Introduction
	Scanning of the thyroid using iodine isotopes is one of the oldest investigations in Nuclear Medicine. Many other nuclear medicine imaging techniques that were developed after the description of a scanning device for visualizing the distribution of 131I in the thyroid gland by Cassen et al. in 19511, like liver and spleen and bone marrow scintigraphy, are nowadays obsolete, whereas thyroid scanning still constitutes an important part of the routine output of a standard nuclear medicine department. The most important reason for this is without doubt that diagnostic scanning of the thyroid with 123I or 131I has a sequel in therapy. For instance if therapy with 131I were non-existent, conventional radiological imaging techniques combined with serum hormone and tumour marker assays would long ago have reduced nuclear medicine’s role in thyroid imaging. Newer, promising imaging techniques that have emerged in recent years also combine functional diagnostic imaging with the potential of subsequent treatment with the same radiopharmaceuticals. It is in this field of research, specifically in that of radiolabelled peptides, that progress in the treatment of thyroid cancer is expected to be made within the next years.