Samarium-153 (Sm-153) is a radionuclide that decays with physical half-life 46.3 hours through the emission of beta and gamma radiation. The beta energies are particularly suited for targeted radionuclide therapy, whereas the low energy gamma radiation is well suited for diagnostic imaging. In the last two decades, Sm-153 has been used as both a radiotracer for pharmacoscintigraphic studies and a therapeutic radionuclide for the treatment of bone metastasis. This book presents a study investigating the use of Sm-153 as a tracer for imaging in oral drug delivery and clinical diagnostics of gastrointestinal transit. The production, physical and imaging characteristics, in vitro experimental validation, clinical trial as well as radiation dosimetry of novel Sm-153 labelled formulations are explained in meticulous detail. Work from each of these chapters has been published in academic journals and international conferences and has received several awards. This book provides a complete compilation of the entire work.