TH-A-16A-3
Image Quality Review II: Implementation of Image Quality Assurance
P Imbergamo*, 21st Century Oncology, Woonsocket, RI
1. The image of a Vegas phantom produces a contrast-detail curve where detail refers to:
a) Object density
b) Object location
c) Object size
d) Object contrast
e) Object spacing
Answer: c - Object size
Ref: Bushberg, “The Essential Physics of Medical Imaging”, 2nd edition, p287
2. High contrast or spatial resolution is measured using:
a) The Vegas phantom
b) A line pair test pattern
c) Isocenter cube or marker block
d) Only custom phantoms and software
e) Catphan uniformity & noise module
Answer: b - A line pair test pattern
Ref: Bushberg, “The Essential Physics of Medical Imaging”, 2nd edition, p273
3. Low contrast resolution:
a) Decreases with increasing SNR
b) Is unaffected by the noise in the image
c) Refers to objects that are close together
d) Is limited by the noise in an image
e) Is measured by a line pair test pattern
Answer: d - Limited by the noise in an image
Ref: Bushberg, “The Essential Physics of Medical Imaging”, 2nd edition, p280
4. %Noise in CT is:
a) Measured using the Leeds phantom
b) Measured using a H20 equivalent phantom
c) Measured by using the CT# of air & H20
d) Unrelated to the variation of CT# in an ROI
e) The same for all imaging techniques
Answer: b - Measured using a H20 equivalent phantom
Ref: Code of Federal Regulations: 21CFR1020.33
AAPM Report # 39, “Specification and Acceptance Testing of CT Scanners” p 29 -31
5. AAPM Report TG-142 for imaging:
a) Requires the use automated analysis software
b) Describes the tests procedures in detail
c) Addresses kV imaging only
d) Defines baseline data as minimally acceptable
e) Lists recommended tests, frequencies, and tolerances
Answer: e - Lists recommended tests, frequencies, and tolerances
Ref: Table VI, “Task Group 142 report: Quality assurance of medical accelerators,” Med. Phys. 36 (9) September 2009
rev: 6/1/14