Different Methods of Bone Density Test
A bone density test determines the composition of bone using a technique called DXA or densitometry. The test is most commonly advised among elder women, who have greater chances of osteoporosis.
Earlier this test was recommended only after sudden fracture in bones due fall down or a small injury. Bone densitometry is the most common test performed to detect abnormality in bone. A bone density test uses X-rays to measure how many grams of calcium and other bone minerals are packed into a segment of bone. The test is performed in radiology departments or clinics. The test is painless and involves minimal exposure to X- ray.
There are many types of test conducted for bone density- Dual energy X-ray absorptiometry (DXA or DEXA); Quantitative computed tomography (QCT), Qualitative ultrasound (QUS), Dual photon absorptiometry (DPA), Single energy X-ray absorptiometry (SEXA) are some of the test practiced by radiologist.
Bone density test is performed on physical basis where bone likely gets break if density is very less than normal. The bones include the lower spine regional lumbar vertebrae, narrow neck of the femur bone adjoining the hip and the bones of the forearm and wrist.
Contents of the bone that is mineral, calcium are measures using x-ray test. If the content is found above normal or normal level the test considered as negative. With the help of the density test doctor, measures the risk of osteoporosis. Normal X-ray shows 40% bone loss while DXA show 2% bone loss. The strong bones permit few X- rays beam to pass through them. The measurement of the amount of X-ray beams blocked by the bone and soft tissues is performed. Results are reported in scores of T and Z which are compared with the normal one to determine the exact density of bone.