1. A segmentation method for determining pleura boundaries of a lung, comprising: acquiring image data from an imaging device; generating a set of two-dimensional (2D) slice images based on the acquired image data; determining, by a processor, a seed voxel in a first slice image from the set of 2D slice images; applying, by the processor, a region growing process to the first slice image from the set of 2D slice images starting with the seed voxel using a threshold value; generating, by the processor, a set of binarized 2D slice images based on the region grown from the seed voxel; filtering out, by the processor, connected components of the lung in each slice image of the set of binarized 2D slice images; and identifying, by the processor, the pleural boundaries of the lung based on the set of binarized 2D slice images.