The objective of the proposed research is to construct a prototype narrow-bandwidth x-ray source for medical imaging using a compact betatron and a parametric x-radiator (PXR). The device will resemble a "table-top synchrotron" in that it uses a recirculated electron beam to produce intense collimated quasimonochromatic x rays. Such a source will provide higher quality radiograph images while lowering the dose to the patient. The research will proceed by completing the design of the betatron/PXR source using available betatron technology. The compact source will then be assembled and quasimonochromatic x rays generated. Methods to further increase the brightness of the source will be explored experimentally. Finally, images of inanimate phantoms will be used to quantify the imaging system's characteristics. The PXR images will also be compared with those taken from a conventional mammography unit. The potential for successful development of the prototype imaging system is very high because our phase I research has experimentally demonstrated both electron recycling and narrow-bandwidth PXR generation. These results indicate that a high quality mammogram can be generated in less than 3 seconds. PROPOSED COMMERCIAL APPLICATION: A compact, inexpensive x-ray source with characteristics similar to the synchrotron has benefits of making high x-ray fluxes more accessible. The natural collimation of PXR permits reduced scattering while the narrow bandwidth and frequency selection optimizes contrast and reduces dose.