This book is based on contributions presented at the 1st World Congress on Gallium-68 and Peptide Receptor Radionuclide Therapy, which examined recent developments in theranostics - the emerging field of molecular targeting of vectors that can be used for both diagnosis and therapy, when modified accordingly. The focus of this book is on the rapidly developing research into and clinical applications of gallium-68 and other generator-produced PET radionuclides in the personalized diagnosis and treatment of neuroendocrine tumors and other diseases. In addition, new PET radiopharmaceuticals are considered, and the latest ideas and concepts, presented. Theranostics embodies both molecular and personalized medicine. It is at the cutting edge of medicine, and the contents of this volume will be of interest to chemists, physicians, and investigators dealing with generators, PET radiochemistry, molecular imaging, and radionuclide therapy.