Radionuclides in orthopaedic surgery.

Bone scanning with radioactive isotopes has become a routine method for investigating disorders of bone. Departments of nuclear medicine throughout the country offer diagnostic facilities for a variety of problems which affect not only bone, but also the heart, kidney, brain, liver, pancreas and spleen as well as disorders of the blood. Indeed the use of radionuclides is now an important and established part of investigative medicine. It is the purpose of this article to present the role of radionuclides in orthopaedic diagnosis. For a long time the essential confirmatory diagnostic method in orthopaedic practice has been the use of radiographs which demonstrate clearly the pathology in the bone but in two dimensions. What troubles many orthopaedic surgeons is the ability to note the state of the bone and not to be able to detect the period the bone has been affected. In other words, is the increased density noted in the radiographs of the hip in Perthes’ disease the end of the disease when the bone has healed and revascularised, or is it a stage when the bone is actually being destroyed? To help clarify the situation bone scanning with radionuclides has been introduced. By looking at bone in a three-dimensional way, whole new fields of bone turnover and mineral distribution have been explored. It is now possible to look at bone and study what is actually happening at the moment of the bone scan. However, in order to interpret the scan it is vital to understand the mechanism of bone scanning.