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George David Resident Physics Series ACR Mammography Protocols.

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Presentation on theme: "George David Resident Physics Series ACR Mammography Protocols."— Presentation transcript:

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2 George David Resident Physics Series ACR Mammography Protocols

3 George David Mammography QC Manual Radiologist Clinical Image Quality Radiologic Technologist Medical Physicist Revised Edition, 1999 Sections

4 George David Facility Responsibility Designate One Lead Interpreting Physician

5 George David Radiologist’s Responsibilities Designate one technologist responsible for QC QC tech can delegate responsibilities to others

6 Lead Physician’s Responsibilities Ensure technologists have adequate  orientation »based on procedure manual  training  continuing education Ensure effective QC program

7 George David Radiologist’s Responsibilities Ensure availability of appropriate test equipment Arrange staffing / scheduling to allow time for QC

8 George David Radiologist’s Responsibilities provide frequent consistent positive & negative feedback to technologists about film quality & QC Review technologist’s test results  no less than every 3 months  more often if inconsistent results

9 George David Radiologist’s Responsibilities Select a medical physicist  administers QC program  performs physicist’s tests Review physicist’s test results

10 George David Radiologist’s Responsibilities Oversee or designate qualified individual to oversee radiation protection program for  employees  patients  individuals in surrounding area

11 George David Radiologist’s Responsibilities Ensure proper maintenance of records in QC procedures manual  employee qualifications  mammography technique / procedures  quality control / safety / protection  infection control

12 George David 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.”

13 George David Physicist’s Responsibilities Note: All physicist’s tests are to be done annually or after tube replacement or major serviceNote: All physicist’s tests are to be done annually or after tube replacement or major service

14 Physicist’s Responsibilities: Mammography Unit Assembly Evaluation mechanical stability / identification of sharp edges receptor stability locks / motions / detents operator shielding thickness scale accuracy indicator lights working technique chart posted (see next slide)

15 Physicist’s Responsibilities: Mammography Unit Assembly Evaluation Cassettes slide smoothly into/out of holder Override available for auto- decompression  display must indicate when auto-decompression turned off Manual release of compression if power lost

16 George David Collimation Assessment x-ray light field alignment beam does not exceed receptor by > 2% SID compression paddle / receptor alignment at chest wall within 1% SID  paddle not visible on image Image should fill film  Many units by design will not do this

17 George David Physicist’s Responsibilities Focal Spot Performance  limiting resolution pattern kVp accuracy / reproducibility Beam quality (HVL)  minimum & maximum »minimum: patient dose »maximum: image contrast

18 Automatic Exposure Control (AEC / Phototiming) kVp tracking Thickness tracking image mode tracking (cassette sizes, w w/o grid) automatic mode tracking  unit selects kVp, target, filter density control  even steps of ~ 15-20%

19 Physicist’s Responsibilities: Screen Uniformity  compare O.D. of each cassette using phototimer AEC Reproducibility

20 Physicist’s Responsibilities Breast Entrance Exposure, Average Glandular Dose,  RMI-156 “accreditation” phantom used for entrance exposure / average glandular dose

21 Breast Average Glandular Dose Limits 0.3 rad (300 mrads, 3 mGy) maximum per view for screen-film receptors using a grid 0.1 rad (100 mrads, 1 mGy) maximum per view for non-grid screen-film receptors Radiation output rate > 800 mR/sec

22 Image Quality Evaluation use RMI-156 “accreditation” phantom record  fibers  speck groups  masses  optical densities  technique

23 A Poor Phantom Image

24 George David Artifact Identification Artifact evaluation / description  determination of artifact source »processor »other equipment Done with phantom film

25 George David Physicist’s Responsibilities Viewing conditions  ambient light  viewbox brightness My experience  Ambient lighting often ignored

26 Technologist’s Responsibilities Daily  darkroom cleanliness  processor quality control »sensitometric data Weekly  screen cleanliness  viewboxes and viewing conditions  Phantom images All QC must not only be performed but must be documented!

27 Technologist’s Responsibilities Monthly: Visual Checklist visual checklist SID indicator angle indicator locks field light smooth motions

28 Technologist’s Responsibilities Monthly: Visual Checklist cassette lock  Is cassette held firmed in place when tubestand tilted Compression device & firm compression  Smooth edges  Holds pressure hand switch placement visibility switches/ lights/ meters cones/ collimators

29 Technologist’s Responsibilities Quarterly Fixer retention analysis  Fixer affects archivability of films Repeat analysis  breakdown by cause »motion »positioning »technique »static »etc.

30 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

31 Semi-annual Technologist’s Responsibilities Screen Film Contact 40 lines/inch Copper mesh subjective results poor contact can result if time (15 minutes) not provided for air to bleed out of cassette after closing  NOTE: 15 minutes between cassette loading & exposure must be provided for all clinical films to insure good contact

32 Semi-annual Technologist’s Responsibilities Screen Film Contact

33 Semi-Annual Technologist’s Responsibilities Compression can use bathroom scale covered with towel pounds for automatic systems at least 25 pounds for manual compression

34 George David From the FDA

35 FDA Facility & Procedure Count (as of November 1, 2007) Total certified facilities: 8,837  Total accredited units: 13,590 Certified facilities with FFDM units: 2,434  Accredited FFDM units: 3,644 Total annual mammography procedures: 35,385,494

36 George David MQSA Violation Levels Level 1 (Most serious)  Example: Unqualified personnel  Requires written response within 15 days Level 2  May compromise quality of service provided  Example: No physics survey within 14 months  Requires written response within 30 days Level 3  Minor deviations from MQSA standards  Example: missing QC records  No written response required.

37 George David FDA Inspection Violations (2007)

38 Why Sites Failed Accreditation

39 Units Passing Accreditation

40 Units Passing Accreditation 2003

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42 George David What is FFDM? Fly Fishing Democratic Mothers Far Field Dignified Marketing Fat Farm for Dumb Maniacs

43 George David What is FFDM? Full Field Digital Mammography

44 George David How Popular is FFDM

45 Number of Accredited FFDM Units Nov 07 Nov 03

46 Is the Overall # of Mammo Units Increasing or Are these Replacement Units?

47 Number of Accredited Units Nov 07 Nov 03

48 George David The End Questions?


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