test 2

The ideal exposure range for a digital IR is

-30% to + 50%

Diagnostic interpretation by the radiologist should be done at a ___________ display monitor. a. 1 megapixel b. 2 megapixel c. 5 megapixel

5 megapixel

If a DI system can resolve line pairs as small as 0.2 mm, what is the spatial frequency? A. 5.0 line pair/mm B. 2.0 line pair/mm C. 0.4 line pair/mm D. 0.2 line pair/mm

5.0 line pair/mm

In DI, the graphic display of pixel values and counts is the image A. Matrix B Histogram C. Bit depth

histogram

In digital imaging, higher ___ techniques can be used to reduce patient doses A. kVp B. mAs C. SID D. OID

kVp

In order for you an exposure indicator number to be accurate at least ____ of the chosen CR plate must be exposed.

30%

The DI system with a ___ pixel bit depth will have the greatest contrast resolution A. 8 B. 10 C. 12 D. 16 E. 32

32

Which of the following changes in the exposure indicator values does not represent a doubling of radiation exposure to the IR? a. S number (Fuji) changing from 200 to 400 b. S number (Fuji) changing from 400 to 200 c. EI (Kodak/Carestream) changing from 1200 to 1500 d. EI (Kodak/Carestream) changing from 1500 to 1800

A

Define auto-rescaling

Adjustment of the electric signal to compensate for exposure error as determined by the histogram analysis.

Mathematical calculations used for DI construction are called A. logarithms B. algorithms C. interpolations D. extrapolations

Algorithms

The distracting area of increased brightness surrounding a collimated image (primary beam restriction) can be removed from the displayed digital image by: a. Black masking b. Shuttering c. Electronic collimation d. Black border e. All of the above

All of the above

The histogram generated from image data allows the system to find the A. Minimum signal (S1) within the VOI B. Maximum signal (S2) within the VOI C. Relative distribution of pixel values D. All of the above

All the above

In CR, the image must be converted into digital form by what device? A. Digital to analog converter B. Flux capacitor C. Analog to digital convertor D. DVD-ROM

Analog to digital convertor

Soft copy viewing means that the image is being viewed: a. At a computer b. On a soft piece of film c. In a soft light environment d. None of the above

At a comupter

Based on the histogram analysis, consistent image brightness is accomplished through: a. Adjustment of window width b. Automatic rescaling c. Manipulation of the exposure indicator d. Manipulation of the LUT

Automatic rescaling

CR plate phosphor crystals are most often___ with europium activators 1. BaSO4 2. BaFBr 3.BaFI 4. AgI

BaFBr & BaFl

CR plates are erased every morning mainly to eliminate the effect of A. Background radiation B. Scatter radiation C. Light leaks into the cassette D. Computer noise

Background radiation

Window level in digital imaging controls what image display property? A. Brightness B. Contrast C. Resolution D. Distortion

Brightness

A photostimulable phosphor is the active component in what piece of equipment? A. Intensifying screen B. Computed radiography imagining plate C. AEC chamber D. Fluroscopic screen

Computed radiography imagining plate

Window width in digital imaging controls what image display property? A. Brightness B. Contrast C. Resolution D. Distortion

Contrast

Boxes of laser film should be stored in a A. cool, humid area B. cool, dry area C. warm, humid area D. warm, dry area

Cool, dry area

When utilizing a DR system, if 2x the appropriate mAs is used, the result will be an image with ____ brightness and ___ contrast A. Correct, correct B. Excessive, correct C. Correct, low D. Insufficient, low

Correct, Correct

What is shuttering

Cropping or A workstation software function allows a black mask to be placed over bright areas.

