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Siddiq S, Murray V, Tyagi N, Borman P, Gui C, Crane C, Wu C, Otazo R. MR signature matching (MRSIGMA) implementation for true real-time free-breathing volumetric imaging with sub-200 ms latency on an MR-Linac. Magn Reson Med 2024; 92:1162-1176. [PMID: 38576131 PMCID: PMC11209806 DOI: 10.1002/mrm.30097] [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: 11/14/2023] [Revised: 02/20/2024] [Accepted: 03/14/2024] [Indexed: 04/06/2024]
Abstract
PURPOSE Develop a true real-time implementation of MR signature matching (MRSIGMA) for free-breathing 3D MRI with sub-200 ms latency on the Elekta Unity 1.5T MR-Linac. METHODS MRSIGMA was implemented on an external computer with a network connection to the MR-Linac. Stack-of-stars with partial kz sampling was used to accelerate data acquisition and ReconSocket was employed for simultaneous data transmission. Movienet network computed the 4D MRI motion dictionary and correlation analysis was used for signature matching. A programmable 4D MRI phantom was utilized to evaluate MRSIGMA with respect to a ground-truth translational motion reference. In vivo validation was performed on patients with pancreatic cancer, where 15 patients were employed to train Movienet and 7 patients to test the real-time implementation of MRSIGMA. Dice coefficients between real-time MRSIGMA and a retrospectively computed 4D reference were used to evaluate motion tracking performance. RESULTS Motion dictionary was computed in under 5 s. Signature acquisition and matching presented 173 ms latency on the phantom and 193 ms on patients. MRSIGMA presented a mean error of 1.3-1.6 mm for all phantom experiments, which was below the 2 mm acquisition resolution along the motion direction. The Dice coefficient over time between MRSIGMA and reference contours was 0.88 ± 0.02 (GTV), 0.87 ± 0.02(duodenum-stomach), and 0.78 ± 0.02(small bowel), demonstrating high motion tracking performance for both tumor and organs at risk. CONCLUSION The real-time implementation of MRSIGMA enabled true real-time free-breathing 3D MRI with sub-200 ms imaging latency on a clinical MR-Linac system, which can be used for treatment monitoring, adaptive radiotherapy and dose accumulation mapping in tumors affected by respiratory motion.
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Affiliation(s)
- Saad Siddiq
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Victor Murray
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Pim Borman
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Chengcheng Gui
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Christopher Crane
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Can Wu
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ricardo Otazo
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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Jiang L, Ye Y, Feng Z, Liu W, Cao Y, Zhao X, Zhu X, Zhang H. Stereotactic body radiation therapy for the primary tumor and oligometastases versus the primary tumor alone in patients with metastatic pancreatic cancer. Radiat Oncol 2024; 19:111. [PMID: 39160547 PMCID: PMC11334573 DOI: 10.1186/s13014-024-02493-8] [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: 01/10/2024] [Accepted: 07/19/2024] [Indexed: 08/21/2024] Open
Abstract
BACKGROUND Local therapies may benefit patients with oligometastatic cancer. However, there were limited data about pancreatic cancer. Here, we compared the efficacy and safety of stereotactic body radiation therapy (SBRT) to the primary tumor and all oligometastases with SBRT to the primary tumor alone in patients with metastatic pancreatic cancer. METHODS A retrospective review of patients with synchronous oligometastatic pancreatic cancer (up to 5 lesions) receiving SBRT to all lesions (including all oligometastases and the primary tumor) were performed. Another comparable group of patients with similar baseline characteristics, including metastatic burden, SBRT doses, and chemotherapy regimens, receiving SBRT to the primary tumor alone were identified. The primary endpoint was overall survival (OS). The secondary endpoints were progression frees survival (PFS), polyprogression free survival (PPFS) and adverse events. RESULTS There were 59 and 158 patients receiving SBRT to all lesions and to the primary tumor alone. The median OS of patients with SBRT to all lesions and the primary tumor alone was 10.9 months (95% CI 10.2-11.6 months) and 9.3 months (95% CI 8.8-9.8 months) (P < 0.001). The median PFS of two groups was 6.5 months (95% CI 5.6-7.4 months) and 4.1 months (95% CI 3.8-4.4 months) (P < 0.001). The median PPFS of two groups was 9.8 months (95% CI 8.9-10.7 months) and 7.8 months (95% CI 7.2-8.4 months) (P < 0.001). Additionally, 14 (23.7%) and 32 (20.2%) patients in two groups had grade 3 or 4 treatment-related toxicity. CONCLUSIONS SBRT to all oligometastases and the primary tumor in patients with pancreatic cancer may improve survival, which needs prospective verification.
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Affiliation(s)
- Lingong Jiang
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China
| | - Yusheng Ye
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China
| | - Zhiru Feng
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China
| | - Wenyu Liu
- Department of Hepatobiliary and Pancreatic Surgery, Changhai Hospital affiliated to Naval Medical University, Shanghai, China
| | - Yangsen Cao
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China
| | - Xianzhi Zhao
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China
| | - Xiaofei Zhu
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China.
| | - Huojun Zhang
- Department of Radiation Oncology, Changhai Hospital affiliated to Naval Medical University, 168 Changhai Road, Shanghai, 200433, China.
