The echo location is the location of a target relative to the sensor face. The echo is located by measuring the time that it takes for a sound wave to travel to the target and be reflected back to the sensor.

See also Time of Flight.

The specular echo originates from relatively large, strongly reflective, regularly shaped objects with smooth surfaces. These intense reflections are angle dependent, and are described by reflectivity equation. This type of reflection is called specular reflection (i.e. IVS, valves).

See also False Distance Artifact, and Scattered Echo.

The scattered echo originates from relatively small, weakly reflective, irregularly shaped objects, and is less angle dependent and less intense. The mathematical treatment of non-specular reflection involves the Rayleigh probability density function (i.e. blood cells).

EchoSeed™ consists of radioactive 125I (iodine-125) seeds/implants indicated for the treatment of prostate cancer with brachytherapy.
The design of this second generation product, used in combination with ultrasound imaging, facilitates optimal placement. EchoSeed™ allows the physician to view both the prostate gland and the seeds during the course of the implant procedure.
Nycomed Amersham. Source: PR Newswire - 06/04/01.

An echo is defined as the repetition of a sound by reflection of sound waves from a surface.
Echo types used in ultrasound imaging:
Specular echoes are created from relatively large, regularly shaped objects with smooth surfaces. Specular echoes are relatively intense and angle dependent.
Scattered echoes are created from relatively small, weakly reflective, irregularly shaped objects. Scattered echoes are less angle dependant and less intense.

See also Specular Echo, and Scattered Echo.