Chapter 19 Screen-FilmImage 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

• 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

• 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

• 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