ABSTRACT
X-ray computed tomography (CT) systems with high resolution (also known as micro-CT systems) have been developed over the last two decades and have been used with great success in small animal studies. A micro-CT scanner is based on the same underlying physical principle as a clinical CT scanner, but it is designed for higher-resolution imaging. It produces three-dimensional (3D) tomographic data at microscopic resolution (voxel size ≤100 μm3) by taking hundreds of 2D projections from multiple angles around the animal (Holdsworth and Thornton 2002). The X-ray source produces a cone beam, which is projected through the specimen with the resultant radiographic density of the specimen projected onto a 2D detector. The projections are used by a reconstruction algorithm that is generally based on the filtered back projection (Kak and Slaney 1988) (see Figure 36.1). The resultant micro-CT scan is a 3D matrix of voxels with values proportional to the mean linear attenuation coefficient of the material within each voxel; the 3D matrix can be sliced in any orientation to reveal different views of the anatomy.
