Midterm 2 - Memorize

Question 1

How do you double density (2)

Answer 1

Double mAs

Increase kVp 15%

Question 2

Double mAs and you

Answer 2

double density

Question 3

Increase SID and you

Answer 3

reduce beam intensity

Question 4

Increase kVp 15% and you

Answer 4

Double image density; lower contrast

Question 5

Minimize scatter (5)

Answer 5

Grid 
Air gap technique = to 8:1 grid
Minimize volume of tissue (collimating)
Decrease kVp
Decrease mAs

Question 6

Air gap technique equal to what kind of grid

Answer 6

8:1

Question 7

Things that increase scatter (3):

Answer 7

• more tissue volume
• more kVp
• more mAs

Question 8

Fog is caused by (6 - LA SHOT)

Answer 8

• light: safelight exposure, light leaks in dark room
• accidental radiation exposure
• scatter
• high film storage temp or pressure
• old film
• TTT: too much/not enough time, temp, titration or exposure to darkroom chemical fumes

Question 9

Increased film OR screen speed causes ___ and mean what about mAs?

Answer 9

More density

So less mAs needed to create density

Question 10

Usual value for gross fog index

Answer 10

0.15 to 0.20

Question 11

Faster films have higher/lower gross fog index

Answer 11

Higher

Gross fog index is Base plus Fog. Unexposed film will be 0.15-0.20. Faster films will be closer to 0.20 while slower films will be closer to 0.15

Question 12

The longer the toe of H&D curve, the more/less sensitive to fog the film is

Answer 12

Less

Question 13

Speed index is the step wedge strip that has the closest optical density to

Answer 13

1.0

Question 14

Contrast index step should be _____ for films used for skeletal images

Answer 14

1.4-1.7

Question 15

Gross fog index is

Answer 15

(Film) Base plus Fog

Question 16

Shoulder of the curve represents

Answer 16

D-max

Max optical density the film will achieve

Question 17

Body of the curve shows what? What does a high vertical rise vs a less steep slope mean?

Answer 17

Latitude

high slope: short latitude and high contrast film

LLL: Low slope: Long latitude and Low contrast film

Question 18

The H&D curve plots what and what?

Answer 18

Optical density (vertical)

Log relative exposure (horizontal)

Question 19

Changes in SID from 40 to 56” you want to multiply original mAs by

Answer 19

2

Question 20

Changes in SID from 40 to 80” you want to multiply original mAs by

Answer 20

4

Question 21

Changes in SID from 40 to 72” you want to multiply original mAs by

Answer 21

3

Question 22

mAs rule (equation)

Answer 22

mAs1 D1^2
———=————
mAs2 D2^2

Question 23

Inverse square law (equation)

Answer 23

I1 D2^2
——=———
12 D1^2

Question 24

What increases magnification (2)

Answer 24

Increased OID

Decreased SID

Question 25

Image sharpness is affected by (3)

Answer 25

FSS (focal spot size)
OID
SID

Question 26

Under-replenishment of automatic developer titration results in (2)

Answer 26

Loss of contrast

Loss of film density

Question 27

Densitometer reports on a scale of 0 to 4. O means what? 4 means what?

Answer 27

0 means 0% transmission through film

4 means 100% light transmission through film