Assessment of the action of mixed irradiation.

Problems associated with the environmental and health perspectives of mixed irradiation are identified and the application of theoretical models is discussed. Four definitions of synergism were examined with regard to the action of mixed irradiation, and it was determined that all these definitions are inappropriate. Thus, I concluded that the term synergism or its synonym should not be used for the action of mixed irradiation unless a reasonable definition and evidence of the mechanism are provided. The Zaider-Rossi model and the extended Zaider-Rossi model, which can be applied to any type of mixed irradiation with two types of radiation, are useful for assessing the effects of mixed irradiation using the parameters for two types of single irradiation. Furthermore, models were proposed for very short and very long simultaneous mixed irradiation with multiple types of radiation. These models also would be helpful to assess the environmental and health perspectives of mixed irradiation.