Back in the 1940’s the ultrasound was considered therapeutic due to the thermal energy it was generating. It was used for arthritic pain, asthma, gastric ulcers, eczema, angina pectoris and urinary incontinence.

The first use of ultrasound as a diagnostic tool dates back to 1942 when a neurologist from the University of Vienna, Karl Dussik tried to locate brain tumours and cerebral ventricles by measuring the transmission of ultrasound beam through the skull.

Systematic use of ultrasound for diagnostic purposes started with George Ludwig diagnosing gallstones in 1948.

The late 1960s and early 1970s were referred to as the sonic boom, when the two-dimensional (2D) echo was introduced by Klaus Bom. In 1966, the pulsed Doppler technology was developed by Don Baker, Dennis Watkins, and John Reid, which enabled the detection of blood flow in the heart. Don Baker was also involved in developing the colour Doppler and duplex scanning. In 1980s the real-time ultrasound started to appear and in the 1990s, the scientists have progressed with developing the 3D and 4D images.