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PubMed1988

Application of the ICRP recommendations to revised secondary radiation protection standards.

In 1977, the International Commission on Radiological Protection (ICRP) issued Publication No. 26 containing its recommendations for major changes in the conceptual basis for radiation protection. The new recommendations consider total risk (to the whole body) instead of controlling (critical-organ) risk. Subsequent publications and explanatory statements most useful for providing clarification of the intent of the new recommendations have not resolved practical problems encountered in attempting to apply them to either occupational or public exposures. Some of the problems that still exist in applying these recommendations for estimating doses to members of the public include the following: allowance for age differences within an exposed population group, definition of 50-y dose versus lifetime (70-y) dose, definition of negligible risk levels for individual and collective doses, and derivation of appropriate concentration guidelines. The United States is in the process of adopting the revised recommendations of the ICRP. In addition to adopting versions of the primary radiation protection standards, both the U.S. Nuclear Regulatory Commission and the U.S. Department of Energy have developed draft secondary standards that are similar to the Derived Air Concentration values given by the ICRP. This paper presents a brief history of the development of these revised secondary standards, discusses their technical bases, provides a comparison of them, and discusses their limitations and potential misapplication.

Government Agencies↗
PubMed2006

[Optimizing staff radiation protection in radiology by minimizing the effective dose].

PURPOSE: In the present study the optimization of radiation protection devices is achieved by minimizing the effective dose of the staff members since the stochastic radiation effects correlate to the effective dose. MATERIALS AND METHODS: Radiation exposure dosimetry was performed with TLD measurements using one Alderson Phantom in the patient position and a second phantom in the typical position of the personnel. Various types of protective clothing as well as fixed shields were considered in the calculations. RESULTS: It was shown that the doses of the unshielded organs (thyroid, parts of the active bone marrow) contribute significantly to the effective dose of the staff. Therefore, there is no linear relationship between the shielding factors for protective garments and the effective dose. An additional thyroid protection collar reduces the effective dose by a factor of 1.7 - 3.0. X-ray protective clothing with a 0.35 mm lead equivalent and an additional thyroid protection collar provides better protection against radiation than an apron with a 0.5 mm lead equivalent but no collar. CONCLUSION: The use of thyroid protection collars is an effective preventive measure against exceeding occupational organ dose limits, and a thyroid shield also considerably reduces the effective dose. Therefore, thyroid protection collars should be a required component of anti-X protection.

Health Personnel↗
PubMed2005

Ground-based research with heavy ions for space radiation protection.

Human exposure to ionizing radiation is one of the acknowledged potential showstoppers for long duration manned interplanetary missions. Human exploratory missions cannot be safely performed without a substantial reduction of the uncertainties associated with different space radiation health risks, and the development of effective countermeasures. Most of our knowledge of the biological effects of heavy charged particles comes from accelerator-based experiments. During the 35th COSPAR meeting, recent ground-based experiments with high-energy iron ions were discussed, and these results are briefly summarised in this paper. High quality accelerator-based research with heavy ions will continue to be the main source of knowledge of space radiation health effects and will lead to reductions of the uncertainties in predictions of human health risks. Efforts in materials science, nutrition and pharmaceutical sciences and their rigorous evaluation with biological model systems in ground-based accelerator experiments will lead to the development of safe and effective countermeasures to permit human exploration of the Solar System.

Animals↗
PubMed1981

Comparison between two radiation protective substances in irradiated mice. Effect on splenic haemopoiesis.

The radiation protective action of 2,2'-Dithiobis(N-[(1-adamantyl)-methyl]-acetamidine)-dihyrochloride (S-75) and cysteamine was compared in splenectomized and non-splenectomized mice. Cysteamine was found to have better and more general protection properties. Several indications of a specific effect of S-75 on the spleen were observed. It is suggested that the protection properties of S-75 should be tested in another laboratory animal not having such a marked splenic haemopoiesis as the mouse.

Acetamides↗
PubMed2002

Latin american and Caribbean intercomparison of radiation protection area monitoring instruments.

In December 2000 the International Atomic Energy Agency sponsored an intercomparison of radiation protection area monitoring instruments which was held at the Instituto de Radioproteção e Dosimetria--IRD/CNEN, Rio de Janeiro. Brazil. This intercomparison exercise was aimed at evaluating the ability of some Latin American and Caribbean countries to perform calibrations or such instruments, or have them properly performed by a third party. Nine countries participated in the exercise with 13 portable gamma dose rate monitors. The quantity of interest for the intercomparison was the ambient dose equivalent, H*(10), although some instruments were not designed or calibrated in this quantity. Results were converted to H*(10), whenever necessary. according to the information supplied by each participant. All results for the quantity of interest agree well within 10% of the reference values and the quoted uncertainties.

Calibration↗
PubMed1991

Radiation protection aspects of repairing a highly contaminated tritium cold box.

Radiation protection aspects of modifying a system exposed to tritium gas are discussed. This paper includes a brief discussion of the tritium gas and tritium surface contamination hazards associated with a facility designed to detritiate heavy water. Also described are the protective equipment, dosimetry, instrumentation, contamination control, and decontamination procedures used during welding of tubes that have been exposed to almost pure tritium gas. Absorption of the tritium gas on materials resulted in exposures to high peak concentrations of tritium oxide and high levels of tritium surface contamination (TSC).

Decontamination↗
PubMed2006

Linear-no-threshold is a radiation-protection standard rather than a mechanistic effect model.

