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Yan L, Xu Y, Dai J. Impact of 1.5 T Magnetic Field on Treatment Plan Quality in MR-Guided Radiotherapy: Typical Phantom Test Cases. Technol Cancer Res Treat 2024; 23:15330338241272038. [PMID: 39106410 PMCID: PMC11307342 DOI: 10.1177/15330338241272038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/31/2024] [Accepted: 07/01/2024] [Indexed: 08/09/2024] Open
Abstract
PURPOSE This study aims to investigate the influence of the magnetic field on treatment plan quality using typical phantom test cases, which encompass a circle target test case, AAPM TG119 test cases (prostate, head-and-neck, C-shape, multi-target test cases), and a lung test case. MATERIALS AND METHODS For the typical phantom test cases, two plans were formulated. The first plan underwent optimization in the presence of a 1.5 Tesla magnetic field (1.5 T plan). The second plan was re-optimized without a magnetic field (0 T plan), utilizing the same optimization conditions as the first plan. The two plans were compared based on various parameters, including con-formity index (CI), homogeneity index (HI), fit index (FI) and dose coverage of the planning target volume (PTV), dose delivered to organs at risk (OARs) and normal tissue (NT), monitor unit (MU). A plan-quality metric (PQM) scoring procedure was employed. For the 1.5 T plans, dose verifications were performed using an MR-compatible ArcCHECK phantom. RESULTS A smaller dose influence of the magnetic field was found for the circle target, prostate, head-and-neck, and C-shape test cases, compared with the multi-target and lung test cases. In the multi-target test case, the significant dose influence was on the inferior PTV, followed by the superior PTV. There was a relatively large dose influence on the PTV and OARs for lung test case. No statistically significant differences in PQM and MUs were observed. For the 1.5 T plans, gamma passing rates were all higher than 95% with criteria of 2 mm/3% and 2 mm/2%. CONCLUSION The presence of a 1.5 T magnetic field had a relatively large impact on dose parameters in the multi-target and lung test cases compared with other test cases. However, there were no significant influences on the plan-quality metric, MU and dose accuracy for all test cases.
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Affiliation(s)
- Lingling Yan
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yingjie Xu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Onal C, Efe E, Bozca R, Yavas C, Yavas G, Arslan G. The impact of margin reduction on radiation dose distribution of ultra-hypofractionated prostate radiotherapy utilizing a 1.5-T MR-Linac. J Appl Clin Med Phys 2024; 25:e14179. [PMID: 38013636 PMCID: PMC10795449 DOI: 10.1002/acm2.14179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/21/2023] [Accepted: 09/28/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND We examined the effects of reducing the planning target volume (PTV) margin in MR-guided radiotherapy (MRgRT) on the distribution of radiation dose to target volumes and organs-at-risk (OARs). Thus, we compared MR-Linac (MRL) plans with and without reduced margin and intensity-modulated radiotherapy (IMRT) plan with conventional linac for low-risk prostate cancer patients receiving 36.25 Gy in five fractions of ultra-hypofractionated radiation therapy. MATERIALS AND METHODS Twenty low-risk prostate cancer patients treated with 1.5 T MR-Linac were evaluated. The same planning CT images were used for four plans: the MRL-R plan with reduced margin planning target volume (PTV-R) and the MRL-N plan with normal margin PTV (PTV-N), which is also used for IMRT plan. In four plans, PTV doses, organs-at-risk (OARs) doses, the homogeneity index (HI), and monitor units were compared. RESULTS All plans met the criteria for PTV coverage and OARs dose constraints. The maximum and mean PTV doses were significantly higher in the MRL-R and MRL-N plans compared to the IMRT plan. The HI was lowest in the IMRT plan (0.040 ± 0.013) and highest in the MRL-N plan (0.055 ± 0.012; p < 0.001). There was no significant difference in the PTV dosimetric parameters between the MRL-R and the MRL-N plans. The high doses in the rectum was significantly lower in the MRL-R compared to other plans. The bladder V36.25 Gy was significantly lower in the MRL-R plan (2.43 ± 1.87 Gy) compared to MRL-N (4.50 ± 2.42 Gy; p < 0.001), and IMRT plans (4.76 ± 2.77 Gy; p < 0.001). There was no significant difference in the low-dose volumes of the body, maximum femur doses, or monitor units across each plan. CONCLUSIONS Ultra-hypofractionated MR-guided RT with 1.5 T MRL is dosimetrically feasible for patients with prostate cancer. The improved soft tissue contrast and the online adaptive plan for 1.5 T MR-Linac allows for PTV margin reduction resulted in a significant dose reduction in OARs.
