Image Production- Basics And Scan Modes

Question 1

On the basis of what can an image of an object be reconstructed and occurs as radiation is transmitted through that object?

Answer 1

Attenuation

Question 2

What rotated around the patient, exposing a given volume of tissue from all directions?

Answer 2

X-ray beam

Question 3

What measures the radiation that is transmitted through the patient?

Answer 3

Detectors

Question 4

What is based on the magnitude of X-ray attenuation that occurs at spatially distributed points within the patient?

Answer 4

Magnitude

Question 5

What are the 4 major steps to the general process of CT imaging?

Answer 5

Data acquisition, data reconstruction, multidimensional image display, and image archival and communication

Question 6

Measurement of the attenuation that occurs along each path through the patient from X-ray tube to detector?

Answer 6

Data acquisition

Question 7

Computerized processing of the transmission measurements into the CT image?

Answer 7

Data reconstruction

Question 8

Display of the reconstructed grayscale image in 2D and 3D format; representation of the attenuation that occurred across the scanned volume of tissue?

Answer 8

Multidimensional image display

Question 9

Display as well as storage, both short-term and long-term, of images on computer workstations?

Answer 9

Image archival and communication

Question 10

What is the most basic scan mode utilized by a CT system?

Answer 10

Scout image

Question 11

How are the tube and detectors fixed around the patient for a scout image?

Answer 11

Stationary

Question 12

What are two other names for a scout?

Answer 12

Scan organ or localizer

Question 13

What positions may a scout image be reproduced in?

Answer 13

AP, PA, lateral, or oblique

Question 14

What is a term describing the angle of the tube and detectors in relationship to the patient position during a scout acquisition?

Answer 14

Azimuth

Question 15

What scanning method involves a complete revolution of the X-ray tube around the patient, acquiring a single data set at a certain location?

Answer 15

Axial/conventional

Question 16

What is another name for axial scanning?

Answer 16

Step-and-shoot

Question 17

How does axial acquisition work to obtain data?

Answer 17

Patient is scanned when table is not moving, data processed, table moves patient into next position, patient is scanned, and so on.

Question 18

What three components make up the CT system?

Answer 18

Powerful computer and display system, patient bed, gantry components

Question 19

What components are housed within the CT gantry?

Answer 19

Generator, X-ray tube, assorted collimators, DAS, slip-rings and detectors

Question 20

What were the CT systems originally composed of that prevented continuous rotation in the gantry?

Answer 20

Hardware cables

Question 21

What new CT technology eliminated the need for cables by utilizing a system of contact brushes that supply electricity to power the system and enable passage of transmission data to the computer?

Answer 21

Slip-ring technology

Question 22

What new type of image acquisition was made possible by slip-ring technology?

Answer 22

Helical scanning

Question 23

What are 4 technical elements of helical CT acquisition?

Answer 23

Continuous rotation of the gantry components (slip-rings),
Tube capable of long exposure output, continuous movement of patient bed,
Specialized mathematical reconstruction techniques

Question 24

What type of data acquisition is allowed for by helical geometry?

Answer 24

Volumetric

Question 25

What is image reconstruction slice thickness controlled by, makes the width uniform, and is set before acquisition?

Answer 25

Collimation