Dual Energy X-Ray Absorptionmetry (DEXA)
2 X-ray beams of different energy levels are targeted at the subject's bones. Some of the beam is absorbed by the bone and the rest passes through it. In essence, it is an X-ray and will also show the broken bones of the subject. It is the most accurate way of measuring the total amount of fat in a person.
Pros: Extremely Accurate, most accurate among the other methods
Cons: Very costly to operate and use with each use going up to a few thousand. (due to the nature of how it works)