What is the difference between a CAT scan and an MRI scan?
A CAT scan is very similar to an x-ray as it still uses x-rays. However, The x-rays are ‘collated’ (that is they are focused through a very small section of the body (think of looking through a tube)). One exposure takes the volume x-rayed and allocates it value that corresponds basically to the attenuation (amount of x-ray energy absorbed) by the skin, fat, tissue, bone, tissue, fat, skin sequence the x-ray travels through. The CAT machine then moves the tube sideways and takes another shot. The tube is also rotated and further exposures taken (Actually there are banks of ‘tubes’). Advanced computation is then used to work out the density of each small volume, which can be mapped visually to represent the type of tissue and an internal picture of the body generated. MRI uses magnetic fields to align the atoms in the body, a radio frequency pulse (that causes hydrogen atoms to resonate) is targeted at the area of interest. This causes the Hydrogen atoms to spin at a particular frequenc
