Background & Aim: 5-iodo-2-deoxyuridine(Iudr) is a thymidine analog that is known as a radiosensitizer for human cancer cells in in vitro and in vivo studies. The investigations on the spheroid have shown that Iudr uptake of cells increases with the increasing Iudr incubation time. The aim of this study was to evaluate the extent of cytogenetic damage induced by ionizing radiation at differ...