CT brain scans. Assortment of coloured computed tomography (CT) scans of the human brain, seen on a light box. At left is the head sectioned in sagittal view; all other scans show the brain in horizontal (axial) section. A rounded brain tumour is revealed (magenta) in some of the brain scans at upper and lower left. CT scanning creates slice" images through the body using X-rays. It is useful in detecting brain tumours and cancer."