Assessment of the dose from radon and its decay products in the Bozkov dolomite cave.

The dose from radon and its progeny remains a frequently discussed problem. ICRP 65 provides a commonly used methodology to calculate the dose from radon. Our work focuses on a cave environment and on assessing the doses in public open caves.

Application of the advanced radon diagnosis methods in the indoor building environment.

The health risk and dose calculations from exposure to indoor radon and its decay products are generally based on long-term integral measurements and standard ICRP recommendations. In this context, the results of assessments predicate more about human activities inside the building instead of a quality and an effectiveness of applied measures against the radon. The present paper is focused on a set of different measuring techniques and methods practically used for a classification of buildings regarding to the radon protection requirements.

Lung cancer in French and Czech uranium miners: Radon-associated risk at low exposure rates and modifying effects of time since exposure and age at exposure.

Radon is recognized as a public health concern for indoor exposure. Precise quantification derived from occupational exposure in miners is still needed for estimating the risk and the factors that modify the dependence on cumulated exposure. The present paper reports on relationship between radon exposure and lung cancer risk in French and Czech cohorts of uranium miners (n = 10,100).

Dissolution behaviour of 238U, 234U and 230Th deposited on filters from personal dosemeters.

Kinetics of dissolution of (238)U, (234)U and (230)Th dust deposited on filters from personal alpha dosemeters was studied by means of a 26-d in vitro dissolution test with a serum ultrafiltrate simulant. Dosemeters had been used by miners at the uranium mine 'Dolní Rozínka' at Rozná, Czech Republic. The sampling flow-rate as declared by the producer is 4 l h(-1) and the sampling period is typically 1 month.

Evaluation of committed effective doses from internal contamination of 241Am using experimentally determined parameters of the contaminant.

Internal contamination of workers with 241Am has occurred a few times since the beginning of the 1970s, mainly in the workplace where radionuclide sources were produced, and later on, also during liquidation of radioactive waste. Contamination in workers was measured in vivo and bioassay was performed. Solubility of aerosol in lungs was studied by in vitro dissolution test with a simulant solution of the extracellular airway lining fluids.

Development and application of anthropomorphic voxel phantom of the head for in vivo measurement.

The in vivo measurement of the activity deposited in the skeleton is a very useful source of information on human internal contaminations with transuranic elements, e.g. americium 241, especially for long time periods after intake.

The quality of dental radiography in the Czech Republic--results of a TLD and film postal audit.

Since 2002, the postal audit in dental radiography has been supplementing standard quality control (QC) tools for dental intraoral X-ray machines. An aim of the audit is to check basic X-ray machine parameters (field size, exposure reproducibility), and a quality of the whole process of diagnostic imaging (entrance surface air-kerma measurement, a check of film processing and an image quality evaluation). The standard QC tests, performed by private companies, check mainly the X-ray unit.

Almost twenty years' search of transuranium isotopes in effluents discharged to air from nuclear power plants with VVER reactors.

Airborne effluents of 5 stacks (stacks 1-5) of three nuclear power plants, with 9 pressurized water reactors VVER of 4,520 MWe total power, were searched for transuranium isotopes in different time periods. The search started in 1985. The subject of this work is a presentation of discharge data for the period of 1998-2003 and a final evaluation.

Decrease of total activity with time at long distances from a nuclear accident or explosion.

Two data groups were analyzed: (1) the exposure rate in the former Czechoslovakia after the Chernobyl accident in 1986, and (2) the decrease of beta activity of an atmospheric fallout sample taken in Bratislava during 24 h on 30 May 1965. Both quantities decreased with the first power of time. This pattern of decrease is explained by applying the same mathematical formalism as is also used to describe the decrease in postnatal mortality with age.

The decline of postnatal mortality from gastrointestinal anomalies with age.

