Orange County Biomedical Equipment Technicians Society

Vol. 4 No 2 February 1997 

January Meeting Minutes

The January meeting was sponsored by Richardson Electronics, Ltd. In business since 1947, with sales of over $240 million, Richardson Electronics is a value added distributor and manufacturer with 58 offices and 18 stocking warehouses worldwide. Products are X-Ray tubes, Image Intensifiers, Camera Tubes, Pulse and Switch Tubes, Video Products, Hydrogen Thyratrons, Magnetrons, 

CRT's, High Voltage Cables, Accessories, and Semiconductors. 

Attendance: Stan Richards, Donna Shea, Steve Newman, James Usher, Danny Bower, Tom Gottschalk, Daniel Thebault, Bob Hernandez, Wayne Harrington, Tom Heyser, and Dean Fanara

REFERENCE MATERIAL

Ultrasound Scanning Modes 

A-mode scanning refers to amplitude mode scanning that measures tissue discontinuity along the scan axis. A-mode displays the magnitude of the signal as a spike in one dimension, Y, versus the depth or time for return of the echo signal in the other dimension, X. 

B-mode scanning produces a two-dimensional image o the tissue under study by combining A-mode signals from various directions through mechanical transducer scanning. 

M-mode, or time motion scanning (formally TM-mode), is an extension of the A-mode approach, in which a single stationary transducer is used. The depth of the echo is displayed on the vertical axis: the brightness of the display is modulated by the echo amplitude. M-mode scanning is very useful in evaluating moving structures, such as valves of the heart and the motion of the heart wall. This application of M-mode scanning is known as echocardiography. 

Real-time mode, or rapid B-scanning techniques, provides continuous data acquisition at a rate sufficient to give the impression of instantaneous motion of moving structures. Real-time scanning is used extensively in obstetrics, as no ionizing radiation is involved. It has also found applications in vascular imaging of major vessels and quick localization of structures to identify areas for further evaluation with static B-mode imaging. 

Doppler scanning relies on the presence of motion. The Doppler effect occurs when there is relative motion between the source of sound and the receiver of sound, causing a change in the detected frequency of the sound source. 

Source Affinity Reference Guide for Biomedical Technicians, Leslie R. Atles, Scott Segalewitz, Copyright 1995 Marquette Electronics, Inc.