Radon progeny activity in sweat following radon exposure in a warm and humid environment

The objective was to evaluate whether activity of radon progenies can be detected in sweat following speleotherapeutic radon exposure (40 kBq/m(3)) in a warm (38 degrees C) and humid (relative humidity >70%) environment. A group of 11 male patients with spondyloarthropathy (n=6) or non-inflammatory rheumatic diseases (n=5) underwent a 1-h treatment in the gallery of the Gasteiner Heilstollen, and 20 min after leaving the treatment area radon progeny activity was measured in sweat by utilizing a special filter set. The results suggest that radon is discharged with sweat, causing a significant activity of radon and radon progenies on the skin. This finding may be important from a clinical point of view, since specialists experienced in radon therapy have repeatedly emphasized the importance of the degree of radioactivity on the skin for the effectiveness of treatment. It has even been claimed that the skin is the major target for radon therapy, possibly because of the influence on Langerhans' cell function.