Brainscape's Knowledge GenomeTM

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


See full index

CT > Image Formation > Flashcards

Image Formation Flashcards

1
Q

Who discovered X-rays?

A

Wilhelm Rontgen

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

Types of electromagnetic radiation

A

radiowaves, microwaves, infrared, visible light, ultraviolet light, X-rays and gamma rays

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

Shorter wavelengths have higher ___________, which results in __________ energy of the traveling photons.

A

Frequency, Increased

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

Range of electrovolts in X-rays

A

100 eV - 100 keV

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

Measure of change over a single period of time in a Sine Wave

A

Amplitude

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

The number of occurrences of a relating event per unit of time, expressed as cycles per unit of time

A

Frequency

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

Range of X-ray energy frequencies

A

30 petahertz to 30 exaherts

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

5 Forms of interaction w/ matter

A
  1. Coherent Scatter
  2. Compton Effect
  3. Photoelectric Effect
  4. Pair Production
  5. Photodisintegration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

An x-ray photon interacts with the whole atom causing the atom as a whole to become excited, known as classical or thompson scatter. X-ray energy levels below 10 kiloelectrovots

A

Coherent Scatter

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

The minimum kVp setting on most CT scanners

A

80 kVp

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

X-ray photon interacts with an outer shell electron knocking it out of orbit

A

Compton Scattering

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

X-ray interacts with outer shell electron, knocking it out of orbit ionizing the atom producing a ___________

A

compton electron

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

Single projection image with large field of view

A

Localizer (scout, surview, tomogram, scanogram)

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

Used to specify perfectly transverse slices (abdomen, pelvis, chest)

A

AP Localizer

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

Used if the gantry needs to be at an angled to specify oblique slices (head and spine)

A

Lateral Localizer

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

Scan produced by the X-ray tube rotating around the stationary patient, then having the patient table move along the Z-axis at a specific distance before taking the next set of images.

A

Conventional Scan (axial scan, sequential scan, serial scan, step and shoot)

17
Q

Type of scan that produces the best image quality.

A

Conventional Scan

18
Q

Studies that still use Conventional Scanning

A

Neurological exams, Obese Patients, Cardiac Calcium Scoring

19
Q

Scan mode used by having the X-ray tube rotate around the patient as the patient table moves at a specific speed determined the Pitch setting

A

Helical Scan (spiral scan, volumetric scan)

20
Q

Advantages of Helical Scanning

A

Faster scan times
Made Coronary and Cardiac studies possible
More coverage in a single breath hold (less motion artifact)
Less contrast required
Arbitrary slice positioning
Ideal type of data for post-processing

21
Q

2 factors that influence the path of the X-ray beam

A

Pre-patient collimation & Focal Spot

Speed of the patient table

22
Q

Mathematical calculations used to divide the helical data into individual slice planes and placed in a raw data file.

A

Interpolation

23
Q

Required to convert the helical path to transverse slices

A

Interpolation

24
Q

What is a limiting factor with short scan that have high mA and quick rotation times?

A

Extreme Heat (causing scan delay)

25
Q

What is responsible for image noise?

A

mAs (increase for less noise)

26
Q

What is used to achieve proper tissue contrast?

A

kVp

27
Q

In serial scanning, slice thickness that is equal to table increment is known as __________

A

Contiguous

28
Q

What is the result when the table increment is reduced to half the slice thickness in serial scanning?

A

50% overlap

29
Q

What is the result when the table increment is more than the slice thickness in serial scanning?

A

A Gap

30
Q

During helical scanning, what determines the table movement and anatomical coverage of the patient?

A

Pitch

31
Q

What value is the pitch set to when there is no overlap during helical scanning?

A

Pitch = 1

32
Q

On a SSCT, what defines the table movement in 1 gantry rotation divided by slice thickness?

A

Pitch

33
Q

On a MSCT, what equals the table movement in 1 gantry rotation divided by beam width?

A

Pitch

34
Q

Number of active detector arrays multiplied by slice thickness

A

Beam Width

35
Q

Movement of table in one gantry rotation divided by acquired slice thickness

A

Pitch

36
Q

What is affected by Pitch?

A

Anatomical coverage

CT (3 decks)

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