The needle localization may be performed either under ultrasound guidance or mammographic guidance, depending on which type of imaging best shows the abnormality. The breast is cleaned with antiseptic and is anesthetized with local anesthetic. A small needle is placed into the breast in the area of abnormality. After the radiologist is certain that the needle is in exactly the right position, a thin wire is placed through the needle and the needle is removed. All that is left in the breast is a thin wire marking the area of abnormality. Mammographic pictures are then taken and sent with the patient to the Operating Room. There is usually only slight discomfort, if any, during this procedure.