Comment on 'Monte Carlo calculated microdosimetric spread for cell nucleus-sized targets exposed to brachytherapy (125)I and (192)Ir sources and (60)Co cell irradiation'.
The relative standard deviation, σr,D, of calculated multi-event distributions of specific energy for (60)Co ϒ rays was reported by the authors F Villegas, N Tilly and A Ahnesjö (Phys. Med. Biol. 58 6149-62). The calculations were made with an upgraded version of the Monte Carlo code PENELOPE. When the results were compared to results derived from experiments with the variance method and simulated tissue equivalent volumes in the micrometre range a difference of about 50% was found. Villegas et al suggest wall-effects as the likely explanation for the difference. In this comment we review some publications on wall-effects and conclude that wall-effects are not a likely explanation.
Tellusborgsvägen 108, SE 126 28 Hägersten, Sweden.
Lennart
L
Lindborg
Jan
J
Lillhök
Jan-Erik
JE
Grindborg
D001918:Brachytherapy / Q000379:methods*; D002467:Cell Nucleus / Q000528:radiation effects*; D004781:Environmental Exposure / Q000032:analysis*; D007496:Iridium Radioisotopes / Q000627:therapeutic use*; D009010:Monte Carlo Method
D007496:Iridium Radioisotopes