Bone Scan: What to Expect and Why It Matters

A bone scan is a medical imaging test used to help doctors check for problems in your bones. It can show areas of unusual bone activity that may be caused by injury, infection, arthritis, fractures, cancer, or other conditions. If your doctor has recommended a bone scan, you may be wondering what it is, how it works, and whether it is painful or safe.

This article explains what a bone scan is, why it is done, what happens during the test, and how to prepare. It also answers common questions so you know what to expect.

What Is a Bone Scan?

A bone scan is a type of nuclear medicine imaging test. It uses a small amount of radioactive material, called a tracer, to look at how your bones are functioning. The tracer is injected into a vein, usually in your arm, and it travels through your bloodstream to your bones.

Areas of bone that are repairing, inflamed, injured, or affected by disease may absorb more tracer than normal. A special camera then takes pictures of your skeleton, highlighting these areas.

Unlike an X-ray, which mainly shows bone structure, a bone scan shows bone activity. That makes it useful for finding problems that may not appear clearly on regular imaging. For a broader overview of related symptoms, you may also find bone pain causes and relief options helpful.

Because bones are constantly remodeling, changes in activity can appear before visible damage becomes obvious on other scans. That is one reason doctors may choose this test when symptoms are ongoing but the cause is still unclear.

Why Is a Bone Scan Done?

Doctors order bone scans for several reasons. The test can help detect:

• Bone fractures, especially stress fractures
• Bone infections, also called osteomyelitis
• Arthritis or joint inflammation
• Bone tumors
• Cancer that has spread to the bones
• Unexplained bone pain
• Problems with blood flow to bone
• Joint replacement complications
• Bone disease related to other medical conditions

A bone scan is often used when other tests do not provide enough information. It may also help doctors find the source of pain or monitor how a known condition is changing over time.

For example, if a doctor suspects spreading disease, an imaging review may include a related article such as the National Cancer Institute’s overview of bone metastases to understand how cancer can affect the skeleton.

It can also be useful after an injury when pain lasts longer than expected, especially if a stress fracture or small hidden break is suspected. In those cases, the scan may show activity before a fracture line is visible on an X-ray.

What Does a Bone Scan Show?

A bone scan can show “hot spots” and, sometimes, “cold spots.”

• Hot spots are areas where more tracer is absorbed. These can suggest increased bone activity, which may happen with fractures, infection, arthritis, or cancer.
• Cold spots are areas with less tracer uptake. These may sometimes indicate reduced blood flow or certain types of bone damage.

A bone scan does not always give a specific diagnosis by itself. Instead, it helps doctors identify suspicious areas that may need more testing.

In some cases, findings may overlap with conditions that affect bone structure or healing, including bone erosion and other inflammatory changes.

That is why the report is usually interpreted together with your symptoms, your medical history, and any other imaging you have already had. A single abnormal area may mean something very different in someone with recent surgery than it would in someone with a history of cancer.

How to Prepare for a Bone Scan

Preparation for a bone scan is usually simple. In many cases, you can eat, drink, and take your regular medications unless your doctor tells you otherwise.

Before the scan, you may be asked to:

• Drink extra water to help flush the tracer from your body
• Remove jewelry or metal objects
• Wear comfortable clothing or change into a hospital gown
• Let the medical team know if you are pregnant, breastfeeding, or think you might be pregnant
• Tell your doctor about any recent imaging tests, especially those involving contrast material

You should also tell the medical team if you have had a recent surgery, injury, or injection site problem, since these can affect the scan results.

If you have trouble standing, lying flat, or staying still for long periods, mention that before your appointment. The imaging team can often make small adjustments to help you stay comfortable during the test.

It is also a good idea to arrive a little early so you have time to review instructions, complete paperwork, and ask questions about the process.

What Happens During the Test?

A bone scan usually takes place in two main steps.

