Space radiation exposures differ from exposures on earth. On Earth humans are subject to background radiation from the environment including our foods taking up radionuclides in the soils grown from cosmic radiation, which can vary by altitude, and more and more through diagnostic or therapeutic medical exposures. The radiations a human would see on a deep space mission—that is, one outside of the protective magnetosphere of the earth—are unique in that they represent the remnants of the Big Bang and include charged particles of every element of the periodic chart. These highly energetic charged particles present challenges in determining the risk for radiation-induced carcinogenesis as these particles in studies on Earth have been shown to have the potential to be highly carcinogenic. The estimations for radiation-induced carcinogenesis for an interplanetary mission to Mars exceeds the permissible exposure limits for estimated risk of (radiation) exposure-induced death.
Two tissues for which the risk for carcinogenesis and, ultimately death, include the liver and the lung. These two research projects address our attempts to understand the carcinogenic process in these tissues, determine whether tumors in these tissues are more aggressive, determine if there are sex differences in the risk for carcinogenesis (lung), and attempt to develop biomarkers of the early onset of disease.