title: Experimental simulation of proton space radiation environments:  a dosimetric perspective.
abstract: Three-dimensional dose calculation techniques developed for radiotherapy treatment planning were used to calculate dose distributions from unidirectional, planar rotational and omnidirectional incident radiation (experimental proton beams and  solar flares).  The calculations predicted regions of high dose within primate heads exposed to 55-MeV protons, supporting the postulate of radiation-induced brain tumors within this population.  Comparisons among predicted doses to the human head  from solar flares of three different energies demonstrated differences between unidirectional and omnidirectional irradiation in the space environment.  The results can be used to estimate dose distributions based on a) limited phantom measurements, or b) nonuniformly incident radiation in orbit; both situations are difficult to replicate under laboratory exposure conditions.
authors.affiliation: AL/OEBSD, USAF Armstrong Laboratory, Brooks AFB, TX 78235-5000, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Hardy
authors.forename: D D
authors.initials: DD
authors.lastname: Leavitt
mesh_terms: D000818:Animals; D001921:Brain / Q000528:radiation effects; D003198:Computer Simulation; D005123:Eye / Q000528:radiation effects; D006801:Humans; D008954:Models, Biological; D009381:Neoplasms, Radiation-Induced; D019047:Phantoms, Imaging; D011522:Protons; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation; D011878:Radiotherapy; D019445:Solar Activity; D014057:Tomography, X-Ray Computed
chemical_list: D011522:Protons