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Computed tomography questions with correct answers 100%.
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Computed tomography questions withcorrect answers 100%.
CT Vs Radiography ANS - CT forms cross sectional images eliminating the superimposition of structures
that occurs in plane film imaging because of compression of 3D body systems onto the 2D recording
system.
Sensitivity of CT to subtle differences in x-ray attenuation is at least a factor 10 higher than normally
achieved by screen film recording systems because of the virtual elimination of scatter
Radiation exposure ANS - Multiple x-ray images being taken so the amount of radiation exposure is
higher than that of x-rays.
Production of images ANS - Motorised x-ray source which rotates around the bore of the gantry. Couch
moves through the gantry, narrow x-ray beams shot at the body. Within the gantry- x-ray detectors
located directly opposite the source so beams shot directly through the body. Detected beams
transmitted to a computer. After completing a full rotation the computer generates a 2D slice of the
patient and the couch is moved further into the boar. Slices can be stacked together to make a 3D
image.
1970's ANS - CT scanner invented by Godfrey Houndsfield, took several hours to acquire an the raw
data for a single slice and took days to reconstruct a single image. Used existing x-ray technology, first to
combine the x-ray machine with a computer. Could only take pictures of the brain (first scan taken in
1971)
First CT scanner ANS - Single pencil beam configuration, moved one degree for 180 degrees.
Attenuation that occurred was picked up by a single detector. One the beam had passed all the way
through, the objects were rotated one degree and the beams would pass through again. Around 9 days
to obtain a full image- transferred to a supercomputer which would take around 2.5 hours to
reconstruct the image
First generation scanner ANS - Single pencil beam configuration, moved one degree for 180 degrees.
Only for imaging the brain. Around 20 minutes to obtain a full image. Beam went through the brain and
then rotated one degree. Info sent of site to a computer to be reconstructed.
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