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Corine Van Es
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P2.01 - Advanced NSCLC (Not CME Accredited Session) (ID 950)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
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P2.01-15 - A Radiologist-Led Training Workshop for MR Based Normal Tissue and Tumour Delineation for Lung Cancer Radiotherapy. (ID 13857)
16:45 - 18:00 | Author(s): Corine Van Es
- Abstract
Background
A potential benefit of MR-image guided radiotherapy (MRIgRT) in lung cancer is the reduction of treatment related uncertainties through improved soft tissue contrast. However, this benefit may be obscured by inter-observer variation in gross tumour volume (GTV) and organ at risk (OAR) contouring. A radiologist led workshop was organised to provide training in such contouring on MR.
a9ded1e5ce5d75814730bb4caaf49419 Method
Planning CT, PET-CT and MRI were acquired in four lung cancer patients. MR sequences included 3D radial gradient echo, T2 DIXON Turbo Spin Echo (TSE), and T2 TSE with and without fat-sat. Data sets were local rigidly registered and imported into the so-called “Big Brother” contouring software.
The radiologist led teaching on OAR and GTV contouring used an MR lung atlas (produced by this group). Seven radiation oncologists contoured the brachial plexus (BP), heart, proximal bronchial tree, oesophagus and GTV. This was followed by a multi-disciplinary group discussion (oncologists, radiologists and physicists) on the contouring challenges and subsequently contours were reviewed and the atlas adjusted.
4c3880bb027f159e801041b1021e88e8 Result
The BP and heart were the most difficult OARs to contour and showed the largest inter-observer variation. Following contour review and discussion between radiologist and oncologists updates to atlas and protocols were made. The GTV was found to be most challenging at the soft tissue interfaces and requires further work (Figure 1).
8eea62084ca7e541d918e823422bd82e Conclusion
This early work demonstrates the need for radiologist-led training in OAR and GTV contouring in lung cancer patients using MR images. This will be especially important for the integration of MR into treatment planning and an MRIgRT adaptive workflow. We have arranged future workshops in order to provide further training and to assess inter-observer variation in OAR and GTV contouring using MR on more cases.
6f8b794f3246b0c1e1780bb4d4d5dc53
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P3.01 - Advanced NSCLC (Not CME Accredited Session) (ID 967)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/26/2018, 12:00 - 13:30, Exhibit Hall
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P3.01-26 - A Framework for Systematic Clinical Evaluation of Technical Innovations in Lung Cancer Patients Treated on the MR-Linac (MRL) (ID 12562)
12:00 - 13:30 | Author(s): Corine Van Es
- Abstract
Background
A recent innovation in radiotherapy is the MRL developed by Elekta and Philips. The MRL combines a 1.5 T MRI with a 7 MV linac. It allows the acquisition of high resolution MR images for on treatment verification, adaption and response monitoring.
a9ded1e5ce5d75814730bb4caaf49419 Method
Seven cancer institutions from Europe and North America, are working within the Elekta MR-Linac Consortium to evaluate the MRL within a framework called ‘R-IDEAL’ (Radiotherapy Idea Development Exploration Assessment Long-term Evaluation) 1.
4c3880bb027f159e801041b1021e88e8 Result
The table below summarizes the ongoing and planned work within the Elekta MR-Linac Consortium.
Progress to date:
8eea62084ca7e541d918e823422bd82e Conclusion
Stage 0: We defined in 80 patients the optimal MRI sequences suitable for GTV and organ at risk (OAR) contouring: T2 Turbo Spin Echo (TSE), T2 TSE with fat sat, T1 radial gradient echo, and DIXON TSE. Two radiology-led workshops were organized and inter-observer agreement was assessed for OARs. These led to a consensus-based OAR atlas. A study is being prepared to compare the image quality of the current standard CBCT and MR images at baseline and mid-treatment for treatment verification and set-up correction.
Stage 1: we will investigate the clinical feasibility of the MRL for standard of care radiotherapy and the scope for adaptive radiotherapy (margin reductions) and detecting changes in oxygenation during treatment on the MRL in patients with locally advanced (LA) NSCLC .
Stage 2a/b : Based on the results from stage 1 we will design a study aiming to reduce margins around the tumour and dose escalate in patients with LA NSCLC.
The aim of this programme of work is to generate robust evidence to support the introduction of the MRL and to improve outcomes of patients with LA NSCLC.
6f8b794f3246b0c1e1780bb4d4d5dc53
