The Attenuation and Scattering in a Phantom of Gamma Rays from some Radionuclides used in Mould and Interstitial Gamma-ray Therapy

Abstract

Ionization chamber measurements inair and in a phantom show that scatter does not quite compensate for attenuation, as assumed in the Paterson-Parker dosage system, for the [gamma] rays from Ra226 + daughters, Au198, Ir192, Ta182, Cs137 and Co60. Exposures within the patient are slightly, but no clinically significantly lower than predicted, while the increase of surface doses due tobackscatter is also very small. All these isotopes can be used equally well for moulds or implants.