（18）F-fluorodeoxyglucose positron emission tomography in the diagnosis of small pancreatic cancer

AIM：To investigate the role of 18 F-fluorodeoxyglucose positron emission tomography（FDG-PET） in the diagnosis of small pancreatic cancer. METHODS：This study involved 31 patients with proven invasive ductal cancer of the pancreas.The patients were divided into 3 groups according to the maximum diameter of the tumor：TS1（maximum tumor size≤2.0 cm） ,TS2（2.0 cm and≤4.0 cm） or TS3-4（4.0 cm） .The relationships between the TS and various diagnostic tools,including FDG-PET with dual time point evaluation,were analyzed. RESULTS：The tumors ranged from 1.3 to 11.0 cm in diameter.Thirty of the 31 patients（97%） had a positive FDG-PET study.There were 5 patients classified as TS1,15 as TS2 and 11 as TS3-4.The sensitivity of FDG-PET,computed tomography（CT） and magnetic resonanceimaging（MRI） were 100%,40%,0%in TS1,93%,93%,89%in TS2 and 100%,100%,100%in TS3-4. The sensitivity of FDG-PET was significantly higher in comparison to CT and MRI in patients with TS1（P 0.032） .The mean standardized uptake values（SUVs） did not show a significant difference in relation to the TS（TS1：5.8±4.5,TS2：5.7±2.2,TS3-4：8.2±3.9） ,respectively.All the TS1 tumors（from 13 to 20 mm） showed higher SUVs in FDG-PET with dual time point evaluation in the delayed phase compared with the early phase,which suggested the lesions were malignant. CONCLUSION：These results indicate that FDG-PET with dual time point evaluation is a useful modality for the detection of small pancreatic cancers with a diameter of less than 20 mm.