Transcript QUALITY CONTROL - Oregon Institute of Technology

QUALITY CONTROL
For the Technologist
TECHNOLOGIST RESPONSIBILITIES
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DAILY
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Darkroom Cleanliness
Sensitometry
WEEKLY
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Screen Cleanliness
Viewbox cleanliness
Phantom Imaging
MONTHLY
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Visual Checklist
QUARTERLY
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Repeat/Reject Analysis
Fixer Retention
SEMIANNUALLY
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Compression
Film/Screen Contact
Darkroom Fog
DARKROOM CLEANLINESS
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NEVER:
 Carpet
a darkroom
 Store boxes or cartons and never open
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ALWAYS:
 Have
shelving with doors
 Replace filters and service air conditioning
 Wipe countertops with damp cloth
 Wipe film trays with anti-static solution
 Use a black light
SENSITOMETRY
Must use same box of film
 Must be performed before clinical films
 Check Developer temperature
 Flash sensitometric strip on emulsion side
 Speed and Contrast Index within +/-.15
 B+F within +/-.03
 Developer within +/-.5 degrees
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SENSITOMETRY
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When data falls outside of the limits
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Trends
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Documentation
SCREEN CLEANLINESS
Clean when 3-4 specks shown
 Use Antistatic solution
 4x4 rayon or lintless 100% cotton pads
 Wipe in circular motion from center out
 Let dry
 Use one of many tools available to get rid
of dust
 Check with black light
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VIEWBOXES
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Clean weekly to remove dust, smudges,
etc
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Change bulbs every 12-18months
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Test luminance with light meter (not
required by MQSA)
PHANTOM IMAGING
Monitors whole system
 Simulates a 4.5 cm compressed breast
 Consists of 6 nylon fibers, 5 oxide specks,
5 tumor masses
 Should be performed:
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 After
any service
 After changes in chemistry or film
 Whenever changes in image quality suspected
PHANTOM PROCEDURE
AEC placed same as a 4.5 cm breast
 4mm acrylic disc placed away from objects
 Background density: center, 1.2 OD +/-.2
 Density difference: .4 +/-.05 for films at
28kVp
 Chart mAs to evaluate reproducibility
(should not vary more than +/-.15)
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PHANTOM ANALYSIS
Must see 4 fibers, 3 specks, 3 masses (10)
 Can vary +/-1 but no lower than 10
objects.
 Viewed:
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 By
same person
 Same time of day
 On same viewbox
 Under same viewing conditions
 Using same type of magnifying lens
VISUAL CHECKLIST
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Takes inventory of room to ensure safety,
comfort and convenience
FIXER RETENTION
Performed right after daily strip on
emulsion side in clear area
 Place drop of fixer and let sit 2 minutes
(do not expose to bright light)
 Blot dry and place on white cardboard
 Compare to chart. No more than 5ug/cm
squared (3 on the chart)
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REASONS FOR ELEVATED FIXER
Inadequate wash water flow rate
 Partially depleted fixer (enough activity for
clearing but not enough for hardening)
 Insufficiently hardened emulsion retains
too much fixer for wash to remove.
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RESULT: Degrades stability of image
FIXER CORRECTION
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Increase fixer replenishment
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Increase water flow
REPEAT/REJECT ANALYSIS
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To evaluate reasons films are repeated
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Points out insufficiencies, waste
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Can improve efficiency
REPEAT ANALYSIS PROCEDURE
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Quarterly and at least 250 patients
examined
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Films are categorized
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ACR states number of repeats should be
no greater than 5%.
WAKE UP!
ITS OVER!
COMPRESSION
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Image quality and safety test
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Test in both power drive and manual
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MQSA states 25 – 47 lb range
How does compression improve
quality?
Decrease scatter
 Decrease dose
 Decrease patient motion
 Increase contrast
 Increase uniformity of breast tissue
 Increase image sharpness by decreasing
thickness thus decrease focal spot
degradation
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COMPRESSION PROCEDURE
Place towel
 Place scale
 Place friend’s (soon to be enemy’s) breast
on top of scale
 Compress in power mode until it stops
(never mind the screaming of your new
enemy)
 Compress in manual until it stops (same
as above)
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COMPRESSION PROCEDURE
Place towel
 Place scale
 Place several towels on top of scale
 Compress in power until it stops
 Compress in manual until it stops
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FILM/SCREEN CONTACT
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Performed on all new cassettes and/or
semi-annual
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More critical than general radiography
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Highlights areas of decreased sharpness
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Fine 30-40 copper wire mesh screen used
FILM/SCREEN CONTACT PROCEDURE
Clean cassettes
 Let sit for 15 minutes
 Employ 25-28kVp, no grid, manual mas
with .5 seconds
 Paddle all the way up with acrylic
 Wire mesh on top of screen
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FILM/SCREEN ANALYSIS
.7-.8OD near chest wall
 Stand 3-6ft back
 If densities over 1 cm appear, clean and
retest.
