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
106
Attenuationfactor(a)forvarioustissuetypesaregivenbelow:
brain=0.53
heart=0.66
kidney=0.79
liver=0.43
muscle=0.55
l=skinlinetomeasurementdepthincm
f=centerfrequencyofthetransducer/system/modecombinationinMHz
Sincetheultrasonicpathduringtheexamislikelytopassthrough
varyingleng ths andtypes
oftissue,itisdifficulttoestimatethetrueIn Situintensity.Anattenuationfactorof0.3isused
forgeneralreportingpurposes;therefore,theIn Situvaluecommonlyreportedusesthe
formula:
In Situ(derated)=Water[e
‐(0.069lf)
]
SincethisvalueisnotthetrueIn Situintensity,theterm“derated”isusedtoqualify it.
Themaximumderatedandthemaximumwatervaluesdonotalwaysoccuratthesame
operatingconditions;therefore,thereportedmaximumwaterandderatedvaluesmaynotbe
relatedbytheIn Situ(derat ed)formula.For
example:amulti‐zonearraytransducerthathas
maximumwatervalueintensitiesinitsdeepestzone,butalsohasthesmallestderatingfactor
inthatzone.Thesametransducermayhaveitslargestderatedintensityinoneofitsshallowest
focalzones.
Tissue models and equipment survey
TissuemodelsarenecessarytoestimateattenuationandacousticexposurelevelsIn Situfrom
measurementsofacousticoutputmadeinwater .Currently,availablemodelsmaybelimitedin
theiraccuracybecauseofvaryingtissuepathsduringdiagnosticultrasoundexposuresand
uncertaintiesintheacousticpropertiesofsofttissues.Nosingletissuemodel
isadequatefor
predictingexposuresinallsituationsfrommeasurementsmadeinwater,andcontinued
improvementandverificationofthesemodelsisnecessaryformakingexposureassessments
forspecificexamtypes.
Ahomogeneoustissuemodelwithattenuationcoefficientof0.3 dB/cm MHzthroughoutthe
beampathiscommonlyusedwhenestimatingexposurelevels.
Themodelisconservativein
thatitoverestimatestheIn Situacousticexposurewhenthepathbetweenthetransducerand
siteofinterestiscomposedentirelyofsofttissue.Whenthepathcontainssignificantamounts
offluid,asinmanyfirstandsecond‐trimesterpregnanciesscannedtransabdominally,this
modelmayunderestimate
theIn Situacousticexposure.Theamountofunderestimation
dependsuponeachspecificsituation.