Physics of Computed Tomography

What are X-rays and when were they discovered?

How do X-ray images represent different tissues?

What is a CT scan and how does it differ from traditional X-rays?

What are projected rays in the context of CT scanning?

What does radiation attenuation refer to?

What is meant by energy dependent in X-ray imaging?

What are CT numbers (Hounsfield Units or HU)?

What is the importance of accuracy in CT numbers?

What factors can affect the accuracy of CT numbers?

• Scanner calibration errors

• Beam hardening

• Patient movement during scanning

• Artifacts from metallic implants

What does uniformity of CT numbers refer to?

• Consistency of CT numbers across different areas

• Variability of CT numbers in different tissues

• The accuracy of CT numbers

• The calibration of CT machines