 Remove if large density still appears.
 Several small densities acceptable.
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DARKROOM FOG
Inspect with all lights off
 Be aware of luminescent or
phosphorescent items
 Use radiation exposed film
 MQSA states fog should be no >.05 OD
when exposed for 2 min.
 Problems usually lie in safelight position or
filters
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DARKROOM PROCEDURE
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Load cassette in total darkness
Expose phantom to 1.0 OD
Inspect safelights
Turn off lights, inspect
Remove film, insert into template emulsion up
Expose sections to safelights
Run film then measure densities on each side of
lines
Safelights
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Filters should correspond with green light
sensitive film
Lamps ~4 ft from work area
Wratten 1 or 2, Kodak GBX-2 good examples of
filters
No >15watt bulb in overhead fixture
No >7.5 watt in closer fixtures
Printing on filter should face out
Change filters every 1-2 years
AIR QUALITY
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Temperature: 70 degrees F
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Humidity: 30-50%
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Ventilation: for image quality and
technologists’ health
PROCESSOR MAINTENANCE
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Developer temperature
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Increase can cause fog
Decrease can result in:
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Fixer temperature
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Decrease in film speed and contrast
Higher dose to pt
Decrease can affect archival of film
Wash-water temperature
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Can cause biological growth in tank
Can affect developer and fixer temps, improper wash
PROCESSING CONTINUED…
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Chemical replenishment
 Rates
inconsistent when processor left on and
not used
 Check solution levels
PROCESSING: STANDARD
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Typically used for general radiography
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Faster cycle time (usually 90sec)
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Developer immersion ~23 sec
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Can accommodate single and double
PROCESSING: EXTENDED
Difference from standard is developer
immersion time (~45sec)
 “Push” more contrast and speed from the
film
 Less exposure needed with increase in
film speed
 Increase in tube life
 Downfall is an increase in noise
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TYPES OF PROCESSORS
Small desktop
 DISADVANTAGES
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 Straight-through
require careful adjustments to
replenishment
 Developer not sprayed evenly
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ADVANTAGES
 Cost,
small, fewer rollers, two developer stations,
 Less chance of oxidation
TYPES OF PROCESSORS
Large stand-alone
 DISADVANTAGES
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 Artifacts
from rollers
 Space
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ADVANTAGES
 Agitates
chemicals which increases supply of fresh
chemicals
ARTIFACTS
Processing
 Environmental
 Handling
 Positioning
 Equipment
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SENSITOMETRIC STRIP
Establishing the baseline
Expose and process 5 strips
 Average readings for temporary base
 Process one strip per day for 5 days
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 If
strip is out of tolerance, correct and repeat
 Watch for trend due to seasoning effect
Average these 5 strips for new base
 Baseline maintained unless film, chemistry
or processing altered
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CROSSOVER
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Performed when changing box of film
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10-12 sheets remaining in old box
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Do not perform after processor cleaning
CROSSOVER PROCEDURE
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Perform in total darkness
Expose 5 old and 5 new
Alternate old and new
Distinguish old from new
Measure steps used in daily QC
Average 5 readings from each box
Subtract old from new
Add/Subtract results to/from original aim values
CROSSOVER RESULTS
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Results must be within +/- .10
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If greater than .15 difference, contact film
manufacturer representative
(Dudes
Prefer) (Sex, Violence
and Partying) over (Visiting)
(Relatives For) (Christmas Day
Feasts.)
QUALITY ASSURANCE
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Defined as all those planned and
systematic actions necessary to provide
high image quality.
QUALITY MANAGEMENT
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Part of the management function which
determines and controls quality policy.
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Making appointments
Call back protocol
Obtaining previous mammograms
Patient education
Patient intake
Problem solving
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QUALITY CONTROL
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The set of operations necessary to
maintain or improve quality.
