METHOD AND APPARATUS FOR CALIBRATING A BIOPSY ATTACHMENT FOR ULTRASONIC IMAGING APPARTUS

A sector-scan ultrasonic imaging apparatus includes a biopsy attachment mounted on the housing of the imaging apparatus for positioning a biopsy needle relative to the ultrasonic scan head of the imaging apparatus. An image display device displays both an image of the region scanned by the scan head and a predetermined, superimposed electronic representation of the position of the biopsy needle-line relative to the probe scan head. The biopsy needle-line is calibrated with a scan head coordinate system which defines a sector sweep of the scan head by determining the coordinates of the needle-line in the scan head coordinate system independently of determining the particular spatial relationship of the needle-line in operative position relative to the scan head. A calibration member adapted to be mounted on the biopsy attachment includes at least two ultrasonic reflection regions which are scanned by the scan head during the calibration mode and displayed on an image display device. The display of these at least two reflection regions enables the needle-line coordinates to be determined using the predetermined geometric relationship of the calibration member with respect to the imaging apparatus housing. Alternatively, the calibration member can include a single ultrasonic reflection region, and an angular detector can be used to determine the angular orientation of the calibration member relative to the probe scan head, to enable the needle-line coordinates to be determined.