[Comparison of the helium rebreathing method and the x-ray film densitometry in epidemiological screening tests of CNSLD (author's transl)].

Two methods for the examination of the residual volume were compared under the special conditions of epidemiological studies. The X-ray Photo Densitometry RV/TLC is measured as a quotient of the brightness of the lung radiographs during inspiration and expiration maximums. The Helium Rebreathing method is a gas mixture technique. The correlation between both methods proved to be significant (r = 0,60). The advantages and disadvantages of these methods for epidemiological studies were discussed.