RADT 1075 Final

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The optical density range visible to the human eye is

0.25 to 2.50

How many bytes are needed to store one alphanumeric character?

1

If a particular radiographic exposure requires 50 mAs and the 400 mA station is selected, what exposure time is required?

1/8 second

A perfect image processing system would have an MTF of:

100%

The magnification factor for a radiographic procedure is calculated as 1.25. It may be assumed that there is a ____ magnification of the object size.

125%

Which rule is used as a guide to maintain the same density when kVp changes?

15% rule

increasing kVp from 85 to 98 kVp

15% rule

The first version of DICOM was completed in:

1985

The minimum change necessary to cause a visible shift in density is ___% of mAs.

25-35

After completing a radiograph using 27 mAs at 90 kVp, the image demonstrates adequate overall density but an area that is under penetrated. In order to produce an optimum image in terms of contrast and penetration, the repeat image should be taken at

27 mAs and 100 kVp

A chest radiograph is produces with sufficient optical receptor exposure using 10 mAs at 72 inches. If the same radiograph is performed at 44 inches SID, what new mAs should be used to produce the radiograph with the same receptor exposure?

3.7 mAs

The k-edge of phosphor imaging plates ranges from _____ keV.

30 to 50

How many bits make up four bytes?

32

In order to achieve a true SID of 40" with an x-ray tube angle of 30 degrees, the overhead scale should read

34.6 inches

Depending upon kVp range, a visible change in contrast will not be seen unless kVp is minimally changed

4-12%

The range of kVp that can be used with PSP systems is:

40 to 120

If a PC had a 5.0-GHz CPU, it would have a system clock that would tick _______ billion times per second.

5

The grid conversion factor for a 12:1 grid is:

5

The wavelength of the PSP reader laser is ________ nm.

633

A pixel bit depth of 2 to the 16th power will demonstrate _________ shades of gray.

65,536

A server is:

A computer that manages resources for other computers.

Which of the following describes a thick-client computer?

A computer that works independently of the network.

Which examination does not exhibit an inherently large OID?

AP lumbar spine

When the imaging plate is irradiated, stimulated electrons enter the _______ layer.

Active

Which of the following describes a thin-client computer?

Any computer that needs a server for task completion

Which statement is FALSE?

As mAs decreases, exposure increases.

All of the following use buses that are found within the computer except the:

BCBV

The series of connections, controllers, and chips that create the information highway within the computer system is known as the:

BUS

UNIX was developed by:

Bell

A device that acts like a camera in an indirect conversion detector is known as a:

CCD

A detector in which each pixel has its own amplifier is known as a:

CMOS

Which of the following flat-panel detector technologies was developed by NASA?

CMOS

X-ray tube angulations inherently

Change the SID and introduce magnification to some degree.

kVp controls the proportional relationship

Compton and photoelectric interactions

H & D curve

D log E

If you increase beam restriction/collimation, what happens to density/receptor exposure?

Decreases

_________ represents how close the dots are located to one another within a pixel.

Dot pitch

(T/F) Automatic rescaling can be substituted for appropriate technical factors.

False

(T/F) Historical study patient examinations can be accomplished through the manual send function.

False

(T/F) Image aliasing is similar to the moire effect caused by grid error.

False

(T/F) It is possible to achieve an MTF of 100%.

False

(T/F) MTF is a way to quantify the contribution of each system component and the component's overall efficiency.

False

(T/F) No matter where the orientation stickers or labels exist on a digital cassette, the image will display correctly.

False

(T/F) Shuttering removes the dark exposed border, reducing the amount of information to be stored.

False

Which of the following has NO impact on radiographic contrast?

Focal Spot size

Which of the following has NO impact on radiation exposure to the patient?

Focal spot size

Which of the following require more critical beam centering?

Focused grids

The number of grid lines per centimeter or lines per inch describes grid:

Frequency

What metal is contained behind the outer layers of a DVD?

Gold

The air gap technique can be used as an alternative to:

Grids

The system that contains patient information, billing records and inpatient orders is the:

HIS

Which statement best describes a charge-coupled device?

It is the oldest indirect conversion technology used in a variety of image capture applications.

The least expensive network to install is a:

LAN

measures accuracy of image compared to original object

MTF

As the spatial frequency of objects increases,

MTF decreases

the quotient of SID over SOD

Magnification Factor

Resolution is improved when

OID decreases

Large patients receive a greater exposure than small patients because their

OID is increased, SOD is decreased, entrance skin surface is closer to the source.

