We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Biological effectiveness of accelerated protons for chromosome exchanges.
- Authors
George, Kerry A.; Hada, Megumi; Cucinotta, Francis A.
- Abstract
We have investigated chromosome exchanges induced in human cells by seven different energies of protons (5-2500 MeV) with LET values ranging from 0.2 to 8 keV/μm. Human lymphocytes were irradiated in vitro and chromosome damage was assessed using three-color fluorescence in situ hybridization chromosome painting in chemically condensed chromosomes collected during the first cell division post irradiation. The relative biological effectiveness (RBE) was calculated from the initial slope of the dose-- response curve for chromosome exchanges with respect to low dose and low dose-rate γ-rays (denoted as RBEmax), and relative to acute doses of γ-rays (denoted as RBEγAcute). The linear dose--response term was similar for all energies of protons, suggesting that the decrease in LET with increasing proton energy was balanced by the increase in dose from the production of nuclear secondaries. Secondary particles increase slowly above energies of a few hundred megaelectronvolts. Additional studies of 50 g/cm² aluminum shielded high-energy proton beams showed minor differences compared to the unshielded protons and lower RBE values found for shielded in comparison to unshielded beams of 2 or 2.5 GeV. All energies of protons produced a much higher percentage of complex-type chromosome exchanges when compared to acute doses of γ-rays. The implications of these results for space radiation protection and proton therapy are discussed.
- Subjects
SISTER chromatid exchange; CHROMOSOME abnormalities; RELATIVE biological effectiveness (Radiobiology)
- Publication
Frontiers in Oncology, 2015, p1
- ISSN
2234-943X
- Publication type
Article
- DOI
10.3389/fonc.2015.00226