Authors: Sergios Gatidis Holger Schmidt Christian la Fougère Konstantin Nikolaou Nina F Schwenzer Jürgen F Schäfer
Publish Date: 2016/08/26
Volume: 43, Issue: 13, Pages: 2283-2289
Abstract
30 18FFDGPET/MRI examinations were performed on 24 patients with known or suspected solid tumors 10 girls 14 boys age 12 ± 56 1–18 years PET scan duration 4 min per bed position Lowactivity PET images were retrospectively simulated from the originally acquired data sets using randomized undersampling of list mode data PET data of different simulated administered activities 025–25 MBq/kg body weight were reconstructed with or without point spread function PSF modeling Mean and maximum standardized uptake values SUVmean and SUVmax as well as SUV variation SUVvar were measured in physiologic organs and focal FDGavid lesions Detectability of organ structures and of focal 18FFDGavid lesions as well as the occurrence of falsepositive PET lesions were assessed at different simulated tracer activitiesSubjective image quality steadily declined with decreasing tracer activities Compared to the originally acquired data sets mean relative deviations of SUVmean and SUVmax were below 5 at 18FFDG activities of 15 MBq/kg or higher Over 95 of anatomic structures and all pathologic focal lesions were detectable at 15 MBq/kg 18FFDG Detectability of anatomic structures and focal lesions was significantly improved using PSF No falsepositive focal lesions were observed at tracer activities of 1 MBq/kg 18FFDG or higher Administration of 18FFDG activities of 15 MBq/kg is thus feasible without obvious diagnostic shortcomings which is equivalent to a dose reduction of more than 50 compared to current recommendationsSignificant reduction in administered 18FFDG tracer activities is feasible in pediatric oncologic PET/MRI Appropriate activities of 18FFDG or other tracers for specific clinical questions have to be further established in selected patient populationsAll procedures performed in studies involving human participants were in accordance with the ethical standards of the 1964 Helsinki Declaration and its later amendments or comparable ethical standards This study was performed retrospectively on existing clinical imaging data All legal guardians had given their written informed consent for the scientific analysis of acquired imaging data Due to the retrospective nature of this study formal approval was waived by the local ethics committee
Keywords: