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Image Production and Evaluation. NOTE: QA AND QC ARE USED INTERCHANGABLY IN APPLETON AND LANGE. Intensifying screen (ref: pg 59 Mosby, 190 Bushong) . Base Reflective layer Active Layer Protective layer. Intensifying.Screen: Detail and speed.
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Image Production and Evaluation NOTE: QA AND QC ARE USED INTERCHANGABLY IN APPLETON AND LANGE
Intensifying screen(ref: pg 59 Mosby, 190 Bushong) • Base • Reflective layer • Active Layer • Protective layer
Intensifying.Screen: Detail and speed • Thicker the active layer: less detail and more speed • Larger the phospher:less detail and more speed • Formula: old screen new screen
PSP CRT ADC IP CR DR FOV field of view or how much of the patient is included in the matrix Matrix-rows and columns of pixels (512 x512) Pixel size As matrix increase, pixel size decreases As FOV increases, pixel size increases As pixel size increases, resolutions decreases Digital Imaging
TARGET ANGLELINE FOCUS PRINCIPLEPG. 40 i-n, Mosby • Actual • Effective • Large angle • small angle • anode heel
MAMMOGRAPHY • Use very low KVP 23-28 • molybdenum targets • High MAS
DEFINE • EXIT (REMNANT RADIATION) • LATENT IMAGE • MANIFEST IMAGE
Magnification: FOR EVERY 1” OF OID INCREASE, SID MUST INCREASE BY 7”WALLACE PG 27-33 • Mag. Factor - SID SOD • SOD ---- SID - OID • IMAGE SIZE -image = SID object SOD • % OF MAG- OID SOD X 100 • #s 25,45 57,87,93
DENSITY • OD or Logarithm of opacity • Ratio of amount of light incident on film to the amount of light transmitted thru film (Mosby, pg. 53) • Controlling factors • mAs • kVP • Distance • Film/screen • Grids • Collimation • Anatomy/pathology • Anode Heel • Filtration
Detail • Focal spot size • Screen speed • SID • OID • Motion artifact
CONTRAST • KVP • GRID • FIELD SIZE • Filtration • Anatomy and pathology • HIGH, SHORT • LOW, LONG
CHARACTERISTIC/H&D CURVE PG 58 MOSBY • Exposure error latitude • Contrast latitude • speed of film • base/fog • processing
DIFFERENTIAL ABSORPTION & ATTENUATION • Difference between x-rays absorbed through photoelectric effect and those not absorbed at all.
Quantum Mottle • Mottled appearance (looking through a mist) • low mas-increase QM • high speed film- increase QM
GRIDS • GRID RATIO: HEIGHT DIVIDED BY DISTANCE • AFFECT ON CONTRAST • MULTIPLYING FACTOR • GRID CUTOFF
FOCAL SPOT/ BLUR • Umbra/penumbra or focal spot blur • Small FS = less • Large FS = more • Increased SID = less • decreased SID = more • increased OID = more • decreased OID = less
FILM CONSTRUCTION (Pg. 166-167 Bushong)/Cassette • BASE • EMULSION
CHARACTERISTIC COMPTON INFRARED CLASSICAL, THOMSON, COHERENT PHOTOELECTRIC BREMSTRAULING PAIR PRODUCTION PHOTO-DISINTEGRATION INTERACTIONS