Bone Density Scan

A bone density scan is a painless test that uses a very small dose of radiation to produce images of the spine and hips to measure bone loss and assess a person's risk for developing fractures. A bone density scan can help your doctor diagnose osteoporosis or determine whether your osteoporosis treatment is working. Early detection using bone density measurement is the best way to protect yourself from the potentially debilitating effects of osteoporosis.

A bone density measurement will determine your bone mineral density (BMD) for the area measured. This information will help your doctor determine if you need to take certain steps to protect your bone health.

You will be exposed to very little radiation — in most cases, less than a standard chest X-ray. As with any medical procedure, be sure to tell your doctor if you are pregnant.

Preparing for the scan

Bone density scans require very little special preparation. Ask your doctor about any medications you take. Leave your jewelry at home and wear loose, comfortable clothing to the test.

During the scan

St. Mary's Women's Imaging Center uses an advanced bone density diagnostic device called dual energy X-ray absorptiometry (DEXA). A DEXA study takes about 30 minutes. The test is performed while you lie or sit on a table. The scanner will move back and forth over the part of your body being examined. You should remain as still as possible during the test. The technologist may adjust your body or the scanner during the exam.

Scan results

Bone density scan results are measured in two scores: T-score and Z-score.

The T-score shows the amount of bone you have compared with an average, healthy 30-year-old adult. A score of -1 and above is considered normal. A score between -1.1 and -2.4 is classified as low bone mass. A score of -2.5 and below is defined as osteoporosis.

The Z-score compares the amount of bone you have compared with other people your age and gender. An usually high or low score may indicate an issue and may require additional testing.