A 3D mammogram can:

Help diagnose common breast issues: 
A 3D mammogram can help identify breast health problems such as lumps or masses, and help point to the cause of other problems such as pain and nipple discharge.

Improve the detection of breast cancer in breast tissue:
The supportive breast tissue (also known as the dense breast tissue) and breast cancers will both look whitish on a standard mammogram. This can make it difficult to locate and diagnose breast cancers.  A 3D mammogram allows your doctor to see past the dense areas and can increase the detection of breast cancer.

Detect more cancerous tissue than a standard mammogram: 
Research shows that a 3D mammogram slightly increases the rate of cancer detection compared to a standard mammogram.