NEMA UD 2

Abstract

This standard covers all active ultrasound apparatus designed for medical diagnostic use, including ultrasonic echo ranging devices (both manual and automatically <strong>scanned</strong>), through-transmission devices, Doppler echo equipment, and combinations thereof. <br>This document establishes measurement standards for acoustic output quantities of ultrasonic diagnostic equipment. <br>Measurements of acoustic output quantities are to be performed in water. However, in order to provide values more typical of what might occur within tissue, derated values of output quantities will be required in addition to the in-water values. To provide an example, detailed derating procedures and requirements are discussed in this standard for a specific model; this is a 0.3 dB/cm-MHz uniform attenuation model, and will be notationally designated by the subscript &#8220;.3,&#8221; i.e., I_SPPA.3. <br>It is anticipated that in the future, different <strong>derating factors</strong> will be necessary to better represent different applications. The standard provides for the implementation of different derating schemes by the manufacturer, provided that the implementation of that scheme is described.