title: Direct radiation action of heavy ions on DNA as studied by ESR-spectroscopy.
abstract: The effects of heavy ions on the mechanisms of free radical formation in DNA-constituents as compared to low-LET irradiation are investigated by means of Electron Spin Resonance (ESR) spectroscopy.  Dose-yield curves were measured at low (T < 100 K) and ambient temperatures in order to obtain the G-value, that is number of radicals formed per 100 eV absorbed energy.  These G-values show a characteristic LET-dependence and are one to two orders of magnitude lower than for low-LET irradiation.  Measurements on 2'Deoxycytidine at 300 K using combined heavy ion and X-ray irradiation methods suggested that this effect can be partially explained by a destruction of radicals during the irradiation.
authors.affiliation: Fachrichtung Biophysik und Phys. Grundlagen der Medizin, Universität des Saarlandes, Homburg/Saar, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Schaefer
authors.forename: J
authors.initials: J
authors.lastname: Hüttermann
authors.forename: G
authors.initials: G
authors.lastname: Kraft
mesh_terms: D000241:Adenosine / Q000032:analysis / Q000528:radiation effects; D003596:Cytosine / Q000032:analysis / Q000528:radiation effects; D004247:DNA / Q000032:analysis / Q000528:radiation effects*; D003841:Deoxycytidine / Q000032:analysis / Q000528:radiation effects; D003857:Deoxyuridine / Q000032:analysis / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals; D018499:Linear Energy Transfer; D009356:Neon; D011839:Radiation, Ionizing; D011853:Radiobiology / Q000379:methods; D013696:Temperature; D013941:Thymine / Q000032:analysis / Q000528:radiation effects; D014501:Uranium; D014965:X-Rays
chemical_list: D005609:Free Radicals; D003841:Deoxycytidine; D014501:Uranium; D009356:Neon; D003596:Cytosine; D004247:DNA; D000241:Adenosine; D013941:Thymine; D003857:Deoxyuridine