Ch 22 - Quality Assurance

Quality Assurance (QA) = _____ of US to guarantee optimal image quality

eval

US should be based on _____ standards

objective

Objective = _____ = Factual = always the ____regardless

unbiased, same

Subjective = ____ by experience/belief = affected by _____ = ____ from person to person

influenced, opinion, varies

What 3 people inspect US machines

medical physicist, biomed engineer, US vendors

What are the 4 REQUIREMNETS for QA

1. asses sys ____

2. _____

3. ______ maintenance

4. _____ keeping

components, repairs, preventative, record

What are the 5 GOALS of QA?

1. guarantee proper ____ of sys

2. detect ____ changes

3. ______ downtime

4. _____ # of non-diagnostic exams

5. reduce # of _____ exams

operation, gradual, min, reduce, repeat

The 3 devices used to perform a QA are the ____ equivalent phantom, ____ phantom, ___ ___/ ____ ____ phantom

Tissue, Doppler, Beam Profile/Slice Thickness

Tissue Phantom is used to eval ____ ___ imaging, _____ texture and _____ focus phased arrays

grey scale, tissue, multi

What are the 3 types of Doppler Phantoms

vibrating string, moving belt, flow phantom

The _____ _____ phantom determines the elevational + lateral resolution

slice thickness

Sensitivity = ability of sys to eval ____ lvl echoes

low

_____ sensitivity = all pins/solid/cystic struct in phantom on display and do NOT vary from 1 eval to another

normal

_____ sensitivity = output power/amp is set to max

Maximum

The ____ ____ is the area closet to the transducer where images are _____

Dead Zone, inaccurate

_____ freq transducers have a THINNER dead zone vs _____ freq transducer

higher, lower

A ______ ___ is useful to eliminate the dead zone

Standoff pad

Registration Accuracy = ability for sys to place reflectors in ____ ____

proper positions

_____ accuracy = placing reflectors at correct DEPTHS parallel to sound beam

Range

Horizontal Calibration = placing reflectors at correct position ______ to sound beam

perpendicular

_____ ______ Accuracy is imp in follow up/repeat exam w/ measurement

Distance Measurement

Focus = depth where beam is ______, Focal Zone = ____ the focus

narrowest, surrounds

Axial Resolution is determined by the ____ ____

pulse length

Axial Resolution = ability to tell apart objects that are ____ to the sound beam

parallel

_____ Pulses = improved axial res

shorter

Lateral Resolution is determined by the _____ _____

beam width

Lateral res = ______ _____

beam diameter

Lateral Resolution = ability to tell apart objects that are ____ or ____ ___ ___ to the sound beam

perpendicular, side by side

_____ is in reference to the ENTIRE image + eval if identical reflectors are the same brightness at diff depth

Uniformity

Display = _____/_____ of the monitor

brightness/contrast