The Use of Effective Dose as a Radiological Protection Quantity


Draft document: The Use of Effective Dose as a Radiological Protection Quantity
Submitted by Naoki Kubo, Office of Health and Safety, Hokkaido University
Commenting as an individual

The Commission believes that use of the equivalent dose to set dose limits should be discontinued, and that use of the absorbed dose, which is a simpler unit, should be considered. Furthermore, to revisit the fundamentals, the new dose unit may be defined as the particle number of interacted radiation (classified by type of radiation and energy) in a volume element (e.g. organ, tissue and cell aggregate). The dose unit should not be integrated like the equivalent dose unit, which is based on the average absorbed energy and radiation weighting factors. The exposure data with the proposed dose unit are enormous. So, radiation-exposure science must be a big-data science. Radiation-exposure research must involve the use of big data, and there is currently an enormous amount of data available with the proposed dose unit. For this reason, use of the effective dose integrating all organs and tissues should be discontinued.

Of particular importance regarding the effects of radiation on the human body is the functions of free radicals and proinflammatory cytokines. (I agree with the comment by Prof. Brenda Laster from Ben Gurion University.) These induce tissue reactions and stochastic effects due to inflammatory responses and mitochondria injury. The total quantity of free radicals and proinflammatory cytokines generated from ionizing radiation cannot be calculated using the average absorbed energy. Moreover, essential factors to consider when assessing the effects of radiation include the total quantity of free radicals and proinflammatory cytokines, their diffusion, and their transportation throughout the human body.

The proposed dose unit should not be averaged over a volume element (including non-exposed regions). Calculation of the average results in underestimation of the radiation effects. Any underestimation in the radiation effects will misguide those making important decisions concerning human health and the environment. Therefore, the power of radiation must not be underestimated.






























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