Basic Clinical Radiobiology 2017

Concept of Functional Sub-Units (FSUs)

lung liver kidney

spinal cord esopha- gus intestine

parallel organisation

 Inactivation of one subunit can lead to loss of organ function (binary response) risk of complication strongly influenced by “hot spots” serial organisation

 functional damage, if a critical number of FSU’s is inactivated (threshold volume) risk of complication ~ total dose distribution rather than on “hot spots”

ESTRO BCR Course / Volume effect in RT – W. Dörr