PET Scan, or Positron Emission Tomography Scan, is a specialized imaging test used to detect cancer cells. During a PET Scan, a radioactive substance is given through an intravenous (IV) injection. The substance used in PET Scans is fluorine-18 fluorodeoxyglucose (FDG) and is called a tracer. FDG goes to areas of the body where cells are using large amounts of glucose (areas that are metabolically active). Because cancer cells are amongst the most active cells in the body, the FDG tracer settles in malignant masses. FDG releases positrons, so these areas will show up “hot” on the positron detecting plates.
Breast PET Scan is also known as PEM, positron emission mammography. The positron detecting plates resemble the compression system used in mammography. During a PEM breast biopsy, the patient is seated. Unlike mammography, Breast PET Scan does not require compression for the exam, only gentle immobilization between the positron detecting plates. Areas of concern detected in the breast by PEM can be biopsied using similar minimally invasive biopsy devices employed in ultrasound guided core biopsies and stereotactic breast biopsy (vacuum assisted core needle biopsy). The breast tissue removed will also test “hot” when it is placed under the positron detecting plates, so the physician performing the biopsy can be confident that the correct area was sampled.
Breast PET Scan is both very sensitive and very specific. PET Scan for Breasts is obtained in minutes and is easily interpreted. It currently has been approved for patients who have been diagnosed with breast cancer. PEM may help with planning a patient’s breast cancer surgery after a breast cancer diagnosis. PEM may also detect breast cancer recurrence.
While PET Scan for Breasts does involve the use of a radioactive material, the dose of radiation received by the patient is less than half the radiation dose a patient receives from a chest CT scan. PEM cannot be used in diabetics, because of their abnormal glucose metabolism. An example of a breast cancer detected by Breast PET Scan that was not detected on mammogram is seen below:
Mammogram with Undetected Right Breast Cancer:
Same Patient with Breast Cancer of Right Breast Detected by Breast PET Scan:
Images courtesy of Dr. Kathy Schilling, Medical Director of Lynn Women’s Health and Wellness Institute, Boca Raton, Florida.