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Affiliation(s)
- Cem Onal
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
- Adana Dr. Turgut Noyan Research and Treatment CenterDepartment of Radiation OncologyBaskent University Faculty of MedicineAdanaTurkey
| | - Esma Efe
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
| | - Recep Bozca
- Adana Dr. Turgut Noyan Research and Treatment CenterDepartment of Radiation OncologyBaskent University Faculty of MedicineAdanaTurkey
| | - Cagdas Yavas
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
| | - Guler Yavas
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
| | - Gungor Arslan
- Faculty of MedicineDepartment of Radiation OncologyBaskent UniversityAnkaraTurkey
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Han EY, Yeboa DN, Briere TM, Yang J, Wang H. Dosimetric analysis of MR-LINAC treatment plans for salvage spine SBRT re-irradiation. J Appl Clin Med Phys 2022; 23:e13752. [PMID: 36004700 DOI: 10.1002/acm2.13752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 05/16/2022] [Accepted: 07/25/2022] [Indexed: 11/09/2022] Open
Abstract
PURPOSE We investigated the feasibility of thoracic spine stereotactic body radiotherapy (SBRT) using the Elekta Unity magnetic resonance-guided linear accelerator (MRL) in patients who received prior radiotherapy. We hypothesized that Monaco treatment plans can improve the gross tumor volume minimum dose (GTVmin) with spinal cord preservation and maintain consistent plan quality during daily adaptation. METHODS Pinnacle clinical plans for 10 patients who underwent thoracic spine SBRT (after prior radiotherapy) were regenerated in the Monaco treatment planning system for the Elekta Unity MRL using 9 and 13 intensity-modulated radiotherapy (IMRT) beams. Monaco adapt-to-position (ATP) and adapt-to-shape (ATS) workflow plans were generated using magnetic resonance imaging with a simulated daily positional setup deviation, and these adaptive plans were compared with Monaco reference plans. Plan quality measures included target coverage, Paddick conformity index, gradient index, homogeneity index, spinal cord D0.01cc , esophagus D0.01cc , lung V10, and skin D0.01cc . RESULTS GTVmin values from the Monaco 9-beam and 13-beam plans were significantly higher than those from Pinnacle plans (p < 0.01) with similar spinal cord dose. Spinal cord D0.01cc , esophagus D0.01cc , and lung V10 did not statistically differ among the three plans. The electron-return effect did not induce remarkable dose effects around the lungs or skin. While in the ATP workflow, a large increase in GTVmin was observed at the cost of a 10%-50% increase in spinal cord D0.01cc , in the ATS workflow, the spinal cord dose increase was maintained within 3% of the reference plan. CONCLUSION These findings show that MRL plans for thoracic spine SBRT are safe and feasible, allowing tumor dose escalation with spinal cord preservation and consistent daily plan adaptation using the ATS workflow. Careful plan review of hot spots and lung dose is necessary for safe MRL-based treatment.
