A bone scan is a test to help find the cause of your back pain. A bone scan can often find a problem days to months earlier than a regular X-ray test.
Two very different kinds of tests may be called bone scans. One type tests the density of the bone and is used to diagnose osteoporosis. This type of bone scan uses narrow X-ray beams or ultrasound to see how solid the bone is. No preparation is required for this test, which takes only a few minutes and has no side effects. (See Dual-Photon Absorptiometry and Peripheral Bone Density Testing.)
The second type of bone scan is used to identify areas where there is unusually active bone formation. It is frequently used to pinpoint stress fracture sites or the presence of arthritis, infection, or cancer. A radioactive substance is injected into a vein in your arm. This substance, called a tracer, travels through your bloodstream and into your bones. This could take several hours.
A special camera takes pictures of the tracer in your bones. Areas that absorb little or no amount of tracer appear as dark or “cold” spots. Areas of fast bone growth or repair absorb more tracers and show up as bright or “hot” spots in the pictures. Hot spots may point to problems such as arthritis, a tumor, a fracture, or an infection.
No fasting or other preparation is required. The amount of radioactivity absorbed during a technetium bone scan is minimal, and there are usually no side effects. You may feel some discomfort as the IV line is placed. Some people may feel nauseous. Tell your physician if you are or may be pregnant or are a nursing mother before you schedule this test.