Computed Tomography Exam
When was CT first demonstrated? By who? Where?
1970 England by Dr. Godfrey Hounsfield and Allen Macleod Cormack
(Not necessary to know, but they both received the Nobel prize in 1979)
Where was the first CT scanner installed? When? Where? *Know that this CT scanner
could only do brain scans.
Atkinson Morley's Hospital in London in 1971
When was the first whole body scanner developed? By who?
in 1974 by Dr. Robert Ledley at Georgetown University Medical Center in Washington,
DC
The first brain scan utilizing CAT scanner took several .... to acquire the data and
several .... to produce the images?
Several hours and several days
What is the definition/Greek meaning of the word "tomography"?
Tomography = from the Greek word "tomos" meaning "section"
*Think of slicing the patient's body like a loaf of bread
The "thickness" of the slice is controlled by ...
the technologist via settings they choose
CT images are created when...
a collimated x-ray beam strikes an image receptor called a detector
What are volume scanners?
Slip rings replaced the high-tension cables of previous CT x-ray tubes. That meant that
these 3rd or 4th generations of CT scanners were able to obtain data continually as the
patient moved continually through the scanner, also known as volume scanning.
What are multislice CT scanners?
3rd and 4th generation scanners were able to image 4 slices simultaneously
What are the advantages to multislice CT scanners? The 1 disadvantage?
Advantages: Short acquisition time, decreased use of contrast media, improved spatial
resolution, improved image quality.
Disadvantage: Increased cost.
What are the 3 major system components of a CT Scanner?
Gantry, Computer, and Operator Console
What is the gantry component of CT?
Circular device that houses the tube and detector array; has the ability to angle up to 30
degrees each direction to better align with anatomy
What does the gantry consist of?
X-ray tube, the detector array, and the collimators (control slice thickness)
What is the opening of the gantry called?
Aperture
What is the X-ray tube designed for?
For increased heat capacity to withstand increased exposure times.
