Lecture #1: Understanding CT Scanner Components and Physics

A set of QUESTION_AND_ANSWER flashcards covering CT scanner components, physics basics, advanced technologies, image formation, optimization, artifacts, and CT vs X-ray concepts.

What does CT stand for and what is a key advantage of CT imaging over traditional X-ray?

Computed Tomography; provides 3D cross-sectional images with higher contrast resolution and quantitative assessments.

Which CT component generates high-energy X-ray beams used to scan the body?

X-ray Tube.

What is the purpose of Bowtie filters in CT scanning?

Shape and harden the beam to reduce scatter and enhance contrast.

What is the function of column meters in a CT system?

Measure real-time radiation intensity and help guide the dose delivered to the patient.

What do CT radiation detectors do and what is their basic working principle?

Detect X-rays; scintillators convert X-rays to light, which is converted to electrical signals for image formation.

Which material is typically used for the X-ray tube anode and why?

Tungsten; high atomic number and high melting point, efficiently produces X-rays and tolerates high heat.

What defines beam width and shape in CT imaging?

Collimation and beam control.

How do Bowtie filters affect dose distribution?

They help equalize beam intensity across the patient, reducing dose variation and improving uniformity.

What does Multi-Detector CT (MDCT) enable?

Captures multiple slices per gantry rotation; enables high-speed imaging and 3D volume rendering.

What does Dual-Source CT (DSCT) involve and what are its benefits?

Two X-ray sources and detectors; allows dual-energy scanning, faster acquisitions, and reduced motion artifacts and dose.

Name two common reconstruction algorithms used in CT image formation.

Filtered back projection and iterative reconstruction.

What controls the grayscale display in CT and what scale is used?

Window Width and Window Level control the grayscale display of Hounsfield Units.

How does pixel size affect spatial resolution in CT?

Smaller pixel size yields higher spatial resolution.

Define Pitch in CT scanning and its formula.

Pitch = table movement per rotation / slice thickness; affects scan time and radiation dose.

Which contrast agent is commonly used in CT to enhance soft tissues and vessels?

Iodinated contrast; improves visualization in angiography, cardiac imaging, and CT fluoroscopy.

List common artifacts seen in CT imaging.

Motion artifacts, beam hardening, metal streaks, and partial volume averaging.

How can you manage trade-offs between resolution, contrast, and radiation dose in CT?

Adjust slice thickness, pitch, exposure time, and filters.

What is the main difference between CT imaging and conventional X-ray imaging in terms of output?

CT provides 3D cross-sectional images; X-ray provides 2D projection images.