Determining Average Linear Dimension and Volume of Korean Lungs for Lung Phantom Construction

The purpose of this study was to determine the average size and volume of lungs and to simulate the morphology of internal organs for the development of a Korean adult lung phantom. The body-size data of 2,195 males and 2,293 females aged between 20 and 60 y were included to calculate the average physical dimensions. Two hundred datasets of computed tomography corresponding to the average physique range were collected to measure the average linear dimensions (the length of x, y, and z-axis) of lungs. One set of lung CT images was finally obtained and converted to three-dimensional (3D) format. To confirm the validity of the new lung model, physical lung phantoms were constructed using International Commission on Radiation Units and Measurements (ICRU) density and similar density to what was obtained from the human CT image and then compared with the Lawrence Livermore National Laboratory (LLNL) phantom. The mean size of the chest width and thickness was 31.8 ± 2.8 and 21.4 ± 1.9 cm for males and 28.0 ± 1.6 cm and 19.4 ± 2.0 cm for females, respectively. The standard deviation of the lung dimension in this group was ± 3.0 cm in length, ± 0.8 cm in width, and ± 2.27 cm in depth. The two modified lung phantoms showed highly accurate geometry and linear attenuation coefficient vs. those of the LLNL phantom. The difference in CT number was ± 2% HU for the LLNL phantom and ± 4% HU for the human CT image based on a CT examination conducted using the chest CT protocol. Moreover, both lungs weighed 734 g to 1,246 g, within the range of the reference value of the ICRU report. These results demonstrate that a new lung model based on average linear dimension measurement in a group with average physique simulated the features and physical properties of real human lungs and facilitated further studies for phantom construction.