Measurements of Radon Progeny Size Distributions and unattached Fractions in the Thermal Gallery of Bad Gastein

Since 1953 the Thermal Gallery of Bad Gastein - an approximately 4500 m tunnel system near Böckstein - has been used for radon therapy. The factors presumed to be responsible for the observed therapeutic effects are: (i) the high radon concentration (approximately 166500 Bq/m³) in the air of the Thermal Gallery; (ii) the relatively high temperature (approximately 41°C); (iii) and the high relative humidity (approximately 70% - 95%). In the past, radon therapy has successfully been applied to the following diseases: rheumatic illnesses, Morbus Bechterew, chronic bronchitis, asthmatic diseases, and inhibited blood circulation. Despite the high bronchial doses incurred during the treatment, the total exposure time is too short to cause an increase in lung cancer risk.