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Affiliation(s)
- Eun Young Han
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Debra N Yeboa
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tina M Briere
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jinzhong Yang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - He Wang
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
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Kong VC, Dang J, Li W, Navarro I, Padayachee J, Malkov V, Winter J, Raman S, Berlin A, Catton C, Warde P, Chung P. Dosimetric comparison of MR-guided adaptive IMRT versus 3DOF-VMAT for prostate stereotactic radiotherapy. Tech Innov Patient Support Radiat Oncol 2022; 21:64-70. [PMID: 35252598 PMCID: PMC8892164 DOI: 10.1016/j.tipsro.2022.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/13/2022] [Accepted: 02/09/2022] [Indexed: 11/15/2022] Open
Abstract
Prostate SBRT are treated using MR-guided adaptive IMRT (A-IMRT) and VMAT based on translation correction (3DOF-VMAT) at our institution. Comparison of reference and delivered dose between adaptive-IMRT and 3DOF-VMAT to assess the effect of interfractional motion. Despite large interfractional changes, prostate received clinically acceptable dose with a margin of 5 mm through either A-IMRT or 3DOF-VMAT. A-IMRT was more superior than 3DOF-VMAT in sparing the rectum in the high dose region; no difference between the two systems was observed for bladder.
Introduction Methods & Materials Results Conclusions
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Affiliation(s)
- Vickie C. Kong
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
- Corresponding author at: Princess Margaret Cancer Centre, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
| | - Jennifer Dang
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
| | - Winnie Li
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Inmaculada Navarro
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Jerusha Padayachee
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Victor Malkov
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Jeff Winter
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Srinivas Raman
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Alejandro Berlin
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Charles Catton
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Padraig Warde
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
| | - Peter Chung
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, Canada
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Lübeck Christiansen R, Dysager L, Rønn Hansen C, Robenhagen Jensen H, Schytte T, Junker Nyborg C, Smedegaard Bertelsen A, Nielsen Agergaard S, Mahmood F, Hansen S, Hansen O, Brink C, Bernchou U. Online adaptive radiotherapy potentially reduces toxicity for high-risk prostate cancer treatment. Radiother Oncol 2021; 167:165-171. [PMID: 34923034 DOI: 10.1016/j.radonc.2021.12.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/22/2021] [Accepted: 12/10/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND PURPOSE With daily, MR-guided online adapted radiotherapy (MRgART) it may be possible to reduce the PTV in pelvic RT. This study investigated the potential reduction in normal tissue complication probability (NTCP) of MRgART compared to standard radiotherapy for high-risk prostate cancer. MATERIALS AND METHODS Twenty patients treated with 78 Gy to the prostate and 56 Gy to elective pelvic lymph nodes were included. VMAT plans were generated with standard clinical PTV margins. Additionally to the planning MR, patients had three MRI scans during treatment to simulate an MRgART. A reference plan with PTV margins determined for MRgART was created per patient and adapted to each of the following MRs. Adapted plans were warped to the planning MR for dose accumulation. The standard plan was rigidly registered to each adaptation MR before it was warped to the planning MR for dose accumulation. Dosimetric impact was compared by DVH analysis and potential clinical effects were assessed by NTCP modeling. RESULTS MRgART yielded statistically significant lower doses for the bladder wall, rectum and peritoneal cavity, compared to the standard RT, which translated into reduced median risks of urine incontinence (ΔNTCP 2.8%), urine voiding pain (ΔNTCP 2.8%) and acute gastrointestinal toxicity (ΔNTCP 17.4%). Mean population accumulated doses were as good or better for all investigated OAR when planned for MRgART as standard RT. CONCLUSION Online adapted radiotherapy may reduce the dose to organs at risk in high-risk prostate cancer patients, due to reduced PTV margins. This potentially translates to significant reductions in the risks of acute and late adverse effects.
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Affiliation(s)
- Rasmus Lübeck Christiansen
- Department of Clinical Research, University of Southern Denmark; Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital.
| | - Lars Dysager
- Department of Oncology, Odense University Hospital
| | - Christian Rønn Hansen
- Department of Clinical Research, University of Southern Denmark; Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital
| | | | - Tine Schytte
- Department of Clinical Research, University of Southern Denmark; Department of Oncology, Odense University Hospital
| | | | | | | | - Faisal Mahmood
- Department of Clinical Research, University of Southern Denmark; Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital
| | | | - Olfred Hansen
- Department of Clinical Research, University of Southern Denmark; Department of Oncology, Odense University Hospital
| | - Carsten Brink
- Department of Clinical Research, University of Southern Denmark; Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital
| | - Uffe Bernchou
- Department of Clinical Research, University of Southern Denmark; Laboratory of Radiation Physics, Department of Oncology, Odense University Hospital
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Bijman R, Rossi L, Janssen T, de Ruiter P, van Triest B, Breedveld S, Sonke JJ, Heijmen B. MR-Linac Radiotherapy - The Beam Angle Selection Problem. Front Oncol 2021; 11:717681. [PMID: 34660281 PMCID: PMC8518312 DOI: 10.3389/fonc.2021.717681] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 09/09/2021] [Indexed: 11/13/2022] Open
Abstract
Background With the large-scale introduction of volumetric modulated arc therapy (VMAT), selection of optimal beam angles for coplanar static-beam IMRT has increasingly become obsolete. Due to unavailability of VMAT in current MR-linacs, the problem has re-gained importance. An application for automated IMRT treatment planning with integrated, patient-specific computer-optimization of beam angles (BAO) was used to systematically investigate computer-aided generation of beam angle class solutions (CS) for replacement of computationally expensive patient-specific BAO. Rectal cancer was used as a model case. Materials and Methods 23 patients treated at a Unity MR-linac were included. BAOx plans (x=7-12 beams) were generated for all patients. Analyses of BAO12 plans resulted in CSx class solutions. BAOx plans, CSx plans, and plans with equi-angular setups (EQUIx, x=9-56) were mutually compared. Results For x>7, plan quality for CSx and BAOx was highly similar, while both were superior to EQUIx. E.g. with CS9, bowel/bladder Dmean reduced by 22% [11%, 38%] compared to EQUI9 (p<0.001). For equal plan quality, the number of EQUI beams had to be doubled compared to BAO and CS. Conclusions Computer-generated beam angle CS could replace individualized BAO without loss in plan quality, while reducing planning complexity and calculation times, and resulting in a simpler clinical workflow. CS and BAO largely outperformed equi-angular treatment. With the developed CS, time consuming beam angle re-optimization in daily adaptive MR-linac treatment could be avoided. Further systematic research on computerized development of beam angle class solutions for MR-linac treatment planning is warranted.
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Affiliation(s)
- Rik Bijman
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands
| | - Linda Rossi
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands
| | - Tomas Janssen
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Peter de Ruiter
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Baukelien van Triest
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, Netherlands
| | | | - Jan-Jakob Sonke
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands
| | - Ben Heijmen
- Department of Radiotherapy, Erasmus MC Cancer Institute, Rotterdam, Netherlands
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Da Silva Mendes V, Nierer L, Li M, Corradini S, Reiner M, Kamp F, Niyazi M, Kurz C, Landry G, Belka C. Dosimetric comparison of MR-linac-based IMRT and conventional VMAT treatment plans for prostate cancer. Radiat Oncol 2021; 16:133. [PMID: 34289868 PMCID: PMC8296626 DOI: 10.1186/s13014-021-01858-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/12/2021] [Indexed: 02/07/2023] Open
Abstract
Background The aim of this study was to evaluate and compare the performance of intensity modulated radiation therapy (IMRT) plans, planned for low-field strength magnetic resonance (MR) guided linear accelerator (linac) delivery (labelled IMRT MRL plans), and clinical conventional volumetric modulated arc therapy (VMAT) plans, for the treatment of prostate cancer (PCa). Both plans used the original planning target volume (PTV) margins. Additionally, the potential dosimetric benefits of MR-guidance were estimated, by creating IMRT MRL plans using smaller PTV margins. Materials and methods 20 PCa patients previously treated with conventional VMAT were considered. For each patient, two different IMRT MRL plans using the low-field MR-linac treatment planning system were created: one with original (orig.) PTV margins and the other with reduced (red.) PTV margins. Dose indices related to target coverage, as well as dose-volume histogram (DVH) parameters for the target and organs at risk (OAR) were compared. Additionally, the estimated treatment delivery times and the number of monitor units (MU) of each plan were evaluated. Results The dose distribution in the high dose region and the target volume DVH parameters (D98%, D50%, D2% and V95%) were similar for all three types of treatment plans, with deviations below 1% in most cases. Both IMRT MRL plans (orig. and red. PTV margins) showed similar homogeneity indices (HI), however worse values for the conformity index (CI) were also found when compared to VMAT. The IMRT MRL plans showed similar OAR sparing when the orig. PTV margins were used but a significantly better sparing was feasible when red. PTV margins were applied. Higher number of MU and longer predicted treatment delivery times were seen for both IMRT MRL plans. Conclusions A comparable plan quality between VMAT and IMRT MRL plans was achieved, when applying the same PTV margin. However, online MR-guided adaptive radiotherapy allows for a reduction of PTV margins. With a red. PTV margin, better sparing of the surrounding tissues can be achieved, while maintaining adequate target coverage. Nonetheless, longer treatment delivery times, characteristic for the IMRT technique, have to be expected.
