Hemodialysis in patients requiring 131I treatment for thyroid carcinoma

Thyroid malignancies can be treated by surgery followed by ablation of the remnant tissue with 131I. As iodide removal from the body occurs by renal extraction, in patients suffering from end-stage renal disease it is necessary to properly evaluate both timing and method of the extracorporeal treatment. We present two patients on regular hemodialysis, admitted in isolation to the Nuclear Medicine Department and treated with 131I for thyroid carcinoma diagnosed during the check-up for transplantation. Both patients underwent two hemodialysis sessions with a portable machine for CRRT (continuous renal replacement therapy), 24 and 48 hours after the administration of 50 mCi of 131I. The nursing staff were monitored with a dosimeter. Radioactivity of the patients, dialysate and urines were measured during hemodialysis. The greater reduction was obtained with the first dialysis, but in both patients a further, though shorter, hemodialysis at 48 hours was necessary for reaching a patient's radioactivity compatible with discharge. Radioactivity measured in the dialysate demonstrated the almost total removal of radioiodine by dialysis alone. In both patients, follow-up exams revealed a complete ablation of thyroid tissue, without signs of local recurrence. The dose of radioactivity of the dialysis staff was below allowable limits. We conclude that a successful reduction of radioactivity, without dispersing its therapeutic efficacy, can be obtained with daily hemodialysis with a CRRT machine in patients in isolation treated with 131I. A therapeutic model is proposed.