Scintigraphy is a type of diagnostic test that uses radiopharmaceuticals to produce enough gamma radiation to be captured by special cameras. It’s a procedure with several complex steps – let’s break each component down a little further!
Radiopharmaceuticals are medications that contain radioisotopes – for this purpose, radioisotopes are simply substances that emit gamma rays. When the drug enters the patient's body, it will travel to a specific tissue or organ, where it emits the gamma radiation that will be picked up by cameras outside the body. These cameras produce images that are similar to those produced by X-rays. However, scintigraphy images are more detailed than X-rays, and can help doctors find abnormalities inside the bone. This type of nuclear bone scan can reveal fractures or other problems that could be overlooked during an X-ray.
A bone scan test is a nuclear scan (meaning one that uses radioactive substances) that looks for abnormalities in your bones. It is most often ordered to find the cause of skeletal pain after other scans (like CT scans, skeleton X-rays, or PET scans) failed to provide answers. Usually, doctors will order a CT scan or PET scan before ordering bone scintigraphy.
Your doctor could have many reasons for ordering a bone scan, but they are usually performed to find the cause of persistent and unexplained bone pain. Skeletal pain can come from trauma and injury, certain diseases, or even cancer. Bone cancer is rare – most cancers start in other places in the body, but it is possible for them to metastasize to the bones. However, there are three types of cancers that originate in the bone: chondrosarcoma, Ewing sarcoma, and osteosarcoma. Luckily, if tumors are found in the bone, it is far more likely that they are noncancerous – less than one percent of all cancers are bone cancers.
Bone scan procedures are used to diagnose a wide range of issues. They can help a doctor find evidence of fractures, arthritis, joint and bone infections, and rare diseases that affect the bones, like Paget’s disease. This is a disorder in which bones cease to replace aged tissue with new tissue.
Stress fractures, which are tiny cracks in the bone caused by overuse or repetitive strain, are not usually visible in X-rays. Scintigraphy is typically the best option for revealing stress fractures, as well as hip fractures. Due to the complex shape of the hip and surrounding bones, these scans are usually the most effective way to find problems in the hips that could be hidden otherwise.
Bone scintigraphy always starts with an injection. Tracers (radioactive materials) are injected, usually into your arm. These tracers slowly make their way through your bloodstream and into your bones. This process may take up to four hours. The provider will most likely ask you to drink several glasses of water while you wait for the tracers to circulate completely. This is so you can empty your bladder before your test, which will help remove unabsorbed tracers from your system.
For the scan itself, you will lie down on a table. You must remain as still as possible while the camera captures the images. The camera is on a long arm that extends over the table, and will make several passes up and down the entire length of the table to capture images of your entire body. The tracers in your body emit gamma rays as the camera passes over them. The camera picks up radioactive energy and send it to a special computer, where the information is translated into images that depict the tissue in great detail.
No camera or devices makes contact with your body during the scan, so there is no pain involved. However, scans can take up to an hour, and lying still on a table for that long can result in some discomfort for some patients.
Depending on the parts of the body being scanned, total times can vary. However, whole-body scans generally take about an hour. There are no side-effects associated with scintigraphy, though you will be asked to drink plenty of fluids post-scan to eliminate the tracers more quickly. Your provider may ask you to continue drinking extra water for two days to make sure all the tracers get flushed out as soon as possible.
Scintigraphy can be used to explore various organs, but it is especially good at showing growth and repair within your bones, and for revealing abnormal metabolic activity. Abnormal cell metabolism is a strong indicator of cancer. If you’re getting a scan to follow-up on the progression of certain cancers, your provider might also opt for a PET or CT scan rather than a bone scan. PET scans can show details of cell metabolism in a variety of organs, and can pick up on abnormalities in other biochemical activities within your body as well.
Bone scans are considered completely safe. The amount of radioactive material contained in the tracer is so minute that it is not considered to be a risk of any kind. In extremely rare cases, the patient may be allergic to the tracer material. In the long run, the biggest risk faced during scintigraphy is slight discomfort during the injection of the tracer.
There is not much preparation required for a bone scan. There is no need to fast or restrict your water intake. Your doctor will likely ask you if you’ve taken any medications containing bismuth in the 48 hours leading up to your scan. Bismuth, an ingredient in over-the-counter medicines that help relieve gastrointestinal issues, like Pepto-Bismol, can interfere with bone scan readings.
Likewise, barium contrast, which is used in some X-ray procedures, can also interfere with scintigraphy readings and results. Let your doctor know if you’ve undergone a procedure that includes barium; it can remain in your system for several days after the contrast was administered.
While the level of radiation in scintigraphy is small, bone scans are generally not performed on pregnant or nursing women, as it is unknown how even trace amounts of radiation can impact a fetus’s or a baby’s development.
You’ll be asked to remove all jewelry before the exam, and will most likely be instructed to wear a hospital gown rather than your clothing.
After you complete your bone scan, the radiologist will send the images to your provider. Your doctor will then interpret the results and hopefully come back to you with a diagnosis. One of the first things your doctor will look for are “hot spots.” These are the areas of the scan that contain large or unusual dark spots. A certain amount of hot spots is normal, especially around the joints. However, irregular, asymmetrical, or unusually placed hot spots can be an indication of a serious problem, such as the presence of cancer cells.
Depending on the results of your bone scan, your provider may want you to follow-up with a different type of diagnostic imaging. If you’re worried about the cost of bone scans and other forms of imaging starting to add up too quickly, look for diagnostic imaging at Tripment.com. Like many forms of imaging, bone scan costs can vary from state to state, but Tripment has a one-stop shop where you can compare costs for diagnostic imaging like MRIs, CT scans, and PET scans, letting you follow up on your scintigraphy results without having to rely on insurance to cover the costs. Tripment negotiates directly with diagnostic imaging facilities so you can get an out-of-pocket MRI for as little as $360.