PIII: Basics of CT

Scatter

As much as 90% of image may come from scatter

Tomography provides an _______ tomogram

axial

Overlying structures obscure ________ pathology

underlying

Scatter is partially overcome by tomograms _________ and ____ ___________ of structures in focal plane improved

Contrast, edge enhancement

CT provides a _________ image

Transverse

The 3 Primary components of a CT scanner

1. Computer

2. Gantry & Table 

3. Operator’s console 

CT: Computer

• control image data acquisition

• image reconstruction

• storage of image

• image display

CT: Gantry/Table

• x-ray tube

• detector array

• scintillation (solid state)

• ionization (xenon gas)

CT: Operator’s Console

• displays images in shades of gray

• allows image pre and post processing

• Window level

• Window width

CT scanner components