Stereotactic core needle biopsy is a minimally invasive procedure for the diagnosis of a nonpalpabral breast lesion. Although ultrasound-guided needle biopsies are less expensive (or 'cost effective', in weasel talk), they are more operator dependent, with an accuracy between forty-seven and ninety percent.

Stereotactic core biopsies requires an incision only four millimeters in size, with a more reassuring accuracy of ninety-eight percent. However, the SCNB has some drawbacks. When atypical ductal hyperplasia is the diagnosis, a woman is required to have an excisional biopsy done. About one out of three patients require a second diagnosis after a stereotactic core needle biopsy. About two in five patients who had second diagnostic procedures done after the SCNB were found to have cancer.

Now, the part you really want to know. How they do it. The patient is positioned on a table, providing three hundred sixty degree access. The breast is compressed. Stereotactic x-rays are then taken for targeting within one millimeter of the lesion. A localizing needle is guided to the precise location of the lesion by the digital stereotactic x-ray through and incision. When the needle is in place and verified, a T-fastener is then deployed, fixing the lesion in place. The position is again verified. The biopsy begins with further infiltration of a local anesthesia and an extension of the cut. If the lesion is located deep in the tissue of the breast, the superficial tissues are moved by a scapula. A cyndrilical cannula is pushed over the needle while a motorized circular blade cuts the tissue. It is pushed to the depth of the tumor and it's location verified and the tumor has been captured by the cannula. A cautery snare cuts across the deep end of the cannula, and the sample can be removed. A complete mammogram is taken before the patient is taken out of compression. A x-ray confirms that the malignant tissue was removed. Then, the patient is rolled into a supine position for inspection of the biopsy site. Bleeding is common and easily controlled by cautery, clips, or sutures. There are four cannula sizes available: five, ten, fifteen and twenty millimeters.