Gamma camera imaging in differentiated thyroid cancer

Abstract

Differentiated thyroid cancer (DTC) has an overall good prognosis. Still, precise initial staging as well as lifelong follow-up is usually required. Radioiodine planar imaging with iodine-123 (I-123) or radioiodine-131 (I-131) still is the standard for staging and follow-up after initial surgery and ablative/adjuvant or metastases-directed radioiodine therapy. Imaging with radioactive iodine is also used for risk-stratification. The absence of anatomical details on planar gamma camera imaging as well as the superimposition of areas with increased radioiodine uptake often lead to challenges in the interpretation of planar images resulting in false positive or negative findings with impact on the patient management. Hybrid SPECT/CT enables a more precise anatomical localization and better characterization of foci with increased tracer uptake when compared to planar imaging. The differentiation of pathological and physiological uptake is more easily possible, increasing the accuracy of imaging and reducing the rate of indeterminate findings. Besides, imaging using isotopes of radioiodine, in the last years, also several new tracers for gamma camera imaging have been developed and used, especially in clinical settings with no or low uptake of radioiodine in DTC tumor lesions.