Dynamics of radon decay product activity in saliva following speleotherapeutic radon exposure

Radon decay product activity was measured in saliva of 10 male patients 20- 30 min after a 1-hour radon exposure in the gallery of the Gasteiner Heilst ollen (radon activity 36.2 kBq/m(3), radon progeny activity 20.3 kBq/m(3)), in 1 patient showing relatively high activity (75th percentile) measuremen ts were continued until 65 min after exposure. Patients were asked to colle ct about 2 mi of saliva in the mouth and produce it on a filter. After dryi ng the filter at 300 degrees C, radon progeny activity was measured. Activi ty (median) at 20-30 min after leaving the treatment area was 4.5 Bq (25th percentile 1 Bq; 75th percentile 21 Bq). In the patient who underwent addit ional measurements the activity showed a further increase up to 29 Bq (35 m in after radon exposure) before it continuously decreased to a very low act ivity (1-3 Bq) at 65 min after exposure. The results show that a significan tly increased radon decay product activity is found in saliva after speleot herapeutic radon exposure. Maximum values were observed 35 min after radon exposure. Radon decay product activity almost disappeared after about 1 h.