Tomosynthesis is a new digital mammographic tool which can be performed at the same time as routine screening mammography. It creates CT-like slices through the breast, minimizing the tissue overlap. Tomosynthesis has the potential to improve screening mammography outcomes by increasing cancer detection rates, decreasing false negative rates and false positive rates. This trial will help determine if tomosynthesis is useful in a screening setting.

We will evaluate the effect of tomosynthesis mammography outcomes in a screening setting. We will collect data on interpretation time, recall rates, cancer detection rates, and interval cancer rates in dense breasts(≥ 50% glandular density). If the interpretation time is less than 4X a routine read, and the recall rates have dropped < 30% of initial values, we will then conduct a study with larger numbers to better evaluate cancer detection rates and interval cancer rates.

Inclusion Criteria:

• Females 40-69 years of age attending Screen Test Kingsway referred for a screening mammogram as defined by Canadian Cancer Society guidelines.
• Prior mammogram report indicating ≥ 25% breast density.

Exclusion Criteria:

• Prior mammogram report indicating <25% breast density.
• Breast implants
• Pregnancy