This book explores the close connection between immunology and nuclear medicine, which has led to radioimmunoimaging and radioimmunotherapy (RIT). Molecular imaging with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) is increasingly being used to diagnose, characterize, and monitor disease activity in the context of inflammatory disorders of known and unknown etiology, such as sarcoidosis, atherosclerosis, vasculitis, inflammatory bowel disease, rheumatoid arthritis, and degenerative joint disease. The first chapters discuss the various radiopharmaceutical agents and radiolabeled preparations that have been employed in inflammation imaging. Of these, FDG-PET imaging has been shown to have the great value in the detection of inflammation and has become the centerpiece of several initiatives over the last several years.