Ultrasound (Sonography) Technology, In diagnostic ultrasound, the different propagation of ultrasonic waves is utilized in the human body: the high-frequency sound waves transmitted into the body by the examining physician via a special transducer, whose frequency is 20 kilohertz to 1 gigahertz above the human auditory threshold, become the boundary layers between tissues Differently reflected. The transducer receives the emitted sound waves. From these, the computer calculates an image on which different tissue types are represented. In the case of contrast medium ultrasound, small gas-filled bubbles (echo contrast enhancers) are injected into the patient’s blood stream. In the ultrasonic field, they begin to oscillate, so that the blood flow of the tissue is visible on the screen. The doctor can identify the type of tumor by means of typical blood flow patterns.
The sound waves used in the ultrasound are harmless to the patient, a radiation exposure does not occur. However, the ultrasonic waves do not reach deeper organs. In order to investigate organs such as the prostate, fallopian tube or uterus with ultrasound waves, instruments have been developed that are inserted into the natural bodily openings (eg mouth, anus, vagina) and provide images from the interior of the organs (endoscopic ultrasound of the bronchi Endobronchial ultrasound, EBUS).