Modeling the absorbed dose to the common carotid arteries following radioiodine treatment of benign thyroid disease.

Introduction External fractionated radiotherapy of cancer increases the risk of cardio- and cerebrovascular events, but less attention has been paid to the potential side effects on the arteries following internal radiotherapy with radioactive iodine (RAI), i.e. 131-iodine. About 279 per million citizens in the western countries are treated each year with RAI for benign thyroid disorders (about 140,000 a year in the EU), stressing that it is of clinical importance to be aware of even rare radiation-induced side effects. In order to induce or accelerate atherosclerosis, the dose to the carotid arteries has to exceed 2 Gy which is the known lower limit of ionizing radiation to affect the endothelial cells and thereby to induce atherosclerosis.