microdosimetric model
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Exposure to radon and radon decay products in some residential areas and at workplaces constitutes one of the greatest risks from natural sources of ionising radiation. Recently, increasing attention has been paid to the precise estimations of this health risk by numerous models. The compartmental model published in ICRP Publication 66 (HRTM) has been used for calculating alpha activity concentration in human lung. Energy deposition in the tissue was calculated by the Bethe-Bloch equation. The aim of this study was to check the performance and to compare the reliability of the microdosimetric models. In this work different thicknesses of mucus in the cases of non-smokers and smokers has been considered. Transformed cells were considered as the radiation risk parameters. The radiation risk evaluation for different exposure levels was based on homogeneous and heterogeneous distributions of target cells. The results of application of these procedures were compared with the epidemiological study of Czechoslovakian uranium miners.
- MeSH
- biologické modely * MeSH
- dávka záření MeSH
- hodnocení rizik metody MeSH
- hornictví statistika a číselné údaje MeSH
- kouření epidemiologie MeSH
- látky znečišťující životní prostředí škodlivé účinky MeSH
- lidé MeSH
- lineární přenos energie MeSH
- nádory plic epidemiologie etiologie MeSH
- nádory vyvolané zářením epidemiologie etiologie MeSH
- plíce metabolismus účinky záření MeSH
- počítačová simulace MeSH
- radiační ochrana metody MeSH
- radiometrie * MeSH
- radon analýza farmakokinetika toxicita MeSH
- relativní biologická účinnost MeSH
- reprodukovatelnost výsledků MeSH
- senzitivita a specificita MeSH
- vztah dávky záření a odpovědi MeSH
- znečištění vzduchu ve vnitřním prostředí škodlivé účinky MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- srovnávací studie MeSH
- validační studie MeSH
- Geografické názvy
- Česká republika MeSH
PURPOSE: The aim of this paper is to investigate the limits of LET monitoring of therapeutic carbon ion beams with miniaturized microdosimetric detectors. METHODS: Four different miniaturized microdosimeters have been used at the 62 MeV/u 12C beam of INFN Southern National Laboratory (LNS) of Catania for this purpose, i.e. a mini-TEPC and a GEM-microdosimeter, both filled with propane gas, and a silicon and a diamond microdosimeter. The y-D (dose-mean lineal energy) values, measured at different depths in a PMMA phantom, have been compared withLET¯D (dose-mean LET) values in water, calculated at the same water-equivalent depth with a Monte Carlo simulation setup based on the GEANT4 toolkit. RESULTS: In these first measurements, no detector was found to be significantly better than the others as a LET monitor. The y-D relative standard deviation has been assessed to be 13% for all the detectors. On average, the ratio between y-D and LET¯D values is 0.9 ± 0.3, spanning from 0.73 ± 0.08 (in the proximal edge and Bragg peak region) to 1.1 ± 0.3 at the distal edge. CONCLUSIONS: All the four microdosimeters are able to monitor the dose-mean LET with the 11% precision up to the distal edge. In the distal edge region, the ratio of y-D to LET¯D changes. Such variability is possibly due to a dependence of the detector response on depth, since the particle mean-path length inside the detectors can vary, especially in the distal edge region.
- MeSH
- celková dávka radioterapie MeSH
- design vybavení MeSH
- fantomy radiodiagnostické MeSH
- izotopy uhlíku terapeutické užití MeSH
- kalibrace MeSH
- metoda Monte Carlo MeSH
- miniaturizace MeSH
- počítačová simulace MeSH
- polymethylmethakrylát MeSH
- radiometrie přístrojové vybavení MeSH
- radioterapie těžkými ionty přístrojové vybavení MeSH
- voda MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
The topic of the article is to define the average value of linear energy transfer (LET) for carcinogenic effects of radon progeny. The microdosimetric model of boundary specific energy is used. It follows that the effect at high LET should decrease approximately with the third power of LET. This is verified by the analysis of the relationship between radiation effects ratio and LET in published experiments with oncogenic transformation of mammalian cells irradiated with the monoenergetic alpha particles. If these cells are exposed with the radon irradiator, our analysis leads us to conclude that the oncogenic effect of radon progeny is comparable to that of alpha particles with a LET of 75 keV/μm. It is about a quarter lower than the LET value, where the effect of the monoenergetic alpha particles reaches its maximum level. Some implications for lung cancer due to radon inhalation may also be carefully examined.
- MeSH
- alfa částice * MeSH
- dceřiné produkty radonu škodlivé účinky MeSH
- karcinogeneze * MeSH
- křeček rodu Mesocricetus MeSH
- lidé MeSH
- lineární přenos energie * MeSH
- myši inbrední C3H MeSH
- myši MeSH
- nádorová transformace buněk účinky záření MeSH
- nádory plic MeSH
- nádory vyvolané zářením MeSH
- onkogeny MeSH
- radon škodlivé účinky MeSH
- relativní biologická účinnost * MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