QUALITY SYSTEM
Assignment of responsibility
 Establishment of standards
 Staff training
 Proper documentation of procedures
 QC of equipment at installation and
throughout its life
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MQSA of 1992
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As of Oct 1, 1994, all mammography facilities in
the U.S. (except those of Dept of Veterans
Affairs) were required to be certified by the FDA
as meeting mammography quality in order to
lawfully continue to perform Mammography.
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Goal: to assure that Mammography is safe and
reliable to allow detection of breast CA in its
earliest most treatable stages.
MQSA REGULATIONS
To operate lawfully, a mammography facility
must be certified by the FDA.
 In order to be certified, a facility must first be
accredited by a federally-approved private
nonprofit or state accreditation body.
 To be accredited, the facility must undergo
periodic review of clinical images; surveyed
annually by a medical physicist; meet standards
for personnel qualifications, equipment QA
programs, and record keeping and reporting.
 Facility must undergo annual inspections.
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ACCREDITATION
A survey form completed by facility
 Phantom images submitted to evaluate
image quality
 Dosimeter visible on phantom and dose
measured
 Clinical images submitted for evaluation
 Once initial paperwork approved, facility
submits 30 days of processor QC strips
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CERTIFICATION
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Awarded by the FDA as providing quality
mammography services.
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This is awarded upon accreditation by a
federally-approved accreditation body:
ACR; States of Arkansas, California, and
Iowa
RESPONSIBLE INDIVIDUALS
TECHNOLOGIST
 RADIOLOGIST
 PHYSICIST
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Interpreting Physicians
Initial Qualifications
State license
Diagnostic radiology certification OR 3 months of
formal training
• 60 hours of category I CME in mammography
• 240+ mammograms interpreted under direct
supervision
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In the 6 months immediately prior to independent
interpretation OR
 If board certified at first allowable time, within the
last 2 years of residency
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Interpreting Physicians
Continuing Requirements
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Continuing experience
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Interpret at least 960 examinations / 24 months
Continuing education
At least 15 category I CME credits / 36 months
 At least 6 of the 15 CME units must be in each
mammographic modality used
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8 hours of training in each mammographic
modality before independent use
Radiologic Technologists
Initial Qualifications
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State license OR certified by FDAapproved body
40 hours of documented mammography
training
Performing at least 25 examinations under
direct supervision
8 hours of training in each mammographic
modality to be used
Radiologic Technologists
Continuing Requirements
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Continuing experience
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Continuing education
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At least 200 examinations / 24 months
At least 15 CEUs / 36 months
At least 6 of the 15 CEUs must be in each
mammographic modality used
8 hours of training in each mammographic
modality used before independent use
Radiologic Technologists
Reestablishing Qualifications
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Continuing experience
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Complete 25 examinations under direct
supervision
Continuing education
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Bring total continuing education credits up to
15 CEUs / 36 months
Medical Physicists
Initial Requirements
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Licensed or approved by a State OR
Certified by FDA-approved body
Master’s or higher degree in a physical
science
20 semester hours of physics
20 hours of documented mammography
survey training
One facility and 10 units surveyed
8 hours of training in each modality
surveyed before surveying independently
Medical Physicists
Alternative Initial Requirements*
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Licensed or approved by a State OR
Certified by FDA-approved body
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Maintained active status
For physicists who were qualified under the interim regulations
Medical Physicists
Alternative Initial Requirements*
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(cont.)
Prior April 28, 1999, have:
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Bachelor’s degree in physical science with at
least 10 semester hours of physics
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40 hours of documented mammography
survey training after earning the bachelor’s
degree
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One facility and 20 units surveyed after
earning the bachelor’s degree
Medical Physicists
Continuing Requirements
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Continuing experience
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Continuing education
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Survey at least 2 facilities and 6 units / 24
months
At least 15 CEUs / 36 months
8 hours of training in any modality before
surveying independently
MANUAL
QC MANUAL
 QA MANUAL
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QA MANUAL
Details of acceptance
 Personnel qualifications and
documentations.
 Department policy
 Safety standards
 Biohazards
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QC MANUAL
The QC manual is pertinent to ease the
inspection process. It lists:
 Test procedures
 Test frequencies
 Test standards
 Unacceptable results as listed as well as
the corrections made for them.
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