Incremental value of 131I-SPECT/CT study in evaluation of patients with differentiated thyroid cancers

Full text: 131I planar scintigraphy has been the conventional modality for identifying residual and metastatic disease in patients with differentiated thyroid cancers. With the availability of SPECT/CT it would be imperative to evaluate if 131I-SPECT/CT may have an additional value over planar imaging. The aim of the present study was to investigate whether 131I-SPECT/CT has any incremental value over planar scan in identifying remnant disease, local and distant metastases and its impact on therapeutic management. Planar and SPECT/CT imaging of 48 post thyroidectomy patients were retrospectively analyzed. The planar and SPECT/CT imaging included diagnostic and post therapeutic scans. Whenever SPECT/CT identified iodine uptake foci to a more correct anatomic localization and/or precisely demarcated the tumor from physiological areas of radiotracer uptake, an incremental value was assigned. Overall, SPECT/CT detected more definitive foci than planar in 13% of patients. SPECT/CT had an incremental value in 38% of patients. SPECT/CT modified therapeutic management in 23% of positive cases which included adjustment of 131I therapeutic dose, need for repeat surgery and avoidance of unnecessary radio-iodine treatment