CT REVIEW

What is the first image often obtained in CT scanning?

Scanogram localization image.

What is a matrix in the context of CT imaging?

An array of numbers arranged in a grid made up of rows and columns.

Why is it important to become familiar with CT?

To educate patients, be well-rounded, and become more knowledgeable about the modality.

What are WW and WL in CT imaging?

They define the differences in CT image display.

What can cause CT image artifacts?

Patient motion, metal objects, and pixel size and shape.

What are the advantages of multi-slice CT scanners?

They reduce patient motion artifacts and misregistration.

How has multi-slice technology impacted CT Angiography (CTA)?

It has made CTA routine due to faster scan speeds and thinner slices.

What is the purpose of contrast in CT scans?

To visualize vascular structures.

What did first generation CT scanners scan?

Only the head.

What are Hounsfield Units?

Numeric coefficients used to quantify tissue density.

What is the advantage of Helical/Spiral Scanning?

It results in shorter total scan time.

What was the purpose of Conventional Tomography?

To blur out unwanted structural information and improve image contrast on wanted structures.

What is the main source of radiation exposure to others in the CT scanning room?

Scatter from the patient.

How does spatial resolution relate to pixel size in CT imaging?

Spatial resolution decreases as pixel size increases.

What material is the CT Table typically made of?

Carbon graphite fiber to decrease beam attenuation.

What are the duties of a CT technologist at the operator's console?

To enter information and patient input and view the images.

What are the Hounsfield Units (HU) for average bone, water, and air?

Bone = +1000, water = 0, air = -1000.

What is the aperture or bore in a CT scanner?

The circular opening in the gantry.

What is the fifth generation CT scanner called?

EBCT (Electron Beam Computed Tomography).

What does the gantry house in a CT scanner?

Collimators, x-ray tube, detector, and high-voltage generator.

Who is considered the father of the first CT scanner?

Hounsfield.

How does a metal artifact appear in CT images?

As a 'star'.

How does radiation exposure from CT images compare to diagnostic images?

CT images deliver more radiation to the patient overall.

What is unique about the fourth generation CT scanner?

The x-ray tube rotates while the detectors remain stationary.