Mammography: Breast Cancer Screening & What to Expect

What Is Mammography and How Does It Work?

Mammography is a specialized X-ray imaging technique designed specifically for examining breast tissue. It uses low-dose radiation to create detailed images of the internal breast structure, allowing radiologists to detect abnormalities such as tumors, calcifications, and cysts that may indicate breast cancer or other conditions.

Mammography represents one of the most important advances in breast cancer detection and remains the gold standard screening tool recommended by medical organizations worldwide. The technique was developed in the 1960s and has undergone significant improvements in image quality and radiation dose reduction over the decades. Modern digital mammography systems produce high-resolution images that can be enhanced, magnified, and analyzed using computer-aided detection systems.

The fundamental principle behind mammography involves passing X-rays through breast tissue and capturing the resulting image on a detector. Different types of tissue absorb X-rays differently: dense tissue such as glandular tissue appears white on the image, while fatty tissue appears darker. Tumors and calcifications typically appear as bright white spots or areas because they are denser than surrounding normal tissue.

Understanding how mammography works helps patients appreciate why certain aspects of the procedure, such as breast compression, are necessary. When the breast is compressed, it spreads the tissue more evenly, allowing X-rays to penetrate more uniformly and producing clearer images. Compression also reduces the radiation dose needed because the X-rays travel through less tissue, and it minimizes motion blur during the brief exposure time.

Types of Mammography

There are several types of mammographic examinations, each serving different purposes in breast health care. Screening mammography is performed on women without symptoms as a preventive measure to detect cancer early. Diagnostic mammography is used when there are symptoms or abnormal findings from a screening exam that require further investigation. Diagnostic mammograms typically involve more images and may include spot compression or magnification views.

3D mammography, also known as digital breast tomosynthesis, is an advanced technique that takes multiple X-ray images from different angles and creates a three-dimensional reconstruction of the breast. This technology is particularly helpful for women with dense breast tissue, as it can reveal abnormalities that might be hidden on standard 2D images. Studies have shown that 3D mammography can increase cancer detection rates while reducing false-positive callbacks.

Who Should Have Mammography?

Screening recommendations vary by country and medical organization, but most guidelines suggest that women at average risk begin regular mammography screening between ages 40 and 50, continuing until at least age 74. The frequency of screening is typically every one to two years. Women with higher risk factors, such as a family history of breast cancer, known genetic mutations (BRCA1 or BRCA2), or previous breast abnormalities, may need to start screening earlier and have more frequent examinations.

It is important to discuss your individual risk factors with your healthcare provider to determine the most appropriate screening schedule for your situation. Factors that may influence screening recommendations include age, family history, breast density, previous breast biopsies, and genetic predisposition.

How Should You Prepare for a Mammogram?

Preparing for a mammogram involves avoiding deodorant, powder, or lotion on your breasts and underarms on the day of the exam, as these products can appear as white spots on images. Inform the staff if you are breastfeeding, have breast implants, or are taking blood pressure medications.

Proper preparation for your mammogram appointment helps ensure the best possible image quality and a smoother experience. While the examination itself is relatively simple, taking a few steps beforehand can make a significant difference in both the technical quality of your images and your personal comfort during the procedure.

The most important preparation step is to avoid applying any products to your chest area on the day of your examination. Deodorants, antiperspirants, powders, lotions, creams, and perfumes can contain metallic particles, particularly aluminum, which can appear as white specks or artifacts on mammogram images. These artifacts can obscure actual breast tissue abnormalities or, conversely, be mistaken for suspicious calcifications. If you accidentally apply these products, the facility may ask you to wash the area before the examination.

Scheduling your mammogram at the right time of your menstrual cycle can improve your comfort during the examination. If you are premenopausal and experience breast tenderness related to your menstrual cycle, try to schedule your appointment during the week following your period, when breast tissue is typically least sensitive. This timing can make the compression process more comfortable without affecting image quality.

What to Tell Your Healthcare Team

Before your mammogram, it is essential to inform the radiographer and radiologist about certain medical conditions and medications that may affect your examination or interpretation. If you are breastfeeding, the breast tissue will be denser due to milk production, which can make images more difficult to interpret. While mammography can still be performed during breastfeeding, nursing or pumping just before the examination can help reduce breast density and improve image clarity.

If you take blood pressure medications or are being treated for prostate cancer, inform the staff as certain medications can affect breast tissue. Additionally, if you have breast implants, special techniques called implant displacement views are required to visualize as much natural breast tissue as possible. Bring a list of your current medications to your appointment.

If you have had previous mammograms at different facilities, request that those images be sent to your current facility or bring them with you. Comparing current images to previous ones helps radiologists identify changes over time and can significantly improve diagnostic accuracy.

What Happens During a Mammogram?

During a mammogram, you undress from the waist up and stand near the X-ray machine. A radiographer positions your breast on a flat plate, which is then compressed by another plate from above. Images are taken from multiple angles, with each compression lasting only a few seconds.

Understanding what to expect during a mammogram can help reduce anxiety and make the experience more comfortable. The examination is performed by specially trained radiographers (also called mammography technologists or radiologic technologists) who are experts in positioning patients and operating the equipment to obtain optimal images.

Upon arriving at the breast imaging facility, you will be asked to undress from the waist up and put on a hospital gown that opens in the front. You should remove any jewelry from around your neck and chest area. The radiographer will review your medical history and ask about any breast symptoms, previous surgeries, or family history of breast cancer.

The mammography machine consists of a flat platform where your breast is placed and a compression paddle that lowers from above. For each image, the radiographer will carefully position your breast on the platform, adjusting your arm and body position to ensure all breast tissue is included. The compression paddle then lowers slowly, spreading the breast tissue evenly between the two surfaces.

The Compression Process

Breast compression is a critical part of mammography that serves several important purposes. First, it spreads the breast tissue so that overlapping structures do not hide potential abnormalities. Second, it holds the breast still during the X-ray exposure, preventing motion blur. Third, it allows the use of lower radiation doses because X-rays pass through less tissue when the breast is flattened.

The compression can feel uncomfortable and may cause some pain, particularly for women with sensitive breasts. However, the compression for each image lasts only a few seconds. The radiographer will apply compression gradually and ask you to hold your breath briefly while the image is captured. If you experience significant pain, inform the radiographer, who may be able to adjust the technique while still obtaining diagnostic-quality images.

A standard screening mammogram includes two views of each breast: a top-to-bottom view (craniocaudal or CC view) and an angled side view (mediolateral oblique or MLO view). This means four images are typically taken in total. Diagnostic mammograms may include additional views depending on what the radiologist needs to evaluate.

Duration and What Happens After

The actual imaging process takes approximately 10 to 15 minutes, though you should plan for your entire appointment to last up to an hour. This additional time accounts for registration, changing, the possibility of additional images, and potentially other examinations such as ultrasound if needed.

After the images are taken, you may be asked to wait briefly while a radiologist reviews the images to ensure they are of adequate quality. In some facilities, particularly those performing diagnostic mammograms, the radiologist may request additional views or an ultrasound examination to further evaluate any areas of concern seen on the initial images.

When Is Contrast-Enhanced Mammography Used?

Most mammograms do not require contrast material, but contrast-enhanced mammography may be used when clearer images are needed. Contrast medium is a liquid administered through an intravenous line in the arm that helps highlight areas of increased blood flow, which can indicate tumors.

Contrast-enhanced spectral mammography (CESM) is a relatively newer technique that combines mammography with intravenous contrast administration. Similar to contrast-enhanced MRI, this technique takes advantage of the fact that tumors often have increased blood supply compared to normal tissue. When iodine-based contrast material is injected, it preferentially accumulates in areas of higher blood flow, making tumors more visible on the images.

CESM may be recommended in several situations: when standard mammography or ultrasound results are inconclusive, for patients with dense breast tissue that makes standard mammography less sensitive, for evaluating the extent of known breast cancer before surgery, or as an alternative for patients who cannot undergo breast MRI. The technique has shown promise in detecting cancers that might be missed on standard mammography.

If your examination requires contrast, you will receive an injection through a small tube (intravenous catheter) placed in a vein in your arm. The contrast is injected before the mammogram images are taken. Most people feel a warm sensation when the contrast is injected, which is normal and temporary. The contrast is eliminated from the body through the kidneys over the next 24 hours.

Considerations for Contrast Use

Before receiving contrast, the healthcare team will ask about allergies, particularly to iodine or contrast materials used in CT scans. They will also inquire about kidney function, as contrast is filtered by the kidneys. Patients with impaired kidney function may not be suitable candidates for contrast-enhanced mammography. If you have ever had an allergic reaction to contrast material, inform your healthcare team, as premedication may be necessary.

How Safe Is Mammography Radiation?

The radiation dose from mammography is very low, approximately 0.4 millisieverts (mSv) per examination, equivalent to about 7 weeks of natural background radiation. Modern digital equipment is designed to minimize radiation while maintaining image quality.

Concerns about radiation exposure from mammography are understandable, but it is important to put the risks in perspective. The radiation dose from a screening mammogram is extremely low and considered safe for routine use. To contextualize this dose, humans are constantly exposed to background radiation from natural sources such as cosmic rays, radon in the air, and radioactive elements in the earth. The dose from one mammogram is comparable to the natural background radiation a person receives over about seven weeks of normal daily life.

Modern digital mammography systems are engineered to deliver the lowest radiation dose possible while still producing high-quality diagnostic images. The equipment undergoes regular quality control testing to ensure that radiation output is within prescribed limits. Additionally, lead shielding may be used to protect other parts of the body, though the radiation beam is highly focused on the breast area.

For women in recommended screening age groups, the benefits of early breast cancer detection through mammography significantly outweigh the minimal radiation risks. Early detection can lead to less aggressive treatment, better survival rates, and improved quality of life. Multiple large-scale studies have demonstrated that mammography screening reduces breast cancer mortality by 20-40% in women aged 50-69.

