Single Detector VS Multidetector CT Scans Flashcards
Milestone of multidetector row CT
increased scan speed
improved z-axis spatial resolution,
better utilization of the available x-ray power
The single-row design was used in
both third- and-fourth generation systems
How many elements that were arranged in an arc in third generation systems
approximately 700 detector elements were arranged in an arc.
Fourth-generation systems used ____ in a single row arranged in a complete ring.
as many as 4,800 detectors
Each detector element is quite wide in the z direction
approximately 15 mm
Slice thickness in single detector ct scans is controlled by
opening or closing of the collimator.
The width of the detector limits
Slice thickness
The largest allowable slice thickness
less than the detector width, typically 10 mm.
The radiation emitted from the collimated x-ray source in these systems is commonly referred to as
fan beam
Each gantry rotation produces data for
a single slice
calculating the area of patient anatomy to be covered
multiply the slice increment selected by the number of slices acquired.
If slices are contiguous the slice increment will be equal to
slice thickness
MULTIDETECTOR ROW SYSTEMS also known as
- Multi-slice CT or MSCT
- Multi-detector CT or MDCT
- Multi-channel CT or MCCT
- Multi-row CT or (MRCT less common as abbreviation)
How many parallel rows of detectors do multidetector row systems have?
4 to 64 parallel rows
MDCT provides
longer and faster z axis coverage per gantry rotation.
What is the scanning slices per year?
1991 - 2 1998 - 4 2002 - 16 2003 - 32 Now - 64 with 0.4s rotation
Slice thickness in multidetector ct scans is determined by
combination of x-ray beam width and the detector configuration
The radiation emitted from the collimated x-ray source in these systems is commonly referred to as
cone beam
Multiple detector channels can be used for
either axial or helical data acquisitions
Depending on the scanner manufacturer and the number of detector rows, the parallel rows may be:
- Uniform array with equal size
- Variable, with thinner rows centrally and wider rows peripherally.
variable-width detector rows are also called
adaptive arrays,
non-uniform arrays, or
hybrid arrays.
used determine the slice thickness and number of slices that can be acquired simultaneously.
size and number of segments
Compared with SDCT, for a given slice thickness
MDCT results in a fourfold increase in the volume of data acquired in a single rotation
the slice thickness of an MDCT scanner is determined by the
degree of physical collimation of the x-ray beam and the width of the detectors in the slice thickness (z axis) dimension.
The width of the slice is changed by
combining different numbers of individual detector elements together.
When combined, the electronic signals generated by adjacent detectors are
summed
currently being used in clinical setting
256-row detectors
256-row scanners have the ability to
image the heart, brain, and many other organs in a single rotation
were responsible for the demise of fourth-generation scanning systems
MDCT designs
To form a complete ring
many separate detector elements were required
In MDCT, how many detectors will be used?
307,200 detectors
