Purpose: A 1.5 T MR Linac (MRL) has recently become available. MRL treatment workflows (WF) include online plan adaptation based on daily MR images (MRI). This study reports initial clinical experiences after five months of use in terms of patient compliance, cases, WF timings, and dosimetric accuracy. Method and materials: Two different WF were used dependent on the clinical situation of the day; Adapt To Position WF (ATP) where the reference plan position is adjusted rigidly to match the position of the targets and the OARs, and Adapt To Shape WF (ATS), where a new plan is created to match the anatomy of the day, using deformable image registration. Both WFs included three 3D MRI scans for plan adaptation, verification before beam on, and validation during IMRT delivery. Patient compliance and WF timings were recorded. Accuracy in dose delivery was assessed using a cylindrical diode phantom. Results: Nineteen patients have completed their treatment receiving a total of 176 fractions. Cases vary from prostate treatments (60Gy/20F) to SBRT treatments of lymph nodes (45 Gy/3F) and castration by ovarian irradiation (15 Gy/3F). The median session time (patient in to patient out) for 127 ATPs was 26 (21-78) min, four fractions lasted more than 45 min due to additional plan adaptation. For the 49 ATSs a median time of 12 (1-24) min was used for contouring resulting in a total median session time of 42 (29-91) min. Three SBRT fractions lasted more than an hour. The time on the MRL couch was well tolerated by the patients. The median gamma pass rate (2 mm,2% global max) for the adapted plans was 99.2 (93.4-100)%, showing good agreement between planned and delivered dose. Conclusion: MRL treatments, including daily MRIs, plan adaptation, and accurate dose delivery, are possible within a clinically acceptable timeframe and well tolerated by the patients.
Purpose: A 1.5 T MR Linac (MRL) has recently become available. MRL treatment workflows (WF) include online plan adaptation based on daily MR images (MRI). This study reports initial clinical experiences after five months of use in terms of patient compliance, cases, WF timings, and dosimetric accuracy. Method and materials: Two different WF were used dependent on the clinical situation of the day; Adapt To Position WF (ATP) where the reference plan position is adjusted rigidly to match the position of the targets and the OARs, and Adapt To Shape WF (ATS), where a new plan is created to match the anatomy of the day, using deformable image registration. Both WFs included three 3D MRI scans for plan adaptation, verification before beam on, and validation during IMRT delivery. Patient compliance and WF timings were recorded. Accuracy in dose delivery was assessed using a cylindrical diode phantom. Results: Nineteen patients have completed their treatment receiving a total of 176 fractions. Cases vary from prostate treatments (60Gy/20F) to SBRT treatments of lymph nodes (45 Gy/3F) and castration by ovarian irradiation (15 Gy/3F). The median session time (patient in to patient out) for 127 ATPs was 26 (21-78) min, four fractions lasted more than 45 min due to additional plan adaptation. For the 49 ATSs a median time of 12 (1-24) min was used for contouring resulting in a total median session time of 42 (29-91) min. Three SBRT fractions lasted more than an hour. The time on the MRL couch was well tolerated by the patients. The median gamma pass rate (2 mm,2% global max) for the adapted plans was 99.2 (93.4-100)%, showing good agreement between planned and delivered dose. Conclusion: MRL treatments, including daily MRIs, plan adaptation, and accurate dose delivery, are possible within a clinically acceptable timeframe and well tolerated by the patients.
Authors: Brigid A McDonald; Sastry Vedam; Jinzhong Yang; Jihong Wang; Pamela Castillo; Belinda Lee; Angela Sobremonte; Sara Ahmed; Yao Ding; Abdallah S R Mohamed; Peter Balter; Neil Hughes; Daniela Thorwarth; Marcel Nachbar; Marielle E P Philippens; Chris H J Terhaard; Daniel Zips; Simon Böke; Musaddiq J Awan; John Christodouleas; Clifton D Fuller Journal: Int J Radiat Oncol Biol Phys Date: 2020-12-16 Impact factor: 7.038
Authors: John Rodgers; Rosie Hales; Lee Whiteside; Jacqui Parker; Louise McHugh; Anthea Cree; Marcel van Herk; Ananya Choudhury; Peter Hoskin; Alan McWilliam; Cynthia L Eccles Journal: Br J Radiol Date: 2020-06-16 Impact factor: 3.039
Authors: David S Lakomy; Jinzhong Yang; Sastry Vedam; Jihong Wang; Belinda Lee; Angela Sobremonte; Pamela Castillo; Neil Hughes; Mustefa Mohammedsaid; Anuja Jhingran; Ann H Klopp; Seungtaek Choi; C David Fuller; Lilie L Lin Journal: Pract Radiat Oncol Date: 2022-03-09
Authors: Thomas Willigenburg; Daan M de Muinck Keizer; Max Peters; An Claes; Jan J W Lagendijk; Hans C J de Boer; Jochem R N van der Voort van Zyp Journal: Clin Transl Radiat Oncol Date: 2021-01-14
Authors: Christopher Kurz; Giulia Buizza; Guillaume Landry; Florian Kamp; Moritz Rabe; Chiara Paganelli; Guido Baroni; Michael Reiner; Paul J Keall; Cornelis A T van den Berg; Marco Riboldi Journal: Radiat Oncol Date: 2020-05-05 Impact factor: 3.481
Authors: A Hunt; I Hanson; A Dunlop; H Barnes; L Bower; J Chick; C Cruickshank; E Hall; T Herbert; R Lawes; D McQuaid; H McNair; A Mitchell; J Mohajer; T Morgan; U Oelfke; G Smith; S Nill; R Huddart; S Hafeez Journal: Clin Transl Radiat Oncol Date: 2020-09-11