Introduction to CT

Why CT?

• Conventional radiography (CR), AKA x-rays, is a 2D representation of a 3D structure​

• Limitations​

  • Overlapping structures can obscure (e.g. skull obscures brain)​

  • CR images are a representation of density, although differentiation between similar densities is poor (e.g. soft tissue versus water)

What is CT?

• Computed tomography (CT) uses rotating x-rays to create a cross sectional image slice​

• Sequential slices are obtained as the patient moves through the gantry (circular opening of the CT)​

• CT allows for rapid image acquisition in seconds, but requires higher radiation