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Hassan SP, de Leon J, Batumalai V, Moutrie Z, Hogan L, Ge Y, Stricker P, Jameson MG. Magnetic resonance guided adaptive post prostatectomy radiotherapy: Accumulated dose comparison of different workflows. J Appl Clin Med Phys 2024; 25:e14253. [PMID: 38394627 PMCID: PMC11005979 DOI: 10.1002/acm2.14253] [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: 05/17/2023] [Revised: 09/26/2023] [Accepted: 12/06/2023] [Indexed: 02/25/2024] Open
Abstract
PURPOSE The aim of this study was to assess the use of magnetic resonance guided adaptive radiotherapy (MRgART) in the post-prostatectomy setting; comparing dose accumulation for our initial seven patients treated with fully adaptive workflow on the Unity MR-Linac (MRL) and with non-adaptive plans generated offline. Additionally, we analyzed toxicity in patients receiving treatment. METHODS Seven patients were treated with MRgART. The prescription was 70-72 Gy in 35-36 fractions. Patients were treated with an adapt to shape (ATS) technique. For each clinically delivered plan, a non-adaptive plan based upon the reference plan was generated and compared to the associated clinically delivered plan. A total of 468 plans were analyzed. Concordance Index of target and Organs at Risk (OARs) for each fraction with reference contours was analyzed. Acute toxicity was then assessed at six-months following completion of treatment with Common Terminology for Adverse Events (CTCAE) Toxicity Criteria. RESULTS A total of 246 fractions were clinically delivered to seven patients; 234 fractions were delivered via MRgART and 12 fractions delivered via a traditional linear accelerator due to machine issues. Pre-treatment reference plans met CTV and OAR criteria. PTV coverage satisfaction was higher in the clinically delivered adaptive plans than non-adaptive comparison plans; 42.93% versus 7.27% respectively. Six-month CTCAE genitourinary and gastrointestinal toxicity was absent in most patients, and mild-to-moderate in a minority of patients (Grade 1 GU toxicity in one patient and Grade 2 GI toxicity in one patient). CONCLUSIONS Daily MRgART treatment consistently met planning criteria. Target volume variability in prostate bed treatment can be mitigated by using MRgART and deliver satisfactory coverage of CTV whilst minimizing dose to adjacent OARs and reducing toxicity.
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Affiliation(s)
- Sean P. Hassan
- GenesisCareSt Vincent's HospitalSydneyNew South WalesAustralia
| | | | - Vikneswary Batumalai
- GenesisCareSt Vincent's HospitalSydneyNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesSydneyNew South WalesAustralia
| | - Zoe Moutrie
- GenesisCareSt Vincent's HospitalSydneyNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesSydneyNew South WalesAustralia
- South Western Sydney Cancer ServicesNew South Wales HealthSydneyAustralia
- Ingham Institute for Applied Medical ResearchSydneyAustralia
| | - Louise Hogan
- GenesisCareSt Vincent's HospitalSydneyNew South WalesAustralia
- GenesisCareMurdochWestern AustraliaAustralia
| | - Yuanyuan Ge
- GenesisCareSt Vincent's HospitalSydneyNew South WalesAustralia
| | - Phillip Stricker
- Faculty of MedicineUniversity of New South WalesSydneyNew South WalesAustralia
- Western Sydney UniversityPenrithNew South WalesAustralia
- St Vincent's Prostate Cancer Research CentreDarlinghurstNew South WalesAustralia
- Garvan Institute, DarlinghurstSydneyNew South WalesAustralia
- University of SydneyCamperdownNew South WalesAustralia
| | - Michael G. Jameson
- GenesisCareSt Vincent's HospitalSydneyNew South WalesAustralia
- Faculty of MedicineUniversity of New South WalesSydneyNew South WalesAustralia
- Centre for Medical Radiation PhysicsUniversity of WollongongWollongongAustralia
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Gao Y, Yoon S, Ma TM, Yang Y, Sheng K, Low DA, Ballas L, Steinberg ML, Kishan AU, Cao M. Intra-fractional geometric and dose/volume metric variations of magnetic resonance imaging-guided stereotactic radiotherapy of prostate bed after radical prostatectomy. Phys Imaging Radiat Oncol 2024; 30:100573. [PMID: 38585371 PMCID: PMC10997948 DOI: 10.1016/j.phro.2024.100573] [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: 11/06/2023] [Revised: 03/22/2024] [Accepted: 03/22/2024] [Indexed: 04/09/2024] Open
Abstract
