Direct Digital Mammography Using Capillary Optics

Abstract

Abstract : The overall objective of this proposal is to develop a mammographic system with extremely high scatter rejection and dynamic range, good resolution and low patient dose. This will be accomplished by developing a direct x-ray detector interfaced with a capillary x-ray optic. Capillary x-ray optics, invented in the mid-eighties, provide an innovative new way to control x-ray beams. A number of promising geometries are being studied: collimating optics with long and short focal lengths, with and without antiscatter optics, monolithic linear magnifying tapers, and monolithic focusing, demagnifying optics. The collimating optics have transmissions in excess of 30% at their design energies, with collection angles ranging from 8 to 12 degrees. Scatter rejection is very high from all the optics. The linear tapers resulted in nearly ideal contrast enhancements and simultaneously increase in MTF at all spatial frequencies. The rapidly growing modeling capability is already leading to improvements in the manufacturing processes. Direct digital detectors owe their high efficiency and resolution to the direct detection of x-ray photons without requiring phosphors for the conversion to visible light. One dimensional imaging was demonstrated with the CZT linear array. CID two-dimensional arrays with small pixel sizes are another promising new technology for mammography.