@article {Halim250, author = {Fatin Halim and Hizwan Yahya and Khairul Nizam Jaafar and Syahir Mansor}, title = {Accuracy Assessment of SUV Measurements in SPECT/CT: A~Phantom Study}, volume = {49}, number = {3}, pages = {250--255}, year = {2021}, doi = {10.2967/jnmt.120.259168}, publisher = {Society of Nuclear Medicine}, abstract = {Advances in iterative image reconstruction enable absolute quantification of SPECT/CT studies by incorporating compensations for collimator{\textendash}detector response, attenuation, and scatter. This study aimed to assess the quantitative accuracy of SPECT/CT based on different levels of 99mTc activity (low/high) using different SUV metrics (SUVmean, SUVmax, SUV0.6 max, and SUV0.75 max [the average values that include pixels greater than 60\% and 75\% of the SUVmax in the volume of interest, respectively]). Methods: A Jaszczak phantom equipped with 6 fillable spheres was set up with low and high activity ratios of 1:4 and 1:10 (background-to-sphere) on background activities of 10 and 60 kBq/mL, respectively. The fixed-size volume of interest based on the diameter of each sphere was drawn on SPECT images using various metrics for SUV quantification purposes. Results: The convergence of activity concentration was dependent on the number of iterations and application of postfiltering. For the background-to-sphere ratio of 1:10 with a low background activity concentration, the SUVmean metric showed an underestimation of about 38\% from the actual SUV, and SUVmax exhibited an overestimation of about 24\% for the largest sphere diameter. Meanwhile, bias reductions of as much as -6\% and -7\% for SUV0.6 max and SUV0.75 max, respectively, were observed. SUVmax gave a more accurate reading than the others, although points that exceeded the actual value were detected. At 1:4 and 1:10 background activity of 10 kBq/mL, a low activity concentration attained a value close to the actual ratio. Use of 2 iterations and 10 subsets without postfiltering gave the most accurate values for reconstruction and the best image overall. Conclusion: SUVmax is the best metric in a high- or low-contrast-ratio phantom with at least 2 iterations, 10 subsets, and no postfiltering.}, issn = {0091-4916}, URL = {https://tech.snmjournals.org/content/49/3/250}, eprint = {https://tech.snmjournals.org/content/49/3/250.full.pdf}, journal = {Journal of Nuclear Medicine Technology} }