Samsung MYSONO U6 Bedienungsanleitung PDF herunterladen (Seite 46)

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Operation Manual

The maximum derated and the maximum water values do not always occur under the same operating

conditions; therefore, the reported maximum water and derated values may not be related to the In

Situ (derated) formula. For example, a multi-zone array transducer that has the greatest water value

intensities in its deepest zone. the same transducer may have its largest derated intensity in one of its

shallowest focal zones.

Acoustic Output and Measurement

Since the rst usage of diagnostic ultrasound, the possible human biological eects (bioeects)

of ultrasound exposure have been studied by various scientic and medical institutions. In

October 1987, the American Institute of Ultrasound in Medicine(AIUM) ratied a report prepared

by its Bioeects Committee (Bioeects Considerations for the Safety of Diagnostic Ultrasound, J

Ultrasound Med., Sept. 1988: Vol.7, No.9 Supplement), sometimes referred to as the Stowe Report,

which reviewed available data on the possible eects of ultrasound exposure. Another report

“Bioeects and Safety of Diagnostic Ultrasound”, dated January 28, 1993, provides more up to date

information.

The acoustic output for this system has been measured and calculated in accordance with the

December 1985 “510(K) Guide for Measuring and Reporting Acoustic Output of Diagnostic

Ultrasound Medical Devices”, except for the hydrophone, which meets the requirements of “Acoustic

Output Measurement Standard for Diagnostic Ultrasound Equipment” (NEMA UD 2-1992).

The terms and symbols used in the acoustic output tables are dened in the following paragraphs.

ISPTA.3 Derated spatial-peak temporal-average intensity (milliwatts per square

centimeter).

ISPPA.3 The derated spatial-peak pulse-average intensity (watts per square centimeter).

The value of IPA.3 at the position of global maximum MI (IPA.3@MI) may be reported

instead of ISPPA.3 if the global maximum MI is reported.

MI The Mechanical Index. The value of MI at the position of ISPPA.3, (MI@ISPPA.3) may

be reported instead of MI (global maximum value) if ISPPA.3 is 190W/cm

Pr.3 The derated peak rarefactional pressure (megapascals) associated with the transmit

pattern giving rise to the reported MI value.

WO The ultrasonic power (milliwatts). For operating conditions giving rise to ISPTA.3, WO

is the total time-average power. For operating conditions subject to reporting under

ISPPA.3, WO is the ultrasonic power associated with the transmit pattern giving rise

to the value reported under ISPPA.3.

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