CMOS Cassette For Digital Upgrade of Film Based Mammography Systems

DESCRIPTION (provided by applicant): While full-field digital mammography (FFDM) technology is gaining clinical acceptance, the overwhelming majority (96%) of the installed base of mammography systems are conventional film-screen systems. A high performance, and economical digital cassette-based product to conveniently upgrade screen-film mammography systems to FFDM would accelerate the adoption of FFDM, and make the clinical and technical advantages of FFDM available to a larger population of women. To this end, in the first phase of this research, we are going to develop a prototype full-field digital mammography (FFDM) cassette, designed in the exact form factor of a standard 18 cm x 24 cm mammography film cassette. In subsequent phases of this research, we will implement the same technology in the form factor of a standard 24 cm x 30 cm cassette. The proposed FFDM cassette will be based on our current commercial digital cassette product for 10 cm x 10 cm field-of-view, quasi real-time digital breast specimen radiography, utilizing 150 micron columnar Csl(TI) scintillator deposited on high performance, high resolution, 48 micron pixel, custom designed, active-pixel CMOS sensor modules. Unlike a Computed Radiography (CR) cassette, which requires an external digitizer, our proposed Digital Radiography (DR) cassette will transfer acquired image data to a display workstation via a fiber optic data cable within approximately 7 seconds of x-ray exposure, greatly enhancing patient flow in screening mammography. In Phase I, we will evaluate the physical performance of the prototype system against other FFDM system in clinical use today, using established objective criteria such as the Modulation Transfer Function (MTF), Noise Power Spectrum (NPS), and Detective Quantum Efficiency (DQE), and subjective criteria, such as a contrast-detail observer performance study. Utilized in large quantities in the fabrication of integrated circuit (1C) chips for the computer industry, CMOS technology is one of the lowest cost, and most readily accessible technologies available for FFDM today. Recent widespread application of CMOS sensors in consumer digital cameras have also resulted in significant advances in the imaging performance of CMOS sensors, with sensitivity and noise characteristics now rivaling CCDs. This project proposes to take advantage of these unique features of CMOS technology to develop the first FFDM upgrade cassette of its kind.