IPE 2 Final Review

All of the following are considered advantages of digital imaging except?

Digital imaging has a narrow exposure latitude

Quantization is:

The process of assigning numerical data to the signal

A string of 8 bits is called aa:

Byte

A matrix with a greater number of pixels displays:

Greater spatial resolution

The number of shades of gray a system can digitize is called a:

Bit depth

A 16-bit depth system can display more shades of gray than a 4-bit depth system.

True

What is the measure of spatial resolution?

line pairs per mm

Which of the following describes the pixel pitch?

Measured from the center of one pixel to the center of the adjacent pixel and includes gaps between them

The ability of a material to respond to excitation and give off light is called:

scintillation

Which of the following describes conversion efficiency?

The percentage of energy absorbed by the receptor that is converted to usable output

Which of the following decreases the exposure required to produce an image, which decreases patient dose?

High DQE

Higher fill factor of a DEL equals:

Higher spatial resolution

Information patterns that don't add to the diagnostic image are called:

Noise

Higher ___ indicates that the receptor is more efficient in converting the input signal.

DQE

A picture element is also called a:

Pixel

The ability to distinguish small objects in a radiographic image is termed:

Spatial resolution

Pixel density and matrix size are fixed characteristics of a digital image receptor and cannot be altered by the technologist.

True

Absorption efficiency multiplied by conversion efficiency equals:

DQE

The element(s) used in flat-panel detectors as a scintillation material is:

Cesium iodide or Gadolinium oxysulfide

What term refers to the receptors' ability to respond to different exposure levels?

Dynamic Range

What term refers to the range of underexposure or overexposure that can occur and still produce an acceptable image?

Exposure latitude

A digital receptor can produce an image that appears acceptable but which was produced at ___% underexposure to ___% overexposure?

50, 100

After the image receptor collects the attenuated beam, the captured image is called:

Latent image

The process of converting the analog signal to a digital signal that happens in the ADC consists of which two steps?

Sampling and quantization

A series of boxes laid out in rows and columns that gives form to the image is called:

Matrix

Which of these statements is true regarding pixel size?

The smaller the pixel, the greater the spatial resolution

The number of pixels in a given area is called:

Pixel density

The type of flat-panel detector that converts energy from the X-ray beam directly into electrons is called?

Direct

In direct DR imaging, which of these materials converts light photons into electrons that migrate to thin-film-transistors (TFTs) and produce an electrical signal?

Amorphous silicon

In direct DR imaging, which of these materials is used to convert X-ray photons into electrons, which are collected by a TFT and produce an electronic signal?

Amorphous selenium

Which of these devices collects electrons emitted from either the amorphous silicon or amorphous selenium?

TFT

Which of these statements are true?

The lower the fill factor, the lower the spatial resolution

When purchasing X-ray equipment, which two of these should be considered by the department manager?

1. Dynamic range of the system

2. SNR of the system

Which of the following will produce an image with the highest resolution?

Narrow pixel pitch

Quantum noise limits the ability to see:

detail

What element traps and stores electrons that make up the latent image in F-centers?

europium activators

Which of these converts the analog signal to a digital signal?

ADC

Which of these is a graphic representation of the exposure values from the IR?

histogram

Which of these is described as a vertical line on the histogram that represents the frequency for each signal?

y-axis

Which of these is described as a horizontal line on the histogram that represents signal intensity that is proportional to X-ray exposure?

x-axis

If the captured values do not match the standardized histogram, the captured values are adjusted to match the standardized ones to display an acceptable image. This process is called:

automatic rescaling

The final step in digital image processing is to set the gray scale or contrast for the image. This process is accomplished by:

look-up table

The potential to gradually increase patient exposure over time because there are no visual cues for overexposure is called:

dose creep

Using the correct technical factors, collimation, and SID for the part allows the LUT to work correctly.

True

The ___ changes the numerical values of the pixels to the expected contrast levels for the anatomical part.

look-up table

Which of these is used to determine the approximate level of exposure to the IR since visual cues are usually not available?

exposure indicator

Which of these organizations has made a concerted effort to standardize exposure indicators?

