13 Questions
What is another name for Computed Tomography (CT)?
Computerized tomography
How does Computed Tomography (CT) create images of the body?
By taking detailed x-ray scans
Why is radiography limited in its ability to distinguish certain structures?
Because it can only provide qualitative information
What distinguishes Computed Tomography (CT) from radiography?
CT produces cross-sectional images, while radiography produces 2D images
What is the major shortcoming of radiography mentioned in the text?
Superimposition of structures on the film
How does Conventional Tomography overcome the problem of superimposition in radiography?
By capturing images at different angles
What is the immediate goal of tomography?
To eliminate structures above and below the focused section
Why do radiography and tomography fail to adequately demonstrate slight differences in subject contrast?
Film-screen combinations can only discriminate x-ray intensity differences of 5% to 10%
What significant way does CT differ from conventional radiography?
CT forms cross-sectional images eliminating superimposition of structures
What is a significant advantage of CT over conventional radiography in terms of sensitivity to x-ray attenuation differences?
CT has at least 10 times higher sensitivity
How does the circular opening in a CT scanner play a role in patient imaging?
It houses a patient couch where the patient lies during scanning
What is the purpose of digital geometry processing in CT scans?
To generate three-dimensional images from two-dimensional X-ray images
What does the scanner gantry in a CT scanner contain?
The rotating portion that holds the X-ray tube generator and detector array
Study Notes
Computed Tomography (CT)
- CT is an imaging procedure that uses special x-ray equipment to create detailed pictures of areas inside the body.
- Also known as computerized tomography or computerized axial tomography (CAT).
Characteristics of CT
- Noninvasive
- Produces cross-sectional images of the body
- Each cross-sectional image represents a “slice” of the person being imaged
- Used for diagnostic and therapeutic purposes
Limitations of Radiography and Conventional Tomography
- Superimposition of all structures on the film, making it difficult to distinguish details
- Qualitative rather than quantitative process
- Distinguishing between homogeneous objects of nonuniform thickness and heterogeneous objects is difficult
- Conventional tomography limitations: image blurring, degradation of image contrast, and other problems
Advantages of CT over Radiography and Tomography
- Can eliminate superimposition of structures
- Highly sensitive to subtle differences in x-ray attenuation
- Can alter contrast to suit the needs of the human observer using digital image postprocessing techniques
CT Scan Applications
- Can be performed on every region of the body
- Used for diagnostic, treatment planning, interventional, or screening purposes
- Can generate three-dimensional images
- Used in nondestructive materials testing, biological and paleontological specimens, and medicine
CT Scan Purpose
- Provides detailed cross-sectional images of internal structures (e.g., organs, blood vessels, bones, soft tissue)
- Used for diagnostic purposes, guidance for specific treatment or further tests, and detection and monitoring of conditions (e.g., cancer, heart disease, lung nodules, liver masses)
CT Scan Technique
- Digital geometry processing generates a three-dimensional image from a series of two-dimensional X-ray images
- Patient lies flat on a table that moves into the gantry
- X-ray tube rotates around the patient, and detectors acquire measurements that are then calculated into a viewable image
- One cross-sectional slice of the body is obtained for each complete rotation
Test your knowledge about computed tomography (CT) imaging with this quiz. Learn about how CT scans create detailed cross-sectional images of the body using special x-ray equipment.
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