Osteoporosis, a disease that lowers bone density and causes brittle bones, affects over 24 million Americans. Annually, this disease is responsible for over 1.3 million fractures, of which 250,000 are hip fractures. Increased awareness of osteoporosis has led to more advanced methods of diagnosing and monitoring the disease. To assist in diagnosing low bone density, physicians may choose to prescribe an examination called a bone densitometry or bone density scan. This examination estimates the amount of bone mineral content in specific areas of the body, including the spine, hip, and forearm, or the total body. Your physician will use the bone density information to decide if treatment is necessary. Whether a treatment is prescribed or not, you may need a follow up study at a later date to evaluate your progress.
You may want to take a short quiz to determine whether you should discuss osteoporosis with your doctor. The following questions about bone densitometry are frequently asked by patients like yourself.
What causes osteoporosis?
Bone is living tissue that is constantly being broken down and reformed. As a person grows, bone forms faster than it breaks down until it reaches a peak bone mass between the ages of 25 and 35. After age 35, both men and women lose bone at a greater rate than it forms, causing bone loss. Women after menopause start to lose bone at a much more rapid rate than men of the same age. This rapid bone loss is usually due to a decrease in the production of the estrogen hormone. As a greater amount of bone is lost, the bones become porous and brittle. Early detection is the best way to protect against osteoporosis.
How is the bone density scan done?
You will be asked to lie perfectly still on the scan table and you will be able to breathe normally throughout the procedure. A scanner arm will pass over the area of interest, for example, your lower spine or hip. A dual energy beam of x-ray passes through your body and is measured by a detector arm. This technology is called Dual-energy X-ray Absorptiometry or DXA. DXA works by measuring the amount of x-rays that are absorbed by the bones in your body. The two x-ray energies allow the machine to tell the difference between bone and soft tissue, giving a very accurate estimate of bone density.
- Avoid calcium supplements for two hours prior to your appointment.
- Avoid wearing clothing with metal and you may not have to change your clothes
- If you are, or think you are, pregnant, you need to inform the technologist before the exam. In this case, your physician will determine if the x-ray is medically necessary for the diagnosis.
If you have any additional questions or concerns please contact your physician.