Quality Assurance, Quality Control & Equipment Bushong Ch. 19 & 20 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

EQUIPMENT DESIGN & OPERATION STANDARDS (DEDICATED UNITS) MQSA National Statistics FEDERAL LEGISLATION OCT. 1, 1994 EQUIPMENT DESIGN & OPERATION STANDARDS (DEDICATED UNITS) INTENSIVE QUALITY CONTROL PROGRAM Certification statistics, as of March 1, 2010   12,623 Certified facilities with FFDM2 units / Accredited FFDM units 5,402 / 7,963   Total annual mammography procedures reported, as of March 1, 20101 38,057,377   Percent of inspections with no violation 80.2% WHAT DOES MQSA REPRESENT? __________________ 1 This number is an aggregate of the total number of procedures performed annually as reported by facilities to

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

Elements of QC pg 333 FREQUENCY TASKS Daily Weekly Monthly/Quarterly 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%)

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

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

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

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

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

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

Not calcifications in the breast VISUAL CHECKLIST MONTHLY FIXER RETENTION REPEAT ANALYSIS DARKROOM FOG SEMI-ANNUAL FILM/SCREEN CONTACT COMPRESSION (25 PSI) These specks were produced by flakes trapped between the film and the screen – Not calcifications in the breast

PHANTOM IMAGES 4/5 masses 3/4specks 4/6 fibers should be seen 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)

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 %

Mammography Equipment Bushong – Ch. 19 FILM SCREEN & DIGITAL 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.

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

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

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

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?

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

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

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

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

but improves contrast significantly p 327 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.

Position of AEC over breast tissue

Remove all ambient light when possible – for better images

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