Dose Rate Effects on Hydrated Electrons, Hydrogen Peroxide, and a OH Radical Molecular Probe Under Clinical Energy Protons.

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  • Additional Information
    • Source:
      Publisher: Radiation Research Society Country of Publication: United States NLM ID: 0401245 Publication Model: Print Cited Medium: Internet ISSN: 1938-5404 (Electronic) Linking ISSN: 00337587 NLM ISO Abbreviation: Radiat Res Subsets: MEDLINE
    • Publication Information:
      Publication: Bozeman, MT : Radiation Research Society
      Original Publication: Charlottesville, VA : Kluge Carden Jennnings Pub. Co.
    • Subject Terms:
      Protons* ; Hydrogen Peroxide*; Electrons ; Water/chemistry
    • Abstract:
      We report the dose rate dependence of radiation chemical yields (G value) of water radiolysis products under clinical energy protons (230 MeV) to understand mechanisms of the FLASH radiotherapy performed at ultra-high dose rate (>40 Gy/s). The G value of 7-hydoroxy-coumarin-3-carboxylic acid (7OH-C3CA) produced by reactions of coumarin-3-carboxylic acid (C3CA) with OH radicals and oxygen is evaluated by fluorescence method. Also, those of hydrated electrons and hydrogen peroxide are derived by absorption method using Saltzman and Ghomley techniques, respectively. Both G values of 7OH-C3CA and hydrated electrons decrease with increasing dose rate. The relative evolution of 7OH-C3CA is -39 ± 2% between 0.1 and 50 Gy/s. This value is higher than that of hydrated electrons, measured at -21 ± 4%. The G value of hydrogen peroxide in ultra-pure water also decreases with increasing dose rate. In comparison to these findings, we represent the increase of the G value of hydrogen peroxide with increasing dose rate in the mixture solution of MeOH and NaNO3, which act as scavengers of OH radicals and hydrated electrons, respectively, that decompose hydrogen peroxide. This finding indicates that a complex track structure can be expected with increasing dose rate and the reduction of OH radicals by forming hydrogen peroxide would be related to the sparing effect of healthy tissues.
      (©2024 by Radiation Research Society. All rights of reproduction in any form reserved.)
    • Accession Number:
      0 (Protons)
      BBX060AN9V (Hydrogen Peroxide)
      059QF0KO0R (Water)
    • Publication Date:
      Date Created: 20240226 Date Completed: 20240410 Latest Revision: 20240819
    • Publication Date:
      20240819
    • Accession Number:
      10.1667/RADE-23-00244.1
    • Accession Number:
      38407439