Data have been collected and physical and statistical models have been constructed to estimate unknown occupational radiation doses among 90,000 members of the U.S. Radiologic Technologists cohort who responded to a baseline questionnaire during the mid-1980s. Since the availability of radiation dose data differed by calendar period, different models were developed and applied for years worked before 1960, 1960- 1976 and 1977-1984. The dose estimation used available film-badge measurements (approximately 350,000) for individual cohort members, information provided by the technologists on their work history and protection practices, and measurement and other data derived from the literature. The dosimetry model estimates annual and cumulative occupational badge doses (personal dose equivalent) for each technologist for each year worked from 1916 through 1984 as well as absorbed doses to organs and tissues including bone marrow, female breast, thyroid, ovary, testes, lung and skin. Assumptions have been made about critical variables including average energy of X rays, use of protective aprons, position of film badges, and minimum detectable doses. Uncertainty of badge and organ doses was characterized for each year of each technologist's working career. Monte Carlo methods were used to generate estimates of cumulative organ doses for preliminary cancer risk analyses. The models and predictions presented here, while continuing to be modified and improved, represent one of the most comprehensive dose reconstructions undertaken to date for a large cohort of medical radiation workers.

The US Environmental Protection Agency (USEPA) is the primary federal agency responsible for promulgating regulations and policies to protect people and the environment from ionizing radiation. Currently, the USEPA uses the linear no-threshold (LNT) model to estimate cancer risks and determine cleanup levels in radiologically contaminated environments. The LNT model implies that there is no safe dose of ionizing radiation; however, adverse effects from low dose, low-dose rate (LDDR) exposures are not detectable. This article (1) provides the scientific basis for discontinuing use of the LNT model in LDDR radiation environments, (2) shows that there is no scientific consensus for using the LNT model, (3) identifies USEPA reliance on outdated scientific information, and (4) identifies regulatory reliance on incomplete evaluations of recent data contradicting the LNT. It is the time to reconsider the use of the LNT model in LDDR radiation environments. Incorporating the latest science into the regulatory process for risk assessment will (1) ensure science remains the foundation for decision making, (2) reduce unnecessary burdens of costly cleanups, (3) educate the public on the real effects of LDDR radiation exposures, and (4) harmonize government policies with the rest of the radiation scientific community.

These findings illustrate the importance of including WRX doses in retrospective epidemiological studies of radiation workers, especially if photofluorographic chest X-rays were performed and occupational exposure to ionizing radiation is low.

In Pennsylvania on February 16, 2006, a New York City resident collapsed with rigors and was hospitalized. On February 21, the Centers for Disease Control and Prevention and the New York City Department of Health and Mental Hygiene were notified that Bacillus anthracis had been identified in the patient's blood. Although the patient's history of working with dried animal hides to make African drums indicated the likelihood of a natural exposure to aerosolized anthrax spores, bioterrorism had to be ruled out first. Ultimately, this case proved to be the first case of naturally occurring inhalational anthrax in 30 years. This article describes the epidemiologic and environmental investigation to identify other cases and persons at risk and to determine the source of exposure and scope of contamination. Because stricter regulation of the importation of animal hides from areas where anthrax is enzootic is difficult, public healthcare officials should consider the possibility of future naturally occurring anthrax cases caused by contaminated hides. Federal protocols are needed to assist in the local response, which should be tempered by our growing understanding of the epidemiology of naturally acquired anthrax. These protocols should include recommended methods for reliable and efficient environmental sample collection and laboratory testing, and environmental risk assessments and remediation.

A model to predict the time weighted exposures to gamma radiation was developed for buildings constructed with structural steel having some contamination from 60Co. Several buildings throughout sixteen city blocks in downtown Taipei were built about ten years ago with this material. These buildings were used for residential, business, and educational purposes with radiation levels ranging from background to five hundred times background. A comprehensive epidemiologic study by the National Yang Ming University Medical School in Taipei is underway to study the effects of this exposure to the building occupants. An evaluation of external radiation exposure was performed using survey instruments and thermoluminescent dosimeters. Exposure data from the survey instruments were used in a computer model developed to calculate cumulative radiation exposure estimates for the epidemiologic research. While the survey instrument data provided radiation levels at a point in time, the thermoluminescent dosimeters were placed in fixed locations and on several volunteers for a period of one month to verify the modeling results. The model itself is a mathematical algorithm that provides estimates with minimum and maximum range values by taking into account differences in the survey data between adults and children, variable occupancy patterns, background radiation, and radioactive decay. Several assumptions (background rates, height adjustment values, and occupancy factors) are easily adjusted to improve the estimated radiation exposures. The model predicted the exposures as measured by the thermoluminescent dosimeters with greater reliability for adults than for children. The differences between the two methods were about 10-15% for the adults and about 60% for the child. This strategy, its advantages, limitations, and its performance against actual thermoluminescent dosimeter measurements are presented.