Saponjski, Jelena (57207943674)Jelena (57207943674)SaponjskiMacut, Djuro (35557111400)Djuro (35557111400)MacutSaranovic, Dragana Sobic (57202567582)Dragana Sobic (57202567582)SaranovicRadovic, Branislava (57189356247)Branislava (57189356247)RadovicArtiko, Vera (55887737000)Vera (55887737000)Artiko2025-06-122025-06-122020https://doi.org/10.2478/raon-2020-0069https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099927978&doi=10.2478%2fraon-2020-0069&partnerID=40&md5=bc6e7949f227321df2a94dfee579557ahttps://remedy.med.bg.ac.rs/handle/123456789/4618The aim of the study was evaluation of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography with computed tomography (PET/CT) in the detection of active disease in the patients with suspected recurrence of the medullary thyroid carcinoma (MTC). 18F-FDG PET/CT investigation was performed in 67 patients, investigated from 2010 to 2019. _ Follow up was performed from 6 to 116 months after surgery (median 16.5 months, x± SD = 29±28.9 months). Twenty five of 67 patients underwent 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy, 11 underwent somatostatin receptor scintigraphy (SRS) with 99mTc-HYNIC TOC while 11 123I-metaiodobenzylguanidine (MIBG) scintigraphy. From 67 patients, 35 (52.2%) had true positive 18F-FDG PET/CT findings (TP). Average maximal standardized uptake value (SUVmax) for all TP lesions was 5.01+3.6. In 25 (37.3%) patients findings were true negative (TN). Four (6%) patients had false positive (FP) findings while three (4.5%) were false negative (FN). Thus, sensitivity of the 18F-FDG PET/ CT was 92.11%, specificity 86.21%, positive predictive value 89.74%, negative predictive value 89.29% and accuracy 89.55%. In 27 patients (40%) 18F-FDG PET/CT finding influenced further management of the patient. 18F-FDG PET/CT has high accuracy in the detection of metastases/recurrences of MTC in patients after thyroidectomy as well as in evaluation and the appropriate choice of the therapy. © 2021 2021 Jelena Saponjski, Djuro Macut, Dragana Sobic Saranovic, Branislava Radovic, Vera Artiko, published by Sciendo.¹⁸F-FDG PET/CTfollow upmedullary thyroid carcinomapostoperative