Gap Cancer-102: Determine the role of radiation quality on carcinogenesis and shared biology with other degenerative diseases.
Last Published:  03/26/21 03:33:57 PM (Central)
Responsible Element: Space Radiation (SR)
Status: Open
The predominant factor contributing the most uncertainty to risk of exposure-induced death (REID) estimates is radiation quality. Space radiation exposure differs from that experienced by humans in the terrestrial environment, specifically in the type of radiation. Whereas terrestrial exposures are comprised predominately of photons and radioactive decay emission (X- or γ-rays, alpha particles, beta particles), space radiation exposure encompasses a mixture of different ion species ranging from hydrogen to gold and larger. The impact of these mixed fields on carcinogenesis and related outcomes are not well characterized. Evidence from animal models indicates that high-energy and charge particle (HZE) irradiation increases tumor incidence in a dose- and species-dependent manner when compared to photon irradiation with relative biological effectiveness (RBE) values ranging from 1 to over 50 in some solid tumor types. Additional evidence suggests that HZE irradiation may shorten the time to tumor malignancy and produce tumors that are more aggressive. Furthermore, it is not known whether interactions between different ion species in a mixed field further contributes to carcinogenic risk. Therefore, research characterizing the effect of radiation quality on radiation carcinogenesis is critical for appropriate extrapolation of excess risk from available human epidemiological data. Furthermore, the underlying biological mechanisms implicated in radiation-associated carcinogenesis may also affect development of other degenerative diseases providing opportunities to identify shared pathways for cross-functional outcome monitoring and mitigation. Characterization of the role radiation quality plays in space radiation associated carcinogenesis will also provide potential targets for countermeasures and mitigation strategies. 

Ground-based research using appropriate in vitro and in vivo models to acquire the necessary data sets for accurate estimation of radiation quality effects for protons, heavy ions, and secondary neutrons. NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) supports multiple ion and mixed field studies with fast ion switching for more complex mixed-field GCR simulations. Additional approaches also include advanced biostatistical methods to combine past, current, and future research results into data-driven model.

Target for Closure

·        Characterization of the contribution of and type of interaction (additive, synergistic, etc) between individual species of the space radiation environment on radiation-associated cancer risk

·        Data-driven models of radiation quality effects that can be implemented to scale epidemiological excess cancer risk estimates to the space radiation environment

Risk Risk of Radiation Carcinogenesis
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