Rules

Question 1

How do you adjust the radiograph if it’s too dark but the structures are visible?

Answer 1

Decrease kV 15% OR decrease mAs 50% (50% mAs rule)

Question 2

How do you adjust the radiograph if it’s too light and the structures are visible?

Answer 2

Increase kV 15% OR increase mAs 2x

Question 3

How do you adjust the radiograph if it’s too dark and the structures are not visible?

Answer 3

Decrease kV 15% AND increase mAs 50% (50% mAs rule)

Question 4

Optimal kV range for cervical spine?

Answer 4

75-85 kV

Question 5

Optimal kV range for AP thoracic?

Answer 5

75-85 kV

Question 6

Optimal kV range for lateral thoracic?

Answer 6

85-95 kV

Question 7

Optimal kV range for AP lumbar?

Answer 7

80-90 kV

Question 8

Optimal kV range for lateral lumbar?

Answer 8

85-95 kV

Question 9

Optimal range for AP full spine?

Answer 9

80-100 kV

Question 10

Optimal kV range for pelvis/hip?

Answer 10

75-85 kV

Question 11

What’s the significance of mAs?

Answer 11

It controls film density

Question 12

What is the reciprocal rule?

Answer 12

Doubling the mAs doubles density of the film

Question 13

What increases the density of the film 2x?

Answer 13

Increase kV 15%

Question 14

What cuts the film density in half?

Answer 14

Decrease kV 15%

Question 15

High contrast is also known as…

Answer 15

Short scale (black/white with few shades of gray)

Question 16

Low contrast is also known as…

Answer 16

Long scale (many shades of gray)

Question 17

If film is too dark or light but still shows structures…

Answer 17

Use 15% rule

Question 18

If film is too gray but density is good…

Answer 18

Decrease kV 15% AND double mAs

Question 19

If film does not have enough gray but density is good…

Answer 19

Increase kV 15% AND cut mAs 50%

Question 20

How do you adjust the radiograph if it’s too light and the structures are not visible?

Answer 20

Increase kV 15% AND increase mAs 2x

Question 21

If density is good but film does not have enough gray…

Answer 21

Increase kV 15% and decrease mAs 50%

Question 22

If density of the film is good but is too gray…

Answer 22

Decrease kV 15% AND increase mAs 2x

Question 23

In order to make a long scale film (gray) look like a short scale film…

Answer 23

Decrease kV 15% and increase MAs 2x (double it)

Question 24

Underexposed versus long scale…

Answer 24

Underexposed is too light and fuzzy

Question 25

Overexposed versus long scale…

Answer 25

Overexposed is splotchy, some parts are too white and some too dark

Question 26

Slight change, if film is slightly too dark compared to slightly lighter film…

Answer 26

Darker film has 30% more mAs
Lighter film has 30% less mAs
*30% rule

Question 27

What two densities make up the Cornu of the thyroid cartilage (on lateral cervical)

Answer 27

Water

Calcium

Question 28

How do we make the film look better if its gray and fuzzy? (Kvp is set at 80 for cervical)

Answer 28

Double mAs

Question 29

What is dark on the ilia on an AP pelvic? What natural densities makes it up?

Answer 29

Gas/air

Air makes it up

Question 30

Why do we see rib cartilages?

Answer 30

Water and natural metal

Question 31

In order to make a short scale film look like a long scale film…

Answer 31

Increase kV 15% AND cut mAs 50%