Objective To evaluate the role of dual phase scan combine high resolution computerized tomography(HRCT)by ¹⁸F-FDG PET-CT imaging in the diagnosis of solitary pulmonary nodule(SPN).

Methods 173 patients with SPN demonstrated by CT, All these patients underwent dual time point combine HRCT ¹⁸F-FDG PET/CT imaging.The imaging protocol included the early imaging combine HRCT of PETCT at 50-60 min and delayed imaging of PET at 2-2.5 h post injection ¹⁸F-FDG.The standardized uptake value(SUV)was calculated for both time points.All results were expressed as the percentage change in SUV. According to characteristic in focal morphology by HRCT found, general inspection and diagnosis were benign or malignant, It was compared the result and following up result.

Results Histopathology demonstrated or following up result 41 patients with malignant lesions and 132 patients with benign lesions.The SUV of malignant lesions was SUV 6.26±0.72 in early imaging, ,and 6.88±0.74 in delayed imaging.The retention index of malignant lesions was(42.50±3.87)%.The SUV of benign lesions was 2.84±0.41 in early imaging, and 2.73±0.36 in delayed imaging.The retention index of benign lesions was(26.90±7.23)%.

Conslusions ¹⁸F-FDG PET-CT dual time point imaging combine HRCT is a simple practical method and accurate ratio high for the diagnosis of SPN.The method will be widely clinically practised.