Image Reconstruction and Interpolation in Helical CT

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Questions and Answers

What is the main purpose of interpolation algorithms in helical CT scans?

To reconstruct axial images from the spiral volume data set (correct)
To reduce motion artifacts
To enhance 3D renderings
To increase the speed of the scan

What is the definition of pitch in helical CT scans?

The speed of the table motion during the scan
The ratio of table displacement per 360° rotation to section thickness (correct)
The width of the x-ray beam
The overlap between consecutive helical loops

What happens when the pitch is less than 1 in a helical CT scan?

The patient dose is reduced
There is a gap between the x-ray beam edge of the consecutive loops
The coils of the helix overlap (correct)
The x-ray beam associated with consecutive helical loops is contiguous

What is the main advantage of a helical CT scanner compared to a conventional CT scanner?

All of the above (D) Signup and view all the answers

What happens when the pitch is greater than 1 in a helical CT scan?

There is a gap between the x-ray beam edge of the consecutive loops (D) Signup and view all the answers

What is the relationship between pitch and table travel per rotation in helical CT scans?

Pitch = table travel / beam width (B) Signup and view all the answers

What is the mathematical process that allows reconstruction of an image at any z-axis position?

Interpolation (D) Signup and view all the answers

What is the primary challenge faced by conventional reconstruction algorithms when dealing with helical CT data?

The X-ray source travels in a helical trajectory around the patient. (C) Signup and view all the answers

What is the purpose of the interpolation algorithm in helical CT scanning?

To convert the helical data set into a series of planar image data sets. (B) Signup and view all the answers

Why is data interpolation necessary during helical CT image reconstruction?

The image plane does not contain enough data for direct reconstruction. (D) Signup and view all the answers

What is the result of the interpolation process in helical CT scanning?

A series of planar image data sets in the reconstruction plane of interest. (B) Signup and view all the answers

What is the difference between interpolation and extrapolation?

Interpolation estimates values between known data points, while extrapolation estimates values beyond the range of known data points. (A) Signup and view all the answers