Mammogram: what to expect, how to prepare, 3D vs 2D

Who is screened

The USPSTF recommends a mammogram every 2 years for women 40 to 74 (grade B, 2024). (USPSTF, 2024) Other groups differ on how often; see breast cancer screening. A screening mammogram is for people without breast symptoms. If you have a lump or another change, tell your provider: you may need a diagnostic mammogram, which takes more pictures. (ACS, 2026)

Booking

Pick a facility you can use year after year, so it keeps your records and can compare pictures over time. (ACS, 2026)
Check that it is certified: under federal law (MQSA) every mammography facility must be certified by the FDA or an FDA-approved state agency and display its certificate. If you do not see it, ask. (FDA, 2023)
If you have periods, choose a time when your breasts are less likely to be swollen or tender, which usually means avoiding the week before your period. (ACS, 2026) (RadiologyInfo, 2025)
At a new facility, bring earlier mammograms with dates, biopsy results and reports of other breast procedures. (ACS, 2026)

On the day

Wear a separate top and bottom, so you only take off your top and bra. (ACS, 2026)
No deodorant, antiperspirant, powder, lotion or perfume under your arms or on your breasts: they can show up as white spots on the pictures. Skip jewelry such as necklaces or nipple piercings. (ACS, 2026)
Tell the technologist about any breast changes, breast implants, trouble standing still without a cane or walker, and if you are breastfeeding or might be pregnant. (ACS, 2026)

What happens

You undress above the waist in private and wear a wrap; only you and the technologist are in the room. You stand at the machine, the technologist places one breast on it, and a plastic plate presses the breast flat for about 10 to 15 seconds while the picture is taken. Then the breast is pressed from the side for a second view, and the same is done on the other side. (ACS, 2026) Pressing the breast flat spreads the tissue so small changes are less likely to be hidden, allows a lower x-ray dose and keeps the breast still. You may need to hold your breath for a few seconds. (RadiologyInfo, 2025) People with implants or larger breasts may need more pictures. (ACS, 2026)

Does it hurt? You will feel pressure. Some people feel discomfort and for some it is painful. Tell the technologist if it hurts: they can adjust the compression. (ACS, 2026) (RadiologyInfo, 2025)
How long: about 20 minutes for the whole procedure, according to the American Cancer Society; about 30 minutes for the exam process, according to RadiologyInfo. You may be asked to wait until the radiologist confirms all the pictures needed were taken. (ACS, 2026) (RadiologyInfo, 2025)
Breast implants: keep getting mammograms, and tell the facility. Implants can hide some tissue, and special implant displacement views may be used. Most people with implants after a mastectomy do not need a mammogram of the reconstructed breast. (NCI, 2025)

2D or 3D (tomosynthesis)

A 3D mammogram (digital breast tomosynthesis, DBT) is done the same way, but the x-ray moves in a small arc over the breast to take many pictures that a computer builds into thin slices. (ACS, 2026) (NCI, 2025) The USPSTF says both digital (2D) and 3D mammography are effective for screening. (USPSTF, 2024) The NCI says 3D combined with standard mammography finds more tumors than standard mammography alone, but it is still unknown whether it lowers deaths from breast cancer more. (NCI, 2025) RadiologyInfo adds that large studies found fewer callbacks with 3D. (RadiologyInfo, 2025) Not every digital machine can do 3D. (RadiologyInfo, 2025)

Radiation, in plain terms

A mammogram uses a low dose of x-rays, and no radiation stays in your body afterward. The dose of some 3D systems is slightly higher than a standard mammogram, but within FDA-approved safe levels; some are very close to it. (RadiologyInfo, 2025) A diagnostic mammogram takes pictures from more angles, so its dose is higher than a screening one. (NCI, 2025)

Results

Some centers go over the results with you right after the test; others let you know within a few days. A full report goes to your provider, and results may appear in your patient portal before your provider contacts you. If you have not heard from your provider within 10 days, do not assume the mammogram was normal. (ACS, 2026) The facility must send you an easy-to-understand summary within 30 days. (FDA, 2023) Since September 10, 2024, when the result is suspicious or highly suggestive of cancer, the summary must reach you within 7 days of the reading. (FDA, 2024) Only 2 to 4 of every 1,000 screening mammograms lead to a breast cancer diagnosis. (ACS, 2026) What the BI-RADS numbers and a callback mean: mammogram results. About the density notice: dense breasts.

Cost and coverage

Health plans under the Affordable Care Act must cover screening mammograms every 1 to 2 years from 40 with no copay, coinsurance or deductible; check with your plan about a diagnostic mammogram. (NCI, 2025) Medicare Part B covers one baseline mammogram for women 35 to 39 and a screening mammogram every 12 months from 40, at no cost if the provider accepts assignment; for a diagnostic mammogram you pay 20% of the Medicare-approved amount after the Part B deductible. (Medicare.gov) Without insurance, the CDC's National Breast and Cervical Cancer Early Detection Program offers screening to women with low income. (NCI, 2025) More: free screenings without insurance.

Questions people ask

Does a mammogram hurt?

You will feel pressure while each breast is compressed for about 10 to 15 seconds per picture. Some people feel discomfort, and for some it is painful. Tell the technologist if it hurts so they can adjust the compression; booking when your breasts are least tender can help. (ACS, 2026) (RadiologyInfo, 2025)

How long does a mammogram take?

The American Cancer Society says the whole procedure takes about 20 minutes; RadiologyInfo says the exam process should take about 30 minutes. You may be asked to wait until the radiologist confirms all the needed pictures were taken. (ACS, 2026) (RadiologyInfo, 2025)

Why can I not wear deodorant before a mammogram?

Deodorant, antiperspirant, powder, lotion and perfume under your arms or on your breasts can show up as white spots on the pictures and make the mammogram hard to read. (ACS, 2026)

Is a 3D mammogram better than a 2D one?

The USPSTF says both digital mammography and 3D mammography (tomosynthesis) are effective for screening. The NCI says 3D combined with standard mammography finds more tumors than standard mammography alone, but it is not yet known whether it saves more lives. (USPSTF, 2024) (NCI, 2025)

When do I get my mammogram results?

It depends on the center: some review results with you right after, others tell you within a few days. The facility must send you an easy-to-understand summary within 30 days; under the 2024 federal rule, when the result is suspicious or highly suggestive of cancer, it must reach you within 7 days of the reading. If you have not heard from your provider within 10 days, do not assume the result was normal. (ACS, 2026) (FDA, 2023) (FDA, 2024)

Screening mammogram: what to expect