The communication standard for medical images is: a. PACS b. HL7 c. DICOM d. RIS

DICOM

An IR that has a higher ___ has a higher probability of interacting with exit radiation (A)LET (B)TFT (C)SNR (D)DQE

DQE

What is used to measure an IR system's x-ray absorption efficiency? (A) Fill factor (B) Exposure data recognition (C) Detective quantum efficiency (D) Conversion efficiency

DQE ( detective quantum efficiency)

Increasing the window width of a DI while viewing it on the monitor will A. Increase image brightness B. Decrease image brightness C. Increases image contrast D. Decrease image contrast

Decrease image contrast

__________ is defined as the measure of x-ray absorption efficiency of an IR.

Detective quantum efficiency (DQE)

What type of DR system utilizes a-Seas a component of the detector element? (A) Direct conversion (B) Indirect conversion

Direct conversion

The readout obtained after an exposure is taken with DR equipment that indicates patient exposure is the _____

Dose are product (DPA)

The range of exposures over which an IR can adequately acquire image data is called the ____ range. A. Focal B. Pixel depth C. Dynamic D. Acquisition

Dynamic

This postprocessing technique improves the visibility of small, high contrast structures. a. Smoothing b. Contrast enhancement c. Edge enhancement d. Subtraction

Edge enhancement

What DI post-processing technique improves the visibility of small, high contrast structures? (A) Edge enhancement (B) Smoothing (C) Contrast enhancement (D) Subtraction

Edge enhancement

What postprocessing technique would be helpful in radiography of the AP thoracic spine?

Equalization

The exposure to a digital IR is represented by the numerical value called a/an A. Algorithm B. Exposure index C. Histogram D. Signal to noise ratio

Exposure index

The numerical value indicating the level of radiation exposure to the digital IR is the: a. VOI b. Histogram c. Exposure indicator d. LUT

Exposure indicator

In an indirect DR capture system, the absorbed x-ray photons are first converted to A. Fluorescent light B. Electrons C. Heat

Fluorescent light

What type of laser is used to scan the CR IPs? A. Fluorohalide B. Argon C. Helium-neon D. Cesium

Helium-neon

A graphic display that is constructed in digital imaging to show the radiographer the distribution of pixel values is a A. Algorithm B. Histogram C. Voxel D. Matrix

Histogram

The graphic display of pixel values is the _____

Histogram

How are pixel size and spatial resolution related? A. Directly- larger pixels = greater resolution B. Inversely- smaller pixels = greater resolution

INVERSLEY: Smaller the pixels=greater resolution

This post-processing function reverses the original gray scale values, changing the image from a negative to a positive one. a. equalization. b. flat-fielding. c. image reversal. d. subtraction.

Image reversal

Which of the following would reduce quantum noise in a digital image? 1. Decreasing mAs 2. Increasing mAs 3. Changing to a lower ratio grid a. 1 & 2 only b. 1 & 3 only c. 2 & 3 only d. 1, 2, & 3

Increasing mAs & Changing to a lower ratio grid

The type of DR detector that utilizes CSI and amorphous silicon is a ___ conversion A. Direct B. Indirect

Indirect

What type of IR system has the greatest DQE?

Indirect a:silicon flat panel DR detectors

CR plate erasure is accomplished by A. Light B. Electrons C. Heat D. Thermionic emission

Light

LCD stands for: a. Liquid cathode display b. Liquid crystal display c. Logarithmically created digitization d. Layered components diagram

Liquid crystal display

Describe the effect of kVp level on the width of the histogram.

Low kV gives a wider histogram, high kV gives a narrower histogram.

A digital image is composed of rows and columns known as a A. Matrix B. Pixel C. Voxel D. Histogram

Matrix

Compared with F/S IRs, digital receptors absorb ___ scatter radiation A. More B. Less C. The same quantity

More

The computer system designed to distribute, store, and display digital images is the _____

PACS

In the AUTO processing mode of a CR system how must the part and collimation edges be related to the IP?

Part and beam must be centered to the IP and even borders of collimation must be present.

______ occurs during CR plate processing when the trapped electrons are returned to a lower energy state. A. Luminescence B. Thermionic emission C. Analog to digital conversion D. Photostimulated luminescence

Photostimulated luminescence

A ______ is the smallest component of a digital image (A)Pixel (B)Voxel (C)Matrix

Pixel

___ is defined as the distance between the center of a pixel to the center of the adjacent pixel in a DR system DEL. A. Bit depth B. Window level C. Window width D. Pixel pitch

Pixel pitch

Adjustment of the digital signal to compensate for exposure error is called (A)Smoothing (B)Rescaling (C)Fixation (D)Enhancement

Rescaling

The minimum useful signal on a histogram is termed __

S1

The maximum useful signal on a histogram is termed ___

S2

In DR systems what parameters determine which DELs will be included in the image processing.

