Diagnostic- Computed Tomography
questions with verified answers.
_____ imaging modality that creates cross sectional images of the body using x-rays ANS - CT
______ credited with the invention of CT ANS - Godfrey Hounsfield
Give the year
1_______ - Godfrey Hounsfield first successful demonstration of CT scans
2________-CT becomes widely available
3________- spiral CT introduced
4________-multislice introduced
5________-company produces scanner fast enough to scan heartbeat (called electronic beam CT) ANS -
1. 1970s
2. 1980s
3. 1990s
4. 2000s
5. 2008
Why are electronic beam CT scanners not used, even though they are the fastest scanners able to image
heartbeats? ANS - exceedingly high rad dose to patient
Categorize CT scanners by generation:
Gen 1: __________
Gen 2: __________
Gen 3:__________
Gen 4:__________ ANS - Gen 1: pencil beam (single detector)
Gen 2: multiple pencil beams (multiple detectors)
, Gen 3: fan beam (with moving detector array)
Gen 4: stationary ring of detectors, tube moves in full revolution (w slip-ring technology)
First CT scanners were dedicated to _______ ANS - head scanners
______-pencil-thin beam of radiation that strikes a single detector ANS - ray
A _______ is composed of a set of rays striking a detector array ANS - projection/view
classifies CT scanners ANS - number of detectors/slices
CT is used for:
(Give examples) ANS - Trauma, Interventional, Nuclear Med (PET scans), and Routine exams
______ is a grid of rows and columns used to gather image data for CT scanners; made up of ______,
aka picture elements ANS - matrix; pixels
3D volume element ANS - voxel
Unlike CR and DR in x-ray, there is not a ________ used in CT to measure exposure ANS - exposure
index
Instead of using an exposure index, CT uses _______ assigned to each pixel ANS - Hounsfield Unit
In CT, _______ are numbers assigned to pixels based on the different attenuation coefficients of
materials; directly proportional to signal strength. It is based on water as a reference ANS - Hounsfield
Units
HUs are based on ______ as a reference, with a HU of _____; chosen because it is widely available in the
body and has a uniform density ANS - water; HU of 0
questions with verified answers.
_____ imaging modality that creates cross sectional images of the body using x-rays ANS - CT
______ credited with the invention of CT ANS - Godfrey Hounsfield
Give the year
1_______ - Godfrey Hounsfield first successful demonstration of CT scans
2________-CT becomes widely available
3________- spiral CT introduced
4________-multislice introduced
5________-company produces scanner fast enough to scan heartbeat (called electronic beam CT) ANS -
1. 1970s
2. 1980s
3. 1990s
4. 2000s
5. 2008
Why are electronic beam CT scanners not used, even though they are the fastest scanners able to image
heartbeats? ANS - exceedingly high rad dose to patient
Categorize CT scanners by generation:
Gen 1: __________
Gen 2: __________
Gen 3:__________
Gen 4:__________ ANS - Gen 1: pencil beam (single detector)
Gen 2: multiple pencil beams (multiple detectors)
, Gen 3: fan beam (with moving detector array)
Gen 4: stationary ring of detectors, tube moves in full revolution (w slip-ring technology)
First CT scanners were dedicated to _______ ANS - head scanners
______-pencil-thin beam of radiation that strikes a single detector ANS - ray
A _______ is composed of a set of rays striking a detector array ANS - projection/view
classifies CT scanners ANS - number of detectors/slices
CT is used for:
(Give examples) ANS - Trauma, Interventional, Nuclear Med (PET scans), and Routine exams
______ is a grid of rows and columns used to gather image data for CT scanners; made up of ______,
aka picture elements ANS - matrix; pixels
3D volume element ANS - voxel
Unlike CR and DR in x-ray, there is not a ________ used in CT to measure exposure ANS - exposure
index
Instead of using an exposure index, CT uses _______ assigned to each pixel ANS - Hounsfield Unit
In CT, _______ are numbers assigned to pixels based on the different attenuation coefficients of
materials; directly proportional to signal strength. It is based on water as a reference ANS - Hounsfield
Units
HUs are based on ______ as a reference, with a HU of _____; chosen because it is widely available in the
body and has a uniform density ANS - water; HU of 0
