Radiation Protection Philosophy Research Articles

Conservation of “Cause-Effect” by using Integrated Individual Radiation Dosestowards Standardization of Epidemiology Health-Risk Estimates of Nuclear/Radiation Workers

Major efforts have been in progress over the past few decades worldwide on applying low dose/low dose rate ionizing radiation exposures to epidemiological studies of public and in particular radiation workers to estimate radiation health risks to either further support the linear no-threshold (LNT) hypothesis or the hormesis model or any other acceptable models [1,2]. This is in fact the main challenging issue in the practice of present radiation protection philosophy for protection of workers, public and the environment in ionizing radiation applications. Presently, “occupational exposure” in the system of dose limitation and epidemiology studies of workers are only based on radiation doses received during radiation work with no consideration of any doses received from other sources such as chronic natural background (NBG) radiation.

PRUDENCE AND CONSERVATISM IN RADIATION PROTECTION: A CASE STUDY.

Prudence is a cornerstone of radiation protection philosophy. However, whilst the concept is clearly valid at the level of principle, it is nonetheless necessary to ask 'How should prudence be applied in the context of various practical situations.' This is perhaps particularly important where exposures are low-within the range of natural background, where changes in the level of protection will have no meaningful impact whatsoever on the overall exposure level of any individual. The concept of prudence is applied at a 'top tier' level through the application of the Linear No Threshold hypothesis. In day-to-day protection considerations, including many types of dose assessments, the concept of prudence has translated into the need to take a conservative approach. This paper considers the combined impact of accumulated layers of conservatism, using the example of clearance as a case study. It concludes that doses actually resulting from the clearance process are typically more than two orders of magnitude below the internationally agreed objective of 'some tens of µSv y-1', which was itself established on the basis of considerable prudence. The implications of this outcome are discussed.

Radioprotective Role of Some Bacteria Belonging to Actinomycetales against Gamma Irradiation-Induced Oxidative Stress in Male Albino Rats

Background: radiation protection concepts and philosophy have been evolving over the past several decades. The inadvertent exposure of human from various source of radiation causes ionization of molecules, setting off potentially damaging reactions via free radicals production. Development of radioprotectants and mitigators is the therapeutic approach to ameliorate the negative health impact of radiation exposure. The majority of substances with biological activity used in medicine are produced by actinomycetes and fungi. Aim: the aim of the present study is to evaluate the radioprotective role of the antimicrobial active metabolite of Streptomyces atrovirens Rahman as antioxidant against gamma irradiation that induced some biochemical alterations in rats. Material and Methods: animals were pretreated with antimicrobial active metabolite of Streptomyces atrovirens Ab1 using suitable stomach tube for two weeks prior to radiation exposure. The levels of malondialdhyde (MDA), glutathione content (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutamic oxaloacetic transaminase (ALT), glutamic aspartate transaminase (AST), alkaline phosphatase (ALP) and gamma glutamyl transferase (GGT) activities, also total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), and low density lipoprotein cholesterol (LDL- C) were estimated. Results: the results revealed that exposure to ionizing radiation resulted in significant elevation in the levels of MDA content, ALT, AST, ALP and GGT activities and concentration of TC, TG and LDL-C, meanwhile, showed significant depletion in GSH content and SOD, CAT and GPx activities and HDL-C concentration. Conclusion: it could be concluded that, the administration of the antimicrobial active metabolite of Streptomyces atrovirens Ab1 pre-whole body gamma irradiation resulted in sufficient amelioration against radiation effects on the biochemical aspects examined in the present study.

Low-level radiation exposures: Time to revisit linear no-threshold concept

The concepts of LNT (Linear No-Threshold) and the resulting ALARA (As Low As Reasonably Achievable) used for radiological protection have been stumbling blocks for public acceptability of nuclear power. Often, public get confused and easily get exploited by interested people. The application of this concept has perhaps resulted in a more harmful phenomenon now known as radiophobia. Over the years, LNT has become the corner stone of radiation protection philosophy for the international organizations like ICRP, UNSCEAR etc. which is followed by all national regulators. The genesis of these theories is the cellular level findings of half a century back. Most of these are findings at high dose levels in macro systems and extrapolated to low dose. It is time that international radiation safety organizations revisit the assumptions and have a more pragmatic approach towards these abstract concepts in the light of new findings. The article reviews the evolution of LNT hypothesis and the basis for LNT, examines the possibility that there might be a threshold dose, below which there would be no radiation-related cancer risk. Evidences against LNT and the possible existence of a threshold dose are reviewed. The article concludes that this is definitely time to have a re-look of the corner stone concepts in radiation protection philosophy.

