EXAM #5 Flashcards

Question 1

Q

[What is fluoroscopy]

_____ time viewing of anatomical structures

_____ picture x-ray, can stop and take static images,

Most of it IS/IS NOT captured

DOES/DOES NOT have the spatial resolution as normal x-ray (static image)

Answer

A

[What is fluoroscopy]

Real time viewing of anatomical structures

Motion picture x-ray, can stop and take static images,

Most of it IS NOT captured

DOES NOT have the spatial resolution as normal x-ray (static image)

Question 2

Q

3 Components of fluoroscopy

Answer

A

Image intensifier

TV

CRT tube

Question 3

Q

[Fluoroscopy]

Is flouro dynamic?

Answer

A

[Fluoroscopy]

YES

Question 4

Q

[Fluoroscopy]

Discovered in _____ by _____

Answer

A

[Fluoroscopy]

Discovered in 1896 by Edison

Question 5

Q

[Fluoroscopy]

Continuous energizing of x-ray tube is needed

Answer

A

[Fluoroscopy]

Continuous energizing of x-ray tube is needed

Question 6

Q

[Fluoroscopy]

What is something we can do to reduce heat in fluoroscopy

Answer

A

[Fluoroscopy]

Drop mAs

Question 7

Q

[Fluoroscopy]

Low mAs in fluoro = _____ images

Answer

A

[Fluoroscopy]

Low mAs in fluoro = noisy images

Question 8

Q

[Fluoroscopy]

DA stands for…

DSA stands for…

Answer

A

[Fluoroscopy]

Digital Angiography

Digital Subtraction Angiography (subtracts anatomy we don’t want to look at)

Question 9

Q

[Fluoroscopy]

Where is the tube for fluoroscopy? Except for?

Where should shielding be?

Answer

A

[Fluoroscopy]

Tube is in the table (w/ Bucky), except for remote rooms

Shielding should be between the pt and the table

Question 10

Q

[Fluoroscopy]

What exams do not get a curtain

Answer

A

[Fluoroscopy]

Anything that is a sterile field does not get the curtain

Question 11

Q

[Fluoroscopy]

What happens when the Bucky slot cover is broken off?

Answer

A

[Fluoroscopy]

Leakage from tube

Question 12

Q

[Fluoroscopic Technical Factors ]

Common mAs?

Warning bell purpose?

Answer

A

[Fluoroscopic Technical Factors]

1 - 5 mAs

5 minute warning bell to let practitioner know because most cases should be done in less time than that

Question 13

Q

[Fluoroscopic Technical Factors]

Patient dose is considerably high/low

_____, is selected for body type being imaged (chest, belly) and what _____ material we’re using

Answer

A

[Fluoroscopic Technical Factors]

Patient dose is considerably high

kVp, is selected for body type being imaged (chest, belly) and what contrast material we’re using

Question 14

Q

[Fluoroscopic Technical Factors]

If we’re using iodine, and I’m looking at vessels or kidneys we want to be around __kVp

If I’m looking at your GI tract, we have to be above kVp

Has to do with z number and k-edge, the average is about 35 and the k-edge is 33

pick ___ to match the contrast

Answer

A

[Fluoroscopic Technical Factors]

If we’re using iodine, and I’m looking at vessels or kidneys we want to be around 70KeV

If I’m looking at your GI tract, we have to be above 100KeV

Has to do with z number and k-edge, the average is about 35 and the k-edge is 33

pick kVp to match the contrast

Question 15

Q

[Fluoroscopic Technical Factors]

Image Brightness level is selected, and factors (mAs & kVp) are adjusted automatically to meet the required brightness level know as _____.

The advantage of ABC over AEC?

Disadvantage?

Answer

A

[Fluoroscopic Technical Factors]

Image Brightness level is selected, and factors (mAs & kVp) are adjusted automatically to meet the required brightness level know as ABC.

It’s advantage is that it will adjust the KV and the mA (the quality and quantity) while AEC only adjusts mA

It’s disadvantage is that it’s about a second behind (delayed)

Question 16

Q

[How do we provide a moving image? ]

Image intensification is necessary to provide _____ images.

Illumination is measured in _____ (L) and _____ (mL).

Answer

A

[How do we provide a moving image?]

Image intensification is necessary to provide quality images.

Illumination is measured in Lambert (L) and mililambers (mL).

Question 17

Q

[How do we provide a moving image?]

An aperture is used to control the _____ between the image intensifier and the television camera tube.

Answer

A

[How do we provide a moving image?]

An aperture is used to control the light between the image intensifier and the television camera tube.

Question 18

Q

[How do we provide a moving image?]

Human eyes use _____ and _____ to perceive light levels.

_____ - sensitive to low light 10-6 mL, night or scotopic, not good at seeing detail

_____ sensitive to bright light 10-2 mL, daylight or photopic, better at seeing detail

Answer

A

[How do we provide a moving image?]

Human eyes use rods and cones to perceive light levels.

Rod- sensitive to low light 10-6 mL, night or scotopic

Cones sensitive to bright light 10-2 mL, daylight or photopic

Question 19

Q

[How do we provide a moving image?]

