One of the key services which My Vital Metrics offers is the DEXA Scan. DEXA, (or sometimes just DXA), Dual-energy X-Ray Absorbiometry, is one of the gold standards in measuring body composition. In this article we will walk through the technology of DEXA by itself, and give you some sense of how it works, and why you might consider it.
DEXA – The Machine
DEXA was a machine originally developed to measure bone density, to diagnose conditions like osteoporosis, and within the NHS, and in health services all over the world, it is still the primary tool for doing this. However, DEXA machine also is great as measuring body composition. In this context it is used in medical setting to measure levels of muscle wastage (sarcopenia) owing to disease states or poor lifestyle. Using it on healthy people as part of body recomposition programmes has not been widespread in the UK, but is a recognised use and has been much more common to date in the US and Australia.
The machine divides up the body into three types of tissue. In body composition science, these are called compartments, so the DEXA is referred to as a 3 compartment model. The three compartments DEXA measures are Bone minerals, fat, and everything else that isn’t one of those two.
The ‘Dual-energy’ part of the name means that DEXA has two different X-Ray beams which pass through your body. A receiver on the other side will collect what is remaining of the X-Ray beam, measures it, and is able to make some calculations. One of the X-Rays is configured to pass right through soft tissue, but is absorbed by bone mineral. The greater the amount of bone mineral, the more of it is absorbed, and so you can get a calculation at that point through the body, how much bone mineral there is.