LUNG DOSIMETRY FOR INHALED RADON PROGENY IN SMOKERS

Cigarette smoking may, change the morphological and physiological parameters of file lung. Thus file primary objective of the present study was to investigate to what extent these smoke-induced changes can modify, deposition, clearance and resulting doses of inhaled radon progeny, relative to healthy non-smokers (NSs). Doses to sensitive bronchial target cells were computed for four categories of smokers: (1) Light, short-term (LST) smokers, (2) light, long-term (LLT) smokers, (3) heavy, short-term (HST) smokers and (4) heavy, long-term (HLT) smokers. Because of only small changes of morphological and physiological parameters, doses for the LST smokers hardly differed from those for NSs. For LLT and HST smokers, even a protective effect could be observed, caused by. a thicker mucus layer and increased mucus velocities. Only, in the case of HLT smokers were doses higher by about a factor of 2 than those for NSs, caused primarily by impaired mucociliary clearance, higher breathing frequency, reduced lung volume and airway, obstructions. These higher doses suggest that the contribution or inhaled radon progeny to the risk of lung cancer in smokers, May be higher than currently, assumed on the basis of NS doses.