Image Production Boards

Front 1

Anatomic Alignment

Back 1

Since the amount of radiation required to produce a quality, diagnostic radiograph depends on the cell selected, careful positioning and central ray centering is required when using AEC techniques.

Front 2

Spatial Resolution

Back 2

The ability of the system to record adjacent small structures, equipment related.

Front 3

Pixel

Back 3

Picture element; smallest component of the matrix

Front 4

Pixel pitch

Back 4

The pixel spacing or distance measured from the center of a pixel to the center of an adjacent pixel.

Front 5

Pixel Size

Back 5

The measure of the pixel from end to end

Front 6

Pixel Density

Back 6

Number of pixels per unit area (millimeter)

Front 7

Matrix

Back 7

Combination of rows and columns of pixels that make up a digital image.

Front 8

CNR

Back 8

As noise increases it is more difficult to visualize low contrast objects.

Front 9

Affected Focal Spot Size is....

Back 9

always bigger than the effective focal spot size bc more photons are hitting it.

Front 10

The anode is made of...

Back 10

Tungsten

Front 11

The anode base is made of...

Back 11

Copper, molybdenum, or graphite.

Front 12

Induction motor operate the...

Back 12

Rotor that spins the anode.

Front 13

Isotropically

Back 13

Produced with equal intensity in all directions. Fact: xray beams are isotropic.

Front 14

Leakage Radiation

Back 14

Photons produced in the X-ray tube that are traveling in all directions other than toward the patient. (Emitted through the metal protective housing of the tube)

Should not exceed 100mR/hr at 1 meter.

Front 15

AEC relies on...

Back 15

Effective and accurate patient positioning and photo time cell selection.

Front 16

AEC is NOT

Back 16

Intended to be a means of primary termination of exposure. PT safety device in case machine malfunctions.

Front 17

Minimum Response Timer (MRT)

Back 17

The time is takes for a system to respond and send the signal to terminate the exposure.

Front 18

Sampling Frequency

Back 18

The number of pixels sampled per millimeter as the laser scans each line of the imaging plate.

Front 19

Aperture Diaphragm

Back 19

Simplest type of beam restricting device. Lead plate with hole cut in the middle that is smaller than the IR size.

Front 20

Variable Aperture Collimators

Back 20

Beam restricting device that can be controlled by the radiographer. Utilizes a light-localization device to estimate the size and shape of the radiation field.

Front 21

Cylinders and Cones

Back 21

Beam restricting devices that attach to the bottom of the collimator housing. Creates circular shaped collimation.

Front 22

Collimation

Back 22

Most common type of beam restricting method.

Front 23

Electrical energy supplied to the xray unit is?

Back 23

Alternating Current (AC)

Front 24

Induction requires..

Back 24

AC current

Front 25

Transformers operate on the principle of?

Back 25

Electromagnetic induction and require AC current to operate.

Front 26

Self Induction

Back 26

The changing magnetic field that is created by inducing an opposing voltage in a single coil of wire.

Front 27

Mutual Induction

Back 27

Inducing a current through a secondary coil by varying the current through the primary coil.

Front 28

Electromotive Force (EMF)

Back 28

Voltage

Front 29

Increasing the sample frequency...

Back 29

Results in the laser moving a smaller distance and there is an increase in spatial resolution.

Front 30

Shell Core

Back 30

Type of transformer. Most efficient and commonly used of the transformers.

Front 31

Types of transformers:

Back 31

Air Core, Open Core, Closed Core, and Shell Core.

Front 32

Autotransformer

Back 32

A single coil conductor material acts as both primary and secondary sides of the autotransformer. Purpose is to determine the amount of line voltage that will be sent to the step-up transformer. Operates on Self Induction.

Front 33

What is the source for KVP?

Back 33

Autotransformer

Front 34

Step-up Transformer aka (high voltage transformer)

Back 34

Separates xray circuitry into primary or low voltage and secondary or high voltage sections. Operates on mutual induction. Converts low voltage from the secondary side of the autotransformer into the high voltage or KV required to produce an xray in the tube.

Front 35

Filament transformer (aka low voltage or step down transformer)

Back 35

Takes care of thermonic affect. Operates on mutual induction.

Front 36

mA station

Back 36

Selected by the rad tech, determines the amount of current and voltage sent to the primary side of the filament transformer. (Varies the level of resistance)

Front 37

Pre-reading KVP meter

Back 37

Read voltage, NOT KILOvoltage.

