Tehran University of Medical Sciences Frontiers in Biomedical Technologies 2345-5837 0 0 2025 05 13 1091 1091 Naghmeh Firouzi Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Ali Asghar Parach IRCM - Institut de Recherche en Cancérologie de Montpellier, INSERM U1194 – ICM, France. Kaveh Tanha Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran. Mohammad Rostami Faculty of Psychology, Tarbiat Modarres University, Tehran, Iran Parham Geramifar Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran 2024 08 22 2025 02 04 Purpose In epilepsy pre-surgical evaluations, semi-automated quantitative analysis of 18F-FDG brain PET images is a valuable adjunct to visual assessment for localizing seizure onset zones. This study investigates how adjusting image reconstruction parameters can enhance the accuracy of these quantitative results. Materials and Methods A total of 234 reconstruction parameters were applied to 18F-FDG brain PET images of a focal epilepsy patient. The parameters encompassed the 3D-Ordered-Subset Expectation Maximization image reconstruction method with resolution recovery (HD) and without (non-HD), various numbers of iterations and subsets (#it×sub), pixel sizes, and Gaussian filters. The accuracy errors were determined using the relative difference percentage (RD%) in measured SUVmax and the absolute Z-scores compared to reference values derived from the normal database reconstruction set serving as the benchmark. Results The study revealed that reconstructed images with 5mm or 8mm Full width at half maximum (FWHM) Gaussian filters yielded RD% values above 5% for SUVmax and Z-scores, indicating potential inaccuracy with higher values of post-smoothing filters. The recommended reconstruction sets with RD% values below 5% for both HD and non-HD images were those with a 3mm FWHM Gaussian filter and higher (#it×sub), specifically (5×21, 8×21), (5×21, 6×21), and (7×21, 8×21) for pixel sizes of 1.01 mm, 1.35 mm, and 2.03 mm, respectively. Conclusions The findings underscore the significant impact of altering the image reconstruction sets on the SUVmax and Z-scores. Furthermore, the inconsistent fluctuations of Z-scores emphasize the importance of using standard image reconstruction sets to ensure accurate and reliable quantitative outcomes in epilepsy pre-surgical evaluations. https://fbt.tums.ac.ir/index.php/fbt/article/view/1091 https://fbt.tums.ac.ir/index.php/fbt/article/download/1091/502