"Write once, read many" is represented by which of the following identifiers?

R

The fastest and most versatile port is the:

SCSI

Devices commonly referred to as roles include:

SCU

All of the following affect visibility of detail EXCEPT

SID

Resolution is improved when

SID increases

Penumbra decreases as

SID increases, OID decreases, and focal spot size decreases

Size distortion is controlled by

SID, OID, and radiographic distances.

Magnification Factor

SID/SOD

SID/Magnification Factor

SOD

The most popular base material used in integrated circuits is:

Silicon

Image receptor contrast is expressed as the ______ of the D log E curve.

Slope

Proper patient demographic input is the responsibility of the:

Technologist

Which of the following statements about scintillators is true?

The amount of x-rays absorbed depends on the type of scintillator.

A device that includes a photosensitive array and small pixels that convert light into electrical charges is known as a ________ transistor.

Thin-film

(T/F) Air kerma is the measurement of radiation energy absorbed in a unit of air.

True

(T/F) Basic workstation functions include contrast manipulation, edge enhancement, and smoothing.

True

(T/F) The shape of the histogram is anatomy specific.

True

A technologist can lend credibility to his or her expertise by:

Using personal position markers.

The anode heel effect is more pronounced with

a 10 degree target angle

Which radiograph exhibits the best detail?

a PA chest radiograph for evaluation of the heart at 72 in.

In general radiography, quantum noise is

a function of mAs and kVp.

The brightness of the image on a viewing monitor is

a function of the monitor

Which generator produces the greatest amount of radiographic density per mAs?

a high-frequency generator

Raw data used to form the image histogram are compared with:

a normal histogram of the anatomic part

Photoconductors are materials that:

absorb x-rays and produce electrical charges.

The layer of the imaging plate that traps electrons during exposure is the ________ layer.

active

inadequate sampling of incoming data on a monitor

aliasing

If the entire range of exposure were digitized, pixel values representing ______ would be digitized.

all values

The type of flat-panel detector that uses thin films of silicon integrated with arrays of photodiodes is known as a(n):

amorphous silicon detector

Quantum efficiency is a measurement of the:

amount of electrons produced relative to the incident light from the scintillator.

When digital imaging receptors are used,

an exposure at 90 kVp would require a grid.

The exposure indicator number is:

an indication of radiation absorbed by the imaging plate.

The workstation function that allows selection of preset terms or manual text input is termed image:

annotation

variation in beam intensity along the long axis of beam

anode heel effect

In an effort to display the pixels for the area of interest when exposure is greater or less than what is needed to produce an image, _______ occurs.

automatic rescaling

A change in kVp, as an exposure factor, affects

average beam energy, the amount of scatter production, and beam intensity

The phosphor layer is made of phosphors from the ______ family.

barium fluorohalide

When insufficient light is produced by the imaging plate phosphor, the image will:

be grainy

A severely underexposed image will

be unable to visualize recorded detail

The total amount of irradiated material is a function of

body part thickness and area of exposure

During laser beam formation, both ends of the laser reflect energy back and forth so that the atoms:

bombard each other

When evaluating the degree of resolution on an actual radiographic image, an effective tissue to analyze is

bony trabecular pattern.

How dark or light a digital image appears on a display monitor is known as:

brightness

Image level parameters control image:

brightness

A renal calculus that measures 0.2 mm in size

cannot be visualized with an effective focal spot of 0.5 mm focal spot due to penumbral overlap.

Which of the following statements is not true?

changing the matrix and the FOV will not change the size of the pixel

Detector elements are formed by voltage gates that _______ at readout to _______ the flow of electrons.

close; allow

In the binary code, the value of one is assigned when a transistor is ________ and the current _________ through.

closed;passes

Cable consisting of a center conducting wire surrounded by insulation and a grounded shield of braided wire is called:

coaxial

The imaging plate layer that absorbs stimulating light and reflects emitted light is the ______ layer.

color

Two or more objects sharing resources and information or computers, terminals, and servers interconnected by communication channels is a definition of a:

computer network, wide area network (WAN), local area network (LAN).

