What Is a Bone Scan?

What to expect when undergoing this test

Doctor reading the x-ray in the office
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A bone scan, also known as bone scintigraphy, is a nuclear imaging technique in which a small amount of radioactive material is injected into your vein to highlight areas of bone damage or disease. The injected compound, called a tracer, is taken up in cells and tissues that are undergoing repair. A bone scan is a relatively safe procedure and is useful for diagnosing a number of bone conditions, including fractures, infections, and cancer.

Purpose of Test

A bone scan may be ordered if you are experiencing unexplained bone pain or have signs and symptoms of a bone disease. Among some of the reasons why your doctor would request a bone scan:

  • To assess bone trauma that an X-ray cannot pick up
  • To pinpoint fractures that are difficult to locate
  • To investigate an unexplained bone fracture (pathologic fracture)
  • To determine the age of a fracture
  • To investigate persistent pain in the extremities, ribs, or spine
  • To assess a bone infection detected by other tests
  • To assess damage caused by arthritis and other bone disorders
  • To determine whether blood flow to a bone has been obstructed
  • To establish where a bone cancer originated
  • To stage bone cancer
  • To monitor your response to treatment for a bone disease

Usefulness in Diagnosis

By using a bone scan, a nuclear medicine technologist can quickly pinpoint areas of damage on a specialized instrument called a gamma camera. The gamma camera is designed to capture patterns of internal radiation and translate them into a two-dimensional image. It is the same technology used for a positronic emission tomography (PET) scan.

A bone scan is an extremely sensitive test that can detect even minor abnormalities in bone metabolism. It is central to the investigation of bone cancers, including secondary (metastatic) cancers.

Among the conditions a bone scan can help diagnose, monitor, or characterize:

A bone scan is performed routinely following certain cancer diagnoses to proactively check for bone metastasis.

Advantages and Disadvantages

A bone scan has both its advantages and disadvantages. Among them:

  • A bone scan will produce images that are far less detailed than a positron-emission tomography (PET) scan, but will also be far less costly. 
  • While a bone scan is highly sensitive in spotting lesions and other bone abnormalities, the images are non-specific and may require further investigation with PET, computed tomography (CT), magnetic resonance imaging (MRI), or a bone biopsy.
  • A bone scan can sometimes miss smaller tumors and is less specific in detecting metastatic bone tumors. A study published in the journal Radiology concluded that a bone scan had an 80.3 percent accuracy in detecting a secondary bone malignancy compared to a PET scan, which had an accuracy of 94.1 percent.

With that being said, because a bone scan is less expensive than any of these other tests, it may provide a valuable entry point to an investigation. 

Risks and Contraindications

A bone scan involves the use of a radioactive tracer, most commonly a substance known as technetium-99m, which is injected into your bloodstream.

While this may cause concern, the level of emitted radiation is extremely low, far less than what you would be exposed to with a CT scan. It also has a relatively short drug half-life (around six hours), meaning that it will be excreted from your system within one to two days.

The gamma scanner itself does not emit radiation. The only side effects associated with the procedure (besides the discomfort of having to lay still for a long period of time) are those related to the radioactive tracer.

Injection Side Effects

The six most common side effects associated with technetium-99m (occurring in more than 1 percent of patients) are:

  • Soreness or swelling at the injection site
  • Changes in taste
  • Chest pain or discomfort
  • Rapid heart rate
  • Changes in smell
  • Irregular heart rate

Other less likely side effects include blurred vision, dizziness, fatigue, itching, lightheadedness when rising (postural hypotension), nausea, vomiting, and weakness. According to prescribing information from the U.S. Food and Drug Administration, allergic reactions to technetium-99m is extremely rare.

Contraindications and Considerations

You should advise your doctor if you have a heart condition or are taking any heart medications. This doesn't preclude you from having the test, but it does mean that your condition should be monitored during the procedure.

Generally speaking, nuclear medicine of any sort is avoided in pregnant women. Obesity may also be a factor insofar as most scanning tables have a maximum weight capacity of 220 pounds. If you are heavier, your doctor may need to explore other diagnostic options.

