The Stereotactic Needle Biopsy Training Phantom is a disposable training tool and practice medium for mammographic needle biopsy procedures. The phantom also serves as an excellent quality assurance device for stereotactic systems and should be used whenever a new system is installed or repaired to ensure accurate needle placement. The phantom can be used to perform the localization accuracy test in the American College of Radiology's stereotactic breast biopsy accreditation program. The phantom body is shaped to represent a partially compressed breast. This allows the user to easily compress the breast to 4.5cm thickness for optimum imaging. The shape also enables the phantom to be used in systems where the patient is either prone or sitting. The phantom is made from a proprietary gel with a physical consistency similar to human tissue and, since the gel is a non-flowing material, it won't leak out when punctured.