Siemens ACUSON S Series User Manual

ACUSON Freestyle User Manual 2-15
Safety and Care
Accuracies
Measurement Accuracies
The ACUSON Freestyle may be used to provide measurements and calculations derived from
ultrasound images. The quantied image data may be used along with other clinical information
to assist a physician in making a patient diagnosis.
The sole reliance on diagnostic ultrasound data to make a clinical diagnosis is not
recommended. Numerous factors related to the accuracy of ultrasound image data must be
taken into account. This section describes some of these factors. Measurement accuracies are
also inuenced by operator experience, scanning technique, interpreting physician experience,
and the technical difculty of the patient. Many of these variables are not associated with the
ACUSON Freestyle system. This limits the ability to fully specify the clinical accuracy of the
measurements and calculations provided by the system.
Accuracy by Transducer Type
All transducer types have been veried for measurement accuracy in the modes appropriate to
each measurement type.
Because the moderate transducer frequency range of the system, measurement accuracies for
the system are not expected to vary signicantly based on transducer used.
Accuracy of Primary Measurements
All reported accuracies are +/– one-half the least signicant digit.
Distance
The system assumes that the speed of sound in tissue is 1540 meters per second and that
this speed is homogeneous in all tissues. The diagnostic ultrasound literature states that
differences in the speed of sound in the body do exist because of the differing tissue types. In
Clinical Sonography – A Practical Guide, (2nd Edition, Roger C. Sanders, ed., Little Brown and
Company 1991) the range is cited as from 1500 to 1600 meters per second. These differences
would produce an inaccuracy of up to +/– 4%.
The distance measurements on the system are veried using an AIUM standard phantom
with a uid having an acoustic speed of approximately 1540 meters per second at room
temperature. The accuracy of this measurement is +/– 5%. The maximum range of this
measurement is 24 cm (dependent on the probe).
Area
The accuracy of the area measurement is +/– 10%.
The maximum range of this measurement is 733 cm
2
(dependent on the probe).

Siemens ACUSON S Series Specifications

General

Power Requirements	100-240 VAC, 50/60 Hz
Operating Modes	B-mode, M-mode, Color Doppler, Power Doppler
Ports	Ethernet, USB
Operating Temperature	10°C to 40°C
Humidity	30% to 75% (operating)
Supported Imaging Modes	Contrast Imaging
Display Type	High-resolution LCD