Changing the slope of the look-up table graph will increase or decrease:

contrast

Detector performance is measured with all of the following except:

contrast

Window width controls the ratio of black and white, also known as:

contrast

The 15% rule changes

contrast and density

The ability of a digital system to display subtle changes in shades of gray is called:

contrast resolution

Changing the steepness of the exposure gradient:

controls image contrast

Using an FOV that is much larger than the part being examined will:

decrease resolution

If you decrease kVp, what happens to density/receptor exposure?

decreases

Collimation to a smaller area:

decreases compton interactions

The improper algorithm application may result in:

degradation of the imaging.

direct relationship between mAs and distance

density maintenance formula

The number of bits per pixel is known as bit:

depth

The efficiency of a system to convert x-ray input signal into a useful output image is known as:

detective quantum efficiency

Multiple numeric values divided into an array of small elements capable of being processed is the definition of ______ images.

digital

The effect of mAs upon IR exposure is

directly proportional

The optical mirror in the reader:

directs the laser beam to the imaging plate surface.

A system's ability to respond to varying levels of exposure, resulting in more detail, is referred to as:

dynamic range

The concept of contrast as it is displayed on a soft-copy monitor for digital images is described as

dynamic range

Amplification of the frequencies of the areas of interest is known as:

edge enhancement

The system that holds a specific patient's lab results, radiology reports, and physician's notes is the:

electronic medical record (EMR)

Which of the following occurs when the tube or image receptor is not properly aligned?

elongation

Contrast decreases with

excessive density, inadequate density, a wider range of densities.

Which of the following statements is not true?

exposure index refers to the amount of exposure to the patient

Which one of the following serves to protect against static build-up, dust collection, and mechanical damage to the imaging plate?

felt material

The most fragile type of network connection is:

fiber optic

The network connection that uses glass threads to transmit data is:

fiber optic

A device that acts like a switch to send electrical charges to the image processor in a direct conversion flat-panel detector is known as a _______ transistor

field-effect

The refresh rate controls the:

flicker

All of the following factors would affect radiographic contrast EXCEPT

focal spot selection

Factors affecting recorded detail include

focal spot size

Which of the following has NO impact on receptor exposure?

focal spot size

small and large

focal spot size

Which one of the following occurs when the part is improperly aligned?

foreshortening

The _____ the SID, the _____ the magnification.

greater;smaller

A radiograph that demonstrates considerable differences between densities is called

high contrast

A radiograph with few shades of gray exhibit

high contrast

When choosing between two radiographic grids, the k factor is different. Choosing a grid with the higher K factor will produce an image with

high contrast

fewer shades of gray across the final image

high contrast

Which generator type results in the GREATEST DECREASE IN CONTRAST?

high frequency

When the tissue structure of the ankle joint is considered, the dramatic tissue differences between the muscles and the bones of the ankle produce

high subject contrast

Data collected within the collimator are represented by a:

histogram

A GUI is best known as a(n):

icon

The selection of the incorrect body part from the examination menu may result in:

image misinterpretation

Grid use for PSP examinations is more critical than in film/screen radiography because CR:

imaging plates record more densities

Focal spot and OID affect image sharpness ______ imaging.

in both film/screen and digital

Slow film-screen combinations

increase resolution

Which of the following can be done to decrease the change of having image lag occur in the next image?

increase the amount of time between exposures.

If you increase density/receptor exposure, density is

increased

A radiograph that demonstrates considerable differences between densities is called

increased contrast, high contrast, short scale.

All of the following will increase radiographic film density EXCEPT

increased dryer temperature

Contrast increases with all of the following EXCEPT

increased scatter

As OID increases and SID remains constant, entrance skin exposure (ESE)

increases

As size distortion decreases, the resolution of recorded detail

increases

As the anatomical part size increases, the amount of scatter created by the part

increases

In digital imaging systems, increasing sampling frequency of the data.

increases image fidelity.

Most radiographers will use more exposure than required for a procedure. This does what to patient exposure?

increases patient exposure

As tissue density increases, the amount of scatter ______, which also results in a _________ in contrast.

increases, decreases

As the slope of the D log E curve _______, contrast _______.

increases, increases.