Front 38

Mechanical Exposure timer

Back 38

No longer in use

Front 39

Synchronous Exposure Timer

Back 39

Capable of exposure times in multiples of 60

Front 40

Nyquist Frequeny

Back 40

is the relationship between the sampling frequency and the spatial resolution.

Front 41

Electronic Exposure Timer

Back 41

Complex, accurate up to 1 millisecond. (Most accurate)

Front 42

mAs (exposure timer)

Back 42

Establishes the highest, safest mA at the shortest exposure time.

Front 43

AEC exposure timer

Back 43

Utilizes an ionization chamber placed between the patient and the image receptor.

Front 44

mA Selector

Back 44

Variable resistance

Front 45

Focal Spot Selector

Back 45

Purpose is to select the size of the filament within a dual filament X-ray tube that will be used to produce a source of free electrons. (Can withstand heat)

Front 46

In the U.S., electrical energy is supplied in 60-cycle alternating current.

Back 46

Each Cycle consists of 2 pulses of electric current, with the pulse going in the opposite directions. 1 cycle= 2 pulses= 2 alterations of electric current.

Front 47

Rectifiers

Back 47

Devices that convert alternating current into direct current.

Front 48

Half wave rectification

Back 48

The negative pulse of each cycle of alternating current is prevented from going across the X-ray tubes.

Front 49

Full wave rectification

Back 49

The negative pulse of current is redirected through a series of valve tubes in order to be applied to the cathode side of the X-ray tube.

Front 50

High frequency

Back 50

Voltage ripple is 1% since the voltage waveform is nearly constant.

Front 51

Contrast Resolution

Back 51

The ability to detect subtle changes in the grayscale.

Front 52

Image intensifier function

Back 52

To convert the xray beam into a bright visible light.

Front 53

Input phosphor

Back 53

Converts the incoming xray photons. Typically made of cesium iodide.

Front 54

Photocathode

Back 54

Converts light photons from the input phosphor into free electrons.

Front 55

Anode

Back 55

Allows the electrons to pass through the output phosphor.

Front 56

Output Phosphor

Back 56

Converts electrons sent from the photocathode into light photons. Typically made of zinc cadmium sulfide.

Front 57

XLELM

Back 57

Xrays-light-electrons-light-monitor

Front 58

Brightness Gain

Back 58

The expression of the ability of an image intensifier tube to convert xray energy into light energy and increase the brightness of the image in the process.

Front 59

Cone Cells

Back 59

Bright light vision (phototopic)

Front 60

Rods Cells

Back 60

Low light or night vision (scotopic)

Front 61

Vignetting (Pin Cushion Distortion)

Back 61

The apparent loss of detail and fall off of brightness along the edge of the flouroscopic image.

Front 62

DEL (detector element)

Back 62

Size is used with direct capture radiography (cassette less). Spatial resolution is determined by the DEL. As the DEL increases, spatial res decreases.

Front 63

Cine Fluoroscopic Device

Back 63

Exposed by light from the output end of the image intensification tube. Gives highest pt dose.

Front 64

Automatic brightness control (ABC) or Automatic Exposure Rate Control (AERC)

Back 64

A function of the fluoroscopic unit that maintains the overall appearance of the image by automatically adjusting the KVP, mA, or both.

Front 65

Magnifying the fluoroscopic image results in...

Back 65

Increased patient dose, but yields better spatial resolution and better contrast resolution.

Front 66

Fluoroscopy is the...

Back 66

Single greatest source of acute radiation exposure to the patient in the diagnostic radiology environment.

Front 67

Cassette Based (digital detectors)

Back 67

Photostimuable phosphor plate (PSP)

Front 68

Cassetteless (digital detector)

Back 68

Flat panel detector/thin film transistor (FPD/TFT)

Front 69

Phosphor or Active Layer

Back 69

This layer contains the photostimuable phosphor that “traps” electrons during the radiographic exposure.

Front 70

Violet light is viewed by?

Back 70

A very sensitive photomultiplier

Front 71

S or Sensitivity Numbers

Back 71

have an inverse or indirect relationship to the amount of exposure.

Front 72

EI or Exposure Index

Back 72

Has a direct relationship to the amount of exposure.

Front 73

quantum mottle

Back 73

Type of noise that results when too few xrays reach the IR causing the image to be underexposed. (Contrast loss)

Front 74

Lgm or logirithum

Back 74

Median exposure has a direct relationship to the amount of exposure.

Front 75

Flat panel detector: indirect

Back 75

scintillator based systems use cesium iodide (CSI) or gadolinium oxysulfide. The scintillator converts xray photo into light photons.

