Physics Athens 2016

Conversion of m to CT number

m values are scaled to that of water to give the CT number (Hounsfield Unit)

Tissue

CT-number (HU)

Air

-1000

Lung

-300

Fat

-90

m m

- m - m

tissue

water

CT number = 1000 x

Water

0

water

air

White Matter Gray Matter

30 40

TPS: The relative electron density of the irradiated medium can be determined from the CT data set via the conversion between CT numbers and r e

Muscle 50 Trabecular Bone 300-500 Cortical Bone 600 -3000