Long term follow up of patients treated for hyperthyroidism with low dose radioactive iodine.

RADIOACTIVE iodine (iodine-131) has been used extensively during the past 30 years for the treatment of hyperthyroidism and has been shown to control this disorder in the majority of cases in which it has been used. There have been varying reports of the incidence of post-radiation hypothyroidism which has been reported to be as high as 70 per cent in patients followed up for 10 years (Beling and Einhorn, 1961; Dunn and Chapman, 1964; Nofal, Beierwaltes and Patno, 1966; Green and Wilson, 1969). In recent years smaller doses of iodine-131 have been used to try to minimise this complication (Smith and Wilson, 1967; Hagen, Ouellette and Chapman, 1967; Hagen, 1968; Smith, Munro and Wilson, 1970, Blahd and Hays, 1972; Rapoport, Caplan and De Groot, 1975).