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Grimbergen G, Eijkelenkamp H, Snoeren LM, Bahij R, Bernchou U, van der Bijl E, Heerkens HD, Binda S, Ng SS, Bouchart C, Paquier Z, Brown K, Khor R, Chuter R, Freear L, Dunlop A, Mitchell RA, Erickson BA, Hall WA, Godoy Scripes P, Tyagi N, de Leon J, Tran C, Oh S, Renz P, Shessel A, Taylor E, Intven MP, Meijer GJ. Treatment planning for MR-guided SBRT of pancreatic tumors on a 1.5 T MR-Linac: A global consensus protocol. Clin Transl Radiat Oncol 2024; 47:100797. [PMID: 38831754 PMCID: PMC11145226 DOI: 10.1016/j.ctro.2024.100797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 05/17/2024] [Accepted: 05/17/2024] [Indexed: 06/05/2024] Open
Abstract
Background and purpose Treatment planning for MR-guided stereotactic body radiotherapy (SBRT) for pancreatic tumors can be challenging, leading to a wide variation of protocols and practices. This study aimed to harmonize treatment planning by developing a consensus planning protocol for MR-guided pancreas SBRT on a 1.5 T MR-Linac. Materials and methods A consortium was founded of thirteen centers that treat pancreatic tumors on a 1.5 T MR-Linac. A phased planning exercise was conducted in which centers iteratively created treatment plans for two cases of pancreatic cancer. Each phase was followed by a meeting where the instructions for the next phase were determined. After three phases, a consensus protocol was reached. Results In the benchmarking phase (phase I), substantial variation between the SBRT protocols became apparent (for example, the gross tumor volume (GTV) D99% ranged between 36.8 - 53.7 Gy for case 1, 22.6 - 35.5 Gy for case 2). The next phase involved planning according to the same basic dosimetric objectives, constraints, and planning margins (phase II), which led to a large degree of harmonization (GTV D99% range: 47.9-53.6 Gy for case 1, 33.9-36.6 Gy for case 2). In phase III, the final consensus protocol was formulated in a treatment planning system template and again used for treatment planning. This not only resulted in further dosimetric harmonization (GTV D99% range: 48.2-50.9 Gy for case 1, 33.5-36.0 Gy for case 2) but also in less variation of estimated treatment delivery times. Conclusion A global consensus protocol has been developed for treatment planning for MR-guided pancreatic SBRT on a 1.5 T MR-Linac. Aside from harmonizing the large variation in the current clinical practice, this protocol can provide a starting point for centers that are planning to treat pancreatic tumors on MR-Linac systems.
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Affiliation(s)
- Guus Grimbergen
- Department of Radiation Oncology, University Medical Center Utrecht, The Netherlands
| | - Hidde Eijkelenkamp
- Department of Radiation Oncology, University Medical Center Utrecht, The Netherlands
| | - Louk M.W. Snoeren
- Department of Radiation Oncology, University Medical Center Utrecht, The Netherlands
| | - Rana Bahij
- Department of Oncology, Odense University Hospital, Denmark
| | - Uffe Bernchou
- Department of Oncology, Odense University Hospital, Denmark
- Department of Clinical Research, University of Southern Denmark, Denmark
| | - Erik van der Bijl
- Department of Radiation Oncology, Radboudumc, Nijmegen, The Netherlands
| | - Hanne D. Heerkens
- Department of Radiation Oncology, Radboudumc, Nijmegen, The Netherlands
| | - Shawn Binda
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Sylvia S.W. Ng
- Department of Radiation Oncology, Odette Cancer Centre, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Christelle Bouchart
- Department of Radiation Oncology, HUB Institut Jules Bordet, Brussels, Belgium
| | - Zelda Paquier
- Department of Radiation Oncology, HUB Institut Jules Bordet, Brussels, Belgium
| | - Kerryn Brown
- Radiation Oncology, ONJ Centre, Austin Health, Heidelberg, Victoria, Australia
| | - Richard Khor
- Radiation Oncology, ONJ Centre, Austin Health, Heidelberg, Victoria, Australia
| | | | | | - Alex Dunlop
- The Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK
| | - Robert Adam Mitchell
- The Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London, UK
| | - Beth A. Erickson
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - William A. Hall
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Paola Godoy Scripes
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Charles Tran
- GenesisCare, Darlinghurst, New South Wales, Australia
| | - Seungjong Oh
- Division of Radiation Oncology, Allegheny General Hospital, Pittsburgh, PA, USA
| | - Paul Renz
- Division of Radiation Oncology, Allegheny General Hospital, Pittsburgh, PA, USA
| | - Andrea Shessel
- Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada
| | - Edward Taylor
- Princess Margaret Cancer Center, University Health Network, Toronto, Ontario, Canada
| | - Martijn P.W. Intven
- Department of Radiation Oncology, University Medical Center Utrecht, The Netherlands
| | - Gert J. Meijer
- Department of Radiation Oncology, University Medical Center Utrecht, The Netherlands
