Imre Balásházy

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The apparent discrepancy between the reported preferential occurrence of bronchial carcinomas in central bronchial airways and current dose estimates for inhaled particles suggests that experimentally observed local accumulations of particles within bronchial airway bifurcations may play a crucial role in lung cancer induction. Here, we computed(More)
PURPOSE In this study a biophysical mechanism-based microdosimetric model was applied to predict the biological effects of inhaled radon progenies in homes and in uranium mines. MATERIALS AND METHODS The radon daughter concentrations of more than 2000 homes were averaged in case of home exposure and the New Mexico uranium mine data were used in case of(More)
One way of studying the risk to human health of low-level radiation exposure is to make biological experiments on living cell cultures. Two 210Po alpha-particle emitting devices, with 0.5 and 100 MBq activity, were designed and constructed to perform such experiments irradiating monolayers of cells. Estimates of dose rate at the cell surface were obtained(More)
Aerosol deposition studies with tracheobronchial casts and models have demonstrated that inhaled particles are preferentially deposited within transitional bifurcation zones, exhibiting hot spots in the vicinity of carinal ridges. The goal of the present study is to quantify the inhomogeneity of theoretically predicted deposition patterns by local(More)
Cellular hit probabilities of alpha particles emitted by inhaled radon progenies in sensitive bronchial epithelial cell nuclei were simulated at low exposure levels to obtain useful data for the rejection or support of the linear-non-threshold (LNT) hypothesis. In this study, local distributions of deposited inhaled radon progenies in airway bifurcation(More)
The observable responses of living systems to ionizing radiation depend on the level of biological organization studied. Understanding the relationships between the responses characteristic of the different levels of organization is of crucial importance. The main objective of the present study is to investigate how some cellular effects of radiation(More)
The primary objective of this study was to quantify the local inspiratory and expiratory aerosol deposition in a highly asymmetric five-generation tracheobronchial tree. User-enhanced commercial codes and self-developed software was used to compute the air velocity field as well as particle deposition distributions for a large size range of inhalable(More)
Particle transport and deposition within a model alveolus, represented by a rhythmically expanding and contracting hemisphere, was modeled by a three-dimensional analytical model for the time-dependent air velocity field as a superposition of uniform and radial flow components, satisfying both the mass and momentum conservation equations. Trajectories of(More)
In the case of radon exposure, the spatial distribution of deposited radioactive particles is highly inhomogeneous in the central airways. The object of this research is to investigate the consequences of this heterogeneity regarding cellular burdens in the bronchial epithelium and to study the possible biological effects at tissue level. Applying(More)
Health effects related to the deposition of inhaled aerosol particles in the respiratory system strongly depend on the local deposition patterns. These patterns are highly sensitive to the shape of the airway geometry. The current study presents an exact mathematical description of a morphologically realistic airway bifurcation by further developing an(More)