Figure B.4

Concentration C/Co in the stomach wall as a function of time after intake. The radius of the stomach lumen is 3.908 cm, corresponding to a volume of 250 mL. The concentration in the lumen is considered to be uniform and is assumed to decrease exponentially with a half-time of 20 min. The depth of the mucous layer is 50 µm and that of the stem cell population is 200 µm.

For the conditions described here, the fraction of radon released to the blood stream due to diffusion through the stomach wall is 20%.

The absorbed dose to the cells at a depth, r, is related to the time-integrated radon concentration at this same depth. The integrated concentration, relative to that in the lumen is

For conditions described here, the time-integrated concentration at the location of the stem cells (depth = 200 µm) was approximately 30% of the integrated concentration in the lumen. As seen from figure B.3, the time-integrated concentration



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