What you can expect

During the test

When you arrive for your molecular breast imaging test, you'll be asked to undress above the waist. You'll receive a gown to cover yourself until the test begins. You may also receive a blanket to keep your chest warm, as being warm and relaxed can improve the uptake of the tracer by your breast tissue.

To begin your molecular breast imaging test, you'll receive an injection of the radioactive tracer into a vein in your arm. The tracer contains a substance that's quickly absorbed by fast-growing cells, such as cancer cells. The tracer emits gamma rays that are detected by two small gamma cameras that are part of the molecular breast imaging system.

You'll be seated in a chair facing the molecular breast imaging system, which looks similar to a mammogram machine. You'll be asked to open or remove your gown and place one breast on the flat surface of a gamma camera in front of you. You may need to lean forward a little, and pillows may be placed behind your back to make this more comfortable.

The flat surface of a second gamma camera will be lowered on top of your breast. The compression is light — just enough to hold your breast in place during the test — and shouldn't be painful or uncomfortable.

You will sit still for 10 minutes as the gamma cameras record the activity of the tracer. Your breast will be repositioned for a second image, and you'll be asked to sit still again for 10 minutes as the image is created.

If you're having both breasts imaged, your other breast will be positioned in the imaging machine and the process will be repeated. Two images are created of each breast, and each image takes about 10 minutes. In total, you'll be asked to sit still for 40 minutes, though you can get up and stretch between images — every 10 minutes. Women with larger breasts may need additional images.

After the test

Once the test is complete, you'll be asked to wait while a technologist checks the quality of the images. If there are problems with the images, you may have to repeat part of the test.

Afterward, you may dress and resume normal activity.