Advanced Image

Question 1

what is derived from the greek word “tomes” meaning section

Answer 1

tomography

Question 2

ct provides views from _ planes

Answer 2

coronal
axial
sagittal

Question 3

these cuts or slices are often only _ thick

Answer 3

mm

Question 4

there are _ generations of CT machines

Answer 4

4

Question 5

first generation systems had only _ detector and only rotated _ degrees

Answer 5

one

180

Question 6

second generation improved the _ of detector and used a _ shaped beam

Answer 6

#
fan

Question 7

third and fourth generation systems used _ detectors, (_) and _ degree

Answer 7

many
900-4800 (detectors)
360

Question 8

early CT systems were limited to

Answer 8

rotating in one direction only

Question 9

what were added to allow the tube to continuously rotate while the patient moved through the gantry

Answer 9

slip rings

Question 10

this describes “_” and increases the _ while decreasing _

Answer 10

volume scanning
data produced
scan time

Question 11

multi slice scanners were introduced in

Answer 11

1998

Question 12

multi slice CT produce _

Answer 12

4 image slices simultaneously

Question 13

for multi slice scanners currently as many as _ slices may be produced from a _ x-ray tube rotation

Answer 13

64

single

Question 14

advantages of multi-slice scanners

Answer 14

shorter acquition time
decreased volume of contrast media
improved spatial resolution
improved image quality as well as thinner slices

Question 15

disadvantages of multi-slice scanners

Answer 15

increased cost (30-50%)

Question 16

there are three basic parts of the CT scanner

Answer 16

gantry
computer
operator console

Question 17

similar to a basic x-ray tube modified to rotate in 360 degrees and withstand higher heat loading

Answer 17

x-ray tube

Question 18

solid state detector composed of photodiodes with crystal scintillation materials

Answer 18

detector array

Question 19

set of 2 collimators one pre-patient and one post-patient

Answer 19

collimator assembly

Question 20

the collimator assembly do what to the beam

Answer 20

shape and limit the size and direction of the beam

Question 21

the gantry has three components

Answer 21

x-ray tube
detector array
collimator assembly

Question 22

the CT requires _ types of sophisticated software

Answer 22

2

Question 23

the 2 types of software is

Answer 23

one for the operating system

one for the applications

Question 24

the operating system is a

Answer 24

window base program controls the hardware

Question 25

application software manages

Answer 25

the image processing, reconstruction and post-processing operation

Question 26

the operating console includes a

Answer 26

keyboard, mouse, and monitors

Question 27

this allows the tech to _ and _

Answer 27

control the system | set the parameters of the exam

Question 28

this is termed the _ and includes

Answer 28

protocol | kV, mA, FOV, pitch, slice # and thickness image reconstruction and display

Question 29

a computer is often set with more than one _ these are _ and allow the tech and radiologist to view the CT images

Answer 29

workstation linked (networking and archiving)

Question 30

these station may be located on _ or be

Answer 30

site | remote areas w/electronic transmission of data

Question 31

the display matrix is a digital image composed of pixels in two dimensions to represent a three dimensional piece of tissue

Answer 31

volume element

Question 32

three dimensional volumes of tissue are called

Answer 32

volume elements or voxels

Question 33

what is selected by the tech

Answer 33

the depth of the voxel

Question 34

each voxel in a slice is assigned a _ by the computer that is _ to the degree of x-ray attenuation of that area

Answer 34

number value | proportional

Question 35

once the degree of attenuation is set the image is displayed on the scree as a _ with each voxel being presented as a pixel on the screen

Answer 35

two dimensional picture

Question 36

the computer uses a _ to determine the degree of x-ray attenuation for each voxel

Answer 36

linear coefficient

Question 37

this value is then converted into a numeric scale called

Answer 37

CT #'s

Question 38

shades of gray are assigned to each CT # with the base value being

Answer 38

0

Question 39

water is set as the

Answer 39

base value

Question 40

window width and window level refers to the

Answer 40

grayscale and brightness of the display

Question 41

a wide window width indicates a

Answer 41

long scale of gray(contrast)

Question 42

is determined by the tissue density most common to an area w/in that anatomic structure

Answer 42

window level

Question 43

the tube/detector array and the pt. are in _ during the scan. The amount of anatomy scanned is determined by _

Answer 43

continuous motion | pitch

Question 44

Pitch is

Answer 44

couch movement (mm/sec)/rotation of the tube collimation

Question 45

undesirable density on the image

Answer 45

artifact

Question 46

computed tomography

Answer 46

CT

Question 47

value set for each pixel in the image relative to water

Answer 47

CT #

Question 48

houses the tube, detectors and collimators

Answer 48

gantry

Question 49

numerical expression of the radiation intensity through matter

Answer 49

linear attenuation coefficient

Question 50

total # of pixels in the image (rows and columns)

Answer 50

matrix

Question 51

MPR is

Answer 51

multi-planar reconstruction

Question 52

refers to the parameters of the exam

Answer 52

protocol

Question 53

one section of the object being scanned

Answer 53

slice

Question 54

device that allows the continuous rotation of the tube during the scan

Answer 54

slip rings

Question 55

CT data taken while the pt. moves uninterrupted through the gantry

Answer 55

volume scanning

Question 56

three dimensional piece of tissue

Answer 56

voxel

Question 57

computer that serves as the digital post processing station and or image viewing area

Answer 57

workstation