Protection against to low doses exposure of ionizing radiation

An evolving paradigm (An approximation to what and how much is a low dose)

Abstract

The objective is to address the issue of protecting against situations of exposure to ionizing radiation at low doses and its seemingly intractable dilemma: should people be protected against situations of radiation exposure at low doses?, or conversely, should these exposure situations be ignored or even welcomed? The current status of radiation protection is described for situations involving low radiation doses. The approach includes: (i) a summary of the scientific responses (mainly from radiobiology, radioepidemiology and radiopathology), as well as the recommendations and standards from international organizations; and (ii) a description of the current radiological protection paradigm that explores diverse interpretations, especially those that have generated public fear of low doses of radiation and unjustified sanctions for society.

New developments currently suggested to solve the dilemma are presented, with special emphasis on an international consensus that has been achieved at the highest scientific level within the United Nations system, the United Nations Scientific Committee for the Study of Atomic Radiation (UNSCEAR). The new consensus distinguishes the objective attribution of health effects to situations of retrospective exposure, versus the subjective inference of the potential radiation risk of prospective situations of exposure, and concludes that the increases in the incidence of health effects of populations can not be reliably attributed to low doses exposure situations. Thus, the objective attribution of health effects to low doses exposure situations (whether negative, positive or neutral) falls outside the scope of the relevant sciences due to epistemological limitations. For those situations, science can help providing robustness for subjective inferences of likely outcomes but not for attributing effects.

It is concluded that low dose protection standards should be based on legislative and regulatory decisions rather than on scientific models of radiation response. The evolving international paradigm of radiation protection, based on UN consensus, could provide a basis for solving the enigma of low doses and supporting those decisions. The responsibility rests with legislators and regulators rather than scientists. The moment seems to be ripe: for (i) legislators to use the well-established legal concept of "de minimis non curat lex" and to exclude from the law situations of exposure to low doses that can not be regulated, and (ii) regulators to use the old concept of "minimis non curat prætor" and and exempt from regulations the doses from low-dose exposure situations that do not justify their control.