B-SCANNER

Typical Number in Hospital: 5

Cost Bands: 6

References: 1

This is an ultrasonic device employing pulsed ultrasound in the megahertz (MHz) range which records the depth from which echoes arise and the position in an X-Y plane. Depth into the body is usually displayed on the Y-axis of a CRT, distance along the skin surface in the direction of the scan is displayed on the X-axis and the echo amplitude is presented via the Z-modulation (brightness).

B-scanners were first used in the early 1960s for visualization of the foetus in utero, but have since been used for examining other organs within the body such as the heart, liver, kidneys, thyroid, bladder, spleen, and eyes.

Early B-scanners used a single transducer to send the ultrasound pulses and to detect the returning echoes. The transducer was moved over the skin manually so that the picture (a section) was built up over 10-15 seconds. Now the majority of ultrasonic scanners can produce a moving picture, either with a multi-element transducer which steers the ultrasound beam electronically, or the scanning motion is achieved using a rocking or rotating transducer or mirror.

B-scanners are found in X-ray departments and sometimes in ante-natal units. The main components are the transducer, a pulse generator, an echo amplifier, video drive circuits, beam steering and registration circuits and a display device, which may now include a computer type memory or scan converter to retain the image and allow some post-capture processing of the image.