磁共振弥散加权成像和PET/CT在鼻咽癌调强放射治疗中的应用

Application of Diffusion-weighted MR Imaging (DWI-MRI) and ^(18)F-FDG PET/CT to Intensity Modulated Radiotherapy (IMRT) for Nasopharyngeal Carcinoma

[目的]探讨磁共振弥散加权扫描(DWI-MRI)和18F-氟代脱氧葡萄糖PET/CT在鼻咽癌调强放射治疗中的临床价值。[方法]2007年8月至2008年2月14例初治鼻咽癌患者全部采用调强放射治疗,放射治疗前1周内和放射治疗50Gy时行DWI-MRI和PET/CT检查,观察标准摄取最大值(SUVmax)值和表观弥散系数平均值(ADCmean)。[结果]与调强放射治疗前比较,治疗中(50Gy)的SUVmax值明显下降,而ADCmean值明显上升。放射治疗前的SUVmax值和ADCmean值呈显著性负相关。在DWI序列上勾画的肿瘤靶区在普通序列如T2WI上会发生明显漂移。[结论]在初治鼻咽癌调强放射治疗中DWI-MRI与PET/CT有相似的临床价值,但DWI-MRI不能够通过融合直接参与靶区勾画。

[Purpose] To evaluate the role of diffusion-weighted MR imaging （DWI-MRI） and ^18F-FDG PET/CT in intensity modulated radiotherapy （IMRT） for nasopharyngeal carcinoma （NPC）. [Methods] Fourteen patients with NPC underwent IMRT from August 2007 to Februal7 2008. DWI-MRIs and ^18F- FDG PET/CTs were carried out at pre-radiotherapy and during IMRT at accumulative dose of 50Gy. Standard uptake value （SUVmax） and mean tumor apparent diffusion coefficient （ADCmean） were recorded. [Results] The SUVmax in IMRT at accumulative showed a significant decrease, but ADCmean showed a significant increase. There was a significant negative correlation between SUVmax and ADCmean before IMRT. The tumor areas contoured on DWI-MRIs shifted on T2WI-MRI. [Conclusion] DWI-MRI has a similar clinical value tool compared with PET/CT in IMRT. However, DWI-MRI can not be directly used in contouring of nasopharyngeal carcinoma for image shift.