Chapter 22 Quality Assurance Flashcards
Quality assurance is important because
It validates the consistency of images and the accuracy of devices
Quality assurance is
The routine periodic evaluation of the system to guarantee optimal image quality
What are the 4 quality assurance requirements
Repairs, Assessment of system components, Preventative maintenance, Record keeping
Q.A. Goals
Proper operation of equipment, detect changes in performance, minimize downtime, reduce the # of non-diagnostic exams
Q.A. Devices
Tissue equivalent phantom, Doppler phantom, Beam profile/ slice thickness phantom
Q.A. is based on Objective Standards:
unbiased, factual, repeatable
Tissue Equivalent Phantom involves
box filled with medium with same PS speed and attenuates, scatters and present echogenicities similar to soft tissue
embedded in tissue equivalent phantom are
pins, mock cysts masses
the T.E. phantom is used to take performance measurements and to
evaluated grayscale/tissue texture
Doppler or Flow Phantoms are used to
evaluate Doppler systems
Modern Doppler Phantoms include
circulation pumps which propel fluid through vessels embedded in the tissue equivalent phantom
Other Doppler phantoms contain
vibrating strings or moving belts
Doppler phantoms assess characteristics of
all doppler modalities including PW, CW, color, and power mode
Slice Thickness Phantom is used to
specifically to evaluate slice thickness which determines elevational resolution
elevational resolution is most likely to degrade because
the imaging plane is thicker than either the beam width or pulse length
if the slice is not thin,
low contrast lesions can not be seen or cystic structures may appear filled in
A scattering plane in an anechioc medium is imaged at either ____ or ____ degree angle
45 or 90
The display of a Slice Thickness Phantom demonstrates
the beam geometry or thickness
Phantoms are used to
take performance measurements
Tissue Equivalent Phantom allow personnel to record
performance measurements
Performance measurement: Sensitivity is the ability of
the system to register low level echoes ( 2 levels are assessed – normal and maximum)
(performance measurement) normal sensitivity is the
gain, TGC, and power – where pins, cysts and masses are accurately displayed
(performance measurement) maximum sensitivity is evaluated by
setting the power and amplification to maximum and determining the maximum depth of tissue
(performance measurement) Dead zone
the region close to the probe where images are absent due to the time it takes to switch from transmit to receive
