An apparatus for use with an image-guided system to calibrate a handpiece having a tip that is difficult to calibrate comprises a tip extension having an attachment end and a round end, the attachment end configured to fixedly attach to the tip of the handpiece. The attachment end may include a female component that mates with a correspondingly shaped male component of the tip of the handpiece. The tip extension may have a neck configured to allow rotation of the round end when the round end is in a round recess. A method of using an image-guided system to calibrate a handpiece having a tip may comprise fixedly attaching to the tip an attachment end of a tip extension, the tip extension also having a round end separate from the attachment end； and calibrating a center of the round end by contacting the round end to a calibration device.