Background and purpose Magnetic Resonance Imaging (MRI)-guided Stereotactic body radiotherapy (SBRT) treatment to prostate bed after radical prostatectomy has garnered growing interests. The aim of this study is to evaluate intra-fractional anatomic and dose/volume metric variations for patients receiving this treatment. Materials and methods Nineteen patients who received 30-34 Gy in 5 fractions on a 0.35T MR-Linac were included. Pre- and post-treatment MRIs were acquired for each fraction (total of 75 fractions). The Clinical Target Volume (CTV), bladder, rectum, and rectal wall were contoured on all images. Volumetric changes, Hausdorff distance, Mean Distance to Agreement (MDA), and Dice similarity coefficient (DSC) for each structure were calculated. Median value and Interquartile range (IQR) were recorded. Changes in target coverage and Organ at Risk (OAR) constraints were compared and evaluated using Wilcoxon rank sum tests at a significant level of 0.05. Results Bladder had the largest volumetric changes, with a median volume increase of 48.9 % (IQR 28.9-76.8 %) and a median MDA of 5.1 mm (IQR 3.4-7.1 mm). Intra-fractional CTV volume remained stable with a median volume change of 1.2 % (0.0-4.8 %). DSC was 0.97 (IQR 0.94-0.99). For the dose/volume metrics, there were no statistically significant changes observed except for an increase in bladder hotspot and a decrease of bladder V32.5 Gy and mean dose. The CTV V95% changed from 99.9 % (IQR 98.8-100 %) to 99.6 % (IQR 93.9-100 %). Conclusion Despite intra-fractional variations of OARs, CTV coverage remained stable during MRI-guided SBRT treatments for the prostate bed.
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Affiliation(s)
- Yu Gao
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Radiation Oncology, Stanford University, Palo Alto, CA, USA
| | - Stephanie Yoon
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Radiation Oncology, City of Hope, Duarte, CA, USA
| | - Ting Martin Ma
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Radiation Oncology, University of Washington, Seattle, WA, USA
| | - Yingli Yang
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Radiation Oncology, Shanghai Ruijin Hospital, China
| | - Ke Sheng
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
- Department of Radiation Oncology, University of California, San Francisco, San Francisco, CA, USA
| | - Daniel A. Low
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Leslie Ballas
- Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Michael L. Steinberg
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Amar U Kishan
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
| | - Minsong Cao
- Department of Radiation Oncology, University of California, Los Angeles, Los Angeles, CA, USA
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Sritharan K, Akhiat H, Cahill D, Choi S, Choudhury A, Chung P, Diaz J, Dysager L, Hall W, Huddart R, Kerkmeijer LGW, Lawton C, Mohajer J, Murray J, Nyborg CJ, Pos FJ, Rigo M, Schytte T, Sidhom M, Sohaib A, Tan A, van der Voort van Zyp J, Vesprini D, Zelefsky MJ, Tree AC. Development of Prostate Bed Delineation Consensus Guidelines for Magnetic Resonance Image-Guided Radiotherapy and Assessment of Its Effect on Interobserver Variability. Int J Radiat Oncol Biol Phys 2024; 118:378-389. [PMID: 37633499 DOI: 10.1016/j.ijrobp.2023.08.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 08/28/2023]
Abstract
PURPOSE The use of magnetic resonance imaging (MRI) in radiotherapy planning is becoming more widespread, particularly with the emergence of MRI-guided radiotherapy systems. Existing guidelines for defining the prostate bed clinical target volume (CTV) show considerable heterogeneity. This study aimed to establish baseline interobserver variability (IOV) for prostate bed CTV contouring on MRI, develop international consensus guidelines, and evaluate its effect on IOV. METHODS AND MATERIALS Participants delineated the CTV on 3 MRI scans, obtained from the Elekta Unity MR-Linac, as per their normal practice. Radiation oncologist contours were visually examined for discrepancies, and interobserver comparisons were evaluated against simultaneous truth and performance level estimation (STAPLE) contours using overlap metrics (Dice similarity coefficient and Cohen's kappa), distance metrics (mean distance to agreement and Hausdorff distance), and volume measurements. A literature review of postradical prostatectomy local recurrence patterns was performed and presented alongside IOV results to the participants. Consensus guidelines were collectively constructed, and IOV assessment was repeated using these guidelines. RESULTS Sixteen radiation