[Fundamental investigations for the deposition of aerosols from radioactive solutions in the upper and lower airways (author's transl)].

By means of 99mtechnetium diphosphonate and a scintillation camera we measured the deposition of aerosols. During normal breathing rhythm and without leading the aerosol by valves the retention in the lower airways was on an average of 5.6%, that is 0.07 ml/min. By installation of suitable valves for in- and expiration and mouth tubes, deep and complete expiration with breath holding the retention of the aerosol increases to 17.3-13.8% (0.22-0.17 ml/min); with normal breathing the deposition was only 9%. In the upper airways we found the following deposition rates: Nose/hypopharynx (inhalation via mask) 2.6%; Mouth and pharynx (after rinsing) 1.6%; Larynx 0.1%. A considerable part remains in the inhalation system; by special variations we were able to reduce this portion of the aerosol. After inhaling electro-aerosols (4 kv) the deposition in the lungs was 5.6%; the more the charge was reduced the more the deposition of the aerosol in the lung increased.