flashcards

What refers to the rate of light striking a surface?

Illuminance

Who primarily uses diagnostic (primary reading) workstations?

Radiologists

What is used to monitor possible trends in imaging errors?

Repeat/reject analysis

What reason would cause an image to be suboptimal?

Poor collimation

What does the acronym RAID stand for?

Redundant array of independent disks

How does a dead pixel appear on a monitor?

White dots on a black background

How does a stuck pixel appear on a monitor?

Black dots on a solid white background

What is the specific name of the test pattern represented as SMPTE?

SMPTE

What holds the patient’s full medical information?

HIS

Which PACS quality control test ensures all images are successfully received by PACS?

Data integrity

What is performed when x-ray equipment is performing poorly?

Error maintenance

What describes the series of lines of unique data attached to every image?

DICOM header

Which of the following quality control issues is evaluated by checking that straight lines appear straight and the overall shape of the image is not distorted?

Geometric distortion

PSP plates should be erased every?

48 hours

What does teleradiology refer to?

Interpretation of medical images off site

What is the specific name of the test pattern represented as TG18-QC?

TG18-QC

Which PACS quality control test checks for loss of information on compressed images?

Compression recall

What describes spatial resolution when testing digital imaging IRs?

lp/mm - line pairs per millimeter

What type of compression results in no image degradation?

Lossless

What process describes a PAC system anticipating the need for previous images?

Prefetching

Which cannot generally be performed in PACS?

Stitch an image

What are the roles of a PACS image manager?

All of the above

What describes making copies of images to prevent loss during catastrophes?

Disaster recovery

What are the two main types of film digitizers?

Laser and CCD

What is a QC activity in a PACS environment?

All of the above

CQI focuses on _______ the process, while QA and QC programs focus on _______ quality.

Improving ; maintaining

What is a disadvantage of LCD monitors?

Limited off-angle viewing

What does the acronym PACS stand for?

Picture Archiving and Communication System

What does the acronym RIS stand for?

Radiology Information System

What does the acronym HIS stand for?

Hospital Information System

As the number of pixels on a monitor decreases, what happens to the resolution?

Decreases

What is assigned by RIS to identify a particular procedure?

Accession number

Which PACS quality control test assesses how quickly images are retrieved?

Image transfer speed

What PACS quality control test checks loading speed of a radiographic exam?

Workstation processing speed

What program monitors the performance of x-ray equipment?

QC

What tests are performed on newly installed equipment?

Acceptance testing

What tests ensure equipment performs as expected regularly?

Routine maintenance

What is a realistic target for an overall repeat rate?

3-5%

When should technologists notify managers of artifacts?

Immediately

What describes the monitor’s ability to display brightness shades from a test pattern?

Luminance response

What refers to the rate of light striking a surface?

Illuminance

What preprocessing function determines the number of images on a CR plate?

Segmentation (also known as PPR)

What describes a sub-matrix applied over a larger matrix to fill dead pixels?

Kernel

What best defines a histogram?

Graph where the x-axis is the pixel value and the y-axis is the number of pixels

What can negatively affect histogram analysis?

Collimation errors

What term describes a set of instructions in a computer program?

Algorithm

What is determined by finding the SMIN and SMAX of the histogram?

Values of interest

What is the correct definition of automatic rescaling?

Initial round of processes to make the image appear normal.

What describes corrections made to digital image data due to flaws in acquisition?

Pre-processing

What describes refinements made after corrections during post-processing?

Post-processing

What type of histogram analysis compares exposure to standardized data for abdominal x-ray?

Type 2

What type of histogram analysis is used in a barium study?

Type 3

What type of histogram analysis updates the reference histogram to a new ideal?

Neural

After the histogram is created, what is the area called that includes pixel values for the final image?

Values of interest

How many times the number of pixels must be sampled to form the image?

Two

Window level controls the overall ____________ of the image.

Brightness

What happens when the dels in a particular area of the IR reach maximum electrical charge?

Saturation

What is it called when a digital image is separated into a tissue only and bone only image?

Dual-energy subtraction

What is a correct statement about shuttering/cropping?

Can be used to remove the white border around an image.

Which speed class has less exposure to the receptor causing more noise?

400

What is the result when the slope of the LUT is increased?

Shorter scale of contrast

What is altered when the line of the LUT moves up or down on the graph?

Brightness

What describes amplification of high-frequencies to make edges stand out?

Edge enhancement

What best describes the intensity domain in processing?

Sorting the image strictly by pixel values

What best describes sorting by frequency in processing?

Sorting the image strictly by the size of objects

Which post-process option adjusts contrast of the image?

Window width

What post-processing function increases visible image noise?

High-pass filtering

What will most likely produce the highest quality radiographic image?

High SNR

What post-processing function is NOT acceptable?

Cropping exposed anatomical information from the image.

Which domain sorts objects according to location?

Spatial

What removes high-frequency noise?

Smoothing

As speed class increases, what happens?

The likelihood of noise increases

What may the use of smoothing result in?

Loss of fine detail

What does equalization primarily affect?

Contrast distribution

What is another name for smoothing?

Low-pass filtering

What has the greatest influence on displayed image contrast?

LUT

What parameter combines multiple images into one for display?

Image stitching

What describes the refinement of gray scale image by inputting data into lookup tables?

Gradation processing

What can cause a type 3 histogram to be produced?

Positive iodinated contrast or barium

How would a histogram appear for an image with a long scale of contrast?

The histogram would be wide.

What process is used to normalize an image regardless of exposure?

Automatic rescaling

What does the acronym TFT stand for?

Thin-film transistor

What does the pixel size formula apply to?

Soft image of a magnified image

What is made up of two metal oxide semiconductors?

CMOS

Which statement is true about CCDs and CMOS?

CCDs typically have a higher fill factor compared to CMOS.

In which type of digital radiography system are CCD and CMOS detectors used?

Indirect conversion

Which type of digital radiography detector contains full readout electronics within each detector element?

CMOS

What can cause artifacts in CR?

All of the above.

What type of CR reader captures light from both sides?

Dual-sided reader

What collects light released from the imaging plate in a CR reader?

Photomultiplier tube

What represents the latent image in a PSP CR system?

Electrons trapped in 'F' centers.

What refers to the immediate emission of light during stimulation?

Fluorescence

When red laser stimulation occurs in CR, what happens to electrons in F-centers?

They return to lower energy orbital shells, releasing light.

What describes the direction of plate movement through the reader?

Sub-scan (slow scan).

What describes the direction of laser beam movement across the CR imaging plate?

Fast scan.

Which term describes the percentage of absorbed x-ray energy converted into visible light?

Conversion efficiency.

What percentage is typically converted into electrical charge after x-ray or light photon absorption in a DEL?

Nearly 100%.

What concept states that sampling frequency must be at least twice the highest spatial frequency present in the image?

Nyquist frequency.

Which are considered scintillators EXCEPT:

Amorphous selenium.

What describes x-rays converting to light to electrical signals in flat-panel detectors?

Indirect conversion technology.