oncologists' contours were included in the final analysis. Visual evaluation demonstrated significant differences in the superior, inferior, and anterior borders. Baseline IOV assessment indicated moderate agreement for the overlap metrics while volume and distance metrics demonstrated greater variability. Consensus for optimal prostate bed CTV boundaries was established during a virtual meeting. After guideline development, a decrease in IOV was observed. The maximum volume ratio decreased from 4.7 to 3.1 and volume coefficient of variation reduced from 40% to 34%. The mean Dice similarity coefficient rose from 0.72 to 0.75 and the mean distance to agreement decreased from 3.63 to 2.95 mm. CONCLUSIONS Interobserver variability in prostate bed contouring exists among international genitourinary experts, although this is lower than previously reported. Consensus guidelines for MRI-based prostate bed contouring have been developed, and this has resulted in an improvement in contouring concordance. However, IOV persists and strategies such as an education program, development of a contouring atlas, and further refinement of the guidelines may lead to additional improvements.
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Affiliation(s)
- Kobika Sritharan
- Royal Marsden NHS Foundation Trust, Sutton, United Kingdom; Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, United Kingdom.
| | | | - Declan Cahill
- Department of Urology, Royal Marsden Hospital NHS Trust, London, United Kingdom
| | - Seungtaek Choi
- Department of Radiation Oncology, MD Anderson Cancer Center, Houston, Texas
| | - Ananya Choudhury
- Christie National Health Service Foundation Trust, Manchester, United Kingdom; University of Manchester, Manchester, United Kingdom
| | - Peter Chung
- Department of Radiation Oncology, Princess Margaret Cancer Centre, University of Toronto, Toronto, Ontario, Canada
| | | | - Lars Dysager
- Department of Oncology, Odense University Hospital, Odense, Denmark
| | - William Hall
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Robert Huddart
- Royal Marsden NHS Foundation Trust, Sutton, United Kingdom; Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, United Kingdom
| | - Linda G W Kerkmeijer
- Department of Radiation Oncology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Colleen Lawton
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | | | - Julia Murray
- Royal Marsden NHS Foundation Trust, Sutton, United Kingdom; Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, United Kingdom
| | | | - Floris J Pos
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Michele Rigo
- Advanced Radiation Oncology Department, IRCCS Sacro Cuore Don Calabria Hospital, Negrar Di Valpolicella, Italy
| | - Tine Schytte
- Department of Oncology, Odense University Hospital, Odense, Denmark; Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mark Sidhom
- Cancer Therapy Centre, Liverpool Hospital, Liverpool, New South Wales, Australia
| | - Aslam Sohaib
- Department of Radiology, Royal Marsden Hospital NHS Trust, Sutton, United Kingdom
| | - Alex Tan
- Sunshine Coast Hospital and Health Service, Queensland, Australia; James Cook University, Townsville, Queensland, Australia
| | | | - Danny Vesprini
- Department of Radiation Oncology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Michael J Zelefsky
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Alison C Tree
- Royal Marsden NHS Foundation Trust, Sutton, United Kingdom; Division of Radiotherapy and Imaging, Institute of Cancer Research, Sutton, United Kingdom
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Chuong MD, Palm RF, Tjong MC, Hyer DE, Kishan AU. Advances in MRI-Guided Radiation Therapy. Surg Oncol Clin N Am 2023; 32:599-615. [PMID: 37182995 DOI: 10.1016/j.soc.2023.02.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Abstract
Image guidance for radiation therapy (RT) has evolved over the last few decades and now is routinely performed using cone-beam computerized tomography (CBCT). Conventional linear accelerators (LINACs) that use CBCT have limited soft tissue contrast, are not able to image the patient's internal anatomy during treatment delivery, and most are not capable of online adaptive replanning. RT delivery systems that use MRI have become available within the last several years and address many of the imaging limitations of conventional LINACs. Herein, the authors review the technical characteristics and advantages of MRI-guided RT as well as emerging clinical outcomes.