Selected FOV and collimation

How does underexposure affect the SNR and image quality?

Since the signal is very low, there is excessive noise compared to the useful signal. Image quality is low and the image demonstrates quantum mottle.

The postprocessing technique that is used to suppress image noise is called A.Smoothing B. Edge enhancement C. Contrast enhancement D. Subtraction

Smoothing

This postprocessing technique reduces the visibility of image noise. a. Smoothing b. Contrast enhancement c. Edge enhancement d. Subtraction

Smoothing

_ resolution is the ability of the system to display small high contrast structures accurately. A. Spatial B. Contrast

Spatial

This postprocessing technique can eliminate structures superimposing the structures of interest.

Subtraction

What DI post-processing function removes superimposing structures from the image? (A) Edge enhancement (B) Contrast enhancement (C) Black/white reversal (D) Subtraction

Subtraction

The relationship between useful and useless information an IR receives is called A. The fill factor B The DQE C. The SNR D. The algorithm

The SNR

Define Modulation Transfer Function (MTF)

The ability of a system to record spatial frequencies

The % of a flat panel detector's DEL that is able to absorb radiation (is the actual detector) is called (A ) the fill factor (B) the DQE (C) the SNR (D) the algorithm

The fill factor

How is the display matrix size related to image resolution?

The greater the matrix size, the greater the resolution

What compromise is made by a department that chooses to utilize only hard copy viewing of images?

The inability to utilize the dynamic range, cannot window and level.

Menu selection of the anatomical part and view chooses the algorithm- define algorithm.

The mathematical formula used to construct the histogram

The CR reader component that converts the released light into electrons is the (A)Beam shaping optics (B)The ADC (C)The laser beam (D)The photomultiplier tube

The photomultiplier tube

Define Exposure Field Recognition.

The process in CR where the system first scans the entire plate in order to locate the clinically useful information.

Define signal to noise ratio (SNR).

The relationship between useful information (signal) representing anatomy and useless information (noise).

What is represented on the vertical (y) axis of the histogram?

The total number of each specific pixel value

What is represented on the horizontal (x) axis of the histogram?

The various pixel values (shade of gray

Most laser film must be handled A. under a Wratten 6B safelight B. in total darkness C. under a GBX safelight D. with high-temperature chemical processors

Total darkness

Direct digital radiography systems eliminate the EFR step. True / False

True

Dry laser printers use heat to print the image. A. True B. False

True

DI image noise results mostly from A. Overexposure B. Underexposure C. Use of low ratio grids D. Excessive OID

Underexposure

In digital imaging, quantum mottle is a result of A. underexposure B. overexposure C. histogram error D. incorrect collimation

Underexposure

What choice can you make as an imager in cassette selection when utilizing a CR system to produce the greatest spatial resolution?

Use the smallest size CR plate that will include all the structures of interest.

During laser scanning of a CR IP, the stored energy is released in the form of A. Electrons B. Visible blue light C. visible red light D. Heat

Visible blue light

What is image stitching

When anatomy or the area of interest is too large to fit on 1 cassette, multiple images can be "stitched" together using specialized software programs

A change in the __________ will result in an image with a change in image brightness.

Window level

This post-processing function allows the viewer to adjust the image brightness and/or contrast. a. edge enhancement b. image reversal c. subtraction d. windowing

Windowing

The SI unit used to specify DAP is the

dGy/cm2

The AAPM has proposed adoption of a universal exposure indicator value called the_____ _____.

deviation index

Which of the following is not accomplished through the histogram analysis? a. Compensation for image over or underexposure b. Identification of borders of collimation c. Comparison with a LUT d. Determination of S1 and S2 values e. All of the above occur during histogram analysis

e

Higher DQE image receptors can result in ________ patient doses. A. Higher B. Lower

lower

Increasing the window width will result in an image with: a. Lower contrast b. Higher contrast c. Decreased brightness d. Increased brightness

lower contrast

The unit of spatial frequency that is used to specify spatial resolution is A. micrometers B. MTF C. lp/mm D. Hertz

lp/mm