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Saúde-Conde R, El Ghali B, Navez J, Bouchart C, Van Laethem JL. Total Neoadjuvant Therapy in Localized Pancreatic Cancer: Is More Better? Cancers (Basel) 2024; 16:2423. [PMID: 39001485 PMCID: PMC11240662 DOI: 10.3390/cancers16132423] [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: 05/15/2024] [Revised: 06/24/2024] [Accepted: 06/24/2024] [Indexed: 07/16/2024] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) poses a significant challenge in oncology due to its advanced stage upon diagnosis and limited treatment options. Surgical resection, the primary curative approach, often results in poor long-term survival rates, leading to the exploration of alternative strategies like neoadjuvant therapy (NAT) and total neoadjuvant therapy (TNT). While NAT aims to enhance resectability and overall survival, there appears to be potential for improvement, prompting consideration of alternative neoadjuvant strategies integrating full-dose chemotherapy (CT) and radiotherapy (RT) in TNT approaches. TNT integrates chemotherapy and radiotherapy prior to surgery, potentially improving margin-negative resection rates and enabling curative resection for locally advanced cases. The lingering question: is more always better? This article categorizes TNT strategies into six main groups based on radiotherapy (RT) techniques: (1) conventional chemoradiotherapy (CRT), (2) the Dutch PREOPANC approach, (3) hypofractionated ablative intensity-modulated radiotherapy (HFA-IMRT), and stereotactic body radiotherapy (SBRT) techniques, which further divide into (4) non-ablative SBRT, (5) nearly ablative SBRT, and (6) adaptive ablative SBRT. A comprehensive analysis of the literature on TNT is provided for both borderline resectable pancreatic cancer (BRPC) and locally advanced pancreatic cancer (LAPC), with detailed sections for each.
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Affiliation(s)
- Rita Saúde-Conde
- Digestive Oncology Department, Hôpitaux Universitaires de Bruxelles (HUB), Université Libre de Bruxelles, 1070 Brussels, Belgium;
| | - Benjelloun El Ghali
- Department of Radiation Oncology, Hôpitaux Universitaires de Bruxelles (HUB), Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium; (B.E.G.); (C.B.)
| | - Julie Navez
- Department of Abdominal Surgery and Transplantation, Hôpitaux Universitaires de Bruxelles (HUB), Hopital Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium;
| | - Christelle Bouchart
- Department of Radiation Oncology, Hôpitaux Universitaires de Bruxelles (HUB), Institut Jules Bordet, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium; (B.E.G.); (C.B.)
| | - Jean-Luc Van Laethem
- Digestive Oncology Department, Hôpitaux Universitaires de Bruxelles (HUB), Université Libre de Bruxelles, 1070 Brussels, Belgium;
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Kurokawa M, Tsuneda M, Abe K, Ikeda Y, Kanazawa A, Saito M, Kodate A, Harada R, Yokota H, Watanabe M, Uno T. A pilot study on interobserver variability in organ-at-risk contours in magnetic resonance imaging-guided online adaptive radiotherapy for pancreatic cancer. Front Oncol 2024; 14:1335623. [PMID: 38800394 PMCID: PMC11116709 DOI: 10.3389/fonc.2024.1335623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 04/15/2024] [Indexed: 05/29/2024] Open
Abstract
Purpose Differences in the contours created during magnetic resonance imaging-guided online adaptive radiotherapy (MRgOART) affect dose distribution. This study evaluated the interobserver error in delineating the organs at risk (OARs) in patients with pancreatic cancer treated with MRgOART. Moreover, we explored the effectiveness of drugs that could suppress peristalsis in restraining intra-fractional motion by evaluating OAR visualization in multiple patients. Methods This study enrolled three patients who underwent MRgOART for pancreatic cancer. The study cohort was classified into three conditions based on the MRI sequence and butylscopolamine administration (Buscopan): 1, T2 imaging without butylscopolamine administration; 2, T2 imaging with butylscopolamine administration; and 3, multi-contrast imaging with butylscopolamine administration. Four blinded observers visualized the OARs (stomach, duodenum, small intestine, and large intestine) on MR images acquired during the initial and final MRgOART sessions. The contour was delineated on a slice area of ±2 cm surrounding the planning target volume. The dice similarity coefficient (DSC) was used to evaluate the contour. Moreover, the OARs were visualized on both MR images acquired before and after the contour delineation process during MRgOART to evaluate whether peristalsis could be suppressed. The DSC was calculated for each OAR. Results Interobserver errors in the OARs (stomach, duodenum, small intestine, large intestine) for the three conditions were 0.636, 0.418, 0.676, and 0.806; 0.725, 0.635, 0.762, and 0.821; and 0.841, 0.677, 0.762, and 0.807, respectively. The DSC was higher in all conditions with butylscopolamine administration compared with those without it, except for the stomach in condition 2, as observed in the last session of MR image. The DSCs for OARs (stomach, duodenum, small intestine, large intestine) extracted before and after contouring were 0.86, 0.78, 0.88, and 0.87; 0.97, 0.94, 0.90, and 0.94; and 0.94, 0.86, 0.89, and 0.91 for conditions 1, 2, and 3, respectively. Conclusion Butylscopolamine effectively reduced interobserver error and intra-fractional motion during the MRgOART treatment.
