SG2 Flashcards by Naomi Ngo

what is one misconception about digital radiography

digital produce lower dose

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what factors remain the same for both digital and film radiography

xray imaging system
xray production
xray emission

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What is the expectation of digital radiography

low dose

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what are the differences bw film and digital

minimal retakes
consistent image quality
radiation exposure reduced by 20-50% w/o loss of image quality
radiographs can be processed after acquisition

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which of the following is a benefit of digital radiographs to produce consistent image quality?
a. narrow exposure latitude
b. wide exposure latitude

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the expectation of lowering patient dose will ___
a. increase the need to increase technical factors
b. increase the need to repeat
c. decrease the need to repeat

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why is there an expectation of lowering pt dose to decrease the need to repeat

poor technique

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overexpose patient is due to ___

repeat

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digital radiography reduce motivation towards ___ (4)

appropriate technique
patient shielding
proper collimation
correct positioning

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how much exposure cannot be recognized as too black
a. eigth fold
b. twenty fold
c. ten fold
d. five fold

ten fold exposuure

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67% of ____ has no shielding
a. pelvic
b. thyroid
c. abdomen
d. urinary bladder

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___% shield is correctly placed?
a. 10
b. 20
c. 50
d. 80

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82.3% of repeats are due to ___
a. lack of shielding
b. positioning errors
c. inappropriate technique

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what are the variables involves in the production of diagnostic images? (3)

anatomy
positioning
physics, principles of exposure

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what is the radiographer’s responsibility before the image is sent to the radiologist

image analysis

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what is used to critically think through the problem and resolve the situation

problem-solving process

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what are the steps to analytical process

recall purpose of exam
check for good balance bw visibility of detail and geometry of image

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A good radiograph will have a balance between visibility of ___ & ___

detail
geometry of image

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what are the 3 steps to effective image critique method

classify image
determine cause of problem
recommend corrective actions

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what are the 4 critiques to classification of images

1.within diagnostic limits?
2. optimal quality?
3. diagnosis –> continued critique
4. repeat –> MANDATORY continued critique

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which of the following is mandatory for continued critique before attempting to repeat
a. if the image is submitted for diagnosis
b. if the image needs a repeat

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what are the 3 reasons to determine the cause of unacceptable/suboptimal image?

technical
procedural factor
equipment malfunction

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which of the following is not procedural factor?
a. proper positioning of body part
b. proper removal of radiopaque object
c. proper record history & communication
d. maintain IR exposure

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which of the following related to visibility of details?
a. resolution
b. sharpness
c. focal spot size
d. kVp/mAs

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A problem that involves patient positioning or patient preparation for the exam is __ a. technical problems b. procedural problems c. equipment malfunction

Proper patient positioning is when ___ (3) aligned with one another

part IR CR

Proper patient preparation is ___ (3)

1. remove the radiopaque object 2. proper bowel cleansing 3. record a thorough history and communication

Which problem can be kept to a minimum through an effective quality control program? a. technical problem b. procedural problem c. equipment malfunction problem

Problems with density/IR exposure related to ___ a. kvp b. mAs c. size d. IR

Problems with contrast related to ____ a. kvp b. mAs c. size d. IR

Problems with recorded detail related to ___ a. kVp b. mAs c. IR d. size

Problems with distortion related to ___ a. kvp b. mAs c. size d. IR

what are the demographic info of an optimal image?

1. pt & facility name 2. time & date 3. CR-cassette & pt barcode scanned 4. DR exams match w pt info

what do you do if demographic info is incorrect?

fix everything before send to PACS

What is the appropriate range of collimation required of the surrounding anatomy? a. 1-2" b. 0.5-1" c. 0.05- 0.5" d. 0.8-1.3"

What does good collimation result in

1. proper anatomy showed 2. decreases patient dose 3. improve visibility of recorded detail 4. reduce histogram analysis errors