As kVp _____, a ______ range of photon energies is produced

increases, wider

As kVp increases, the percentage of Compton interactions _______ and contrast ______.

increases; Decreases

Which of the choices below DOES NOT increase contrast?

increasing the amount of irradiated tissue

Quantum mottle is caused by:

insufficient light

The density maintenance/direct maintenance formula mathematically resembles the

inverse square law

The relationship between exposure and SID is

inversely proportional to the square of the distance

Which can negatively impact recorded detail?

involuntary motion

Because of the "heel effect", x-ray beam intensity

is greater under the cathode side of the tube

Imaging noise is different from quantum noise in that imaging noise

is inherent in the imaging system

The principal controlling factor of contrast is

kVp

Which factor influences the average energy of photons reaching the IR?

kVp

controls the average energy of the x-ray beam

kVp

In order to reduce patient entrance skin exposure (ESE), higher kVp exposures are a consideration. It is important to remember that

kVp values that are too high produce more scatter and reduce contrast

Best seen with the patient supine

kidneys

Examinations of body parts with a large inherent OID warrant a ______ whenever possible.

large SID

Which of the following does not determine PSP resolution?

laser scan speed

The range of exposure values the image detector is able to produce is known as:

latitude

The image reader scans and reads the image from the:

leading edge of the imaging plate to the opposite end.

PSP imaging plates are erased by flooding the plate with:

light

The unit of resolution in film/screen imaging is

line pairs per millimeter

Proper patient demographic input ensures:

linking of all the patient's files

low contrast

long scale contrast

A radiograph that demonstrates minimal differences between densities is called

long scale, decreased contrast, low contrast.

The more manipulation of the image, the greater the:

loss of information

switching from 10:1 grid to 6:1 grid

loss of visibility of detail

A radiograph that demonstrates minimal differences between density shades is called

low contrast

many shades of gray across the final image

low contrast

Which type of radiograph provides the most information?

low contrast images

If too few pixels are sampled, the result will be:

low resolution

Averaging the frequency of each pixel with surrounding pixel values to remove high-frequency noise is called:

low-pass filtering

The more light spread, the _______ the MTF

lower

The principal controlling factor of radiographic image density is

mAs

Which factor influences the number of photons reaching the IF?

mAs

controls x-ray beam quantity

mAs

As you analyze your image, you come to the conclusion that it must have more exposure. As a general rule, you should increase

mAs by 2x

Size distortion in radiography can be ____ only.

magnification

The best method for controlling motion when the patient is unable to cooperate is to

maintain mAs, while decreasing time.

The ability to send images to local network stations can be accomplished using the:

manual send function

The size of the pixel is determined by the:

matrix

Spatial resolution in digital imaging is determined by the

matrix size, pixel size, and bit depth.

A histogram displays the useful signal by locating:

maximum signal only.

Failure of the reader to find the collimation edges of an image:

may cause the image to be too bright or too dark.

Because the x-ray beam is divergent,

minification is impossible

All of the following are common SCSI devices except the:

modem

Which measures the accuracy of an image compared to the original object on a scale of 0 to 1?

modulation transfer function

"The sum of the components in a recording system cannot be greater than the system as a whole" is a definition of:

modulation transfer function (MTF).

The longer an image is stored in the computed radiography (CR) cassette, the:

more energy is lost by the electrons.

What should you expect to occur with a decrease in kVp?

more photoelectric interactions

The higher the kilovoltage peak, the:

narrower the histogram

In a bus network:

no switches of hubs are necessary

Amplifiers perform all of the following functions except:

noise cancelling

If you change the focal spot from small to large, what happens to density/receptor exposure?

nothing happens

Milliampere-seconds (mAs) is selected for the:

number of electrons needed.

Ratio between image size and Magnification

object size

A dot triad is a grouping of:

one green dot; one blue dot; and one red dot

Binary code is a computer language based on:

ones and zeros

To effectively take advantage of the anode heel effect, where should the thicker part of the anatomy be placed?

over the cathode

In the event of making a single exposure that is critical to the exam success, most experienced technologists will

overexpose the IR slightly, provide enough exposure to permit viewing with a bright light or adequate histogram.

inherently magnified in AP projections

patella

The purpose of the barcode label is to match the image information with the:

patient identifier

The greatest factor in the production of scatter radiation is

patient thickness

Focal Spot Size X OID divided by SOD

penumbra

Poor resolution is caused by unacceptable levels of

penumbra.

Proper alignment is achieved when the central ray is ____ to the part and ______ to the image receptor.

perpendicular, perpendicular

Resolution with intensifying screens will increase as _______ increases.

phosphor concentration

Ethernet protocol performs at the _______ layer.

physical

Each square in a matrix is called a:

picture element

Intermittent extraneous line patterns are ______ artifacts.

plate reader

Performing a routine chest radiograph in the AP projection will

produce improved resolution in the thoracic spine.