Women who breastfeed can get a bone scan but will be asked not to nurse for a day or two following the test, as there may be traces of technetium-99m in breastmilk.

Before the Test

A bone scan does not require much preparation on your part. Once the appointment is scheduled, your doctor will walk you through the procedure and advise you as to what to do to achieve the best results.

Timing

A bone scan is a time-consuming process. After the radioactive tracer is delivered by intravenous (IV) injection, you have to wait two to four hours to ensure that the chemical has fully circulated in your body. During the waiting period, you can either stay in the hospital or leave and come back.

The scan itself can take anywhere from 30 minutes to an hour. If your doctor orders a three-phase bone scan (used to identify fractures not seen in other imaging studies), you will undergo an initial scan during the IV infusion, a second after the infusion, and a third three to four hours later.

Depending on the logistics, you may need to set aside the entire day. If you decide to leave during the waiting period, be sure to return no later than 30 minutes before your scheduled scan.  

Location

The bone scan will be performed in the nuclear medicine unit of a hospital or at a specialized testing facility. The room itself (called the scanning room) is outfitted with a specialized scanning table and two parallel gamma cameras, each of which is roughly the size of an extra-large ice chest.

What to Wear

You need to undress for the procedure. While the office will have space to store your clothing, wallet, and cell phone, it is best to leave any jewelry or unneeded valuables at home.

Food and Drink

You do not need to fast before a bone scan. You can eat your regular diet but may want to avoid drinking too much as you will need to drink four to six glasses of water just before the scan is performed.

If you take medications containing bismuth, such as Peptol-Bismol or Kaopectate, stop taking them at least four days before the test, as they can interfere with the imaging. Your doctor may be able to prescribe an alternative if needed.

Cost and Health Insurance

The cost of a bone scan can run anywhere from $400 to $700, depending on the provider and where the test is done. To this end, it is important to know the total costs in advance, including how much your health insurance will cover and what your co-pay and out-of-pocket expenses will be, if you're enrolled. The test will invariably require insurance pre-authorization, which your doctor’s office can submit on your behalf.

If you are denied coverage for any reason, ask your insurer for a written reason for the denial. You can then take the letter to your state insurance consumer protection office and ask for help. Your doctor should also intervene and provide additional motivation as to why the test is essential.

If you are uninsured, speak with the lab to see if there are monthly payment options.

What to Bring

In addition to your identification and health insurance cards, you may want to bring something to entertain yourself if you plan to stay during the waiting period. If you plan to be on your computer or cell phone a lot, be sure to bring a power cord or charger, and perhaps even headphones or a headset.

If your child is having the bone scan, bring toys, snacks, a blanket, pacifier, or whatever else you need to keep the child occupied. You can check in advance to see if there is an on-site nursery or playroom you can use during the wait.

Other Considerations

After the bone scan is completed, you should be able to drive yourself home. In the unlikely event you have blurred vision, an irregular heartbeat, or any other side effect, speak with the medical staff. They can advise you when it is safe to leave or whether someone should pick you up.

During the Test

On the day of the test, after signing in and confirming any insurance information, you may be asked to sign a liability form stating that you are aware of the purpose and risks of the procedure.

Prior to the bone scan, a nurse or technologist will review your medical history, including your pregnancy status and any drugs you may be taking. 

Pre-Test

Before the actual scan can be done, the radioactive tracer must be injected. This is done in a sterile IV room as follows:

  • Once you are positioned on the examining table, a nurse or technologist inserts a flexible IV catheter into a vein in your arm or hand. You may experience fleeting, minor pain as the needle is inserted.
  • The tracer is then injected into the IV, during which you may feel a cold sensation moving up your arm, but likely no pain. From start to finish, the infusion process takes around 10 to 15 minutes.
  • You're then free to move around while the tracer circulates in the bloodstream and begins to be absorbed in bone. During this waiting period, you will need to drink four to six glasses of water to flush any excess tracer not absorbed by cells. You can eat and do anything else you’d like during this time.

