Short Title:
Dose Rate Effects and GCR Simulation
Responsible HRP Element:
Space Radiation
Funding Status:
Planned-Funded - Task expected to be within budget
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Procurement Mechanism(s):
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Aims:
- Test the hypothesis that the time between doses and the dose-rate are critical modulators of mutant frequency in human cells following exposure to a mixed GCR field. Cultured human TK6 lymphoblasts will be used and the results compared with data obtained previously with these cells using acute exposures to single ions or rapidly delivered sequential beams.
- Test the hypothesis that the time between doses and dose-rate are critical modulators of mutational spectra following exposure to a mixed GCR field. We hypothesize that the types of TK1 mutations will be distinct from spontaneous events and that dose-rate and the time between exposures will alter the signature of radiogenic mutations.
Category:
Risk Characterization, Quantification
Subcategory:
Evidence or Risk Characterization
Description:
This project is designed to provide a comprehensive view of the impact of dose-rate on
an essential element of human carcinogenesis: autosomal mutation. The GCR component of the
radiation environment in deep space is largely one of low dose-rate exposures to low LET
radiations, punctuated with the occasional heavy ion, and can be considered a “mixed field”.
Here, mixed field studies are proposed that will deliver data on both mutant frequency and
mutational spectra as a function of dose and dose-rate, making use of different fractionation
schemes. These studies make use of extensive 1-ion acute data sets for a very sensitive indicator
of mutagenesis as well as state of the art genomics techniques. The combination of mutant
frequency data with mutational spectra will provide direct input to NASA’s risk model for
carcinogenesis and reduce uncertainties regarding dose-rate, thereby enabling a more reliable
estimate of safe days in space for exploration class missions.
Internal Customers:
None
External Customers:
None