An x-ray of the breast; the method of finding breast cancer that can’t be felt. Mammograms are done with a special type of x-ray machine used only for this purpose. A mammogram can show a developing breast tumor before it is large enough to be felt by a woman or even a highly skilled health care professional. Screening Mammography is used to help find breast cancers early in women without any symptoms. Diagnostic Mammography helps the doctor learn more about breast masses or the cause of other breast symptoms.