User's Manual
Table Of Contents
- M-Turbo Ultrasound System User Guide
- Contents
- Introduction
- Chapter 1: Getting Started
- Chapter 2: System Setup
- Displaying the setup pages
- Restoring default settings
- A & B Key, Footswitch setup
- Administration setup
- Annotations setup
- Audio, Battery setup
- Cardiac Calculations setup
- Connectivity setup
- Date and Time setup
- Display Information setup
- IMT Calculations setup
- Network Status setup
- OB Calculations setup
- OB Custom Measurements setup
- OB Custom Tables setup
- Presets setup
- System Information setup
- USB Devices setup
- Chapter 3: Imaging
- Chapter 4: Measurements and Calculations
- Chapter 5: Troubleshooting and Maintenance
- Chapter 6: Safety
- Ergonomic safety
- Electrical safety classification
- Electrical safety
- Equipment safety
- Battery safety
- Clinical safety
- Hazardous materials
- Electromagnetic compatibility
- ALARA principle
- Acoustic artifacts
- Guidelines for reducing MI and TI
- Output display
- Transducer surface temperature rise
- Acoustic output measurement
- Acoustic output tables
- Labeling symbols
- Chapter 7: References
- Chapter 8: Specifications
- Glossary
- Index
Chapter 6: Safety 107
Safety
Fixed‐pathtissuemodels,inwhichsofttissuethicknessisheldconstant,sometimesareusedto
estimateIn Situacousticexposureswhenthebeampathislongerthan3cmandconsistslargely
offluid.Whenthismodelisusedtoestimatemaximumexposuretothefetusduring
transabdominalscans,avalueof
1dB/cmMHzmaybeusedduringalltrimesters.
Existingtissuemodelsthatarebasedonlinearpropagationmayunderestimateacoustic
exposureswhensignificantsaturationduetonon‐lineardistortionofbeamsinwaterispresent
duringtheoutputmeasurement.
Themaximumacousticoutputlevelsofdiagnosticultrasounddevicesextendoverabroad
rangeofvalues:
•Asurveyof1990‐equipmentmodelsyieldedMIvaluesbetween0.1 and1.0attheirhighest
outputsettings.MaximumMIvaluesofapproximately2.0areknowntooccurforcurrently
availableequipment.MaximumMIvaluesaresimilarforreal‐time2DandMModeimaging.
•Computedestimatesof upperlimitsto
temperatureelevationsduringtransabdomina lscans
wereobtainedinasurveyof1988and1990pulsedDopplerequipment.Thevastmajorityof
modelsyieldedupperlimitslessthan1°and4°C(1.8°and 7.2°F)forexposuresof
first‐trimesterfetaltissueandsecond‐trimesterfetalbone,respectively.Thelargestvalues
obtained
wereapproximately1.5°C(2.7°F)forfirst‐trimesterfetaltissueand7°C(12.6°F)for
second‐trimesterfetalbone.Estimatedmaximumtemperatureelevationsgivenherearefor
a“fixedpath”tissuemodelandarefordeviceshavingI
SPTA
valuesgreaterthan500 m W/
cm
2
.Thetemperatureelevationsforfetalboneandtissuewerecomputedbasedon
calculationproceduresgiveninSections4.3.2.1‐4.3.2.6in“BioeffectsandSafetyofDiagnostic
Ultrasound”(AIUM,1993).
Acoustic output tables
Table 8throughTable 31indicatetheacousticoutputforthesystemandtransducer
combinationswithaTIorMIequaltoorgreaterthanone.Thesetablesareorganizedby
transducermodelandimagingmode.Foradefinitionoftermsusedinthetables,see“Terms
usedintheacousticoutputtables”
onpage 132.