With out intensification, _____ vision was used, requiring time to adjust to darkness.

Brightness increase allow for sight with _____ vision, faster and better (higher detail with cone vision).

mAs, kVp, and the anatomy control _____

Answer

A

[How do we provide a moving image?]

With out intensification, rod vision was used, requiring time to adjust to darkness.

Brightness increase allow for sight with cone vision, faster and better (higher detail with cone vision).

mAs, kVp, and the anatomy control brightness

Question 20

Q

[Brightness- why is it so important? ]

With out intensification, rod vision was used, requiring time to adjust to darkness.

Brightness increase allow for sight with cone vision, faster and better (higher detail with cone vision).

mAs, kVp, and the anatomy control brightness

Answer

A

[Brightness- why is it so important?]

With out intensification, rod vision was used, requiring time to adjust to darkness.

Brightness increase allow for sight with cone vision, faster and better (higher detail with cone vision).

mAs, kVp, and the anatomy control brightness

Question 21

Q

[Image Intensifier ]

Converts image forming x-rays into _____ photons of high _____.

The components to do this are housed in an envelope, creating a _____.

X-rays interact with phosphors (_____) creating light.

SCINTILLATOR the very first layer of this is made of _____ _____

Similar to the process seen with radiographic scintillators, however, CsI phosphors are designed to have little divergence and higher spatial resolution.

Answer

A

[Image Intensifier ]

Converts image forming x-rays into light photons of high intensity.

The components to do this are housed in an envelope, creating a vacuum.

X-rays interact with phosphors (CsI) creating light.

SCINTILLATOR the very first layer of this is made of cesium iodine

Similar to the process seen with radiographic scintillators, however, CsI phosphors are designed to have little divergence and higher spatial resolution.

Question 22

Q

The photocathode is adjacent to the intensifier and made of metal. The light emitted by the _____ (material) causes electrons to be emitted by the photocathode.

The number of electrons emitted is _____ proportional to the intensity of the light (which is proportional to the incident x-ray); however, many light photons are needed to emit one electron.

Starts out dim and spread out, shrunk down and sped up to be focused at anode (made of _____ _____) to be made brighter at the output phosphor

Answer

A

The photocathode is adjacent to the intensifier and made of metal. The light emitted by the CsI (material) causes electrons to be emitted by the photocathode.

The number of electrons emitted is directly proportional to the intensity of the light (which is proportional to the incident x-ray); however, many light photons are needed to emit one electron.

Starts out dim and spread out, shrunk down and sped up to be focused at anode (made of zinc cadmium sulfate) to be made brighter

Question 23

Q

A potential of 25 kV is maintained across the vacuum, so the electrons will travel to the opposite end or the anode. This anode has a small hole, where the electrons pass through to the _____ _____.

Answer

A

A potential of 25 kV is maintained across the vacuum, so the electrons will travel to the opposite end or the anode. This anode has a small hole, where the electrons pass through to the output phosphor.

Question 24

Q

The output phosphor then converts the electrons back to _____ _____.

Answer

A

The output phosphor then converts the electrons back to light photons.

Question 25

Q

Electrostatic focusing lenses are used to _____ the electron beam while maintaining its _____. The electrons have high velocity and are minified at the _____ _____.

Answer

A

Electrostatic focusing lenses are used to focus the electron beam while maintaining its integrity. The electrons have high velocity and are minified at the output phosphor.

Question 26

Q

The intensification is realized at this point where every electron creates __-__ times more light than it took to create it.

Answer

A

The intensification is realized at this point where every electron creates 50-75 times more light than it took to create it.

Question 27

Q

Flux gain is used to describe the ______ _____ at _____ compared to the number of incident x-rays.

Answer

A

Flux gain is used to describe the light photons at output compared to the number of incident x-rays.

Question 28

Q

Brightness gain is used to describe the intensifiers ability to _____ _____. Usually _____-_____.

Answer

A

Brightness gain is used to describe the intensifiers ability to increase illumination. Usually 5,000-30,000.

Question 29

Q

Minification gain is used to describe the _____ in _____ of _____ phosphor verses _____ phosphor.

Minification gain = Big dull image and I squished you down into a small intense image

Answer

A

Minification gain is used to describe the difference in size of output phosphor verses input phosphor.

Minification gain = Big dull image and I squished you down into a small intense image

Question 30

Q

What is convergence factor?

Its usual range?

Answer

A

Convergence factor - ratio of the illumination intensity at output to the radiation incident on input phosphor.

Usually 50-300.

Question 31

Q

Dualfield input phosphor size __ - __

Trifield input phosphor size __ - __ - __

Answer

A

Dualfield input phosphor size 25-17

Trifield input phosphor size 25-17-12

Question 32

Q

_____ and _____ = total brightness gain

Answer

A

FLUX and MINIFICATION = total brightness gain

Question 33

Q

Between _____ and _____ there is a screen (filter) that allows photons go through without coming back

Answer

A

Between ANODE and PHOSPHOR there is a screen (filter) that allows photons go through without coming back

Question 34

Q

Multi-field Image Intensification is also known as…

Question 35

Q

The electrostatic lenses charge is increased when a SMALLER/LARGER input phosphor is used. Resulting in a SMALLER/LARGER electron beam at the output phosphor. The focal point is also moved CLOSER/FARTHER from the output phosphor.

