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Induction of micronuclei in human fibroblasts across the Bragg curve of energetic heavy ionsThe space environment consists of a varying field of radiation particles including high energy ions, with spacecraft shielding material providing the major protection to astronauts from harmful exposure. Unlike low-L or X-rays, the presence of shielding does not always reduce the radiation risks for energetic charged particle exposure. Although the dose delivered by the charged particle increases sharply as the particle approaches the Bragg peak, the Bragg curve does not necessarily represent the biological damage along the particle traversal. The "biological Bragg curve" is dependent on the energy and the type of the primary particle, and may vary for different biological endpoints. To investigate "biological Bragg curves", we analyzed micronuclei (MN) induction along the particle traversal of Si and Fe ions at incident energies of 300 MeV/nucleon and 1 GeV/nucleon. A quantitative biological response curve did not reveal an increased yield of MN at the location of the Bragg peak. However, the ratio of mono-to bi-nucleated cells, which indicates inhibition in cell progression, increased at the Bragg peak location. These results confirm the hypothesis that "over kill" at the Bragg peak will affect the outcome of other biological endpoints.
Document ID
20060020700
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Hada, Megumi
(NASA Johnson Space Center Houston, TX, United States)
Rusek, Adam
(Brookhaven National Lab. Upton, NY, United States)
Cucinotta, Francis A.
(NASA Johnson Space Center Houston, TX, United States)
Wu, Honglu
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2006
Subject Category
Space Radiation
Meeting Information
Meeting: 53rd Annual Meeting Radiation Research Society
Location: Philadelphia, PA
Country: United States
Start Date: November 5, 2006
End Date: November 8, 2006
Distribution Limits
Public
Copyright
Other

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