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Affiliation(s)
- Marie Kurokawa
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Masato Tsuneda
- Department of Radiation Oncology, MR Linac ART Division, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Kota Abe
- Department of Radiation Oncology, MR Linac ART Division, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Yohei Ikeda
- Department of Radiology, Chiba University Hospital, Chuo-ku, Chiba, Japan
| | - Aki Kanazawa
- Department of Radiology, Chiba University Hospital, Chuo-ku, Chiba, Japan
| | - Makoto Saito
- Department of Radiology, Chiba University Hospital, Chuo-ku, Chiba, Japan
| | - Asuka Kodate
- Department of Radiology, Chiba University Hospital, Chuo-ku, Chiba, Japan
| | - Rintaro Harada
- Department of Radiology, Chiba University Hospital, Chuo-ku, Chiba, Japan
| | - Hajime Yokota
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Miho Watanabe
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
| | - Takashi Uno
- Diagnostic Radiology and Radiation Oncology, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan
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6
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Dee EC, Ng VC, O’Reilly EM, Wei AC, Lobaugh SM, Varghese AM, Zinovoy M, Romesser PB, Wu AJ, Hajj C, Cuaron JJ, Khalil DN, Park W, Yu KH, Zhang Z, Drebin JA, Jarnagin WR, Crane CH, Reyngold M. Salvage Ablative Radiotherapy for Isolated Local Recurrence of Pancreatic Adenocarcinoma following Definitive Surgery. J Clin Med 2024; 13:2631. [PMID: 38731159 PMCID: PMC11084663 DOI: 10.3390/jcm13092631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Introduction: The rate of isolated locoregional recurrence after surgery for pancreatic adenocarcinoma (PDAC) approaches 25%. Ablative radiation therapy (A-RT) has improved outcomes for locally advanced disease in the primary setting. We sought to evaluate the outcomes of salvage A-RT for isolated locoregional recurrence and examine the relationship between subsequent patterns of failure, radiation dose, and treatment volume. Methods: We conducted a retrospective analysis of all consecutive participants who underwent A-RT for an isolated locoregional recurrence of PDAC after prior surgery at our institution between 2016 and 2021. Treatment consisted of ablative dose (BED10 98-100 Gy) to the gross disease with an additional prophylactic low dose (BED10 < 50 Gy), with the elective volume covering a 1.5 cm isotropic expansion around the gross disease and the circumference of the involved vessels. Local and locoregional failure (LF and LRF, respectively) estimated by the cumulative incidence function with competing risks, distant metastasis-free and overall survival (DMFS and OS, respectively) estimated by the Kaplan-Meier method, and toxicities scored by CTCAE v5.0 are reported. Location of recurrence was mapped to the dose region on the initial radiation plan. Results: Among 65 participants (of whom two had two A-RT courses), the median age was 67 (range 37-87) years, 36 (55%) were male, and 53 (82%) had undergone pancreaticoduodenectomy with a median disease-free interval to locoregional recurrence of 16 (range, 6-71) months. Twenty-seven participants (42%) received chemotherapy prior to A-RT. With a median follow-up of 35 months (95%CI, 26-56 months) from diagnosis of recurrence, 24-month OS and DMFS were 57% (95%CI, 46-72%) and 22% (95%CI, 14-37%), respectively, while 24-month cumulative incidence of in-field LF and total LRF were 28% (95%CI, 17-40%) and 36% (95%CI 24-48%), respectively. First failure after A-RT was distant in 35 patients (53.8%), locoregional in 12 patients (18.5%), and synchronous distant and locoregional in 10 patients (15.4%). Most locoregional failures occurred in elective low-dose volumes. Acute and chronic grade 3-4 toxicities were noted in 1 (1.5%) and 5 patients (7.5%), respectively. Conclusions: Salvage A-RT achieves favorable OS and local control outcomes in participants with an isolated locoregional recurrence of PDAC after surgical resection. Consideration should be given to extending high-dose fields to include adjacent segments of at-risk vessels beyond direct contact with the gross disease.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Marsha Reyngold
- Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; (E.C.D.); (V.C.N.); (C.H.C.)
