A mammogram is a breast X-ray that uses low doses of radiation to detect cancers early for better prognosis (outcome). Mammography can be used either to look for very early breast changes without symptoms (screening) or to examine women who have breast symptoms (diagnostic). Most of the time these symptoms turn out to be benign (non cancerous) or a cyst (fluid filled sac).
You will need to undress from the waist up. One of your breasts will be positioned between two plastic plates which will flatten the breast slightly. Most women find that this is a bit uncomfortable, but not painful. Generally two x-rays are taken of each breast. It is also useful to compare the results with earlier examinations and you should take any previous mammography results with you.