Diphosphonate bone scanning agents--current concepts.

The bone scan is generally recognized to be an extremely powerful investigational tool in the evaluation of patients with skeletal disease. Currently 99mTc-methylene diphosphonate is the most widely used bone scanning agent, but recently several new diphosphonate compounds have been introduced which appear to have relatively higher skeletal affinity, leading to greater absolute uptake of tracer by bone. While the resulting improved contrast between bone and background soft-tissue may provide more pleasing scan images, it is not clear that increased bone uptake of tracer is equally desirable for identification of disease. Nevertheless, to date, no significant difference in lesion detection has been found in any comparative study of diphosphonate compounds. In this review the clinical studies evaluating diphosphonate bone scanning agents are summarized and the properties required of an ideal bone scanning agent in both benign and malignant disease discussed.