2. First Generation Scanners
Single detector, single x-ray tube,
rotate/translate pencil beam system,
rotation angle/step 1°
Long scan time
Poor spatial resolution
Best scatter rejection
7. Second Generation Scanners
Linear array of about
30 detectors, single x-
ray tube,
rotate/translate
motion, narrow angle
(10 ° ) fan beam
rotation angle/step 10°
Shortest scan time
was about 18 s per
slice
8. Third Generation Scanners
Linear array of about
800 detectors, single x-
ray tube, rotate/rotate
motion only, wide fan
beam to cover the
entire patient
Scan time of newer
scanners is about ½ s
per slice
Can produce ring
artifacts
9. Fourth Generation Scanners
Complete circular array of
about 4800 stationary
detectors
Single x-ray tube rotates
with in the circular array of
detectors
Wide fan beam to cover
the entire patient
Scan time of newer
scanners is about ½ s per
slice
Designed to address ring
artifacts
10. Fifth Generation Scanners
210° arc array of stationary detectors
x-rays are produced from the focal track
as high energy electron beam strikes the
tungsten target
Scan time is about 50 ms per slice
Developed for cardiac tomographic
imaging