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Image Production and Evaluation

Image Production and Evaluation

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Image Production and Evaluation

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  1. Image Production and Evaluation NOTE: QA AND QC ARE USED INTERCHANGABLY IN APPLETON AND LANGE

  2. Intensifying screen(ref: pg 59 Mosby, 190 Bushong) • Base • Reflective layer • Active Layer • Protective layer

  3. 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

  4. 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

  5. TARGET ANGLELINE FOCUS PRINCIPLEPG. 40 i-n, Mosby • Actual • Effective • Large angle • small angle • anode heel

  6. MAMMOGRAPHY • Use very low KVP 23-28 • molybdenum targets • High MAS

  7. PROCESSINGPG. 62 MOSBY,180 Bushong

  8. DEFINE • EXIT (REMNANT RADIATION) • LATENT IMAGE • MANIFEST IMAGE

  9. 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

  10. 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

  11. Detail • Focal spot size • Screen speed • SID • OID • Motion artifact

  12. CONTRAST • KVP • GRID • FIELD SIZE • Filtration • Anatomy and pathology • HIGH, SHORT • LOW, LONG

  13. CHARACTERISTIC/H&D CURVE PG 58 MOSBY • Exposure error latitude • Contrast latitude • speed of film • base/fog • processing

  14. DIFFERENTIAL ABSORPTION & ATTENUATION • Difference between x-rays absorbed through photoelectric effect and those not absorbed at all.

  15. Quantum Mottle • Mottled appearance (looking through a mist) • low mas-increase QM • high speed film- increase QM

  16. GRIDS • GRID RATIO: HEIGHT DIVIDED BY DISTANCE • AFFECT ON CONTRAST • MULTIPLYING FACTOR • GRID CUTOFF

  17. 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

  18. FILM CONSTRUCTION (Pg. 166-167 Bushong)/Cassette • BASE • EMULSION

  19. CHARACTERISTIC COMPTON INFRARED CLASSICAL, THOMSON, COHERENT PHOTOELECTRIC BREMSTRAULING PAIR PRODUCTION PHOTO-DISINTEGRATION INTERACTIONS

  20. Technique and Exposure