X-rays have been in use for many decades. Also known as radiography, this is the most commonly used imaging procedure in veterinary practices. The x-ray images are produced using the same processes used in human medicine except that the equipment is sized for use with dogs, cats, and other small animals. Portable equipment may be used in a large animal clinic that treats horses and other large animals. Although the procedure is painless, in some cases pets are sedated or have a general anaesthetic to reduce the stress associated with the procedure, to position the animal correctly and to help the animal remain still while the images are taken.