Radiation in Pregnant Women

If you are or might be pregnant, inform the healthcare team before any X-ray examination. While the radiation from mammography is directed at the breast and not the abdomen, and the dose to a fetus would be negligible, mammography is typically postponed during pregnancy unless there is an urgent medical need. Alternative imaging modalities such as ultrasound, which uses no radiation, may be preferred for evaluating breast concerns during pregnancy.

What Should You Expect After a Mammogram?

After a mammogram, you may experience mild breast tenderness where the compression occurred, but this typically resolves within a day. There are no restrictions on activities after the examination, and you can return to normal daily routines immediately.

The mammogram itself causes no lasting effects, and you can resume all normal activities immediately after your appointment, including driving, working, and exercise. Some women experience mild tenderness or aching in the breasts after the compression, similar to the feeling before a menstrual period. This discomfort usually subsides within a few hours to a day and can be relieved with over-the-counter pain medication if needed.

If you received contrast material during your examination, you may be advised to drink extra fluids to help your kidneys flush the contrast from your system. Otherwise, there are no special post-procedure instructions, and you can eat, drink, and take medications as usual.

Understanding Post-Procedure Feelings

Many women experience some anxiety while waiting for their mammogram results. This is completely normal, especially if this is your first mammogram or if you have been called back for additional imaging in the past. Remember that most mammograms show normal results, and even when additional tests are needed, the vast majority of findings turn out to be benign (not cancerous).

When and How Will You Receive Your Results?

Results are often available the same day if a radiologist reviews images immediately, and you may receive your results during your visit. Otherwise, results are typically sent by letter within one to two weeks. Abnormal findings require additional imaging in about 10% of cases, but most turn out to be benign.

The timeline for receiving mammogram results varies by facility and the type of examination performed. Many modern breast imaging centers have radiologists on-site who review images immediately after they are taken. In these settings, you may receive your results before leaving the facility. This immediate-read approach reduces anxiety and allows for same-day additional imaging if needed.

In other settings, particularly at screening centers that process high volumes of mammograms, images may be batch-reviewed by radiologists at a later time. In these cases, results are typically communicated by letter within one to two weeks. Some facilities also offer online patient portals where results can be accessed electronically.

Your mammogram results will be categorized using the BI-RADS (Breast Imaging Reporting and Data System) scoring system, which ranges from 0 to 6. A score of 1 indicates a negative (normal) exam, while a score of 2 indicates benign findings. Scores of 3 and above indicate varying levels of suspicion that may require follow-up imaging or biopsy. Your healthcare provider will explain what your specific BI-RADS score means and what, if any, follow-up is recommended.

What If Additional Testing Is Needed?

Receiving a callback for additional imaging can be stressful, but it is important to understand that this is relatively common and usually does not mean you have cancer. Approximately 10% of screening mammograms result in a callback for further evaluation. Of those called back, about 90% will have findings that turn out to be benign after additional imaging.

Additional evaluation may include more mammogram views (such as spot compression or magnification views), breast ultrasound, or in some cases breast MRI. If imaging studies show a suspicious finding, a biopsy (removing a small sample of tissue for examination under a microscope) may be recommended. This is the only way to definitively determine whether an abnormality is cancerous.

How Images and Data Are Stored

Your mammogram images and the results of your examination become part of your medical record. These records are typically stored digitally and can be accessed by your healthcare providers as needed. Results are also often recorded in national or regional quality registries that help evaluate and improve breast screening programs. These registries maintain strict confidentiality and use data only for quality improvement and research purposes.

How Can You Be Involved in Your Breast Health Care?

Being actively involved in your breast health care means understanding the information you receive, asking questions when you do not understand something, and knowing that you have the right to make informed decisions about your screening and treatment options.

Patient engagement is a crucial aspect of modern healthcare, and this is especially true for breast health. Being an informed and active participant in your care can lead to better outcomes and greater satisfaction with your healthcare experience. This involvement starts with understanding the purpose, benefits, risks, and alternatives associated with any medical procedure, including mammography.

Do not hesitate to ask questions before, during, and after your mammogram. If the healthcare provider uses medical terminology you do not understand, ask them to explain in simpler terms. You have the right to understand what is happening with your body and to participate in decisions about your care. Questions you might ask include: What does my breast density mean for my screening? How often should I have mammograms given my risk factors? What would happen if I chose not to have screening?

If you have difficulty understanding the information due to language barriers, you have the right to interpretation services. Many healthcare facilities provide professional medical interpreters at no cost to the patient. Similarly, if you have hearing impairment or other communication needs, inform the facility in advance so appropriate accommodations can be arranged.

Breast Self-Awareness

While mammography is an essential screening tool, being familiar with your own breasts is also important. Breast self-awareness means knowing how your breasts normally look and feel so that you can notice any changes. There is no longer a recommendation for formal monthly self-examinations, but being aware of your breasts and reporting any changes to your healthcare provider is encouraged.

Changes to report include new lumps or thickening, changes in breast size or shape, skin changes (dimpling, puckering, redness), nipple changes (inversion, discharge), or persistent pain. While most breast changes are not cancer, any new or unusual finding should be evaluated by a healthcare professional.