1 Introduction Christian Schiepers went major revisions. A few were updated and had CONTENTS only minor revisions (Chaps. 4, 7 and 15,) and two 1. 1 Perspective 1 were left unchanged and re-printed from the first 1. 2 Objectives 2 edition. Our selection is aimed at elucidating key 1. 3 Clinical Overview 2 processes in cellular mechanisms of the human body, 1. 4 Basics of Diagnostic Nuclear Medicine 4 under normal conditions as well as in disease. 1. 5 Future Perspective 4 In the present revised volume of Diagnostic Nuclear 1. 1 Medicine, the advancements in the field of nuclear Perspective medicine (NM) are presented with an emphasis on progress in the beginning of this millennium. The NM started as a field where radioactive products name ‘molecular imaging’ is used more frequently were put to use for the benefit of mankind, e. g. t- for diagnostic NM imaging, but is not commonplace. roid scintigraphy and therapy. The performed stud- We will use the traditional term NM. The various ies in the field have fluctuated tremendously since contributions in this imaging field such as new trac- those early years. Flow imaging of the brain was a ers and equipment, modifications of existing tests, frequent procedure in the NM clinic until CT was diagnostic algorithms, and general applications for introduced. Later on, sophisticated triggering te- whole body imaging are discussed.