Is the increased relative biological effectiveness of high LET particles due to spatial or temporal effects? Characterization and OER in V79-4 cells.

摘要: The efficiency of producing biological damage varies with radiation quality. Conventional explanations rely on spatial differences in the track structure; generally however there are also very large temporal delivery at cellular level. High-LET normally deposits substantial amounts energy by individual heavily ionizing tracks a timescale order picoseconds. By contrast each low-LET small amount energy. Many these tracks, distributed over whole cell, required to deliver an equivalent dose high-LET and they usually delivered much longer timescales (typically seconds) during which chemical, biochemical processes occurring. In this paper design, characterization initial application high-brightness, laser-plasma ultrasoft x-ray source is described. This has been used investigate importance irradiating mammalian cells deposition properties similar radiation. present system delivers typical dose, incident surface cells, 0.12 Gy per pulse <10 ps. capabilities were tested determining survival V79-4 hamster irradiated picosecond pulses x-rays under aerobic anaerobic conditions, found be consistent previously published non pulsed data These results support expectation that disappearance oxygen effect for particles due their rather than short particle traversal. For other effects, particularly non-targeted phenomena such as induced genomic instability, expectations may less clear cut.