Scintigraphy of the functioning thyroid nodule

The evaluation of functioning thyroid nodules is achieved by use of several Iodine isotopes, while in clinical routine 99mTc-Pertechnetate is dominating. For classification the terms hyperfunctional, isofunctional (normal) and hypofunctional are useful in comparison to the surrounding normally functioning thyroid tissue, which can be stimulated or suppressed. Therefore, autonomous functioning thyroid nodules can vary the scintigraphic appearance. For precise description the terms 'compensation' and 'decompensation' have to be used in relation to scintigraphy or thyroidal metabolism (regulation). (orig.)