Instrument Operations and Quality control Flashcards
With a matrix size of 64X64 and two sources placed 30 cm apart, there are 44 Pixels between the activity peaks on the generated activity profile. What is the pixel size?
a) 6.8cm/pixel
b) 6.8mm/pixel
c) 1.4mm/pixel
d) 0.14cm/pixel
b) 6.8mm/pixel
If the distance between two point sources placed on the camera surface is 35 cm in both the X and Y directions and the number of pixels between their activity profile peaks is 52 on the X-axis and 55 on the Y-axis, are the pixel dimensions in the X and Y direction within 0.5mm of one another?
a) Yes
b) No
a) Yes
Of the following types of transmission phantoms, which one requires the fewest images to test the spatial resolution over the entire detector face?
a) Hine-Duley phantom
b) Four-quadrant bar phantom
c) Parallel-line equal-space phantom
d) Orthogonal-hole phantom
d) Orthogonal-hole phantom
Select two reasons that metal implants in patients create problems for SPECT/CT and PET/CT systems.?
a) The additional weight of the patient may exceed the table’s load limit
b) High CT numbers from metal overestimate the attenuation that photons emitted by RPH will experience.
c) Artifacts in CT images due to the presence of metal may propagate to attenuation maps
d)Metal disturbs the magnetic field of CT
b) High CT numbers from metal overestimate the attenuation that photons emitted by RPH will experience
c) Artifacts in CT images due to the presence of metal may propagate to attenuation maps
What types of QC are usually done for Well counters?
a) Linearity
b) Consistency
c) Battery
d) Accuracy
e) Geometrie
f) Efficiency
g) Energy Resolution
a) Linearity
b) Consistency
c) Battery
d) Accuracy
e) Geometrie
What types of QC is usually done for Dose calibrators?
a) Consistency
b) Accuracy
c) Linearity
d) Geometrie
e) All of he above
e) All of he above
What types of QC are usually done for Survey meters?
a) Energy Peak
b) Background
c) Calibration
d) Energy Resolution
e) Efficiency
f) Consistency
a) Energy Peak
b) Background
c) Calibration
d) Energy Resolution
e) Efficiency
What types of QC are usually done for Uptake probes?
a) Linearity
b) Battery
c) Background
d) Consistency
b) Battery
c) Background
d) Consistency
The measurement on gamma camera is collected in which mode?
a) Pulse mode
b) Current mode
a) Pulse mode
Which measurement on an ionization meter and dose calibrator are collected in which mode?
a) Pulse mode
b) Current mode
b) Current mode
What is the smallest quantity a dose calibrator can accurately measure within +/= 5%?
a) 1mCi
b) 10uCi
c) 20uCi
d) 1uCi
c) 20uCi
What is the one reason the GM counter reading decrease as the distance decreases?
a) Dead time
b) Contamination of meter
c) Radiation has decayed away
d) Dead battery
a) Dead time
What is the probable cause for a low constancy reading on a dose calibrator?
a) Dead battery
b) Dead time
c) System zeroed with contamination present.
d) Source contaminated
c) System zeroed with contamination present.
The event in which each electron produces many ionizations and excites more gas particles, which in turn causes even more free electrons, is called what?
a) Geiger avalanche
b) Continous discharge
c) Townsend avalanche
d) Waterfall effect
c) Townsend avalanche
Which of these is NOT an example of a gas-filled detector?
a) Dose calibrator
b) Gamma camera
c) Ionization meter
d) Geiger counter
b) Gamma camera
Which of these is NOT an example of a scintillation detector?
a) Thyroid probe
b) Well counter
c) Dose calibrator
d) PET scanner
c) Dose calibrator
How is a scintillation detector better than a gas-filled detector?
a) Able to determine the energy of the gamma-ray
b) Can differentiate between different radionuclides
c) Can differentiate between unscattered and scattered gamma rays
d) All of the above
d) All of the above
What is the most common inorganic scintillator used in nuclear medicine?
a) NaI
b) BGO
c) Xe
d) NaCl
a) NaI
In which region does the dose calibrator operate?