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Affiliation(s)
- Vanessa Da Silva Mendes
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.
| | - Lukas Nierer
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Minglun Li
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Stefanie Corradini
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Michael Reiner
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Florian Kamp
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.,Department of Radiation Oncology, Cologne University Hospital, Cologne, Germany
| | - Maximilian Niyazi
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Christopher Kurz
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Guillaume Landry
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany
| | - Claus Belka
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, 81377, Munich, Germany.,German Cancer Consortium (DKTK), Partner Site Munich, Munich, Germany
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Fuchs H, Padilla‐Cabal F, Zimmermann L, Palmans H, Georg D. MR-guided proton therapy: Impact of magnetic fields on the detector response. Med Phys 2021; 48:2572-2579. [PMID: 33326614 PMCID: PMC8251909 DOI: 10.1002/mp.14660] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/03/2020] [Accepted: 12/03/2020] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the response of detectors for proton dosimetry in the presence of magnetic fields. MATERIAL AND METHODS Four ionization chambers (ICs), two thimble-type and two plane-parallel-type, and a diamond detector were investigated. All detectors were irradiated with homogeneous single-energy-layer fields, using 252.7 MeV proton beams. A Farmer IC was additionally irradiated in the same geometrical configuration, but with a lower nominal energy of 97.4 MeV. The beams were subjected to magnetic field strengths of 0, 0.25, 0.5, 0.75, and 1 T produced by a research dipole magnet placed at the room's isocenter. Detectors were positioned at 2 cm water equivalent depth, with their stem perpendicular to both the magnetic field lines and the proton beam's central axis, in the direction of the Lorentz force. Normality and two sample statistical Student's t tests were performed to assess the influence of the magnetic field on the detectors' responses. RESULTS For all detectors, a small but significant magnetic field-dependent change of their response was found. Observed differences compared to the no magnetic field case ranged from +0.5% to -0.7%. The magnetic field dependence was found to be nonlinear and highest between 0.25 and 0.5 T for 252.7 MeV proton beams. A different variation of the Farmer chamber response with magnetic field strength was observed for irradiations using lower energy (97.4 MeV) protons. The largest magnetic field effects were observed for plane-parallel ionization chambers. CONCLUSION Small magnetic field-dependent changes in the detector response were identified, which should be corrected for dosimetric applications.
