"When CT is employed in follow-up, this is often performed without contrast in the early post-operative period if radioiodine ablation has not been performed, since iodinated contrast can compete with radioiodine treatment for uptake. If a study with IV contrast is necessary, radioiodine can be administered 4–8 weeks following the injection of contrast medium 5."
"when neck ultrasound is felt to be inadequately visualising possible neck nodal disease (e.g. high thyroglobulin, negative neck US)"
"when neck ultrasound is felt to be inadequately visualising possible neck nodal disease (e.g. high thyroglobulin, negative neck US)"