Detector Efficiency
System Resolution
Dose Calibrator QC
Gamma Camera QC
Detector Components
PET Stuff
100
The ratio of the number of detected events to the number of available events to be detected.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is C. Detector efficiency
100
This is advantageous in photon detection because it allows the discrimination of photoelectric events from scattered events.
A. Temporal Resolution
B. Energy Resolution
C. Spatial Resolution
What is energy resolution?
100
This is used to verify that the dose calibrator is measuring radioactivity precisely.
A. Linearity Test
B. Accuracy Test
C. Constancy Test
D. Geometry Test
What is constancy test? done daily.
100
True or False.
Collimators can stay on for extrinsic uniformity QC
True
100
Name the electronic components of a gamma camera that are required to produce and analyze the event pulses. (100 points for each answer)
Photon transducer (PMT), a preamplifier, amplifier, pulse height analyzer, scalars, or rate meters
100
Name a PET detector (4 answers)
BGO, LSO, LYSO, GSO
200
The fraction of the radiation emitted by a source that is intersected by the detector.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is B. Geometric Efficiency
200
The precise time determination of when an event has occurred.
A. Temporal Resolution
B. Energy Resolution
C. Spatial Resolution
What is temporal resolution?
200
This test checks that the calibrator is able to accurately assay over the entire range of radioactivity used in the laboratory.
A. Linearity Test
B. Accuracy Test
C. Constancy Test
D. Geometry Test
What is Linearity Test? Done quarterly.
200
Name one way to do spatial resolution QC (Two answers)
Bar Pattern or SPECT Phantom
200
Converts visible light into an electronic pulse.
Photomultiplier tube
200
PET projections are obtained from ______ lines of response.
Coincidence
300
The fraction of radiation that is detected when it is intersected by the detector.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is A. Intrinsic efficiency?
300
FMHM (KeV) / Photon Energy (KeV) X 100%
A. Temporal Resolution
B. Energy Resolution
C. Spatial Resolution
What is equation for Energy Resolution?
300
The ______ of the dose calibrator must be validated annually using calibrated radioactive sources traceable to the NIST.
A. Linearity Test
B. Accuracy Test
C. Constancy Test
D. Geometry Test
What is the accuracy test?
300
DAILY DOUBLE
What is the problem with the picture on the left regarding QC.
Photopeak setting Problem. Study on the left is using Co-57 peak and not Tc-99m
300
This type of collimator is generally avoided because they have the lowest sensitivity of any collimator design for a given spatial resolution.
What is a diverging colimator?
300
Falsely hot activity on body surfaces and falsely low activity within deep structures is demonstrated without what type of correction?
Attenuation Correction
400
For detectors that retain energy information about the radiation, detected events may be accepted or not depending on where they fall within an energy range.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is D. Photopeak Efficiency?
400
DAILY DOUBLE
When an event happens too rapidly, it cannot be properly analyzed, and information is lost.
What is Deadtime?
400
This checks to determine whether activity measurements change with sample volume or configuration.
A. Linearity Test
B. Accuracy Test
C. Constancy Test
D. Geometry Test
What is geometry test?
400
What would pictures look like if the PMTs have gone bad?
False Cold Spots
400
Name the 5 types of collimators. (All or Nothing)
Parallel hole, fan beam, converging, diverging, pinhole
400
A display technique that uses reprojections of the volume information back into a series of projections around the body is called?
A MIP, maximum-intensity projection
500
This is improved when the detector area is large or the source is close to the detector.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is Geometric Efficiency?
500
This describes the ability of an imaging system to display detail.
A. Temporal Resolution
B. Energy Resolution
C. Spatial Resolution
What is Spatial Resolution?
500
What are the two methods that are used to evaluate linearity.
The decay of a test source or by attenuation shields.
500
Name an annual test we do on Gamma Cameras
(5 answers)
High Count Uniformity, Energy Resolution, Count Sensitivity, Count Rate Performance, Multiwindow Spatial Registration
500
You're imaging a tiny baby's kidneys and zoom isn't an option for your parallel hole collimator, what collimator would be best for this study?
Converging collimator.
500
What's a disadvantage to filtered back-projections
Created severe streak or star artifacts, thus increasing image noise and reducing contrast.
600
This is affected by the composition and size of the radiation detector.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is Photopeak Efficiency?
600
Low spatial frequencies tend to be recorded accurately whereas high spatial frequencies are ________.
A. Attenuated
B. Absorbed
What is Attenuated?
600
What should be used if any of the measured activities exceed a 10% error from the expected activity? (Part of geometry testing)
A correction factor.
600
Characterized by a large number of hot spots at the periphery of the field of view.
What is Crystal Hydration (Measles)
600
Name 2 parameters that determine collimator sensitivity (total of 4 answers)
Hole length, hole diameter, hole geometry, septal thickness
600
What QC scan must be done each morning to be used as a reference uniformity measure for the transmission scan used in attenuation correction.
Blank Scan
700
Detectors based on gases, where the density of atoms is low, typically have very low ______.
A. Intrinsic efficiency
B. Geometric efficiency
C. Detector efficiency
D. Photopeak Efficiency
What is intrinsic efficiency?
700
The blurring effect of spatial resolution.
What is convolution?
700
What sources are used for accuracy test?
Co-57, Ba-133, Cs-137, Ge-68
700
What are the three Accreditation Organizations (2/3 for points)
Joint Commission, ACR, IAC
700
Name 3 parameters that determine collimator spatial resolution. (All or nothing)
Hole length, hole diameter, the distance between source and collimator
700
What is the purpose of a transmission scan, and how can it be done? (double points by answering both questions)
To provide attenuation correction by using an external rotating radioactive source (Ge-68) or by a low-dose CT.