RT Journal Article SR Electronic T1 The influence of time of flight (TOF) information on scatter fraction and the effect of scatter correction on 18F-PET images. JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 2105 OP 2105 VO 59 IS supplement 1 A1 Kimoto, Saki A1 Hirose, Tomoya A1 HASHIMOTO, NAOKI A1 Shoji, Ayano A1 Tsutsui, Yuji A1 Himuro, Kazuhiko A1 Baba, Shingo A1 Sasaki, Masayuki YR 2018 UL http://jnm.snmjournals.org/content/59/supplement_1/2105.abstract AB 2105Purpose: The goal of this study was to examine the influence of time of flight (TOF) information on the scatter fraction and the effect of scatter correction (SC) on 18F-PET images. Materials and Methods: The examinations were performed using a NEMA IEC PET Scatter Phantom. The line source with 18F solution was inserted into this phantom. The radioactivity concentration was 72.1 MBq/mL. The PET data were acquired 14 times using a Biograph mCT for 25 minutes each in the three-dimensional list mode. The scanner was equipped with a single scatter simulation algorithm for SC. The PET images were reconstructed using ordered subset expectation maximization (OSEM) and OSEM+TOF with and without scatter correction. A Gaussian filter was not used. The image matrix was 400×400, and the slice thickness was 5mm. Three regions of interest (ROIs) were established on PET images: ROI1 surrounding the line source for both true and scatter counts, ROI2 for the background around the line source and ROI3 for the entire phantom. The estimated percentage of scatter (%S) was calculated based on the ratios of scatter counts to the total counts of all 56 slices. Results: On the OSEM, the %S was 25.8±0.5% for SC(-) and 6.6±1.1% for SC(+). On the OSEM+TOF, the %S was 27.2±1.5% for SC(-) and 6.0±0.7% for SC(+). The %S was not markedly different between OSEM images and OSEM+TOF images irrespective of SC. Conclusions: : In conclusion, the estimated percentage of scatter on 18F-PET images were not influenced by TOF information. The effect of scatter correction was not markedly different regardless of the utilization of TOF information.