A system for determining the position and orientation of a medical device relative to an image space during image-guided medical procedures. The system comprises a flexible pad mounted on the subject such that a part covers the region of interest. The pad incorporates detectable registration members. Prior to the procedure, the device is coupled to the pad, which is then rigidized, so that there is no movement of the registration members relative to each other and relative to the device. The fixed relation- ship between the device and the registration members is determined from initial images, for example using detectable markers attached to the device, enabling the pose of the device relative to the image space of images of the region of interest to be determined later, even if the device is remote from the region of interest. This minimizes exposure of the subject and medical staff to radiation.