Good collimation improves ____ a. sharpness b. spatial resolution c. contrast d. patient dose

what happened if IE # indicates that the IR received less than needed exposure to put in range a. underexposed b. overexposed

what happened if EI# receive more exposure? a. underexposed b. overexposed

quantum noise related to _____ a. underexposed b. overexposed

Saturation related to ____ a. underexposed b. overexposed

excessive scatter related to _____ a. underexposed b. overexposed

When is underexposed projection not repeated? a. loss of contrast b. increase in saturation c. presence of quantum noise d. additive condition

when is overexposed projection is not repeated? a. presence of quantum noise b. excessive scatter c. loss of contrast d. destructive condition

when is underexposed projection is repeated? (3)

1. IR receive less than needed exposure 2. loss of contrast 3. quantum noise that cannot be fixed by postprocessing

when is overexposed projection is repeated?

1. IR receive more exposure 2. loss of contrast 3. saturation occur 4. excessive scatter

Increase in kVp results in ____ projection a. underexposed b. overexposed

Decrease in mAs results in ____ projection: a. underexposed b. overexposed

an underexposed projection will be caused by____ kvp & ____ mAs a. increase, increase b. decrease, decrease c. increase, decrease d. decrease, increase

An overexposed projection will be caused by ____ kvp & ____ mAs a. increase, increase b. decrease, decrease c. increase, decrease d. decrease, increase

if backup timer of AEC was shorter than exposure time, it will cause ___ a. underexposed b. overexposed

If wrong chamber of AEC is activated, it will cause ___ a. underexposed b. overexposed

A non-grid technique with a grid will cause ____ a. underexposed b. overexposed

a grid technique without a grid will cause ____ a. underexposed b. overexposed

an underexposed projection occurs due to ___ a. increase in kVp b. use grid technique without a grid c. grid is off level or cut-off d. increase mAs

which of the following causes of underexposure do not need a repeat? a. increase SID w/o decrease mAs b. increase SID w/o increase mAs c. destructive condition d. small field size is used

which of the following causes of overexposure do not need a repeat? a. increase SID w/o decrease mAs b. increase SID w/o increase mAs c. destructive condition d. small field size is used

A & C

if patient has additive condition, it causes ____ a. underexposed b. overexposed

if patient has destructive condition, it causes ___ a. underexposed b. overexposed

CAUSES OF OVEREXPOSURE, BUT DON’T REQUIRE A REPEAT is when ___ (2)

1. increase SID w/o decrease mAs 2. pt has destructive condition

CAUSES OF UNDEREXPOSURE , BUT DON’T REQUIRE A REPEAT is when ___ (3)

1. increase SID w/o increase in mAs 2. Large field size was used w/o increase in mAs 3. patient had an additive condition

what are the technical considerations for imaging obese patient (3)

1. increase attenuation 2. increase mAs & kVp 2. greater SNR

For every ___cm of added tissue thickness, the mAs should be doubled

4cm

doubled mAs to maintain IR exposure will demonstrate ____ a. low contrast b. high contrast c. high resolution d. low resolution

For every cm of added tissue thickness, the kVp should be increased by ____

which of the following will increase scatter and decrease contrast a. doubled mAs b. increased kVp by 2

____ should be set as high as possible to reduce dose but not so high that it creates scatter a. mAs b. kVp c. mA d. seconds

what will be increased if kVp is increased by 2? a. scatter b. contrast c. resolution d. dose

A & D

what will be decreased if kVP is increased by 2? a. scatter b. contrast c. resolution d. dose

if kVP increased by 2, ___? (3)

1. increase dose 2. increase scatter 3. decrease contrast

technical adjustments for S-M plaster cast? a. +5-7Kvp, 50%-60% mAs b. +8-10kVp, 100% mAs c. no adjustment

technical adjustments for L plaster cast? a. +5-7Kvp, 50%-60% mAs b. +8-10kVp, 100% mAs c. no adjustment

technical adjustments for fiberglass cast? a. +5-7Kvp, 50%-60% mAs b. +8-10kVp, 100% mAs c. no adjustment

