What is a nuclear medicine scan?
A nuclear medicine scan uses a small amount of radiation to create images of tissues, bones, and organs in the body. The radioactive material collects in certain areas of your body, and special cameras detect the radiation and create images that help your medical team diagnose and treat cancer and other diseases.
Other words for nuclear medicine test:
- Nuclear scan
- Nuclear imaging
- Radionuclide images
Why do you need a nuclear medicine scan?
Nuclear medicine tests are especially useful for cancer because they show tumors and track whether they have spread throughout the body. They are also a way to check how well the treatment is working. These scans have some limitations. For example, a scan shows areas of cancer. But your doctor needs more focused images (X-rays, CT scan, MRI) of those areas and should look for small tumors that are not visible on the nuclear scan. To know for sure if you have cancer, you may need a biopsy when the surgeon removes a small piece of the tumor for examination under a microscope.
Doctors also use nuclear medicine tests for conditions other than cancer:
- Heart disease
- Gastrointestinal disorders
- Glandular and hormonal problems.
- Neurological disorders (Alzheimer’s, epilepsy, Parkinson’s, and others)
What are some common uses of the approach?
Doctors use nuclear medicine imaging techniques to visualize the structure and function of an organ, tissue, bone, or body system.
In adults, nuclear medicine is used to:
- Visualize blood flow and heart function (such as myocardial perfusion test)
- Identify the extent of coronary artery disease and coronary stenosis.
- Assessing heart damage after a heart attack
- Evaluate treatment options such as heart bypass surgery and angioplasty.
- Evaluate the results of vascularization procedures.
- Identify heart transplant rejection
- Assess cardiac function before and after chemotherapy (Muga)
- Test the lungs for respiratory and circulatory problems.
- Assess differential lung function for lung reduction or transplant surgery
- Identify lung transplant rejection.
- Assess bones for fractures, infections, and arthritis.
- Assess for metastatic bone disease
- Evaluate painful prosthetic joints
- Evaluate bone tumors
- Identify sites for biopsy
Investigate brain abnormalities in patients with certain symptoms or disorders, such as seizures, memory loss, and suspicious abnormalities in blood flow.
- Identify the early onset of neurological disorders such as Alzheimer’s disease.
- Help with the surgical plan and identify the areas of the brain that are causing the seizures.
- Evaluate abnormalities in a chemical in the brain involved in movement control in patients with Parkinson’s disease or related movement disorders.
- Evaluation of recurrence of brain tumors, planning of surgery or radiation or localization for biopsy
Commonly used nuclear medicine scans for cancer:
- Pet scans. Here, your medical team injects radioactive sugar into your body. Your doctor can tell you where the cancer is because those cells absorb more sugar than normal cells. Your medical team may ask you to avoid sugar and especially sugary drinks in the hours before the test.
- PET / CT scans. It can detect common areas of cancer activity with a PET scan and learns more about those areas with a CT scan. But this is controversial: you give your doctor more information but expose you to more radiation.
- Bone scans. They can often detect bone changes that indicate cancer much earlier than other images. After the injection, a radioactive tracer builds up in the bone a few hours before the test begins.
- Thyroid tests. You ingest radioactive iodine, which travels through your bloodstream to accumulate in the thyroid gland, where it can help detect thyroid cancer. Tell your doctor if you are taking anything with iodine, such as medicine, cough medicine, seaweed, or heart medicine.
- Gallium scans. The test uses Tracer Gallium-67 to scan the entire body or look for organs specifically for signs of cancer. Where the scan accumulates gallium, it can be a sign of inflammation, infection, or cancer.
- Muga: This scan uses a radioactive liquid tracer to determine how much blood your heart is pumping through your body. This will help your doctor determine if your heart is strong enough for certain types of chemotherapy (cancer treatment). Some professionals can even use it to detect heart problems.
How does it work?
Most tests do not take an hour or more, however, you may need to wait a few hours while healthcare workers prepare you for the exam. These tests are usually done in the radiology or nuclear medicine department of the hospital. Some radioactive material gets into your body. Doctors call this substance a radioactive “tracer,” a radionuclide, or a radiopharmaceutical. Hospital staff may inject you with this tracer or give you a pill to swallow or inhale the gas. It can take a few seconds to several days for the marker to accumulate on the scanned body part.
Before scanning, all jewellery and metal that may interfere with the images will be removed. Although in some cases you can wear your own clothing, medical staff may ask you to wear a hospital gown. You lie on the table or sit in a chair for an examination. Technicians use a special camera or “scanner” on the appropriate parts of your body to detect the gamma rays from the tracer. Technicians may ask you to change positions to obtain different angles while the scanner is operating.
The scanner sends information to computer software that creates images, sometimes in three dimensions (3D) and with added colour for clarity. A specialist doctor called a radiologist will review the images and talk to your doctor about what they show.
What happens during a nuclear medicine test?
- You will be placed under/above the gamma camera. This camera detects radiation emitted by the patient after injecting the tracer.
- Testing generally begins as soon as the marker is injected.
- An image is produced that indicates the distribution of the marker throughout your body. It is analyzed in a special computer system.
- Some tests, for example, bone scans, require the patient to return within several hours to obtain delayed images.
- During the study, the patient was required to stay for several hours, usually an hour.
- The nuclear medicine physician will send your report and results to the prescribing physician for your next appointment.
- For infants and young children, stabilization devices are used to keep them stable.
- Kids can watch DVDs while scanning.
What are the benefits and risk factors?
- Nuclear medicine tests provide unique information, including details such as anatomical function and anatomy, that are often not available with other imaging techniques.
- Nuclear medicine scanners provide very useful diagnostic or treatment information for many diseases.
- The nuclear medicine test is less expensive and provides more accurate information than exploratory surgery.
- Nuclear medicine provides the ability to diagnose disease in its early stages, often by detecting abnormalities before symptoms appear or with other diagnostic tests.
- By determining whether the lesions are benign or malignant, PET scans can eliminate the need for a surgical biopsy or determine the best location for the biopsy.
- Positron emission tomography scans can provide additional information that is used to plan radiation therapy.
- Because only a small dose of radiotracer is used, nuclear medicine tests involve low radiation exposure. This is acceptable for diagnostic tests. Therefore, the risk of radiation is very low compared to the possible benefits.
- Nuclear medicine diagnostic procedures have been used for more than five decades and there are no long-term adverse effects from low-dose exposure.
- Therapeutic risks are always weighed against the possible benefits of nuclear medicine therapies. Your doctor will inform you of all the important risks prior to treatment and give you an opportunity to ask questions.
- Allergic reactions to radiation therapists are very rare and generally mild. Always inform the Nuclear Medicine staff about any allergies or other problems that have occurred during the previous Nuclear Medicine test.
- An injection of the radiotracer may cause slight pain and redness. It should be fixed faster.