Iodine-124 PET(/CT) in differentiated thyroid cancer

124I-PET(/CT) has a high clinical potential in patients with differentiated thyroid cancer (DTC). Two aspects deserve special interest: Pre-therapeutic dosimetry and imaging. In the clinical application the pre-therapeutic 124I-PET dosimetry can lead to a significant alteration of the therapeutic procedure compared to standard therapy. 124I-PET dosimetry is a useful procedure in advanced DTC and may allow the application of safer or more effective radioiodine activities and earlier multimodal interventions than do standard empirical protocols. Used together, 124I-PET and CT allow localization of foci of highly specific 124I uptake as well as noniodine-avid lesions. The combination of whole-body 124I-PET/CT and FDG-PET improves restaging in recurrent DTC by enabling detection of local recurrence or metastases that are often not found if only one of the methods or other imaging modalities are applied. (orig.)