exam 2

Question 1

____ kV creates ____ contrast

Answer 1

low, high

Question 2

____ anatomy requires a ____ kVp

Answer 2

thinner, lower

Question 3

responsible for subject contrast

Answer 3

photoelectric effect

Question 4

how much of scatter is compton

Answer 4

99%

Question 5

an _____ in kVp results in a ____ in compton scattering and a _____ in image contrast

Answer 5

increase, increase, decrease

Question 6

_____ kVp results in a _____ scale of contrast

Answer 6

low, short

Question 7

an _____ in kVp allows a _____ in mAs

Answer 7

increase, decrease

Question 8

lower kVp setting allows for a _____

Answer 8

narrow exposure latitude

Question 9

the measure of the electrical force behind a current of electricity which causes it to flow

Answer 9

kV

Question 10

peak kilovoltage in the xray beam

Answer 10

kVp

Question 11

how do the electrons flow in the xray tube

Answer 11

cathode to anode

Question 12

the ____ the kVp, the _____ the force

Answer 12

higher, higher

Question 13

_____ determines the quality of the xray beam/ xrays produced at the exposure

Answer 13

kVp

Question 14

visible difference between any 2 selected structures or brightness levels

Answer 14

contrast

Question 15

when considerable or major differences between gray shades are present (high contrast), but the total number of shades of gray is small

Answer 15

short scale

Question 16

slight differences between shades of gray is present (low contrast), but the total number of shades of gray is great

Answer 16

long scale

Question 17

____ anatomy requires a ____ kVp (2)

Answer 17

thicker, higher

Question 18

x-ray photons are absorbed by the body part because x-ray photon has lower energy

Answer 18

photoelectric absorption

Question 19

when incoming x-ray photon energy is higher than the outer shell energy it strikes, resulting in injection of electron from outer shell; remaining energy is the scattered photon

Answer 19

compton scattering

Question 20

unwanted exposure

Answer 20

scatter

Question 21

as kVp ____, compton scattering _____, and photoelectric absorption _____

Answer 21

increases, increases, decreases

Question 22

the minimum kVp required to penetrate the anatomy of interest adequately and produce the desired scale of contrast

Answer 22

optimal kVp

Question 23

negative side of the tube

Answer 23

cathode

Question 24

positive side of the tube

Answer 24

anode

Question 25

an ____- in kVp creates an ____ in receptor exposure

Answer 25

increase, increase

Question 26

a beam with a lower penetrability due to low kVp may penetrate just _____

Answer 26

soft tissue

Question 27

scatter results in a veiling layer of exposure called ____

Answer 27

fog

Question 28

any unwanted information on an image that interferes with visibility of the object of interest

Answer 28

noise

Question 29

higher energy photons are more likely to result in ______

Answer 29

compton scattering

Question 30

an _____ in kVp causes a _____ in patient dose

Answer 30

increase, decrease

Question 31

range of exposures that produces quality images at appropriate patient dose

Answer 31

exposure latitude

Question 32

a higher kVp causes a _____

Answer 32

wide exposure latitude

Question 33

what rule says that a 15% change in kVp will change the exposure by a factor of 2

Answer 33

15% rule

Question 34

if you increase kVp by 15% you have to _____ to maintain receptor exposure

Answer 34

half the mAs

Question 35

if you decrease kVp by 15%, you have to _____ to maintain receptor exposure

Answer 35

double the mAs

Question 36

no practical amount of _____ can compensate for insufficient ____

Answer 36

mAs, kVp

Question 37

what 3 things does kVp affect

Answer 37

receptor exposure, contrast, noise

Question 38

automatic exposure control; purpose is to produce more consistent exposures and reduce repeats

Answer 38

AEC

Question 39

what are other names for an AEC

Answer 39

phototimer, photocell, and ion chamber

Question 40

what are factors set by the tech

Answer 40

kVp, mAs, AEC, and bucky

Question 41

maximum mA setting for a given focal spot size which does not overload the x-ray tube

Answer 41

optimal mA

Question 42

prevents over exposure of the patient when the AEC device fails to detect the appropriate amount of exposure

Answer 42

back up timer

Question 43

each increment results in a 25% change in the beam intensity; set to N for every exam normally

Answer 43

density control setting

Question 44

the actual amount of mAs used for that image is displayed immediately after the exposure

Answer 44

mAs readout

Question 45

1. the anatomy must cover the AEC 2. the anatomy of interest must cover the AEC 3. proper positioning/centering 4. proper collimation 5. AEC not used if patient has prosthetic or surgical devices

Answer 45

rules for using AEC

Question 46

anatomically programmed radiography; allows the tech to choose an exam that utilizes present technical factors

Answer 46

APR

Question 47

setting the mAs and kVp manually

Answer 47

manual tech facts

Question 48

an ____ in mA allows for a ____ in time

Answer 48

increase, decrease

Question 49

radiography units are preset with back up timers of ______

Answer 49

1-2 seconds

Question 50

what are the AEC cells

Answer 50

2 outer and one center cell