ct 3  Created by flashcardasdf   Remove ads  70 terms  In 1972,
the EMI scanner was the  first CT scanner introduced into
clinical practice.  - EMI scanners used a  pencil beam and
sodium iodide (NaI) detectors that moved across the patient
(Le., translated) to obtain one projection data set.  -The x-ray
tube and detector were  rotated 1 degree, and another projection
was obtained (rotation).  -The EMI scanner thus used a
translate/rotate acquisition geometry, which is known as a
first-generation system.  - The CT scanner generation defines
the  acquisition geometry.  -An old generation is not
(necessarily)   -Second-generation scanners also use translate-
rotate technology but have  multiple detectors and a fan-shaped
beam.  -Third-generation scanners use a wide rotating fan beam
coupled with a  large array of detectors (rotate-rotate system).
-The geometric relationship between the tube and detectors does
not change as it  rotates 360 degrees around the patient.
-Fourth-generation scanners have a  rotatin