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How accurate are CT numbers…?
• HU of homogeneous material
can vary by 1-2%
• Depends on location (beam
hardening) – up to 3%
• Variation across scanners for
high density (>5% in cases)
• Electron Density of Tissue
Substitutes
• Tissue substitutes=tissues?
• Tissue Assignment (ICRU and
ICRP)?
M. Schwarz