Quality Assurance

Question 1

Quality Assurance

Answer 1

Routine, periodic evaluation of an ultrasound system to guarantee optimal image quality

Question 2

Requirements

Answer 2

1. Assessment of system components
2. Repairs
3. Preventative maintenance
4. Record keeping

Question 3

Goals

Answer 3

1. Guarantee proper operation
2. Detect gradual changes
3. Minimize downtime
4. Reduce the number of non-diagnostic exams
5. Reduce the number of repeat songs

Question 4

Devices

Answer 4

1. tissue equivalent phantom
2. Doppler phantom
3. beam profile/slice thickness phantom

Question 5

Methods

Answer 5

1. Known, defined conditions
2. Constant instrument settings
3. Phantom w/ measurable characteristics
4. Image in identical environment

Question 6

Objective vs. Subjective

Answer 6

Objective: Unbiased
Subjective: Influenced by experience/beliefs

Question 7

Tissue Equivalent Phantom

Answer 7

Similar to soft tissue in speed of sound, attenuation, scattering, & echogenicity; contain structures that mimic cysts

Question 8

Doppler Phantom

Answer 8

Assess all characteristics of Doppler modalities (i.e. pulsed, continuous wave, color mode, power mode)
Include circulation pumps, vibrating strings, moving belts, flow phantoms

Question 9

Slice Thickness Phantom

Answer 9

Contains scattering plane that is at an angle to the incident sound beam
Important b/c slice thickness is most likely to degrade image quality

Question 10

Normal Sensitivity

Answer 10

All pins, solid masses, and cystic structures are accurately displayed; power, TGC, and amplification are adjusted to establish normal sensitivity

Question 11

Maximum Sensitivity

Answer 11

Power & amplification set to maximum levels & depth is measured

Question 12

Dead Zone

Answer 12

Region close to the transducer where images are inaccurate

Question 13

Frequency & Dead Zone Relationship

Answer 13

Higher freq. = thinner dead zone

Question 14

Cause of Dead Zone

Answer 14

Results from transducer ringing & duration it takes to switch between transmit & receive mode

Question 15

Causes of Deep Dead Zones

Answer 15

Cracked crystal, detached backing material, longer pulse duration

Question 16

Registration Accuracy

Answer 16

Ability of system to place reflections in proper positions while imaging from different orientations

Question 17

Depth Calibration

Answer 17

Accuracy of reflector depth positioning in A-Mode, B-Mode, M-Mode, and 2D imaging

Question 18

Horizontal Calibration

Answer 18

Systems ability to place echoes in their correct position when reflectors are perpendicular to the sound beam

Question 19

Distance Measurement Accuracy

Answer 19

Measured by digital calipers in vertical and horizontal directions

Question 20

Axial Resolution evaluated by

Answer 20

Scanning sets of closely spaced pins in phantom

Question 21

Lateral Resolution evaluated by

Answer 21

Measuring width of reflections (estimates beam diameter)

Question 22

Display evaluated by

Answer 22

Compare image on screen to other display devices