**15. Conclusion**

Nuclear medicine techniques supply physiological information that is complementary to that provided by radiological techniques and can play a fundamental role not only for the examination and treatment of articular disorders but also in overall patient evaluation.

Though scintigraphical examination is ideal in the early stages of diseases, it also plays a complementary role to radiographical investigations in more advanced disease stages. An assessment as complete as possible which includes different complementary studies must be performed to achieve the best diagnostic and prognostic accuracy. In this context, conventional scintigraphy is still a major test in a limited number of rheumatological diseases such as Paget, reflex sympathetic dystrophy and osteonecrosis, and can be a useful complementary study in other diseases. New molecular imaging tools for the evaluation of musculoskeletal diseases are now available and these particular tools will advance the understanding and management of several chronic musculoskeletal diseases. In the next decade, PET/CT and SPECT/CT will be the major workhorses for molecular imaging, with the advantage that PET-based technologies have high sensitivity and the ability to use biologic molecules that can be radiolabelled.

Despite the important role of the anatomic imaging techniques in the evaluation of primary bone tumors and metastases, radionuclide imaging techniques have all been used in the assessment of these disorders. PET and hybrid PET/CT imaging are becoming the most important modalities in this field.

Β-radiation emission from some radionuclides has been exploited by nuclear medicine and has been used to treat benign joint pathologies, as well as treating several forms of neoplasia. It is of interest in the field of rheumatology, since it is as a safe procedure and, after intra-articular administration of suitable radiopharmaceuticals, is able to control proliferation of the inflamed synovial membrane in the treatment of chronic arthropathies, particularly in the initial stages of the disease.
