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[On hygienic and ecological approaches in radiation protection].

In this paper the problem of substantiation of one of the basic radiation protection ensurance principle is considered: sufficiency of a man radiation safety ensuring for guaranteed ensuring of radiation safety of the environment living components. This paradigm formulated in ICRP recommendations and is often referred to as hygienic or anthropocentric approach to environment radiation protection is laid down the basis of all national, including Russian, regulations in the field of radiation safety. During the last 5-10 years a lot of papers have been published, in which the hygienic principle of environmental safety ensuring is considered as a matter of dispute and the certain logical basis and the quantitative comparative estimations of human exposure doses and most irradiated vulnerable parts of nature doses are given. Change of one of the main radiation protection paradigms will demand for resolution of the enormously difficult and labor-consuming scientific problems. In the present paper, on the basis of UNSCEAR models of critical population groups dose formation and consistent application of conservativeness principle it is shown that for the ground ecosystems today there is no strong reasons for refusal of a hygienic radiation protection principle for benefit of ecological one.

Ecology↗

Radiation protection by alpha-methyl-homocysteine thiolactone in vitro.

The radiation protective effect of thiol compounds is unequivocal and their use is only limited by their toxic effects. We used the principle of alpha alkylation, which renders amino acids unmetabolizable, to reduce the toxicity of homocysteine. This product, alpha-methyl-homocysteine thio-lactone, was tested for toxicity and radiation protective effect along with known protectors L-cysteine, cysteamine and WR 1065 in cell culture using V79-4 Chinese hamster lung cells. The three-day growth curve assays, useful to measure overall effects on cell growth, revealed lowest toxicity for alpha-methyl-homocysteine thiolactone (GL-2). Clonogenic survival tests, used to evaluate the retention of reproductive integrity, were carried out and revealed that GL-2 had no adverse effects in this test system. Radiation protection tests showed that GL-2 exhibited protective activity against radiation induced lethality above that seen with cysteine and cysteamine, but below WR 1065. However, GL-2 showed little or no negative effects toward the cell itself, in direct contrast to WR 1065. Our findings show a potentially important tool and principle to reduce toxicity of radiation protectors with analogous structures.

Animals↗

Radiation protection in space.

The challenge for planning radiation protection in space is to estimate the risk of events of low probability after low levels of irradiation. This work has revealed many gaps in our knowledge that require further study. Despite investigations of several irradiated populations, the atomic-bomb survivors remain the primary basis for estimating the risk of ionizing radiation. Compared with previous estimates, two new independent evaluations of available information indicate a significantly greater risk of stochastic effects of radiation (cancer and genetic effects) by about a factor of three for radiation workers, including space travelers. This paper presents a brief historical perspective of the international effort to assure radiation protection in space.

Astronauts↗

Ethical issues in radiation protection.

In this note the authors survey existing international radiation-protection recommendations of the ICRP, the IAEA, and the ILO. After outlining previous work on the ethics of radiation protection and risk assessment/management, the authors review ethical thinking on five key issues related to radiation protection and ethics. They formulate each of these five issues in terms of alternative ethical stances: (1) Equity vs. Efficiency, (2) Health vs. Economics, (3) Individual Rights vs. Societal Benefits, (4) Due Process vs. Necessary Sacrifice, and (5) Stakeholder Consent vs. Management Decisions.

Compensation and Redress↗

Pharmacologic effects of radiation protective compounds related to their protective effect in mice.

Effects of presumptive radiation protective substances on physiologic criteria such as oxygen consumption, rectal temperature, respiratory and acoustic response are described. The rate of oxygen consumption and rectal temperature cannot entirely be considered a reliable measure of radiation protection. Some substances cause a decrease in the investigated parameters, strong enough to incapacitate the treated individuals severely. This limits the use of such substances. It is suggested that not only the effect on the survival but also the metabolic effects on the organism caused by the substance have to be investigated.

Amphetamine↗

[The European Directive 96/29/Euratom through the history of radiation protection].

The new european directive concerning the radiation protection 96/29/Euratom is currently being transposed in national regulations. This directive is registered in a historical context. This context allows us to understand how it is realised and what philosophy underlies the actual structure and its possible shortcomings. Current developments of the radiobiology and the radio-epidemiology, notably important modifications of our knowledge about natural irradiation, the attention for genetic fragile populations and relationships between irradiation and cancer are likely to modify our perception of the radiation protection.

Europe↗

Radiation protection of human lymphocyte chromosomes in vitro by orientin and vicenin.

