Ct Exam 2

Front 1

Changes a time domain signal into a frequency domain signal

Back 1

Fourier Transform

Front 2

Measure of the total absorption of x-rays along a straight line is referred to as:

Back 2

ray sum

Front 3

Basic problem in CT is the calculate:

Back 3

ms for tissues form a large set of projection data

Front 4

Horizontal ray sums for the pixels shown below are:

> 2 3 0 1 5 2 >

Back 4

13

Front 5

Back-projection technique results in:

Back 5

-classical star pattern in the image

-image blur

-poor image quality and, therefore, a diagnosis cannot be made

Front 6

CT scanners now use the:

Back 6

filtered back-projection algorithm

Front 7

Image date are obtained:

Back 7

after back-projection

Front 8

The first operation to which raw data are subjected is referred to as:

Back 8

convolution

Front 9

Belongs to class of analytic algorithms for CT:

Back 9

Filtered back-projection

Front 10

purpose of Ct imaging system is to:

Back 10

1. Convert x-rays into digital data.

2. Detect and measure the radiation transmitted through the patient.

3. Produce, shape, and filter the x-ray beam.

Front 11

Houses the x-ray tube and detectors:

Back 11

Gantry

Front 12

Components of the imaging system:

Back 12

1. x-ray tube

2. collimator

3. detectors

Front 13

Generator used in modern CT scanner:

Back 13

High-frequency

Front 14

Computer and image-processing systems of a CT scanner system consist of all of the following:

Back 14

1. software

2. hardware

3. processing architecture

Front 15

A hard copy (film image) is produced by a:

Back 15

laser imager (printer)

Front 16

On the control consule what controls picture contrast?

Back 16

window controls (WW-window width)

Front 17

CT software refers to all of the following:

Back 17

1. UNIX

2. Operating systems

3. Applications software

Front 18

Modular design concept is intended to:

Back 18

Simplify upgrading of scanners

Front 19

A hardware option for CT scanners is:

Back 19

independent workstation.

Front 20

The CT gantry houses all of the following except:

-the couch

-the gantry

-the xray tube

-the CPU

Back 20

The CPU

Front 21

Imaging system components are located in the:

Back 21

Scan room

Front 22

Purpose of the imaging system is to perform all of the following except:

-produce x-rays

-store images for retrieval

-collect attenuation data

-collimate the x-ray beam

Back 22

Store images for retrieval

Front 23

Digital image processing technique used to

modify images through a filter function

Back 23

Convolution

Front 24

Where images are stored in a filmless imaging department

Back 24

PACS

Front 25

Method of image compression that results in no loss of information during the compression process:

Back 25

Lossless

Front 26

Describes the beam that diverges from the x-ray tube to the outer edges of the detectors

Back 26

Cone beam

Front 27

Set of ray sums is:

Back 27

projection

Front 28

Removes the classical star pattern of the back-projection algorithm:

Back 28

Filtered back projection

Front 29

Result of preprocessing of the signals from the CT detectors is called:

Back 29

Raw data

Front 30

Refers to a defined set of instructions for solving a problem

Back 30

Algorithm

Front 31

First operation to which raw data is subjected to is:

Back 31

Convolution

Front 32

Opening in the gantry in which the patient is

positioned during scanning is:

Back 32

Aperature

Front 33

Mathematical technique used to estimate the value of a function form known values on either side of the function:

Back 33

Interpolation

Front 34

concept of modular design in CT scanner

development is intended to:

Back 34

Simplify upgrading of the scanner

Front 35

Gray-level mapping is also referred to as all of the following except:

-Contrast stretching

-Windowing

-Image enhancement

-Histogram modification

Back 35

Image enhancement

Front 36

In CT, windowing is an example of:

Back 36

gray-level mapping (control control)

Front 37

In CT, the window width (WW) is the:

Back 37

Range of CT numbers

Front 38

The window level (WL) in CT is defined as the:

Back 38

Middle of the range of CT numbers

Front 39

The contrast of the CT image is controlled by:

Back 39

Window Width (WW)

Front 40

The brightness of the image can be altered by the:

Back 40

Window Level (WL)

Front 41

When the Window Level (WL) changes from -100 to +400, the picture changes from:

Back 41

white to black

Front 42

The software program that generates sagittal and coronal images from the transaxial dataset is referred to as:

Back 42

Multidectector CT

Front 43

Which of the following is NOT an example of a basic visualization tool?

-image magnification

-statistics

-CT histogram

-3D imaging

Back 43

3D imaging

Front 44

The following are example of advanced

visualization software tools except:

-3D imaging

-CTA

-split imaging

-virtual reality imaging

Back 44

split imaging

Front 45

Determines image quality:

Back 45

-spatial and contrast resolution

-noise

-artifacts

-radiation dose

Front 46

The unit for spatial resolution of a CT scanner is:

Back 46

line pairs per cm=

lp/cm

Front 47

The capability of the CT scanner to discriminate small differences in tissue contrast is:

Back 47

contrast resolution

Front 48

Spatial resolution of the FBP algorithms is affected by all of the following except:

-detector cell width

-size of the focal spot

-slice thickness

-photon flux

Back 48

photon flux

Front 49

Slice thickness can be measured by:

Back 49

Shallow-angled slice ramp

Front 50

the pixel size in CT is equal to:

Back 50

FOV/ divided by/ matrix size

Front 51

CT number fluctuation from pixel to pixel in the image for a scan of water phantom is referred to as:

Back 51

noise

Front 52

To reduce noise (standard deviation) by a factor of 2, the dose must be increased by a factor of:

Back 52

4

Front 53

Which of the following produces a streak

artifact:

1. aliasing

2. metal objects

3. motion of the patient

Back 53

all

Front 54

Ring artifacts in CT arise from:

Back 54

One of more bad detector cells