Chromosome aberrations after high-dose 131I and 99mTc-MIBI administration using a micronucleus assay

Objective: We evaluated the potential detrimental cytogenetic effects of 99mTc-methoxyisobutyl isonitrile (MIBI) and 131I on patients who were exposed to the radiopharmaceutics for cardiac imaging or thyroid cancer therapy, respectively. Methods: Mononuclear leukocytes were isolated both before and after radiopharmaceutical administration and subsequently cultured. Micronuclei frequency was then assessed and microscopic evaluation of apoptosis was conducted. Results: Small statistically insignificant augmentation in the percentage of micronuclei from 10.9 ± 3.8 to 11.3±2.4 was observed in the 99mTc-MIBI group. In contrast, 131I elicited a notable augmentation of micronuclei from 6.3± 2.2 to 9.6± 3.1 at 3.7GBq, and 6 ±1.5 to 9.2±2.7 at 5.55GBq (P <0.05). Conclusion: Our results showed that there were no remarkable alterations either in the micronuclei incidence or in the percentage of apoptotic lymphocytes after in-vivo exposure to radiopharmaceutical imaging, which provides evidence to reduce the growing concern about the safety issue of cardiac imaging with 99mTc-MIBI, whereas the deleterious effects of 131I must be considered when it is applied to thyroid cancer treatment. © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins