Biomedical Engineering Reference
In-Depth Information
Figure 3.1. ICRU definitions for: (a) tumor-related volumes, and (b) normal
tissue-related volumes. Reproduced (in redrawn form) with permission
from ICRU78 (2007).
Normal tissue-related terms
Figure 3.1b shows schematically the terms associated with normal
tissue definition. They are:
organ at risk
OAR
any organ or compartment of
normal tissue which might be
significantly impacted by the
radiation dose delivered
planning risk volume
PRV
the volume encompassing an
OAR
plus
a margin (IM) for
expected physiological
movements and temporal
variations in size, shape and
position of the OAR, and
plus
a margin (SM) for
uncertainties in patient
positioning and alignment of
the therapeutic beams
