Task The Contribution of Delta Rays to the Chromosome Aberration Dose Response in Human Cells Irradiated with HZE Particles of Different Energy but the Same LET (Completed)
Last Published:  03/26/21 03:34:00 PM (Central)
Short Title: HZE Chromosome Aberration
Responsible HRP Element: Space Radiation
Collaborating Org(s):
Funding Status: Completed - Task completed and produced a deliverable
Procurement Mechanism(s):
We plan to test the hypothesis that these exchange complexity increases will be related to the primary particle energy and resultant maximum delta ray range. We plan to irradiate human skin cells with low and high energy beams matching LET (linear energy transfer; energy deposited per unit track length) and fluences so that the only variable will be particle energy. A dose response curve for chromosome exchanges irradiated with low particle fluences will be constructed. At the same time will also look for breaks that fail to rejoin.

One experiment will be conducted at low dose rate which will prevent damage from delta rays from being added to chromosome exchanges forming along primary particle tracks by spreading damage formation out in time and allowing some breaks to be repaired or exchanges to be completely formed before other breaks occurring later can be added to them. We also plan to grow populations from single surviving cells allowing us to measure the transmissibility of chromosome exchanges a number of cell generations removed from the irradiation. We plan to determine the shape of the exchange dose response curve for these particles at low doses and at low dose rate, processes involving the misrepair of radiation induced damage that could lead to carcinogenesis. At the same time we will look at terminal deletions and incomplete exchanges resulting from the cell’s failure to repair damage. Finally, we will look for exchanges found only in a fraction of the cells making up a clonal population indicating genomic instability, the process which drives carcinogenesis.
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