Answer

A

The electrostatic lenses charge is increased when a SMALLER input phosphor is used. Resulting in a SMALLER electron beam at the output phosphor. The focal point is also moved FARTHER from the output phosphor.

Question 36

Q

If a curved input phosphor wasn’t used, the image would be _____

Answer

A

If a curved input phosphor wasn’t used, the image would be DISTORTED

Question 37

Q

Electronic collimation = _____ _____, two important things happen

1 - The area irradiated INCREASES/DECREASES, and INCREASES/DECREASES FoV

2 - Focusing lenses need to change their _____ to narrow the beam to not shrink down as much and image appears BIGGER/SMALLER

MORE/LESS technique?

MORE/LESS ESE?

MORE/LESS pt. dose? Why?

Answer

A

Electronic collimation = MAG MODE, two important things happen

1 - The area irradiated DECREASES, and DESCREASES FoV

2 - Focusing lenses need to change their CHARGE to narrow the beam to not shrink down as much and image appears BIGGER

MORE technique

MORE PT ENTRANCE SKIN EXPOSURE

SAME pt. dose because more technique, less FoV

Question 38

Q

The output phosphor must be connected to a viewing devise. Most commonly a _____ _____ _____. _____.

_____ and same size as output phosphor.

Answer

A

The output phosphor must be connected to a viewing devise. Most commonly a TV CAMERA TUBE. VIDICON.

SENSITIVE and same size as output phosphor.

Question 39

Q

The TV camera takes the _____ from output phosphor and converts it to an electrical _____ to be reconstructed as a TV image.

Answer

A

The TV camera takes the light from output phosphor and converts it to an electrical signal to be reconstructed as a TV image.

Question 40

Q

TV monitors can have _____ and _____ adjusters, which is an advantage.

Exams can also be stored _____.

Answer

A

TV monitors can have BRIGHTNESS and CONTRAST adjusters, which is an advantage.

Exams can also be stored electronically.

Question 41

Q

[Vidicon]

Components are housed in an envelope that creates a _____.

Electrons are released from the electron gun and a beam is constructed by the _____/_____ grids.

Answer

A

[Vidicon]

Components are housed in an envelope that creates a vacuum.

Electrons are released from the electron gun and a beam is constructed by the control/acceleration grids.

Question 42

Q

[Vidicon]

External electromagnetic coils _____ and _____ the beam.

At the anode the beam interacts with a _____ layered target.

The signal plate conducts electricity to the _____/_____ layer and produces an image by emitting _____.

Answer

A

[Vidicon]

External electromagnetic coils focus and direct the beam.

At the anode the beam interacts with a three layered target.

The signal plate conducts electricity to the target/photoconductive layer and produces an image by emitting light.

Question 43

Q

[Fiber optics]

Advantage?

Disadvantage?

Answer

A

[Fiber optics]

Advantage small, compact easy to move tower, sturdy

Disadvantage- no additional imaging devices, only spot film can be used.

Question 44

Q

[Lenses]

If _____ or _____ (reel of film) is used lens coupling is required. Careful handling is required.

Object lens converts output phosphor light into two _____ beams. This beam interrupted by beam splitting _____. A portion goes to the spot film and the other to the Vidicon.

Answer

A

[Lenses ]

If spot or cine (reel of film) is used lens coupling is required. Careful handling is required.

Object lens converts output phosphor light into two parallel beams. This beam interrupted by beam splitting mirror. A portion goes to the spot film and the other to the Vidicon.

(Beam splitting mirrors are movable and in place only when needed.)

Question 45

Q

[Lenses]

The parallel light beams are then _____ by lenses from the respective devices, camera or spot film. The lens alignment is critical in point for image quality.

Answer

A

[Lenses]

The parallel light beams are then focused by lenses from the respective devices, camera or spot film. The lens alignment is critical in point for image quality.

Question 46

Q

With photospots, doses are HIGHER/LOWER

Question 47

Q

[Television Monitor]

The signal is _____ and transmitted by cable to the monitor, where a visible image is made.

The TV monitor and camera are the two ends of a _____ circuit system

The TV Monitor is essentially a _____ ray tube. It is very similar to the TV camera tube; however, it is larger and its anode is a _____ screen with a graphite lining.

Answer

A

[Television Monitor]

The signal is amplified and transmitted by cable to the monitor, where a visible image is made.

The TV monitor and camera are the two ends of a closed circuit system

The TV Monitor is essentially a cathode ray tube. It is very similar to the TV camera tube; however, it is larger and its anode is a florescent screen with a graphite lining.

Question 48

Q

[Television Monitor]

The input signal can be amplified and is proportional to the light intensity received by the TV camera.

The modulation is controlled by the _____ _____.

This _____ and the _____ _____ focus the electron beam onto the output phosphor, to produce a burst of _____.

Answer

A

[Television Monitor]

The input signal can be amplified and is proportional to the light intensity received by the TV camera.