If you plan to leave, let the nurse or technologist know. He or she will be able to tell you when you need to return. Check in with reception when you do.

Throughout the Testing

The bone scan is performed approximately three hours after the injection. When it's time, you are led to a changing room to remove all your clothing, jewelry, eyewear, and removable dental appliances. After changing into a hospital gown, you will be asked to urinate one last time to remove as much of the remaining tracer from your body as possible.

Upon entering the scanning room, you are positioned on the scanning table by the technologist. Thereafter, you need to remain absolutely still as a series of scans are taken from head to foot.

Using a remote control, the technologist moves the cameras—positioned above and below the table—up and down your body in tandem while viewing the images on a video monitor. Your position will occasionally be altered to obtain a clearer picture.

A bone scan is not noisy like an MRI and is less likely to trigger claustrophobia, since you won’t be placed in an enclosed space (as you would with an MRI or CT scan).

The technologist will remain in the room the entire time. If you feel any discomfort from lying too long, let the technician know, particularly if you have pre-existing bone or joint pain.

If your child is undergoing the scan, you may need to stay in the room to keep her still and calm. Some imaging units will have TVs with children’s programming to keep the child distracted.

Post-Test

Once your scan is complete, you may be asked to wait until the technologist conducts a final review of the images. If more images are needed, you may be asked to return. Don’t let this worry you. More often than not, it is simply because the image resolution wasn’t sharp enough or the positioning of the camera needed adjustment. It doesn’t mean that the technologist found something worrisome.

Once the technologist tells you that the scanned images are acceptable, you can change back into your regular clothes and leave. Double check to ensure you have all of your belongings.

After the Test

You will want to care when rising from the scanning table since you will have been lying on your back for a long time. It is best to prop yourself on your elbows, wait a moment, push yourself into a seated position, and wait another moment before hopping off the table. This is especially true if you have low blood pressure or existing back, leg, or hip pain. The technetium-99m injection can also sometimes cause a drop in blood pressure, which can leave you lightheaded.

Once home, call your doctor if you experience any unusual symptoms or side effects, including irregular heartbeat, chest pains, fever, chills, or vomiting.

Despite having been injected with a radioactive substance, you will not be harmful to anyone who touches, kisses, or stands close to you. Sexual intercourse is also safe.

Interpreting the Results

A day or two after the test, your doctor will review the results with you. The nuclear medicine imaging report will include copies of the scans as well as a detailed description of the findings.

The aim of the study is to identify areas of abnormal bone metabolism. The image itself, which depicts your entire skeleton, may contain darker "hot spots" where the tracer molecules have accumulated. This is indicative of an abnormality which, depending on its size and location, may give your doctor a clue as to what is going in. By contrast, lighter "cold spots" may be suggestive of reduced blood flow or certain types of cancer.

While a bone scan can pinpoint an abnormality, the image itself is not diagnostic (meaning that is cannot tell us what the problem is). Clinical expertise, supported with additional lab and imaging tests, may be needed to make a definitive diagnosis.

Follow-Up

Follow-up testing may be ordered if an abnormality is found. Depending on the suspected cause, you may need to undergo blood tests, a bone biopsy, or more sophisticated forms of imaging such as a single-photon emission computerized tomography (SPECT) scan used to look deep inside the bone.

A Word From Verywell

A bone scan is a valuable tool for diagnosis, both in terms of its cost and sensitivity. While the test has limitations and is invariably time-consuming, complications are rare and you can usually go back home or to work without any lingering side effects.

If your bone scan shows hot spots, try not to assume the worst. Remember that, for all of its virtues, a bone scan can only tell if something is abnormal; it cannot tell you what that abnormality is.

On the other hand, if a scan is clear but you still have symptoms, tell your doctor and see what other testing options are available. If your doctor is unable to help, seek a second opinion and ask that your records be forwarded to the specialist in advance of your appointment.

You can also request a copy of the report for yourself which can usually be delivered a digital format. 

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