In-vivo treatment accuracy analysis of active motion-compensated liver SBRT through registration of plan dose to post-therapeutic MRI-morphologic alterations
Background/purpose - In-vivo-accuracy analysis (IVA) of dose-delivery with active motion-management (gating/tracking) was performed based on registration of post-radiotherapeutic MRI-morphologic-alterations (MMA) to the corresponding dose-distributions of gantry-based/robotic SBRT-plans. - Methods -...
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| Main Authors: | , , , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
15 February 2019
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| In: |
Radiotherapy and oncology
Year: 2019, Volume: 134, Pages: 158-165 |
| ISSN: | 1879-0887 |
| DOI: | 10.1016/j.radonc.2019.01.023 |
| Online Access: | Verlag, Volltext: https://doi.org/10.1016/j.radonc.2019.01.023 Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S0167814019300283 
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| Author Notes: | Judit Boda-Heggemann, Anika Jahnke, Mark K. H. Chan, Floris Ernst, Ardekani Leila Ghaderi, Ulrike Attenberger, Peter Hunold, Jost Philipp Schäfer, Stefan Wurster, Dirk Rades, Guido Hildebrandt, Frank Lohr, Jürgen Dunst, Frederik Wenz, Oliver Blanck |
| Summary: | Background/purpose - In-vivo-accuracy analysis (IVA) of dose-delivery with active motion-management (gating/tracking) was performed based on registration of post-radiotherapeutic MRI-morphologic-alterations (MMA) to the corresponding dose-distributions of gantry-based/robotic SBRT-plans. - Methods - Forty targets in two patient cohorts were evaluated: (1) gantry-based SBRT (deep-inspiratory breath-hold-gating; GS) and (2) robotic SBRT (online fiducial-tracking; RS). The planning-CT was deformably registered to the first post-treatment contrast-enhanced T1-weighted MRI. An isodose-structure cropped to the liver (ISL) and corresponding to the contoured MMA was created. Structure and statistical analysis regarding volumes, surface-distance, conformity metrics and center-of-mass-differences (CoMD) was performed. - Results - Liver volume-reduction was −43.1±148.2cc post-RS and −55.8±174.3cc post-GS. The mean surface-distance between MMA and ISL was 2.3±0.8mm (RS) and 2.8±1.1mm (GS). ISL and MMA volumes diverged by 5.1±23.3cc (RS) and 16.5±34.1cc (GS); the median conformity index of both structures was 0.83 (RS) and 0.80 (GS). The average relative directional errors were ≤0.7mm (RS) and ≤0.3mm (GS); the median absolute 3D-CoMD was 3.8mm (RS) and 4.2mm (GS) without statistically significant differences between the two techniques. Factors influencing the IVA included GTV and PTV (p=0.041 and p=0.020). Four local relapses occurred without correlation to IVA. - Conclusions - For the first time a method for IVA was presented, which can serve as a benchmarking-tool for other treatment techniques. Both techniques have shown median deviations <5mm of planned dose and MMA. However, IVA also revealed treatments with errors ≥5mm, suggesting a necessity for patient-specific safety-margins. Nevertheless, the treatment accuracy of well-performed active motion-compensated liver SBRT seems not to be a driving factor for local treatment failure. |
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| Item Description: | Gesehen am 13.05.2019 |
| Physical Description: | Online Resource |
| ISSN: | 1879-0887 |
| DOI: | 10.1016/j.radonc.2019.01.023 |