WHOLE-BODY SCAN WITH I-131 ADVANTAGE OF DELAYED IMAGES FOR THE DETECTION OF THYROID-CANCER METASTASES

In the follow-up of thyroid cancer patients we sometimes observed discrepancies between elevated thyroglobulin levels and negative results of posttherapeutic or diagnostic scans 48 h and 72 h after oral application of I-131 routinely. Consequently, delayed I-131 scans (96 h and later) were performed in addition. In all cases, delayed I-131 scans either showed a higher imaging quality or additional metastatic lesions. Thus, posttherapeutic (and diagnostic) scans should include late images (4 d and later).