title: [DEMONSTRATION OF LIKELIHOOD OF THE NEGATIVE EFFECT OF PHYSICAL PROTECTION DURING TOTAL PROTON IRRADIATION OF MICE].
abstract: The experiments were performed with outbred CD-1 male mice (SPF category). Total irradiation at 1.0; 2.5 and 5.0 Gy by protons with the average energy of 170 MeV was conducted in a level medical beam of the phasotron at the Joint Institute of Nuclear Investigations. Targets were 2 points of in-depth dose distribution, i.e. beam entrance of the object, and modified Bragg peak. As a physical protector, the comb filter increases linear energy transfer (LET) of 170 MeV entrance protons from 0.49 keV/μm to 1.6 keV/μm and, according to the bone marrow test, doubles the biological effectiveness of protons when comparing radiation doses that cause 37% inhibition of blood cell formation in the bone marrow. Physical protection increases dose rate from 0.37 Gy/min for entrance protons to 0.8 Gy/min for moderated protons which more than in thrice reduces time of irradiation needed to reach an equal radiobiological effect.
authors.forename: A A
authors.initials: AA
authors.lastname: Ivanov
authors.forename: T M
authors.initials: TM
authors.lastname: Bulynina
authors.forename: A G
authors.initials: AG
authors.lastname: Molokanov
authors.forename: S V
authors.initials: SV
authors.lastname: Vorozhtsova
authors.forename: D M
authors.initials: DM
authors.lastname: Utina
authors.forename: Yu S
authors.initials: YS
authors.lastname: Severyukhin
authors.forename: I B
authors.initials: IB
authors.lastname: Ushakov
mesh_terms: D000818:Animals; D021461:Animals, Outbred Strains; D001853:Bone Marrow / Q000473:pathology / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D004920:Erythropoiesis / Q000528:radiation effects*; D005260:Female; D051379:Mice; D009929:Organ Size; D011522:Protons / Q000009:adverse effects*; D011835:Radiation Protection; D011874:Radiometry; D013154:Spleen / Q000473:pathology / Q000528:radiation effects*; D017356:Synchrotrons; D014916:Whole-Body Irradiation
chemical_list: D011522:Protons