Reproducibility of proliferation measurements by standardized uptake value of [18F]-fluoro-3'-deoxy-3'-L-fluorothymidine positron emission tomography (PET) in patients with lung cancer

498 Objectives: [18F] -fluoro-3’-deoxy-3’-L-fluorothymidine (FLT) has been developed as a proliferation tracer. The purpose of this study was to evaluate the reproducibility of serial FLT-PET to define objective criteria for the evaluation of treatment-induced changes. Methods: Twelve patients (8 women, and 4 men; age 59 ±9 yrs) with untreated advanced non small cell lung cancer underwent FLT-PET twice within 2 days. Using a PET-CT scanner, images of chest field were acquired at 1 hr after intravenous injection of FLT. We measured maximal standardized uptake value (SUVmax) for a malignant lung lesion with highest uptake, mean standardized uptake value (SUVmean) of T-spine bone marrow using a threshold (75% of SUVmax) defined volume of interest (VOI), and SUVmean for liver and heart blood pool using a fixed VOI. The reproducibility of SUVs was evaluated by mean and standard deviation of the difference between two tests, mean percentage difference, variability (coefficient of variation; CV) and reliability (intraclass correlation = ρ) on a patient by patient basis. Results: The mean SUVmax of lung cancer lesion from two tests was not different significantly (Table, p