Measurements of G values for DNA damage induced by low-energy electrons.
We address the problem of measuring G values (damage per unit of deposited energy) for low-energy electrons (LEEs) below 30 eV. Such values (G(LEE)) usually have to be derived from damage yields in nanometer- (~10-nm-) thick films, which are too thin to allow complete absorption of the energy of LEEs. In this work, we determine optimum corrections to obtain reliable G(LEE) values in 2-80-nm-thick films of plasmid DNA that are not uniform. G(LEE) was found to increase with average film thickness and reach a plateau at 260 ± 50 nmol/J around 20 nm, which corresponds to the most reliable value. The previously measured G(LEE) values for films thinner than 20 nm that were underestimated can be corrected using a factor derived from the present results. This method could be used to obtain reliable G(LEE) values for other biomolecules so as to enable the comparison of LEE-induced damage to that produced by other types of radiation under various experimental conditions.
Département de médecine nucléaire et radiobiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada. Elahe.Alizadeh@USherbrooke.ca
Elahe
E
Alizadeh
Léon
L
Sanche
D000042:Absorption; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D004583:Electrons; D014965:X-Rays
D004247:DNA