Imaging Iii Midterm 4

Front 1

Major difference between direct and indirect conversion

Back 1

Direct has photoconductors

Indirect has scintillator

Front 2

Active-Matrix Flat-Panel Image Receptor (AMFPI)

Back 2

Uses flat-panel array with x-ray absorption material - photoconductor or scintillator

Front 3

Photoconductor

Back 3

Absorbs x-ray, resulting in an electrical charge

Front 4

Scintillator

Back 4

Absorbs x-ray and produces light

Front 5

TFT

Back 5

Thin-film transistor; photosensitive array of pixels, each pixel absorbs electrons & generates electrical charge

Front 6

FET

Back 6

field effect transistor - isolates each pixel and sends electrical charge to image processor

Front 7

Amorphous selenium

Back 7

What the photoconductor is made of; material that absorbs x-rays and converts them to electrons

Front 8

What is the two step process in indirect conversion?

Back 8

X-rays are converted to light

Light is converted to electronic signal

Front 9

Two types of indirect detectors

Back 9

Flat-panel TFT detector

Charge-coupled device (CCD)

Front 10

What two phosphors may be used in the scintillation layer?

Back 10

Thallium doped cesium iodide

Gadolinium oxysulphide

Front 11

Which type of amorphous silicon detector is most popular?

Back 11

CsI (Cesium iodide)

Front 12

Characteristics of CsI flat-panel detector

Back 12

Very thin needles

No light spread

High DQE, spatial resolution

Front 13

Which has better spatial resolution?

Flat panel detector or imaging plate

Back 13

Flat panel detector

Front 14

Smaller imaging plates have _____________ spatial resolution than larger imaging plates

Back 14

Better

Front 15

Both direct and indirect conversion methods are types of

Back 15

TFT flat-panel technology

Front 16

Fill factor

Back 16

Expressed as a percentage of sensitivity ???

Front 17

DEL

Back 17

detector element - makes up the matrix of a flat panel detector, collects electrons that represent exposure level

Front 18

Size of DEL determines

Back 18

spatial resolution

Front 19

Dead pixels

Back 19

Defective pixels caused by dust, scratches, static discharge, chemical corrosion etc

Malfunctioning or not functioning

Front 20

Gain calibration

Back 20

Used to correct flaws in detector (if an area has large amount of dead pixels or poor connections, gain calibration removes unwanted densities leaving only diagnostic info

If this fails it will create an artifact

Front 21

Image lag

Back 21

Faint image from previous exposure; detector hasn't erased fast enough

Front 22

Reasons image lag may occur

Back 22

Rapid succession of images

Overexposure

An area with little beam attenuation (marker)

Front 23

How to reduce possibility of image lag

Back 23

Increase time btwn exposures

Reduce amount of unattenuated beam by collimating

Use appropriate technical factors, take image with highest technical factors last

Front 24

Offset correction

Back 24

Determines amount of signal inherent in the detector

Can be used to correct image lag

Front 25

Oldest type of indirect conversion

Back 25

CCD (charge-coupled device)

Front 26

4 components of a CCD

Back 26

Scintillator

Mirror

Focusing lens

Integrated circuit device

Front 27

How does CCD differ from photostimulable phosphor and flat panel devices?

Back 27

Requires scintillator or other material to produce light

Front 28

What reduces image size in CCD?

Back 28

Fiber optic

Front 29

CCD is a ______ sensitive device

Back 29

Light

Front 30

CCD converts ______ energy to ______ signal and then ?

Back 30

Converts light energy to electronic signal and sends to computer

Front 31

Bucket brigade scheme

Back 31

Moving of electrons by rows down columns until readout is reached

Front 32

Blooming

Back 32

Spillover of electrons from a DEL into another

Front 33

Advantages of CCD

Back 33

Inexpensive

Simple

Easy to repair/replace/upgrade

Modular design

Front 34

Disadvantages of CCD

Back 34

Demagnification issues

Reduced DQE

Front 35

The size of most CCD chips ranges from

Back 35

2 to 4 cm

Front 36

What do lenses and fiber optics do within CCD systems?

Back 36

Focus light onto the chip, reduce image size

Front 37

DQE

Back 37

Amount of electrons produced relative to incident light from scintillator

Represents efficiency of light collection & signal created in chip

Front 38

Types of noise associated with CCD technology

Back 38

Statistical noise

Dark current noise

Amplification noise

Front 39

Statistical noise

Back 39

Noise created by lack of light photons from the scintillator

Either not enough x-ray photons striking the scintillator or not enough light photons being produced by the scintillator

Front 40

Dark current noise

Back 40

Occurs when CCD chip operates w/o radiation stimulation

Happens when temperature rises

Front 41

Amplification noise

Back 41

Due to variations in chips from manufacturing process, not every chip comes out the same

Some have dead/bad pixels - cheaper chips have more defects

Front 42

What are some applications CCDs may be used in?

Back 42

Digital fluoro

Stereotactic breast biopsy

Digital mammo

General radiography

Front 43

CMOS

Back 43

Complimentary Metal Oxide Semiconductor

Front 44

What does a CMOS system do?

Back 44

Uses scintillator to convert x-rays to light & stores in capacitors

Front 45

Semiconductor

Back 45

Solid chemical element/compound that conducts electricity under some conditions but not others

Front 46

CMOS or CCD more susceptible to noise?

Back 46

CMOS

Front 47

CMOS OR CCD - which has lower light sensitivity within the chip?

Back 47

CMOS

Front 48

CMOS or CCD uses more power

Back 48

CCD

Front 49

CMOS or CCD - which is more expensive?

Back 49

CCD

Front 50

CMOS or CCD - which tends to have lower quality, resolution, and sensitivity

Back 50

CMOS

Front 51

Pixel fill factor is greater in CCD or CMOS

Back 51

CCD

Front 52

Computer

Back 52

Programmable device that can store, retrieve, and process data

Front 53

Input devices

Back 53

Keyboards, mice, mic, barcode readers, etc

Front 54

Output devices

Back 54

Monitors, printers, speakers, etc

Front 55

Binary code

Back 55

Machine language of 1s and 0s - how computer processes, stores, reads data

Front 56

Bit

Back 56

Single unit of data

Front 57

Byte

Back 57

8 bits

Front 58

Motherboard

Back 58

Largest circuitry board in computer - contains many small components including CPU, BIOS, bus, memory, ports, and CMOS

Front 59

CPU

Back 59

Central processing unit/microprocessor

Small chip on motherboard, acts as brain of computer

Reads data, manipulates it, then sends it back to storage or to external output devices

Front 60

BIOS

Back 60

Basic input/output system - simple set of instructions for computer

Used during boot-up to start computer, runs start-up diagnostics, and after boot-up oversees various functions between OS and hardware

Front 61

Bus

Back 61

Series of connections, controllers and chips that creates "information highway" of the computer

Provides connections for information to flow within the computer

Front 62

RAM

Back 62

Random access memory

Used to store information currently being processed within the CPU

Short-term storage for open programs

Front 63

RAM is temporary or permanent?

Back 63

Temporary - once computer is off, RAM is wiped clean

Front 64

How is memory measured?

Back 64

In bytes - kilobytes, gigabytes, megabytes, etc

Front 65

Ports

Back 65

Connectors, usually in the back of the PC, that link cards, drives, input and output devices, etc

Front 66

CMOS (in the computer)

Back 66

Chip that uses small rechargeable or lithium battery to retain info while PC is turned off

Front 67

Sound card

Back 67

Contains circuitry for recording and reproducing sound

Front 68

Network card

Back 68

Enables PC to connect to other PCs on the same network

Front 69

CRT monitor

Back 69

Cathode ray tube - consists of cathode and anode within a vacuum tube, electrons sent from cathode to anode strike phosphor on monitor glass to produce image

Front 70

LCD monitor

Back 70

Liquid crystal display - produces image by shining light through a layer of liquid crystal and color filters

Front 71

OS

Back 71

Operating system - controls hardware, acts as bridge between applications and hardware

Front 72

Real-time OS

Back 72

Used to control specific machinery, instruments, and industrial systems

Front 73

Single-user, single-task OS

Back 73

Computer can do one task for one person at a time

Front 74

Single-user, multitask OS

Back 74

One user can perform multiple tasks at the same time

Front 75

Multiuser OS

Back 75

Multiple users can perform multiple tasks at the same time

Front 76

Hardware

Back 76

Computer equipment (that can be physically touched)

Front 77

Software

Back 77

Computer programs - set of instructions for computer to perform specific operations

Front 78

Array processor

Back 78

Allows many computer functions to be done at the same time

Front 79

ROM

Back 79

Read only memory

Basic operating instructions that are rarely changed, does not get erased when computer is turned off

