MRI-Guided Online Adaptive Stereotactic Body Radiation Therapy of Liver and Pancreas Tumors on an MR-Linac System

Cancers - Tập 14 Số 3 - Trang 716
T. Stanescu1,2,3, Andrea Shessel3, Cathy Carpino-Rocca3, Edward Taylor2,3, Oleksii Semeniuk3, Winnie Li3, Aisling Barry2,3, Jelena Lukovic2,3, Laura A. Dawson2,3, Ali Hosni2,3
1Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON M5S 3G8, Canada
2Department of Radiation Oncology, University of Toronto, Toronto, ON, M5T 1P5, Canada
3Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2M9, Canada

Tóm tắt

Purpose: To describe a comprehensive workflow for MRI-guided online adaptive stereotactic body radiation therapy (SBRT) specific to upper gastrointestinal cancer patients with abdominal compression on a 1.5T MR-Linac system. Additionally, we discuss the workflow’s clinical feasibility and early experience in the case of 16 liver and pancreas patients. Methods: Eleven patients with liver cancer and five patients with pancreas cancer were treated with online adaptive MRI-guidance under abdominal compression. Two liver patients received single-fraction treatments; the remainder plus all pancreas cancer patients received five fractions. A total of 65 treatment sessions were investigated to provide analytics relevant to the online adaptive processes. The quantification of target and organ motion as well as definition and validation of internal target volume (ITV) margins were performed via multi-contrast imaging provided by three different 2D cine sequences. The plan generation was driven by full re-optimization strategies and using T2-weighted 3D image series acquired by means of a respiratory-triggered exhale phase or a time-averaged imaging protocol. As a pre-requisite for the clinical development of the procedure, the image quality was thoroughly investigated via phantom measurements and numerical simulations specific to upper abdominal sites. The delivery of the online adaptive treatments was facilitated by real-time monitoring with 2D cine imaging. Results: Liver 1-fraction and 5-fraction online adaptive session time were on average 80 and 67.5 min, respectively. The total session length varied between 70–90 min for a single fraction and 55–90 min for five fractions. The pancreas sessions were 54–85 min long with an average session time of 68.2 min. Target visualization on the 2D cine image data varied per patient, with at least one of the 2D cine sequences providing sufficient contrast to confidently identify its location and confirm reproducibility of ITV margins. The mean/range of absolute and relative dose values for all treatment sessions evaluated with ArcCheck were 90.6/80.9–96.1% and 99/95.4–100%, respectively. Conclusion: MR-guidance is feasible for liver and pancreas tumors when abdominal compression is used to reduce organ motion, improve imaging quality, and achieve a robust intra- and inter-fraction patient setup. However, the treatment length is significantly longer than for the conventional linac, and patient compliance is paramount for the successful completion of the treatment. Opportunities for reducing the online adaptive session time should be explored. As the next steps, dose-of-the-day and dose accumulation analysis and tools are needed to enhance the workflow and to help further refine the online re-planning processes.

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Tài liệu tham khảo

Mutic, 2014, The ViewRay system: Magnetic resonance-guided and controlled radiotherapy, Semin. Radiat. Oncol., 24, 196, 10.1016/j.semradonc.2014.02.008

Raaymakers, 2011, Integrated megavoltage portal imaging with a 1.5 T MRI linac, Phys. Med. Biol., 56, N207, 10.1088/0031-9155/56/19/N01

Fallone, 2009, First MR images obtained during megavoltage photon irradiation from a prototype integrated linac-MR system, Med. Phys., 36, 2084, 10.1118/1.3125662

Keall, 2014, Australian Mri-Linac Program icfIIICCCLHSUUoNQSWS, Wollongong. The Australian magnetic resonance imaging-linac program, Semin. Radiat. Oncol., 24, 203, 10.1016/j.semradonc.2014.02.015

Witt, 2020, MRI-guided adaptive radiotherapy for liver tumours: Visualising the future, Lancet Oncol., 21, e74, 10.1016/S1470-2045(20)30034-6

Reyngold, 2019, Ablative radiation therapy for locally advanced pancreatic cancer: Techniques and results, Radiat. Oncol., 14, 95, 10.1186/s13014-019-1309-x

Paulson, 2020, 4D-MRI driven MR-guided online adaptive radiotherapy for abdominal stereotactic body radiation therapy on a high field MR-Linac: Implementation and initial clinical experience, Clin. Transl. Radiat. Oncol., 23, 72

Tyagi, 2021, Feasibility of ablative stereotactic body radiation therapy of pancreas cancer patients on a 1.5 Tesla magnetic resonance-linac system using abdominal compression, Phys. Imaging Radiat. Oncol., 19, 53, 10.1016/j.phro.2021.07.006

Stanescu, 2018, Technical Note: Harmonic analysis applied to MR image distortion fields specific to arbitrarily shaped volumes, Med. Phys., 45, 3705, 10.1002/mp.13000

Stanescu, 2021, Quantification of magnetic susceptibility fingerprint of a 3D linearity medical device, Phys. Med., 87, 39, 10.1016/j.ejmp.2021.05.023

Stanescu, 2012, Characterization of tissue magnetic susceptibility-induced distortions for MRIgRT, Med. Phys., 39, 7185, 10.1118/1.4764481

Stanescu, 2016, Investigation of the 4D composite MR image distortion field associated with tumor motion for MR-guided radiotherapy, Med. Phys., 43, 1550, 10.1118/1.4941958

Elamir, 2021, Simulated dose painting of hypoxic sub-volumes in pancreatic cancer stereotactic body radiotherapy, Phys. Med. Biol., 66, 185008, 10.1088/1361-6560/ac215c

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Cancers

Tập 14 Số 3

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