Measurement of Thoron in the Breath

Abstract
Measurements of thoron in the breath of about 200 patients injected with colloidal thorium dioxide (about one-half had been injected with unknown volumes) were made by counting four liters of exhaled breath in a radon-in-breath monitor. The average radiation dose-rates to the lungs were estimated as 0.3 rem per week but the dose-rates to the bronchus and trachea are 10 to 15 times as great.