A CT scan (also called a CAT scan, or computerized tomography scan) is an X-ray technique that gives doctors information about the body’s internal organs in 2-dimensional slices, or cross-sections. During a CT scan, you lie on a moving table and pass through a doughnut-shaped machine that takes X-rays of the body from many different angles. A computer puts these X-rays together to created detailed pictures of the inside of the body. Before the test, you need to have a contrast solution (dye) injected into your arm through an intravenous line. Because the dye can affect the kidneys, your doctor may perform kidney function tests before giving you the contrast solution.
Right now, CT scans are not used routinely to evaluate the breast. If you have a large breast cancer, your doctor may order a CT scan to assess whether or not the cancer has moved into the chest wall. This helps determine whether or not the cancer can be removed with mastectomy.
Your doctor might order CT scans to examine other parts of the body where breast cancer can spread, such as the lymph nodes, lungs, liver, brain, and/or spine. Generally, CT scans wouldn’t be needed if you have an early-stage breast cancer. If your symptoms or other findings suggest that the cancer could be more advanced, however, you may need to have CT scans of the head, chest, and/or abdomen. If advanced breast cancer is found, your doctor may order more CT scans during treatment to see whether or not the cancer is responding. After treatment, CT scans may be used if there is reason to think the breast cancer has spread or recurred outside the breast.
Some researchers are investigating whether breast CT scans could be a better screening tool than traditional mammography. During breast CT, you lie face down on a table while a CT scanner rotates around the breast. The total dose of radiation is the same as in a conventional mammogram. Research on breast CT for screening is still in the early stages, however.