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1
Q

……. Allows for continuous gantry rotation.

A

Slip ring

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2
Q

Tomo

A

Slice

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3
Q

Ring artifact shows in which CR generation

A

3rd

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4
Q

Rotating beam on a stationary detector is in which generation

A

4th

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5
Q

Three main components of CT system

A

Operating console
Computer
Gantry

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6
Q

The time from the end of imaging to the appearance of the image

A

Reconstruction time

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7
Q

Houses the x-ray tube, detector array slip rings, data acquisition system, and high-voltage generator

A

Gantry

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8
Q

What is the main cause of CT malfunction

A

Tube failure (overheating)

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9
Q

CT tube KVP

A

70-140 kvp

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10
Q

A grouping of detectors is called…

A

Detector array

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11
Q

Previously ……. Detectors were used. M DCT now require…… detectors

A

Gas filled
Scintillation

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12
Q

What does DAS stand for?

A

Data acquisition system

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13
Q

What is the function of DAS?

A

Amplifies the detector signal

Converts the analog signal to digital

Transmits the digital signal to the computer 

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14
Q

Collimation function

A

 Reduce patient does

Improve image contrast, while limiting scatter

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15
Q

What are two types of collimation?

A
  1. pre-patient 
  2. post patient
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16
Q

Which which one determines does profile: pre-patient or post patient collimation?

A

Pre-patient

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17
Q

Which one controls patient does?
Pre-or post collimation ?

A

Pre- collimation

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18
Q

What is the patient couch or table made out of

A

Carbon fiber, low atomic number

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19
Q

What is pitch in CT exam?

A

How fast patient goes through gantry.
Table movement / detector width 

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20
Q

If we increase the pitch what happens to patient does

A

It decreases

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21
Q

What happens if pitch is less than one

A

Overlap of information

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22
Q

DFOV stands for

A

Detector field of view

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23
Q

What does post patient collimation do?

A

Reduces scatter

Controls slice thickness

Defines sensitivity profile or a slice thickness

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24
Q

CT opening

A

Gantry aperture

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25
Three steps in CT
Data acquisition. Image reconstruction. Image display.
26
Rotate rotate with fan beam . Which generation
3rd
27
What type of detector do we use
Scintillation
28
What measures photons and converts them to digital signal
DAS Data Acquisition System
29
Ctdi stands for
Computed tomography dose  index
30
Describes the amount of radiation given off by the CT scanner doing a singular scan
CTDI
31
Does CTDI quantify patient does
No, it’s quantifies output of system
32
Unit of measurement for CTDI
mGy
33
What does D LP stands for?
Does length product
34
What is the DLP?
Describes the amount of radiation deposited in a patient during an exam 
35
An automatic exposure mechanism that adjusts tube output to compensate for differences in patient’s size Calculated via the scouts image of
Automatic tube current modulation
36
Factors affecting dose in CT
MAS KVP over 120 Pitch : higher pitch lower dose Collimation : more collimation, less dose 
37
What happens if patient is too high in the gantry?
Assumes patient is large and uses higher technique
38
Patient in the center of the country is called….
Iso centric
39
Ability to differentiate different densities on an image
Contrast resolution
40
Measure of the size of a smallest object that can be visualized on an image. measured in line pairs.
Spatial resolution
41
What effects spatial resolution?
Focal spot size Pixel size Detector size Collimation
42
Temporal resolution
Measurement of time speed of gantry rotation Faster, a rotation, better temporal resolution
43
CT scanners ability to resolve details on a moving object
Temporal resolution
44
Picture element
Pixel
45
Volume element
Voxel
46
HU of air
-1000
47
HU of fat
-100
48
HU of water
0
49
HU of CSF
0-10
50
HU of Blood
55-75
51
Hu of white matter
20-30
52
HU of grey matter
55-75
53
HU of calcium
200-1000
54
Hu of metal
More than 1000
55
What’s the range for HU
-1000 to +3000
56
Window width controls ..,,,,
Image contrast
57
Wider window width higher or lower contrast ?
Longer grey scale and lower contrast
58
Small window higher or lower contrast
Less shades of grey more contrast
59
Prospective image
The image created from the parameters you set up in your protocols Scan all raw data
60
Retrospective image
An image created by manipulating raw data, collected to change the appearance in your image, reconstruction, (image data)
61
Mathematical process used to process a scan information into display image
Algorithm
62
How can you show metal artifacts better in CT imaging?
Lower pitch, higher, KV
63
An artifact caused by a scanning different tissue thickness is
Partial volume effects Blurs edges of anatomy 
64
How can we correct partial Valium affect?
By using thinner slices so bone and soft tissue are not on the same slice
65
How often we scan water phantom ?
Daily
66
How often QC for spatial and contrast resolution?
Monthly
67
Four important items to check for the history of patient in CT
1. Diabetes. 2. Iodine allergy. 3. Chance of pregnancy. 4. Chronic kidney disease.
68
Enteral means ?
Within or by way of intestine Oral Rectal Ng tube
69
Parenteral
Meds by injection, rather than orally Intravenous Intramuscular subcutaneous Medication’s are absorbed more rapidly than oral
70
Intrathecal
Performed post myelogram
71
G.I. stand for
Gastro intestinal
72
Is barium sulfate positive or negative contrast
Positive
73
Is iodinated oral contrast, positive or negative
Positive
74
Name two negative contrasts used for G.I. tract
CO2, air, water
75
What is barium peritonitis?
Leaking of barium into the peritoneal cavity
76
Examples of two water soluble iodinated oral contrast
Gastroview Gastrografin
77
 Phases of data acquisition
Arterial phase . 25 to 30 seconds after injection. Venus phase 60 to 80 seconds after Delete phase 92/300 seconds after injection
78
Extravasation
Leakage of IV contrast into surrounding tissues
79
What are the steps when extravasation happens?
Stop injection immediate Cold compress, warm compress Consult radiologist
80
Normal levels of blood urea nitrogen or BUN
7 to 23 mg/dl
81
Normal levels of creatinine
0.8 to 1.5 mg./dl
82
No IV contrast in creatinine is above
2
83
What level of GFR glomerular filtration rate is considered normal
Above 60
84
What level of GFR is safe to use IV contrast?
40-60
85
What do you do in case of it Contra’s reaction
Call Code if needed Have crash carts available Document reactions : Progress of patient’s condition Persons present Drug given Disposition of case 
86
Medication used to counteract reactions or
Anti-histamines like diphenhydramine (Benadryl)
87
What medication do we use if patient has severe allergic reactions and doesn’t respond to antihistamines
Corticosteroids
88
Medication which is used to counter act as severe allergic reaction such as shock or respiratory arrest
Epinephrine

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