The layer thickness of CT thin layer scan is 5mm, but it can also be made thinner, up to 3mm or even 1mm, by using reconstructed layer thickness technology or 3D reconstruction technology, which can reduce some of the volume effects and improve spatial resolution, so thin layer CT is mostly used to observe relatively small lesions, or relatively small tissues and organs, commonly used for thin layer scanning of small lung nodules. Thin-layer scans can also be performed on special areas, such as the pituitary gland, orbit, inner ear, and adrenal glands.