The development history of ultrasound imaging (part 2)
George Ludwig received a bachelor's degree in chemistry from St. Vincent's College in 1944 and a medical degree from the University of Pennsylvania in 1946. After graduation, from 1947 to 1949, Ludwig served as a lieutenant at the Naval Medical Institute in Betheda, Maryland. There, he began to use a-type industrial flaw detection equipment (originally with a Sperry mirror) to conduct experiments on animal tissues. Ludwig used the reflective pulse-echo ultrasound method and designed some experiments to detect the presence and location of foreign objects in animal tissues, especially for the location of gallstones, similar to radar and sonar when detecting foreign ships and flying objects. The method used. Develop ultrasonic technology into a practical technique for detecting gallstones.
In 1949, he published a 49-page report that systematically introduced the use of ultrasonic pulse echo technology to realize the positioning and detection of internal organs and lesions in the human body. It mentioned the measurement process of the average velocity in soft tissues. . Knowing the propagation speed of ultrasound in soft tissues is the basis of ultrasound positioning. It can be said that the work of George Ludwig was the pioneer work of various ultrasound diagnostic instruments. In 1950, George Ludwig published this work in the Journal of the Acoustic Society of America. George Ludwig later invented a commercial ultrasonic diagnostic apparatus called "UltrasonicLocator".
However, George Ludwig was clearly not a business talent, and his ambitious business plan ended in failure. After that, Ludwig focused on metabolism, endocrine and molecular diseases at Massachusetts General Hospital and other institutions, as well as on abnormal heme, porphyrin, indole, calcium phosphate metabolism, parathyroid disease and natural metabolic abnormalities. Made a special contribution. In 1973, Ludwig died of a sudden cerebral hemorrhage at the age of 51. The pioneer of ultrasound medicine who died young did not catch up with the golden age of ultrasound diagnosis.
The commercial use of ultrasound equipment can be traced back to 1963, at which time the B-mode ("luminance mode") equipment had been invented, allowing the examiner to obtain visual and intuitive two-dimensional images. In the mid-1970s, the introduction of "gray scale" (Kossoff, Garrett) directly led to the invention of real-time ultrasound scanners. Ten years later, the invention of a device based on the Doppler effect made the flow of blood visualized. Ultrasound diagnosis has entered the era of functional evaluation from structural evaluation.
