A Proposal for the Application of Mathematical Models That Accurately Approximate Measured Data to Radiation Protection

Recently, we have proposed a mathematical model, the Whack-A-Mole model (WAM model), which reproduces the dose rate effects observed in genetic effects research experiments in animals and plants such as mice with extremely high accuracy. Since this model can also trace the variation of the effect with time, it is possible to predict the effect under irradiation environments that are difficult to explain the method using DDREF, i.e., in situations such as the space environment where the dose rate fluctuates, and the exposure continues for a long period of time. This model also has the potential to be applied to the prediction of long-term effects in areas affected by nuclear disaster. The WAM model can also be used to the prediction of changes in tumor volume in the fractionated radiation therapy. In Japan, empirical studies for its practical application are currently being conducted in the field of cancer treatment.

Recently, it has also been suggested that the basic concept of the WAM model can be applied to explain the occurrence of chromosome aberrations in peripheral blood lymphocytes and the decrease of unstable aberrations after irradiation. We are now investigating the applicability of the WAM model to chromosome aberrations. If we are able to approximate chromosome aberrations mathematically, we expect to be able to predict changes in the number of chromosome aberrations under conditions of long-term or multiple exposures to relatively high doses, such as astronaut missions, as well as for applications in the field of radiotherapy.

In this way, the newly proposed mathematical models and the concepts behind such models concerning biological effects are becoming more accurate and reflective of actual data, compared to the models and concepts that have been referred for many years in the field of radiation protection. In this presentation, we will take the WAM model as an example, and strongly suggest the incorporation of a new mathematical model in the field of radiation protection that more accurately reflects the actual measured data in addition to the models that have been used for many years in the field of radiation protection and discuss the advantages and disadvantages of adding the new model.