Purpose: 2-[ 18 F] fluoro-2-deoxy-d-glucose is a positron emitting isotope, which emits 511 keV γ-rays through annihilation process. These γ-rays can induce a variety of DNA damages in animal tissues. It is known that during PET-CT procedure most tissues irradiated with 4-9 mGy absorbed dose and 6-10 mSv whole body effective dose. The biological effects including DNA damages with different dose of fluorine 18 ( 18 F) is still the part of observation and recent research. After knowing the 18 F mediated DNA damage and its repair using time dependent radiation dose study in in-vitro cellular model may clear the understanding of radiation absorbed dose and their side effects including genotoxic effects at specific point of time. Methods: to check the early and late apoptosis in irradiated peripheral blood mononuclear cells (PBMCs), annexin V FITC tagged microscopic imaging was examined. To detect DNA double-strand breaks (DSBs), apoptosis and DNA repair, comet assay and γ-H2AX assay was used. BrdU incorporation assay was also performed to label the fragmented DNA. Results: significant amount of apoptotic cells were observed in PBMC after being irradiated for 120 min with absorbed dose of 8.22 mGy. The appearance of comets and number of foci are increasing in the cells irradiated with 8.22 mGy for 120 min and the amount of FITC tagged BrdU stain percentage confirms the presence of DSBs and apoptosis for longer exposure time (120 min). In DNA repair study, 24 h is the necessary time to repair the damaged cells. Conclusions: our time-and dosedependent study shows that radiation induced DSBs generation and cell apoptosis at low dose radiation of 18 F. 18 F has the capacity to damage DNA and induce apoptosis only if the cells are exposed for the longer period of time. However, all the damages are repaired within 24 h.