Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

spring 2015 > Physics Chapter 14 > Flashcards

Physics Chapter 14 Flashcards

1
Q

Know the two ways that image intensifiers improved the image process

A
  • Brightened the image significantly (eliminated the need to dark adapt)
  • Allowed for a means of immediately viewing the fluoro image (reduced radiographic dose)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Know what the conventional fluoroscopic chain consists of

A

x-ray tube, an image intensifier, a recording system, and viewing system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Know the 5 basic parts that make up an image intensifier

A

Input phosphor, photo cathode, electrostatic focusing lenses, accelerating anode, and output phosphor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Know why the input phosphor is made of cesium iodide

A

It absorbs remnant x-ray photon energy and emits light in response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Know the size correlation between the input and output phosphor

A

output phosphor is much smaller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Know how brightness gain has traditionally been found

A

Multiplying the flux gain by the minification gain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Know the size of the image intensifier tube

A

50 cm in length and 15-58 cm diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Know how flux gain is expressed

A

The ratio of the number of light photons at the output phosphor to the number of light photons emitted in the input phosphor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

WHat results from the higher the conversion factor or brightness gain factor

A

image appears brighter because the same number of electrons is being concentrated on a smaller surface area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Know what happens as the image intensifier tube ages

A

The ability of the image intensifier to increase brightness deteriorates with the age of the tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Know what happens in regards to radiation as the image intensifier tube ages

A

More and more radiation is necessary to produce the same level of output brightness, translating to an increased patient dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Know how ABC commonly operates

A

By monitoring the current through the image intensifier or the output phosphor intensity and adjusting the exposure factor if the monitored value falls below preset levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Know how to find the degree of magnification

A

Dividing the full size input diameter by the selected input diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Know what magnification improves

A

The fluoroscopist’s ability to see small structures (spatial resolution) but at the expense of increasing patient dose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Know how spatial resolution is measured

A

Line pairs per millimeter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Know what distortion is a result of in fluoro

A

Inaccurate control or focusing of the electrons released at the periphery of the photocathode and the curved shape of the photocathode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define a pincushion appearance

A

The combined result is an unequal magnification (distortion) of the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Know how a “noisy” or “grainy” image occurs

A

If too few x-rays exit the patient and expose the input phosphor, then not enough light is produced, which decreases the number of electrons released by the photocathode to interact with the output phosphor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Know how to fix a “noisy” image

A

increasing the mA

20
Q

Know what the 2 devices are that convert the image from the output phosphor to an electrical image

A

The camera tube and charge-coupled device (CCD)

21
Q

Know what the camera tube most often used is

A

vidicon tube

22
Q

Know what the deflection coils act to accelerate

A

the electron beam

23
Q

Know what the CCD is made from

A

A series of metal oxide semiconductor capacitors

24
Q

Know what is sent from the capacitors

A

Charge is sent as an electronic signal to the tv monitor

25
Q

Know what the purpose of the television monitor is

A

Convert the electrical signal from the camera tube to CCD back into visible light

26
Q

Know what typical television monitors are called

A

525 line systems

27
Q

Know the resolution of HIGH resolution monitors

A

1024 lines per frame

28
Q

Know what the image intensifier is capable of resolving

A

Approximately 5 lp/mm whereas the monitor can display only 1-2 lp/mm

29
Q

Know the 3 types of recording systems

A

Cassette sport film, film cameras, video recorders

30
Q

Know what happens when the spot film exposure button is pressed

A

The cassette is moved into position between the patient and image intensifier and the machine shifts from fluoroscopic to radiographic mode and exposes the film

31
Q

Know what happens in regards to radiation dose when imaging from fluoro to radiographic mode

A

fluoro to the radiographic mode uses a much higher radiation dose to the patient

32
Q

Know what film is commonly used in the film cameras

A

105 mm “chip” film or 70 mm roll film

33
Q

Know what the number of bits that a signal is divided into determines

A

the contrast resolution (number of gray shades) of the system

34
Q

Know what the charge-coupled device (CCD) eliminated

A

Some of the problems associated with the camera tube

35
Q

Know the 2 forms of flat panel detectors are used for fluoroscopic applications

A
  • cesium iodide amorphous silicon indirect capture detector

* amorphous selenium direct capture detector

36
Q

Know why the size, bulk, and weight of the fluoroscopic tower in digital fluoro is an advantage

A

Flat panel reduces all 3 allowing easier manipulation of tower, greater flexibility of movement and greater access to the patient during the exam

37
Q

Know what the flat-panel detectors replaced

A

the spot0filming and other recording devices

38
Q

Know why additional radiographic images are commonly not needed in digital fluoroscopy

A

they are capable of operating in radiographic mode

39
Q

Be able to describe some of the other advantages of digital fluoro

A
  • flat panel detectors don’t degrade with age
  • more durable
  • provide more information
  • better contrast resolution
  • higher detective quantum efficiency
  • wider dynamic range
40
Q

Know the advantage of digital fluoro in regards to artifacts

A

They do not exhibit most image artifacts such as veiling glare and peripheral distortion seen with image intensifiers

41
Q

Know the advantage of digital fluoro in regards to radiation dose

A

50% lower radiation dose

42
Q

Know why Quality Control Programs are vitally important for all ionizing radiation producing equipment

A

to monitor equipment performance and minimize patient dose

43
Q

Know the role of the radiologist in a quality control program

A

supervision of the whole quality control program and process

44
Q

Know the role of a radiographer in a quality control program

A

facilitator in the process

45
Q

Know the role of the medical physicist in a quality control program

A

has primary responsibility for performance testing and interpretation

46
Q

Know some of the responsibilities a radiographer may have in a quality control program

A
  • Operational inspection of the equipment
  • inspection of suite itself to examine the general physical condition of the room, unit, supporting electrical cables, and control booth, monitoring anywhere or deteriorating condition
  • performance inspection and testing equipment
  • Check following items
  • bucky slot cover
  • table tilt motion
  • monitor brightness
  • exposure switch

spring 2015 (43 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions