Article
Proton-HZE-Particle Sequential Dual-Beam Exposures Increase Anchorage-Independent Growth Frequencies in Primary Human Fibroblasts
Radiation Research
(2006)
Abstract
The radiation field in deep space contains high levels of high-energy protons and substantially lower levels of high-atomic-number, high-energy (HZE) particles. Calculations indicate that cellular nuclei of human space travelers will be hit during a 3-year Mars mission by ∼400 protons and ∼0.4 HZE particles. Thus most cells in astronauts will be hit by a proton(s) before being hit by an HZE particle. To investigate effects of dual ion irradiations on human cells, we irradiated primary human neonatal fibroblasts with protons (1 GeV/nucleon, 20 cGy) followed from 2.5 min to 48 h later by iron or titanium ions (1 GeV/nucleon, 20 cGy) and then measured clonogenic survival and frequency of anchorage-independent growth. This frequency depends on the interval between hydrogen- and iron-ion irradiation, with a critical window between 2.5 min and 1 h producing about three times more anchorage-independent colonies per survivor than expected from simple addition of the two ions separately. The hydrogen-titanium-ion dual-beam irradiation produced similar increases that persisted to ∼6 h. At longer intervals, anchorage-independent growth frequencies were similar to those expected for additivity. However, irradiation of cells with either an iron or a titanium particle first followed by protons produced only additive levels.
Disciplines
Publication Date
September, 2006
DOI
doi/abs/10.1667/RR0596.1
Citation Information
Noelle L Cutter. "Proton-HZE-Particle Sequential Dual-Beam Exposures Increase Anchorage-Independent Growth Frequencies in Primary Human Fibroblasts" Radiation Research Vol. 166 Iss. 3 (2006) p. 488 - 494 Available at: http://works.bepress.com/noelle-cutter/19/