brake test 3

Question 1

As part thickness increase both film density and contrast decrease (true false)

Answer 1

true

Question 2

What are the guidelines for selecting technical factors on an average patient tor a lateral abdomen or lumbar spine radiograph?

Answer 2

1. Double mAs used for AP abdomen or AP lumbar spine radiograph
2. increase by kV 15% for AP abdomen or lumbar spine radiograph

Question 3

negative contrast agents attenuate less than soft tissue because of lower atomic # (true-false)

Answer 3

False ( because of density)

Question 4

Positive contrast agents attenuate more than soft tissue and appear as areas of increased density on an image (true-false)

Answer 4

False ( increase brightness)

Question 5

An infant chest will have less contrast than an adult chest (true-false)

Answer 5

True

Question 6

To adapt exposure factors for a ten year old skull, it is recommended to use 15% less kVp used for adult patients (true-false)

Answer 6

False ( for infant 6 and under)

Question 7

increasing added filtration to the tube will increase the HVL (true/false)

Answer 7

True

Question 8

what is the effect of part thickness on radiographic density?

Answer 8

Makes >lighter, < film density and IR exposure

Question 9

what is the effect of part thickness on radiographic contrast?

Answer 9

Contrast <, More noise

Question 10

How is mAs adjusted to compensate for changes in part thickness

Answer 10

for every 4-5 cm in part thickness double mAs

Question 11

How does a technologist measure part thickness?

Answer 11

caliper

Question 12

compare the attenuation properties of positive contrast media with negative contrast agents.

Answer 12

Positive (Barium)- attenuate > than soft tissue & areas have > Z# = > brightness
Negative (Air)- attenuate < than soft tissue because < physical density = dark

Question 13

if the normal technical factors for a lateral c-spine are 18 mAs and 79 kVp, what technical factors would be used for a soft tissue lateral neck taken with a film IR?
What needs to be done with a digital IR

Answer 13

decrease kVp by 15% = 67kVp and 18mAs

nothing the algorithms or AEC will change it

Question 14

The normal technical factors for a AP angle are 10 mAs and 60 kVp. Based on the theory that wet casts attenuate differently than dry cast, what technical factors would be used if the ankle is in a full wet plaster cast?
What technical factors would be used if the ankle is in a full dry case?

Answer 14

wet cast = increase the kVp by 22% = 73kVp and 10mAs or increase mAs by 3X = 60kvp and 30mAs
dry cast = increase the mAs by 2X = 60kVp and 20 mAs or increase the kVp by 15% = 70kVp and 10 mAs

Question 15

The normal technical factors for a chest x-ray taken on inspiration are 115kVp and 6mAs. What technical factors should be used for a chest x-ray taken on expiration?

Answer 15

increase mAs by 30% = 115kVp and 8mAs

Question 16

a frail, elderly patient comes to the radiology department for a lumbar spine series. The history on the requisition states the patient has osteoporosis. The patient is average size but as the patient gets on the x-ray table, he complains of how hard the table is for him because he is just “skin and bone” with no body fat for cushioning. When you set your technical factors for the AP radiograph, you read the technique chart on the wall which state the average technique for an AP lumbar is 80kVp and 30mAs. What technical factors will you use?
Why?

Answer 16

reduce kVp by 15%

Because the elderly patient has less bone calcium, less fluid and osteoporosis is a destructive diseases of the bone.

Question 17

An impatient is sent to radiology for an obstructive series. The history on the requisition state the patient has ascites. The patient seems of average size but you notice when palpating for bony landmarks that the abdomen is tightly distended and very firm. You read the technique chart on the wall which states the average technique for a KUB is 80kVp and 30mAs. What technical factors will you use for this patient’s KUB?

Answer 17

increase mAs 25-50%
Because the patient is doing a KUB that’s basically air we would use mAs changes and the patient has ascites an additive disease

Question 18

an impatient is sent to radiology for an obstructive series. The history on the requisition state the patient has a bowel obstruction. The patient is average size but you notice when palpating for the iliac crest that the abdomen is tightly distended and very firm. You read the technique chart on the wall which state the average technique for a KUB is 80kVp and 30mAs. What technical factors will you use for this patient’s kUB

Answer 18

decrease the mAs by 25-50%

because it a destructive air disease

Question 19

with an average torso thickness of 22cm, technical factors for a portable chest are 75kVpp and 3mAs. What factors should be used if torso thickness is 26cm.

Answer 19

increase mAs by 2X= 75kVp and 6mAs

Question 20

the average adult torso thickness in the AP projection is 22cm. What is the average thickness for the lateral projection?

Answer 20

8cm thicker

Question 21

Technical factors for an AP lumbar spine are 85kVp and 32mAs. How should the technical factors be adjusted form the lateral lumbar spine?

