This book is a guide to new and emerging PET technology, instrumentation, and its place in clinical practice. PET technology is currently moving from the conventional photomultiplier tube (PMT) detector based PET to the new generation, solid state light sensor detector. This is a technological leap and holds significant implications for the use of PET imaging. This book introduces and describes the emerging and new generation of PET instrumentations and technologies across manufactures, focusing on solid-state PET detector designs, system characteristics, and clinical practices as well as future advanced Time-of-Flight (TOF) PET technologies.