World high background natural radiation areas: Need to protect public from radiation exposure

Abstract Highlights of findings on radiological measurements, radiobiological and epidemiological studies in some main world high background natural radiation (HBNR) areas such as in Brazil, China, India and Iran are presented and discussed with special regard to remediation of radiation exposure of inhabitants in such areas. The current radiation protection philosophy and recommendations applied to workers and public from operation of radiation and nuclear applications are based on the linear non-threshold (LNT) model. The inhabitants of HBNR and radon prone areas receive relatively high radiation doses. Therefore, according to the LNT concept, the inhabitants in HBNR areas and in particular those in Ramsar are considered at risk and their exposure should be regulated. The HBNR areas in the world have different conditions in terms of dose and population. In particular, the inhabitants in HBNR areas of Ramsar receive very high internal and external exposures. This author believes that the public in such areas should be protected and proposes a plan to remedy high exposure of the inhabitants of the HBNR areas of Ramsar, while maintaining these areas as they stand to establish a national environmental radioactivity park which can be provisionally called “Ramsar Research Natural Radioactivity Park” (RRNRP). The major HBNR areas, the public exposure and the need to remedy exposures of inhabitants are reviewed and discussed.

Radiation protection in Australia: a thirty year perspective

This review charts the changes in radiation protection philosophy, regulation and practice over the thirty year period 1977-2007. During this time there have been substantial changes both internationally and in Australia. Medical physicists have been involved, and continue to be involved, in all aspects of radiation protection in medicine at a national, State and hospital level.

Protective actions in the late phase--intervention criteria and decision-making.

Major countermeasures in the late phase of a nuclear or radiological accident where long-lived radionuclides have been dispersed in the environment are relocation/resettlement, foodstuff restrictions, agricultural countermeasures and clean-up of contaminated areas. There has essentially been a broad acceptance internationally of the principles for their introduction, but it has not been possible to reach an agreement for the purpose of defining a net benefit based upon the exact weighting to be attached to each of the attributes influencing the decision on intervention, e.g. socio-psychological attributes. Optimisation of protection, i.e. maximising the net benefit, is not a question of developing radiation protection philosophy to fully include socio-psychological factors but rather to include these factors--in parallel with the radiological protection factors--in cooperation between radiation protection experts and e.g. experts in social and psychological sciences under the responsibility of the decision-maker, who will take the final decision on the introduction of long-term countermeasures.

Risk versus benefit in diagnostic radiology

The risks from the use of ionizing radiation in diagnostic radiology have been established, almost from the time at which X-rays were first discovered. The fundamental objectives of radiation protection are to avoid the occurrence of deterministic injuries and to minimize the risk of stochastic effects. The basic principles of radiation protection philosophy are justification and optimization. These principles are applied to ensure that diagnostic radiology procedures are safe. Implicit in the application of these principles is that the benefit/risk ratio is evaluated for all procedures. In practice, very little scientific work has been performed in this area, with the main exception of screening mammography. This article describes some of the problems in applying the justification principal in diagnostic radiology. An example calculation for screening mammography is given.

Radiotherapy of childhood haemangiomas: from active treatment to radiation risk estimates.

Childhood skin haemangiomas have been subjected to many different kinds of active treatment. From the beginning of the twentieth century and up to 1960-1970, radiotherapy maintained a dominating place in this treatment, although during the latter part of this period its role was more and more questioned. Starting in 1958, I felt that, based on the scientific literature and on my own observations at Malmö University Hospital, active therapy including radiotherapy should be abandoned since it had turned out to be unnecessary and, furthermore, could be harmful. This viewpoint resulted from an increased knowledge of the natural history of the disease. I then got the possibility to establish a follow-up study cohort at Sahlgrenska University Hospital in Göteborg with the aim of gaining information on early and late radiation effects following childhood radiotherapy. Later, the study cohort was enlarged by pooling with similar cohorts originating from Stockholm and Paris. A summary of the results of the epidemiological studies is also presented here. This historical overview reflects half a century of radiation therapy and radiation protection philosophy. It contains a basic message pointing to the value of proper and reliable collection of medical data and to the importance of local, regional and national registers, to preserve the information.

Alternative goals and policy mechanisms for radiation protection.

For decades, radiation protection philosophy and practice have been the domain of professionals trained in the physical and medical sciences. Radiation protection policy was formulated and implemented largely without consultation with or participation by other professional disciplines or the general public. Although, from a public health standpoint, past radiation protection efforts have worked well, there are growing signs that the public has lost confidence in the radiation risk management system as currently configured. This paper draws on perspectives of political science, social psychology, economics, and decision analysis to analyze the limitations of the current radiation protection regime and to suggest alternatives for enhancing public trust and improving efficacy.

Control of low-level radiation exposure: what is the problem and how can it be solved?

