32. CT: MULTI SLICE CT Flashcards
1
Q
- What happens when we increase the number of Detector Rows?
A
- multiple channels of data can be acquired
simultaneously - this is known as a Multi Detector CT
- or a Multi-Slice CT
2
Q
- What is the advantage of a Multi-Slice CT?
A
- there is increased longitudinal coverage
- this benefits the data acquisition
- this is achieved per rotation
3
Q
- Why are Multi-Slice CTs and their increased longitudinal coverage particularly useful for?
A
- Cardiac data acquisitions
- these deal with longer scan times
- they image non-moving organs
4
Q
- What does the current state-of-the-art CT technology simultaneously acquire?
A
- it acquires 320 slices
- this costs about 2.5 million dollars
5
Q
- How many rows are 320-slice scanners physically equipped with?
A
- 320 detector rows
6
Q
- List 5 types of CT detector Systems?
A
- 16-slice scanners
- 32- slice scanners
- 64- slice scanners
- 128-slice scanners
- 256-slice scanners
MOST CLINICS AND HOSPITALS USE:
- 128 and 256 slice scanners
- the 320 ones are too expensive
7
Q
- How can some systems allow for twice their slice acquisition?
A
- they double sample
- they do this in a longitudinal direction
8
Q
- What happens when we have a rapid, longitudinal alteration of the focal spot during acquisition?
A
- we will acquire two partially overlapping sets of
projections - they each come from slightly different positions
9
Q
- What can be said about systems with single sampling, vs systems with double sampling?
A
UNLIKE SINGLE SAMPLING SYSTEMS:
- double sampling will result in an improved
longitudinal resolution
- it will also have a longer total scan time
10
Q
- What does an expansion in the number of detectors result in?
A
- the individual width of each detector will decrease
- this is because the area of the ring where the detectors
are positioned is constant
11
Q
- How does the individual detector width change from a 4 to a 64 Slice CT detector?
A
4 SLICE DETECTOR:
- its between 1.0 - 1.25 mm
64 SLICE DETECTOR:
- it decreases to 0.4 - 0.5 mm
12
Q
- What improves the Spatial Resolution in the Longitudinal Direction?
A
- the increase in the number of detectors
- the overlapping reconstruction of the slices
13
Q
- What increases the coverage of the Multi-Slice CT scanner?
A
- the more active detector rows that become available
14
Q
- What is the Dual Source CT Scanner?
A
- it is a CT scanner that is equipped with two X-Ray tubes
- we have two detectors
- these rotate at a 90° angle to each other (⟂)
15
Q
- What is the advantage of the Dual Source CT scanner?
A
- the improvement of the Temporal Resolution
18
Q
- Does this table of advances make sense?
A
- yes
