resident physics series acr mammography protocols
TRANSCRIPT
Resident Physics Series
ACR Mammography Protocols
Mammography Quality Standards Act (MQSA)
“to ensure the safety and reliability of mammography and help detect breast cancer in its earliest, most treatable stages”
Mammography practice under federal control (FDA)
19921992
MQSA Requirements
Yearly physics surveysYearly FDA inspections
Georgia x-ray regulators on contract with FDAFY 2013
No violations: 87%
Facility Accreditation by “Accrediting Body”
American College of Radiology (ACR)State of ArkansasState of IowaState of Texas
FDA Facility & Procedure CountJune, 2006 Late 2013 %
Change
Total certified facilities
8850 8691 -1.8
Total accredited units
13588 12195 -10.3
Certified facilities with FFDM units
1027 8004 +679.4
Accredited FFDM units
1455 12195 +738.1
Annual mammography procedures
33,940,037
38,596,266
+13.7
Number of Accredited FFDM Units
Jun 11Jun 11Nov 03Nov 03
Number of Accredited Units
Jun 11Jun 11Nov 03Nov 03
% FFDM Units
Dec 2003Dec 2003
Jun 2011Jun 2011
FDA-Approved FFDM Units Last 5 YearsDate Manufacture
rModel
6/15/11
Hologic Selenia Encore Direct
4/28/11
Sectra MicroDose Mammography L30 Photon Counting
2/11/11
Hologic Selenia Dimensions Digital Breast Tomosynthesis (DBT)
Direct
2/11/11
Siemens Mammomat Inspiration Direct
11/3/10
Carestream Directview Computed Radiography (CR) CR
2/11/09
Hologic Selenia Dimensions 2D Direct
2/11/09
Hologic Selenia S Direct
2/11/09
Siemens Mammomat Novation S Direct
11/2007
Hologic Selenia with Tungsten target Direct
07/10/06
Fuji Computed Radiography Mammography Suite
CR
04/11/06
General Electric
Senographe Essential Indirect
Mammography QC Manual
RadiologistClinical Image QualityRadiologic TechnologistMedical Physicist
Revised Edition, 1999Revised Edition, 1999
SectionsSections
Quality Assurance (QA)
Every imaging procedure is necessary & appropriate to clinical problem at hand
images contain information critical to solution of that problem
QA should ensureQA should ensure
Quality Assurance (QA)recorded information is
correctly interpretedmade available to patient’s physician in a
timely fashion consistent with image quality objectives,
examination results in lowest possibleradiation exposurecostinconvenience to the patient
Quality Control (QC)
Acceptance Testingdetection of defects in equipment that is
newly installed or has undergone major repair
BaselinesEstablishment of baseline equipment
performance quantitative data when system operating properly
QC is integral part of QAQC is integral part of QA
Quality Control (QC)
DiagnosisDiagnosis of changes in equipment
performance before they become radiologically apparent
VerificationVerification of correction of causes of
deterioration in equipment performance
Facility Responsibility
Designate One Lead Interpreting Physician
Lead Physician’s Responsibilities
Ensure technologists have adequateorientation
based on procedure manualtrainingcontinuing education
Ensure effective QC program
Radiologist’s Responsibilities
Designate one technologist responsible for QC
QC tech can delegate responsibilities
Radiologist’s Responsibilities
Ensure availability of appropriate test equipment
Arrange staffing / scheduling to allow time for QC
Radiologist’s Responsibilities
provide frequent consistent positive & negative feedback to technologists about film quality & QC
Review technologist’s test resultsno less than every 3 monthsmore often if inconsistent
results
Radiologist’s Responsibilities
Select a medical physicistadministers QC programperforms physicist’s tests
Review physicist’s test results
Radiologist’s Responsibilities
Oversee or designate qualified individual to oversee radiation protection program foremployeespatientsindividuals in surrounding area
Radiologist’s Responsibilities
Ensure proper maintenance of records in QC procedures manualemployee qualificationsmammography technique / proceduresquality control / safety / protectioninfection control
Radiologist’s Responsibilities
“The radiologist is ultimately responsible for the quality of films produced under his or her direction and bears ultimate responsibility for both proper QC testing and QA procedures in mammography.”
“The radiologist is ultimately responsible for the quality of films produced under his or her direction and bears ultimate responsibility for both proper QC testing and QA procedures in mammography.”