The linear-no-threshold (LNT) controversy covers much more than the mere discussion whether or not "the LNT hypothesis is valid". It is shown that one cannot expect to find only one or even the only one dose-effect relationship. Each element within the biological reaction chain that is affected by ionizing radiation contributes in a specific way to the final biological endpoint of interest. The resulting dose-response relationship represents the superposition of all these effects. Till now there is neither a closed and clear picture of the entirety of radiation action for doses below some 10 mSv, nor does clear epidemiological evidence exist for an increase of risk for stochastic effects, in this dose range. On the other hand, radiation protection demands for quantitative risk estimates as well as for practicable dose concepts. In this respect, the LNT concept is preferred against any alternative concept. However, the LNT concept does not necessarily mean that the mechanism of cancer induction is intrinsically linear. It could hold even if the underlying multi-step mechanisms act in a non-linear way. In this case it would express a certain "attenuation" of non-linearities. Favouring LNT against threshold-, hyper-, or sub-linear models for radiation-protection purposes on the one hand, but preferring one of these models (e.g. for a specific effect) because of biological considerations for scientific purposes on the other hand, does not mean a contradiction.

Body Burden↗
PubMed1991

Continuing education in radiation protection: assessment of a one-day course.

A multiple choice questionnaire was completed by 100 dental surgeons, both at the beginning and at the end of one of several one-day courses on radiation protection. These courses were designed to cover the 'core of knowledge' required by the Ionising Radiation (Protection of Persons Undergoing Medical Examination or Treatment) Regulations 1988. The mean score at the start of each day was 22.86 (out of a maximum possible score of 80), while at the end it was 48.52. The results cast doubt on the belief of the General Dental Council that 'following qualification, dentists will have updated themselves in this area of dental practice'.

Education, Dental, Continuing↗
PubMed2004

Lauriston S. Taylor Lecture: The evolution of radiation protection--from erythema to genetic risks to risks of cancer to...?

Radiation Protection has evolved and will continue to evolve as new information becomes available, as the result of changes in public perception and concern and, perhaps in the future, as a result of enormous expenditures on reducing small risks. In the early part of the last century it was a sense of real danger among medical Practitioners that prompted the first set of exposure limiting suggestions. Addressing medical concerns continued to be the basis of guidance until after the Second World War. An array of new sources and applications led to new approaches, which modified many of the technical issues but didn't result in substantial changes in the dose limits. Fallout from the first generation of thermonuclear weapons in the 1950's resulted in focusing attention on genetic effects, which continued until the middle 1970's. Data from the Japanese Survivor Studies provided the information for risk based recommendations beginning in 1977 and continue to do so today. Both the ICRP and the NCRP are heavily criticized by both those groups of individuals which believe the risk estimates are underestimated and by those which believe the risks are greatly overestimated. Perhaps both organizations can take some comfort in Saint Thomas Aquinas' suggestion, "In medio virtus."

Age Factors↗
PubMedDate not supplied

History, current status, and trends of radiation protection standards.

Quantitative standards for protection against exposure to ionizing radiation were first formulated in the 1930s. Since that time, standards have been restated periodically in different radiation units and conceptual frameworks that reflect improved understanding of the biological effects of radiation interactions and their consequences for human health. In the 1970s the expression of protection standards shifted from a dose- to a risk-based approach, with dose limits established to yield risks to radiation workers comparable with those for workers in other "safe" industries. Over the years, radiation protection standards have exhibited a downward trend to more rigorous limits that require increased commitments of personnel and resources for their enforcement. There are several reasons for this trend, including increased recognition of the long-term health effects of radiation, improved protection measures that permit radiation use at lower levels of exposure, growing numbers of persons exposed occupationally to radiation, and probably a greater intolerance to involuntary risks in society, with radiation targeted as a highly visible source of involuntary risks in the form of nuclear power plants and radioactive waste sites. In the past few years, reports of the Radiation Effects Research Foundation, United Nations Scientific Committee on the Effects of Atomic Radiation, and the National Research Council of the U.S. National Academy of Sciences have presented increased risk estimates for radiation exposure as a consequence of ongoing epidemiological analyses of human populations exposed to ionizing radiation. These risk estimates have enhanced public concern about radiation exposure and set the stage for discussions about the desirability of further reductions in exposure standards for radiation workers and members of the public. Such reductions would directly affect the professional activities, educational responsibilities, and administrative burdens of most medical and health physicists. These persons should understand the process of deriving risk estimates from epidemiological data, the factors that influence the risk estimates, how risk estimates are integrated into radiation protection standards, and the possible impact of more rigorous standards on the use of radiation in medicine.

Biophysics↗
PubMed2006

[Radiation protection. Implications for clinical practice on the new regulations governing roentgen ray irradiation and radioprotection].

In 2001 or 2002, the legislator made substantial alterations to the "Röntgenverordnung" [regulations governing use of roentgen ray radiation] and "Strahlenschutzverordnung" [regulations governing radiation protection]. This was done to bring German law in line with EU Directives 96/29/Euratom (basic safety standards for the protection of the health of workers and the general public against the dangers arising from ionizing radiation) and 97/43/Euratom (health protection of individuals against the dangers of ionizing radiation in relation to medical exposure). Proper use of radiation in medicine requires that those involved in its application are aware of the biological effect of radiation. When staff and others are protected good organization and appropriate technology at the workplace can achieve a great deal. In the new directives, the radiation protection for the patient is quantified and the responsibility of the physician is clearly pointed out. The most important aim is uniform quality throughout Europe in radiological diagnosis and radiation protection.

Clinical Medicine↗