1. The tracer injection

A technician injects the radioactive tracer into a vein. You may feel a small pinch, similar to a blood draw. After the injection, you usually wait a few hours before the pictures are taken. This waiting period gives the tracer time to circulate and collect in your bones.

2. The imaging scan

When it is time for the scan, you will lie on a table while a camera slowly moves over your body. The camera does not touch you. It detects the tracer and creates images of your bones.

You may be asked to stay very still so the pictures are clear. The scan itself is painless, though lying still for a while may feel uncomfortable for some people.

In some cases, the scan covers your whole body. In others, the imaging may focus on one area, such as the spine, hip, knee, or a specific painful spot.

Some centers may take additional views after the first set of images if the radiologist needs a closer look at one area. This does not necessarily mean something serious is wrong; it may simply help improve the quality of the final interpretation.

How Long Does a Bone Scan Take?

The full process can take several hours because of the waiting time after the injection. The actual imaging portion usually takes between 30 minutes and an hour, depending on what part of the body is being scanned.

Your appointment may be longer if additional images are needed.

Because of the waiting period, many people bring a book, music, or something else quiet to help pass the time. The staff may also suggest moving around a little between the injection and the scan unless they ask you to rest for a specific reason.

Is a Bone Scan Safe?

Bone scans are generally considered safe. The tracer used is given in a very small amount and leaves the body over time, mostly through urine.

The amount of radiation is low, but because the test does use radioactive material, it is not usually done during pregnancy unless the benefits clearly outweigh the risks.

If you are breastfeeding, your doctor may give specific instructions about whether to pause temporarily after the scan.

For most adults, the benefit of getting clear diagnostic information outweighs the small radiation exposure. Your doctor will only recommend the test when it is likely to help answer an important medical question.

Are There Any Side Effects?

Most people do not have side effects from a bone scan. Rarely, some people may notice:

• Mild pain or bruising at the injection site
• A slight allergic reaction
• Discomfort from lying still during the scan

Serious reactions are uncommon. If you feel unwell after the tracer injection, tell the medical staff right away.

After the test, drinking fluids and urinating often may help remove the tracer from your body more quickly. If your team gives you special instructions, follow those first.

What Happens After a Bone Scan?

After the scan, you can usually return to your normal activities. Drinking plenty of water may help remove the tracer from your body more quickly. Your doctor may also recommend flushing with fluids for the rest of the day.

The test results are reviewed by a radiologist or nuclear medicine specialist, who sends a report to your doctor. Your doctor will explain what the findings mean and whether you need more tests, treatment, or follow-up.

If your scan is being used to evaluate a specific diagnosis, your doctor may combine the findings with other studies such as a bone mineral density test to build a more complete picture of your bone health.

Sometimes the report may mention that the findings are “nonspecific.” That means the scan shows an area of concern, but it does not clearly identify the cause. In that situation, your doctor may use another imaging test, blood work, or a follow-up scan to get more information.

How to Understand Bone Scan Results

Bone Scan results are often described as normal or abnormal.

• A normal scan means there are no unusual areas of tracer uptake.
• An abnormal scan shows one or more areas of increased or decreased tracer activity.

An abnormal result does not always mean cancer or a serious condition. For example, arthritis, a healing fracture, or recent surgery can also cause changes on a bone scan.

That is why bone scan results are usually interpreted alongside your symptoms, physical exam, and other imaging tests.

If your doctor points out a hot spot, ask what it might mean in the context of your health history. The location of the finding matters a great deal, as does whether it matches where you are feeling pain.

Bone Scan vs. X-Ray, CT, and MRI

It helps to understand how a bone scan compares with other imaging tests.

• X-ray: Good for showing bone structure and fractures, but may miss early changes.
• CT scan: Gives detailed cross-sectional images and is useful for complex bone issues.
• MRI: Best for soft tissue, bone marrow, and some hidden injuries.
• Bone Scan: Best for detecting bone activity and finding areas affected by disease throughout the body.

