PURPOSE: In image-guided adaptive brachytherapy (IGABT), dose distributions are optimized for each fraction. Optimum fractional dose can be constant or adapted to previous fractions and a conjecture about the future ones. We evaluate the efficacy of different fraction size schemes, derived from total IGABT dose constraints, against constant per-fraction constraints. METHODS AND MATERIALS: This retrospective planning study included 20 IGABT @entity1 where four different fractionation schedules were compared based on modern planning recommendations. A total high-risk-clinical target volume D90 (minimum dose in 90% of the volume) dose aim of 90.0  Gy with constant per-fraction @entity347 ( @entity347 ) dose constraint planning (CONST) was compared with conservative and aggressive fractionation compensation (COMP) techniques. COMP allows variations in the per-fraction dose constraints. Dose accumulation was performed through dose summation at a given volume and equivalent uniform dose (EUD) worst-case dose estimates. RESULTS: No significant differences were identifiable between dose metrics of CONST and COMP in the total @entity1 population. However, a subgroup of @entity1 with alternating dose-limiting @entity347 had significant benefit from COMP. Median high-risk-clinical target volume dose escalation ranged from 5% to 12%, whereas OAR dose increases were lower and ranged from 3% to 8%. EUD-based planning delivered similar @entity5 doses, although slightly lower OAR doses. By distributing the treatment aim over an increased number of treatment fractions, median @entity5 dose could be increased by a further 8% per additional treatment fraction at the same OAR dose levels for both CONST and COMP. CONCLUSIONS: COMP is effective in @entity1 with alternating dose-limiting @entity347 and is enhanced using more treatment fractions and EUD constraints.

Image-guided adaptive brachytherapy dose escalation for cervix XXXX via fractionation compensation.

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor'] @entity347 :: ('MESH:D019965', 'Disease') :: ['organs at risk', 'OARs']
@entity5 :: (MESH:D009369,Disease) :: ['cancer']
