Rad Science contrast

Question 1

one of the 2 properties that make visibility of detail (photographic factor)

Answer 1

contrast

Question 2

contrast is the difference between

Answer 2

adjacent densities

Question 3

_contrast
few shades of grey
low kV
short scale
narrow latitude

Answer 3

High

Question 4

_contrast
many shades of gray
high kV
long scale
wide latitude

Answer 4

low

Question 5

what is the controlling factor of contrast

Answer 5

kV

Question 6

kV and contrast have an _ relationship

Answer 6

indirect

Question 7

as kV increases, contrast

Answer 7

decreases

Question 8

_controls the amount of scatter produced. Increasing _ increases the possibility of scatter, decreasing contrast

Answer 8

kV

kV

Question 9

increasing _ increases the average energy of the beam

Answer 9

kV

Question 10

increasing _ increases more uniform penetration of parts by the shorter wavelength x-rays

Answer 10

kV

Question 11

increasing _ increases the potential difference

Answer 11

kV

Question 12

compton /scatter is what color

Answer 12

grey

Question 13

PE is what color

Answer 13

white

Question 14

increasing OID= better

Answer 14

contrast

Question 15

distance- _ affects density using the air-gap technique. As your _ increases, there is less chance of scatter reaching the IR increasing

Answer 15

OID

OID

Question 16

what changes the average energy of the beam

Answer 16

filtration

Question 17

filtration makes the beam more

Answer 17

homogenous

Question 18

raising the average energy is the same as raising the _ which raises the chance for compton interactions, thus reducing contrast

Answer 18

kV

Question 19

collimating reduces the amount of tissue being irradiated, reducing the amount of Compton interactions possible, increasing contrast

Answer 19

beam restriction

Question 20

as the part size increases, more chances for compton interactions, increasing scatter, reducing

Answer 20

contrast

Question 21

additive diseases will _ subject contrast and increase radiographic contrast

Answer 21

increase

Question 22

what removes scatter before it reaches the IR, improving contrast

Answer 22

grids

Question 23

contrast improvement factor

Answer 23

k= contrast w/grid
——————-
contrast w/out grid

Question 24

Grid ratio=

Answer 24

D

Question 25

what is the formula for contrast improvement

Answer 25

k= contrast w/grid ------------------ contrast w/out grid

Question 26

as kV increases, contrast

Answer 26

decreases

Question 27

as OID increases, contrast

Answer 27

increases

Question 28

as grid ratio decreases, contrast

Answer 28

decreases

Question 29

as filtration decreases, contrast

Answer 29

increases

Question 30

as collimation decreases, contrast

Answer 30

decreases

Question 31

as patient size increases, contrast

Answer 31

decreases

Question 32

degree of geometrical sharpness or accuracy of the structural lines actually recorded on the image

Answer 32

detail

Question 33

Detail is also known as

Answer 33

definition sharpness spatial resolution recorded detail

Question 34

unit of resolution is

Answer 34

line pairs per millimeter

Question 35

there is always some loss of _ on all images

Answer 35

detail (sharpness)

Question 36

``` for optimal detail eliminate reduce reduce reduce Increase ```

Answer 36

``` motion OID focal spot size intensifying screen, phosphor size & concentration SID ```

Question 37

factors affecting recorded detail and formula

Answer 37

Distance | SOD =OID=SID

Question 38

OID decreases, detail

Answer 38

increases

Question 39

SID increases, detail

Answer 39

increases

Question 40

use a large _ to compensate for a large OID ex; C-spine

Answer 40

SID

Question 41

sharp shadow around object

Answer 41

umbra

Question 42

unsharp shadow around object (focal spot blur)

Answer 42

penumbra

Question 43

as focal spot size increases, penumbra _, detail _

Answer 43

increases | decreases

Question 44

as film/screen speed is decreased, detail

Answer 44

increases

Question 45

as film/screen speed increases, detail

Answer 45

decreases

Question 46

if the total # of incident photons reaching the intensifying screen are insufficient to activate enough phosphors to emit light over the entire radiograph

Answer 46

quantum mottle

Question 47

quantum mottle is caused by low

Answer 47

mAs

Question 48

_ is the only way to fix quantum mottle; grainy appearance

Answer 48

mAs

Question 49

There must be good contact between the film and intensifying screen. Poor contact makes bad resolution. Cassette must be discarded

Answer 49

wire mesh test

Question 50

3 types of motion

Answer 50

pt. motion tube motion excessive reciprocating grid motion

Question 51

voluntary motion (breathing) can best be controlled by

Answer 51

communication

Question 52

Involuntary motion (peristalsis, heartbeat) can be best controlled by a _ and _ to maintain density

Answer 52

short exposure time | increased mA

Question 53

as motion decreases, detail

Answer 53

increases

Question 54

as OID increases, detail

Answer 54

decreases

Question 55

as SID decreases, detail

Answer 55

decreases

Question 56

as focal spot size decreases, detail

Answer 56

increases

Question 57

as phosphor size increases, detail

Answer 57

decreases

Question 58

as film/screen speed decreases, detail

Answer 58

increases

Question 59

misrepresentation of the size or shape of the structures being examined

Answer 59

distortion

Question 60

2 kinds of distortion

Answer 60

size-mag. OID/SID | shape-elongation/foreshortening

Question 61

as size magnification decreases, detail

Answer 61

increases

Question 62

to minimize size distortion, max. _ and min. _

Answer 62

SID | OID

Question 63

as SID increases, distortion

Answer 63

decreases

Question 64

as OID decreases, distortion

Answer 64

decreases

Question 65

shape distortion can be

Answer 65

elongation | forshortening

Question 66

elongation is caused by the

Answer 66

tube or IR improperly aligned

Question 67

foreshortening is caused by the

Answer 67

prt. being improperly aligned

Question 68

The CR should be _ to the part and IR

Answer 68

perpendicular

Question 69

The CR is the only portion of the beam w/out

Answer 69

shape distortion

Question 70

as SID decreases, distortion

Answer 70

increases

Question 71

as OID decreases, distortion

Answer 71

decreases

Question 72

as tube alignment decreases, distortion

Answer 72

increases

Question 73

as IR alignment increases, distortion

Answer 73

decreases

Question 74

as part alignment increases, distortion

Answer 74

decreases