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Affiliation(s)
- Hermann Fuchs
- Division of Medical PhysicsDepartment of Radiation OncologyMedical University of Vienna1090ViennaAustria
- Division of Medical PhysicsMedAustron Ion Therapy Center2700Wiener NeustadtAustria
| | - Fatima Padilla‐Cabal
- Division of Medical PhysicsDepartment of Radiation OncologyMedical University of Vienna1090ViennaAustria
| | - Lukas Zimmermann
- Division of Medical PhysicsDepartment of Radiation OncologyMedical University of Vienna1090ViennaAustria
| | - Hugo Palmans
- Division of Medical PhysicsMedAustron Ion Therapy Center2700Wiener NeustadtAustria
- National Physical LaboratoryTW11 0LWTeddingtonUnited Kingdom
| | - Dietmar Georg
- Division of Medical PhysicsDepartment of Radiation OncologyMedical University of Vienna1090ViennaAustria
- Division of Medical PhysicsMedAustron Ion Therapy Center2700Wiener NeustadtAustria
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Chin S, Eccles CL, McWilliam A, Chuter R, Walker E, Whitehurst P, Berresford J, Van Herk M, Hoskin PJ, Choudhury A. Magnetic resonance-guided radiation therapy: A review. J Med Imaging Radiat Oncol 2020; 64:163-177. [PMID: 31646742 DOI: 10.1111/1754-9485.12968] [Citation(s) in RCA: 89] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 09/24/2019] [Indexed: 12/11/2022]
Abstract
Magnetic resonance-guided radiation therapy (MRgRT) is a promising approach to improving clinical outcomes for patients treated with radiation therapy. The roles of image guidance, adaptive planning and magnetic resonance imaging in radiation therapy have been increasing over the last two decades. Technical advances have led to the feasible combination of magnetic resonance imaging and radiation therapy technologies, leading to improved soft-tissue visualisation, assessment of inter- and intrafraction motion, motion management, online adaptive radiation therapy and the incorporation of functional information into treatment. MRgRT can potentially transform radiation oncology by improving tumour control and quality of life after radiation therapy and increasing convenience of treatment by shortening treatment courses for patients. Multiple groups have developed clinical implementations of MRgRT predominantly in the abdomen and pelvis, with patients having been treated since 2014. While studies of MRgRT have primarily been dosimetric so far, an increasing number of trials are underway examining the potential clinical benefits of MRgRT, with coordinated efforts to rigorously evaluate the benefits of the promising technology. This review discusses the current implementations, studies, potential benefits and challenges of MRgRT.
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Affiliation(s)
- Stephen Chin
- Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
- Westmead Clinical School, University of Sydney, Sydney, New South Wales, Australia
| | - Cynthia L Eccles
- Department of Radiotherapy, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
| | - Alan McWilliam
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Robert Chuter
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Emma Walker
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Philip Whitehurst
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Joseph Berresford
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Marcel Van Herk
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK
| | - Peter J Hoskin
- Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
| | - Ananya Choudhury
- Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, UK
- Division of Cancer Sciences, The University of Manchester, Manchester, UK
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10
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van den Wollenberg W, de Ruiter P, Nowee ME, Jansen EPM, Sonke J, Fast MF. Investigating the impact of patient arm position in an MR‐linac on liver SBRT treatment plans. Med Phys 2019; 46:5144-5151. [DOI: 10.1002/mp.13826] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/22/2019] [Accepted: 09/10/2019] [Indexed: 12/22/2022] Open
Affiliation(s)
- Wouter van den Wollenberg
- Department of Radiation Oncology The Netherlands Cancer Institute Plesmanlaan 121 1066 CX Amsterdam The Netherlands
| | - Peter de Ruiter
- Department of Radiation Oncology The Netherlands Cancer Institute Plesmanlaan 121 1066 CX Amsterdam The Netherlands
| | - Marlies E. Nowee
- Department of Radiation Oncology The Netherlands Cancer Institute Plesmanlaan 121 1066 CX Amsterdam The Netherlands
| | - Edwin P. M. Jansen
- Department of Radiation Oncology The Netherlands Cancer Institute Plesmanlaan 121 1066 CX Amsterdam The Netherlands
| | - Jan‐Jakob Sonke
- Department of Radiation Oncology The Netherlands Cancer Institute Plesmanlaan 121 1066 CX Amsterdam The Netherlands
| | - Martin F. Fast
- Department of Radiation Oncology The Netherlands Cancer Institute Plesmanlaan 121 1066 CX Amsterdam The Netherlands
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11