To demonstrate long bones with the least amount of distortion, the CR should be _____ & IR should be ____ a. perpendicular, parallel with bones long axis b.. parallel, perpendicular to bones long axis

the relationship bw CR, IR and bone will determine ____

degree and type of distortion

What is the Law of Isometry

the CR should be set at ½ of the angle formed between the object and IR to minimize foreshortening

A ___ CR best demonstrates the anatomic relationships at the joints a. parallel b. perpendicular

What are the main 4 components of CT unit

1. gantry 2. xray tubes 3. table 4. collimator

which component of CT unit is a movable frame and the most visibile part? a. gantry b. xray tubes c. table d. collimator

Which component of CT unit produce excessive heat? a. gantry b. xray tubes c. table d. collimator

Which component of CT unit determine the voxel length or section thickness? a. gantry b. xray tubes c. table d. collimator

which component of CT unit decrease beam attenuation? a. gantry b. xray tubes c. table d. collimator

xray tubes can produce _____ exposure per examinations? a. 30 b. 20 c. 40 d. 50

Accurate centering will avoid ___

degrade edge image

what does Gantry include?

Xray tubes & detectors

what material is made of the table of CT unit

carbon graphite fiber

carbon graphite fiber can ____ beam attenuation

decrease

collimators of CT unit varies from ____ a. 1-5mm b. 1-10mm c. 1-13mm d. 1-15mm

what controlled the collimators of CT unit?

software program

collimation width determines _____ or ___

voxel length or section thickness

what does doubled collimated mean?

radiation beam - tube exit detector entrance

what is the aperture for Gantry of CT unit? a. 10-20" b. 30-40" c. 20-34" d. 25-35"

What does detectors of CT respond to

extreme speed without lag

what is CT detector high capture efficiency a. how well detectors receive photon from patients b. how well detectors receive photons from xray tube c. how well detectors convert incoming xray photons d. how well detectors converts absorbed photon info to digital signal for computer

what is CT detector high absorption efficiency a. how well detectors receive photon from patients b. how well detectors receive photons from xray tube c. how well detectors convert incoming xray photons d. how well detectors converts absorbed photon info to digital signal for computer

what is CT detector high conversion efficiency a. how well detectors receive photon from patients b. how well detectors receive photons from xray tube c. how well detectors convert incoming xray photons d. how well detectors converts absorbed photon info to digital signal for computer

CT detectors receive photons from ____ a. xray tube b. collimator c. patient

which of the following control CT detector high capture efficiency? a. distance bw detector b. thickness of detector c. material used for detector d. size of detector

A & D

which of the following control CT detector high absorption efficiency? a. distance bw detector b. thickness of detector c. material used for detector d. size of detector

B, C , D

how to increase the sensitivity of the solid state detector

allow incoming xray beam to be a diverging fan shape

which of the following cause concentric ring artifact? a. tight collimation b. wide collimation c. misalignment

which of the following cause star pattern artifact? a. misalignment b. object of greatly different contrast c. tight collimation

CT image quality is controlled by _____

resolution & noise

Resolution depends on ____ (3)

pixel, voxel, matrix size

Noise on CT image related to amount of data collected by ___

detectors

Most noise is a result of ____

statistical fluctuation in the info recorded by detectors

___ is used in fluoroscopy to reduce patient dose and should be used whenever possible

pulse progressive fluoroscopy

Table top exposure rate should not exceed ___ a. 5R/min b. 7R/min c. 10R/min d. 12R/min

which audible timer is served as a reminder of how much time has been used in fluoro? a. 4min b. 5min c.7min d. 8min

which part of fluoro cause increased in patient dose?

magnification image intensifier

magnification image intensifier caused an increased in ____ a. dose b. contrast. c. resolution

