PhysicsChapter 11: Medical Imaging
Why Ct Beats A Plain X-Ray Film
CT can provide more detailed localization and cross-sectional information than a plain X-ray because it reconstructs tissue information from
Definition
CT can provide more detailed localization and cross-sectional information than a plain X-ray because it reconstructs tissue information from many projections rather than displaying all structures superimposed in one projection.
Plain X-ray
A plain radiograph is a two-dimensional projection. Structures at different depths can overlap. This **superposition** can hide details.
CT
CT collects projections from many directions. Computer reconstruction separates information spatially into slices. This provides: better localization; cross-sectional views; improved distinction between many tissues; reduced structural overlap; * ability to combine slices for 3D representations.
Important Trade-off
CT commonly involves a **higher ionising-radiation exposure** than a single simple radiograph, depending on the examination and protocol. Therefore, its benefits must be balanced against radiation exposure.
Formula / Key Relation
Plain X-ray: **3D structures → one 2D projection CT: many projections → reconstructed slices**
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Review the key facts, formulas and checks before you move on.Why Ct Beats A Plain X-Ray Film
Sticky Notes · Quick Revision
X-RAY vs CT
- X-ray → 2D projection
- CT → cross-sectional slices
- CT detail ↑
- Structural overlap ↓
60-second revision
- CT reduces superposition and improves localization.
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