The modulation is controlled by the control grid.

This grid and the external coil focus the electron beam onto the output phosphor, to produce a burst of light.

Question 49

Q

[The Image]

As the electron beams, TV camera and TV tube, move in synchronous timing to create an image the electromagnetic coil direct its pattern

This pattern is known as a _____ pattern.

This pattern starts at the _____ _____ part of the screen an works in a diagonal fashion down the screen.

Answer

A

[The Image]

As the electron beams, TV camera and TV tube, move in synchronous timing to create an image the electromagnetic coil direct its pattern

This pattern is known as a Raster pattern.

This pattern starts at the upper left part of the screen an works in a diagonal fashion down the screen.

Question 50

Q

[The Image]

Again, the pattern starts at the _____ of the screen and works its way _____, although , the second pattern is worked in _____ the lines of the first.

This is known as _____, two of these fields create one TV _____.

The _____ lines are one field, the _____ lines are one field, and they make up together an entire _____

Answer

A

[The Image]

Again, the pattern starts at the top of the screen and works its way down, although , the second pattern is worked in between the lines of the first.

This is known as interlacing, two of these fields create one TV frame.

The odd lines are one field, the even lines are one field, and they make up together an entire frame

Question 51

Q

Fields and frames per second for digital progressive and traditional interlaced?

Answer

A

Digital progressive:
fields = 1/30 sec

frames = 1/30 sec

Traditional interlaced:
fields = 1/60 or 2/30 sec
frames = 1/30 sec

Question 52

Q

As the TV signal is created, it immediately starts to fade, each new TV frame represents __ ms of new information.

___ line systems- ___ lines of active trace per frame ___ are available for hi resolution images

Answer

A

As the TV signal is created, it immediately starts to fade, each new TV frame represents 33 ms of new information.

525 line systems- 525 lines of active trace per frame 1024 are available for hi resolution images

Question 53

Q

What controls quality of the picture?

1 - vertical resolution (how many _____ in system) more _____ = closer together = BETTER/WORSE resolution

2 - horizontal resolution (_____) = how many times can I change the _____ _____ as I’m crossing the field. The more I can change it, the more specific I can be to represent an object

The ideal monitor has _____ vertical and horizontal resolution.

Answer

A

What controls quality of the picture?

1 - vertical resolution (how many lines in system) more lines = closer together = BETTER resolution

2 - horizontal resolution (bandpass) = how many times can I change the electron gun as I’m crossing the field. The more I can change it, the more specific I can be to represent an object

The ideal monitor has equal vertical and horizontal resolution.

Question 54

Q

Monitors display __ lp/mm, intensifiers display __ lp/mm. The monitor is the weakest link in the _____ chain.

Images are taken during Fluoroscopy to take advantage of the intensifiers superior _____.

Answer

A

Monitors display 2 lp/mm, intensifiers display 5 lp/mm. The monitor is the weakest link in the resolution chain.

Images are taken during Fluoroscopy to take advantage of the intensifiers superior resolution.

Question 55

Q

[How do we take images during Fluoroscopy? ]

Spot film cameras- Places receptor between _____ and _____. The receptor is removed from it’s lead housing and exposed using a HIGH/LOW mAs radiographic technique.

These mechanical alterations may take __-__ sec.

Answer

A

[How do we take images during Fluoroscopy?]

Spot film cameras- Places receptor between Patient and intensifier. The receptor is removed from it’s lead housing and exposed using a HIGH mAs radiographic technique.

These mechanical alterations may take 1-2 sec.

Question 56

Q

[How do we take images during Fluoroscopy?]

Several types of film use patterns are available. 1 on 1, 2,3,4, on one.

Quality images are produced however, dose is LOWER/HIGHER and time is a factor.

Answer

A

[How do we take images during Fluoroscopy?]

Several types of film use patterns are available. 1 on 1, 2,3,4, on one.

Quality images are produced however, dose is HIGHER and time is a factor.

Question 57

Q

Photospot camera - exposes one frame of film per x-ray exposure.

Image is derived form intensifier, using the beam splitting mirror therefor, less dose is needed. (BETTER/WORSE)

_____ time is required to take image.

70 and 105 mm film are used, _____ film generates better images.

Answer

A

Photospot camera - exposes one frame of film per x-ray exposure.

Image is derived form intensifier, using the beam splitting mirror therefor, less dose is needed. (BETTER)

Minimal time is required to take image.

70 and 105 mm film are used, larger film generates better images.

Question 58

Q

[Digital Fluoroscopy]

The x-ray tube is _____, so that multiple static images are obtained. 1-__ per second (fields, common 4, 7, 15).
_____ time is the measure of time it takes the tube to be turned on.

Answer

A

[Digital Fluoroscopy]

The x-ray tube is pulsed, so that multiple static images are obtained. 1-60 per second (fields, common 4, 7, 15).
Interrogation time is the measure of time it takes the tube to be turned on.

(we no longer use continuous fluoro, the x-ray tube is going to pulse)

Question 59

Q

[Digital Fluoroscopy]

_____ mode reading of the camera tube is necessary.

One entire field is transmitted in __ms. The signal to noise ratio is also very _____ (___:1) – providing _____ image quality.