The carcinogenic risks of exposure to low-level ionizing radiation used by ICRP have been challenged as being, at the same time, both too high and too low. This paper explains that the epidemiological evidence will always be limited at low doses, so that understanding the cellular mechanisms of carcinogenesis is increasingly important to assess the biological risks. An analysis is then given of the reasons why the challenges to ICRP, especially about the linear nonthreshold response model, have arisen. As a result of considering the issues, the Main Commission of ICRP is now consulting on a revised, simpler approach based on an individual oriented philosophy. This represents a potential shift by the Commission from the past emphasis on societal-oriented criteria. These proposals have been promulgated through IRPA, and an open literature publication was published in the Journal of Radiological Protection in June 1999. On the basis of comments received and the observations presented at the IRPA 10 Conference, the Commission will begin to develop the outline of the next recommendations. It is now more than 10 y since ICRP distributed, for comment, a draft of what was to become the publication of the 1990 recommendations. The Commission plans to develop its new recommendations on a time scale of the next 4 or 5 y. In this paper, many of the issues that will need to be addressed in the development of the recommendations will be identified. These issues will cover biological effects, dosimetric quantities, and the establishment of those levels of dose at which different protection requirements will be put into place. Concepts of exclusion and exemption will need to be clarified as well as the meaning of how to achieve what the proposal identifies as "as low as reasonably practicable." Finally, the Commission has decided to develop an environmental radiation protection philosophy that will need to be developed as part of the new recommendations.

Issues in the control of low‐level radiation exposure*

The carcinogenic risks of exposure to low level ionizing radiation used by the International Commission on Radiation Protection (ICRP) have been challenged as being, at the same time, both too high and too low. This paper explains that the epidemiological evidence will always be limited at low doses, so that understanding the cellular mechanisms of carcinogenesis is increasingly important to assess the biological risks. An analysis is then given of the reasons why the challenges to ICRP, especially about the linear non‐threshold response model, have arisen. As a result of considering the issues, the Main Commission of ICRP is now consulting on a revised, simpler, approach based on an individual oriented philosophy. This represents a potential shift by the Commission from the past emphasis on societal‐oriented criteria. These proposals have been promulgated through the International Radiation Protection Association (IRPA) and an open literature publication was published in the Journal of Radiological Protection 1 in June 1999. On the basis of comments received and the observations presented at the IRPA 10 Conference, the Commission will begin to develop the outline of the next Recommendations. It is now more than ten years since ICRP distributed, for comment, a draft of what was to become the publication of the 1990 Recommendations. The Commission plans to develop its new Recommendations on a time scale of the next four or five years. In this paper, many of the issues that will need to be addressed in the development of the recommendations will be identified. These issues will cover biological effects, dosimetric quantities and the establishment of those levels of dose at which different protection requirements will be put into place. Concepts of exclusion and exemption will need to be clarified as well as the meaning of how to achieve what the proposal identifies as ‘As Low as Reasonably Practicable’ (ALARP). Finally, the Commission has decided to develop an environmental radiation protection philosophy that will need to be developed as part of the new Recommendations.

Will Radiation Control Be by Reason Or Regulation?

Following a very brief review of the development of our present radiation-protection philosophy, attention is directed to what the author sees as current problems. The only prognostication will be that at least certain of the problems outstanding or developing today will be among those that will have to be addressed in the coming four decades. For the past six decades, the major effort has been the development of the science and philosophy of radiation biology and its application to protection against radiation hazards, whether real or imagined. For three decades there has been public concern about radiation generally, the core of the problem being inadequate education of the public and the media on the subject. For a little over one decade, there has been rapidly developing growth of tort litigation generally, involving ionizing radiation in particular. These are the three major lines of attention in the radiation-protection area today; between two of them there are already some of the aspects of "the arena." Behind all three lies an overwhelming lack of understanding by, and education of, the public, which shows mostly in the public fetish for absolute safety which, of course, cannot be. These must be the major concerns of the radiation-protection community in the coming four decades.

Radiation protection philosophy: bioethical problems and priorities.

The evolution of radiation protection philosophy over the past thirty years calls attention to an urgent need to review and revise current radiation control programs with respect to the ethical problems and priorities they reflect. One problem is the environmental crisis-mentality escalating already rising expectations in our affluent society about levels of safety. A second problem is the propriety or impropriety of using cost/benefit/risk quantifications in setting priorities in public health protection. A threefold ethical justification for risk-assessment methodology challenges our government regulatory agency system as presently chartered and operationally conducted.

Book reviewN.C.R.P. REPORT, No. 43, 1975. Review of the Current State of Radiation Protection Philosophy. (Recommendations of the National Council on Radiation Protection and Measurement), pp. v + 50.

Book reviewN.C.R.P. REPORT, No. 43, 1975. Review of the Current State of Radiation Protection Philosophy. (Recommendations of the National Council on Radiation Protection and Measurement), pp. v + 50.