RADIOGRAPHIC QUALITY HIGH YIELD

Question 1

what are the two types of resolution?

Answer 1

contrast

spatial

Question 2

what is the equation for optical density?

Answer 2

log 10(Io/Ii)

Io- light intensity incident on film

Ii- light transmitted through film

Question 3

how is optical density measured? ranges?

Answer 3

densitometer

normal range- 0.3-2
above 2.2 needs a hot light

Question 4

percent light transmittance is inversely proportional to _____?

Answer 4

optical density

Question 5

as %T (light transmittance) decreases, what increases?

Answer 5

optical density

Question 6

0.3 OD is how much transmittance?

Answer 6

50%

Question 7

2.0 ID is how much transmittance?

Answer 7

`1%

Question 8

in relation to characteristic film curve what is the relation of exposure vs optical density? if there is a 0.3 increase in OD what does that mean for exposure?

Answer 8

directly proportional

2x increase in exposure

Question 9

increased slope is equal to increased _____?

Answer 9

film contrast

Question 10

a wide latitude, a component of characteristic film curve, affects mAs how?

Answer 10

more variation, however a greater margin for error

inversely related to film contrast

Question 11

what are the two things controlled through windowing?

Answer 11

window level (density)

window width (contrast)

Question 12

what are the two types of radiographic contrast?

Answer 12

film contrast

subject contrast

Question 13

subject contrast is due to _____? (4 things)

Answer 13

body part thickness

density differences

atomic number differences

quality of radiation

Question 14

for quality of radiation, what does high kVp mean for contrast?

Answer 14

decreased contrast

Question 15

for quality of radiation, what does low kVp mean for contrast?

does changing mAs have any affect on contrast?

Answer 15

increased contrast

none

Question 16

what can cause film fog?

Answer 16

temps >68 degree F
high humidity
too much time or temp in process
safelights
film age
background radiation

Question 17

what are the causes for scatter radiation?

Answer 17

increased part thickness

increased field size

increased kVp of x-rays