Front 80

Network

Back 80

Two or more objects sharing resources and information

or

Computers, terminals, and servers that are connected and share data and resources

Front 81

LAN

Back 81

Local area network - small, close by area networked with cables or wireless access points that allow computers on the network to share information and devices

Front 82

WAN

Back 82

Wide area network - spans a large area (city, state, continent, world) and used to connect computers that aren't physically connected with cables, but instead connected by telephone lines, satellite, etc

Front 83

MAN

Back 83

Metropolitan area network

Front 84

TAN

Back 84

Tiny area network

Front 85

CAN

Back 85

Controller area network

Front 86

Is PACS connected through LAN or WAN?

Back 86

LAN

Front 87

LANs are interconnected to create

Back 87

WAN

Front 88

Peer-to-peer network

Back 88

Each computer on network is considered equal, no computer has control over another

Least expensive, popular for small office

Front 89

Max number of peers on peer-to-peer network

Back 89

10

Front 90

Server-based network

Back 90

A centralized computer (server) controls operations, files, and programs of other computers in the network

Server provides location for centralized storage and retrieval on network

Front 91

PACS is an example of a _____-based network

Back 91

Server

Centralized server contains all the images, images can be sent out to computers on network as requested

Front 92

Client-based network

Back 92

Centralized computer controls operations for network, only sends requested results to client to lessen load on network

Front 93

Server

Back 93

Computer that manages resources for other computers, servers, and networked devices

Front 94

Thin client

Back 94

Device on a network that requests services and resources from a server

Can be any computer, printer, or device that needs the server to complete its tasks

Front 95

Thick client

Back 95

Computer that can work independently of the network and process/manage its own files

Front 96

What purpose might a thick client serve within radiology?

Back 96

Found in sectional imaging modalities to accomodate 3D imaging

Front 97

Communication medium

Back 97

Connection between devices, one of four types

Coaxial cable, twisted-pair wire, fiber optic cable, electromagnetic waves

Front 98

Coaxial cable

Back 98

Consists of center conducting wire surrounded by insulation and a grounded shield of braided wire

Sturdiest wire

Front 99

Twisted-pair wire

Back 99

4 twisted pairs of copper wires, insulated

Front 100

Fiber-optic cable

Back 100

Glass threads instead of wire

Faster, but fragile and expensive

Front 101

Wireless connection

Back 101

Connection made using infrared or radio frequencies to communicate

No physical cabling, but each device must have a transmitter/receiver

Front 102

Network interface card

Back 102

Provides interface between computer and network medium

Front 103

Network hub

Back 103

Simplest device that can be used to connect several pieces of equipment together for network purposes

When data is received, hub sends it to all connected devices

Front 104

Network switch

Back 104

When data is received, network switch sends data only to those devices to which the data is directed (instead of all devices, like a hub)

Reduces network traffic and speeds up communication

Front 105

Network bridge

Back 105

Physical wired connection between network segments

Larger networks can be segmented (broken into smaller networks) and then connected with bridges

Front 106

Network router

Back 106

Reads portions of messages and directs them to intended target, even if the target is on a different network, or uses a different language (protocol)

Front 107

Network topology

Back 107

Physical layout of connected devices on a network - four types: bus, ring, star, mesh

Front 108

Bus topology

Back 108

Network in which all devices are physically attached to a single wire

No switches or hubs

Front 109

Ring topology

Back 109

Network in which devices are connected in a circle, each device passes received data to the next device on the ring until the correct device receives it

Front 110

Star topology

Back 110

Network that has devices connected to a central hub or switch

Most common topology

Front 111

Mesh topology

Back 111

Network that has multiple pathways interconnecting devices and networks

Internet is based on mesh topology, most often used to connect networks to networks

Front 112

DICOM

Back 112

Digital Imaging & Communications in Medicine - universally accepted standard for exchanging medical images among networked medical devices

Front 113

Who developed DICOM and when?

Back 113

Developed by American College of Radiology (ACR) and National Electrical Manufacturers Association (NEMA) in 1985

Front 114

DICOM standard is made up of how many different parts?

