A study of radiographic determination of the total lung capacity

Determination of the total lung capacity(TLC) has been widely used in the evaluation of the pulmonary functionand in its application to clinical medicine. A roentgenographic method for the determination of the total lungcapacity of Korean children of all ages has not yet been documented in the literature. This method requiresposterioanterior and lateral views of the chest, and consists principally of the summation of a series ofelliptical cylindroids into which the lungs are divided. The measurement and calculation of the total lungcapacity by the roentgenographic method were carried out on 320 randomly selected normal Korean children, 180males and 120 females. The following results were obtained. 1. The value of TLC in male was larger than that infemale in the same age height and weight group, the mean difference between male and female being 606 ml. The meanvalue of TLC in female was 77% of that in male. 2. TLC tended to increase as height increased, the correlationcoefficients(r) being 0.86 with standard deviation of +161 ml in male and +562 ml in female, and it had anapproximation to the value of 1Ht3 inmale and 0.8Ht3 in female. 3. The TLD tended to increase slightly as weightincreased, the correlation coefficient(r) being 0.78 with standard diviation of +1061ml in male and +738 ml infemale. 4. Measurement of roentgenogram as regards TLC determination is relatively simple, rapid and accurate.