It has been previously shown that mortality from congenital anomalies decreases with the first power of age with the exception of "gastrointestinal anomalies". On the other hand, mortality declines with the second power of age in the category "certain conditions originating in the perinatal period". According to the theory of congenital individual risks, the dying out of more impaired individuals causes these two types of mortality decline.

Lung cancer risk among Czech tin and uranium miners--comparison of lifetime detriment.

First epidemiological evidence of lung cancer risk from exposure to radon was based on studies of uranium miners. The risk in other mines was reported later. The cohort study among 2466 Czech tin miners was conducted in order to estimate the size of the risk and to compare it to that in uranium mines.

238Pu, 239,240Pu, 241Am, 90Sr and 137Cs in soils around nuclear research centre Rez, near Prague.

Forty-four soil samples were taken around the nuclear research centre Rez, near Prague. The mean activity concentrations of 238Pu, 239,240Pu, 241Am, 90Sr and 137Cs in uncultivated soil were 0.010, 0.

The weekly measurement deviations of indoor radon concentration from the annual arithmetic mean.

The difference between weekly measurements and the annual arithmetic mean of radon indoor concentration CRn,Indoor was studied in the Czech Republic. The deviations were analysed for 1537 weekly measurements which were consecutively obtained in 29 rooms over a period of 1 year and the annual arithmetic mean was calculated for each particular room. The relationship of the deviations to three meteorological parameters (i.

Assessment of occupational doses from internal contamination with 241Am.

A group of workers with occupational intakes of 241Am, which occurred a long time ago, has been followed for some time. Results of in vivo measurement and bioassay of excreta are compared with the values predicted by the ICRP Publication 78 model. The observed skeletal content is, as a rule, higher than the predicted one.

Analysis of mortality decline along with age and latent congenital defects.

Mortality from congenital anomalies is inversely proportional to age after the age of 1 year. The theory of congenital individual risk explains this mortality decline. The overall aim of this study is to test whether the theory describes mortality decline for all diseases within the first year of life and after the age of 1.

Czech miner studies of lung cancer risk from radon.

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of miners. Two such studies among Czech uranium miners were established in 1970 and 1980. A subcohort of 5002 miners and a nested-in case-control study contribute to a joint European project.

A case of repeated accidental inhalation contamination of a male subject with 137Cs.

Two consecutive incidents of internal contamination occurred within a 13-mo period when a male worker (56 y, 70 kg) briefly entered and stayed (during a breakdown of control apparatus for air contamination) in a radioisotope storeroom with air contaminated by an explosion of old ampules containing 137Cs solution. Monitoring of the first contamination began on day 34 and that of the second one within 1 h after inhalation. According to the two-exponential model, long-term biological half-times of 92 and 93 d were obtained for the first and second contaminations, respectively.

Theory of the age dependence of mortality from congenital defects.

A theory is presented, based on the evidence that the congenital defect of an individual is at one of many different levels. It is supposed that the individual mortality risk from congenital defect is lognormally or normally distributed in the population. The relationship between childhood mortality from seven congenital defects and age is described.

Study of lung cancer and residential radon in the Czech Republic.

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of men employed underground in mines where exposures are relatively high in comparison to indoor exposure. Risk from residential radon can be estimated from occupational studies. Nevertheless, as such extrapolations depend on a number of assumptions, direct estimation of the risk is needed.

Radon exposure and lung cancer risk--Czech cohort study on residential radon.

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of men employed underground in mines where exposures are relatively high in comparison to indoor exposure. Nevertheless, direct evidence of risk from residential radon is desirable. In 1990, a study was started comprising 12,000 inhabitants of an area with elevated radon concentrations.

Radon exposure and lung cancer risk: Czech cohort study.

Epidemiological evidence of lung cancer risk from radon is based mainly on studies of male miners. Recent results of one such study of Czech uranium miners who were restricted to lower exposure rates are reported. Two main factors that generally influence radiogenic risk of cancer, time since exposure and age at exposure, are analyzed.