RT Journal Article SR Electronic T1 Influence of different blood glucose levels on SUVmax calculation in normal and neoplastic tissues using dual-time-point 18FDG PET-CT imaging protocol JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 166 OP 166 VO 61 IS supplement 1 A1 Kandeel, Ahmed A1 Mamoun, Marwa A1 Hussein, Elshaymaa A1 Alhusseini, Maha YR 2020 UL http://jnm.snmjournals.org/content/61/supplement_1/166.abstract AB 166Background: Multiple biological and procedural factors can influence the accuracy of standardized uptake values (SUVs); one of the more important patient parameters is the blood glucose level, which has been shown to inversely-linearly affect SUVs, because non labeled glucose is competitive with FDG uptake. Use of dual time point imaging (DTPI) in selective cases can potentially improve diagnostic accuracy and interpretation confidence in FDG PET imaging since the time delay between injection of FDG and the acquisition of images greatly affects the extent of FDG uptake and its clearance. Objective: To assess the impact of various blood glucose levels (BGLs) on18F-FDG uptake values as measured with SUVmax in normal organ tissues as well as in neoplastic lesions compared in both early and delayed images. Methods: Our prospective study was done on 200 patients who were referred for clinical PET/CT examinations for various oncological indications. Dual-time imaging were performed for all patients. SUVmax was obtained within apparently normal regions in multiple specified organs and the main pathological lesion in axial PET/CT images taking in consideration not to involve areas with abnormal 18F-FDG uptake or artifacts such as brown fat, focal muscle uptake, focal atherosclerotic disease...etc. The values were compared within various blood glucose patients’ groups in the early and delayed axial PET/CT images. Patients were divided according to BGL into; Group A: included 134 patients (67%) with BGL < 80 to 120 mg/dl. Group B: included 38 patients (19%) with BGL > 120 to 150 mg/dl. Group C: included 28 patients (14%) with BGL > 150 mg/dl. Results: Significantly higher SUVmax values were found in the late images compared to the early images in the myocardium and bone marrow (all groups; p value <0.001), Muscles (all groups: group A; p value 0.009, group B; p value 0.012 and group C; p value 0.028), brain (group A; p value <0.01), tonsils (group A; p value <0.001 and group C; p value 0.008), spleen (group B; p value 0.002). Significantly higher SUVmax values were found in the early images compared to the late images in the lungs (group A; p value <0.001 and group B; p value 0.021), Mediastinal blood pool (all groups; p value <0.001), Fat (all groups: group A; p value 0.011, group B; p value 0.002 and group C; p value 0.024), and liver (group A; p value <0.001 and group B; p value 0.003). Significantly higher SUVmax values were found in the late images compared to the early images in malignant tissues in all BGL; group A; p value 0.001, group B; p value 0.022 and group C; p value 0.002. Conclusion: Selective use of dual time point imaging (DTPI) can potentially improve diagnostic accuracy and interpretation confidence in 18FDG PET-CT imaging, however in both study sets; SUV calculation in normal and malignant tissues can be potentially affected by the changes in BGL.