Measurement of total lung capacity by a roentgenography-planimetry method in children 4-16 years of age.

We have demonstrated the reliability of the planimetric method for the determination of total lung capacity (TCL) in children aged 4-16 in comparison with TLC measured by the plethysmography method. We have found power function formulas to be of greater potential usefulness than linear, logarithmic or exponential formulas for calculating TLC by the planimetric technique.