title: DNA DSB induced by iron ions in human fibroblasts: LET dependence and shielding efficiency.
abstract: This paper reports on DNA DSB induction in human fibroblasts by iron ions of different energies, namely 5, 1 GeV/u, 414 and 115 MeV/u, in absence or presence of different shields (PMMA, Al and Pb). Measure of DNA DSB was performed by calibrated Pulsed Field Gel Electrophoresis using the fragment counting method. The RBE-LET relationships for unshielded and shielded beams were obtained both in terms of dose average LET and of track average LET. Weak dependence on these parameters was observed for DSB induction. The shielding efficiency, evaluated by the ratio between the cross sections for unshielded and shielded beams, depends not only on the shield type and thickness, but also on the beam energy. Protection is only observed at high iron ions energy, especially at 5 GeV/u, where PMMA shield gives higher protection compared to Al or Pb shields of the same thickness expressed in g/cm2.
authors.affiliation: Laboratorio di Fisica, Technology and Health Department, Istituto Superiore di Sanita, Rome, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Esposito
authors.forename: F
authors.initials: F
authors.lastname: Antonelli
authors.forename: M
authors.initials: M
authors.lastname: Belli
authors.forename: A
authors.initials: A
authors.lastname: Campa
authors.forename: V
authors.initials: V
authors.lastname: Dini
authors.forename: Y
authors.initials: Y
authors.lastname: Furusawa
authors.forename: G
authors.initials: G
authors.lastname: Simone
authors.forename: E
authors.initials: E
authors.lastname: Sorrentino
authors.forename: M A
authors.initials: MA
authors.lastname: Tabocchini
mesh_terms: D000535:Aluminum; D002460:Cell Line; D003359:Cosmic Radiation; D004249:DNA Damage; D005347:Fibroblasts / Q000528:radiation effects*; D020450:Heavy Ions; D006801:Humans; D007501:Iron; D007854:Lead; D018499:Linear Energy Transfer; D019904:Polymethyl Methacrylate; D011829:Radiation Dosage; D011835:Radiation Protection; D012062:Relative Biological Effectiveness; D017356:Synchrotrons
chemical_list: D007854:Lead; D019904:Polymethyl Methacrylate; D000535:Aluminum; D007501:Iron