Back 114

20

Front 115

SOPs

Back 115

Service/object pair

Front 116

SCU

Back 116

Service class user

-CT scanner

Front 117

SCP

Back 117

Service class provider

-workstation

Front 118

Object class

Back 118

Information about study and patient

Front 119

Service class

Back 119

Describes what to do with objects; storage, image query, image retrieval, image print, etc

Front 120

UIDS

Back 120

Unique identifiers

Globally identify each study, series, and image

Front 121

UIDS are broken down into

Back 121

Study instance UID

Series instance UID

Instance UID

Front 122

Most common compression technology used within DICOM

Back 122

2 to 1 compression

Used because there is no image degradation

Front 123

HL-7

Back 123

ANSI-accredited Standards Developing Organization

Sets standards for medical devices, imaging, insurance, pharmacy

Front 124

HL-7 is used for communication between

Back 124

Hospital information system (HIS) - contains full medical info

and

Radiology information system (RIS) - contains radiology specific patient info

Front 125

EMR is part of

Back 125

HIS

Front 126

EMR

Back 126

Electronic medical record integration

Front 127

Informatics

Back 127

Ideas, devices, processes for handling info

Front 128

BMI

Back 128

Biomedical informatics

Front 129

PACS

Back 129

Picture Archiving and Communications System

Front 130

EHR

Back 130

Electronic healthcare record

Front 131

What is PACS responsible for?

Back 131

Digital image acquisition, distribution, display, and storage

Front 132

PACS communicates via

Back 132

DICOM

Front 133

Archive server

Back 133

"File room" of PACS

Short- and long-term storage

Front 134

Workflow

Back 134

How a process is done step by step

How a radiology exam is completed from order entry to report

Front 135

System architecture

Back 135

Hardware and software infrastructure of a computer system

In PACS, this consists of acquisition devices, storage, display workstations, and an image management system

Front 136

Three common PACS architectures

Back 136

Client/server based systems

Distributed systems

Web-based systems

Front 137

Client/server based system

Back 137

Images are sent directly to archive after acquisition and are centrally located

Tech at display workstation can pull up an image from the server, when finished the image is flushed from the computer memory

Front 138

Advantages of client/server based system

Back 138

All exams sent to PACS are available anywhere

Only one person at a time can open study to read it

Old studies are available with new on the archive

Front 139

Disadvantages of client/server based system

Back 139

Single point failure - if archive goes down, entire system goes down

Network dependent

Can become bottlenecked

Front 140

Distribution/stand-alone systems

Back 140

Images are sent to a designated reading station or review station, usually based on radiologist preference

Workstations can query & retrieve images

Front 141

Advantages of distribution systems

Back 141

If the server is down, local stations can still function

Copies exist at various locations - less likely for data to be lost

Less dependent on network for speed

Front 142

Disadvantages of distribution systems

Back 142

Reliance on assumption that distribution of images is being done correctly

Inconvenient to read additional studies - have to move to another workstation

Possible for two radiologists to be reading same exam, paper requisition is important

Front 143

Web-based system

Back 143

Similar to client/server system except images are searched/viewed in web browser instead of through software

Front 144

Advantages of web-based systems

Back 144

Greater flexibility of hardware, only needs to support web browser instead of specific software

Same application can be used on site and through teleradiology

Front 145

Disadvantages of web-based systems

Back 145

Functionality may be limited because software isn't installed locally, network may limit data transmission

Network dependent

Front 146

Cross-sectional images are read on ___K monitor

Back 146

1K (1280x1024)

Front 147

Digital images are read on ___K monitor

Back 147

2K (1600x1200)

Front 148

Mammography images are read on _____K monitor

Back 148

5K (2048x2560)

Front 149

Who has the highest quality monitors?

Back 149

Radiologists

Front 150

Navigation functions of PACS system

Back 150

Used to move through images, series, studies, and patients

Front 151

Hanging protocols in PACS

Back 151

How a set of images will be displayed on the monitor

Front 152

Study navigation in PACS

Back 152

Navigation through a study - can be a few images (x-ray) to several series (MRI)

Front 153

Stack mode

Back 153

Scrolling through cine images (movie images frame by frame)

Front 154

Image manipulation and enhancement functions

Back 154

Window width/level

Annotations

Flip/rotate

Pan/zoom

Measurements

Front 155

Image management functions

Back 155

Modify pt demographics

Query/retrieve studies

CD burn

Print

Front 156

Advanced workstation functions in the reading station

Back 156

MPR

MIP

VR

SSD

Front 157

Advanced workstation functions for QC technologist station

Back 157

Stitching

Image post-processing; edge enhancement, smoothing, contrast enhancement

Front 158

MPR

Back 158

Multi-planar reconstruction - commonly used 3D rendering technique

Reconstructs data to separate specific body parts

Front 159

MIP

Back 159

Max/min intensity projection (MIP and MinIP)

