Work carried out on the development of instrumentation and techniques for positron scintigraphy is discussed. Progress in positron imaging instrumentation and applications is detailed. The assembly and initial evaluation of the new multicrystal positron camera, PC-II, has been completed. Images have been obtained in both two and three-dimensions which demonstrate the basic physical properties of the instrument. Successful measurements using transverse section imaging have been carried out on animals and human volunteers. Physiological investigation using PC-II is proceeding. A flexible and accurate computer program has been developed for transverse section reconstruction of data acquired by PC-II. This program makes it possible to reconstruct both the activity distribution and the distribution of absorption. The program has been developed in such a way that it can handle variations in the data collection procedure. Clinical studies using PC-I and PC-II are being carried on in areas of heart, lung and brain.