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Cusumano D, Boldrini L, Menna S, Teodoli S, Placidi E, Chiloiro G, Placidi L, Greco F, Stimato G, Cellini F, Valentini V, Azario L, De Spirito M. Evaluation of a simplified optimizer for MR-guided adaptive RT in case of pancreatic cancer. J Appl Clin Med Phys 2019; 20:20-30. [PMID: 31444952 PMCID: PMC6753732 DOI: 10.1002/acm2.12697] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Magnetic resonance-guided adaptive radiotherapy (MRgART) is considered a promising resource for pancreatic cancer, as it allows to online modify the dose distribution according to daily anatomy. This study aims to compare the dosimetric performance of a simplified optimizer implemented on a MR-Linac treatment planning system (TPS) with those obtained using an advanced optimizer implemented on a conventional Linac. METHODS Twenty patients affected by locally advanced pancreatic cancer (LAPC) were considered. Gross tumor volume (GTV) and surrounding organ at risks (OARs) were contoured on the average 4DCT scan. Planning target volume was generated from GTV by adding an isotropic 3 mm margin and excluding overlap areas with OARs. Treatment plans were generated by using the simple optimizer for the MR-Linac in intensity-modulated radiation therapy (IMRT) and the advanced optimizer for conventional Linac in IMRT and volumetric modulated arc therapy (VMAT) technique. Prescription dose was 40 Gy in five fractions. The dosimetric comparison was performed on target coverage, dosimetric indicators, and low dose diffusion. RESULTS The simplified optimizer of MR-Linac generated clinically acceptable plans in 80% and optimal plans in 55% of cases. The number of clinically acceptable plans obtained using the advanced optimizer of the conventional Linac with IMRT was the same of MR-Linac, but the percentage of optimal plans was higher (65%). Using the VMAT technique, it is possible to obtain clinically acceptable plan in 95% and optimal plans in 90% of cases. The advanced optimizer combined with VMAT technique ensures higher target dose homogeneity and minor diffusion of low doses, but its actual optimization time is not suitable for MRgART. CONCLUSION Simplified optimization solutions implemented in the MR-Linac TPS allows to elaborate in most of cases treatment plans dosimetrically comparable with those obtained by using an advanced optimizer. A superior treatment plan quality is possible using the VMAT technique that could represent a breakthrough for the MRgART if the modern advancements will lead to shorter optimization times.
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Affiliation(s)
- Davide Cusumano
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Luca Boldrini
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Sebastiano Menna
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Stefania Teodoli
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Elisa Placidi
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Giuditta Chiloiro
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Lorenzo Placidi
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Francesca Greco
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Gerardina Stimato
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Francesco Cellini
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
| | - Vincenzo Valentini
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
- Istituto di RadiologiaUniversità Cattolica del Sacro CuoreRomaItaly
| | - Luigi Azario
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
- Istituto di FisicaUniversità Cattolica del Sacro CuoreRomaItaly
| | - Marco De Spirito
- Dipartimento di diagnostica per immagini, radioterapia oncologica ed ematologiaFondazione Policlinico Universitario “A. Gemelli” IRCCSRomaItaly
- Istituto di FisicaUniversità Cattolica del Sacro CuoreRomaItaly
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den Hartogh MD, de Boer HC, de Groot-van Breugel EN, van der Voort van Zyp JR, Hes J, van der Heide UA, Pos F, Haustermans K, Depuydt T, Jan Smeenk R, Kunze-Busch M, Raaymakers BW, Kerkmeijer LG. Planning feasibility of extremely hypofractionated prostate radiotherapy on a 1.5 T magnetic resonance imaging guided linear accelerator. Phys Imaging Radiat Oncol 2019; 11:16-20. [PMID: 33458271 PMCID: PMC7807729 DOI: 10.1016/j.phro.2019.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/03/2019] [Accepted: 07/03/2019] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND AND PURPOSE Recently, intermediate and high-risk prostate cancer patients have been treated in a multicenter phase II trial with extremely hypofractionated prostate radiotherapy (hypo-FLAME trial). The purpose of the current study was to investigate whether a 1.5 T magnetic resonance imaging guided linear accelerator (MRI-linac) could achieve complex dose distributions of a quality similar to conventional linac state-of-the-art prostate treatments. MATERIALS AND METHODS The clinically delivered treatment plans of 20 hypo-FLAME patients (volumetric modulated arc therapy, 10 MV, 5 mm leaf width) were included. Prescribed dose to the prostate was 5 × 7 Gy, with a focal tumor boost up to 5 × 10 Gy. MRI-linac treatment plans (intensity modulated radiotherapy, 7 MV, 7 mm leaf width, fixed collimator angle and 1.5 T magnetic field) were calculated. Dose distributions were compared. RESULTS In both conventional and MRI-linac treatment plans, the V35Gy to the whole prostate was >99% in all patients. Mean dose to the gross tumor volume was 45 Gy for conventional and 44 Gy for MRI-linac plans, respectively. Organ at risk doses were met in the majority of plans, except for a rectal V35Gy constraint, which was exceeded in one patient, by 1 cc, for both modalities. The bladder V32Gy and V28Gy constraints were exceeded in two and one patient respectively, for both modalities. CONCLUSION Planning of stereotactic radiotherapy with focal ablative boosting in prostate cancer on a high field MRI-linac is feasible with the current MRI-linac properties, without deterioration of plan quality compared to conventional treatments.
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Affiliation(s)
- Mariska D. den Hartogh
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Hans C.J. de Boer
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | - Jochem Hes
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Uulke A. van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Floris Pos
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Karin Haustermans
- Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium
| | - Tom Depuydt
- Department of Radiation Oncology, University Hospitals Leuven, Leuven, Belgium
| | - Robert Jan Smeenk
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Martina Kunze-Busch
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bas W. Raaymakers
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Linda G.W. Kerkmeijer
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Radiation Oncology, Radboud University Medical Center, Nijmegen, The Netherlands
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van de Schoot AJ, van den Wollenberg W, Carbaat C, de Ruiter P, Nowee ME, Pos F, van Triest B, Sonke JJ, Janssen TM. Evaluation of plan quality in radiotherapy planning with an MR-linac. Phys Imaging Radiat Oncol 2019; 10:19-24. [PMID: 33458263 PMCID: PMC7807609 DOI: 10.1016/j.phro.2019.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/03/2019] [Accepted: 04/09/2019] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND & PURPOSE Clinical introduction of magnetic resonance (MR)-guided radiotherapy involves treatment planning while taking into account machine-specific characteristics. Our aim was to investigate the feasibility of high-quality MR-linac treatment planning for an MR-linac and to benchmark MR-linac plan quality (IMRT) against current clinical practice (VMAT). MATERIALS & METHODS Data of eight rectal and eight prostate cancer patients, who received radiotherapy on a conventional CBCT-integrated linac, were selected. Clinically acquired CTs and associated delineations of target volumes and organs-at-risk (OARs) were used for MR-linac treatment planning in Monaco. To investigate treatment planning software bias 'quasi MR-linac plans' were generated in Pinnacle3 by mimicking MR-linac specific beam characteristics. MR-linac, quasi MR-linac, and clinical plans were compared and differences in target and OAR doses assessed. Differences in plan complexity were determined by the number of segments and monitor units. RESULTS Compared to clinical plans, MR-linac plans showed a statistically significant decrease in plan homogeneity, an increase in PTV Dmean (prostate: 0.6 Gy; rectum: 0.8 Gy) and D1% (prostate: 1.9 Gy; rectum: 2.0 Gy), and increases in OAR dose. Quasi MR-linac plans were comparable to MR-linac plans with respect to OAR dose and plan homogeneity. For rectal cancer an increase was seen in PTV Dmean (0.12 Gy) and D1% (0.5 Gy) compared to regular MR-linac plans. All created plans were clinically equivalent to current clinical practice. CONCLUSIONS This study demonstrates the feasibility of creating high-quality MR-linac treatment plans. The results supported the clinical introduction of an MR-linac.
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Affiliation(s)
| | - Wouter van den Wollenberg
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Casper Carbaat
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Peter de Ruiter
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Marlies E. Nowee
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Floris Pos
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Baukelien van Triest
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Jan-Jakob Sonke
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Tomas M. Janssen
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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