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

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Presentation on theme: "Image Production and Evaluation NOTE: QA AND QC ARE USED INTERCHANGABLY IN APPLETON AND LANGE."— Presentation transcript:

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) n Base n Reflective layer n Active Layer n Protective layer

3 Intensifying.Screen: Detail and speed n Thicker the active layer: less detail and more speed n Larger the phospher:less detail and more speed n Formula: old screen new screen

4 Digital Imaging n PSP n CRT n ADC n IP n CR n DR n FOV field of view or how much of the patient is included in the matrix n Matrix-rows and columns of pixels (512 x512) n Pixel size –As matrix increase, pixel size decreases –As FOV increases, pixel size increases –As pixel size increases, resolutions decreases

5 TARGET ANGLE LINE FOCUS PRINCIPLE PG. 40 i-n, Mosby n Actual n Effective n Large angle n small angle n anode heel

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

7 PROCESSING PG. 62 MOSBY,180 Bushong

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9 DEFINE n EXIT (REMNANT RADIATION) n LATENT IMAGE n MANIFEST IMAGE

10 Magnification: FOR EVERY 1” OF OID INCREASE, SID MUST INCREASE BY 7” WALLACE PG 27-33 n Mag. Factor - SID SOD n SOD ---- SID - OID n IMAGE SIZE -image = SID object SOD n % OF MAG- OID SOD X 100 n #s 25,45 57,87,93

11 DENSITY n OD or Logarithm of opacity n Ratio of amount of light incident on film to the amount of light transmitted thru film (Mosby, pg. 53) n Controlling factors –mAs –kVP –Distance –Film/screen –Grids –Collimation –Anatomy/pathology –Anode Heel –Filtration

12 Detail n Focal spot size n Screen speed n SID n OID n Motion artifact

13 CONTRAST n KVP n GRID n FIELD SIZE n Filtration n Anatomy and pathology n HIGH, SHORT n LOW, LONG

14 CHARACTERISTIC/H&D CURVE PG 58 MOSBY n Exposure error latitude n Contrast latitude n speed of film n base/fog n processing

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

16 Quantum Mottle n Mottled appearance (looking through a mist) n low mas-increase QM n high speed film- increase QM

17 GRIDS n GRID RATIO: HEIGHT DIVIDED BY DISTANCE n AFFECT ON CONTRAST n MULTIPLYING FACTOR n GRID CUTOFF

18 FOCAL SPOT/ BLUR n Umbra/penumbra or focal spot blur n Small FS = less n Large FS = more n Increased SID = less n decreased SID = more n increased OID = more n decreased OID = less

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20 FILM CONSTRUCTION (Pg. 166-167 Bushong)/Cassette n BASE n EMULSION

21 INTERACTIONS n CHARACTERISTIC n COMPTON n INFRARED n CLASSICAL, THOMSON, COHERENT n PHOTOELECTRIC n BREMSTRAULING n PAIR PRODUCTION n PHOTO- DISINTEGRATION

22 Technique and Exposure


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