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Chapter 3
April 2017
bk3500 User Guide
(16-01410-EN-04)
Functions Affecting Acoustic Output
The system has a control function that ensures that neither the I
SPTA
nor MI nor TI
value exceeds the maximum allowable value. When necessary, the system will
reduce the output voltage and/or PRF (pulse repetition frequency) to the transducer
to comply with requirements.
Some of the system functions can affect the acoustic output, as listed here.
(Instructions for using these functions are given in the relevant sections of this user
guide.)
•
Sizing functions such as ROI (Region Of Interest) – in general, smaller size
results in higher acoustic intensity because the Pulse Repetition Frequency
(PRF) is higher or the ultrasound beam is more strongly focused.
•
Focus – in general, strongly focusing the beam makes the acoustic intensity
higher.
•
Frame rate – higher frame rate results in higher acoustic intensity.
•
Range – increasing the Doppler range increases the acoustic intensity by
increasing the PRF.
•
CFM Resolution – higher resolution increases the acoustic output.
•
Color box size – narrowing the color box generally increases the acoustic output
within it.
The user can set a Thermal Index limit. This will provide an upper limit for acoustic
output.
Default Acoustic Output
After the system
has been turned off, the transducers will start in the default setup
when the system is turned on again. The default setup may be factory-defined or
defined by the user.
The factory-defined default setup values of acoustic output for each transducer are
listed in the Technical Data (BZ2100).
These setups have been optimized to give the best compromise between low acoustic
output and enough power to obtain the image features as quickly as possible. The
factory default setup for all transducers is B-Mode to ensure the lowest acoustic
output when you start imaging.
When you enter a new patient ID, by default the transducer setup will be reset to the
factory setup.
Fetal imaging
When you use transducers intended for fetal imaging, it is important to make sure
that the default settings are appropriate and to reset to the default setting before
imaging a new patient.
Clinical Measurements: Ranges and Accuracies
This section states the accuracies for measurements made using the BK range of
ultrasound systems. A table containing accuracies for specific transducers can be
found in the Technical Data (BZ2100) that accompanies this user guide.
