Cancer risk was studied in 10,552 Swedish hyperthyroid patients treated with 131I between 1950 and 1975. Patients were followed for an average of 15 years (range 1-35 years) and were matched with the Swedish Cancer Register (SCR) and the Swedish Cause of Death Register (SCDR). The overall standardized incidence ratio (SIR) was 1.06 [95% confidence interval (CI) = 1.01-1.11], and the overall standardized mortality ratio (SMR) was 1.09 (95% CI = 1.03-1.16). The stomach was the only site for which cancer risk increased over time (p < 0.05) and with increasing activity of 131I administered (p = not significant). No increased incidence of leukemia was found, which adds further support to the view that a radiation dose delivered gradually over time is less carcinogenic than the same total dose received over a short time. A possible excess owing to radiation was suggested only for stomach cancer.
Health agencies throughout the world have evaluated the safety of irradiated foods by considering the likelihood that irradiation would induce radioactivity, produce toxic radiolytic products, destroy nutrients, or change the microbiological profile of organisms in the food. After years of study, researchers have concluded that foods irradiated under the proper conditions will not produce adverse health effects when consumed.
Epidemiologic data from underground miners confirm that radon decay products are carcinogenic, but evidence for the quantitative risks of these exposures, especially for indoor air, is less conclusive. Experimental animal studies, in conjunction with dosimetric modeling and molecular-cellular level studies, are particularly valuable for understanding the carcinogenicity of human radon exposures and the modifying effects of exposure rate, the physical characteristics of the inhaled decay products, and associated exposures to such agents as cigarette smoke. Similarities in animal and human data, including comparable lung cancer risk coefficients, tumor-related dosimetry, and tumor pathology, presently outweigh their differences. The animal models, therefore, appear to be reasonable substitutes for studying the health effects of human radon exposures.
A Test of the Linear-No-Threshold Model of Radiation Carcinogenesis
Bernard L. Cohen and , Graham A. Colditz Radiation and Public Perception
Chapter 6, pp 67–77
Pub Date : May, 1995
American Chemical Society
The linear-no-threshold theory used to estimate the cancer risk of low level radiation from the known risks of high-level radiation is tested by studying the variation of lung cancer mortality rates (m) with average exposure to radon (r) in various U.S. states and counties. The data indicate a strong tendency form to decrease with increasing r, in sharp contrast to the theory prediction of a strong increase of m with increasing r. To explain this discrepancy by a strong tendency for areas of high radon to have low smoking prevalence, and vice versa, would require almost 100% negative correlation between radon and smoking, whereas current information indicates a correction of only a few percent. Several other possible explanations for the discrepancy are explored, but none seem to be effective in substantially reducing it.
Some of the most common units, concepts, and models in use today dealing with radiation exposures and their associated risks will be presented. Discussions toward a better understanding of some of the basic difficulties in quantifying risks associated with low levels of radiation will be presented. The main thrust of this chapter will be on laying a foundation for better understanding and appreciation of the chapters to follow.
Editor(s): Jack P. Young1, Rosalyn S. Yalow2
Publication Date (Print): May 05, 1995
American Chemical Society
Radiation and Public Perception
Public Perception of Radiation Risks
Basic Units and Concepts in Radiation Exposures
Department of Energy Radiation Health Studies
The U.S. Transuranium and Uranium Registries
Lung Cancer Mortality and Radon Exposure
Evidence of Cancer Risk from Experimental Animal Radon Studies
Evaluating the Safety of Irradiated Foods
Cancer Incidence and Mortality after Iodine-131 Therapy for Hyperthyroidism
The Genetic Effects of Human Exposures to Ionizing Radiation
Studies of Children In Utero during Atomic Bomb Detonations
Cancer Risks among Atomic Bomb Survivors
A Health Assessment of the Chernobyl Nuclear Power Plant Accident
Health Studies of U.S. Women Radium Dial Workers
Evaluating Health Risks in Communities near Nuclear Facilities
Health Effects on Populations Exposed to Low-Level Radiation in China
Health and Mortality among Contractor Employees at U.S. Department of Energy Facilities
Does Nuclear Power Have a Future?
Science, Society, and U.S. Nuclear Waste
The evolution of advanced civilization has yielded works of art and science, complex financial and political systems, and technology-driven societies such as the United States. Yet as the sophistication of these societies has increased, human self-perception has diminished. One consequence of this suppressed self-image has been a growing distrust of science and certain technologies such as nuclear energy and radiation. This apprehension has been nurtured by the news and entertainment media and has partially compromised the benefits that these technologies offer. Realization of these benefits requires a restoration of self-confidence in our ability to use technologies beneficially.
In 1989 the then Soviet government requested that the International Atomic Energy Agency (IAEA) assess the steps it took to protect the health of villagers in areas surrounding the site of the 1986 Chernobyl nuclear power plant accident. The International Chernobyl Project (ICP) performed the assessment. “Task 4” of the ICP studied sample populations from three Soviet republics. Teams of physicians from several nations visited seven “control” (uncontaminated) and six “contaminated” villages to obtain in-depth medical histories on and to perform extensive physical examinations of over 1300 persons. No adverse health effects directly attributable to radiation were found by Task 4. Many of the villagers demonstrated increased stress and anxiety related to the accident, but no significant differences were seen between residents of the contaminated and the control villages. However, a high incidence of hypertension, poor dental health, and obesity in the population samples from all the villages did exist. Although it was too early to see increases in leukemia and solid tumors in the populations examined, the authors expect that there will be increases in the incidence of both these types of cancers over the next several decades.
Water is everywhere. One might think water from the tap that is clear and tastes all right is pure, but it is not enough so for laboratory use. Water picks up pollutants when it touches the ground?s surface and minerals when it permeates the ground. It also contains dissolved gases and dirt from the air. Contaminants that might be found in water include particulates, dissolved inorganic solids and gases, dissolved organics, micro-organisms, and pyrogens. Standards for laboratory pure water are published by several scientific, medical, or other groups. The National Committee for Clinical Laboratory Standards, which is now known as the Clinical and Laboratory Standards Institute, lists four categories, from the purest to water with certain contaminants removed. When the type of water needed is determined, a process can be set up to create it. They include reverse osmosis, filtration, and electrodialysis. The various processes are explained, and there is an accompanying checklist for design process, flow rates, distribution, distribution piping, storage tank, water hardness classifications, filtration, commissioning, pipe materials, and validation. Attached is a water pipe sizing table.
The objective of this Report is to review the current state-of-knowledge of uncertainties in internal dose assessments, including uncertainties in the measurements that are used to perform these assessments. In a previously published report (NCRP, 2007), the current state-of-knowledge of uncertainties in external radiation measurements and dosimetry was reviewed. The scope of this Report is limited to internal radiation exposure. It is intended to be used primarily by radiation dosimetrists, including health physicists, radiation protection professionals, and medical physicists who need to evaluate of the uncertainties in estimates of absorbed doses. The scope of application ranges from the improvement of routine dosimetry procedures to the reconstruction of individual doses in epidemiological studies to treatment planning for therapeutic nuclear medicine. Sections 1 to 4 are descriptive in nature and do not present a high level of technical difficulty and so may provide useful knowledge to health physicists, radiation protection professionals, and medical physicists who are involved in the assessment of doses from internal sources of radiation. Sections 5 to 10 are more technical and address issues of interest to health physicists involved in the assessment of uncertainties. The appendices, in which details of various methods and models are presented, are meant to be read by those scientists interested in a particular issue.