Purpose: This letter suggests a formalism, the medical effective dose (MED), that is suitable for assessing stochastic radiogenic risks in diagnostic medical procedures.
Methods: The MED is derived from radiobiological and probabilistic first principals, including: (1) The independence of radiation-induced biological effects in neighboring voxels at low doses; (2) the linear no-threshold assumption for stochastic radiation injury (although other dose-response relationships could be incorporated, instead); (3) the best human radiation dose-response data currently available; and (4) the built-in possibility that the carcinogenic risk to an irradiated organ may depend on its volume. The MED involves a dose-risk summation over irradiated voxels at high spatial resolution; it reduces to the traditional effective dose when every organ is irradiated uniformly and when the dependence of risk on organ volumes is ignored.
Unlabelled: There are several types of serious nuclear or radiologic emergencies that would require a specialized medical response. Four scenarios of great public health, economic, and psychologic impact are the detonation of a nuclear weapon, the meltdown of a nuclear reactor, the explosion of a large radiologic dispersal device ("dirty bomb"), or the surreptitious placement of a radiation exposure device in a public area of high population density. With any of these, medical facilities that remain functional may have to deal with large numbers of ill, wounded, and probably contaminated people.
View Article and Find Full Text PDFThe monitoring of environmental radiation has been carried out across the United States by the U.S. Environmental Protection Agency's RadNet (formerly the Environmental Radiation Ambient Monitoring System, ERAMS) and the Global Network Program (GNP) of the Environmental Measurements Laboratory (EML), and in the People's Republic of China (PRC) by their National Radioactivity Contamination Monitoring System (NRCMS).
View Article and Find Full Text PDFThe National Institutes of Health (NIH) comprise the largest single source of funding in the world for the support of biomedical research. Much of the work of the NIH focuses on the elucidation of fundamental biophysical, biochemical, and biologic aspects of the molecular, cellular, and tissue processes underlying both healthy and diseased states of biologic systems and on the development of cures for the latter. In 2000, the National Institute of Biomedical Imaging and Bioengineering (NIBIB) was created with a somewhat different focus: Rather than concentration on a specific organ system or category of disease, the primary objective of the NIBIB is the advancement of technologies and tools that contribute to all aspects of biomedical research and health care delivery, especially in the imaging sciences and bioengineering.
View Article and Find Full Text PDFMedical images are created by detecting radiation probes transmitted through or emitted or scattered by the body. The radiation, modulated through interactions with tissues, yields patterns that provide anatomic and/or physiologic information. X-rays, gamma rays, radiofrequency signals, and ultrasound waves are the standard probes, but others like visible and infrared light, microwaves, terahertz rays, and intrinsic and applied electric and magnetic fields are being explored.
View Article and Find Full Text PDFFederal and state regulatory agencies that are concerned with issues of environmental management have adopted approaches toward policy-making that are dose- and risk-informed. To that end they (and others) have developed environmental models and computer codes to mimic the transport of contaminants along air, water, food-chain, and related pathways for estimating potential exposures, doses, and risks to individuals, populations, and ecosystems. Their calculations commonly find application in the planning of remediation, and thereafter in the demonstration of compliance with federal and state cleanup standards.
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