Background: Ionizing radiation induces lipid peroxidation and forms reactive oxygen species (ROS) within the cell. Due to their highly reactive state, ROS have short diffusion distances and quickly transfer unbalanced electrons to neighboring molecules. This transfer cycle continues until it finally culminates in the generation of reactive alkenals such as 4- hydroxynonenal (4HNE). Under normal conditions, intracellular 4HNE levels are controlled by conjugation to glutathione and are actively transported from the cell; RLIP76 protein has been determined to be the major transport protein involved in the efflux of 4HNE-conjugates. Radiation induces significant oxidative stress, and the increased levels of 4HNE conjugates overwhelm transport capacity