Zheng Xiao-Kang, Chen Long-Hua, Wang Quan-Shi, Wu Hu-Bing, Wang Hong-Mei, Chen Yong-Qin, Yan Wei-Pin, Li Qi-Sheng, Xu Yi-Kai
Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou, People's Republic of China.
Int J Radiat Oncol Biol Phys. 2007 Dec 1;69(5):1381-8. doi: 10.1016/j.ijrobp.2007.05.033. Epub 2007 Sep 14.
Assuming F-18-fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET)/computed tomography (CT) to be more accurate in representing the true disease extent than CT alone, we prospectively designed this study to evaluate how the addition of FDG-PET influences CT-based radiotherapy planning for locally recurrent nasopharyngeal carcinoma.
All patients underwent FDG-PET/CT simulation scans. For each patient, the gross tumor volume (GTV) was separately delineated with or without the addition of PET information and defined as GTV PET/CT and GTV CT, respectively. Corresponding planning target volumes (PTV) were generated for the GTV CT (PTV(CT)) and GTV PET/CT (PTV PET/CT). Three-dimensional conformal radiotherapy plans were separately created for PTV CT and PTV PET/CT. To assess the potential geographic miss of the PET/CT-based disease in CT-based treatment planning, the size and location of the GTV PET/CT, PTV(PET/CT), and PTV(CT) were analyzed, and the three-dimensional conformal radiotherapy plans created using the PTV CT were evaluated with the GTV PET/CT and PTV PET/CT information.
A total of 43 patients were enrolled in this study. Distant metastasis was found in 4 patients with the addition of the PET information. The 39 patients without distant metastasis proceeded to three-dimensional conformal radiotherapy planning. Inadequate coverage of the GTV PET/CT and PTV PET/CT by the PTV CT occurred in 7 (18%) and 20 (51%) patients, respectively. This resulted in <95% of the GTV(PET/CT) and PTV PET/CT receiving >or=95% of the prescribed dose in 4 (10%) and 13 (33%) patients, respectively.
The addition of FDG-PET information might influence CT-based radiotherapy planning for locally recurrent nasopharyngeal carcinoma by altering the definition of the target volume, with the potential to avoid a geographic miss of true disease.
假定F-18-氟-2-脱氧-D-葡萄糖正电子发射断层扫描（FDG-PET）/计算机断层扫描（CT）在反映疾病真实范围方面比单纯CT更准确，我们前瞻性地设计了本研究，以评估添加FDG-PET如何影响基于CT的局部复发性鼻咽癌放疗计划。
所有患者均接受FDG-PET/CT模拟扫描。对于每位患者，分别在添加或不添加PET信息的情况下勾画大体肿瘤体积（GTV），分别定义为GTV PET/CT和GTV CT。为GTV CT（PTV(CT)）和GTV PET/CT（PTV PET/CT）生成相应的计划靶体积（PTV）。分别为PTV CT和PTV PET/CT创建三维适形放疗计划。为评估基于PET/CT的疾病在基于CT的治疗计划中可能出现的几何遗漏，分析了GTV PET/CT、PTV(PET/CT)和PTV(CT)的大小和位置，并使用PTV CT创建的三维适形放疗计划结合GTV PET/CT和PTV PET/CT信息进行评估。
本研究共纳入43例患者。添加PET信息后，4例患者发现远处转移。39例无远处转移的患者进行三维适形放疗计划。PTV CT对GTV PET/CT和PTV PET/CT的覆盖不足分别发生在7例（18%）和20例（51%）患者中。这导致分别有4例（10%）和13例（33%）患者的GTV(PET/CT)和PTV PET/CT中<95%的体积接受≥95%的处方剂量。
添加FDG-PET信息可能会通过改变靶体积的定义影响基于CT的局部复发性鼻咽癌放疗计划，有可能避免对真实疾病的几何遗漏。
