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Resident Physics Series

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Presentation on theme: "Resident Physics Series"— Presentation transcript:

1 Resident Physics Series
ACR Mammography Protocols

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

3 Facility Responsibility
Designate One Lead Interpreting Physician

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

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

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

7 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

8 Radiologist’s Responsibilities
Select a medical physicist administers QC program performs physicist’s tests Review physicist’s test results

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

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

11 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.”

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

13 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)

14 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

15 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

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

17 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%

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

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

20 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

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

22 A Poor Phantom Image

23 Artifact Identification
Artifact evaluation / description determination of artifact source processor other equipment Done with phantom film

24 Physicist’s Responsibilities
Viewing conditions ambient light viewbox brightness My experience Ambient lighting often ignored

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

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

27 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

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

29 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

30 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

31 Semi-annual Technologist’s Responsibilities
Screen Film Contact

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

33 From the FDA

34 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

35 MQSA Violation Levels Level 1 (Most serious) Level 2 Level 3
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.

36 FDA Inspection Violations (2007)

37 Why Sites Failed Accreditation 2001 - 2003

38 Units Passing Accreditation 2001-2003

39 Units Passing Accreditation 2003

40

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

42 What is FFDM? Full Field Digital Mammography

43 How Popular is FFDM

44 Number of Accredited FFDM Units
Nov 03 Nov 07

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

46 Number of Accredited Units
Nov 03 Nov 07

47 The End Questions?


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