Chison ECO 1VET, Руководство по эксплуатации

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ECO Series VET Digital Color Doppler Ultrasound System
13
Thermal Models Composition Mode Specification Application
2
TIS Soft tissue Unscanned
Small aperture
(<1cm
2
)
Pencil Probe
3
TIS Soft tissue Scanned
Evaluated at
surface
Breast color
4
TIB Soft tissue and bone Scanned
Soft tissue at
surface
Muscle color
5 TIB Soft tissue and bone Unscanned Bone at focus Fetus head PW
6 TIC Soft tissue and bone Unscanned/scanned Bone at surface Transcranial
Soft tissue:
Describes low fat content tissue that does not contain calcifications or large gas-filled spaces.
Scanned: (auto-scan)
Refers to the steering of successive burst through the field of view, e.g. B and color mode.
Unscanned:
Emission of ultrasonic pulses occurs along a single line of sight and is unchanged until the transducer is moved
to a new position. For instance, the PW, and M mode.
TI:
TI is defined as the ratio of the In Situ acoustic power (W.3) to the acoustic power required to raise tissue
temperature by 1°C (Wdeg), TI = W.3/Wdeg.
Three TIs corresponding to soft tissue (TIS) for abdominal; bone (TIB) for fetal and neonatal cephalic; and
cranial bone (TIC) for pediatric and adult cephalic, have been developed for applications in different exams.
An estimate of the acoustic power in milli-watts necessary to produce a 1°C temperature elevation in soft
tissue is:
Wdeg = 210/fc,for model 1 to 4, where fc is the center frequency in MHz.
Wdeg = 40 K Dfor model 5 and 6, where K (beam shape factor) is 1.0, D is the aperture diameter in cm at
the depth of interest.
MI:
Cavitation is more likely to occur at high pressures and low frequencies in pulse ultrasound wave in the tissue,
which contains the bubble or air pocket (for instance, the lung, intestine, or scan with gas contrast agents). The
threshold under optimum conditions of pulsed ultrasound is predicted by the ration of the peak pressure to the
square root of the frequency.
MI = Pr’ / sqrt(fc)
Pr’ is the de-rated (0.3) peak rare-fractional pressure in Mpa at the point where PII is the maximum, and fc is
the center frequency in MHz. PII is the Pulse Intensity Integral that the total energy per unit area carried by the
wave during the time duration of the pulse. The peak rare- fractional pressure is measured in hydrophone
maximum negative voltage normalized by the hydrophone calibration parameter.
Display Guideline: