New developments in the field of high resolution imaging focus on functional parameters pertaining to disease-specific medical imaging. Such new diagnostic strategies are possible using scintigraphic techniques and, more recently, by MRI and US. In addition, new therapeutic concepts, including gene therapy, require specific tracers or contrast media for therapy monitoring, for example, enzyme activity and changes in receptor expression. For this purpose scientists conducting basic research, expecially molecular biologists, and clinicians must collaborate in order to exploit the available interdisciplinary knowledge in the development of new imaging technologies so as to incorporate the molecular signals of diseases. Diagnostic imaging relies primarily on morphological criteria. However, there is an incereasing need for more disease-spcific informatin. New developments in imaging techniques and in molecular biology provide new imaging strategies to address functional and disease-specific parameters for clinical and scientific applications. The acquisition of functional and disease-specific information may lead to true "molecular imaging" which benefits from intensive collaboration between biologists, clinicians and physicists. This workshop formed the platform for an intensive discussion between experts in the fields of molecular biology and diagnostic imaging on basic principles, current methodology and future perspectives of MR, ultrasound and scintigraphic imaging approaches. This book is a comprehensive summary of the presentations and sicussions of the workshop. It provides the reader with the state-of-the-art informationi on diagnostic imaging and the links to molecular biology that are necessary for the development of molecular imaging.