The linear no-threshold (linear-non-threshold) model is a dose-response model that has long served as the foundation of the international radiation protection framework, which includes the Canadian regulatory framework. Its purpose is to inform the choice of appropriate dose limits and subsequent as low as reasonably achievable requirements, social and economic factors taken into account. The linear no-threshold model assumes that the risk of developing cancer increases proportionately with increasing radiation dose. The linear no-threshold model has historically been applied by extrapolating the risk of cancer at high doses (>1,000 mSv) down to low doses in a linear manner. As the health effects of radiation exposure at low doses remain ambiguous, reducing uncertainties found in cancer risk dose-response models can be achieved through in vitro and animal-based studies. The purpose of this critical review is to analyze whether the linear no-threshold model is still applicable for use by modern nuclear regulators for radiation protection purposes, or if there is sufficient scientific evidence supporting an alternate model from which to derive regulatory dose limits.
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http://dx.doi.org/10.1097/HP.0000000000001060 | DOI Listing |
J Hazard Mater
December 2024
Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Mumbai 400094, India. Electronic address:
Arsenic (As) is a potent carcinogen that enters the human food chain mainly through rice, which is one of the staple food crops worldwide. During February 2022, a market survey was conducted and 500 samples of rice grains were collected across 41 different locations in Mumbai/Navi-Mumbai. On the basis of grain As-accumulation, samples were grouped into three categories including low- (0-30 ng g DW), medium- (31-70 ng g DW) or high- (>71 ng g DW).
View Article and Find Full Text PDFDose Response
December 2024
Canadian Nuclear Laboratories - Retired, Chalk River, ON, Canada.
The Hiroshima/Nagasaki (H/N) studies by the Radiation Effect Research Foundation have not shown increased leukaemia for acute doses below 200 milli-gray (mGy). By contrast the INWORKS study of leukaemia in workers stated: "This study provides strong evidence of positive associations between protracted low-dose radiation exposure and leukemia". The INWORKS study also claimed increased leukaemia, not including Chronic Lymphocytic Leukaemia, at cumulative occupational doses of less than 100 mGy.
View Article and Find Full Text PDFAnimals (Basel)
November 2024
Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
Relative humidity (RH) is measured in vivaria with a broad range to accommodate seasonal fluctuations. It is assumed that measurements in the room (macroenvironment) reflect those in the cage (microenvironment). However, there is limited data comparing RH in the macroenvironment to the microenvironment and how the mice may be affected by variations in RH that fall within husbandry recommendations.
View Article and Find Full Text PDFDose Response
November 2024
Department of Biomedical Science and Technology, Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
The linear no-threshold (LNT) model, which has been used for radiation protection purposes, was developed based on the assumption that exposure to even a small amount of radiation may cause cancer. However, although it is known in carcinogenesis that there is variation in radiation sensitivity among individuals, the LNT model does not adequately consider radiosensitive subgroups. In this paper, we represent susceptibility to contract cancer by radiation exposure by means of the threshold of a dose-response function, introduce an assumption that the thresholds are random to represent the variation of the radiosensitivity among individuals in a susceptible subgroup.
View Article and Find Full Text PDFRadiat Environ Biophys
October 2024
Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, Warszawa, 00-662, Poland.
The presented paper describes the problem of human health in regions with high level of natural ionizing radiation in various places in the world. The radiation adaptive response biophysical model was presented and calibrated for the special case of constant dose-rate irradiation. The calibration was performed for the data of residents of several high background radiation areas, like Ramsar in Iran, Kerala in India or Yangjiang in China.
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