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7
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Edwards S, Luzzara M, Dell’Acqua V, Christodouleas J. The Radiation Therapy Technology Evidence Matrix: a framework to visualize evidence development for innovations in radiation therapy. Front Oncol 2024; 14:1351610. [PMID: 38628665 PMCID: PMC11018969 DOI: 10.3389/fonc.2024.1351610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/19/2024] [Indexed: 04/19/2024] Open
Abstract
Clinical evidence is crucial in enabling the judicious adoption of technological innovations in radiation therapy (RT). Pharmaceutical evidence development frameworks are not useful for understanding how technical advances are maturing. In this paper, we introduce a new framework, the Radiation Therapy Technology Evidence Matrix (rtTEM), that helps visualize how the clinical evidence supporting new technologies is developing. The matrix is a unique 2D model based on the R-IDEAL clinical evaluation framework. It can be applied to clinical hypothesis testing trials, as well as publications reporting clinical treatment. We present the rtTEM and illustrate its application, using emerging and mature RT technologies as examples. The model breaks down the type of claim along the vertical axis and the strength of the evidence for that claim on the horizontal axis, both of which are inherent in clinical hypothesis testing. This simplified view allows for stakeholders to understand where the evidence is and where it is heading. Ultimately, the value of an innovation is typically demonstrated through superiority studies, which we have divided into three key categories - administrative, toxicity and control, to enable more detailed visibility of evidence development in that claim area. We propose the rtTEM can be used to track evidence development for new interventions in RT. We believe it will enable researchers and sponsors to identify gaps in evidence and to further direct evidence development. Thus, by highlighting evidence looked for by key policy decision makers, the rtTEM will support wider, timely patient access to high value technological advances.
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Affiliation(s)
- Sarah Edwards
- Medical Affairs and Clinical Research, Elekta AB, Stockholm, Sweden
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8
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Daamen LA, Parikh PJ, Hall WA. The Use of MR-Guided Radiation Therapy for Pancreatic Cancer. Semin Radiat Oncol 2024; 34:23-35. [PMID: 38105090 DOI: 10.1016/j.semradonc.2023.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
The introduction of online adaptive magnetic resonance (MR)-guided radiation therapy (RT) has enabled safe treatment of pancreatic cancer with ablative doses. The aim of this review is to provide a comprehensive overview of the current literature on the use and clinical outcomes of MR-guided RT for treatment of pancreatic cancer. Relevant outcomes included toxicity, tumor response, survival and quality of life. The results of these studies support further investigation of the effectiveness of ablative MR-guided SBRT as a low-toxic, minimally-invasive therapy for localized pancreatic cancer in prospective clinical trials.
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Affiliation(s)
- Lois A Daamen
- Imaging & Oncology Division, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands
| | - Parag J Parikh
- Department of Radiation Oncology, Henry Ford Medical Center, Henry Ford Health System, Detroit, MI
| | - William A Hall
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI.
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9
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Grimbergen G, Hackett SL, van Ommen F, van Lier ALHMW, Borman PTS, Meijers LTC, de Groot-van Breugel EN, de Boer JCJ, Raaymakers BW, Intven MPW, Meijer GJ. Gating and intrafraction drift correction on a 1.5 T MR-Linac: Clinical dosimetric benefits for upper abdominal tumors. Radiother Oncol 2023; 189:109932. [PMID: 37778533 DOI: 10.1016/j.radonc.2023.109932] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/18/2023] [Accepted: 09/23/2023] [Indexed: 10/03/2023]
Abstract
This work reports on the first seven patients treated with gating and baseline drift correction on the high-field MR-Linac system. Dosimetric analysis showed that the active motion management system improved congruence to the planned dose, efficiently mitigating detrimental effects of intrafraction motion in the upper abdomen.
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Affiliation(s)
- Guus Grimbergen
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands.
| | - Sara L Hackett
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | - Fasco van Ommen
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | | | - Pim T S Borman
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | - Lieke T C Meijers
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | | | - Johannes C J de Boer
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | - Bas W Raaymakers
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | - Martijn P W Intven
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
| | - Gert J Meijer
- Department of Radiation Oncology, University Medical Center Utrecht, the Netherlands
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10
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Eijkelenkamp H, Grimbergen G, Daamen LA, Heerkens HD, van de Ven S, Mook S, Meijer GJ, Molenaar IQ, van Santvoort HC, Paulson E, Erickson BA, Verkooijen HM, Hall WA, Intven MPW. Clinical outcomes after online adaptive MR-guided stereotactic body radiotherapy for pancreatic tumors on a 1.5 T MR-linac. Front Oncol 2023; 13:1040673. [PMID: 37854684 PMCID: PMC10579578 DOI: 10.3389/fonc.2023.1040673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 08/18/2023] [Indexed: 10/20/2023] Open
Abstract
Introduction Online adaptive magnetic resonance-guided radiotherapy (MRgRT) is a promising treatment modality for pancreatic cancer and is being employed by an increasing number of centers worldwide. However, clinical outcomes have only been reported on a small scale, often from single institutes and in the context of clinical trials, in which strict patient selection might limit generalizability of outcomes. This study presents clinical outcomes of a large, international cohort of patients with (peri)pancreatic tumors treated with online adaptive MRgRT. Methods We evaluated clinical outcomes and treatment details of patients with (peri)pancreatic tumors treated on a 1.5 Tesla (T) MR-linac in two large-volume treatment centers participating in the prospective MOMENTUM cohort (NCT04075305). Treatments were evaluated through schematics, dosage, delivery strategies, and success rates. Acute toxicity was assessed until 3 months after MRgRT started, and late toxicity from 3-12 months of follow-up (FU). The EORTC QLQ-C30 questionnaire was used to evaluate the quality of life (QoL) at baseline and 3 months of FU. Furthermore, we used the Kaplan-Meier analysis to calculate the cumulative overall survival. Results A total of 80 patients were assessed with a median FU of 8 months (range 1-39 months). There were 34 patients who had an unresectable primary tumor or were medically inoperable, 29 who had an isolated local recurrence, and 17 who had an oligometastasis. A total of 357 of the 358 fractions from all hypofractionated schemes were delivered as planned. Grade 3-4 acute toxicity occurred in 3 of 59 patients (5%) with hypofractionated MRgRT and grade 3-4 late toxicity in 5 of 41 patients (12%). Six patients died within 3 months after MRgRT; in one of these patients, RT attribution could not be ruled out as cause of death. The QLQ-C30 global health status remained stable from baseline to 3 months FU (70.5 at baseline, median change of +2.7 [P = 0.5]). The 1-year cumulative overall survival for the entire cohort was 67%, and that for the primary tumor group was 66%. Conclusion Online adaptive MRgRT for (peri)pancreatic tumors on a 1.5 T MR-Linac could be delivered as planned, with low numbers of missed fractions. In addition, treatments were associated with limited grade 3-4 toxicity and a stable QoL at 3 months of FU.
