title: Probability of hippocampus cell hits by high-LET space radiation in a low-Earth-orbit mission (STS-91).
abstract: High-LET particles (HLP) of space radiation in the brain were measured with plastic nuclear track detectors (PNTD) using a life-size human phantom in the 9th Shuttle-Mir Mission (STS-91). Relationship between PNTD track-formation sensitivity (S) and LET infinity H2O was examined using heavy-ion beams at NIRS-HIMAC. Average fluence of the HLP (HLP10) with LET infinity H2O greater than 10 keV micrometers-1 was evaluated as 1.3 x 10(4) n cm-2 for the 9.8-day low-Earth-orbit mission (400 km x 51.65 degrees). Based on a simple extrapolation of these data, probability of HLP10 hits to hippocampus cells and cell-nuclei were estimated to be 45% and 7.0%, respectively, in a 90-day ISS mission. For 1 year, 91% of cells and 25% of cell-nuclei will be hit by HLP10.
authors.affiliation: National Institute of Radiological Sciences 4-9-1 Anagawa, Inage-ku, Chiba, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yasuda
authors.forename: T
authors.initials: T
authors.lastname: Komiyama
authors.forename: K
authors.initials: K
authors.lastname: Fujitaka
mesh_terms: D002467:Cell Nucleus / Q000528:radiation effects*; D005118:Extraterrestrial Environment; D020450:Heavy Ions; D006624:Hippocampus / Q000166:cytology / Q000528:radiation effects*; D006801:Humans; D018499:Linear Energy Transfer; D009474:Neurons / Q000528:radiation effects*; D019047:Phantoms, Imaging; D010969:Plastics; D011092:Polyethylene Glycols; D011336:Probability; D011829:Radiation Dosage; D011834:Radiation Monitoring / Q000295:instrumentation; D011874:Radiometry; D013026:Space Flight
chemical_list: D010969:Plastics; C028827:CR 39; D011092:Polyethylene Glycols