IMRT

Tissue architecture (2)

Withers et al, IJROBP, 1988

 FSUs in an organ can be organized in ’series’ or in ’parallel’

 The dose-volume behaviour can be thought of as a mixture of two ’extreme’ situations of cell organization patterns  From a mechanistic point of view the probability of a complication depends on the cell killing in FSU, on the organization of the FSUs and on how they carry out the function of the organ