What is diagnostic ultrasound?
- We use inaudible sound (frequencies between 2-18MHz) to scan organs, joints and blood vessels.
- A transducer or probe is used to scan an organ, limb or joint.
- We use higher frequencies for more superficial organs and lower for deeper organs.
- A sound wave of known frequency is sent into an organ, the tissue (depending on density) changes the wavelength and sends it back to the probe. The ultrasound machine then uses the altered wave length to produce a live picture on the machine screen.
- The denser the tissue, the whiter the image and the less dense tissues produce a grey image. Clear fluid produces a black image which helps with the delineation of anatomy and pathology.