F15 Series Fetal & Maternal Monitor User Manual Ultrasound Intensity and Safety
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TIB (Bone Thermal Index): It provides an estimate of potential temperature rise when the ultrasound
beam passes through soft tissue and a focal region is in the immediate vicinity of bone.
TIC (Cranial Bone Thermal Index): It provides an estimate of potential temperature rise in the cranial
bones or superficial bones.
A4.3.3 Measurement Uncertainty
The uncertainties in the measurements were predominantly systematic in origin; the random
uncertainties were negligible in comparison. The overall systematic uncertainties were determined as
follows.
1. Hydrophone Sensitivity
Based on the HNP-0400 hydrophone calibration certificate, the hydrophone measurement uncertainty
for 1-15MHz is 1 dB, which is equivalent to an uncertainty of ±12.20% for intensity and ±6.10% for
pressure. This uncertainty is used in PW measurement uncertainty assessment.
2. Digitizer
Based on the oscilloscope calibration certificate, the oscilloscope uncertainty is ±1.16% for intensity
and ±0.58% for pressure.
3. Temperature
Based on the temperature variation of the water bath, the uncertainty is ±1.6% for intensity and ±0.8%
for pressure.
4. Spatial Averaging
±10.2% for intensity, and ±6.1% for pressure.
5. Non-linear Distortion:
N/A. No effects of nonlinear propagation were observed.
Since all the above error sources are independent, they may be added on an RMS basis, giving a total
uncertainty of ±26.62 percent for all intensity values reported, ±13.31 percent for all the pressure
values and ±14.52 percent for the Mechanical Index.
A4.4 Prudent Use Statement
Although no confirmed bioeffects on patients caused by exposure from present diagnostic ultrasound
equipment have ever been reported, the potential exists that such bioeffects may be identified in the
future. Therefore, the ultrasound should be used prudently. High levels of acoustic output and long
exposure time should be avoided while acquiring necessary clinical information.
A4.5 References for Acoustic Output and Safety
1. “Bioeffects and Safety of Diagnostic Ultrasound” issued by AIUM in 1993
2. “Medical Ultrasound Safety” issued by AIUM in 1994
3. "Marketing Clearance of Diagnostic Ultrasound Systems and Transducers" issued in 2019.
4. "Medical electrical equipment—Part 2-37: Particular requirements for the basic safety and
essential performance of ultrasonic medical diagnostic and monitoring equipment" issued by IEC
in 2015.
Traditional 510(k) of Fetal & Maternal Monitor
014_14.1_F15_Series_User_Manual
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