Different sound velocities in tissue are causing refraction artifacts. With convex elastomer lens transducers, sound beam refraction at the skin interface can alter the transducer's focusing characteristics and beam profile, cause element to element nonuniformity, and cause phase changes in the acoustic wave. These cumulative refraction induced errors degrade the image quality through distortion and loss of resolution. Because the amount of refraction is proportional to the velocity mismatch, the greater the mismatch, the greater the refraction.

Reverberation artifacts are produced from the multiple reflections from an object if the acoustical impedances of tissue layers are too much different and the detected echo does not run the shortest sound path because it bounces back and forth between the object and the transducer. In a reverberation artifact, the sound wave is reflected back into the body from the transducer-skin interface.

Ringing means the rise and decay time before and after the transducer reaches the maximum amplitude. Expressed as the mechanical Q of the transducer, which is the number of cycles it takes to get up to 90% of maximum amplitude or down to 10% above zero amplitude.

'China based Shantou Institute of Ultrasonic Instruments (SIUI) has been engaged in the development and manufacture of medical ultrasonic diagnosis scanners, industrial ultrasonic detectors and ultrasonic transducers since the early 1960's. Starting as a small scientific research institute, SIUI has developed into a key high-tech corporation at the national level, and is the leading manufacturer of ultrasonic instruments in China.'
'SIUI is dedicated to providing all customers with the ultrasonic scanners of high quality and reasonable price. The annual production amounts to 5,000 ultrasonic scanners and 10,000 transducers. SIUI takes the lead in attaining ISO9001 certification, FDA clearance and CE marking in China. Due to the high ratio of performance to price as well as the guarantee on quality, the products are exported to over 80 countries and areas around the world. The export volume ranks No. 1 in this field in China. The market share continues to improve.'

Ultrasound Systems:

From Siemens Medical Systems;
'The SONOLINE G20™ ultrasound system quickly distances itself from the competition with next-generation all-digital system architecture that utilizes Siemens technology migration. Individual imaging parameters have been optimized for a wide variety of clinical applications and patient types. So you can realize a higher degree of diagnostic confidence. Without doubt.'