Computed Tomography

Question 1

What kind of beam does 1st Gen CT produce?

Answer 1

Pencil Beam

Question 2

in 1st gen, required ____ translations in _ degree increments

Answer 2

180, 1

Question 3

which gen takes 5 minutes to complete?

Answer 3

1st

Question 4

1st and 2nd gen CT are considered to be…

Answer 4

Translate-rotate

Question 5

this generations of ct produces a Fan-shaped beam?

Answer 5

2 and 3

Question 6

this gen of CT use 10 degree increments with 18 translations

Answer 6

2nd

Question 7

How many detectors does the 2nd gen CT have?

Answer 7

5-30

Question 8

3rd gen uses Curvilinear array, which contains….

Answer 8

Detectors and fan beam

Question 9

what is the width of the fan shaped beam in 3rd gen?

Answer 9

30-60 degree

Question 10

which gen of ct produces ring artifact?

Answer 10

3rd

Question 11

4th Gen is the most different, what kind of operation does it uses?

Answer 11

Rotate-stationary

Question 12

Major components of CT imaging system…

Answer 12

Operator console, computer, Gantry

Question 13

Source to detector makes one sweep, this is call

Answer 13

translation

Question 14

Computer component of CT has 2 memory methods, one is random access memory and another is long term

Answer 14

RAM and Archiving

Question 15

what were the different types (in order) of detector arrays?

Answer 15

Gas filled detectors, replaced by Scintillation, Solid State Detectors

Question 16

what are the 2 collimators used in CT?

Answer 16

Prepatient and Predetector collimator

Question 17

this collimator is mounted on the x ray tube

Answer 17

Prepatient

Question 18

how much kW is necessary for a multi slice unit?

Answer 18

50

Question 19

Slip rings make spiral CT possible by…

Answer 19

allowing continuous spin

Question 20

Image matrix refers to cells. Cells are called…

Answer 20

Pixels

Question 21

what is the current matrices?

Answer 21

512x512

Question 22

If numbers of pixels stay the same but field of view is increased, the quality is ______. If the pixels decreases with field of view increase , the quality is _____.

Answer 22

blurry, good

Question 23

Voxel =…

Answer 23

pixel x slice thickness of image slice

Question 24

CT numbers for the following 
Air
fat
water
gray matter
dense bone

Answer 24

-1000 to -3000
-100
0
+40
1000 - 3000

Question 25

what are the 5 principle characteristics of image quality in CT?

Answer 25

Spatial resolution, linearity, contrast resolution, Spatial uniformity, noise

Question 26

what is spatial resolution affected by?

Answer 26

pixel size and collimation

Question 27

shades of gray or ability to distinguish one soft tissue from another is a description of

Answer 27

contrast resolution

Question 28

how does noise artifact appear on CT?

Answer 28

grainy

Question 29

Linearity describes how CT should be calibrated. What method is used to test linearity?

Answer 29

Five pins test

Question 30

Ability to reconstruct an image at any Z axis position by using mathematical equation is called (using known values)

Answer 30

intrapolation

Question 31

but when you're estimating value beyond range of known value it is called...

Answer 31

extrapolation

Question 32

Relationship between pt couch movement and x ray beam width is....

Answer 32

Pitch

Question 33

Axial Tomography is also known as

Answer 33

Conventional Tomography

Question 34

What is inside of a Gantry?

Answer 34

X ray tube, Detector array, data acquisition system, and cooling system

Question 35

This is the numeric information contained in each pixel

Answer 35

CT number/hounsfield unit

Question 36

When the source to detector parts make a scan, this is called a..

Answer 36

Translation

Question 37

when you use math to make and calculate image reconstruction, you are utilizing...

Answer 37

Algorithm

Question 38

When you're talking about matrix decreasing in size or increasing you're talking about...

Answer 38

field of view

Question 39

lower CT number will appear close to ____ while higher number will appear from ____ to ____

Answer 39

black, grey to white

Question 40

this bone forms the lateral walls of cranium

Answer 40

Temporal

Question 41

this bone is found in the eye hole area, right btwn maxilla and labyrinth of the ethmoid bones

Answer 41

lacrimal

Question 42

Vertebral arch is formed by...

Answer 42

2 pedicles, 2 laminae, 2 transverse process, 1 spinous process

Question 43

Trachea originates where?... and splits where?

Answer 43

C6, T4-T5

Question 44

Costophrenic angles are the ....

Answer 44

most posterior and inferior portion of the base

Question 45

what is an S shaped bone?

Answer 45

clavicle

Question 46

What bones make up the acetabulum?

Answer 46

Pubis, ilium, and Ischium

Question 47

What do you call the last cartilage ridge of the trachea

Answer 47

carina

Question 48

When did Hounsfield first demo the CT?

Answer 48

1970

Question 49

in 1979 who did Hounsfield share the Nobel Prize with?

Answer 49

Cormack, Alan

Question 50

which generation of the pt at all times?

Answer 50

3rd gen

Question 51

simplest form of 3D imaging

Answer 51

Maximum intensity projection

Question 52

Sensitivity profile is about ____ than conventional CT

Answer 52

10%

Question 53

2,000-4,000

Answer 53

body

Question 54

3,000-5,000

Answer 54

Head

Question 55

20mGy-40mGy

Answer 55

body imaging

Question 56

30mGy-50mGy

Answer 56

Head imging

Question 57

This is higher in CT than any other x ray procedure

Answer 57

ESE