Lead apron and gloves must be at least _____ a. 0.2mm Pb/eq b. 0.5mm Pb/eq c. 0.15mm Pb/eq d. 0.05mm Pb/eq

the highest source of exposure is _____

scatter from patient

A ____ mm Pb/eq lead shield should cover bucky tray a. 0.2mm Pb/eq b. 0.5mm Pb/eq c. 0.25mm Pb/eq d. 0.05mm Pb/eq

what is photoemission

emit e- when illuminated by input phosphor (electron emission after light stimulation)

the # of e- emitted = ____

light intensity

increased in strength of e- emitted = ___ light

increase

less intense light is ___ wavelength ___ frequency

long short

photoemission happened at____ a. anode b. cathode

what is the material for input phosphors? a. cesium iodine b. zinc cadmium sulfide c. Cs d. Aluminum

what is the material for output phosphors? a. cesium iodine b. zinc cadmium sulfide c. Cs d. Aluminum

input phosphors located at ___ a. anode b. cathode

output phosphors located at ___ a. anode b. cathode

_____ bond to input phosphors

photocathode

convert energy into visible light is____ a. input phosphors b. output phosphors

convert electrons into light is____ a. input phosphors b. output phosphors

____ is the site where accelerated electrons interact and produce light a. anode b. cathode

Photoelectron at output phosphor produces ____ more light photons a. 50-75 times b. 40-50 times c. 60-70 times

what is last image hold

maintain last image until it is replaced

what is pulse fluoro

high-power generator that is combined with a detector comprised of a TFT in contact with image intensifier output anode screen

what are the post processing advantages of digital fluoro (3)

window level and width filtering techniques digital substraction

Xray generator must switch on and off to accommodate for ____ (2)

interrogation time extinction time

time required to turn on generator is ___ a. interrogation time b. extinction time

time required to turn off generator is ___ a. interrogation time b. extinction time

interrogation time ___ a. achieve necessary kVp & mAs b. prepare for next pulse

extinction time ___ a. achieve necessary kVp & mAs b. prepare for next pulse

how last image hold reduce patient dose

a single frame image is displayed continuously until next exposure is required

how pulse fluoro reduce patient dose

short burst of radiation produce individual frames

function of magnification tube

magnify image electronically by changing voltage on electrostatic lens

increase voltage = ___ focus e- at closer to input screen

increase

image is magnified when reach ____ screen

output

function of photocathode

emit e- when stimulated by input phosphor

electrons accelerate from ____ to ___ and ___

cathode anode output screen

primary brightness gain occurs from _____ (2)

acceleration focusing of electron beam

function of output screen

converts electrons into light which are available for viewing

the ratio of the number of light photons at the output phoshor to the number of xrays at the input phosphor is ___ a. brightness gain b. flux gain c. magnification gain

The ratio of the square of the diameter of the input phosphor to the square of the diameter of the output phosphor is____ a. brightness gain b. flux gain c. minification gain

The product of the minification gain and the flux gain is ___ a. brightness gain b. flux gain c. minification gain

flux gain equation

output light photons/ input xray photons

[flux gain] - number of input xray photons should be ____ than output light photons

less

minification gain happened due to ___

the same number of electrons that were produced at the LARGE input screen being compressed into the area of the SMALL output screen

output phosphor is ____ a. 2.5-5cm b. 10-40cm

input phosphor is ___ a. 2.5-5cm b. 10-40cm

minification gain equation

(di/do)^2

minification gain is an increase in ____ a. brightness/ intensity b. density c. # of photons d. quality

brightness gain of image intensifiers ____ with tube age and use

decrease

fluoro xray tubes are designed for ___ operation times at ___ mA a. shorter, higher b. longer, lower

tube target of fluoro xray tube is set to _____

prevent SOD of less than 15"

diameter of output phosphor is ___ a. 2.5-5cm b. 10-40cm

diameter of input phosphor is ___ a. 2.5-5cm b. 10-40cm

inverse square law formula

I1/I2 = (d2)^2/ (d1)^2

15% rule

decrease kVp by 15% and double mAs

which radiation-induced response is directly related to dose? a. deterministic b. probabilistic

which radiation-induced response is proportional to dose? a. deterministic b. probabilistic

SSD for mobile radiography a. > 12" b. < 12" c. > 15" d. < 15"

what are 2 goals for Radiation protecion

1. prevent occurrence of serious radiation-induced 2. reduce stochastic effects to acceptable degree

effective dose limit for occupational worker a. 50 mSv/y b. 50 mSv/ mo c. 30 mSv/y d.30 mSv/ mon

