CT 1 Flashcards
Adv of CT over Plain film X-ray
Reduced SuperImposition
Better Contrast
Single Breadth volume scans
Multi planar imaging
DisADV. of CT over Plainf Film X-ray
Lower spatial res
higher dose
more artifacts
Why does CT have a lower spacial res?
Lower FDD
Lower ODD
Typical CT range and values for water, air and bone
-1024 - +3071
Air: -1000
Water: 0
Bone: +1000
Which CT gen introduced fan beam tech?
2nd
Which CT gen introduced 360 rotation AND curved detectors?
3rd
Which CT gen introduced DSCT (dual source CT) and what was it mainly used for scanning?
6th - 2x Xray tubes.
Cardiac CT
Why did 7th Gen have a lower contrast?
Used flat panel detectors over multidetectors
What CT gen is helical scanners based on?
3rd
What technology allows for continuous gantry rotation?
Slip ring
What is Spiral width dependent on?
Patient and X-ray movement speed
What will a wider spiral width cause?
LOWER spatial and contrast res
What beam does a multi-slice CT scanner use?
CONE
Why does a table have a low µ?
A high Z would increase patient does (plus increase noise).
What is the purpose of a bow tie filter?
Counteracts beam hardening by attenuating the beam more at the periphery as opposed to the centre. Resulting in a more ‘uniformed’ beam.
