With the patient lying on her back or turned slightly to the side, the ultrasound probe is used to locate the lesion. Enough local anesthesia is injected to be sure that she will feel no discomfort during the procedure. Ultrasound is also used to guide the injection of an anesthetic along the route to the lesion and about the mass. A very small nick is made in the skin at the site where the biopsy needle is to be inserted. The radiologist, constantly monitoring the lesion site with the ultrasound probe, guides a hollow core biopsy needle or the vacuum-assisted needle directly into the mass and obtains specimens. Usually at least four samples are taken. In some cases it may be difficult to visualize the needle in the breast tissue and considerable skill is needed to coordinate movements of the ultrasound transducer with needle insertion. If the lesion is nearly or completely removed during the biopsy procedure, a clip is placed where the lesion was located to ensure that the site can be easily located for additional surgery if the lesion proves to be malignant.

You will be awake during your biopsy and should have little or no discomfort. Generally the biopsy is completed in less than an hour. It is not necessary to close the tiny skin incision with sutures; a small compression dressing will do. Most patients are able to resume their usual activities later the same day.