Exam 4 Image Production Review (51 Questions) Equipment Operation and Quality Assurance (21 Questions)

What is the type of phosphor used in CR?

barium fluorohalide doped with europium

what is Latent image

an invisible image

what is a manifest image

the visible image

What happens in the active/phosphor layer?

absorbs the xrays, where the electrons are trapped

What pattern does the laser scan in?

raster

What controls the laser and how it hits or is spread over the CR plate?

beam shaping optics

What color of light is emitted when the laser hits the trapped electrons?

blue

What is the role of the photomultiplier in CR technology?

detects the blue light and coverts it to electrical signal

What does the analog to digital converter (ADC) do?

Transforms the electrical signals generated by the scanner into digital format

How is the CR plate erased?

Fluorescent light

What is a ghost error on a CR plate?

An image that was not properly erased

How long can the latent image last on the CR plate before it starts to fade?

Within the hour

How often should you erase the CR plates when they have not been used lately?

Every 48 hours

What is a Moire pattern?

When grids are not aligned properly

What will dust look like on a CR plate?

Image artifacts

what has scintillator?

indirect

what has photodiode?

indirect

what has a photoconductor?

direct

Which one uses amorphous silicon?

indirect

which one skips the scinallotor?

direct

Which one uses amorphous selenium

direct

In a TFT array, what is the fill factor?

The area of the detector that is sensitive to x-rays

What is the difference between analog and digital?

Analog measures continuous signal, digital measures numeric values

What is spatial resolution?

The ability to see the smallest objects on the image

What does Pixel stand for?

Every tiny square that makes up an image

The number of pixels depends on the size of the _______________?

Matrix

Do we want a small matrix or a large matrix?

Large matrix

If the matrix size gets larger, how will that change the size of pixels?

Smaller

Would large or small pixels improve spatial resolution?

Small

What is pixel density?

A number of pixels per unit area

What is pixel pitch?

Distance measured from the center of a pixel to the adjacent pixel

What is a DEL?

A small individual component within a x-ray detector that detect and converts x-ray photons to signal

Does DEL size in a DR TFT array impact spatial resolution?

Yes

What is contrast resolution?

The ability to distinguish between subtle differences in color or brightness

Define dynamic range

The range of exposure that can be captured by detective

Define exposure latitude

The range of exposures that can be recorded as useful densities

What does the term gross exposure error mean

A significant mistaken, the amount of radiation used during an x-ray

how does quantum mottle image appear? is it too much or too little exposure?

Salt and pepper, two little

how does a saturation picture look? Is it too. much or too little exposure?

Too much

What is the Exposure Indicator

A numerical value used to provide information about dose

What does the EI tell us

How much dose

Do all manufacturers use the same EI indicator?

No

How does mAs relate to the number of x-ray photons in the x-ray beam (Quantity)?

Same thing

How does mAs affect the Receptor Exposure?

Increases

Will increasing kVp affect the Receptor Exposure?

Increases

Will increasing the kVp increase the beam energy?

Yes

Will increasing the kVp increase the beam penetrability?

Yes

Will using the 15% rule impact receptor exposure?

Yes

Define Bit Depth:

The total number of possible shades of gray that can be assigned to a pixel

When does Quantization take place?

ADC

Define the Quantization process:

Energy is converted to analog electrical signal

Increasing Bit depth will have an impact on which factors?

Determines the level of brightness and contrast

Define Histogram:

A visual representation of the images exposure

What is displayed on the X-axis? What is displayed on the Y-axis?

X – exposure values

Y – numbers of occurrence

Describe Histogram Analysis Value of Interest (VOI)

The specific range of pixel intensity values

What does the term “raw image” mean?

Unprocessed digital data

Define Rescaling:

Aims to maintain consistent image, brightness, and contrast

Define Look-up Table (LUT):

A table that maps input values to output, value values

Does correct collimation have an impact on Histogram analysis?

Yes

Is it important to process the image under the correct anatomy selection on the control panel?

e.g. Should you process a chest under a foot setting?

Yes

Define annotation:

labeling the image

Define cropping/masking:

The process of selecting and removing portions of the x-ray

Define stitching:

Bringing multiple images together

Define region of interest (ROI):

A subset of an image or volume that is chosen for a particular purpose

Define window level:

Brighter or darker

Define window width:

White or black

What contrast does a narrow window provide?

more contrast

What contrast does a wide window provide?

Less contrast

Define edge enhancement:

Sharpen edges

Define smoothing:

Averages pixels

Define equalization:

Amston improve image quality by adjusting exposure levels

Define Modulation Transfer Function (MTF):

The ratio of contrast of an image to the original image

What is the perfect or ideal MTF?

One

Define Detective Quantum Efficiency (DQE):

How efficiently system converts photons into image

Define Signal-to-Noise Ratio (SNR):

Measures the strength of true signal relative to background noise

Do you want a high or low SNR?

High

Which one will provide the least image noise? (HIGH OR LOW)

Low

Define Sampling Frequency (CR):

How often data is used to create images

How does it relate to spatial resolution? (Sampling Frequency)

Over sampling too much information under sampling lack of resolution

What patient identifiers must be included on a radiographic image?

Name, date of birth, date of exam, location, right or left marker

What does PACS stand for?

Picture archiving and communication system

Define DICOM:

Digital imaging and communication, communications and medicine

Define EMR:

Electronic medical records

Define EHR:

Electronic health record

How is the EMR different from an EHR?

EMR is single provider, EHR is multiple providers

What does HIS stand for? What does it do?

Hospital information system holds all administrative stuff

What does RIS stand for? What does it do?

Radiology information system, workflow management

How do HIS and RIS communicate?

HL7

What is Teleradiology?

Remote transmission and interpretation of images

What are the two main components of a PACS system?

Archive, image manager

What viewing angle to the monitor is the best?

90°

What is the SMPTE test pattern?

Evaluate the quality of imaging monitors, and record recorders

What is the importance of luminance levels - how is luminance tested

Crucial for imaging visualization

what are the steps for CR?

Image acquisition, reader, display

What is the protective layer do?

Protection of phosphate layer

What does phosphate layer do?

Traps electrons

What does light reflective layer do?

Send light forward, detailed lost

What does conductive layer do?

Absorbs and reduces static

What does support layer do?

Semi rigid material that gives imaging sheet some strength

What does backing layer do?

Protect against backscatter