The Proliferation of Digital MammographyTotal mammography units in US (10/1/2010)
12,445Total digital mammography units (10/1/2010
8748 (70.3%)Total digital mammography units (4/1/2010
or 6 months ago)8195 (65.2%)
Increase in digital units~ 92/month
Physicists & Digital MammoraphyPhysicist must insure equipment meets
manufacturer’s specificationsEquipment specs now defined by
manufacturer, not ACR/FDA
Physicist’s Responsibilities
Note: All physicistNote: All physicist’’s tests are to be done s tests are to be done annuallyannually or after tube replacement or or after tube replacement or major servicemajor service
Physicist’s Responsibilities: Mammography Unit Assembly Evaluation
mechanical stability / identification of sharp edges
receptor stabilitylocks / motions / detentsoperator shieldingthickness scale accuracyindicator lights workingtechnique chart posted (see next
slide)
Technique ChartEven though most mammo is
phototimed, still need technique chartFor given breast size, density, view
specify machine set-upPhototimer mode (auto standard,
contrast, dose, …)Density (-2, -1, 0, …)
Technique Chart
Wrong (my opinion)Display kVp, mAs, target, filter calculated by
machine for given image
Correct (my opinion)Display machine settings selectable by
technologist for this breast and view
Should provide enough guidance to allow a technologist who has not worked in this room or facility to properly set up a study
Physicist’s Responsibilities: Mammography Unit Assembly Evaluation
Cassettes slide smoothly into/out of holderOverride available for auto-decompression
display must indicate when auto-decompression turned off
Manual release of compression if power lost
Collimation Assessment
x-ray light field alignmentbeam does not exceed receptor
by > 2% SIDcompression paddle / receptor
alignment at chest wall within 1% SIDpaddle not visible on image
Image should fill filmMany units by design will not do this
Physicist’s Responsibilities
Focal Spot Performancelimiting resolution pattern
kVp accuracy / reproducibility
Beam quality (HVL)minimum & maximum
minimum: patient dose maximum: image contrast
Automatic Exposure Control (AEC / Phototiming)kVp trackingThickness trackingimage mode tracking (cassette sizes, w
w/o grid)automatic mode tracking
unit selects kVp, target, filterdensity control
even steps of ~ 15-20% Density Step Changes
0
2
4
6
8
10
12
14
16
18
-5 -4 -3 -2 -1 0 1 2 3 4 5
Step
% C
han
ge
Series1
Physicist’s Responsibilities:
Screen Uniformitycompare O.D. of each cassette using
phototimerAEC Reproducibility
Physicist’s Responsibilities
Breast Entrance Exposure, Average Glandular Dose, RMI-156 “accreditation” phantom used for
entrance exposure / average glandular dose
Breast Average Glandular Dose Limits
0.3 rad (300 mrads, 3 mGy) maximum per view for screen-film receptors using a gridSame for film and digital
0.1 rad (100 mrads, 1 mGy) maximum per view for non-grid screen-film receptors
Radiation output rate > 800 mR/sec
Image Quality Evaluationuse RMI-156 “accreditation” phantomrecord
fibersspeck groupsmassesoptical densitiestechnique
A Poor Phantom Image
Artifact Identification
Artifact evaluation / descriptiondetermination of artifact source
processor other equipment
Done with phantomfilm
Physicist’s Responsibilities
Viewing conditionsambient lightviewbox brightness
My experienceAmbient lighting
often ignored
Technologist’s Responsibilities
Dailydarkroom cleanlinessprocessor quality control
sensitometric data
Weeklyscreen cleanlinessviewboxes and viewing
conditionsPhantom images
All QC must not only be performed All QC must not only be performed but must be but must be documenteddocumented!!
Speed
1.11
1.31
1.51
6/2/
97
6/3/
97
6/4/
97
6/5/
97
6/6/
97
6/9/
97
6/10
/97
6/11
/97
6/12
/97
6/13
/97
6/16
/97
6/17
/97
6/18
/97
6/19
/97
6/20
/97
6/23
/97
6/24
/97
6/25
/97
6/26
/97
6/27
/97
6/30
/97
7/1/
97
7/2/
97
7/3/
97
7/7/
97
7/8/
97
7/9/
97
7/10
/97
7/11
/97
7/14
/97
O.D
.
Technologist’s ResponsibilitiesMonthly: Visual Checklist
visual checklistSID indicatorangle indicatorlocksfield lightsmooth motions
Technologist’s ResponsibilitiesMonthly: Visual Checklist
cassette lockIs cassette held firmed in place when tubestand
tilted
Compression device & firm compressionSmooth edgesHolds pressure
hand switch placementvisibilityswitches/ lights/ meterscones/ collimators
Technologist’s ResponsibilitiesQuarterly
Fixer retention analysisFixer affects
archivability of filmsRepeat analysis
breakdown by cause motion positioning technique static etc.
Semi-Annual Technologist’s Responsibilities: Darkroom Fog
must use sensitized film
partially cover previously exposed phantom film in darkroom for 2 minutes
up to .05 O.D. increase acceptable
Semi-annual Technologist’s ResponsibilitiesScreen Film Contact
40 lines/inch Copper meshsubjective resultspoor contact can result if time (15 minutes)
not provided for air to bleed out of cassette after closingNOTE: 15 minutes between cassette loading
& exposure must be provided for all clinical films to insure good contact
Semi-annual Technologist’s ResponsibilitiesScreen Film Contact
Semi-Annual Technologist’s Responsibilities
Compressioncan use bathroom scale covered with
towel25 - 40 pounds for automatic systemsat least 25 pounds for manual
compression
The End
Questions?