AP chest x-rays are harder to read than PA x-rays and are therefore generally reserved for situations where it is difficult for the patient to get an ordinary chest x-ray, such as when the patient is bedridden. In this situation, mobile X-ray equipment is used to obtain a lying down chest x-ray (known as a supine film).
An MRI system requires helium to keep its magnet cool, especially when imaging a patient, and continues to consume helium to remain cool when the magnet is idling. An MRI system must be cooled to 4.2 K, or -452Â° F, and liquid helium is the most effective way to sufficiently cool the magnet to that temperature.
Cryosurgery (also called cryotherapy) is the use of extreme cold produced by liquid nitrogen (or argon gas) to destroy abnormal tissue. Cryosurgery is used to treat external tumors, such as those on the skin. For external tumors, liquid nitrogen is applied directly to the cancer cells with a cotton swab or spraying device.