Each test has a different purpose. Your doctor chooses the one that best fits your symptoms and medical history.

For example, MRI may be preferred when the concern involves ligaments, cartilage, or bone marrow changes, while a bone scan may be more useful when the question is whether one or more bones are actively changing somewhere in the body. In some situations, doctors use more than one test to get a clearer answer.

Conditions a Bone Scan May Help Evaluate

A bone scan may be recommended for several common medical concerns. These can include longstanding joint pain, a recent sports injury, unexplained swelling, or symptoms that suggest a problem deeper in the bone.

Stress fractures and small breaks

Stress fractures can be difficult to spot early. A scan may show increased bone activity before the fracture becomes obvious on an X-ray. This can be especially helpful for athletes, runners, and people who have changed their activity level suddenly.

Bone infection

When bone infection is suspected, the scan may help show where the infection is active. Doctors may use it with blood tests, a physical exam, and other imaging studies.

Arthritis and inflammation

Inflammation in or around a joint can change how bone tissue behaves. A scan may help show which joints are involved and whether the activity is widespread or limited to one area.

Cancer that affects the bones

Doctors often use bone scans to check whether cancer has spread to the skeleton or to help evaluate unexplained bone pain in someone with a cancer history. The scan does not diagnose cancer on its own, but it can identify areas that need closer attention.

Other causes of abnormal bone activity

Hardware from prior surgery, healing after a fracture, and some chronic bone conditions can all influence scan results. That is why a clear explanation of your recent medical history is so important before the test.

What Questions Should You Ask Before the Test?

If you are scheduled for a bone scan, you may want to ask your doctor or imaging team:

• Why is this test being recommended?
• What will the scan help us learn?
• Do I need to stop any medications before the appointment?
• Should I drink extra water before or after the test?
• How will the results be shared with me?
• Will I need any follow-up imaging?

Asking these questions can make the appointment feel less stressful and help you understand the role the test plays in your care.

Common Questions About Bone Scans

Does a bone scan hurt?

The scan itself does not hurt. You may feel a brief pinch when the tracer is injected, but the imaging is painless.

Will I be radioactive after the test?

You receive a small amount of radioactive tracer, but it leaves your body naturally over time. It does not make you dangerous to be around. Your doctor may still advise drinking fluids and urinating often after the scan.

Can I go back to work after a bone scan?

In most cases, yes. Most people can return to normal activities right after the test.

How accurate is a bone scan?

Bone scans are very useful, but they are not always specific. They can detect abnormal bone activity, but they may not always tell exactly what is causing it. That is why doctors sometimes order additional tests.

Why would a doctor order a bone scan after another imaging test?

A bone scan can find bone problems that are not obvious on X-rays or CT scans. It is especially helpful when symptoms do not match earlier test results.

Can a bone scan show healing?

Yes. Healing bone often shows increased activity, which is why a follow-up scan can sometimes help doctors see whether an injury or fracture is improving over time.

When Should You Talk to Your Doctor?

Contact your doctor if you have:

• Ongoing bone pain
• Swelling near a bone or joint
• A fracture that is not healing
• A history of cancer with new bone symptoms
• Fever with bone pain
• Questions about whether the test is safe for pregnancy or breastfeeding

Your doctor can explain why the scan is being recommended and how it fits into your overall care.

If your pain is severe, getting worse, or limiting your ability to move normally, do not wait for the scan alone to provide answers. Ongoing symptoms may need prompt medical review.

The Bottom Line

A bone scan is a helpful imaging test that shows how active your bones are. It is often used to look for fractures, infection, arthritis, cancer, and other conditions that affect bone health. The test is generally safe, painless, and straightforward, though it may take several hours from start to finish.

Understanding what to expect can make the process less stressful. If your doctor recommends a bone scan, it is usually because the test can provide important information that other imaging methods may miss.

For people trying to understand unexplained bone symptoms, a bone scan can be an important part of the diagnostic process and a useful step toward the right treatment plan.