Genotoxicity of Thallium-201 in Patients with Angina Pectoris Undergoing Myocardial Perfusion Study

Abstract

Thallium-201 (²⁰¹Tl) has been widely used as a nuclear reagent for myocardial blood flow imaging. The purpose of this study was to investigate genotoxic effects of ²⁰¹Tl in patients with angina pectoris (n = 21), who had undergone myocardial perfusion imaging. Lymphocytes were isolated from each patient before, and 3, 30 and 90 days after ²⁰¹Tl administration (111 MBq, 3 mCi) and were analyzed for chromosomal aberrations, sister chromatid exchanges, mitotic index and replicative index. There were significant increases in chromosomal aberrations and sister chromatid exchanges 3 days after ²⁰¹Tl administration (p < 0.001), although no difference was noted in these values after 30 and 90 days (p > 0.05). Moreover, decreased mitotic index and replicative index were noted after 3 days of ²⁰¹Tl administration (p < 0.001). These results suggest that the administration of ²⁰¹Tl for myocardial blood flow imaging may induce genetic damage.