Comparative study of gross tumor volume shown on MRI and FDG PET/CT of nasopharyngeal carcinoma
LIN Qin*, WU Hua, ZHU Lu-chao, FU Li-rong, DAI Ming-ming, WANG Li-chen
*Department of Radiation Oncology, First Affiliated Hospital of Xiamen University, Xiamen 361003, China Corresponding author:WU Hua, Department of Nuclear Medicine and Centro of PET in Minnan, First Affiliated Hospital of Xiamen University, Xiamen 361003, China;Email:wuhua1025@163.com
Abstract：Objective To compare gross tumor volume (GTV) of nasopharyngeal carcinoma (NPC) according to MRI and FDG PET/CT and to investigated four fixed threshold methods to delineate the GTV using FDG PET/CT. Methods Fifty patients with primary biopsy-proven NPC were prospectively were enrolled into the study. FDG PET/CT scans and MRI were carried out within one week prior to pretreatment, respectively. The GTV was named GTV-MRI (GTV were delineated according to MRI), GTV-PETvis, GTV-PET30, GTV-PET40, GTV-PET50(GTV was delineated according to the PET-based GTVs obtained by visual interpretationor, by percentage of the SUVmax(30%, 40%, 50%) thresholds, respectively). The differences were compared among the GTV-MRI, GTV-PETvis, GTV-PET30, GTV-PET40 and GTV-PET50 in different by Wilcoxon test. Results Of 50 patients, the median of volume descending order were:GTV-MRI 27.8 cm3,GTV-PETvis 22.2 cm3, GTV-PET30 22.7 cm3,GTV-PET40 14.4 cm3 and GTV-PET50 9.0 cm3. However, there was no significant difference between GTV-PETvis and GTV-PET30(Z=－0.05, P=0.958),as well as GTV-MRI and GTV-PETvis or GTV-PET30 in 25 patients who were T1－2 stage (Z=－0.93, －0.93,P=0.353,0.353), the other GTVs were all different in 50 patients′(Z=－5.74-－2.09, P=0.000－0.037). Conclusions All the GTVs delineated by the different methods of using FDG PET/CT were less than the GTV delineated by MRI. The potential advantages with the GTV-PETvis or GTV-PET30 delineated by FDG PET/CT are reduction of biological metabolic tumor volume in GTV delineation and reduction of the size of the GTV in NPC patients.
LIN Qin*,WU Hua,ZHU Lu-chao et al. Comparative study of gross tumor volume shown on MRI and FDG PET/CT of nasopharyngeal carcinoma[J]. Chinese Journal of Radiation Oncology, 2012, 21(6): 492-495.
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