Flashcards in Chapter 22 Deck (24):
What is quality assurance?
the routine, periodic evaluation of an ultrasound system to guarantee optimal image quality
When should quality assurance be performed?
routinely and periodically
What are the four requirements for a quality assurance program?
1. assessment of system components
3. preventive maintenance
4. record keeping
What are the five goals of quality assurance program?
1. guarantee proper operation of the system
2. detect gradual changes
3. minimize downtime
4. reduce the number of non-diagnostic exams
5. reduce the number of repeat scans
What are devices that enable the sonographer to perform quality assurance?
1. tissue equivalent phantom
2. Doppler phantom
3. beam profile/slick thickness phantom
What are the proper methods for quality assurance?
1. test under know, defined conditions
2. use constant instrument settings
3. use a phantom with measurable characteristics
4. image in an identical environment
What are objective info?
factual, repeatable, and able to be counted
Used for quality assurance programs
In what ways are tissue equivalent phantom similar to soft tissue?
speed of soft tissue
What is evaluated with tissue equivalent phanotom?
gray scale and tissue texture, also multi-focus and adjustable focus phased arrays
What do Doppler phantoms include?
true or false: Doppler phantoms assess pulse, CW, color and power mode?
What does slice thickness determine?
When is sensitivity assessed?
when the sonographer adjusts the system controls to change echo brightness from barely visible to full brightness
What are normal sensitivity setting?
are those at which all the pins, solid masses, and cystic structures in the test phantom are accurately displayed
Where is the dead zone?
is the region close to the transducer where images are inaccurate
Which transducer have a thinner dead zone?
higher freq transducers
What is vertical depth calibration?
describes the systems accuracy in placing reflectors at correct depths located parallel to the sound beam
What are horizontal calibrations?
the systems ability to place echoes in their correct position when the reflectors are perpendicular to the sound beam
What is depth calibration?
the accuracy of reflector depth positioning in A mode, M mode, and B-mode and 2D imaging
What is axial resolution in quality assurance?
the smallest distance at which two pins positioned parallel to the sound beam are displayed as two distinct echoes
scanning sets of successively closer spaced pins within the phantom
What is lateral resolution in phantoms?
min distance at which two side by side pins are displayed as two distinct images
What is another way to evaluate lateral resolution?
is to measure the width of reflections on the display that are created by point targets in the phantom
What is uniformity?
the systems ability to display similar reflectors in the phantom with echoes of equal brightness.