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ULTRASOUND POWER METERS
UPM SERIES ULTRASOUND POWER METERS: NIST & FDA TESTED
These time proven wattmeters, first introduced in 1977, are used by Biomeds & Physio-Therapists to calibrate or verify the accuracy of therapeutic and diagnostic ultrasound equipment. Power range is up to 30 Watts with resolution to 2mW. Frequency range: 1-10MHz. The UPM Series power meters meet FDA, AIUM, AMMI and JCAHO test requirements. The precision of these wattmeters is documented to perform within the limits of uncertainty of FDA and NIST standards. Direct power measurement, in watts, is made by converting the acoustical force applied to a cone target, linked to a mechanical balance beam or an electronic load cell. The UPM-DT models feature precise digital readout, autozeroing and a bi-directional RS-232 interface. All UPM Series Power Meters are supplied with a carrying case.
WATTMETER SELECTION GUIDE
The FDA requires the measurement of ultrasound power levels to determine exact patient exposure and to minimize potential risks. Health care facilities are responsible for regularly scheduled testing (every 6 months) of output power and safety to maintain their accreditation. Typical safe values are defined by the temporal average intensity at the point in the acoustic field where the intensity is at its maximum value, referred to as SPTA (Spatial Peak Temporal Average). The FDA and AIUM provide guidelines for the maximum SPTA values in medical applications. Typical safe SPTA values are 10mW/cm2 for echo sounding, 100mW/cm2 for Doppler devices and 3W/cm2 for therapeutic use. The watt density (watts/cm2) of a transducer is determined by measuring the total power output and dividing by the cross sectional area of the radiating surface.