This is the fourth in our biennial series aimed at helping practicing medical physicists, technically-inclined physicians, and other interested professionals stay current in medical radiation science and technology. This volume covers 20 new and important topics in diagnostic imaging and radiation therapy. Recent developments in fluoroscopic imaging systems for interventional procedures are described by Barry Belanger, while Beth Schueler and Kenneth Fetterly update us on the latest in fluoroscopy acceptance testing and quality control. CT is also front and center in this volume as Thomas Flohr and Bernhard Schmidt describe the latest advances in CT; James Kofler describes the trade-offs among speed, resolution, and dose from various CT scan acquisition settings; and Robert Dixon and others cover new dosimetric concepts and measurement methods in CT.