Scintillators are phosphors that:

produce light when absorbing x-rays

only corrected by increasing mAs

quantum mottle

results from insufficient mAs

quantum noise

The difference between two adjacent densities is

radiographic contrast

require an increase in mAs as ratio increases

radiographic grids

RIS is specific to:

radiology

You have completed a chest radiograph on a 2-month-old infant using a restraining device at a 72" SID. Because of the design of the device, your OID is suboptimum. The image reveals good resolution of the bony anatomy but the pulmonary vasculature is blurred. The EI value is 2040. In an effort to improve the quality of the repeat image, the competent radiographer would

raise the mA and decrease the exposure time.

The laser scans the imaging plate in a ______ pattern.

raster.

An increase in x-ray beam filtration

reduces contrast, increases the number of compton interactions, increases the average photon energy.

Demagnification is:

reducing the phosphor output image to the size of the active area of the CCD

Grid ratio describes the:

relationship between the height of the lead strips to the interspace

Cracks in the imaging plate can be caused by:

removing and replacing the plate in the reader

When the position of the patient is reversed, the direction of the tube angle must be ___ to maintain the relationship

reversed

The overall general shape of human anatomical structures are

round or oval

Critical characteristics of a digital image include all of the following except:

sample resolution.

The Nyquist frequency is

sampling a minimum of twice per cycle

The Nyquist theorem states that the:

sampling frequency must be twice the input signal bandwidth.

A wraparound image or image aliasing occurs when:

sampling occurs less than twice per cycle

A network switch:

sends data only to data-directed devices.

A network that uses a central computer that sends the entire original resource to the client is known as a:

server-based network

A look-up table is not used as a reference to:

set appropriate kilovoltage peak and milliampere-seconds values.

A fluoroscopic examination that uses barium as a contrast material would typically produce images with

short scale contrast

high contrast

short scale contrast

RAM is:

short term for open programs

Input of annotation for identification of the patient's left or right side:

should be used in conjunction with the technologist's anatomy markers.

Lossy compression is used to:

shrink file size

An image manipulation process that fills in the background so that it is darkened is known as:

shuttering

Distortion is a misrepresentation of

size and shape

Which of the following should be considered when selecting the PSP cassette?

size and type

low-pass filtering is also known as:

smoothing

Defective pixels can result from all of the following except:

software programs

The amount of detail present in any image is known as ______ resolution.

spatial

The ability of an imaging system to demonstrate small details of an object is known as:

spatial resolution

The process of joining two or more images into one continuous image is known as image:

stitching

contributing factor to total image contrast

subject contrast

The recorded detail of a radiographic image is visible because of

sufficient density, sufficient contrast

An archive query retrieves images from the PACS based on any of the following except:

technologist anatomical number

All of the following are considered impurities except:

tellurium

When sampling frequency is less than the Nyquist value

the Moire effect can occur

Recorded detail is

the accuracy of the structural lines actually recorded in the radiographic image, the degree of geometric sharpness and definition

As a last resort, which human immobilizer is used to hold a patient in position?

the male relative

High contrast is directly related to

the number of photoelectric interactions

Opening up the intervertebral joints of the cervical spine would best be accomplished with

the patient in an AP projection with a 40" SID

For general radiography, an MTF value of 1 is

theoretically impossible

In CsI detectors:

there is very little light spread

CsI detectors use:

thin crystalline needles

Kilovoltage peak (kVp) should be chosen:

to provide penetration

If all of the shades were left in an image after processing, the contrast would be:

too low

Coherent light is formed by the laser because the photons:

travel in the same direction

As focal spot size decreases,

umbra is improved, resolution increases, and penumbra increases

Possible causes of image lag include all but:

underexposure.

Automatic rescaling means that images are produced, regardless of the amount of exposure, with:

uniform contrast and density.

The system clock uses a:

vibrating quartz crystal

affected by photographic properties of image

visibility of detail

A digital detector with a high fill factor

will produce high resolution

Image brightness on an image display monitor is controlled by

window level

Flat-panel detectors that use indirect conversion technology convert:

x-rays to visible light

The ____ represents a depth to the information in the digital image

z axis

Magnification of the entire image at the workstation is termed:

zoom


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