User's Manual

Table Of Contents
Chapter 6: Safety 103
Safety
EvenwhenMIislessthan1.0,thesystemprovidesacontinuousrealtimedisplayofMIinall
imagingmodes,inincrementsof0.1.
ThesystemmeetstheoutputdisplaystandardforTIandprovidesacontinuousrealtime
displayofTIinallimagingmodes,inincrementsof0.1.
The
TIconsistsofthreeuserselectableindices,andonlyoneoftheseisdisplayedatanyone
time.InordertodisplayTIproperlyandmeettheALARAprinciple,theuserselectsan
appropriateTIbasedonthe specificexambeingperformed.SonoSiteprovidesacopyofAIUM
MedicalUltrasound
Safety,whichcontainsguidanceondeterminingwhichTIisappropriate (See
“Relatedguidancedocuments”onpage 104).
MI and TI output display accuracy
Theaccuracy resultfortheMIisstatedstatistically.With95%confidence,95%ofthemeasured
MIvalueswillbewithin+18%to‐25%ofthedisplayedMIvalue,or+0.2ofthedisplayedvalue,
whichevervalueislarger.
TheaccuracyresultfortheTIisstatedstatistically.With95%confidence,
95%ofthemeasured
TIvalueswillbewithin+21%to‐40%ofthedisplayedTIvalue,or+0.2ofthedisplayedvalue,
whichevervalueislarger.Thevaluesequateto+1dB to‐3dB.
Adisplayedvalueof0.0forMIorTImeansthatthecalculatedestimatefortheindex
islessthan
0.05.
Factors that contribute to display uncertainty
Thenetuncertaintyofthedisplayedindicesisderivedbycombiningthequantifieduncertainty
fromthreesources:measurementuncertainty,systemandtransducervariability,and
engineeringassumptionsandapproximationsmadewhencalculatingthedisplayvalues.
Measurementerrorsoftheacousticparameterswhentakingthereferencedataarethemajor
sourceoferror
thatcontributestothedisplayuncertainty.Themeasurementerrorisdescribed
in“A c o u s t i c measurementprecisionanduncertainty”onpage 133.
ThedisplayedMIandTIvaluesarebasedoncalculationsthatuseasetofacousticoutput
measurementsthatweremadeusingasinglereferenceultrasoundsystemwithasingle
referencetransducer
thatisrepresentativeofthepopulationoftransducersofthattype.The
referencesystemandtransducerarechosenfromasamplepopulationofsystemsand
transducerstakenfromearlyproductionunits,andtheyareselectedbasedonhavingan
acousticoutputthatisrepresentativeofthenominalexpectedacousticoutputfor
all
transducer/systemcombinationsthatmightoccur.Ofcourseeverytransducer/system
TEEx/8-3 MI No No No No
TIC, TIB, or TIS No No Yes Yes
Table 5: TI or MI 1.0 (Continued)
Transducer Model Index
2D/
MMode
CPD/
Color
PW
Doppler
CW
Doppler