Scientists have been fascinated by the mechanisms of acoustics, echoes and sound waves for many centuries. Numerous famous individuals, including Aristotle, Leonardo da Vinci, Galileo Galilei, Sir Isaac Newton and Leonard Euler studied these phenomena. However, it was not until 1877 that Lord Rayleigh published a description of sound as a mathematical equation in “The Theory of Sound”. A few years later Jacques and Pierre Curie discovered the piezo-electric effect, that is, an electric potential is generated when mechanical pressure is applied to a quartz crystal. (Interestingly, these findings date several years before the discovery of X-rays bConrad Roentgen 1895. ()
Around 1900, with the invention of the Diode and Triode, powerful electronic amplification became possible, leading to the development of a high frequency ultrasonic device by scientists Langévin and Chilowsky.)This machine, called ‘hydrophone’, sent and received ultrasonic signals underwater. The Titanic disaster in 1912 and World War I accelerated investigations of underwater and airborne echo- ranging systems and antisubmarine warfare research, which lead to the beginning of SONAR (Sound Navigation and Ranging) and RADAR (Radio Detection and Ranging, using electromagnetic waves). The main industrial application of ultrasonic waves in the 1930’s and 1940’s became the detection of metal flaws.
The first application of ultrasound as a medical diagnostic tool was published in 1942 by Karl and Friederich Dussik in Vienna. The Austrian brothers attempted to locate brain tumors and the cerebral ventricles by measuring ultrasound transmission through the skull. They concluded that if imaging of the ventricles was possible, the interior of the human body could also be visualized using ultrasound. This marked the beginning of diagnostic ultrasonography in the medical field
