Engineers have crafted the world’s highest-frequency circuit made with a common type of semiconductor transistor, a step that could slash the price of detectors useful in earlier cancer detection and quicker pollution spotting. Ultra-high-frequency circuits have been created in the past, but only with exotic materials that are costly to manufacture. CMOS, by contrast, is the standard process used to make the majority of the circuits in the integrated circuit industry. That opens the door to widespread manufacture and distribution of the high-frequency circuits. At a recent conference, the scientists demonstrated a 410-gigahertz circuit using complementary metal oxide silicon, or CMOS, technology — the technology used to make many of the components in personal computers, cell phones and handheld electronic devices.