Abstract: The present invention pertains to a fiducial implant for the human body that is detectable by an imaging system. The invention is comprised of a first portion and a second portion. The first portion is configured to be detected by an imaging system when place beneath the skin. The second portion is configured for fixed attachment to a bone beneath the skin without penetrating entirely through the bone and without penetrating entirely through the bone and without fracturing the bone. The first portion is sufficiently large and comprised of a material for detection by an imaging system, and sufficiently small to avoid the distortion of the skin when placed at an interface between the skin and the bone. The first portion also has at least a portion which is spherical and defines a surface for cooperating with a tool for securing the second portion to the bone. Additionally, the placement of n fiducial implants, where n.gtoreq.