A device intended to be implanted within the body, either temporarily or permanently, to create identifying marks that can be seen on radiographic film or digital images. It is typically in the form of a wire, needle, bead, clip, stent-like tube, washer or fluid, and used to locate and delineate a tumour, lesion, or other site of interest. It is made from materials compatible with the imaging system with which it is intended to be used [e.g., magnetic resonance imaging (MRI), x-ray, or nuclear medicine]; it may be intended for use during radiotherapy procedures.