title: New shielding materials for clinical electron beams.
abstract: Since lead has recently been recognized as a source of environmental pollution, we have investigated new electron shielding materials that do not contain lead. We compared the shielding thicknesses of a hard plate and a sheet composed of the new materials with that of lead for electron beams. The shielding thickness was evaluated as the thickness required for shielding primary electrons. The comparison revealed the shielding ability of the hard plate and sheet is approximately equivalent to 1.0 and 0.9 times that of lead, respectively. The thickness (in millimeters) required for shielding by the hard-plate, as well as the thickness of lead, is related to approximately half of the electron-beam energy (in MeV). The shielding ability of the sheet is also equivalent to that of Lipowitz alloy. Moreover these materials are environmentally friendly, and can be easily customized into arbitrary shapes. Therefore they can be used as lead substitutes for shielding against electron beams.
authors.affiliation: Research Center Hospital for Charged Particle Therapy, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan. m_taiiri@nirs.go.jp
authors.forename: Minoru
authors.initials: M
authors.lastname: Tajiri
authors.forename: Yuji
authors.initials: Y
authors.lastname: Tokiya
authors.forename: Jun
authors.initials: J
authors.lastname: Uenishi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Sunaoka
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Watanabe
mesh_terms: D000465:Algorithms; D004583:Electrons; D006801:Humans; D007854:Lead; D008422:Materials Testing; D017785:Photons; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D011874:Radiometry; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D020266:Radiotherapy, Conformal
chemical_list: D007854:Lead