Transcript Chapter 19/20

Chapter 19 Screen-Film
Image Artifacts
• Usually TECHNOLOGIST dependant
• Patient Preparation
– Clothes left on (zippers, jewelry, dentures
– Positioning errors (patient, tube, bucky, receptor)
– Wrong screen-film combination (detail screens
with fast film and vice-versa)
– “Bling” left on
Processing Artifacts
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Roller marks; guide shoe lines, Pi lines
Dirty rollers (curtain effect/run down, etc.)
Chemical fog
Wet-pressure sensitization (varied amount of
pressure on the rollers = uneven film
“splotches”)
Handling Artifacts
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Light/radiation fog
Kink marks
Static (tree, smudge are the most common)
Hypo retention (fixer retention – required for
mammo)
Chapter 20 Film-Screen Quality Control
• Quality Assurance is a JCAHO required 10 step
PEOPLE PROCESS!
• Quality Control = imaging instrumentation and
equipment process
QC = 3 step process
• Acceptance testing
• Routine performance monitoring
• Maintenance
Radiography QC
• Filtration – annually
• Collimation – semiannually (+/- 2% SID)
• F.S. size – Annually (+/-50%) FREQUENTLY
MISSED PARAMETER!
• kVp calibration – Annually (+/- 10%)
• Exp. Timer accuracy – annually (based on mS
used – more leeway with longer exposures)
• Linearity – annually (+/- 10%) of same mAs with
DIFFERING mA/times
• Exp. REPRODUCEIBILITY – SAME contrast/density,
etc with SAME exp. factors repeated later on
Focal Spot Size Check Tools
• Pin hole camera (somewhat hard to use?)
• Star pattern (down to .3mm sizes)
• Slit camera – preferred method
Other RAD QC
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Filtration
Collimation (PBL)
kVp/Timer
Exposure Linearity (same mAs with VARIED
mA and times)
• Intensifying screens
• Protective apparel (annually)
• Film illuminators
Fluoro QC
• Exposure rate (max table top dose/min)
• Spot film exposures
• Automatic Exposure System (ABS/ABC – AEC)
Tomo QC
• Tube travel/ ARC
• Fulcrum level
• Patient exposure
Processor QC
• See Table 20-6 for QC RAD Processor
items/intervals
• Processor Maintenance
– Scheduled maintenance
– Preventative maintenance
– Nonscheduled maintenance
Processor Monitoring
• Temperatures
• Replenishment
• Sensitometry/Densitometry