Answer 21

increase mAs by 2X - 85kvp and 64mAs and increase kVp by 15% (10 rule) = 95kVp and 32mAs

Question 22

summarize the technical factor adjustments recommended for pediatric patients

Answer 22

lower (kVp and mAs) and shorter exposure time to eliminate motion

Question 23

List the order of greatest attenuation to lowest the following tissues: soft tissue, bone, lung, fat, muscle

Answer 23

bone, muscle, soft tissue, fat, lung

Question 24

compare the radiographic appearance (density) of positive contrast media with negative contrast agents.

Answer 24

positive contrast media (density) is bright

negative contrast agent ( density) is dark

Question 25

Provide examples of positive and negative contrast agents?

Answer 25

Positive agent = barium and iodine | negative agent = air and gas

Question 26

compare the recommended kVp ranges for GI procedures using barium only, barium with air and aqueous agents

Answer 26

barium 100-125kvp double contrast 90-100kvp aqueous 80-90kVp GI procedures 70-75 (analog) 75-80 (digital)

Question 27

Explain the effect of filtration on beam intensity and beam quality

Answer 27

beam intensity - decrease | beam quality - increase

Question 28

Define HVL. What does HVL measure

Answer 28

HVL determines the filtration to the tube is correct and beam should only decrease 1/2 of the value HVL measures the beam intensity after filtration has been added

Question 29

What is the difference between tube filtration and compensating filtration? Compare the purpose of each

Answer 29

tube filtration is what is in or on the tube to reduce low energy photons hitting the patient. compensating filtration is what is used to compensate for anatomical parts being photograph with different attenuation factors.(wedge and trough)

Question 30

What are the 2 purposes of collimation

Answer 30

1. reduce patient exposure | 2. reducing the amount of scatter radiation produced within the patient

Question 31

List 4 types of collimation devices

Answer 31

cones, cylinder, apertures and collimator boxes

Question 32

what is the relationship on increased collimation on field size and volume of tissue exposed?

Answer 32

increased collimation = small field size and less tissue being exposed on the patient

Question 33

what is the effect of increased collimation on the following image qualities?

Answer 33

scatter noise=decrease contrast=increase film density=decrease detail sharpness=no effect

Question 34

explain mAs reciprocity

Answer 34

verifies the insistency of radiation intensity for changes in ma and exposure time

Question 35

What does linearity state about the relationship between radiation exposure and mA, s, and mAs?

Answer 35

that mA time S = mAs

Question 36

what is the name of the device that is used to measure x-ray intensity?

Answer 36

dosimeter or film badge

Question 37

what is the unit of measurement for x-ray intensity?

Answer 37

roentgen

Question 38

collimator misalignment should be ____ ______ ___ of the SID used

Answer 38

less than 2\

Question 39

how much ( in inches) can the collimator be misaligned if using 40" SID

Answer 39

0.8"

Question 40

PBL does not allow technologist to collimate to a field size that is larger that the IR (true/false)

Answer 40

true

Question 41

PBL was once required by federal law but currently is not (true/false)

Answer 41

true

Question 42

Excessively bright or dark digital images are produced by rescaling errors (true/false)

Answer 42

true

Question 43

if there is rescaling errors, the exposure index is not accurate (true/false)

Answer 43

true

Question 44

if collimation guidelines are not followed an excessively bright or dark image may be produced when using a digital IR (true/false)

Answer 44

true

Question 45

explain the difference between off-focal radiation and scatter radiation

Answer 45

off focus radiation come from electrons that strike somewhere other then anode, and scatter radiation come form the patients anatomical parts

Question 46

why is it desirable to reduce off-focal radiation and how can it be reduced?

Answer 46

it contributes to patient dose | it can be reduced by double aperture device, extension cylinder or collimator box.

Question 47

Summarize the guidelines for collimation and split exposures when using a CR image receptor. Why is important to follow these guidelines?

Answer 47

``` 2 exposure fields should be used except for digits shield all areas not being exposed symmetry is important no overlap between field collimation margins between fields ```

Question 48

To utilize the anode heel effect, the cathode end of the tube should be positioned over the thickest body part of interest (true/false)

Answer 48

true

Question 49

the total required filtration reduces patient skin dose without any effect on radiographic images (true/false)

Answer 49

true

Question 50

high kv should be used with body parts that have high subject contrast (true/false)

Answer 50

true

Question 51

increasing added filtration to the tube will decrease the HVL (true/false)

Answer 51

false

Question 52

as collimation in increased (select all that apply)

Answer 52

size field decrease contrast increase film density decrease scatter radiation decrease

Question 53

what are the effects of scatter radiation on image quality

Answer 53

film density increase contrast decrease scatter noise increase

Question 54

a sthenic patient will attenuate more of the x-ray beam than a hyper sthenic patient of the same size and thickness (true/false)

Answer 54

true

Question 55

when using a wedge filter for a AP foot the thinnest end of the filter should be paced over the toes (true/false)

Answer 55

false

Question 56

which of the following conditions will make the anode heel effect more notice

Answer 56

longer IR small focal spot shorter SOD

Question 57

positive contrast agents increase attenuation because of the high physical density (true/false)

Answer 57

false (atomic #)