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Affiliation(s)
- Hidde Eijkelenkamp
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Guus Grimbergen
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Lois A. Daamen
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Hanne D. Heerkens
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
- Department of Radiotherapy, Radboud University Medical Center, Nijmegen, Netherlands
| | - Saskia van de Ven
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Stella Mook
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Gert J. Meijer
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
| | - Izaak Q. Molenaar
- Department of Surgery, Regional Academic Cancer Center Utrecht, Utrecht, Netherlands
| | | | - Eric Paulson
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Beth Ann Erickson
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | | | - William Adrian Hall
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Martijn P. W. Intven
- Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
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Wu C, Murray V, Siddiq SS, Tyagi N, Reyngold M, Crane C, Otazo R. Real-time 4D MRI using MR signature matching (MRSIGMA) on a 1.5T MR-Linac system. Phys Med Biol 2023; 68:10.1088/1361-6560/acf3cc. [PMID: 37619588 PMCID: PMC10513779 DOI: 10.1088/1361-6560/acf3cc] [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: 05/11/2023] [Accepted: 08/24/2023] [Indexed: 08/26/2023]
Abstract
Objective. To develop real-time 4D MRI using MR signature matching (MRSIGMA) for volumetric motion imaging in patients with pancreatic cancer on a 1.5T MR-Linac system.Approach. Two consecutive MRI scans with 3D golden-angle radial stack-of-stars acquisitions were performed on ten patients with inoperable pancreatic cancer. The complete first scan (905 angles) was used to compute a 4D motion dictionary including ten pairs of 3D motion images and signatures. The second scan was used for real-time imaging, where each angle (275 ms) was processed separately to match it to one of the dictionary entries. The complete second scan was also used to compute a 4D reference to assess motion tracking performance.Dicecoefficients of the gross tumor volume (GTV) and two organs-at-risk (duodenum-stomach and small bowel) were calculated between signature matching and reference. In addition, volume changes, displacements, center of mass shifts, andDicescores over time were calculated to characterize motion.Main results. Total imaging latency of MRSIGMA (acquisition + matching) was less than 300 ms. TheDicecoefficients were 0.87 ± 0.06 (GTV), 0.86 ± 0.05 (duodenum-stomach), and 0.85 ± 0.05 (small bowel), which indicate high accuracy (high mean value) and low uncertainty (low standard deviation) of MRSIGMA for real-time motion tracking. The center of mass shift was 3.1 ± 2.0 mm (GTV), 5.3 ± 3.0 mm (duodenum-stomach), and 3.4 ± 1.5 mm (small bowel). TheDicescores over time (0.97 ± [0.01-0.03]) were similarly high for MRSIGMA and reference scans in all the three contours.Significance. This work demonstrates the feasibility of real-time 4D MRI using MRSIGMA for volumetric motion tracking on a 1.5T MR-Linac system. The high accuracy and low uncertainty of real-time MRSIGMA is an essential step towards continuous treatment adaptation of tumors affected by real-time respiratory motion and could ultimately improve treatment safety by optimizing ablative dose delivery near gastrointestinal organs.
