Final answer:
Water-soluble iodine contrast media are crucial for visualizing the thyroid gland in medical diagnostics and treatment. Iodine is concentrated in the thyroid gland, and the most active cells, including cancerous ones, emit the most radiation when iodine is present.
Step-by-step explanation:
Water-soluble iodine contrast media are important for visualizing the thyroid gland in medical diagnostics. The thyroid gland absorbs most of the iodine, allowing it to be imaged for diagnostic purposes or preferentially targeted for treatment purposes. Iodine is concentrated in the thyroid gland and the most active thyroid cells, including cancerous cells, concentrate the most iodine and emit the most radiation.