Which of the following is a specialized procedure that produces a series of 3-D images to better visualize abnormal tissue superimposed by normal tissue? a. Digital Subtraction b. Panorex c. Mini C-Arm d. Digital Breast Tomosynthesis

During linear tomography, the amount of blur created in the image is directly related to the: a. Tomographic Angle b. Object Plane c. Pivot point d. Length of exposure time

A typical effective dose of a barium enema is approximately 8 mSv. Using the BERT method this could be compared to ________________ of natural background radiation. a. 1.0 year b. 2.4 days c. 2.7 years d. 182 days

During portable radiographic exams the SSD should never be less than: a. 56 inches b. 24 inches c. 12 inches d. 40 inches

The effective dose limit for the lens of the eye for occupationally exposed individuals is: a. 5 Sv b. 500 mSv c. 150 mSv d. 50 mSv

The effective dose limit for skin, hand, feet for occupationally exposed individuals is: a. 5 Sv b. 500 mSv c. 150 mSv d. 50 mSv

which of the following creates images of an anatomic area within a plane while blurring structures above and below a. DXA b. C-arm FLuoro c. Linear TOmography d. Panorex

when performing mobile imaging, the minimum distance a radiographer should stand away from primary beam is ___ a. 2 feet b. 2m c. 10 feet d. 10m

BERT stands for___ a. beneficial exposure radiation time b. barium enema radiation tomography c. background equivalent radiation time d. below equivalent reduction time

What is an advantage of C-arm fluoroscopy compared with traditional image-intensified fluoroscopy in a standard x-ray room? a. the x-ray tube can be positioned under the patient b. provides dynamic imaging c. monitors total fluoroscopy time d. allows imaging in a variety of planes

In mammography, because the breast has _____ subject contrast, it is necessary to use a _____ kilovoltage exposure technique. a. high, high b. low, high c. high, low d. low, low

During DXA scanning, the T-score indicates the number of standard deviations the individual measurement is from the data mean for a population sample of _____. a. similarly aged individuals b. a wide range of age groups c. young, healthy adults d. older, healthy adults

During linear tomography, a smaller tomographic angle will create: a. increased amount of blur. b. decreased focal plane thickness. c. increased focal plane thickness.

The circular structure that the patient and table travel through during the CT scanning process that encompasses the x-ray unit, data acquisition system, and the detector/detectors is the: a. donut. b. couch. c. magnet. d. gantry

In a major improvement from single-slice CT acquisition, spiral (helical) CT allowed: a. continuous movement of the table and the patient through the gantry. b. the entire volume of tissue to be scanned in one acquisition. c. scan time to be reduced. d. all of the above.

The ____ controls how much of the detector is exposed during CT imaging, and severely limits the amount of scatter reaching the detectors. a. prepatient collimator b. postpatient collimator c. bowtie filter d. detector array

The amount of CT numbers that are visible in the image is known as the: a. window level (WL). b. window width (WW). c. raw data. d. histogram

The ability of the image to differentiate between structures with very different attenuation characteristics (CT numbers) when they are very close together is known as the: a. patient dose. b. contrast resolution. c. edge enhancement filter. d. spatial resolution.

The ability to discriminate between structures with very similar attenuation characteristics (CT numbers) is known as the: a. patient dose. b. contrast resolution. c. edge enhancement filter. d. spatial resolution.

Which of the following statements is true regarding the use of lead shielding during CT? 1. The AAPM recommends against using lead shielding in lieu of other methods of radiation protection. 2. Lead shielding of radiosensitive tissues can be effective in limiting radiation dose when the shields are placed appropriately outside the SFOV (out-of-plane). 3. The lead shielding must completely surround the patient, because the tube(s) travel in a circular motion. 4. The lead shielding must lie on the couch, because the radiation comes from the area around the table. a. 1 only b. 2 and 3 only c. 2 and 4 only d. All of the above