TG-66 Memorizing information Flashcards
How often do you measure CT number accuracy?
Daily for CT number of water only
Monthly for 4 to 5 difference materials
Annually for a electron density phantom
Tolerance for daily CT number accuracy
0 +- 5 HU
How often do you measure image noise?
Daily
In-plane spatial integrity tolerance
1 mm
How often do you measure in-plane spatial integrity?
Daily for x or y direction
Monthly for both directions
When do you measure field uniformity and for what kVp settings?
Monthly - most commonly used kVp
Annually - other used kVp settings
What kVp’s do we use in our clinic?
140 kVp for everything
Why do we only use 1 kVp setting for all scans?
So we don’t need multiple HU maps for eclipse
Field uniformity tolerance
Within +- 5 HU
When are you supposed to measure spatial and contrast resolution?
Annually, but we do it monthly as well
Tolerance for spatial and contrast resolution
Vendor specification +- 1 visible node on catphan
How often should you measure CT slice width?
Monthly
Frequency of patient dose from CT-scan, CTDI measurement
Annually
Frequency of table movement and positioning tests
Monthly
Frequency of artifact evaluation
Monthly