RAD 200 Final Review

Occurs when the focal point in the intensification tube is moved closer to the input phosphor

The input phosphor of the image intensifier is made of this material

Fuji’s S number is the oldest exposure indicator.

The part of the image intensifier thats responsible for guiding electrons from the photocathode to the output phosphor

Digital imaging systems have poor contrast resolution

With an LCD monitor, when no electrical current is applied, the pixels are in the ____ state

Histogram analysis error can result in a image that is too light,too dark,with excessive grayscale or excessive contrast

Processing domain that works best for suppressing quantum mottle.

Records the light image from the output phosphor of the image intensifier 

Which part of the histogram is used to calculate the exposure indictor?

This device measures discrete data.

Which imaging system has the best spatial resolution?

The proper way to store lead protective devices

The ability to repeat the same overall technique settings and obtain the same results in actual exposure

The individual square cells within an image matrix are:

With regards to frequency processing, which of the following statements is true?

Frequency processing alows us to select a specific frequency layer to boostor suppress prior to reconstructing the image

The purpose of gradation processing is to compensate for image acquisition flaws.

Compresses the image data so that when the compression is reversed the original data set is fully recreated.

With regards to frequency processing, large objects have

The distance from the center of one pixel to the center of the adjacent pixel is pixel wavelength

The acceptance parameters for this QC test is + or – 2% of the SID

Represents a flat, black area with absolutely no details present.

Form of low-pass filtering that softens edges and reduces noise

PACS

The direction of CR plate movement through the reader

Which of the following are advantages of dynamic flat-panel detectors as compared to image intensifiers

What are the advantages of using CMOS instead of a CCD

As an image intensifier ages, contrast can deteriorate as much as ____% per year.

Defined as the number of gray shades with which each pixel can be represented by the system

Additional gradation occurs after noise reduction and detail processing operations

Assists in maintaining image brightness as a patient rolls onto his/her side during dynamic imaging

The post processing operation that separates the image into tissue only and bone only images

The part of the dexel responsible for storing electric charge

An advantage of digital imaging is its ability to amplify gray scale values without re-exposing the patient.

Random access memory is associated with temporary memory.

Which change will result in less patient dose?

The most common method to correct for a dead detector element is by using a software kernel.

Gradient processing is only applied during default processing when anatomical LUTs are applied

A generic, universal test template used to evaluate electronic display systems

For a given physical size, the larger the matrix size, the ______ the pixels.

All computer instructions are in binary code, a power of 10 notation. 

A bar graph that indicates the number of pixels counted for each gray level

The common approach to determining ranges of acceptable exposure is to allow from ___ to ___ times the target exposure.

How does pixel size impact spatial resolution?

This system results in less patient dose due to the amplifying effect of converting x-rays into light

You can decrease overall image brightness by:

A bit has two potential values: 0 or 1

The net result from unsharp mask filtering is:

Band pass filtering is named after what frequencies it keeps in the reconstructed image.

Insufficient techniques can cause ___ in the image

When using a c-arm less scatter is delivered to the operator by placing the image intensifier:

This occurs if the dynamic range is too limited

If the target for an inversely proportional EI system is 200, a relative exposure of 100 indicates the exposure was:

Defined as a sub-matrix that is passed over a larger image matrix to execute a mathematical function

The maximum ambient light for a diagnostic reading room

If an image re-processed under a different algorithm is saved into PACS

The range of different gray levels for a computer

Device responsible for converting digital data to analog data

The CR phosphor layer responsible for blocking laser light from reaching the next layer

What is the digital radiography controlling factor for sharpness

Which of the following is the most sensitive to background radiation

With logarithmic exposure indicator scales, a change of 0.3 represent a change in exposure of

What is the digital radiography controlling factor for brightness

Range of different gray levels made available by a computer system including its installed software

If ½ the speed is used, how should exposure be adjusted to maintain IR exposure?

A pre-programmed set of instructions for a specific task:

Which matrix size will have the lowest spatial resolution?

Managerial philosophy that ensures excellence in healthcare.

Results in severe mottle

What is the digital radiography controlling factor for gray scale

Expresses an imaging systems sensitivity to radiation

The rate of light striking a surface

Artifacts that tend to be of roughly consistent size and occur in a regular pattern are types of

Anything that leads to histogram errors can result in an inaccurate exposure index number

With regards to frequency processing, small objects have

Fourier transformation is the process of reconstructing an image after frequency processing has been completed

Defined as the difference in intensity between two different tissue areas divided by the background noise level

For digital systems, the maximum spatial resolution is equal to the Nyquist frequency

The fluoroscopic exposure output when operating in normal mode should not exceed:

Customizes the gray scale and brightness according to the specific anatomy being demonstrated

A measure of spatial resolution with a unit of lines pairs/mm.

Dynamic range compression creates a grayer-looking image

The most important invention to the development of computer hardware

The ratio of the input phosphor area to the output phosphor area

The number of output photons divided by the number of input photons

Used to measure the light intensity from a display monitor

Which will provide higher contrast resolution and better spatial resolution

Range of different gray levels present in a displayed image

This is an example of a process using intensity operation processing.

The first step to digitizing an analog image is to sample the intensity of light or radiation for each cell.

High pass filtering allows ___ frequencies to pass through to the final image and results in ____.

The longer the gray scale, the more details that can be represented in the image.

Defined as the maximum number of pixel values the computer can store.

Excessive edge enhancement can result in:

The detector surface material for a direct exposure system

Saturation can be corrected by windowing

Provides a continuous output image for examination after exposure

Histogram analysis failure is more common with DR systems

Which systems undergo more preprocessing?

What are the 3 types of spatial domain processing?

Objects are sorted by their size in this processing domain

Identify the factors that impact field uniformity.

Reverses blank areas around the image to black border

The artifact associated with incomplete erasure of the CR phosphor plate

An exposed CR plate will retain what percentage of the image even 8 hours after exposure?

An interference pattern or false presentation of artifactual lines

This type of processing executes a function on a subsection of the image: i.e. zoom

This processing function decouples local contrast from global contrast

Example(s) of application software include:

The computer language that specifies the transmission behavior of images/image data from medical devices

Radiologists are required to read images using a class 2 workstation.

When are procedural algorithms engaged?

If a body part covered the entire IR plate, the acquired histogram would only have the main lobe

Partitioned pattern recognition is only necessary in DR imaging

During rescaling the computer roughly corrects for image brightness.

Momentary defects in the distribution of brightness in a dynamic image

You can increase the gray scale by:

Provides remote transmission & viewing of radiographic images.

What causes the presence of a tail lobe in a histogram?

How many bits are there in one byte?

What is the weakest link in the imaging chain

Smoothing, edge enhancement, and background suppression are processing results created by application of a kernel 

The processing feature that results in clipping off of the extreme ends of the gray scale.

Which methods will reduce patient exposure during dynamic imaging?

CR phosphor absorption efficiency is increased by:

An image with a deviation index of greater than 3.0 should always be repeated.

A type of distortion that results in a loss of brightness toward the periphery of the image

Re-mapping the brightness and gray scale of an image so that is appears “normal”

Image analysis step that removes pitch black background densities from x-ray exposure outside anatomy

Defined as the range of pixel values actually present in a displayed image.

Every image begins and ends in the intensity domain

What is the major disadvantage of an LCD monitor compared to a CRT monitor

Which imaging systems has the highest DQE

Once brightness has been adjusted on a Fuji system, the S number cannot be used as an exposure indicator

This part of the computer directs the flow of data from primary memory to other devices.

The part of the computer that interprets & executes instructions: