Studies with Radioiodine

This paper, following one on the Function and Rate of I131 Uptake of Thyroid3 deals with the treatment of hyperthyroidism by that isotope. Its purpose is to present the method employed and the results obtained at the University of California School of Medicine. Certain concepts with regard to the place of I131 in the treatment of hyperthyroidism are included. Interest in the therapeutic use of radioiodine in hyperthyroidism at the University of California began in 1938 with the studies of Dr. Joseph G. Hamilton and the late Dr. Mayo H. Soley. These studies were interrupted by the war and later resumed in the Radiology Division of the Medical School. In the early part of this work Dr. Soley and other members of the University of California Thyroid Clinic handled the clinical phases. Dr. Soley later left the University and Dr. Morris E. Dailey assumed the direction of the Thyroid Clinic. All the radiation aspects were handled in the Division of Radiology. In 1946 studies on animals were carried out with particular reference to the destructive effect of radioiodine on the thyroid, its surrounding structures, the liver, and the kidneys. These studies encouraged us to believe that we could use radioiodine with relative safety in the treatment of patients with thyrotoxicosis. Patients to whom I131 was given for hyperthyroidism This report presents data on the first 100 consecutive patients to whom I131 was given for the treatment of hyperthyroidism after resumption of the work in 1945. Most of the patients came initially from the Thyroid Committee of the University of California School of Medicine, San Francisco. Many of the rest were sent to the Committee for clinical study. In retrospect, it appears from a review of the records that all the patients had hyperthyroidism at the time they were treated. Patients with nodular goiters and those who were known to be pregnant were not accepted for treatment. The diagnosis of hyperthyroidism was made by evaluation of the clinical status and the laboratory findings. Hyperthyroidism can be diagnosed only on clinical grounds. Laboratory data are helpful, but in themselves never establish the diagnosis. In taking the history of the patient all points were considered, but particular attention was paid to those which could be quantitated, such as increase in food intake, loss of weight, increase in frequency of stools, decrease in length of menstrual periods, and decrease in number of blankets used at night. Less emphasis was placed on such subjective symptoms as palpitation, nervousness, and irritability. In the frequent and difficult problem of differentiation between mild hyperthyroidism and the anxiety state, considerable weight was given to the constancy or accentuation of the symptoms from the time of their onset. In the physical examination all findings were considered. A constant elevation of the truly basal pulse rate was a requisite to the diagnosis.