ThermoTrex Corp. in San Diego received $3.7 million as part of a three-year, $15 million contract from the Ballistic Missile Defense Organization to develop active-pixel image sensors. The patented complementary metal oxide semiconductor (CMOS) technology has been under development for the last few years as part of the company's research into a full-field digital mammography system. CMOS image sensors offer several advantages over traditional charge-coupled device sensors, including lower manufacturing costs and smaller size.