NEMA revises ultrasound standards
The National Electrical Manufacturers Association (NEMA) has released two revised standards for ultrasound users who want to measure the performance of their equipment.

UD 2-2004, Acoustic Output Measurement Standard for diagnostic ultrasound equipment, describes a set of measurement procedures for ultrasonic output parameters. Appendix A, "Statistical Considerations," was revised to include discussions of the one-sided tolerance limit for normal distributions, Type A and Type B uncertainty specifications, and multiple console/transducer combinations for a particular model, none of which were addressed in the previous version, said NEMA.

UD 3-2004, Standard for Real-Time Display of Thermal and Mechanical Acoustic Output Indices on Diagnostic Ultrasound Equipment, enables users to monitor acoustic output display in real time during the course of an ultrasound examination.

According to NEMA, the standard was revised to include discussions of how equipment will display the best estimate of the mean index values; a description of the display uncertainty will be included in the operator's instruction manual. Other changes were made to make the document compatible with IEC 60601-2-37, medical electrical equipment-Part 2-37: particular requirements for the safety of ultrasonic medical diagnostic and monitoring equipment (2001), according to NEMA.

UD 2-2004 can be purchased for $128 by visiting ; UD 3-2004 can be purchased for $72 by visiting or by contacting Global Engineering Documents at 800-854-7179 (within the U.S.), 303-397-7956 (international), or 303-397-2740 (fax).