This Annals volume aims to encompass the latest trends and developments of PET/CT imaging in non-neoplastic disease along with its application in clinical decision-making. The topics included are intended to be helpful to internal medicine specialists and subspecialists, as well as neurologists, psychiatrists, general radiologists and Nuclear Medicine physicians. For example, PET myocardial perfusion imaging provides an accurate and non-invasive means in the evaluation of ischemia and the assessment of myocardial viability as well as the potential for myocardial blood flow quantification. In addition, PET imaging aids in the early diagnosis and timely intervention in potentially devastating dementias. Finally, the utility of PET imaging in a variety of inflammatory diseases such as lupus and myositis continues to evolve and appears promising in yielding an accurate and timely diagnosis.