Computed Tomography Science Flashcards
7 cards from real Computed Tomography Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Computed Tomography Science flashcards as text
Which term describes the ability of a CT system to distinguish between two objects with very similar attenuation values?
Answer: Low-contrast resolution
Low-contrast resolution (contrast resolution) measures the system's ability to differentiate objects with nearly identical attenuation coefficients.
In CT, the process of reconstructing an image from projection data using mathematical algorithms is called:
Answer: Filtered back-projection
Filtered back-projection (FBP) applies a convolution filter to raw projection data before back-projecting it to form the image.
The Hounsfield unit (HU) value of cortical bone is approximately:
Answer: +1000 HU
Cortical bone typically measures around +1000 HU on the Hounsfield scale, with water at 0 HU and air at -1000 HU.
Which detector configuration in multi-detector CT (MDCT) acquires data simultaneously from multiple rows, allowing faster volume coverage?
Answer: Multi-row detector array
Multi-row detector arrays allow simultaneous acquisition of multiple slices per gantry rotation, dramatically increasing volume coverage speed.
What effect does increasing the pitch in helical CT have on patient dose?
Answer: Decreases dose by reducing overlap
Increasing pitch means the table moves faster per rotation, resulting in less beam overlap and a reduced effective dose to the patient.
The term 'isotropic voxel' in CT means the voxel dimensions are:
Answer: Equal in all three dimensions
Isotropic voxels have equal x, y, and z dimensions, enabling high-quality multiplanar reformations in any orientation.
Which artifact appears as a dark band between two high-density objects in CT images?
Answer: Beam hardening artifact
Beam hardening causes dark streaks or bands between dense structures because lower-energy photons are preferentially absorbed, shifting the beam spectrum.