American Association of Physicists in Medicine

The exposure indicator can have a direct or inverse relationship with receptor exposure.

true

The standard exposure indicator that can be used with all digital systems is called:

deviation index

Which of these devices calculates the dose by determining the entrance dose in centigray multiplied by the exposure field size for the image?

dose area product meter

As the number of pixels per square centimeter in the monitor increases, the monitor is able to display images at a higher resolution.

true

To display the gray scale in a radiograph, the monitor must be able to demonstrate at least ___ shades of gray.

256

The minimal requirement for a monitor's spatial resolution must be ___ when viewing a 14"x17" image.

2.5 lines per mm

What occurs when the electron beam intensity fluctuates as the beam scans back and forth across the back of the phosphor in the monitor?

temporal noise

The contrast resolution of a monitor is described as:

difference between the maximum and minimum luminance of the display

The minimal level of luminance is called:

the black level

Which of these terms refers to the number of times an image drawn on the screen refreshes?

refresh rate

A screen may display thumbnail images of the exams. This is called:

tiling

ACR standards require gray-scale monitors used for radiographic interpretation to provide a minimum of:

171 candela per square meter

Electronic markers applied during post-processing are not legal markers; markers must be placed during image acquisition.

true

The process whereby 2 images can be obtained, and then the software application melds the two images together to create one contiguous image is called:

stitching

Adjusting the window width is used to:

adjust the contrast on the monitor

Which of these describes a workstation software function that allows a black mask to be placed over bright areas on the screen:

shuttering

Specific numerical ranges assigned to pixels that contain the diagnostically useful information are referred to as:

values of interest

Which of these will provide the proper gray-scale, regardless of variation in kVp or mAs, resulting in consistent images?

look-up table

What is described as the distance from the center of one pixel to the center of the adjacent pixel on a radiographic monitor?

pixel pitch

The alternative term for noise is saturation.

false

Which of these can be the cause of grid cut-off?

improper SID

When an image shows signs of noise, what must be done to correct the image?

the image must be repeated with a higher mAs

___ is described as overexposure to the point where the dynamic range of the system can no longer accurately display the image data.

saturation

The purpose of the ___ is to reduce the amount of scatter radiaation reaching the image receptor.

grid

If a technologist fails to properly align the CR with the grid, what effect can result?

grid cut-off

What effect can occur when two exposures are made on one IR?

exposure field recognition error

The predominant cause of image blur is:

motion

Misrepresentation of the true shape of an object is referred to as:

shape distortion

The ___ is developed by the medical imaging department and is designed to produce quality images at acceptable doses.

target exposure index

Plate-based artifacts generally appear as ___ on the image.

white

The plate-based artifacts generally run along an entire plate axis and appear on nearly all images.

false

A hair stuck to one of the optics blocks the signal in that area and can cause an artifact with a ___ pattern.

wig-wag

Which of these is not true regarding artifacts in flat-panel DELs?

can be mitigated by cleaning the flat-panel detector array

An important standard that facilitates communication in medical imaging and establishes the software standards for exchanging electronic information in health care is called:

HL-7

The universally accepted standard for exchanging medical images among networked medical devices that was developed by the American College of Radiology is referred to as:

DICOM

The computer-based storage, retrieval, and viewing system for digital imaging examinations is called:

can be referred to as PACS or MIMPS

The ___ helps to distinguish one patient's data from another, reducing the chance for errors when choosing patient from worklist.

all of these are correct

2 multiple choice options

Diagnostic workstations used by the radiologist require high-resolution monitors that must have a display resolution of:

at least 2000 x 2000

A computer network limited to a relatively small area is referred to as a:

LAN

A network that utilizes a centralized computer that controls the operation of the network is called:

client/ server-based network

The device that connects multiple network segments is called:

network switch

The junction between two or more networks that allows data packets among the networks to be transported and buffered is called a:

router

What security device controls traffic between a single computer and a computer network with no security, or between a computer network in a trusted environment and a computer network in a less secure environment?

firewall

An image was created that showed a line that runs the entire length of the plate and parallel to the direction the plate travels through the reader. This artifact is contributed to:

a dirty light guide

What is the first thing that the technologist should do to correct a flat-panel DEL detector artifact?

recalculate the detector

A ___ network consists of 3 or more comuters that share resources and information.

network

Which of the following is a way that images in PACS can be accessed:

PACS images can be accessed in any of these options

2 multiple choice options

The maximum number of computer that cen be connected in a LAN is:

10

The difference between a bridge and a router is that a bridge uses the media access control to control data transfer, and the router uses an IP address.

true