Physics QA Flashcards

1
Q

Who directs the QA program?

A

Physician

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2
Q

Who assesses quality of images?

A

Radiologist

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3
Q

Who are the 2 types of service personnel?

A

Manufacturer and biomedical personnel

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4
Q

What does the manufacturer do?

A

Preventative maintenance and repair equipment

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5
Q

What does the biomedical personnel do?

A

Acceptance testing when machine arrives on site to ensure safety.

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6
Q

What is acceptance testing?

A

Sophisticated testing before machines are operated.

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7
Q

What can a phantom assess?

A

Resolution, sensitivity, accuracy, etc

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8
Q

What is the key component to a good QA program?

A

Record keeping

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9
Q

How many times are is the accuracy checked in a year?

A

2-3 times under warrranty.

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10
Q

What is the AIUM 100?

A

Older testing device, encased in plastic case that contains 0.75mm steel rods arranged in groups and filled with water, 9% alcohol and algaecide

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11
Q

Why are AIUM 100’s not used?

A

No greyscale and do not attenuate.

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12
Q

What are the films made of on the tissue phantoms?

A

Saran or polyurethane

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13
Q

What are the containers made of?

A

ABS, PVC or acrylic

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14
Q

How is a “good” phantom characterized?

A

Attenuation coefficient, speed of sound, back scatter coefficient, elasticity, thermal properties

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15
Q

What can phantoms test?

A

Dead zone, detailed res, distance accuracy, image uniformity, depth of pen, cyst imaging capabilities

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16
Q

Describe the dead zone

A

Area in near field close to transducer (AKA: main bang)

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17
Q

What is an acceptable dead zone measurement?

A

15mm

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18
Q

When can the dead zone be very larger?

A

Old mechanical probes

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19
Q

Ability to separate interfaces along the path of the beam?

A

Testing axial resolution

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20
Q

Ability to separate interfaces across the beam?

A

Testing lateral resolution - measuring pins

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21
Q

What is lateral res dependant on?

A

Depth and focus

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22
Q

What test requires a different type of phantom?

A

Elevation resolution/slice thickness

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23
Q

What kind of phantom is used for elevational testing?

A

Spherical void phantom or beam profile phantom

24
Q

Is elevational resolution qualitative or quantitative?

A

Quantitative

25
Q

How can we detect margins of error?

A

Measure over larger distances to detect small errors

26
Q

What does it mean when we see a dark vertical band?

A

Usually a broken crystal

27
Q

What does sensitivity test?

A

Ability to detect weak echoes

- increase depth until it darkens

28
Q

What is dynamic range?

A

Number of shades of grey (contrast)

29
Q

How can we determine capability of dynamic range?

A

Compare images over time/ compare to previous records

30
Q

Contrast resolution

A

Ability to distinguish between simulated lesions of similar echogenicity

31
Q

What does contrast res detect?

A

Difference in appearances of solid, cystic, echogenic, hypoechoic lesions

32
Q

When is registration tested?

A

Tested on older static B scanners to ensure arm positioning is accurate to reconstruct an image

33
Q

What does registration look like?

A

Scanning pins from 3 different sides to see if lines intersect at one point

34
Q

What are the different types of Doppler phantoms?

A

Flow & String/belt

35
Q

What is a flow Doppler phantom?

A

Match clinical experience - expensive

36
Q

What are string phantoms?

A

Move string or belt in water belt and are affordable

37
Q

What do flow phantoms measure?

A
Max depth
Gate position accuracy
Volume flow & velocity accuracy
Colour flow penetration
Image congruency test
38
Q

What else can phantoms be used for?

A

Demonstration, training, research & development

39
Q

Hydrophone

A

Measure aspects of our beam technical parameters

Produces a voltage proportional to received acoustic pressure wave

40
Q

Output testing devices

A

Hydrophone, power balances, calorimeter

41
Q

What can a hydrophone measure with an oscilloscope?

A
SPL
PD
PRP
PRF
DF
42
Q

What can a hydrophone measure with a spectrum analyzer?

A

Resonant (f), bandwidth, Q factor

43
Q

What does a force balance measure?

A

Acoustic power

44
Q

Calorimeter

A

“Heat meter” used to measure acoustic power (thermocouple)

- amount of heat produced determines power that is being produced

45
Q

What is being tested when scanning in axial resolution?

A

Reverberation

46
Q

What is added to a hydrophone to measure fractional bandwidth?

A

Spectrum analyzer

47
Q

What is considered a “good” tissue equivalent phantom?

A

One half the frequency times the path length

48
Q

Who is responsible for semi-annual maintenance?

A

Manufacturer

49
Q

What uses a sound absorbing block and sophisticated scale to measure acoustic power and intensity?

A

Force balance

50
Q

What test is performed with a Doppler phantom ensure that colour flow is displayed accurately on the screen?

A

Image congruency

51
Q

What is the AIUM 100 test object used to assess?

A

Dead zone

52
Q

What is the systems best axial resolution based on?

A

Greatest separation between pins (2mm)

53
Q

Who is the leader to carry out QA performance testing?

A

Radiologist & sonographer

54
Q

Role of manufacturer

A

Routine preventative maintenance and repair

55
Q

Role of biomedical personnel

A

Acceptance testing

56
Q

How are pins configured in phantoms?

A

“J” configuration - compensates for reverb artifact

57
Q

What group of pins is used to assess the lateral resolution?

A

Vertical group - will show beam width related to point spreading at various depths