Abstract: A planar template and measuring device is provided for guiding a biopsy needle to a predetermined point with angular and radial coordinates, in a cross-sectional plane of a patient's torso, derived from CT scans of the patient. The device is configured to fit across and around the torso of a patient lying on the table of a CT scanner, when the device is positioned at right angles to the plane of the table and the long axis of the patient. The template is slidably mounted on rails attached to the long sides of the table so that it can be positioned at any point on the long axis of the patient. The device has an arcuate slot defining a part-circle marked with an angular scale, the center of which coincides with a central reference point of the CT scanner. A sliding carriage for a biopsy needle travels along the slot and may be set at any desired angle relative to the part-circle.