The Doppler effect, which describes the change in frequency or wavelength of a wave due to the relative motion between the source and observer, has significant applications in medicine, particularly through the use of Doppler ultrasound. This non-invasive imaging technique leverages the Doppler effect to assess blood flow and other dynamic processes in the body. Below are some key medical applications of the Doppler effect, informed by the context of the X post you found interesting and supplemented with up-to-date knowledge: