Abstract

Radioactive iodine (I-131) has been used for more than six decades for the treatment of thyrotoxicosis. Radiation safety is of paramount importance in I-131 based treatment of thyroid diseases, as treated patients become a potential radiation hazard for other individuals. The purpose of this article is estimation of the time period for radiation safety restrictions through assessments of total effective dose equivalent (TEDE) in individuals exposed to I-131 for thyrotoxicosis therapy, by incorporating into the calculations, various factors such as relevant socioeconomic conditions. For performing patient-specific dose calculations, we have used published data of uptake fractions & effective half-lives and triexponential model for total body clearance of iodine-131. Results obtained showed that the TEDE to other individuals (especially the family members, particularly children) and general public may be much higher than the annual dose limits recommended by the International Atomic Energy Agency (IAEA) and International Commission for Radiation Protection (ICRP) in some situation especially when the administered activity is greater than 15 mCi and occupancy factor greater than 0.125 and proper precautionary measures are not taken after the release from hospital. It is therefore suggested that a fixed dose limit of 15 mCi (550 MBq) instead of 30 mCi (1100 MBq) be recommended for release of I-131 thyrotoxicosis therapy patients in order to reduce undesired exposure to caregivers and general public in countries like Pakistan because of factors such as poor socioeconomic conditions and low literacy rates, etc.