When do we use it?

Answer

A

[Digital Fluoroscopy]

Progressive mode reading of the camera tube is necessary.

One entire field is transmitted in 33ms. The signal to noise ratio is also very HIGH (1000:1) – providing HIGH image quality.

We use progressive mode during digital fluoro.

Question 60

Q

1) The TV camera tube transmits the analog signal to the _____ to _____ Converter, where it is put in digital form. _____ then transfers information to memory for storage.
2) A CCD (charged coupled device) can be connected via _____, acquires the image and sends to the computer as a digital signal.
3) A FPIR (flat panel image receptor) can be used with out an _____.

Answer

A

1) The TV camera tube transmits the analog signal to the Analog to Digital Converter, where it is put in digital form. ADC then transfers information to memory for storage.
2) A CCD can be connected via optics, acquires the image and sends to the computer as a digital signal.
3) A FPIR (flat panel image receptor) can be used with out an II.

Question 61

Q

Image subtraction accomplished with digital images.

An _____ beam is needed for subtraction imaging

Two types are available:
• _____ subtraction
• _____ subtraction

Answer

A

Image subtraction accomplished with digital images.

An area beam is needed for subtraction imaging

Two types are available:
• Temporal subtraction
• Energy subtraction

Question 62

Q

1) Temporal subtraction
an image obtained at the _____ is subtracted from further images.

Mask mode- mask is taken _____ to injection, this image is subtracted from all subsequent images.
Time interval difference mode- each subtracted image is made with a different mask. Often set __-__ frames apart.

_____ is possible with each of these modes

2) Energy subtraction
two energy x-ray beams are used at pulsating _____. Different energies can be created or a metal filter can be used to accomplish.

Answer

A

1) Temporal subtraction
an image obtained at the start is subtracted from further images.

Mask mode- mask is taken prior to injection, this image is subtracted from all subsequent images.
Time interval difference mode- each subtracted image is made with a different mask. Often set 2-4 frames apart.

Misregistration is possible with each of these modes

2) Energy subtraction
two energy x-ray beams are used at pulsating times. Different energies can be created or a metal filter can be used to accomplish.

Question 63

Q

ABC = ABS

Answer

A

ABC = ABS

Question 64

Q

AGC

Electronic _____ of _____, not the amount of _____ going into the system

Noisy = not enough _____

Answer

A

AGC = Automatic Gain Control

Electronic amplification of signal, not the amount of radiation going into the system

Noisy = not enough signal

EXAMPLE: heavy person, upped to the max kV and mAs, ABC still doesn’t get what it wants so AGC amplifies it

Answer 63

A

pixel shift = shifting mask over by pixels in temporal subtraction

Answer 64

A

everyone can read an image at the same time

Answer 65

A

[PACS]

A networked group of computers, servers, and archives that can be used to manage digital images.

A PACS serves as file room, reading room, duplicator and courier.

All images must be in DICOM format, for communication among computers and storage. (all of the image information, RAW data which can communicate between different branded units) kV, mA, and time (exposure index, REX) header (info) and image are separate

Answer 66

A

[HL-7]

Standard oversees most clinical and administrative data such a demographics, reports, claims and orders.

Used to communicate between Hospital Information system (HIS) and Radiology Information System (RIS) and EMR (Electronic Medical Record).

HL-7 interfaces with DICOM for error free data flow.

Answer 67

A

[The Computer]

Basically there are input, output and processing devices.

Information is a series of 0s and 1s known as binary code.

Bit, a 1 or a 0, indicates flow of current

Byte- is 8 bits strung together

One byte usually represents an alphanumeric character.

1 million bytes are a Megabyte (MB)
1 billion bytes are a Gigabyte (GB)

Answer 68

A

Motherboard - where all components are CONNECTED

Central Processing Unit (CPU) - where all calculations happen (controls SPEED)

OTher three components:
• Bus
• Ports
• CMOS (Complimentary Metal Oxide Semiconductor)

Answer 69

A

[Central Processing Unit]

Is a small computer chip on the motherboard.

The CPU functions to read data from storage, manipulate or process data, and then move it to storage or send for printing or to external devices.

Two main manufacturers, Intel and AMD

Discussion generally is about speed, modern CPUs are at 3.2 -3.8 GHz.

Answer 70

A

array and micro processors

microprocessor = bus system, one packet of information calculated and sent out (pipeline system)

array = multiple problems at the same time, fast

Answer 71

A

[BIOS]

Simple set of instructions for the computer

Used during boot up, ensures all peripheral devices are working properly

Intermediary Operating system and hardware

Answer 72

A

[BUS]

A series of connections, controllers, and chips that create the information highway of the computer.

There are several highways within one computer

Allows connection for data exchange, most common is the universal serial bus or USB

Answer 73

A

[CMOS]

Complimentary metal oxide semiconductor

Small chips powered by batteries that maintain some memory while computer is turned off. (time and date)

Answer 74

A

[Network Card]

Allows one PC to connect to a network for communication with other computers.