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Affiliation(s)
- Michael D Chuong
- Department of Radiation Oncology, Miami Cancer Institute, 8900 North Kendall Drive, Miami, FL 33176, USA.
| | - Russell F Palm
- Department of Radiation Oncology, Moffitt Cancer Center, 12902 USF Magnolia Drive, Tampa, FL 33612, USA
| | - Michael C Tjong
- Department of Radiation Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Daniel E Hyer
- Department of Radiation Oncology, University of Iowa, 200 Hawkins Dr, Iowa City, IA 52242, USA
| | - Amar U Kishan
- Department of Radiation Oncology, University of California Los Angeles, 1338 S Hope Street, Los Angeles, CA 90015, USA
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The Role of Adaptive Planning in Margin-Reduced, MRI-Guided Stereotactic Body Radiotherapy to the Prostate Bed Following Radical Prostatectomy: Post-hoc Analysis of a Phase II Clinical Trial. Radiother Oncol 2023; 183:109631. [PMID: 36934894 DOI: 10.1016/j.radonc.2023.109631] [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: 11/18/2022] [Revised: 03/02/2023] [Accepted: 03/13/2023] [Indexed: 03/19/2023]
Abstract
BACKGROUND AND PURPOSE We examined the interfractional variations of clinical target volumes (CTVs), planning target volumes (PTVs), and organs-at-risk (OARs) in patients receiving MRI-guided stereotactic body radiotherapy (SBRT) to the prostate bed and evaluated the potential role of adaptive planning. MATERIALS AND METHODS 31 patients received 30-34 Gy in five fractions to the prostate bed on a phase II clinical trial. OARs, CTVs, and PTVs were retrospectively contoured on daily pretreatment MRIs (n=155). Geometric comparisons were made between initial planning contours and daily pretreatment contours. Predicted treatment plans for each fraction were evaluated using the following constraints: CTV V95%>93%, PTV V95%>90%, bladder Dmax<36.7Gy, bladder V32.5Gy<35%, rectum Dmax<36.7Gy, rectum V27.5Gy<45%, rectum 32.5Gy<30%, and rectal wall V24Gy<50%. Adaptive planning was simulated for all fractions that failed to meet these criteria. Plans were then re-evaluated. RESULTS Median change in volume was 0.48% for CTV, -24.5% for bladder, and 6.95% for rectum. Median DSC was 0.89 for CTV, 0.79 for bladder, and 0.76 for rectum. 145/155 fractions (93.5%) met CTV V95%>93%. 75/155 fractions (48.4%) failed at least one OAR dose constraint. Overall, 83/155 fractions (53.5%) met criteria for adapting planning. This affected 24/31 patients (77.4%). Following adaptive planning, all fractions met CTV V95%>93% and PTV V95%>90% and 120/155 fractions (77.4%) met all OAR constraints. CONCLUSION Due to significant interfractional variations in anatomy, a majority of fractions failed to meet both target volume and OAR constraints. However, adaptive planning was effective in overcoming these anatomic changes. Adaptive planning should be routinely considered in prostate bed SBRT. This was a post-hoc analysis of the following registered clinical trial: NCT03541850.