Orientin (Ot) and Vicenin (Vc), two water-soluble flavonoids isolated from the leaves of Indian holy basil Ocimum sanctum have shown significant protection against radiation lethality and chromosomal aberrations in vivo. In the present study the protective effect of Ot and Vc against radiation induced chromosome damage in cultured human peripheral lymphocytes was determined by micronucleus test. In order to select the most effective drug concentration, fresh whole blood was exposed to 4Gy of cobalt-60 gamma-radiation with or without a 30 min pre-treatment with 6.25, 12.5, 15.0, 17.5 or 20 microM of Ot/Vc. Micronucleus (MN) assay was done by cytochalasin induced cytokinesis block method. Radiation significantly increased the MN frequency (16 times normal). Pre-treatment with either Ot or Vc at all concentrations significantly (P<0.05-0.001) reduced the MN count in a concentration dependent manner, with the optimum effect at 17.5 microM. Therefore, fresh blood samples were incubated with/without 17.5 microM Ot/Vc for 30 min and then exposed to 0.5-4Gy of gamma-radiation. Radiation increased the MN frequency linearly (r(2)=0.99) with dose. Pre-treatment with Ot or Vc significantly (P<0.01-0.001) reduced the MN counts to 51-67% of RT alone values, giving DMFs of 2.62 (Ot) and 2.48 (Vc). Both the compounds showed significant antioxidant activity in vitro at the above concentrations, which was significantly higher than that of DMSO at equimolar concentrations. Thus, the results demonstrate that both the flavonoids give significant protection to the human lymphocytes against the clastogenic effect of radiation at low, non-toxic concentrations. The radioprotection seems to be associated with their antioxidant activity. The clinical potential of these protectors in cancer therapy needs to be investigated.

Adult↗

Special radiation protection aspects of medical accelerators.

Radiation protection aspects relevant to medical accelerators are discussed. An overview is first given of general safety requirements. Next, shielding and labyrinth design are discussed in some detail for the various types of accelerators, devoting more attention to hadron machines as they are far less conventional than electron linear accelerators. Some specific aspects related to patient protection are also addressed. Finally, induced radioactivity in accelerator components and shielding walls is briefly discussed. Three classes of machines are considered: (1) medical electron linacs for 'conventional' radiation therapy, (2) low energy cyclotrons for production of radionuclides mainly for medical diagnostics and (3) medium energy cyclotrons and synchrotrons for advanced radiation therapy with protons or light ion beams (hadron therapy).

Electrons↗

Accreditation in radiation protection for cardiologists and interventionalists.

Training in radiation protection is widely recognised as one of the basic components of optimisation programmes for medical exposures. Occupational and patient radiation risks in interventional radiology can be quite high and international bodies have shown concern on this item. Following recommendations of the International Commission on Radiological Protection and in accordance with the European Directive on medical exposures, some initiatives for training in radiation protection took place in Spain and Luxembourg. These provided practitioners of interventional radiology adequate theoretical and practical training in radiation protection. The main outcome of the pilot courses organised to this end is discussed, concluding its suitability to implement the European Directive in practice.

Accreditation↗

Setting standards for radiation protection: the process appraised.

Present radiation protection standards are based to a large extent on data that have been forced to conform with the linear non-threshold model. A review of the literature shows that there are examples of both data and theory that disagree with such a model. Established standard setting bodies seem not to have recognized this disagreement; indeed, as will be shown, there are many studies that they have neither cited, discussed, nor refuted. Additionally, examples of data adaptation and circular reasoning are to be found in the standard-setting process. Consequently, a new approach to the process is desirable. Numerous citations and quotations are given.

Dose-Response Relationship, Radiation↗

Guidelines for radiation protection in the cardiac catheterization laboratory.

Even though radiation levels in the catheterization laboratory are the highest encountered during any commonly performed diagnostic study, dose levels to laboratory personnel should not approach the maximum permissible. A certain minimum amount of radiation is necessary to produce optimal diagnostic images. Therefore, optimum use of radiation protection devices and measures is essential. The goal should be dose minimization, keeping personnel radiation dose as low as reasonably achievable. In the cardiac angiographic suite this goal can be assumed to have been accomplished if: (1) maximum use is made of suitable radiation protection devices, (2) film-and video-imaging chains are optimized, (3) good radiographic technique is employed, (4) strict ongoing quality control programs are maintained for radiographic equipment and cine processor, and (5) there is compliance with all federal, state and local regulations for the safe use of ionizing radiation.

Allied Health Personnel↗

[Shielding during dental X-ray examinations. Effectiveness of radiation protection measures for patients during X-ray examinations].

During dental X-ray examinations, lead rubber shields such as neck protections or half aprons are commonly used to protect the patient against unnecessary radiation. However, they are practically of no use to the patient as it has been shown by the present measurements. The scatter radiation produced in the body of the patient creates organ doses outside of the collimated radiation field. Other radiation protection measures are more effective and should be considered, although the doses are usually low.

Humans↗