[en] Czech studies of uranium miners in the Jachymov region cover the 1970-1995 period and include nearly 900 cases of lung cancer which developed within 40 years. The role of the Czech cohort studies is demonstrated in the light of current knowledge of the effects of radiation and regulation principles in radiological protection

No abstract available

[en] Cesium radio-isotopes, especially cesium-137 (¹³⁷Cs) are among the radionuclides of main importance produced by a fission reaction in reactor or a nuclear weapon explosion. In the environment, ¹³⁷Cs is a major contaminant which can cause severe β, γirradiations and contaminations. ¹³⁷Cs is distributed widely and relatively uniformly throughout the body with the highest concentration in skeletal muscles. A treatment becomes difficult afterwards. The purposes of this report are Firstly to compare the Prussian blue verses cobalt and potassium ferrocyanide (D.I. blue) efficiency for the ¹³⁷Cs decorporation and secondly to assess a chronological treatment with D.I. blue. (author)

[en] The labeling of anti-tumor monoclonal antibodies (McAB) with radionuclides has been regarded as our main aim in the past 12 years. A procedure of preparation of ultrapure carrier-free ¹¹¹In has been developed. Anti-tumor McABs labeled with ¹¹¹In via a bifunctional conjugating agent (DTPA cycloanhydride) were used successfully in clinical trials. ^99mTc-labeled McAB fragments prepared by a direct method were also proved very powerful in diagnosis of gastric carcinoma. The methodological problems of both direct and indirect labeling have been also our major concerns. We were involved in study of the coordination chemistry of technetium and rhenium. Using the PKU AMS facility, we studied the binding of nicotine and its derivative NNK to DNA. The detection sensitivity is 1 adduct per 10¹⁰ DNA. The results show that the nicotine itself has little genetic toxicity, but its derivative NKK is much more genetically toxic

[en] An overview is provided of several recent advances in the understanding of the molecular events that occur when cells are exposed to ionizing radiation. A basic knowledge of molecular radiobiology is necessary so that the radiation oncologist can (i) screen cancer patients for an abnormally reduced or exaggerated response to radiotherapy; and (ii) devise novel ways to counter the molecular pathways that sustain malignant progression. 84 refs., 3 tabs., 1 fig

[en] The purpose of this article is to assess the influence of biological and aerosol parameters on human lung dose with regard to a comparison with the corresponding recommended dose values of the International Commission on Radiological Protection (ICRP). The dose conversion factor which gives the relationship between effective dose and potential alpha energy concentration of inhaled short-lived radon decay products (²¹⁸Po, ²¹⁴Pb, ²¹⁴Bi/²¹⁴Po) is calculated with a dosimetric approach. The calculations are based on a lung dose model with a structure that is related to the recently recommended ICRP respiratory tract model. Because of the short half-lives of the investigated nuclides, simplifying modification of the model were possible. Firstly, the underlying assumptions of the model are described. Secondly, important input parameters of the model are varied to assess the uncertainty of the dose conversion factor due to uncertainty of these parameters. The main emphasis is focused on biological and aerosol parameter variability like variation of breathing rate and breathing mode, clearance rates, critical cells for the induction of lung cancer, particle size and dispersion of the activity size distributions. The possible range of dose conversion factors is discussed both for indoor and mine aerosol conditions in the framework of the presented dose model. The investigation shows that the dosimetric approach leads to a dose conversion convention which is a factor of more than two times higher than the recommended epidemiological values of the ICRP of 3.9 mSv.WLM^-1 for the public and 5.1 mSv.WLM^-1 at working places. The dosimetric results yield both for indoor and mine aerosol conditions dose conversion factors in the range of 10 mSv.WLM^-1 to 15 mSv.WLM^-1 depending on breathing mode. (author)

[en] The results of the examination of the local population of Siberia exposed to radiation at different years and their children and grandchildren are given (over 14000 persons). The cells of the people, exposed to radiation and their children and grandchildren are more sensitive to mutagenic action of radiation, chemical mutagens and viruses. It is shown that simultaneous application of pentoxylum and complex of vitamins A, E and C reduced 4-5 times the number of cells with cytogenic breaks in the radioactively exposed patients. A cytogenic method and investigation of tooth enamel by a method of ESR, as well as a micronuclei test were applied for definition of radioactive doses received by the population

[en] Inhalation is the main route of intake of radioactive material for workers, and can be an important pathway for members of the public following accidental releases of radioactivity to the environment. Much of the inhaled radioactivity initially deposits in the nose, typically over 40% for particles of aerodynamic diameter (d_ae) greater than 2 μm. However, there is remarkably little information on the clearance from the human nose of particles deposited during inhalation and, until now, none on the clearance of the significant fraction of material that remains in the nasal passage for more than 12 hours. NRPB is conducting a volunteer study to determine the effects of particle size and breathing pattern on particle deposition in, and clearance from, the human nasal passage. This article summarises results obtained to date. (author)

[en] One of the unique aspects of PET is its ability to noninvasively quantify metabolic processes. Metabolic rate parameters are estimated by fitting the time-activity curves from regions of interest (ROIs) placed on dynamic PET images with a kinetic model. In many cases it is possible to couple these datasets with common parameters, such as the time delay between arrival of tracer in the ROIs and the sampling site. Data from eight ROIs placed about images of the myocardium were coupled by the parameters describing the metabolite concentration in the blood. The method was evaluated by comparing estimates of k₂ made using the coupled region method and the standard process of fitting data from each region separately. In addition, comparisons were made between estimates of k₂ and measured myocardial oxygen consumption. Very little change in mean values of k₂ was obtained. The variances, however, were reduced by an average of 37%, compared to the standard method, when the common parameters were not constrained. When the values of the common metabolite parameters were constrained to values previously measured, the average variance in estimates of k₂ was reduced by 30%. The authors have demonstrated that the use of this technique can significantly increase the precision of estimates of myocardial oxygen consumption utilizing ¹¹C-acetate PET images. More precise estimates of such quantities can facilitate detection of small regional and/or temporal physiological changes measured with PET. Furthermore, this method can be utilized whenever it is known a priori that one or more kinetic model parameters has the same value for every set of ROI data. 35 refs., 3 figs., 1 tab

[en] Using a mathematical methodology based upon the theory of pattern recognition, the adequacy of this methodology being confirmed by the corroborative results obtained with neuro-net non-parametric methods of analysis, it proved possible to discriminate reliably between generalized organism's statuses, as described with a big number of laboratory indices, of the inhabitants of different areas of a bid industrial city which differ in levels of radioactive and non-radioactive environmental pollution. 13 refs