Aetiological Factors in Thyroid Malignancy - Ionising Radiation
A major and definite aetiological factor that has been demonstrated is ionising radiation to the thyroid gland, given, in the past in some centres, in non- sterilising dosages to infants and children. Doses reported to have induced thyroid carcinoma vary from a few Gy (1Gy=100 rad) given to epilate the scalp in the treatment of ring- worm, to 15Gy (1,500 rad) for the treatment of tuberculous glands in the neck. Other conditions include prophylactic irradiation of the thymus in infants and also therapeutic irradiation of acne, enlarged tonsils, skin tumours of the head and neck, and Hodgkin's and non-Hodgkin's lymphomas of the cervical lymph nodes.
