Empirical instruments based on ionisation recombination that have been used for radiation protection measurements are reviewed, and relations are derived from recombination theory that show that the response of such detectors can be readily predicted. This effect can be used as a basis for instruments that respond to different types of ionising radiation approximately in the way required by the quality factor-linear energy transfer relation recommended by the ICRP for use in radiation protection. Intitial recombination of ionisation in a gas depends on the ionisation density and hence on the linear energy transfer along the tracks of charged particles. The use of detectors based on ionisation recombination in radiation protection This would benefit the environment by directing scarce resources to more urgent environmental problems. Whilst empirical research to test the ICRP hypothesis should continue, until there is clear evidence against it, this simple and cost-effective approach should be retained. In view of the relatively insignificant effect of regulated releases of ionising radiation on the environment, the economic cost of further regulation will not result in a significant environmental benefit. In this paper I will challenge this view, arguing firstly that this statement is almost always quoted out of its proper context, and secondly that the ICRP hypothesis does adequately protect the environment from the effects of ionising radiations. In particular, the often quoted International Commission on Radiation Protection (ICRP) hypothesis that: If humans are protected from the effects of ionising radiation, then flora and fauna are also adequately protected has been criticised as being too anthropocentric and not adequate for protection of the environment. There has been a recent trend in the radioecological and radiation protection community towards greater regulation of the effects of ionising radiations on biota. The objective of this paper is to present the (rarely heard) argument in favour of retention of the present system of radiation protection of the environment. The case against protecting the environment from ionising radiation On the other hand, while ionising radiation is known to cause immunosuppression, large doses target the bone marrow and haemopoiesis lethally and In contrast, immunoprotective UVA irradiation protects the cutaneous cytokine array, inhibits IL-10 upregulation and increases IFN-gamma and IL-12 expression. It is also associated with cutaneous cytokine derangements, such that Th-2 cytokines (IL-4, IL-10) are increased at the expense of Th-1 cytokines (IFN-gamma, IL-12), and with histamine and inflammatory prostaglandin activity. Thus the UV-immunosuppressed state is promoted by oxidative damage and depletion of endogenous antioxidant molecules. The UVA immunoprotective effect is strongly dependent on the induction of a cutaneous redox-regulated enzyme, haem oxygenase (heat shock protein 32) that is known to protect cells from oxidative stress, and it is consistent that a number of exogenous antioxidants (vitamin E, vitamin C, green tea polyphenols, isoflavones) can protect effectively from photoimmuno-suppression. Increasingly larger UVA exposures increasingly immunosuppress mice.
Controversy rages over the immunosuppressive potential of the UVA waveband, 320-400 nm, but we demonstrate that environmentally relevant doses of UVA not only are immunologically innocuous, but provide protection against UVB-immunosuppression. Photoimmunological studies in mice during the past 20-30 years have established the action spectrum for UV-induced immunosuppression, implicating the UVB waveband, 290-320 nm.
As a consequence, the mechanisms underlying UV-induced immunosuppression have been more readily characterised, whereas surprisingly little is known about immunosuppression resulting from ionising radiation. In direct contrast, ionising radiation penetrates much more efficiently, and has a multitude of internal targets throughout the body. Solar UV radiation, the ubiqitous environmental non-ionising radiation, initiates its immunomodulating effects almost entirely in the skin.
Immunosuppression by non-ionising and ionising radiation - are there similarities? A more intensive study by the ILO on the protection of workers against non-ionising radiation was proposed for 1980-81. Several ILO publication on safety standards and codes of practice for protection against mainly ionising radiation in various occupational situations are indicated. International Nuclear Information System (INIS)Ī chronological account since 1934 of the activities of the International Labour Organization (ILO) in the protection of workers against risks due to ionising and non-ionising radiations is given. The work of the ILO in the field of protection of workers against ionising and non-ionising radiations
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