title: A microdosimetric interpretation of the radiobiological effectiveness of 125I and the problem of quality factor.
abstract: When considering the microdosimetric energy deposition in small biological targets the Auger electron emitter 125I behaves like a high-LET radiation. For a specific incorporation in sensitive biological volumes of 20 nm in diameter a mean lineal energy of gamma F approximately equal to 270 keV micron-1 has been evaluated. Experimental data on transformation, mutation and chromosome aberration from DNA-bound 125I are interpreted to yield RBE-values, relative to 200 kV X rays, of 32 to 38 (transformations), 1 to 16 (mutations) and 6 to 77 (chromosome aberrations). Thus the RBE for transformation and chromosome aberration tends to be larger than the ICRP recommended high-LET quality factor (Q = 20). The implications of these results for the function Q(L) applied in radiation protection will be discussed.
authors: Institut für Medizin, Kernforschungsanlage Jülich, Federal Republic of Germany.
authors: E
authors: E
authors: Pomplun
authors: J
authors: J
authors: Booz
authors: A
authors: A
authors: Dydejczyk
authors: L E
authors: LE
authors: Feinendegen
mesh_terms: D000818:Animals; D002460:Cell Line; D002869:Chromosome Aberrations; D006224:Cricetinae; D004247:DNA / Q000528:radiation effects*; D004249:DNA Damage; D004735:Energy Transfer; D007457:Iodine Radioisotopes
chemical_list: D007457:Iodine Radioisotopes; D004247:DNA