Cancer complexity and radiation protection.

Management of radiological risks typically encountered in environmental and occupational settings is challenging because of uncertainties in the magnitude of the risks and the benefits of risk reduction. In practice, radiation dose instead of risk is measured. However, the relationship between dose and risk is not straightforward because cancer (the major health effect of concern at low doses) is a disease of complexity. Risks at small doses (defined as less than 100 mSv) can never be known exactly because of the inherent uncertainties in cancer as a complex disease. Tumors are complex because of the nonlinear interactions that occur among tumor cells and between the tumor and its local tissue environment. This commentary reviews evidence for cancer complexity and what complexity means for radiation protection. A complexity view of cancer does not mean we must abandon our current system of protection. What it does mean is that complexity requires new ways of thinking about control of cancer-the ideas that cancers can occur without cause, cancers behave unpredictably, and calculated cancer risks following small doses of radiation are highly uncertain.

The LNT Debate in Radiation Protection: Science vs. Policy.

There is considerable interest in revisiting LNT theory as the basis for the system of radiation protection in the US and worldwide. Arguing the scientific merits of policy options is not likely to be fruitful because the science is not robust enough to support one theory to the exclusion of others. Current science cannot determine the existence of a dose threshold, a key piece to resolving the matter scientifically. The nature of the scientific evidence is such that risk assessment at small effective doses (defined as <100 mSv) is highly uncertain, and several policy alternatives, including threshold and non-linear dose-response functions, are scientifically defensible. This paper argues for an alternative approach by looking at the LNT debate as a policy question and analyzes the problem from a social and economic perspective. In other words, risk assessment and a strictly scientific perspective are insufficiently broad enough to resolve the issue completely. A wider perspective encompassing social and economic impacts in a risk management context is necessary, but moving the debate to the policy and risk management arena necessarily marginalizes the role of scientists.

The dose from Compton backscatter screening.

Systems based on the detection of Compton backscattered X rays have been deployed for screening personnel for weapons and explosives. Similar principles are used for screening vehicles at border-crossing points. Based on well-established scattering cross sections and absorption coefficients in conjunction with reasonable estimates of the image contrast and resolution, the entrance skin dose and the dose at a depth of 1 cm can be calculated. The effective dose can be estimated using the same conversion coefficients as used to convert exposure measurements to the effective dose. It is shown that the effective dose is highly dependent on image resolution (i.e. pixel size).The effective doses for personnel screening systems are unlikely to be in compliance with the American National Standards Institute standard NS 43.17 unless the pixel sizes are >4 mm. Nevertheless, calculated effective doses are well below doses associated with health effects.

Policy decision-making under scientific uncertainty: radiological risk assessment and the role of expert advisory groups.

Standard-setting agencies such as the U.S. Nuclear Regulatory Commission and the U.S. Environmental Protection Agency depend on advice from external expert advisory groups on matters of public policy and standard-setting. Authoritative bodies including the National Research Council and the National Council on Radiation Protection and Measurements provide analyses and recommendations that enable the technical and scientific soundness in decision-making. In radiological protection the nature of the scientific evidence is such that risk assessment at radiation doses typically encountered in environmental and occupational settings is highly uncertain, and several policy alternatives are scientifically defensible. The link between science and policy is problematic. The fundamental issue is the failure to properly consider risk assessment, risk communication, and risk management and then consolidate them in a process that leads to sound policy. Authoritative bodies should serve as unbiased brokers of policy choices by providing balanced and objective scientific analyses. As long as the policy-decision environment is characterized by high scientific uncertainty and a lack of values consensus, advisory groups should present unbiased evaluations of all scientifically plausible alternatives and recommend selection criteria that decision makers can use in the policy-setting process. To do otherwise (e.g., by serving as single position advocates) weakens decision-making by eliminating options and narrowing discussions of scientific perspectives. Understanding uncertainties and the limitations on available scientific information and conveying such information to policy makers remain key challenges for the technical and policy communities.

Heart disease awareness among college students.

The purpose of this research was to explore college students' attitudes about heart disease risks and preventive strategies. The survey population consisted of students enrolled in selected lecture courses at Arizona State University. A total of 1481 surveys were used in data analysis. Respondents indicated a lower perception of heart disease risk for women than for men, and a majority of students incorrectly believed that breast cancer is a more significant health concern for women than heart disease. Respondents in most ethnic groups believed that whites are most at risk for developing heart disease. Students overall had relatively low levels of knowledge about heart disease and its risk factors compared to other health issues, such as sexually transmitted diseases (STDs) and psychological disorders. The results suggest that educational intervention is necessary to increase college students' knowledge about heart disease; and, in particular, efforts need to be made to raise awareness about heart disease among women and minorities. Guidelines for future educational intervention must address common misconceptions about which demographic groups are at risk for developing heart disease and address gaps in knowledge that young people have regarding heart disease prevention.

The role of advisory organizations in ionizing radiation protection science and policy: a proposal.

Funding for radiation protection science and policy has been in decline for more than a decade. Agencies that set policies and standards for radiation protection depend on external expert groups for advice, and unless the funding situation is stabilized, the ability of these advisory organizations to provide timely advice will be compromised. This paper examines the history of radiation protection policy in the United States, reviews the funding patterns of international and national radiation protection advisory bodies, and suggests recommendations for assuring that radiological and radiation protection science remains an important part of the nation's public health policy agenda. Five major advisory organizations are the focus of this paper--ICRP, ICRU, NCRP, National Research Council BEIR Committees, and UNSCEAR. The recommendations developed in this paper address the following issues: (1) the need to coordinate activities among national and international advisory bodies in order to minimize overlap of work scope and ensure comprehensive coverage of major radiation protection issues; (2) the need to reevaluate activities and operations of advisory groups in the context of an ever-changing radiation protection landscape; and (3) the need to establish the NCRP as the major federal advisory organization for radiation protection in the United States and to stabilize funding through Congressional appropriations.

Restructuring nuclear regulations.

Nuclear regulations are a subset of social regulations (laws to control activities that may negatively impact the environment, health, and safety) that concern control of ionizing radiation from radiation-producing equipment and from radioactive materials. The impressive safety record among nuclear technologies is due, in no small part, to the work of radiation safety professionals and to a protection system that has kept pace with the rapid technologic advancements in electric power generation, engineering, and medicine. The price of success, however, has led to a regulatory organization and philosophy characterized by complexity, confusion, public fear, and increasing economic costs. Over the past 20 years, regulatory costs in the nuclear sector have increased more than 250% in constant 1995 U.S. dollars. Costs of regulatory compliance can be reduced sharply, particularly when health and environmental benefits of risk reduction are questionable. Three key regulatory areas should be closely examined and modified to improve regulatory effectiveness and efficiency: a) radiation protection should be changed from a risk-based to dose-based system; b) the U.S. government should adopt the modern metric system (International System of Units), and radiation quantities and units should be simplified to facilitate international communication and public understanding; and c) a single, independent office is needed to coordinate nuclear regulations established by U.S. federal agencies and departments.