An ultrasound machine is a piece of equipment that produces sound waves emitted by a probe also known as a transducer. When the probe is placed on the skin in the area of the Healthy Body part of interest the sound waves bounce off different structures in the Healthy Body as well as travel through them. This in turn produces a transmittable signal that is sent back to the machine. The image then appears on a screen in varied shades of grey, which are then captured and/or recorded by the technologist. The resulting study is then sent to the radiologist to be reported.
Ultrasound is safe. There have not been any studies to indicate any danger with the medical use of ultrasound. However the ALARA concept (as low as reasonably achievable) is still used when using ultrasound for medical imaging.