Tomography is a method of sectional imaging of the internal structures of a body. The method is based on the analysis of radiation absorption in tissues in different directions, followed by computer reconstruction of the full image. X-ray tomography is the first tomographic technique based on X-ray radiation. X-rays are absorbed to different extents by tissues of different density which facilitates the visualisation of internal organs. To enhance image contrast, the so-called contrast media are administered to patients. One of the applications of nanotechnology in CT is the development of new contrast agents based on nanomaterials.