Device Standards
HD11 XE Getting Started
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Restrictions for Use
The physician needs to determine if an artifact caused by radiated interference
will have a negative impact on image quality and the subsequent diagnosis.
Immunity Level Test Results
The EMC standards state that manufacturers of patient-coupled equipment must
specify immunity levels for their systems. It is recognized that this type of device is
designed to receive and amplify low-level signals in the same bandwidth as the
interference.
Immunity is defined in the standard as the ability of a system to perform without
degradation in the presence of an electromagnetic disturbance. Degradation in
image quality is a qualitative assessment that can be subjective. The simplest way
to assess degradation is to note when the first sign of an artifact is seen in the
image. This method has two advantages. It removes the issue of subjective deci-
sion making and it provides the most stringent test results.
Be cautious when comparing immunity levels of different ultrasound systems. The
criteria used for degradation is not specified by the standard and may vary with
the manufacturer.
Testing has been performed on each class of Philips transducer for every operat-
ing mode over a wide range of frequencies.
Table 6-9 lists the results of immunity testing. Testing was performed on a typical
ultrasound system configuration.
NOTE
Electrostatic discharges (ESDs) may cause the ECG heart rate display to increase
by 10% to 15% for a few seconds after the discharge. However, the ECG heart
rate display will return to normal within 4 seconds.
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