Answer 75

A

[Hard drive]

Main storage for programs and files on a PC

Composed of many hard, thin, magnetic platters that are stacked with only enough room between for a read/write head to perform tasks

Modern computers can hold ~100GB of information and access it at rates of ~9msec

Answer 76

A

[CD/DVD NOT GOOD FOR LONG TIME STORAGE]
Both of these can be read only memory (ROM), write once read many (R), or read and write many (WR).

CD
A plastic disk, with bumps molded in to it representing 0s or 1s of data.
Can hold upwards of 650MB of data, or ~75 minutes of music

DVD
Capacity is 7 times that of CD, ~10/20 GB, single or double sided.

Answer 77

A

[Operating Systems]

Software that controls hardware, acts as a bridge between applications and hardware.

Three major vendors in modern computers:

Widows
Macintosh
UNIX/Linux- best available, least likely to incur problems

Answer 78

A

Local Area Network- LAN

Small area networked through cable, faster, cover small area, allow many users to share data.

Several LANs can be networked to form a WAN

Answer 79

A

Wide Area Network –WAN

Large area networked, often through wireless, slower due to area. Allows the most number of users access.

PACS is generally part of a WAN.

Answer 80

A

Teleradiology/telemedicine = doing stuff over a distance (Radiologists at home through VPN)

Answer 81

A

[Server]

Manages resources of other computers, servers are networked devices

House programs, provide storage, has limited tasks

Generally the most robust computer in network

Thin Client- requests services from server (PC)

Thick Client- capable of managing its own data and processing it, on network to share security and use peripherals, like printers. (3D workstation in CT)

Answer 82

A

Bus
• All computers are attached by single wire. Single point of failure.

Star
• All devices are connected to a central hub. All data passes through hub. Commonly used
• May be slow due to data congestion at one point

Mesh
• Multiple pathways interconnecting PCs and networks- the internet!

Answer 83

A

Image Acquisition
• CT,MR, CR or Digital Room

Display Workstation
• Technologist workstation
• Radiologist reading station

Archive Servers
• File room of PACS
• Database server, short term and long term storage, workflow manager computer.

Answer 84

A

[Client/Server Based PACS System]

Images are sent to archive server after acquisition

Pulling up images from a list is actually asking the server to send a copy of the images to the client, the PC.

Once images are no longer needed they are deleted from the PCs memory

Answer 85

A

[Client/Server Based PACS System]

Advantages:
• Exam available thru PACS
• Only one person can read it
• Old/new studies are available

Disadvantages:
• Single point of failure- archive server
• Network dependent- can slow speed
• Archive dependent- can slow speed

Answer 86

A

[Distributed PACS System]

Images are sent to read/viewing station

Images may be sent to archive also, system dependent

Once read they are sent for permanent storage

All images stay on PC hard drive, until deleted

Answer 87

A

[Distributed System]

Advantages:
• Not archive dependent
• Multiple data copies- less loss
• Not Network dependent- increase speed

Disadvantages:
• Incorrect distribution – no old exam
• Work list is PC limited- can slow reading speed
• Non scheduled exams- might not have data

Answer 88

A

[Web Based System]

Same data flow as Client server.

Both images and display software are held at server.

Answer 89

A

[Web Based System]

Advantages:
• Flexibility in hardware
• Software can be used by all

Disadvantages:
• Not all hardware is at diagnostic quality
• Large software may limit of slow system
• Network dependent

Answer 90

A

[Archiving Components]

The archive is a complex arrangement of computers and storage space.

This consists of hardware and software
• Image managers/controllers
• Image storage /servers

Archives store all image data often on magnetic tape or optical disks.

Answer 91

A

[Archiving Components]

Image Mangers:

Master database of everything in archive.

Controls receipt, retrieval and distribution of images

Database contains only the header information, no image data.

This component is mirrored for seamless processing, if one fails, backup kicks in

Manager communicates with RIS and HIS

Answer 92

A

[Archive server]

This is the physical storage area, consists of layers

Short term:
RAID, magnetic disks or hard drives in an array

200Gb to 1 Tb

As data enters the RAID, it is broken into packets and stored separately.

Some redundancy, good for loss prevention

Also faster for retrieval

Answer 93

A

[Long term]

Application Service Providers (ASP)-
• Outsourcing of archiving and management functions on a pay per click or pay per month charge.
• Disaster recovery or off site data storage, as in another state. Would update every night at 12 act, so it would not be fully complete, but very close.

Answer 94

A

[Long term]

Magnetic-optical disk-MOD- similar to a DVD or CD, but disk is housed in a plastic cassette, they withstand reading very well over time, holds 9.1 Gb

DVD- least expensive form of storage, holds 17Gb

Answer 95

A

[Long term]

Tape- able to archive the most data, hundreds of Tb

Tapes are housed in a jukebox for playing

Tapes can wear and break, a disadvantage
400 Gb/tape linear open tape
300 Gb/tape Digital linear tape
200Gb-2 TB/ tape Advanced intelligence tape

Answer 96

A

[Display Stations]

PC, 2 monitors, mouse and keyboard

Monitors can be a CRT or LCD

LCD are most common:

Increased resolution

Lack of heat/x-ray production

Decreased maintenance

Can be used with moderate ambient light

Answer 97

A

[Display resolution]

CT and MR
Require a 1 K square monitor, or a 1280 X 1024

Radiology
Require a 2 K square monitor, or a 1600 X 1200

Mammography
Require a 5 K square monitor, or a 2048 X 2056

Answer 98

A

[Workstations]

Reading:

Must be of highest quality

Access to RIS, HIS and dictation are needed.

