What happens at very low levels of radiation exposure? Are the low dose exposures beneficial?
| dc.contributor.author | Dalcı, Deniz | |
| dc.contributor.department | TAEK-ÇNAEM | tr_TR |
| dc.date.accessioned | 2019-02-13T08:54:54Z | |
| dc.date.available | 2019-02-13T08:54:54Z | |
| dc.date.issued | 2006 | |
| dc.description.abstract | Radiation is naturally present in our environment and has been since the birth of this planet. The human population is constantly exposed to low levels of natural background radiation, primarily from environmental sources, and to higher levels from occupational sources, medical therapy, and other human-mediated events. Radiation is one of the best-investigated hazardous agents. The biological effects of ionizing radiation for radiation protection considerations are grouped into two categories: The deterministic and the stochastic ones. Deterministic radiaton effects can be clinically diagnosed in the exposed individual and occur when above a certain “threshold” an appropriately high dose is absorbed in the tissues and organs to cause the death of a large number of cells and consequently to impair tissue or organ functions early after exposure. A clinically observable biological effect (Acute Radiation Sendromes, ARS) that occurs days to months after an acute radiation dose. Stochastic radiation effects are the chronic effects of radiation result from relatively low exposure levels delivered over long periods of time. These are sort of effects that might result from occupational exposure, or to the background exposure levels. Such late effects might be the development of malignant (cancerous) disease and of the hereditary consequences. These effects may be observed many years after the radiation exposure. There is a latent period between the initial radiation exposure and the development of the biological effect. For this reason, a stochastic effect is called a Linear or Zero-Threshold Dose-Response Effect Exposure to very low levels of radiation is a controversial issue, originating many debates throughout the scientific community. What happens at very low levels of radiation exposure? There is a stochastic correlation between the number of cases of cancers or genetic defects developed inside a population and the dose received by the population at relatively large levels of radiation. Although there is no scientific evidence to prove, attempts have been made to extrapolate the data from these levels of dose to low levels of dose (close to the levels received from background radiation). Studies of populations living in high natural-background areas have not reported detrimental health effects attributable to radiation. The research has also demonstrated that the types and numbers of gene activated by low doses of radiation are different than those activated by high radiation doses. These changes in gene activation seem to be able to modify the response of cells to subsequent radiation exposure, termed the "adaptive response". This adaptive response seems to be the manifestation of a protective effect that may reduce risk at very low doses. Current knowledge in molecular biology shows no evidence of a threshold effect for Stochastic Effects. Therefore, any level of radiation may be considered to cause them. Conversely, some studies show that low levels of irradiation are in fact beneficial to the health (Radiation Hormesis). However, in the absence of clear scientific evidence, the regulators adopted a conservative approach and consider all levels of radiation as being potentially damaging to the human body (LNT theory). According to LNT theory; the effects of low doses of ionizing radiation can be estimated by linear extrapolation from effects observed by linear extrapolation from effects observed by high doses. There is not any safe dose because even very low doses of ionizing radiation produce some biological effect. The results of many investigations do not support the LNT theory. Furthermore relationship between environmental radon concentrations and lung cancer even contradict this theory and clearly suggest a hormetic effect -radiation hormesis-. Although data are still incomplete, extensive epidemiological studies have indicated that radiation hormesis is really exist. In this rewiev, contradictory evidence Lineer No-Threshold Theory and Radiation Hormesis Effect is discussed. | tr_TR |
| dc.identifier.citation | Dalcı, D. (2006). What happens at very low levels of radiation exposure? Are the low dose exposures beneficial?. The Fourth Eurasian Conference on Nuclear Science and Its Application : Presentations, (s. 344-349). 31 October-3 November 2006. Baku, Azerbaijan. | tr_TR |
| dc.identifier.endpage | 349 | tr_TR |
| dc.identifier.startpage | 344 | tr_TR |
| dc.identifier.uri | http://kurumsalarsiv.tenmak.gov.tr/handle/20.500.12878/1085 | |
| dc.language.iso | eng | tr_TR |
| dc.publisher | Azerbaijan National Academy of Sciences Institute of Radiation Problems ve Turkish Atomic Energy Authority | tr_TR |
| dc.relation.journal | The Fourth Eurasian Conference on Nuclear Science and Its Application : Presentations, 31 October-3 November 2006. Baku, Azerbaijan. | tr_TR |
| dc.rights | info:eu-repo/semantics/openAccess | tr_TR |
| dc.subject | Radiation exposure | tr_TR |
| dc.subject | Radyasyona maruz kalma | tr_TR |
| dc.subject | Low dose exposures | tr_TR |
| dc.subject | Düşük doz maruziyeti | tr_TR |
| dc.subject | Beneficial | tr_TR |
| dc.subject | Yararlı | tr_TR |
| dc.subject | Adaptive response | tr_TR |
| dc.subject | Adaptif tepki | tr_TR |
| dc.subject | Radiation hormesis | tr_TR |
| dc.subject | Radyasyon hormesisi | tr_TR |
| dc.subject | LNT | tr_TR |
| dc.title | What happens at very low levels of radiation exposure? Are the low dose exposures beneficial? | tr_TR |
| dc.type | conferenceObject | tr_TR |