a) Proportion region
b) Geiger-muller region
c) Ionization region
d) Continous discharge region
c) Ionization region
The higher the energy of the gamma-ray the more scintillation photons produced in a highly efficient scintillator.?
a) True
b) False
a) True
Which part of the detector converts the scintillation photons into an electrical signal?
a) NaI crystal
b) PMT tube
c) Preamplifier
d) Pulse height analyzer
b) PMT tube
What is energy resolution?
a) Ability to separate objects close in space
b) Ability to distinguish gamma rays close in energy
c) Ability to determine the exact energy of a gamma ray
d) Ability to see lines and spaces with the bar phantom
b) Ability to distinguish gamma rays close in energy
Well, counters and probe detectors usually come as a set. Why do you get different measurements of the same source?
a) Differences in geometry
b) One is a gas detector
c) Different calibration sources
d) Different crystal types
a) Differences in geometry
Which of the following collimators will magify an image?
a) Flat field
b) Diverging
c) Converging
d) High resolution
c) Converging
Which of the following must be performed every 6 months at a minimum?
a) COR
b) Sealed source leak test
c) Linearity of the dose calibrator
d) Area survey of hot lab
b) Sealed source leak test
The accuracy of a dose calibrator must be checked upon installation and then:
a) Monthly
b) Quarterly
c) Semiannually
d) Annually
d) Annually
What happens to image resolution as the distance between a patient and a parallel-hole collimator decreases?
a) Improves
b) Worsens
c) Does not change
a) Improves
What happens to the image size as the distance between a patient and a parallel-hole collimator decreases?
a) Increases
b) Decreases
c) Does not change
c) Does not change
What part of an imaging system emits light when it has absorbed a photon?
a) Photomultiplier Tube
b) Pulse height analyzer
c) Scintillation crystal
d) Collimator
c) Scintillation crystal
If two photons strike a sodium iodine crystal at the same time, what will occur?
a) Neither event will trigger production of light
b) The system will perceive only one event which will contain the summed energy of both photons
c) Both events will be correctly perceived
d) Only the photon closer to the center of the crystal will be perceived.
b) The system will perceive only one event which will contain the summed energy of both photons
The purpose of the pulse height analyzer is:
a) To minimize the amount of scattered radiation in the final image
b) To convert light into an electrical signal and to magnify that signal
c) To convert radioactivity into light
d) Th filter out photons which strike the crystal from oblique angles
a) To minimize the amount of scattered radiation in the final image
Which of the following can be measured in millimeters?
a) Energy resolution
b) Spatial resolution
c) Field uniformity
d) Temporal resolution
b) Spatial resolution
An orthogonal-hole phantom cannot be used to test spatial linearity since it does not contain lead bars.?
a) True
b) False
b) False
According to the curve for Cs-137 show in fig 1, what is the percent energy resolution of the system?
a) 6.9%
b) 8.2%
c) 10.5%
d) 11.8%
d) 11.8%
When using a 150uCi source of Tc99m to check uniformity, a tech measures the count in 1 minute as 53,125. If the background in the room is 405cpm, what is the sensitivity of the system?
a) 351cpm/uCi
b) 354cpm/uCi
c) 356cpm/uCi
d) 360cpm/uCi
a) 351cpm/uCi
What energies are included if a 20% symmetric window is used for the 364 KeV photopeak of I-131?
a) 191-437
b) 328-400
c) 337-391
d) 344-384
b) 328-400
Is SPECT imaging, if the image matrix size increased from 64X64 to 128X128, Which one of the following is true?
a) Total imaging time may need to be increased.
b) Spatial resolution will decrease
c) Image reconstruction will be faster
d) Image file size will decrease.
e) The count rate will decrease.
a) Total imaging time may need to be increased.
In PET Imaging, What is the outcome of imaging positrons with a long range of travel before undergoing annihilation?
a) Increased rate of random detection
b) Increase in streaking artifacts
c) Mispositioning where the radioactivity is located
d) Improved image resolution
b) Increase in streaking artifacts
