MBI (shown right) and 3D (shown left) are both superior to standard 2D mammography but that’s where the similarity ends. 3D detects slightly more cancers than standard 2D mammography, but MBI is much better in detecting breast cancer in women with dense breast tissue.

MBI and 3D mammograms are completely different technologies

• MBI: Rather than a simple picture of breast tissue, MBI scans show differences in the activity of breast tissue. Cancer cells that are abnormally dividing show clearly as a spot on the scan. MBI finds 3 times as many tumors as standard mammography.
• 3D: Mammograms capture individual images, which are combined to simulate slices of breast tissue. The photos show tumors as white spots, but because dense breast tissue also shows up as white, it can be difficult to see white tumors within the white tissue.

They show different things

• MBI: Does a better job distinguishing between normal dense tissue, benign tumors and cancerous tissue. MBI not only finds more breast cancers but also has fewer false positives.
• 3D: Multiple image “slices” can be viewed, which requires more interpretation. Cancer and dense tissue can still appear similar. There are more false positives with 3D than with MBI.

The current protocol is to use them together

• The two tests are complementary in many ways. MBI detects three times as many cancers as mammography alone. For women with dense breasts, the general recommendation is 3D plus MBI.

New laws provide notice to women with dense breasts

• In most states, mammography providers are now required to inform women if they have dense tissue. This notice enables them to consider the more accurate MBI scans instead of relying on mammography alone. Several more states have similar legislation pending, including Wisconsin.

MBI myths

MBI is a new, experimental technology (FALSE)

MBI was developed by Mayo Clinic and cleared for safety by the U.S. Food and Drug Administration in 1999. In 2008, a landmark study concluded that MBI was more effective than a mammogram for women with dense breasts. In 2015 and 2017, two major studies confirmed the effectiveness of MBI in combination with mammography.

The newest generation of MBI imaging is quite different from systems available even five years ago (the MBI unit at Mayo Clinic Health System in La Crosse is the latest technology as of October 2017). Testing and innovation will continue, but MBI is a mature, safe technology.

MBI is expensive (FALSE)

Cost is in the same range as a 3D mammogram.

MBI uses a high dose of radiation (FALSE)

Over time, MBI tracer dosage has been reduced considerably and is now comparable to a mammogram. It is also less than natural radiation levels absorbed annually from the environment (called background radiation). 

MBI and 3D mammography are both in the low-dose range, when compared to most other radiology examinations.

Questions to ask your provider

Q: Do I have dense breasts? (50% of women do)

If you do have dense breasts, ask the following:

Q: What can I do to lower my risk of getting breast cancer?
Q: What screening tests are best for women with dense breasts?
Q: How often should I be screened?
Q: Do dense breasts run in the family?

For more, see the Center for Breast Care web page.