Chapter 19 Screen-Film

unkindnesskindUrban and Civil

Nov 15, 2013 (3 years and 11 months ago)

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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


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.
f
actors 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