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Image Production and Evaluation
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 phosphor: less detail and more speed
Formula: old screen
new screen
Intensifying screen and density
More mAs for which type of screen system: slow or fast?
Spectral matching
A/L #’s11,35, 42, 59, 74, 84, 89, 91, 104,121,128,129, 133,
134, 182, 184
Digital Imaging
MOSBY pg 59-73
PSP,CRT, ADC, IP,CR, DR,
FOV- field of view or how much of patient is included in the matrix
Matrix- rows and columns of pixels (512 x 512)
Pixel size
As Matrix increases, pixel size decreases
As FOV increases, pixel size increases
As pixel size increases, resolution decreases
Voxel
Window width vs. window level
a-Si vs. a-Se
DQE (see handout)
TFT
Mosby ?’s 1-8 pg
TARGET ANGLE
LINE FOCUS PRINCIPLE
PG. 40 i-n, Mosby
Actual
Effective
Large angle
small angle
anode heel
#34,51,53,80,94, 110,106, 135, 223
MAMMOGRAPHY
Use very low KVP 23-28
molybdenum targets- To produce “soft radiation”
Very little filtration-why?
High mAs
DXA
Evaluates bone mass density (BMD)
Two photon energies high for bone, low for soft tissue
# 8,117,126, #127, 188
PROCESSING/Darkroom
PG. 62 MOSBY,180 Bushong
#’s 4,12, 26, 37,62,67,68,83,92,98,
108,112,120, 122,142,149,165, 167,173,212,234, 247
DEFINE
EXIT (REMNANT RADIATION)
LATENT IMAGE
MANIFEST IMAGE
#4,
Magnification: FOR EVERY 1" OF OID INCREASE, SID MUST
INCREASE BY 7"
Mag. Factor - SID
SOD
SOD ---- SID - OID
IMAGE SIZE -image = SID
object SOD
% OF MAG- OID
SOD X 100
#s 25,45 57,93, 159
DENSITY
OD or Logarithm of opacity
Ratio of amount of light incident on film to the amount of light
transmitted thru film (Mosby, pg. 85)
Controlling factors
mAs
kVP
Distance
Film/screen
Grids
Collimation
Anatomy/pathology
Anode Heel
Filtration
# 13,14, 17,27,47,52,58,85,86,118,136, 139, 171
Detail
Focal spot size
Screen speed
SID
OID
Motion artifact
#s 49,65, 70,124,140,145
CONTRAST
KVP
GRID
FIELD SIZE
Filtration
Anatomy and pathology
HIGH, SHORT
LOW, LONG
# 46,54, 60,73,96,143,146,164, 200,221
CHARACTERISTIC/H&D CURVE PG 91 MOSBY
Exposure error latitude
Contrast latitude
speed of film
base/fog
processing
#’s9,21,55,66, 109, 115, 138,153, 157,162,172, 194
DIFFERENTIAL ABSORPTION & ATTENUATION
Difference between x-rays absorbed through photoelectric
effect and those not absorbed at all.
#’s 39, 169
Quantum Mottle
Mottled appearance (looking through a mist)
low mAs-increase QM
high speed film- increase QM
#’s 107, 123
GRIDS
GRID RATIO: HEIGHT DIVIDED BY DISTANCE
AFFECT ON CONTRAST
MULTIPLYING FACTOR
GRID CUTOFF
#’s6,20, 32,44,69,78 ,87,137, 147, 154, 156, 179
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
# 80,106
FILM CONSTRUCTION (Pg. 166-167 Bushong)/Cassette
BASE
EMULSION
Laser film- sensitive to most safelights. Should be handled in
total darkness
#’s 26,28, 43, 150, 166,185, 206
AEC (Equipment Operation and Maintenance pg. 291 #110)
Photomultiplier tube
Ion Chamber
#1, 16,33,100
Technique and Exposure
#5, 8, 23,27, 30, 50 72,73, 77, 85,103,114, 119, 151,170,
178,197, 209,227 , 155, 161
INTERACTIONS
CHARACTERISTIC
COMPTON
INFRARED
CLASSICAL,
THOMSON, COHERENT
PHOTOELECTRIC
BREMSTRAULING
PAIR PRODUCTION
PHOTO-DISINTEGRATION
#’s 176,
Misc
#10, 29, 38, 41, 48, 63, 64,75, 76, 81, 82, 90, 95, 97, 99, 101, 102,
105, 111, 113, 116, 125, 129, 130, 132, 141, 148, 152, 158, 160, 163,
174, 175, 177, 180, 181,183, 186, 187, 189, 190,191,192, 193, 195,
196,197, 198,199