Treating locally advanced lung cancer with a 1.5T MR-Linac - Effects of the magnetic field and irradiation geometry on conventionally fractionated and isotoxic dose-escalated radiotherapy.
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Embargo End Date
ICR Authors
Authors
Bainbridge, HE
Menten, MJ
Fast, MF
Nill, S
Oelfke, U
McDonald, F
Menten, MJ
Fast, MF
Nill, S
Oelfke, U
McDonald, F
Document Type
Journal Article
Date
2017-11-01
Date Accepted
2017-09-09
Abstract
PURPOSE: This study investigates the feasibility and potential benefits of radiotherapy with a 1.5T MR-Linac for locally advanced non-small cell lung cancer (LA NSCLC) patients. MATERIAL AND METHODS: Ten patients with LA NSCLC were retrospectively re-planned six times: three treatment plans were created according to a protocol for conventionally fractionated radiotherapy and three treatment plans following guidelines for isotoxic target dose escalation. In each case, two plans were designed for the MR-Linac, either with standard (∼7mm) or reduced (∼3mm) planning target volume (PTV) margins, while one conventional linac plan was created with standard margins. Treatment plan quality was evaluated using dose-volume metrics or by quantifying dose escalation potential. RESULTS: All generated treatment plans fulfilled their respective planning constraints. For conventionally fractionated treatments, MR-Linac plans with standard margins had slightly increased skin dose when compared to conventional linac plans. Using reduced margins alleviated this issue and decreased exposure of several other organs-at-risk (OAR). Reduced margins also enabled increased isotoxic target dose escalation. CONCLUSION: It is feasible to generate treatment plans for LA NSCLC patients on a 1.5T MR-Linac. Margin reduction, facilitated by an envisioned MRI-guided workflow, enables increased OAR sparing and isotoxic target dose escalation for the respective treatment approaches.
Citation
Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology, 2017, 125 (2), pp. 280 - 285
Source Title
Publisher
ELSEVIER IRELAND LTD
ISSN
0167-8140
eISSN
1879-0887
Collections
Research Team
Radiotherapy Physics Modelling