This proposal is a request for a Packard InstantImager Electronic Autoradiography System which electronically locates and measures radioactivity directly on gels, blots, thin layer chromatography, tissue slices, or any other flat samples up to 20 X 24 cm2. This instrument will directly measure in real time disintegrations eliminating the need for either X-ray film or storage phosphor screens. The Boston University biochemistry department is a large multifaceted teaching and research department. Most members perform basic research in molecular and/or cellular biochemistry. Usually this research requires radiolabeling techniques in order to detect small amounts of biologically relevant molecules. Radiolabeled proteins, RNA, DNA and lipids are often separated by gel electrophoresis or thin layer chromatography and visualized by autoradiography using X-ray film. X-ray film autoradiography has distinct disadvantages such as low sensitivity and small linear range making quantitative analysis difficult and laborious. Typically, samples need to be exposed overnight or longer. Often multiple exposures are necessary in order to detect both high and low abundant molecules on the same gel. Most researchers, when quantitation is critical, remove radiolabeled material from solid supports in order to measure disintegration using a scintillation counter after visualization by X-ray film. Recent advances in technology are making alternate instruments available to locate and directly measure radioactivity on flat samples with more sensitivity in far less time. The instrument will help research efforts and will be used in several courses as an instrument to teach essentials regarding radioactivity measurements.