Answer 99

A

[Workstations]

Viewing:

Step down model of reading station.

Reports are available with images for referring physicians, limited manipulation of image

Answer 100

A

[Workstations]

Technologist QC:

Lowest quality, can access old exams when needed.

Answer 101

A

PIXEL SIZE = FoV / MATRIX

Answer 102

A

the amount of grays that can be displayed

More grayscale = MORE shades of gray

Answer 103

A

CT and MR

Answer 104

A

[Image Characteristics]

Matrix- combination of rows and columns. Each cell represents a brightness for that location.

Pixel- each cell in an image, AKA picture element. The value of this cell determines brightness and is related to attenuation of tissue imaged. In CT it is a Houndsfield Unit. RESOLUTION can never be better than size of pixel.

Answer 105

A

In CR, we are always going to choose the smallest IR that will fit the part

Because it’s going to give us the smallest pixel and best spatial resolution

Answer 106

A

[Image Characteristics]

FOV- field of view, area for display of image, 2000 X 2000 for diagnostics, 4000 x 3000 for mammography (size of IR)

Pixel size = FOV/matrix

Answer 107

A

Dynamic range is the numerical range of each pixel, what it can show

Eyes perceive 32 shades of gray(25), 65536 (216) can be displayed; however we cannot appreciate them.

Answer 108

A

[Dynamic Range]

Windowing- post processing done to limit range of gray scale visualized.

Level- selected as midpoint of image, selected to show tissue being imaged. Controls BRIGHTNESS
Width- range around level that is included in image. Controls CONTRAST

The wider the width, the LARGER the exposure latitude, the grayer the image

Answer 109

A

NARROW window width to see soft tissues

Answer 110

A

With increased subject contrast, WIDE window width

With decreased subject contrast, NARROW window width

Answer 111

A

[Computed Radiography]

uses cassettes filed with a reusable photo-stimulable phosphor plate

Answer 112

A

The order in which images are taken and displayed to the radiologist

Answer 113

A

CR cassettes are highly sensitive to scatter and fog; therefore, they must be processed once a day to prevent excessive fog

Answer 114

A

Latent images will degrade over time, ~ 25% in 8 hr.

Answer 115

A

Barium fluorohalide bromides BaFBr:Eu or BaFI:Eu and iodide

Answer 116

A

Needle PSP (CsI)

Answer 117

A

[Workstation and Monitors]

When reading a plate the Technologist must load demographic information, such as name, DOB & X-ray #

This is often done with a bar code/worklist from the RIS that will automatically load data.

Answer 118

A

[Workstation and Monitors]

The technologist must also select the exam and view to be processed for each plate.

Selecting the view will select the histogram, Look Up Table and algorithm for processing the plate.

Answer 119

A

[Workstation and Monitors]

The histogram is specific to the part, if the selected part and that which is run differ, the image will be of poor quality.

Generally CR has a linear H & D curve this can be “tweaked” for optimal viewing of data and technical flexibility (LUT)

Answer 120

A

VoI = values of interest

I don’t care about part that was collimated, it’s not an area of interest

I don’t care about the raw radiation either

Answer 121

A

[Algorithms]

High frequency algorithm = small objects/detail

Edge enhancing algorithm = increases edge of bone

Low frequency algorithm = decreases noise and improves contrast

Answer 122

A

high frequency algorithm to improve detail of soft tissue

Answer 123

A

Lookup table takes very gray image and adjusts brightness and contrast

Answer 124

A

Due to the linear nature of the H & D curve the system can compensate for overexposure of 80% and underexposures of 20%

Answer 125

A

Over exposures result in loss of contrast, due to detector saturation.

Answer 126

A

Underexposure results in excessive noise .

Answer 127

A

The image that appears on the workstation is for initial viewing only, do not change Window or use edge enhancement if sending to PACS- image maybe locked and the Radiologist will not be able to post process!!

