Exam 2- Factors selected at control panel

Question 1

mA-

Answer 1

quantity of electrical current flowing in a circuit

Question 2

cathode contains-

Answer 2

filament

Question 3

when current is applied to the filament circuit-

Answer 3

-flow through filament
-heat up filament circuit
-electrons will be boiled off

Question 4

filament-

Answer 4

coil of wire where electrons are going to be boiled off

Question 5

Thermionic emission-

Answer 5

boiling off of electrons at filament

Question 6

focusing cup-

Answer 6

place on cathode where electrons are boiled off of filament & held in place

Question 7

space charge/electron cloud-

Answer 7

collection of electrons boiled off filament in focusing cup

Question 8

the lower the mA-

Answer 8

the lower quantity/amount of electrons boiling off the filament

Question 9

as more circuit is applied to the filament, the circuit-

Answer 9

gets hotter

Question 10

intensity/quantity of the x-ray beam is directly proportional to-

Answer 10

mA

Question 11

exposure time-

Answer 11

amount of time in which beam is activated & exposure occurs

Question 12

when using a breathing technique, use a _____ exposure time-

Answer 12

longer

Question 13

want exposure time as short as possible to-

Answer 13

eliminate motion

Question 14

2 types of motion-

Answer 14

voluntary & involuntary

Question 15

eliminate voluntary motion-

Answer 15

good patient instructions

Question 16

eliminate involuntary motion-

Answer 16

-short exposure time
-immobilization devices

Question 17

mAs-

Answer 17

total quantity of x-rays produced at exposure

Question 18

penumbra-

Answer 18

blur

Question 19

mA directly proportional to-

Answer 19

beam intensity & exposure

Question 20

time/exposure time directly proportional to-

Answer 20

quantity/intensity/exposure of x-rays produced bec it is directly proportional to electrons

Question 21

mAs directly proportional to-

Answer 21

receptor exposure

Question 22

quantum model referred to as-

Answer 22

mottle

Question 23

causes mottle to appear on radiograph-

Answer 23

insufficient exposure/mA, s, or mAs

Question 24

mottle-

Answer 24

grainy appearance in image

Question 25

low exposure (low mA & short exposure time) results in-

Answer 25

mottle

Question 26

exposure index-

Answer 26

when you make an exposure & a # pops up it represents the amt. of exposure to IR

Question 27

exposure index ranges-

Answer 27

1500-1700

Question 28

law of reciprocity-

Answer 28

states as long as product remains the same, mA & time can be altered & still produce same total exposure (mAs)

Question 29

mA, s, or mAs increases-

Answer 29

receptor exposure (they're directly proportional

Question 30

kVp-

Answer 30

measure of force behind a current of electricity that causes it to flow

Question 31

direction of electron flow-

Answer 31

when potential diff. in x-ray tube, electrons flow from C(-)–A (+) side

Question 32

kVp determines-

Answer 32

how fast electrons will travel from cathode side to anode side

Question 33

kV-

Answer 33

measures quality of x-rays produced at exposure

Question 34

higher energy electrons result in-

Answer 34

higher energy x-ray photons that will be more penetrating

Question 35

kVp affects-

Answer 35

quantity of x-ray beam bec higher energy electrons have more interactions at anode & produce more x-ray photons

Question 36

higher energy electrons have-

Answer 36

more energy @ anode & produce more x-ray photons

Question 37

2 types of x-rays produced-

Answer 37

Brimstrung & Characteristic

Question 38

high kVp is used for-

Answer 38

thicker parts (chest)

Question 39

w: low energy you're going to have-

Answer 39

higher contrast between adjacent structures

Question 40

scale of contrast refers to-

Answer 40

the entire image

Question 41

interactions w: matter-

Answer 41

1.) Compton Scattering/Effect 2.) Coherent Scattering 3.) Photoelectric Effect 4.) Pairproduction 5.) Photodisintegration 6.) X-ray photon

Question 42

interactions w: matter that occur in diagnostic range (3)-

Answer 42

1.) Compton Scattering/Effect 2.) Coherent Scattering 3.) Photoelectric Effect

Question 43

compton scatter/effect-

Answer 43

interactions account for 99% of scatter that reaches IR

Question 44

photoelectric effect-

Answer 44

-x-ray photon is completely absorbed & doesn’t reach IR -results in subj. contrast in img

