Mammograms are considered the standard of care to screen for breast cancer. In addition, mammograms are used to diagnose and evaluate a new suspicious finding or follow someone with a personal history of breast cancer. A mammogram uses compression and x-ray technology to image your breast. Undergoing a mammogram has the same radiation exposure as an individual would expect to receive from natural (or background) radiation exposure over 7 weeks. However, if you suspect you are pregnant, you should notify the technician.

Screening mammograms are typically done every year to check the breasts for any early signs of breast cancer.

Diagnostic mammograms focus on getting more information about a specific area (or areas) of concern — usually due to a suspicious screening mammogram or if the patient feels a palpable lump/mass.

Doctors and mammogram equipment

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About Mammograms

About Mammograms

Current evidence confirms that mammograms offer substantial benefit for women in their 40s and older to detect cancer earlier. Mammograms are able to capture tiny changes to the breast, such as calcifications, that cannot be seen on alternative imaging.

It is important to have your mammogram done annually at the same facility. This will aid the radiologists in noticing any changes to your breast tissue and help catch any suspicious findings early on. Still, there are some limitations, due to increased breast density, and your provider may order additional testing to help completely evaluate your breasts.

Mammograms are recommended annually for women over the age of 40. Talk to your provider regarding your personal risk for developing breast cancer to determine if screening should begin before the age of 40 or additional imaging should be added.

Mammogram research
Digital Mammography

Digital Mammography

At the Margie Petersen Breast Center, each mammography unit is equipped with a digital receptor. This allows the mammograms to utilize dedicated computers instead of conventional X-ray film. The mammograms, performed by a technologist, are then viewed electronically by one of our breast radiologists on computer screens designed for optimal viewing. In addition, the images are read in conjunction with a CAD (computer-aided detection) software, which calculates the density of your breast tissue and flags potential abnormal areas for the radiologist to take a closer look at.

Digital mammography provides a clearer and more accurate image of the breast than analog or film mammography. Digital mammograms are faster than analog film mammograms, because there is no film to develop. The image can be sent immediately to the radiologist for viewing. If the image is unclear, you will be told about it right away, and the image can be retaken. This helps reduce mammogram callbacks and, overall, stress on patients.

This leading-edge technology is the first step in the breast imaging process. If an abnormality is found, the area of concern can be imaged with additional mammograms (called spot compression). Imaging and/or procedures such as an ultrasound, biopsy, and/or MRI may be necessary to evaluate the finding, as well. These highly sophisticated and integrated services create a more efficient process allowing shorter examination times, quicker results, and ultimately more convenience for the patient.

Doctors looking at mammogram results
Breast Density

Breast Density

On April 1, 2013, the state of California became the fifth state to enact a dense breast notification law (Senate Bill 1538). This law requires physicians to inform patients if their breasts appear dense on mammography. It was enacted to raise awareness about dense breasts, but also raises questions about the relevance of breast density and what recommendations we should make to patients.

Breast density is typically determined visually by the radiologist and is subjective. It is a measure used to describe the proportion of the different tissues that make up a woman’s breasts. It compares the area of breast and connective tissue seen on a mammogram to the area of fat. Breast and connective tissue are denser than fat and this difference shows up on a mammogram.

  • High breast density means there is a greater amount of breast and connective tissue compared to fat.
  • Low breast density means there is a greater amount of fat compared to breast and connective tissue.

Breast density is classified using a scoring method developed by the American College of Radiology:

  • Level 1 = Entirely fatty tissue; less than 25 percent density
  • Level 2 = Scattered fibrograndular densities; less than 25-50 percent density
  • Level 3 = Heterogeneously dense; 50-75 percent density
  • Level 4 = Extremely dense; greater than 75 percent density

Having dense breasts has been associated with an increased risk of breast cancer, but it does not appear to worsen survival from cancer. In fact, when tumors are detected later in women with dense breasts, these tumors are typically no more aggressive or more difficult to treat, and survival is the same.

Breast density appears to decrease with age but can also be increased with the use of post-menopausal hormone replacement therapy. Since the density of breast tissue has been shown to increase risk for breast cancer, consideration of additional imaging like screening ultrasound or MRI may be helpful for women with dense breasts.

Tomosynthesis “3D” Mammogram

Tomosynthesis “3D” Mammogram

During a tomosynthesis, or 3D mammogram, multiple low-dose images known as “slices” of the breast are acquired at different angles, allowing us to see the breast in a way never before possible. While a past 2D mammogram usually takes two x-ray views of the breast from different angles (side to side and top to bottom) the 3D mammogram allows the radiologist to have a complete picture of the breast to investigate.

In addition, the 3D mammogram is better at viewing abnormalities in dense breast and is more comfortable for the patient due to less needed compression. At the Margie Petersen Breast Center, we have transitioned to all digital tomosynthesis mammography to help detect cancer faster and more accurately.


Scheduling a Mammogram or Ultrasound after a COVID vaccine

The Society of Breast Imaging recently reported that the COVID vaccine can cause temporary enlargement of the underarm (axillary) lymph nodes. This is a normal reaction to some vaccinations, however this can lead to unnecessary additional workup with ultrasound and or biopsies. It has been recommended to avoid breast imaging (mammograms/ultrasound MRI) immediately after a vaccine injection. In order to eliminate unnecessary workups, after receiving the vaccine, we will follow these guidelines when scheduling a mammogram or ultrasound:

Screening or Diagnostic Mammograms and Ultrasounds

In addition to the standard COVID screening questions we will also ask patients, “Have you had or will you be having a COVID vaccine?”

If the answer is “yes” we will schedule your breast screening appointment at least 1 day BEFORE the FIRST vaccine dose or at least 2 weeks AFTER the SECOND vaccine dose.

We hope this approach will avoid unnecessary tests for our patient who have normal reactive lymph nodes.

This only applies to patients who do not have breast symptoms and or concerns. For patient with a breast concern, we will schedule as normal, and our technologist will get your medical history.

Breast Cancer Screening Methods and Myths Webinar

Watch our breast cancer doctors at the Margie Petersen Breast Center at Providence Saint John’s, discuss the different types of breast cancer screening methods including, breast exams, mammography, ultrasounds, MRI, and biopsy, as well as share the facts for all the common breast cancer myths you’ve heard.

Meet Our Breast Health Care Team

The Margie Petersen Breast Center at Providence Saint John’s Health Center brings you some of the finest breast health and cancer care in Southern California.

Meet Our Breast Health Experts

Margie Petersen Breast Team


The Breast Health Clinic can be reached at (310) 582-7209. If you have questions regarding a new symptom or want to make an appointment for evaluation please call and a staff member will assist with navigating you in the right direction.

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