CT SCAN STUDY GUIDE EXAM
QUESTIONS WITH COMPLETE
ANSWERS
Computed tomagraphy - Answer--merges x-ray technology with the computer to provide
detailed digital cross-sectional images of the body relatively free from superimposition of
the different tissues.
-revolutionized the ability to visualize soft tissues
Principles of CT - Answer--employs x-rays that are attenuated by body tissues. The
radiodensities of the tissues are represented in the image as shades of gray
-creates images based on cross-sectional (axial) slices, created by up to 1000
projections from different angles
Components of CT scanner - Answer-1: the gantry: contains the x ray tube
2:operator's console
3: the computer
The detectors - Answer--x rays are attenuated by body tissues and then exit the pt's
body as remnant radiation, similar to conventional radiography.
-up to 1000 detectors are arranged in an array, encircling the pt, for the purpose of
measuring this remnant radiation
-modern units have 4-16 arrays
Data anquisition system - Answer--amplifies the signal from the detectors
-incoming signal is in the form of a varying electrical current= ANALOG SIGNAL
-system converts it from analog to digital form and then sends it to the computer
Scout image - Answer-2 dimensional digital radiograph-localizes the structures to be
scanned
Pitch - Answer-movement of the tabletop
Represents the ratio of tabletop movement to slice thickness
Volumetric scanning - Answer-large volumes of data with high accuracy and short
imaging times
Not limited to axial plane.
Can be any plane or even 3D, w/out loss of spatial resolution
3D CT - Answer-volumetric scanning
Presentation of body parts can be rotated in "in space" on the computer screen
Process called multiplanar reconstruction (MPR)
QUESTIONS WITH COMPLETE
ANSWERS
Computed tomagraphy - Answer--merges x-ray technology with the computer to provide
detailed digital cross-sectional images of the body relatively free from superimposition of
the different tissues.
-revolutionized the ability to visualize soft tissues
Principles of CT - Answer--employs x-rays that are attenuated by body tissues. The
radiodensities of the tissues are represented in the image as shades of gray
-creates images based on cross-sectional (axial) slices, created by up to 1000
projections from different angles
Components of CT scanner - Answer-1: the gantry: contains the x ray tube
2:operator's console
3: the computer
The detectors - Answer--x rays are attenuated by body tissues and then exit the pt's
body as remnant radiation, similar to conventional radiography.
-up to 1000 detectors are arranged in an array, encircling the pt, for the purpose of
measuring this remnant radiation
-modern units have 4-16 arrays
Data anquisition system - Answer--amplifies the signal from the detectors
-incoming signal is in the form of a varying electrical current= ANALOG SIGNAL
-system converts it from analog to digital form and then sends it to the computer
Scout image - Answer-2 dimensional digital radiograph-localizes the structures to be
scanned
Pitch - Answer-movement of the tabletop
Represents the ratio of tabletop movement to slice thickness
Volumetric scanning - Answer-large volumes of data with high accuracy and short
imaging times
Not limited to axial plane.
Can be any plane or even 3D, w/out loss of spatial resolution
3D CT - Answer-volumetric scanning
Presentation of body parts can be rotated in "in space" on the computer screen
Process called multiplanar reconstruction (MPR)