Answer 128

A

Dia positive- Fuji, Cronex:

Overexposure appears white/bright

Underexposure appears black/dark

Take only one projection per cassette- reader covers whole plate at one time

Answer 129

A

Positive- Kodak, Agfa:

Similar to film screen, white is under and black is over exposed

More than one projection per cassette is possible, not recommended- reader covers plate in areas or blocks

Answer 130

A

Fuji systems’ method of locating the raw data

• Automatic:
Adjusts the latitude and sensitivity for the image
Used when collimation is parallel/equidistant and the central ray and part are centered

• Semiautomatic:
Adjusts the sensitivity, but not the latitude
Can be used when collimation is not parallel/equidistant

• Fixed- film like:
Does not adjust sensitivity or latitude
Requires use of proper technical factors

Answer 131

A

yes, because less repeats only

Answer 132

A

[Collimation]

Must be even on both sides

Centering is imperative

Must go back to proper positioning protocols (must use lead markers)

No more combining of exams

Always use the smallest cassette possible

Answer 133

A

[*] 1mR of exposure = good amount for any system

Answer 134

A

Sensitivity numbers in a Dia-positive- Fuji system range 50-200 (can be stretched to 200-400)

Inversely related to amount of exposure received

S number 200 ~ 1mR exposure

S number 20 ~ 10 mR exposure

As S# goes up, exposure goes down
As S# goes down, exposure goes up
When S# doubles, the exposure changes by decreasing one half

(fig. 32-2, 32-3, 32-4)

Answer 135

A

[Grids]

Should be used on most projections

Must be 156 lp/mm, buckys are only 108, not enough

All portable must be done with grids, linear non focused

When using AEC, 15% increase in exposure is needed

Answer 136

A

Exposure index in a Positive- Kodak system range 1000-2000

Directly related to amount of exposure received

Exposure Index of 2000 ~ 1mR exposure

Exposure Index of 3000 ~ 10mR exposure

• Doubling of exposure = 2300 = 2mR
• Halving the exposure = 1700 = 0.5mR
+/- 300

Answer 137

A

[Technical Factors]

Optimal keV of 35-50, for highest DQE

Should not exceed kVp of 80-100, due to scatter and decreased DQE

Changes of 2 keV can affect image quality and exposure

Due to linear H & D curve, one can increase ___ to increase exposure and DECREASES dose without negative impact on contrast

Answer 138

A

diapositive

Answer 139

A

(DI) deviation index

number of 0 = where you should be

numbers go up = exposures go up
numbers go negative = exposures go down

(32-4)

Answer 140

A

[Scanned Projected Radiography- SPR]

developed by GE Medical Systems, used for CT (to reference

Tube is set opposite a row of detectors. X-ray beam is collimated into a fan beam for little divergence. The patient is moved through the beam and an image is formed.

Resolution is less than conventional, but contrast is better (due to wide beam).

Detectors can be gas filled ionization chambers or solid state photodiodes (scintillation crystals)

Answer 141

A

InDirect-Capture Radiology (steps to get to DR)

Utilize a flat panel image receptor the size of a regular cassette. An active array matrix (TFT) is used.

CsI/GdOS is coated over a matrix of a-Si photo diodes. 
• X-ray -- CsI/GdOS produces light--  
a-Si produces signal --  TFT stores
signal held until readout one pixel 
at a time.

CsI for extremities
GdOS for chest and everything else

a-Si = amorphous silicon, represents pixels, pixel sizes never change unlike in CR

Better DQE but w/ split pixels

Answer 142

A

The gray part is the active part, a certain portion of each pixel is called active space

Part of that pixel, the white boxes in the corners are the electronics that are required (dead-space)

The a-SI is the only part that can take in info, a high active area, and little dead space, what that means is in a certain area, if 90% can take in info and 10% is dead, that’s good. Iff a diff arrangement, 30% info and 70% dead, not good. Fill factor

Answer 143

A

less fill factor = MORE technique (more noise)

more fill factor = LESS technique

Answer 144

A

[In Direct-Capture Radiology]

Charged Coupled Devices (CCD)

Photodetector typically used with a screen Scintillator

Requires optical coupling by lenses or fiber optics

CCD captures light emitted by Scintillator (CsI/GdOS) and stores it as an electrical signal

Signal is read out in a linear pattern

Electric signal from CCD sent to computer

Answer 145

A

light sensitive chips

take in light and send out electronic signal that can be digitized for the computer

Answer 146

A

If indirect, we has a phosphor, crystal, or light that is then digitized

disadvantage is some loss of info

Answer 147

A

[Direct-Capture Radiology]

a-Se is directly interacted with by x-ray
x-ray-> a-Se produces electron hole pairs –
this signals TFT– signal stored
until readout –one pixel at a time

advantage is no light diversion as
seen in CsI/GdOS coated a-Si
each TFT represents one pixel
in our image

LESS steps = LESS loss = LESS light = LESS divergence

TFT = dead spot
Septa = lines between capture elements

Disadvantage = higher pt. dose, doesn’t absorb higher energy x-ray

Usually in found in mammo

low kVs
most narrow line spread function (better spatial resolution)

Answer 148

A

a-Se = used in direct-capture radiography

a-Si = used in indirect-capture radiography

Answer 149

A

[Digital preprocessing]

Largely automatic

Designed to produce artifact free digital images

Pixel interpolation- if there is a dead pixel, those around it are averaged to create pixel data.

Answer 150

A

[Digital preprocessing]

Lag correction- seen after a high dose exam when switching to a low dose exam, and offset voltage is used to prevent artifact. (some info was left on TFTs and gets subtracted out)

Noise Correction- caused by voltage variations along electrical connections, voltage correction is applied.

Offset images happen daily, Gain images occur monthly. Provide uniform IR response. (take image with a filter over it to calibrate it)

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