Week 10 - Photographic Properties

Question 1

Defined by brightness and density, visible result of an IRs response to an exposure

Answer 1

Brightness

Question 2

Differences between brightness levels and densities, differentiates anatomic tissue

Answer 2

Contrast

Question 3

What two factors affect radiographic visibility?

Answer 3

Brightness and contrast

Question 4

T/F
Brightness is not related to IR exposure

Answer 4

True

Question 5

Digital post process that produces changes in brightness

Answer 5

Window level

Question 6

What is brightness controlled by?

Answer 6

The look up table (LUT)

Question 7

Term used to reflect exposure to the radiographic film - the viewable result of a films response to exposure

Answer 7

Density

Question 8

What term is interchangeable with density?

Answer 8

IR exposure

Question 9

What is shown by an area of increased brightness on a monitor?

Answer 9

Decreased density on image

Question 10

What is shown by an area of decreased brightness on a monitor?

Answer 10

Increased density on the image

Question 11

ROI

Answer 11

Anatomic structures of interest

Question 12

T/F
mAs is directly proportional to IR exposure

Answer 12

True

Question 13

Numerical value that compares data from many images (accurately exposed images)

Answer 13

EXI values (exposure index)

Question 14

Intensity is inversely proportional to the square of the distance

Answer 14

Inverse square law

Question 15

T/F
For every 4-5cm of thickness, mAs should be adjusted by a factor of 2

Answer 15

True
*4-5cm attenuate 50%

Question 16

How do grids affect exposure?

Answer 16

Use of a grid will reduce scatter reaching the IR, thereby reducing density/exposure

Question 17

A photographic property that affects the visibility of recorded detail

Answer 17

Radiographic contrast

Question 18

T/F
Any change that affects density will affect contrast

Answer 18

True

Question 19

Fewer discernible shades of gray

Answer 19

High contrast

Question 20

More discernible shades of grey

Answer 20

Low contrast

Question 21

Fewer shades of grey levels wity greater differences between them

Answer 21

High contrast

Question 22

Many shades of grey levels with few differences between them

Answer 22

Low contrast

Question 23

What controlling factor Results in fewer density differences in the anatomic tissue (low/long scale contrast)

Answer 23

High kVp

Question 24

What controlling factor results in greater density differences in the tissue (high/short scale contrast)

Answer 24

Low kvp

Question 25

T/F
The possibility of the focal spot size altering contrast enough to be visible is extremely unlikely

Answer 25

True

Question 26

Contrast with high atomic number; appear more radiopaque

Answer 26

Positive contrast agent

Question 27

Contrast gases with low density appearing radiolucent

Answer 27

Negative contrast agent

Question 28

Tool to help focus on contrast in selected area, by eliminating adjacent information

Answer 28

Contrast mask

Question 29

Allows for adjustments to image brightness and contrast. This process involves the creation of a histogram and the application of the look-up table and windowing

Answer 29

Grayscale processing

Question 30

Insufficient number of incoming xray photons reaching the image receptor

Answer 30

Quantum noise

Question 31

T/F
The fewer the photons reaching the IR to form the image, the greater the quantum noise visible on the digital image

Answer 31

True

Question 32

T/F
Increased noise decreases image contrast

Answer 32

True

Question 33

Artifacts greater in density than the surrounding area immediately surrounding them

Answer 33

Plus density artifacts

Question 34

Artifacts lower in density than the area immediately surrounding them

Answer 34

Minus density artifacts