An apparatus for a securing a magnification marker to a subject such as a human patient includes an elongated strap that has a length sufficient for surrounding the subject around a region, such as a knee or pelvis, that is to be radiographed. A radiopaque magnification marker of a predetermined size is carried by the strap. Fasteners are included for fastening the strap to itself with the strap in a fastened configuration surrounding the subject, thereby to secure the strap to the subject with the magnification marker adjacent to the region to be radiographed. In one embodiment, the strap is stretchable and configured to allow the fastened strap to slide along the subject to adjust the position of the magnification marker relative to the region.
