Reflections on low-dose radiation, the misconceptions, reality and moving forward

Low dose radiation has been widely accepted by the radiation protection community as presenting a very low risk to human health, if any. Over-conservatism in optimisation principles and regulations have resulted in a disproportionate fear of radiation amongst the general public and government authorities alike, overlooking the great benefits nuclear science and techniques have brought to society as a whole. As such, the World Nuclear Association advocates for a recontextualisation of the radiation hazards with regards to low dose radiation, and a greater awareness as to the absence of any discernible effects associated with it.

The US Nuclear Regulatory Commission radiation protection policy and opportunities for the future

For nearly 50 years, the US Nuclear Regulatory Commission (NRC) has been responsible for the development of radiation protection regulations and guidance for protecting workers, the public and the environment. In 1971, although ALARA was not a regulatory requirement, NRC's predecessor, the Atomic Energy Commission, incorporated the concept of 'as low as is practically achievable' into its general provisions for standards against radiation, Title 10, Code of Federal Regulations (10 CFR) Part 20. In 1975, the NRC codified the phrase 'as low as is reasonably achievable' (ALARA) and the definition of ALARA was broadly consistent with today's definition. Implicit in the ALARA concept is the linear no-threshold (LNT) dose-response relationship. The NRC acknowledges that a bifurcation between the public's concern with radiation exposure and the perspectives of many in the scientific community to eliminate LNT-based regulations exists. NRC understands that the LNT basis for ALARA (i.e. that the stochastic effects of radiation do not have a low dose threshold) is not accepted by all individuals, but the LNT theory continues to serve as the basis of its regulatory approach, which is derived directly from the recommendations of national and international expert bodies. Over the years, NRC and other Federal agencies have been petitioned to revise the basis for their radiation protection policy. This article presents an overview of what NRC has done and explores opportunities for maintaining the right balance between the potential risks and benefits of radiation in establishing radiation protection policy.

Quantitative assessment of provability of radiation-related cancers considering unavoidable existence of unadjusted risk factors

The attribution of stochastic effects to exposure to ionizing radiation has been qualitatively discussed by introducing two distinct concepts of provability and probability. This study aims to develop a method of quantitatively assessing the provability of radiation-related cancers. To this end, the 'minimum provable dose' (MPD) was developed and applied to actual cancer mortality in Japan. The background lifetime risk of cancer mortality was calculated for the esophagus, stomach, colon, liver, lungs, skin, breasts, ovaries, bladder, and bone marrow as well as the age-specific risk coefficients reproducing those given in the 2007 Recommendations of the International Commission on Radiological Protection (ICRP). Comparing the relative ratio of MPDs, which was defined herein as the 'provability index' (PI), we quantitatively ranked radiation-related cancers for different tissues and organs predicated on provability for ages of 10, 30, 50, and 0-85+  years at exposure. We discuss the radiological protection of male emergency workers focusing on cancers highly prioritized according to the ranking (i.e. colon, bone marrow, and bladder). The present study proposed the system to quantitatively evaluate the level of radiological protection taking into account the variations of the background cancer risk on the provability of radiation-related cancers.