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Affiliation(s)
- Can Wu
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Victor Murray
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Syed S. Siddiq
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Marsha Reyngold
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Christopher Crane
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY
| | - Ricardo Otazo
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY
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12
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Reyngold M, Karam SD, Hajj C, Wu AJ, Cuaron J, Lobaugh S, Yorke ED, Dickinson S, Jones B, Vinogradskiy Y, Shukla-Dave A, Do RKG, Sigel C, Zhang Z, Crane CH, Goodman KA. Phase 1 Dose Escalation Study of SBRT Using 3 Fractions for Locally Advanced Pancreatic Cancer. Int J Radiat Oncol Biol Phys 2023; 117:53-63. [PMID: 36918130 PMCID: PMC11229378 DOI: 10.1016/j.ijrobp.2023.03.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 02/24/2023] [Accepted: 03/02/2023] [Indexed: 03/14/2023]
Abstract
PURPOSE The optimal dose and fractionation of stereotactic body radiation therapy (SBRT) for locally advanced pancreatic cancer (LAPC) have not been defined. Single-fraction SBRT was associated with more gastrointestinal toxicity, so 5-fraction regimens have become more commonly employed. We aimed to determine the safety and maximally tolerated dose of 3-fraction SBRT for LAPC. METHODS AND MATERIALS Two parallel phase 1 dose escalation trials were conducted from 2016 to 2019 at Memorial Sloan Kettering Cancer Center and University of Colorado. Patients with histologically confirmed LAPC without distant progression after at least 2 months of induction chemotherapy were eligible. Patients received 3-fraction linear accelerator-based SBRT at 3 dose levels, 27, 30, and 33 Gy, following a modified 3+3 design. Dose-limiting toxicity, defined as grade ≥3 gastrointestinal toxicity within 90 days, was scored by National Cancer Institute Common Terminology Criteria for Adverse Events, version 4. The secondary endpoints included cumulative incidence of local failure (LF) and distant metastasis (DM), as well as progression-free and overall survival PFS and OS, respectively, toxicity, and quality of life (QoL) using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (QLQ-C30) and the pancreatic cancer-specific QLQ-PAN26 questionnaire. RESULTS Twenty-four consecutive patients were enrolled (27 Gy: 9, 30 Gy: 8, 33 Gy: 7). The median (range) age was 67 (52-79) years, and 12 (50%) had a head/uncinate tumor location, with a median tumor size of 3.8 (1.1-11) cm and CA19-9 of 60 (1-4880) U/mL. All received chemotherapy for a median of 4 (1.4-10) months. There were no grade ≥3 toxicities. Two-year rates (95% confidence interval) of LF, DM, PFS, and OS were 31.7% (8.6%-54.8%), 70.2% (49.7%-90.8%), 20.8% (4.6%-37.1%), and 29.2% (11.0%-47.4%), respectively. Three- and 6-month QoL assessment showed no detriment. CONCLUSIONS For select patients with LAPC, dose escalation to 33 Gy in 3 fractions resulted in no dose-limiting toxicities, no detriments to QoL, and disease outcomes comparable with conventional RT. Further exploration of SBRT schemes to maximize tumor control while enabling efficient integration with systemic therapy is warranted.
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Affiliation(s)
- Marsha Reyngold
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York.
| | - Sana D Karam
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Carla Hajj
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Abraham J Wu
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - John Cuaron
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Stephanie Lobaugh
- Department of Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ellen D Yorke
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Shannan Dickinson
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Bernard Jones
- Department of Radiation Oncology, University of Colorado School of Medicine, Aurora, Colorado
| | - Yevgeniy Vinogradskiy
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Amita Shukla-Dave
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York; Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Richard Kinh Gian Do
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Carlie Sigel
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Zhigang Zhang
- Department of Biostatistics, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Christopher H Crane
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Karyn A Goodman
- Department of Radiation Oncology, Icahn School of Medicine at Mount Sinai, New York, New York
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Ejlsmark MW, Schytte T, Bernchou U, Bahij R, Weber B, Mortensen MB, Pfeiffer P. Radiotherapy for Locally Advanced Pancreatic Adenocarcinoma-A Critical Review of Randomised Trials. Curr Oncol 2023; 30:6820-6837. [PMID: 37504359 PMCID: PMC10378124 DOI: 10.3390/curroncol30070499] [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: 06/16/2023] [Revised: 07/08/2023] [Accepted: 07/14/2023] [Indexed: 07/29/2023] Open
Abstract
Pancreatic cancer is rising as one of the leading causes of cancer-related death worldwide. Patients often present with advanced disease, limiting curative treatment options and therefore making management of the disease difficult. Systemic chemotherapy has been an established part of the standard treatment in patients with both locally advanced and metastatic pancreatic cancer. In contrast, the use of radiotherapy has no clear defined role in the treatment of these patients. With the evolving imaging and radiation techniques, radiation could become a plausible intervention. In this review, we give an overview over the available data regarding radiotherapy, chemoradiation, and stereotactic body radiation therapy. We performed a systematic search of Embase and the PubMed database, focusing on studies involving locally advanced pancreatic cancer (or non-resectable pancreatic cancer) and radiotherapy without any limitation for the time of publication. We included randomised controlled trials involving patients with locally advanced pancreatic cancer, including radiotherapy, chemoradiation, or stereotactic body radiation therapy. The included articles represented mainly small patient groups and had a high heterogeneity regarding radiation delivery and modality. This review presents conflicting results concerning the addition of radiation and modality in the treatment regimen. Further research is needed to improve outcomes and define the role of radiation therapy in pancreatic cancer.
