The CT number or Hounsfield unit represents:
A. the sum of the voxel attenuation along the radiation path.
B. the attenuation coefficient number.
C. the amount of X-ray radiation emitted.
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X-ray attenuation depends on:
A. the µ value.
B. the density of tissue.
C. the quantity of detectors.
A calibrated scaling factor is calculated to scale the CT attenuation map because:
A. a) the images need to be aligned.
B. b) PET gamma rays have higher energy than CT X-rays.
C. c) PET gamma rays have lower energy than CT X-rays.
There is a greater chance of the PET signal being attenuated when:
A. a) the object being imaged is smaller.
B. b) the object being imaged is larger.
C. c) the object is further away from the detector.
PET reconstruction is:
A. a) deterministic.
B. b) performed via a Fourier transformation.
C. c) probabilistic.
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