Siemens ACUSON Freestyle, User Manual, Page: 32 / 138

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ACUSON
Freestyle User Manual
Safety and Care
Acoustic Output: Global Maximum Values
No system/transducer combination is capable of exceeding either a Thermal Index (TI) of 1.0 or
a Mechanical Index (MI) of 1.0, so, in accordance with relevant standards (NEMA UD3-2004),
the system does not display MI or TI. The table below, Global Maximum Values, provides the
mean of the global maximum of acoustic output values. The terms are described below.
Table entries have been obtained with the same operating conditions that create the maximum
value.
Uncertainties associated with the values derive from transducer and system variability,
measurement variability, and engineering approximations for real-time calculations.
Measurement precision and uncertainty for quantities used to calculate the values in the table
are 30% for intensity and 15% for MI.
Maximum surface temperatures are in accordance with IEC 60601-2-37.
References:
Ziskin MC: “Measurement of uncertainty in ultrasonic exposimetry”, Ultrasonic Exposimetry ,
M.C. Ziskin and P.A. Lewin, eds. (CRC Press, Boca Raton, FL) pp. 409-443, 1993.
Ziskin MC: “Specification of acoustic output level and measurement uncertainty in ultrasound
exposimetry,” IEEE Transactions Ultrasonics, Ferroelectrics, and Frequency Control , 50, 1023-
34, 2003