Abstract: The early-screening and diagnosis of breast cancer is very important for improving the life quality of women as well decreasing the death rate. As a main diagnostic technique, mammography might cause radiation damage to the human body. Near infrared (NIR) computer diaphanography imaging diagnosis (CDI) is a new technique for breast cancer diagnosis which can be performed multiple times with no harm. However, its high incidence of false positivity has raised doubts and questions. We introduce the physical principles of CDI, and discuss the mechanism of how a malignant growth surrounds itself with a dense network of tiny blood-filled capillaries to feed oxygen and nutrients to active tumors, thus forming unique NIR transmittance markers that reveal the presence of cancer. The advantages and difficulties of CDI are evaluated, with the conclusion that CDI satisfies all the “three-conditions” of imaging diagnosis. The influence of competition with mammography in the development of CDI is reviewed. The opportunities of physics interacting with the life sciences are outlined.