physieal and mental can distort thyroid func­ Thyroid diseases are common. They indude hyper- and hypothyroidism, enlargement of tion tests so that thyroid dysfunction is dia­ the gland both diffuse and nodular, solitary gnosed inappropriately. This is addressed in nodules both benign and malignant, in­ Chapter 12 with adviee that should de­ crease this occurrence. Because radiation flammatory diseases, rare congenital defects to the thyroid can cause dinieally relevant in structure and inborn errors in function. thyroid disease and because some of the Many are simple to diagnose and treat, others are not. The literature often com­ diagnostic tests and treatments involve plicates rather than simplifies issues. My in­ administration of radioactive iodine to the tention is to use personal experience, the patient, Chapter 13 brings together some teaching of others and distillation of the aspects of radiation biology in relation the literature as the basis for a text which will the thyroid.