Quality Assurance

Question 1

What is quality assurance?

Answer 1

• It is the routine or periodic evaluation of an ultrasound system that occurs to ensure that optimal image quality can be attained

Question 2

What are quality assurance requirements?

Answer 2

• System component assessment
• Repairs
• Preventative maintenance
• Record keeping

Question 3

What are the goals of quality assurance?

Answer 3

• Guarantee of proper system operation
• Detect gradual changes
• Minimize downtime
• Reduce non-diagnostic exam number
• Reduce repeat scan number

Question 4

What methods are used to conduct quality assurance?

Answer 4

• Testing under known and defined conditions
• Using constant instrument settings
• Using a phantom with characteristics that are measurable
• Imaging in identical environment

Question 5

What is an objective standard?

Answer 5

• A standard that is completely unbiased and unaffected by an individual’s preference, opinions, or experiences
• It is factual, repeatable, and can be counted

Question 6

What is a subjective standard?

Answer 6

• A standard that is influenced by someone’s opinions or experiences
• It cannot be verified by with concrete facts and figures

Question 7

What kind of standard is a phantom?

Answer 7

Objective

Question 8

What is a tissue-equivalent phantom? In what ways is it similar to soft tissue?

Answer 8

• It is a phantom with ultrasound features similar to those in soft tissue and are used to evaluate characteristics like gray scale, tissue texture, and focus.
• It is similar to soft tissue:
  • Speed of sound
  • Attenuation
  • Scattering characteristics
  • Echogenicity

Question 9

What Doppler modalities can be assessed with a Doppler phantom?

Answer 9

• It can assess pulsed, continuous wave, color, and power mode.

Question 10

What are three different types of Doppler phantoms?

Answer 10

• The three types of doppler phantoms are vibrating string, moving belt, and flow phantom

Question 11

What does a slice thickness phantom evaluate?

Answer 11

• It evaluates slice thickness and the effect is has on image accuracy
• Slice thickness is most likely to degrade image quality

Question 12

What is normal sensitivity?

Answer 12

• Those at which all pins, solid masses, and cystic structures from the phantom are accurately displayed
• The output power, TGC, and amplifications are adjusted

Question 13

What is Maximum Sensitivity?

Answer 13

• A tissue equivalent is images and depth of the tissue texture is measured with output power and amplification at maximum practical levels.
• Used to assess sensitivity and should not differ

Question 14

What is the dead zone? Which pins in the phantom are sued to measure the dead zone?

Answer 14

• The dead zone is the area close to the transducer where accurate images are found. It extends from the transducer to the shallowest depth where meaningful images appear.
• The pins in the phantom that are used to measure the dead zone are the shallowest pins, which should be those from the near field in this image

Question 15

What does range accuracy evaluate?

Answer 15

• Range accuracy evaluates the system’s accuracy in placing reflectors at correct depths when parallel to the sound beam

Question 16

What is Horizontal calibration?

Answer 16

• It is the ability of the system to place echoes correctly when reflectors are perpendicular to the sound beam

Question 17

What is the focal zone?

Answer 17

• The depth where the intensity is the highest while the beam is the narrowest.
• It has excellent lateral resolution

Question 18

What is axial resolution? Which pins are sued to measure axial resolution?

Answer 18

• The smallest distance where two pins parallel to the sound beam are displayed as two distinct echoes
• The pins used to measure axial resolution are parallel to the sound beam and labelled axial resolution on the diagram.

Question 19

19. What is lateral resolution? Which pins can be sued to measure lateral resolution?

Answer 19

• The smallest distance at which two side by side pins can be seen as two distinct echoes
• The pins used are those perpendicular to the sound beam