Image-guided adaptive brachytherapy dose escalation for cervix cancer via fractionation compensation
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 tota...
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| Main Authors: | , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
6 February 2017
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| In: |
Brachytherapy
Year: 2017, Volume: 16, Issue: 3, Pages: 534-546 |
| ISSN: | 1873-1449 |
| DOI: | 10.1016/j.brachy.2017.01.002 |
| Online Access: | Verlag, Volltext: http://dx.doi.org/10.1016/j.brachy.2017.01.002 Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S1538472117300053 
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| Author Notes: | William Shaw, William I.D. Rae, Markus L. Alber |
| Summary: | 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 patients 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 organs at risk (OARs) 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 patient population. However, a subgroup of patients with alternating dose-limiting OARs 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 tumor doses, although slightly lower OAR doses. By distributing the treatment aim over an increased number of treatment fractions, median tumor 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 patients with alternating dose-limiting OARs and is enhanced using more treatment fractions and EUD constraints. |
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| Item Description: | Available online 6 February 2017 Gesehen am 01.08.2018 |
| Physical Description: | Online Resource |
| ISSN: | 1873-1449 |
| DOI: | 10.1016/j.brachy.2017.01.002 |