Ultrasound Machine

An ultrasound machine is medical equipment that uses sound waves above the range of human hearing for diagnosis and, in some uses, therapy, producing images by sending pulses into the body and reading their echoes, a process called echography. A piezoelectric transducer in the machine's probe emits sound pulses at frequencies of roughly 1 to 18 megahertz; when these waves meet tissues of different density they partly reflect back as echoes, and the machine measures the timing and strength of each echo to build a two-dimensional grayscale image of the tissue's depth and structure. Obstetrical ultrasound, one of the first major clinical uses, was pioneered in the late 1950s and 1960s by Ian Donald, and the technology has since spread across medical specialties, from examining the heart to monitoring a fetus.