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PET Study Guide > chapter 4: pet instrumentation > Flashcards

chapter 4: pet instrumentation Flashcards

1
Q

setting the ring plane difference to limit the number of contiguous rings that allow coincidence detection may

reduce the wide variation in sensitivity

reduce the wide variation in specificity

decrease the number of detected randoms

increase the number of detected trues

A

reduce the wide variation in sensitivity

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2
Q

the energy resolution of crystal materials used in pet scanners is relatively

high
poor
variable
different depending on the material

A

poor

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3
Q

the dominant type of interaction at 511 kev is

characteristic
bremsstrahlung
compton scattering
photoelectric

A

compton scattering

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4
Q

scatter fraction is dependent on all of the following except

energy window
signal to noise ratio
scatter material geometry and size
specifics of the scanner

A

signal to noise ratio

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5
Q

NECR =

A

T^2/(T+S+R)

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6
Q

detector parallax can be described as

a scanner having too few detectors, decreasing sensitivity

the increase in randoms and scatters in 3d mode

interactions taking place at varying crystal depths at the edge of the FOV

mispositioned LORs

A

interactions taking place at varying crystal depths at the edge of the FOV

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7
Q

when applying a PSF correction, this may affect

scanner sensitivity
SUVs
NECR
signal-to-noise ratio

A

SUVs

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8
Q

acquiring in list mode is available and advantageous for all of the following except

ToF systems
cardiac gating
respiratory gating
2D mode

A

2D mode

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9
Q

the use of timing marker information and physiologic gating markers describes

frame mode
list mode
A and B
cardiac gating

A

list mode

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10
Q

pyramidal sensitivity is most commonly an issue with

overlapping bed positions
continuous bed motion
ToF systems
patients with large body habitus

A

overlapping bed positions

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11
Q

all of the following contribute to the high-quality image except

Tof acquisition
overlapping bed positions
applying PSF correction
scatter/random fraction correction

A

overlapping bed positions (continuous is better, more uniform sensitivity)

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12
Q

which is the correct order after image acquisition?

raw data formed into sinograms, recon to axial image slices, apply corrections

raw data formed to sinograms, apply corrections, recon to axial image slices

apply corrections, raw data formed to sinograms, recon to axial image slices

apply corrections, recon to axial image slices, raw data formed to sinograms

A

raw data formed into sinograms, recon to axial image slices, apply corrections

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13
Q

the most commonly used recon algorithm in pet is

FBP
RAMLA
OSEM
MLEM

A

OSEM

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14
Q

the typical parameters for reconstructing a pet scan are usually

high number of subsets and high number of iterations

low number of subsets and low number of iterations

low number of subsets and high number of iterations

high number of subsets and low number of iterations

A

low number of subsets and high number of iterations

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15
Q

all of the following are methods to reconstruct 3D angle sinograms except

SSRB
FORE
RAMLA
full 3D recon

A

RAMLA

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16
Q

the most common filter used for pet images is the

butterworth filter
gaussian filter
3d filter
scatter fraction filter

A

gaussian filter

16
Q

the most common technique for processing 3D sinograms is

FORE
SSRB
full 3d recon
RAMLA

A

FORE

17
Q

a very smooth pet scan image will most likely have a filter applied that is

5 mm
7 mm
10 mm
12 mm

A

12 mm

18
Q

pet scanners are inherently what type of image?

qualitative
quantitative
3d
2d

A

quantitative

19
Q

one issue with applying a PSF correction is

SUVmax is falsely lower
SUVmax is falsely higher
SUVmin is falsely lower
SUVmin is falsely higher

A

SUVmax is falsely higher

20
Q

a bright rim of activity around the outside edge of the body indicates

truncation
non-attenuated photons
high voltage drift
low signal-to-noise ratio

A

non-attenuated photons

21
Q

the mathematical assumption of uniform attenuation is referred to as the

chi square test
chang technique
point spread function
iterative reconstruction

A

chang technique

22
Q

the technique that assumes that the linear attenuation coefficient is the same for all pixels may be used in all of the following areas except the

brain
chest
abdomen
pelvis

A

chest

23
Q

transmission sources are most commonly

Cs137 and Ba133
Cs137 and Ge68
Ge68 only
Cs137 only

A

Cs137 and Ge68

24
Q

Ge68 is a

beta emitter
alpha emitter
positron emitter
positron and beta emitter

A

positron emitter

25
Q

all of the following are true concerning transmission scans for attenuation correction except

has lower radiation exposure compared to CT

transmission image must be transcribed to 511 keV values

takes 20-30 mins

Ge68 or Cs137 may be used

A

transmission image must be transcribed to 511 keV values

26
Q

image segmentation refers to

the recon of 3d slices to 2d slices

identifying areas that have similar tissue density

the transcribing of CT data to 511 keV attenuation values

the mathematical assumption of attenuation values

A

identifying areas that have similar tissue density

27
Q

replacing pixel values

increases image noise
reduces image noise
prolongs reconstruction
shortens reconstruction

A

reduces image noise

28
Q

the scanner measures image radioactivity in

MBq/ml
KBq/ml
mCi/ml
uCi/ml

A

KBq/ml

29
Q

SUVbw =

A

roi tracer concentration (mCi/cc) / (tracer dose (mCi)/patient weight (kg))

PET Study Guide (19 decks)

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