1 MAMMOGRAPHY QA Quality Assurance Quality Control Equipment

1 MAMMOGRAPHY QA Quality Assurance, Quality Control & Equipment Bushong Ch. 19 & 20 PURPOSE OF QC ASSURES OPTIMUM PATIENT CARE by avoiding unnecessary repeat exposures due to artifacts, processing problems and equipment failure Rev. Spring 2009/2010

MQSA National Statistics 2 2 • FEDERAL LEGISLATION • OCT. 1, 1994 • EQUIPMENT DESIGN & OPERATION STANDARDS (DEDICATED UNITS) • INTENSIVE QUALITY CONTROL PROGRAM Certification statistics, as of March 1, 2010 Certified facilities with FFDM 2 units / Accredited FFDM units 12, 623 5, 402 / 7, 963 Total annual mammography procedures reported, as of March 1, 20101 38, 057, 377 80. 2% Percent of inspections with no violation WHAT DOES MQSA REPRESENT? _________

3 3 n n n MAMMO & Quality Control Quality control is an equipment and processing evaluation program in diagnostic imaging centers. QC involves testing, record keeping and evaluation of imaging equipment and processing QC Team includes Radiographer/Mammographer, Physicists and Radiologist QA involves people – scheduling, reports, waiting time and follow up exams “double reads” See Bushong – CH. 20 PG 333

4 Elements of QC 4 n FREQUENCY n Daily pg 333 n TASKS n Darkroom Clean Processor QC – n sensitometry/densitometry and DEVELOPER temp n Weekly n n n Monthly/Quarterly n n Screen Cleaning VISUAL CHECK Phantom Images Repeat Analysis (should be less than 2% repeat rate - diagnostic rad = 5%)

5 5 MAMMO QC SEMIANNUALLY n DARKROOM FOG n SCREEN/FILM CONTACT n COMPRESSION NOT MORE THAN n 40 PSI (25 PSI is average) n MONTHLY Checks

6 QUALITY CONTROL TOOLS 6 n n n PHANTOM DIGITAL THERMOMETER SCREEN CLEANER LINT FREE CLOTHS FIXER RETENTION TESTING KIT CHARTS

7 7 Hypo Retention Checks for what? Fixer left on film – “Archival Properties”

8 8 WIRE MESH Checks for what How long should you wait after loading a cassette to use it? 15 min & placed in an upright position

9 9 Types of Safelights? Wratten 6 b n GBX n Check for leaks/cracks? n How often? Bulb Wattage?

10 10 For those still using film… clean crossovers daily Use “dedicated” processor for only mammo

11 11 DAILY QUALITY CONTROL DARKROOM CLEANLINESS WIPE COUNTERS DUST VENTS & LIGHTS These specks were produced by flakes trapped between the film and the screen – Not calcifications in the breast PROCESSOR QUALITY CONTROL Sensitometer strip Densitometer step PHANTOM IMAGE Assures quality control of Radiographic Image &graph results VISUAL CHECKLIST MONTHLY FIXER RETENTION MONTHLY REPEAT ANALYSIS DARKROOM FOG SEMI-ANNUAL FILM/SCREEN CONTACT SEMI-ANNUAL COMPRESSION (25 PSI) SEMI-ANNUAL

PHANTOM IMAGES 12 12 n Daily - to assure film density, contrast, uniformity and image quality are optimum – Using the SAME cassette and technical factors each time n n 4/5 masses 3/4 specks 4/6 fibers should be seen n (see pg 500 review book) n n

13 13 REPEAT ANALYSIS n Mammography should be less than 2% Number of repeated film Repeat Rate = -------------- X 100 Total # of films n n Diagnostic Radiology = less than 5% n Students = less than 10 %

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15 FILM SCREEN & DIGITAL Mammography Equipment Bushong – Ch. 19 When the x-ray tube is tilted in its housing, the effective focal spot is small, the x-ray intensity is more uniform, and tissue against the chest is imaged.

16 EQUIPMENT DIFFERENCES 16 TARGET MATERIAL – n MOLYBDENUM n MO/RHODIUM n SMALLER FOCAL SPOTS n SHORTER SID n KVP RANGES n LOW ~ 24 – 30 23 – 28 (Bushong) n n (type of target used) MAS n PHOTOCELLS n

17 Mammography Imaging System n High frequency generators n TARGET MATERIAL: 17 n Tungsten (W), (z = ____? ) 74 n Molybdenum (Mo), (z = ___ ? ) 42 n or rhodium (Rh) target (z = ___ ? ) 45 n Focal spot sizes 0. 3/0. 1 mm (Bushong) n with tilted tube n Maximum 600 m. As limit

18 Mammography Imaging System n Inherent filtration 0. 1 Al equivalent n Heel effect used to advantage n Compression reduces motion, improves spatial resolution, lowers patient dose n High-transmission cellular grid n Automatic exposure control 18

19 19 DEDICATED MAMMOGRAPIC EQUIPMENT ØKVP RANGE : 23 – 28 kvp (BUSHONG) ØTARGETS: Molybdenum / Rhodium (vs. Tungsten) ØFOCAL SPOTS Ø(can range from 0. 1 – 0. 6) ØSID 60 – 70 cm (vs. 100 cm) ØCompression Paddle What does “DEDICATED” Mean in the above title? ØHeel Effect (fat/cat) ØGRIDS : 4: 1 or 5: 1 (vs 8 to 16: 1)

20 20 Anode Heel Effect – Which portion should Be under the cathode Side of the TUBE? The heel effect can be used to advantage in mammography by positioning the cathode toward the chest wall to produce

21 DIGITAL MAMMO 21 n DIGITAL has a resolution of approximately 5 lp/mm – but also has MORE CONTRAST § CONVENTIONAL FILM/SCREEN: resolution of approximately 12 lp/mm No need for an additional exposure to the patient

22 MAMMOGRAPHIC IMAGES The BREAST has a low subject contrast – little differences in density = soft tissue radiography

n 23 23 Compression in mammography has three principal advantages: improved spatial resolution, improved contrast resolution, and lower patient dose. Can affect: k. Vp & m. As ranges

24 • A high-transmission cellular grid designed specifically for 24 mammography. • 4: 1 or 5: 1 grid ratio • 40 line/cm frequency • 4: 1 grid doubles pt dose – • but improves contrast significantly p 327 • Correct way to load mammography film and position the cassette. • Spatial resolution improves when the x-ray film is placed closest to the breast and • between the x-ray tube and the radiographic intensifying screen.

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26 26 Position of AEC over breast tissue

27 27 Remove all ambient light when possible – for better images

28 28 n n n n n Risk Factors for Breast Cancer Age: the older you are, the higher the risk Family history: mother, sister with breast cancer Genetics: presence of BRCA 1 or BRCA 2 genes Breast architecture; dense breast tissue Menstruation: onset before age 12 Menopause: onset after age 55 Prolonged use of estrogen Late age at birth of first child or no children Education: risk increases with higher education Socioeconomics: risk increases with higher status