Advanced Skills in Modern Radiotherapy 2018

CT numbers = Hounsfield units

The grey tones on the CT image represent the attenuation in every pixel/voxel

The grey tones are expressed in Hounsfield units (HU) – CT numbers:

μ

– μ

obj water HU = –––––––– x 1000 μ water

Luft ~ -1000 HU Vand ~0 HU Knogler >1000 HU