Study of cytogenetic toxicity of low-dose radioiodine therapy in hyperthyroid patients using a micronuclei assay

ObjectiveRadioiodine, in low doses, has been used as a treatment modality for hyperthyroidism worldwide for a long time. However, there is little information available on the severity of cytotoxicity of radioiodine at these low doses. The present investigation aimed to study the cytogenetic toxicity of low-dose radioiodine in hyperthyroid patients using a cytokinesis-blocked micronuclei (MN) assay.Materials and methodologyAll of the patients received radioiodine in the form of sodium iodine (oral form). Blood samples of these patients were collected before therapy and 3 months after therapy, and lymphocytes were analysed for MN assay.ResultsPeripheral blood lymphocytes were analysed in 74 hyperthyroid patients (52 men, 22 women). The results indicated a positive relationship between age and the frequency of MN. However, there was no statistically significant difference in MN frequency at 3 months after therapy in comparison with that before therapy.ConclusionThis study showed that the cytogenetic damage produced by low-dose radioiodine was transient and reversible. Thus, patients can be motivated to undergo this safe and easy procedure as a modality of treatment for hyperthyroidism.