Original Article Molecular Imaging and Radionuclide Therapy 2014;23(1): 16-20 DOI: 10.4274/Mirt.76376

Objective: SUV max is often calculated at FDG PET examinations in systematic studies as well as at clinical examinations. Since SUV max represents a very small portion of a lesion it may be questioned how statistically reliable the figure is. This was studied by assessing the repeatability of SUV max between two FDG acquisitions acquired immediately upon each other in patients with chest lesions. Methods: In 100 clinical patients with a known chest lesion, two identical 3 min PET registrations (PET1 and PET2, respectively) were initiated within 224±31 sec of each other. The difference in SUV max between the lesion for the two PET scans (ΔSUV max) was calculated and the uncertainty expressed as the coefficient of variation, CV (%). The correlation between ΔSUV max and the lowest SUV max from PET1 or PET2, the approximate metabolic lesion volume, the time from FDG injection to PET1 and the time between PET1 and PET2, respectively, was also assessed. Results: In 56 patients SUV max increased at the second acquisition and in 44 patients it decreased. Mean of SUV max was 7.8±6.1 and 7.8±6.2 for PET1 and PET2, respectively. The mean percentage difference was 0.9±7.8. The difference was not significant (p=0.20). CV gave an uncertainty of 4.3 % between the two measurements which is a strong indicator of equivalence. There was no correlation between ΔSUV max and any of the assessed four parameters. The difference between the acquisitions, 0.9%, was much lower com-pared to the 3 previous published similar, but more restricted studies where the difference was 2.5-8.2%. Conclusion: From camera and computational perspectives, SUV max is a stable parameter Key words: Examinations and diagnoses, positron-emission tomography, fluorodeoxyglucose F18, reproducibility of results Özet Amaç: Sistematik çalışmalarda ya da klinikte yapılan muayenelerde yapılan FDG PET çalışmalarında SUV max sıklıkla hesaplanmaktadır. SUV ma