Abstract
Radionuclide bone scanning (RNBS) using technetium-99m-labelled diphosphonates (MDP) is a frequently performed technique in nuclear medicine. It is widely regarded as the most cost-effective and widely available whole-body screening test for the assessment of bone metastases and other focal bone lesions. The technique is often combined with conventional radiography to improve the diagnostic accuracy. <br><br> Recently, this role has been challenged by newer imaging modalities such as CT, MRI and PET-CT. These techniques have limited worldwide availability, are expensive and have their own limitations but can complement RNBS. For example, CT scanning is useful in guiding needle biopsy, particularly in vertebral lesions. MRI is helpful in determining the extent of local disease in planning surgery or radiation therapy. <br><br> RNBS, although non-specific, has an excellent sensitivity, which makes it a useful tool for characterizing some conditions that are not clearly depicted on anatomic images. Bone metastases generally appear as multiple 'hot' lesions, although occasionallythey may be 'cold'.