Sun Kingdom SK-3000A, Инструкция по эксплуатации

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A-scan ultrasound show reflected signal which is from interface in human body as
vertical peak, form an image. The ultrasonic wave transmission time represents distance
of reflecting interface, the further the distance, the later position of peak .the height of
peak represent echogenicity, the stronger of echo, the higher of peak. The echo
amplitude obtained is A-Scan ultrasound echogram.
B-scan theory
B-scan ultrasound send out a set of ultrasonic to human body, scanning according to
a certain direction, transfer the interface echo to echo spot in different brightness , all
these light spot form a 2D series section images.
Pachymetry theory
Pachymetry cornea thickness measurement :When the ultrasonic pulse strikes the
first interface, one part of the acoustic wave is reflected, the other part of the acoustic
wave penetrates the first interface and continues to move to the second interface, and
then another part of the ultrasonic wave is reflected by the second interface. The corneal
thickness can be calculated by measuring the distance between the two peaks produced
by the two reflections of ultrasound.
Velocity
Sound wave has different velocity in different medium, sound velocity is associated
with medium density and medium temperature. The velocity in anterior chamber and
vitreous body is 1532m/s
，
the velocity in lens range from 1590-1670m/s according to
different opacification degree, general use 1641m/s.
Detected results analysis
A-scan ultrasound allows for measuring the anterior chamber depth, lens thickness
and vitreous depth of eyes (corneal thickness included in anterior chamber).The visual
axis length from cornea to retina average in 22-24.5mm, age-related decreasing of
anterior chamber depth, thickness of lens between 3.5-4.5mm, lens thickness is