The Image Processing Toolbox Image Data provides a 3D volumetric chest scan that can be used in Image Processing Apps and in conjunction with a 3D image processing example within Image Processing Toolbox: https://www.mathworks.com/help/images/segment-lungs-from-3-d-chest-mri-data.html

Opening the .mlpkginstall file from your operating system or from within MATLAB will initiate the installation process available for the release you have. This .mlpkginstall file is functional for R2017a and beyond.
Watch this video to learn more about how to explore this data inside MATLAB: https://www.mathworks.com/videos/3d-volumetric-image-processing-demo--1487886076699.html