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MAMMOGRAPHY QA

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

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MAMMOGRAPHY QA

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

  2. MQSA National Statistics • FEDERAL LEGISLATION • OCT. 1, 1994 • EQUIPMENT DESIGN & OPERATION STANDARDS (DEDICATED UNITS) • INTENSIVE QUALITY CONTROL PROGRAM WHAT DOES MQSA REPRESENT? __________________

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

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

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

  7. Hypo RetentionChecks for what? Fixer left on film – “Archival Properties”

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

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

  11. These specks were produced by flakes trapped between the film and the screen – Not calcifications in the breast

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

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

  14. FILM SCREEN & DIGITAL Mammography EquipmentBushong – 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.

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

  16. Mammography Imaging System • High frequency generators • TARGET MATERIAL: • Tungsten (W), (z = ____?) 74 • Molybdenum (Mo), (z = ___ ?) 42 • or rhodium (Rh) target (z = ___ ?) 45 • Focal spot sizes 0.3/0.1 mm (Bushong) • with tilted tube • Maximum 600 mAs limit

  17. Mammography Imaging System • Inherent filtration 0.1 Al equivalent • Heel effect used to advantage • Compression reduces motion, improves spatial resolution, lowers patient dose • High-transmission cellular grid • Automatic exposure control

  18. DEDICATED MAMMOGRAPIC EQUIPMENT • KVP RANGE : 23 – 28 kvp (BUSHONG) • TARGETS: Molybdenum / Rhodium (vs. Tungsten) • FOCAL SPOTS • (can range from 0.1 – 0.6) • SID 60 –70 cm (vs. 100cm) • Compression Paddle • Heel Effect (fat/cat) • GRIDS : 4:1 or 5:1 (vs 8 to16:1) What does “DEDICATED” Mean in the above title?

  19. 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

  20. DIGITAL MAMMO • 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

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

  22. Compression in mammography has three principal advantages: improved spatial resolution, improved contrast resolution, and lower patient dose. Can affect: kVp & mAs ranges

  23. A high-transmission cellular grid designed specifically for 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.

  24. Position of AEC over breast tissue

  25. Remove all ambient light when possible – for better images

  26. Risk Factors for Breast Cancer • Age: the older you are, the higher the risk • Family history: mother, sister with breast cancer • Genetics: presence of BRCA1 or BRCA2 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

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