RT Journal Article SR Electronic T1 Prediction of Response to Neoadjuvant Chemotherapy in Osteosarcoma using Dual-phase 18F-FDG PET/CT JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1460 OP 1460 VO 56 IS supplement 3 A1 Byeon, ByeongHyeon A1 Kong, Chang-Bae A1 Lim, Sang Moo YR 2015 UL http://jnm.snmjournals.org/content/56/supplement_3/1460.abstract AB 1460 Objectives We evaluated the ability of dual-phase 18F-FDG PET/CT to predict the histologic response after neoadjuvant chemotherapy (NAC) in osteosarcoma.Methods Thirty one patients with osteosarcoma treated with NAC and surgery were prospectively enrolled. After injection of 18F-FDG, both early (~60 min) and delayed (~150 min) PET were acquired before and after the completion of NAC. SUVmax, early/delayed SUVmax change (RImax), and early/delayed SUVmean change (RImean) of tumor were measured before (SUV1, RImax1, and RImean1) and after NAC (SUV2, RImax2, and RImean2).Results A total of 12 patients (39%) exhibited a good histologic response after NAC. SUVmax, RImax, and RImean significantly decreased after NAC. Before NAC, only RImean1 predicted the good histologic responders. The cut-off value, sensitivity, specificity, and accuracy of RImean1 for predicting good histologic response was < 10%, 92%, 58%, and 71%, respectively. After NAC, only SUV2 and RImax2 predicted good histologic responders. By using combined criterion of SUV2 and RImean1 or SUV2 and RImax2, accuracies were 77% respectively.Conclusions The histologic response after NAC could be predicted by using RImean1 before the initiation of NAC in osteosarcoma. The combined use of SUV2 and RI values may provide a better prediction of histologic response to NAC.Research Support This work was supported by Establishment of Center for PET Application Technology Development, Korea Institute of Radiological and Medical Sciences (KIRAMS), and by grants from the Ministry of Education, Science and Technology (50441-2015).