High-resolution wide-field synchrotron radiation micro-CT for large human lung specimen imaging

We have been developing a large-field and high-resolution micro-CT system that is highly specialized for visualization of the entire secondary pulmonary lobule in a large human lung specimen using a consumer-grade 36M-pixel single lens reflex camera. The secondary pulmonary lobule, a fundamental unit of lung structure, reproduces the lung in miniature. The lung specimen was set in an acrylic cylindrical case with 36 mm diameter and 40 mm height. A field of view of the micro-CT is 40.6 mm wide x 15.1 mm high with pixel size of 3.07 mu m using offset CT scanning for enlargement of the field of view. In all, 7200 projections were acquired over an angular range of 360 deg with an angular step of 0.05 deg. Then, we constructed a 13,220 x 13,220 x 4912 voxel image with an isotropic voxel size of 3.07 mu m for three-dimensional visualization of the entire secondary lobule. The whole specimen is depicted in the image using large field of view imaging and micro-architectures of alveolar shapes visualized in the identical image.