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

Digital Imaging

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

TARGET ANGLE

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

MAMMOGRAPHY

Use very low KVP 23-28 molybdenum targets High MAS

PROCESSINGPG. 62 MOSBY,180 Bushong

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

INTERACTIONS

CHARACTERISTIC COMPTON INFRARED CLASSICAL,

THOMSON, COHERENT

PHOTOELECTRIC BREMSTRAULING PAIR

PRODUCTION PHOTO-

DISINTEGRATION

Technique and Exposure