• Increase font size
  • Default font size
  • Decrease font size

Z historii ultrasonografii

A short History of the development of Ultrasound in Obstetrics and Gynecology

Dr. Joseph Woo

he story of the development of ultrasound applications in medicine should probably start with the history of measuring distance under water using sound waves. The term SONAR refers to Sound Navigation and Ranging. Ultrasound scanners can be regarded as a form of 'medical' Sonar.

As early as 1826, Jean-Daniel Colladon, a Swiss physicist, had successfully used an underwater bell to determine the speed of sound in the waters of Lake Geneva. In the later part of the 1800s, physicists were working towards defining the fundamental physics of sound vibrations (waves), transmission, propagation and refraction. One of them was Lord Rayleigh in England whose famous treatise "the Theory of Sound" published in 1877 first described sound wave as a mathematical equation, forming the basis of future practical work in acoustics.  As for high frequency 'ultrasound', Lazzaro Spallanzani, an Italian biologist, could be credited for it's discovery when he demonstrated in 1794 the ability of bats navigating accurately in the dark was through echo reflection from high frequency inaudible sound. Very high frequency sound waves above the limit of human hearing were generated by English scientist Francis Galton in 1876, through his invention, the Galton whistle.

The real breakthrough in the evolution of high frequency echo-sounding techniques came when the piezo-electric effect in certain crystals was discovered by Pierre Curie and his brother Jacques Curie in Paris, France in 1880. They observed that an electric potential would be produced when mechanical pressure was exerted on a quartz crystal such as the Rochelle salt (sodium potassium tartrate tetrahydrate). The reciprocal behavior of achieving a mechanical stress in response to a voltage difference was mathematically deduced from thermodynamic principles by physicist Gabriel Lippman in 1881, and which was quickly verified by the Curie brothers. It was then possible for the generation and reception of 'ultrasound' that are in the frequency range of millions of cycles per second (megahertz) which could be employed in echo sounding devices. Further research and development in piezo-electricity soon followed.

Underwater sonar detection systems were developed for the purpose of underwater navigation by submarines in World war I and in particular after the Titanic sank in 1912. Alexander Belm in Vienna, described an underwater echo-sounding device in the same year. The first patent for an underwater echo ranging sonar was filed at the British Patent Office by English metereologist Lewis Richardson, one month after the sinking of the Titanic. The first working sonar system was designed and built in the United States by Canadian Reginald Fessenden in 1914. The Fessenden sonar was an electromagnetic moving-coil oscillator that emitted a low-frequency noise and then switched to a receiver to listen for echoes. It was able to detect an iceberg underwater from 2 miles away, although with the low frequency, it could not precisely resolve its direction.

The turn of the century also saw the invention of the Diode and the Triode, allowing powerful electronic amplifications necessary for developments in ultrasonic instruments. Powerful high frequency ultrasonic echo-sounding device was developed by emminent French physicist Paul Langévin and Russian scientist Constantin Chilowsky, then residing in France. Patents were filed in France and the United States. They called their device the 'hydrophone'. The transducer of the hydrophone consisted of a mosaic of thin quartz crystals glued between two steel plates with a resonant frequency of 150 KHz. Between 1915 and 1918 the hydrophone was further improved in classified research activities and was deployed extensively in the surveillance of German U-boats and submarines. The first known sinking of a submarine detected by hydrophone occurred in the Atlantic during World War I in April,1916.

Langevin's hydrophones had formed the basis of the development of naval pulse-echo sonar in the following years. By the mid 1930s, many ocean liners were equipped with some form of underwater echo-sounding range display systems.

In another development, the first successful radio range-finding experiment occurred in 1924, when British physicist Edward Appleton used radio echoes to determine the height of the ionosphere. The first practical RADAR system (Radio Detection and Ranging, and using electromagnetic waves rather than ultrasonics) was produced in 1935 by another British physicist Robert Watson-Watt, and by 1939 England had established a chain of radar stations along its south and east coasts to detect aggressors in the air or on the sea. World war II saw rapid developments and refinements in the naval and military radar by researchers in the United States.

Such radar display systems had been the direct precursors of subsequent 2-dimensional sonars and medical ultrasonic systems that appeared in the late 1940s. Books such as the "Principles of Radar" published by the Massachusetts Institute of Technology (M I T) Radar school staff in 1944 detailed the techniques of oscilloscopic data presentation which were employed in medical ultrasonic research later on (see below). Two other engineering advances probably had also influenced significantly the development of the sonar, in terms of the much needed data aqusition capabilities: the first digital computer (the Electronic Numerical Integrator and Computer -- the ENIAC) constructed at the University of Pennsylvania in 1945, and the invention of the point-contact transister in 1947 at AT & T's Bell Laboratories.

Yet another parallel and equally important development in ultrasonics which had started in the 1930's was the construction of pulse-echo ultrasonic metal flaw detectors, particularly relevant at that time was the check on the integrity of metal hulls of large ships and the armour plates of battle tanks.

The concept of ultrasonic metal flaw detection was first suggested by Soviet scientist Sergei Y Sokolov in 1928 at the Electrotechnical Institute of Leningrad. He showed that a transmission technique could be used to detect metal flaws by the variations in ultrasionic energy transmitted across the metal. The resolution was however poor. He suggested subsequently at a later date that a reflection method may be practical.

The equipment suggested by Sokolov which could generate very short pulses necessary to measure the brief propagation time of their returning echoes was not available until the 1940s. Early pioneers of such reflective metal flaw detecting devices were Floyd A Firestone at the University of Michigan, and Donald Sproule in England. Firestone produced his patented "supersonic reflectoscope" in 1941 (US-Patent 2 280 226 "Flaw Detecting Device and Measuring Instrument", April 21, 1942). Because of the war, the reflectoscope was not formally published until 1945. Messrs. Kelvin and Hughes® in England, where Sproule was working, had also produced one of the earliest pulse-echo metal flaw detectors, the M1. Josef and Herbert Krautkrämer produced their first German version in Köln in 1949 followed by equipment from Karl Deutsch in Wuppertal. These were followed by other versions from Siemens® in Erlangen, KretzTechnik AG in Austria, Ultrasonique in France and Mitsubishi in Japan. In 1949, Benson Carlin at M I T, and later at Sperry Products, published "Ultrasonics", the first book on the subject in the English language.

The underwater SONAR, the RADAR and the ultrasonic Metal Flaw Detector were each, in their unique ways, a precursor of medical ultrasonic equipments. The modern ultrasound scanner embraces the concepts and science of all these modalities.

 The early development of ultrasonics is summarised here.  

 Readers are also referred to an article by Dr William O'Brien Jr., which also looks at the early history of the developments of ultrasonics.^