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Affiliation(s)
- Mathilde Weisz Ejlsmark
- Department of Oncology, Odense University Hospital, 5000 Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Tine Schytte
- Department of Oncology, Odense University Hospital, 5000 Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Uffe Bernchou
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
- Laboratory of Radiation Physics, Odense University Hospital, 5000 Odense, Denmark
| | - Rana Bahij
- Department of Oncology, Odense University Hospital, 5000 Odense, Denmark
| | - Britta Weber
- Department of Oncology, Aarhus University Hospital, 8200 Aarhus, Denmark
- Danish Centre of Particle Therapy, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Michael Bau Mortensen
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
- Department of Surgery, Odense University Hospital, 5000 Odense, Denmark
| | - Per Pfeiffer
- Department of Oncology, Odense University Hospital, 5000 Odense, Denmark
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
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14
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Grimbergen G, Eijkelenkamp H, van Vulpen JK, van de Ven S, Raaymakers BW, Intven MP, Meijer GJ. Feasibility of online radial magnetic resonance imaging for adaptive radiotherapy of pancreatic tumors. Phys Imaging Radiat Oncol 2023; 26:100434. [PMID: 37034029 PMCID: PMC10074242 DOI: 10.1016/j.phro.2023.100434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 03/22/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023] Open
Abstract
Background and purpose Online adaptive magnetic resonance (MR)-guided treatment planning for pancreatic tumors on 1.5T systems typically employs Cartesian 3D T 2w magnetic resonance imaging (MRI). The main disadvantage of this sequence is that respiratory motion results in substantial blurring in the abdomen, which can hamper delineation accuracy. This study investigated the use of two motion-robust radial MRI sequences as main delineation scan for pancreatic MR-guided radiotherapy. Materials and methods Twelve patients with pancreatic tumors were imaged with a 3D T 2w scan, a Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction (PROPELLER) scan (partially overlapping strips), and a 3D Vane scan (stack-of-stars), on a 1.5T MR-Linac under abdominal compression. The scans were assessed by three radiation oncologists for their suitability for online adaptive delineation. A quantitative comparison was made for gradient entropy and the effect of motion on apparent target position. Results The PROPELLER scans were selected as first preference in 56% of the cases, the 3D T 2w in 42% and the 3D Vane in 3%. PROPELLER scans sometimes contained a large interslice variation which would have compromised delineation. Gradient entropy was significantly higher in 3D T 2w patient scans. The apparent target position was more sensitive to motion amplitude in the PROPELLER scans, but substantial offsets did not occur under 10 mm peak-to-peak. Conclusion PROPELLER MRI may be a superior imaging sequence for pancreatic MRgRT compared to standard Cartesian sequences. The large interslice variation should be mitigated through further sequence optimization before PROPELLER can be adopted for online treatment adaptation.
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15
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Feasibility of delivered dose reconstruction for MR-guided SBRT of pancreatic tumors with fast, real-time 3D cine MRI. Radiother Oncol 2023; 182:109506. [PMID: 36736589 DOI: 10.1016/j.radonc.2023.109506] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND PURPOSE In MR-guided SBRT of pancreatic cancer, intrafraction motion is typically monitored with (interleaved) 2D cine MRI. However, tumor surroundings are often not fully captured in these images, and motion might be distorted by through-plane movement. In this study, the feasibility of highly accelerated 3D cine MRI to reconstruct the delivered dose during MR-guided SBRT was assessed. MATERIALS AND METHODS A 3D cine MRI sequence was developed for fast, time-resolved 4D imaging, featuring a low spatial resolution that allows for rapid volumetric imaging at 430 ms. The 3D cines were acquired during the entire beam-on time of 23 fractions of online adaptive MR-guided SBRT for pancreatic tumors on a 1.5 T MR-Linac. A 3D deformation vector field (DVF) was extracted for every cine dynamic using deformable image registration. Next, these DVFs were used to warp the partial dose delivered in the time interval between consecutive cine acquisitions. The warped dose plans were summed to obtain a total delivered dose. The delivered dose was also calculated under various motion correction strategies. Key DVH parameters of the GTV, duodenum, small bowel and stomach were extracted from the delivered dose and compared to the planned dose. The uncertainty of the calculated DVFs was determined with the inverse consistency error (ICE) in the high-dose regions. RESULTS The mean (SD) relative (ratio delivered/planned) D99% of the GTV was 0.94 (0.06), and the mean (SD) relative D0.5cc of the duodenum, small bowel, and stomach were respectively 0.98 (0.04), 1.00 (0.07), and 0.98 (0.06). In the fractions with the lowest delivered tumor coverage, it was found that significant lateral drifts had occurred. The DVFs used for dose warping had a low uncertainty with a mean (SD) ICE of 0.65 (0.07) mm. CONCLUSION We employed a fast, real-time 3D cine MRI sequence for dose reconstruction in the upper abdomen, and demonstrated that accurate DVFs, acquired directly from these images, can be used for dose warping. The reconstructed delivered dose showed only a modest degradation of tumor coverage, mostly attainable to baseline drifts. This emphasizes the need for motion monitoring and development of intrafraction treatment adaptation solutions, such as baseline drift corrections.
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