Week 1 - Intro To CT

Question 1

Process of producing an image of a 2 dimensional distribution from estimates of its line integrals along finite number of lines of known locations

Answer 1

Image reconstruction

Question 2

Reformatting into a different plane

Answer 2

MPR
Multi planar reformatting

Question 3

Greek for cutting/section

Answer 3

Tomos

Question 4

Researchers were attempting to acquire “body section radiography”

Answer 4

1920s

Question 5

Grossman refined the technique and labeled it tomography

Answer 5

1935

Question 6

Preliminary image
Lateral and AP

Answer 6

Topogram, scout, scanogram

Question 7

Continuous acquisition scanning

Answer 7

Spiral, helical, isotropic

Question 8

Done before any scan to figure out anatomy, done AP and lateral, also done to ensure Isocentering

Answer 8

Scout, scanogram, topogram

Question 9

What are some differences between CT and radiography?

Answer 9

CT images show cross sectional anatomy
CT produces 3D images that are computer generated with use of transaxial dataset

Question 10

Changing from 2D to 3D

Answer 10

Reconstructing

Question 11

Changing from one plane to another

Answer 11

Reformatting

Question 12

T/F
Radiography can not distinguish between tissues with <10% tissue contrast

Answer 12

True

Question 13

What is the goal of CT?

Answer 13

-minimize superimposition
-improve image contrast
-record small differences in tissue contrast

Question 14

Determined the thickness of the slice

Answer 14

Z axis
Determined by use of collimators

Question 15

Indicates width of slice

Answer 15

X

Question 16

Indicated height of slice

Answer 16

Y

Question 17

Adding what to X and Y make it a voxel?

Answer 17

Z

Question 18

What are some limitations of CT?

Answer 18

Poorer spatial resolution
Higher dose
Beam hardening artifacts
Streak artifacts

Question 19

What is temporal resolution particularity important for?

Answer 19

Cardiac imaging

Question 20

A horizontal plane that passes through the body, dividing it into superior and inferior portions

Answer 20

Axial / transverse
*all CT images are acquired in axial

Question 21

A vertical plane that passes through the body, dividing it into right and left portions

Answer 21

Sagittal

Question 22

A vertical plane that passes through the body, dividing it into anterior and posterior portions

Answer 22

Coronal

Question 23

A plane that passes diagonally between axes of two other planes

Answer 23

Oblique

Question 24

Formation of CT images involves 3 steps:

Answer 24

-data acquisition
-image reconstruction
-image display

Question 25

Collection of xray transmission measurements from the patient

Answer 25

Quantitative

Question 26

Detector moves around the patient at a particular section. Table then moves and the detector moves around the patient again

Answer 26

Axial

Question 27

Xray tube and detectors continuously rotate as the patient moves through the scanner simultaneously

Answer 27

Helical

Question 28

Radiation passes through sections of the body and sends signals to CPU from the detectors

Answer 28

Image reconstruction

Question 29

First CT developed

Answer 29

1971 20 minutes per image

Question 30

First patient was scanned

Answer 30

1972

Question 31

What is a benefit of a dual source CT?

Answer 31

Excellent spatial and temporal resolution

Question 32

Acquiring a volume of tissue during the scanning

Answer 32

Volume scanning

Question 33

Artifacts that result from preferential absorption of the low energy photons, which leaves high intensity photons to strike the detector array

Answer 33

Beam hardening artifacts

Question 34

What materials can be used for filtering?

Answer 34

Teflon or aluminum