DESCRIPTION CONTINUED:  The second phase of the project is using computers to detect breast cancer by mimicking the well-developed protocols followed by radiologists.  For example, it is difficult to detect a breast cancer sign in an individual mammogram.  It becomes easier to do so by examining the series of mammograms over time in the same subject because the changes which take place in the breast contrast with a growing cancer, i.e. the parenchyma is replaced by fat which is translucent, whereas the cancer grows and stands out.  Similarly, another part of the radiologist technique is to compare both breasts because they are roughly symmetric.  Any asymmetries between the two are indicative of the presence of cancer. 
