Scintimammography is a nuclear medicine imaging test that uses a radioactive material (known as a radioactive isotope) and a special camera to take images of the breast. This test may also be called breast scintigraphy.
Breast cancer cells attract more radioactive material than normal or benign (non-cancerous) cells. This is because cancer cells divide and grow more rapidly. The radioactive isotope gathers in larger amounts in cancer cells because of this rapid growth.
Why scintimammography is done
Scintimammography is not commonly used. It does not replace mammography, which is the standard imaging test used to diagnose breast cancer. At present, scintimammography is considered a second-line diagnostic tool. It may be used in some women to assess breast abnormalities after a mammogram.
Scintimammography may be done:
- to check breast lumps that do not show up clearly on a mammogram because of:
- scar tissue from previous surgery or radiation therapy
- dense breast tissue
- breast implants
- when multiple tumours are seen in the breast
- to scan the lymph nodes in the armpit (axilla) to see if they contain cancer
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How scintimammography is done
Breast scintimammography is usually done as an outpatient procedure in the nuclear medicine department of a hospital. The test takes about 45–60 minutes.
No special preparation is needed before the test, but it should not be done until:
- 2 weeks after a fine needle aspiration
- up to 6 weeks after a core needle or excisional biopsy.
A radioactive isotope is injected into a vein in the arm. The most commonly used isotope is technetium-99 m (Tc-99m) sestamibi. Technetium-99m is also known as Miraluma, so this test may also be called Miraluma test.
- Shortly after the injection, the woman lies face down on a special imaging table that has openings so the breasts can hang down. The breast is not compressed.
- The radioactive isotope produces invisible rays that are read by a special camera.
- Images of the breast are taken from various angles and positions. The person may be asked to lay on the back or sit up with the arms above the head.
After the scan, the radioactive material quickly loses its radioactivity. It passes out of the body through the urine or stool (feces). Depending on the type of radiopharmaceutical used, it may take a few hours or days to completely pass out of the body.
- Drinking fluids after the procedure helps flush the radiopharmaceutical from the body.
- Special instructions may be given to take special precautions after urinating, to flush the toilet twice and to wash the hands thoroughly.
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Potential side effects
The dose of x-rays or radioactive materials used in nuclear medicine imaging can vary widely. Dose depends on the type of procedure and body part being examined. In general, the dose of radiopharmaceutical given is small and people are exposed to low levels of radiation during the test. The potential health risks from radiation exposure are low compared with the potential benefits. There are no known long-term adverse effects from such low-dose exposure.
Some potential side effects that might occur include:
- Bleeding, soreness or swelling may develop at injection site.
- Allergic reactions to the radiopharmaceutical may occur, but are extremely rare.
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What happens if a change or abnormality is found
If an abnormality is found, the doctor will decide if further tests are needed.
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Limitations of scintimammography
Activity from other organs, such as the heart or liver, may interfere with the test and affect the scintimammography results. Scintimammography may not detect very small tumours, such as those less than 1 cm (1/2 inch) in diameter.
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