腮腺所受剂量减少,对视交叉及颞叶无影响。未来要观察剂量变化对病灶控制及危及器官的长期影响。

Objective: To compare the differences between 18F-FDG-PET/CT and CT/MRI-guided nasopharyngeal carcinoma target delineation in radiation-induced doses in intensity-modulated radiotherapy. Methods: From December 2016 to December 2017, a total of 31 patients with locally advanced nasopharyngeal carcinoma underwent undergraduate treatment, and 18F-FDG-PET/CT and CT/MRI were used to guide the target area to develop an intensity-modulated radiotherapy plan(Test group and control group). The dose difference between GTV and endangered organs in the two groups was compared. Results: 1. Comparison of primary tumor volume: PET/CT was smaller than CT/MRI, and T3 and T4 volumes were significantly different(P<0.001). 2. Comparison of the two groups, PGTV in Dmin, Dmean, D95, the experimental group was smaller than the control group;in Dmax, the experimental group was larger than the control group, and there was a significant difference(P<0.001). 3. The Dmin and Dmax experimental groups of the spinal cord were smaller than the control group, showing a significant difference(P=0.022, 0.042);Dmean, no difference between the two groups. 4. The Dmax experimental group of the brainstem and parotid gland was significantly smaller than the control group(P=0.001, 0.047);there was no difference between Dmin and Dmean. There was no difference between the two groups of Dmin, Dmean and Dmax in the chiasm and temporal lobe. Conclusion: PET/CT guided target delineation is applied in the simultaneous dose adjustment of intensity-modulated radiation therapy in patients with advanced nasopharyngeal carcinoma, which makes the dose of PET/CT concentration zone higher, and the average dose and minimum dose are smaller. Reduce the dose of spinal cord, brain stem and parotid gland, no effect on the optic chiasm and temporal lobe. In the future, we should observe the long-term effects of dose changes on lesion control and endangered organs.