Question 45

____ & ____ primarily affect img. quality-

Answer 45

compton & PE

Question 46

kVp increases, what decreases-

Answer 46

photoelectric effect decreases & produces more Compton scattering

Question 47

scatter-

Answer 47

-unwanted exposure -should use a grid to reduce it -also called fog sometimes

Question 48

kVp increases, any scatter produced x-ray photons will have-

Answer 48

higher energy produced

Question 49

if scattered photons have a higher energy-

Answer 49

it is more likely to penetrate patient & go straight to IR

Question 50

3 ways increasing the kVp can increase receptor exposure-

Answer 50

1.) quantity of x-rays will also increase because of interactions at anode 2.) x-ray photons with higher energy are more likely to penetrate through patient & get to IR 3.) energy of Compton Scattering is more likely to increase/have higher energy & penetrate patient & strike IR

Question 51

minimum kVp required to-

Answer 51

-penetrate anatomy of interest adequately -produce desired scale of contrast

Question 52

kVp that is too low will not-

Answer 52

penetrate anatomy & increase patient dose

Question 53

higher kVp reduces-

Answer 53

patient dose because as kVp increases, mAs can decrease

Question 54

optimal kVp-

Answer 54

setting will be similar, but vary among manufacturer’s processing systems

Question 55

If kVp doesn’t penetrate part (too low), what will result for that?

Answer 55

Insufficient exposure to IR (MOTTLE IN IMAGE)

Question 56

If you use a kVp that is too hot/high, what will happen to image?

Answer 56

Darker because it’s over-penetrating part

Question 57

wide exposure latitude-

Answer 57

-increased kVp, wider exposure latitude -Optimal kVp for proj. may be 100, w: range of 95-105

Question 58

Narrow Exposure Latitude-

Answer 58

-decreased kVp, narrow exposure latitude -Optimal kVp for proj. may be 52, w; range of 50-54

Question 59

if the kVp is too penetrating-

Answer 59

more of the beam will penetrate the anatomy than it should, thus increasing receptor exposure

Question 60

too much receptor exposure from excessive kVp-

Answer 60

negatively affects image quality

Question 61

increasing kVp by 15% change will-

Answer 61

double receptor exposure

Question 62

increase kVp by 15% to maintain-

Answer 62

RE, cut your mAs in half

Question 63

kVp increases-

Answer 63

receptor exposure

Question 64

kVp decreases-

Answer 64

contrast

Question 65

no practical amount of mAs can compensate-

Answer 65

for insufficient kVp

Question 66

purpose of AEC-

Answer 66

produce more consistent exposure & reduce repeats

Question 67

optimum mA-

Answer 67

maximum mA setting for a given focal spot size, which doesn’t overload anodes capacity

Question 68

AEC acts as-

Answer 68

back up timer when exposure is made

Question 69

AEC location-

Answer 69

after the patient, but before the IR

Question 70

density control setting-

Answer 70

-each setting represents 25% change in beam intensity -N- means normal, could be from 1-8 & -1 to -8

Question 71

mAs readout-

Answer 71

when mA is set & use AEC, the AEC will multiply mA by AEC time & get mAs readout

Question 72

limitations of AEC (4)-

Answer 72

1.) anatomy must completely cover detector 2.) detector must be covered with anatomy of interest 3.) failure to collimate will result in more scatter production 4.) AEC shouldn’t be used if prosthetic/surgical device over detector

Question 73

APR-

Answer 73

preset technical factors

Question 74

APR allows tech. to-

Answer 74

choose exam & utilizes electronically stored technical factors

Question 75

2 types of technique charts-

Answer 75

-fixed kVp -variable kVp

Question 76

fixed kVp-

Answer 76

uses optimal kVp for that body part & mAs varies depending on part thickness

Question 77

variable kVp-

Answer 77

kVp changes with part thickness & mAs remains constant

Question 78

if you change the kVp, kVp varies by-

Answer 78

2 for every cm of part thickness

Question 79

exposure standardization-

Answer 79

elimination of variation as much as possible in as many as possible factors which affect optimum exposure time

Question 80

exposure standardization reduces-

Answer 80

patient exposure