Molecular breast imaging (MBI) is an FDA-approved technology used in addition to mammography in detecting breast cancers as small as 5mm. MBI uses an injection of a short-lived radiotracer (tc-99m sestamibi), at a relatively low dose, that accumulates more in cancerous tissue than it does in normal tissue. After the sestamibi has been administered, patients are imaged with a special scanner that can show where the sestamibi has accumulated. Because cancerous tissue accumulates more than normal tissue, the images show clear differentiation between tumors and surrounding tissue.
MBI is not a replacement for mammography; it is a supplemental exam that is used in addition to mammography. Dense breast tissue as an example could cause the findings from a mammogram to be inconclusive. Studies have also shown that mammograms are less effective in identifying cancers in dense breasts, because, in mammograms, cancers can appear white, which is the same for dense breast tissue. As a result, tumors may be masked by dense breast tissue and secondary screening may be helpful in ruling out the presence of cancer. Mammograms are best for structural anatomical imaging, while MBI offers molecular functional imaging enabling your doctor to see physiologic function for both healthy and diseased tissue.
Why would MBI be recommended?
Women with a complex/dense breast pattern may benefit from supplemental screening with MBI. Your physician may order an MBI exam if you have an indeterminate finding or if you have dense breasts and also have one or more of the following factors:-
- You are at moderate or high risk for breast cancer
- You are unable to have a breast MRI due to extreme claustrophobia
- You have a pacemaker, stent, or other implant in your body
- There are abnormalities on your mammogram/ US/or MRI
- You have breast implants
- You have had breast cancer and need a scan to detect any signs of recurrence
- You are in chemotherapy and need a scan to assess progress
What does the exam entail?
You will receive a relatively low dose injection of a short-lived radiotracer intravenously. The tracer accumulates in cancer cells and is not influenced by breast density. You can sit comfortably in front of the LumaGEM® molecular breast imaging system. Your breasts are mildly compressed between two special cameras, which take a series of images. Generally, these will be the same views that were taken during your mammogram to make comparison easier. The procedure takes about 30-45 minutes, and the images are available immediately for your doctor to review.
- A physician referral is necessary for all MBI exams. Women who still have a menstrual cycle should schedule their exam in days 1-10 of their menstrual cycle (day 1 is the first day of menstruation).
- You should have had a mammogram which will be used for comparison to the MBI exam.