Tomography creates images of internal structures by imaging sections through an object. This lesson introduces the basic vocabulary of tomography, explains how projection measurements are reconstructed into tomograms, and compares two major reconstruction approaches.
Tomography is imaging by sections, or sectioning, using penetrating waves. Instead of representing all structures superimposed in a single projection, tomographic methods aim to reveal information about internal sections or volumes.
All flashcards
What does tomography mean?
Tomography is imaging by sections or sectioning using penetrating waves, allowing internal structure to be examined rather than represented only as a superimposed projection.
How do tomograph and tomogram differ?
A tomograph is the device used in tomography; a tomogram is the image it produces.
What is tomographic reconstruction?
It is the mathematical process of estimating an internal image from tomographic measurement data, such as multiple projections.
How do FBP and IR differ in their usual trade-offs?
Filtered back projection generally uses fewer computational resources. Iterative reconstruction generally produces fewer artifacts, but has a higher computational cost.
How does MRI acquire spatial information without moving parts?
MRI applies spatially varying magnetic fields to sample projections and higher spatial harmonics, so moving parts are not needed to generate an image.
Quiz questions
In tomography, what is a tomogram?Answer: An image showing internal sections reconstructed from measurements.
What does a voxel represent in a regularly sampled three-dimensional data set?Answer: A volume element carrying a sampled data value.
What produces synchrotron radiation when charged particles follow a curved path?Answer: Their changing direction causes radial acceleration and radiation emission.
How did focal plane tomography make a selected plane appear sharper?Answer: The X-ray source and film moved in opposite directions during exposure.
How can MRI encode spatial information without moving imaging parts?Answer: Spatially varying magnetic fields encode projections and higher spatial harmonics.
Based on the Wikipedia article Tomography, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.