We are doing this study because we want to find out if a new kind of breast imaging (called upright dedicated breast CT or UBCT) can help doctors to see the small structures in breast tissue more clearly in 3-D and without overlap.

The breast imaging device we will use in this study (UBCT) is not FDA-approved, so this is a research study. The machine has been designed to remove mammography-like breast compression and use radiation dose comparable to mammography. The breast CT device will take multiple x-ray pictures of the subjects breast in approximately 20 seconds and create a 3-D image of the breast. It does not compress or squish the breast like a mammogram.

Inclusion Criteria:

• For the screening cohort, the inclusion criteria are, women: (1) who were 40 years of age or older (typical screening age range), and, (2) who were asymptomatic, and, (2) who underwent or scheduled to undergo a standard-of-care 2-view bilateral digital breast tomosynthesis screening exam.

For the diagnostic cohort, the inclusion criteria are, women: (1) who were 40 years of age or older, and, (2) who underwent a standard-of-care 2-view bilateral digital breast tomosynthesis exam, and, (3) who were assigned BI-RADS category 4 or 5 after diagnostic work-up and are scheduled for biopsy.

Exclusion Criteria:

• Males; women less than 40 years old; pregnant or lactating women; women with physical limitations (e.g., kyphosis) that may prohibit UBCT exam; women who have received radiation treatments to the thorax; women who have participated in a prior breast clinical trial that gave additional radiation dose; and, women who have received large numbers of diagnostic x-ray examinations for monitoring of disease such as tuberculosis, and severe scoliosis.

Only women, aged 40 years or older, who are eligible for mammography screening are eligible to participate.

IPD information may be shared with individual academic investigators in accordance with the University of Arizona's data sharing agreement.