Used to visualizes vessels and air-filled structures

Front 160

VRT

Back 160

Volume rendering technique - allows user to assign colors based on intensity; bone, contrast, organs all appear in different colors

Front 161

SSD

Back 161

Shaded surface display - removes all intensities below a threshold; everything above the threshold is assigned a color and shown as a 3D object

Front 162

Subtraction

Back 162

Removal of nonessential structures

Bone can be removed to see only tissue and vice versa

Front 163

Image manager

Back 163

Controls receipt, retrieval and distribution of the images it stores

Controls DICOM processes

Front 164

What does the database the image manager runs contain?

Back 164

Only image header, no image data

Front 165

PACS component that interfaces with RIS and HIS

Back 165

Image manager

Front 166

Image storage usually consists of how many tiers

Back 166

2 or 3

Front 167

Short-term tiers can have info available within

Back 167

3 to 5 seconds

Front 168

RAID

Back 168

Redundant array of independent disks

Several disks/hard drives linked together in an array

Front 169

Most common RAID level for PACS

Back 169

RAID 5

Front 170

Why is data striped in RAID levels?

Back 170

Increases reliability and performance

Front 171

How are optical disks created?

Back 171

Photosensitive layer in disk is burned by a light from a laser, creating light and dark spots on the disk

Front 172

Options for long-term storage

Back 172

RAID

Jukebox

Optical disks (MOD, DVD, UDO)

Tape (LTO, DLT)

Front 173

MOD

Back 173

Magneto-optical disk

Similar to CD & DVD in that its read optically with a laser, but it is housed in a plastic cartridge

Reliable and sturdy

Front 174

Three ways magnetic disks can be stored

Back 174

DAS - direct attached storage

NAS - network attached storage

SAN - storage area network

Front 175

Which magnetic disk storage is most popular in healthcare?

Back 175

SAN - connects all modalities

Front 176

ASP

Back 176

Application service provider

Outsourcing of archiving and management functions

Short term archive located on hospital premises

Long term must be located off site

Front 177

Film digitizer

Back 177

Scans analog image to produce digital image

Front 178

What type of beam is used in a laser film digitizer?

Back 178

Helium neon laser beam

Front 179

Infrared (nm)

Back 179

780-820 nm

Front 180

Helium neon (nm)

Back 180

633 nm

Front 181

Components of a laser printer

Back 181

Laser source

Collimator or beam shaping optics

Beam modulator

Deflecting mirror-shaping lenses

Cylindrical reflection mirror

Front 182

What direction are CDs burned?

Back 182

From center to outside

Front 183

Formula for image file size

Back 183

XY (B/8 bits)

Front 184

Size of image file is dependent on what two things?

Back 184

Matrix size and bit depth

Front 185

Grayscale bit depth ranges from

Back 185

8 to 32 bits

Front 186

Quality assurance (QA)

Back 186

Plan for observation and assessment of a project/service/facility to make sure standards of quality are being met

Focused on people and service

Front 187

Quality control

Back 187

Set of activities to monitor and maintain systems that produce a product

-making sure x-rays are performed safely, all parts working prperly

Front 188

Continuous quality improvement (CQI)

Back 188

Focuses on process rather than people or service

If process is good, people will follow, and service will be good

Front 189

Acceptance testing

Back 189

Testing done by manufacturer with newly installed or majorly repaired equipment

Front 190

Routine maintenance

Back 190

to verify equipment is performing as expected

Front 191

Error maintenance

Back 191

Corrective action after poor quality performance

Front 192

ACR suggests quality tests should be carried out with

Back 192

SMPTE test pattern

Society of Motion Pictures and Television Engineers

Front 193

Back 193

SMPTE test pattern

Front 194

Back 194

TG18 test pattern

Front 195

What does monitor testing look for?

Back 195

Artifacts

Geometric distortion

Luminance

Reflection

Noise

Glare

Resolution

Front 196

Recognition of nondiagnostic images

Back 196

Monitoring how many poor-quality images are sent to radiologists - why they are poor quality

Front 197

System up-time

Back 197

Monitoring how often system is down for any reason and why

Front 198

System training

Back 198

Vendor stays onsite for 1-2 weeks

Superusers train all other techs