Development of a Quantitative Tissue Optical Index of Breast Density For Prediction of Hormone Therapy Response

The purpose of this research study is to investigate whether breast density measured by a safe, painless imaging method (called Diffuse Optical Spectroscopic Imaging - DOSI) can detect the decrease of breast density in subjects who receive tamoxifen when compared to patients who do not receive any drug. If decreased density can be reliably detected, it may help determine which subjects will benefit by taking tamoxifen or other chemoprevention drugs.