Front 76

Flat panel detector: direct

Back 76

Non-scintillator based system. This system uses amorphous selenium (a-Se), which converts the xray beam into electrons.

Front 77

Charged couple device (CCD)

Back 77

A light sensitive semi-conducting device that generates an electrical charge when stimulated by light and stores this charge in a capacitor.

Front 78

Complimentary Metal Oxide Semiconductor (CMOS)

Back 78

A scintillator device made of a crystalline silicon matrix.

Front 79

Low S

Back 79

Overexposed

Front 80

High S

Back 80

Underexposed

Front 81

Analog to digital converter (ADC)

Back 81

A device that takes the analog signal and divides it into a number of bits that the computer “understands.”

Front 82

Histograms

Back 82

Used to represent a graphical representation of optimal densities during an exposure, and recognition of exposure data requires processing only by optimal receptor exposure exposures.

Front 83

Rescaling

Back 83

A digital reprocessing technique that is used to modify an overexposed or underexposed image.

Front 84

Contrasts Resolution/Dynamic Range

Back 84

The range of exposure intensities that an image receptor can respond to and squire image data. Greater dynamic range will yield in greater contrast resolution.

Front 85

Equalization

Back 85

Method of image processing using the histogram of the image to adjust contrast. To improve image display range.

Front 86

Electronic Collimation

Back 86

Masking (Subtraction)

Front 87

Stitching

Back 87

Computer programs an “stitch” images together to combine multiple images for anatomy that is too large for a single exposure.

Front 88

Shuttering

Back 88

Removes or replaces the background

Front 89

Spatial Resolution

Back 89

Ability to distinguish between adjacent objects on the radiographic image. (Small recorded detail)

Front 90

Windowing

Back 90

Ability to alter the receptor exposure and contrast of a digital image following processing.

Front 91

Hounesfield unit

Back 91

Value related to the attenuation characteristic of the tissue in the voxel but not an attenuation coefficient.

Front 92

FOV

Back 92

Diameter of the image reconstruction.

Front 93

Window leveling

Back 93

Determines brightness

Front 94

Window width

Back 94

Determines the gray-scale, image contrast.

Front 95

Signal to Noise Ratio (SNR) AKA Contrast Noise Ratio (CNR) or Signal Difference to Noise Ratio (SDNR)

Back 95

Ratio between “signal” or meaningful information and “noise” or background. (The more signal, the greater the spatial resolution)

Front 96

Wider window widths

Back 96

Results in long gray scale (low image contrast)

Front 97

Narrow window widths

Back 97

Produce a narrow gray-scale (high image contrast)

Front 98

Digital imaging and communication in medicine (DICOM)

Back 98

Accepted standard for networked medical devices to exchange the images and information.

Front 99

Picture archival and communication system (pacs)

Back 99

Consists of digital acquisition equipment, workstations for display and manipulation of images and interconnected storage devices that communicate over a network in the same language.

Front 100

Teleradiology

Back 100

Process of remote transmission and viewing of images.

Front 101

Hospital Information System (HIS)

Back 101

Contains full patient information

Front 102

Radiology information system (RIS)

Back 102

Contains radiology specific information about a patient including the radiologist’s report.

Front 103

What is the amount of change in mas necessary to yield a noticeable difference in receptor exposure change within the radiographic image?

Back 103

30%

Front 104

SNR

Back 104

As noise increases it is more difficult to visualize small objects.

Front 105

The five things that must be present on a radiograph are:

Back 105

1) Pt Name

2) PT ID #

3) Markers

4) Exam date

5) Institutional Name

DOB and DIGITAL markers are not mandated.

Front 106

Dynamic Range

Back 106

The range of exposures that can be captured by a receptor.

Front 107

Exposure latitude

Back 107

The range of exposure that produce quality images at an appropriate patient dose.

Front 108

Quantization

Back 108

Is the process of turning electrical signal into a DIGITAL image.

Front 109

Bit Depth

Back 109

The total number of possible brightness levels that an be assigned to any given pixel in the digital image.

Front 110

Histogram

Back 110

Frequency of recorded exposures. (Graph form)

Front 111

Rescaling

Back 111

Adjusts histogram to expected values. This makes of for any small technique errors the tech may have made.

Front 112

Histogram analysis

Back 112

Identifies the values of interest (VOI)

Front 113

Look Up Table (LUT)

Back 113

used to correct brightness and contrast

Front 114

Correct body part and correct collimation = ?

Back 114

The correct histogram processing.