According to NIH definition of clinical trial studies, this study does not meet requirement for clinical trial study.

Approximately twelve percent of the women in the United States will develop breast cancer, the most common form of cancer affecting women, with 183,000 new cases projected for 1995. Despite the increasing incidence, the age-adjusted death rate from carcinoma has remained relatively stable. Although the reason for this has not yet been demonstrated, this stability may be a direct consequence of early detection and improved therapy. Screening mammography as an early detection technique has been shown to reduce mortality by 23%. Mammographic abnormalities that go on to biopsy show 24% being positive for malignancy with great variability (6-75%). Breast biopsy is an expensive procedure with the risks of anesthesia and surgery which may be obviated by more specific non-invasive testing.

Diffuse Optical Spectroscopic Imaging a new method for quantitative characterization of the optical properties of tissues. The diagnostic tools utilize anomalies in the transmission of diffusing near infra-red light for the rapid detection of oxygenated and deoxygenated hemoglobin, near infra-red absorbing drug levels, blood volume changes, and scattering properties in tissues.

Diffuse Optical Spectroscopic Imaging measurements of breast tissue optical properties probe is similar in shape to an ultrasound probe. The imaging can measurements on different areas of the breast including diseased location and normal area. Optical measurements can guided by co-registered ultrasound measurements for the purpose of determining lesion size and location. Each measurement will require about 5-60 seconds to record the data and calculate optical properties. The process will be repeated until an adequate number of measurements are performed and measurements take 30 to 90 minutes.

The researcher can determine that breast optical properties on demographic information, such as age and menopausal status as well as medical history.

Inclusion Criteria:

• Non-pregnant woman age 18 yrs and older.

Exclusion Criteria:

• pregnant woman and younger than 18 yrs of age.

Study population will be selected from University of California Irvine Medical Clinic and Cancer Center.