A combined molecular breast imaging / ultrasound system will enable coregistration of a functional abnormality seen on Molecular Breast Imaging (MBI) with the corresponding anatomical abnormality seen on ultrasound.

Inclusion Criteria:

• The pilot study will comprise 12 women age 40 and older who have at least one of the following inclusion criteria:

  1. Have a finding of a mass lesion on mammography or breast MRI (BIRADS 0, 4 or 5) that is >0.5 cm and < 2 cm in size and has had or will have additional workup with focused ultrasound.
  2. Have a finding of a mass lesion on ultrasound (BIRADS 0, 4 or 5) that is > 0.5 cm and < 2 cm in size.
  3. Have a positive finding on MBI that is < 2 cm in size and requires additional diagnostic workup with focused ultrasound.

Exclusion Criteria:

1. Are unable to understand and sign the consent form
2. Are pregnant or lactating
3. Are physically unable to sit upright and still for 40 minutes
4. Have undergone bilateral mastectomy
5. Are not scheduled to undergo conventional ultrasound