This lesson introduces computed tomography (CT), explains how it creates cross-sectional images, and outlines the people and technology involved.
A computed tomography scan, or CT scan, is a medical imaging technique that produces detailed images of structures inside the body. Conventional X-rays project three-dimensional anatomy onto a two-dimensional image, so structures can overlap. CT instead collects many X-ray measurements from different angles and uses a computer to create cross-sectional images, often called slices.
All flashcards
What is computed tomography?
Computed tomography is an imaging technique that uses X-ray measurements collected at multiple angles and computer reconstruction to create cross-sectional images of an object or body.
What does the gantry contain?
The gantry houses the rotating X-ray tube and the detector system positioned to measure X-rays after they pass through the patient.
What is a sinogram?
A sinogram is a visual representation of raw CT projection measurements. Reconstruction algorithms use the data to create images.
How are pixels and voxels different?
A pixel is a two-dimensional image element. A voxel is a three-dimensional volume element that also accounts for the thickness of the CT slice.
Who received the 1979 Nobel Prize for computer-assisted tomography?
Godfrey Hounsfield and Allan MacLeod Cormack jointly received the 1979 Nobel Prize in Physiology or Medicine for the development of computer-assisted tomography.
Quiz questions
What do detectors in a CT scanner measure?Answer: X-rays that pass through the patient
Which statement correctly distinguishes a voxel from a pixel?Answer: A voxel is three-dimensional; a pixel is two-dimensional.
Approximately what Hounsfield value is assigned to water?Answer: 0 HU
How does a dual-source CT scanner improve temporal resolution?Answer: It can acquire a complete slice in half a rotation.
What is a key purpose of dual-energy CT?Answer: Comparing attenuation at two energies to help distinguish materials
Based on the Wikipedia article CT scan, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.