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Laughlin BS, Yu NY, Lo S, Duan J, Welchel Z, Tinnon K, Beckett M, Schild SE, Wong WW, Keole SR, Rwigema JCM, Vargas CE, Rong Y. Clinical Practice Evolvement for Post-Operative Prostate Cancer Radiotherapy-Part 2: Feasibility of Margin Reduction for Fractionated Radiation Treatment with Advanced Image Guidance. Cancers (Basel) 2022; 15:cancers15010040. [PMID: 36612040 PMCID: PMC9817842 DOI: 10.3390/cancers15010040] [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: 10/30/2022] [Revised: 12/08/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose: Planning target volume (PTV) expansion for post-prostatectomy radiotherapy is typically ≥5 mm. Recent clinical trials have proved the feasibility of a reduced margin of 2−3 mm for treatments on MRI-linac. We aim to study the minimum PTV margin needed using iterative cone-beam CT (iCBCT) as image guidance on conventional linacs. Materials/Methods: Fourteen patients who received post-prostatectomy irradiation (8 with an endorectal balloon and 6 without a balloon) were included in this study. Treatment was delivered with volumetric modulated radiation therapy (VMAT). Fractional dose delivery was evaluated in 165 treatment fractions. The bladder, rectal wall, femoral heads, and prostate bed clinical tumor volume (CTV) were contoured and verified on daily iCBCT. PTV margins (0 mm, 2 mm, and 4 mm) were evaluated on daily iCBCT. CTV coverage and OAR dose parameters were assessed with each PTV margin. Results: CTV D100% was underdosed with a 0 mm margin in 32% of fractions in comparison with 2 mm (6%) and 4 mm (6%) PTV margin (p ≤ 0.001). CTV D95% > 95% was met in 93−94% fractions for all PTV expansions. CTV D95% > 95% was achieved in more patients with an endorectal balloon than those without: 0 mm—90/91 (99%) vs. 63/74 (85%); 2 mm—90/91 (99%) vs. 65/75 (87%); 4 mm—90/90 (100%) vs. 63/73 (86%). There was no difference in absolute median change in CTV D95% (0.32%) for 0-, 2-, and 4 mm margins. The maximum dose remained under 108% for 100% (0 mm), 97% (2 mm), and 98% (4 mm) of images. Rectal wall maximum dose remained under 108% for 100% (0 mm), 100% (2 mm), and 98% (4 mm) of images. Conclusions: With high-quality iCBCT image guidance, PTV margin accounting for inter-fractional uncertainties can be safely reduced for post-prostatectomy radiotherapy. For fractionated radiotherapy, an isotropic expansion of 2 mm and 4 mm may be considered for margin expansion with and without the endorectal balloon. Future application for margin reduction needs to be further evaluated and considered with the advent of shorter post-prostatectomy radiation courses.
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Affiliation(s)
- Brady S. Laughlin
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - Nathan Y. Yu
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - Stephanie Lo
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - Jingwei Duan
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
- Department of Radiation Oncology, University of Kentucky, Lexington, KY 40506, USA
| | - Zachary Welchel
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
- Department of Nuclear and Radiological Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Katie Tinnon
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - Mason Beckett
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - Steven E. Schild
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - William W. Wong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | - Sameer R. Keole
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
| | | | - Carlos E. Vargas
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
- Correspondence: (C.E.V.); (Y.R.)
| | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic, Phoenix, AZ 85259, USA
- Correspondence: (C.E.V.); (Y.R.)
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Laughlin BS, Lo S, Vargas CE, DeWees TA, Van der Walt C, Tinnon K, Beckett M, Hobbis D, Schild SE, Wong WW, Keole SR, Rwigema JCM, Yu NY, Clouser E, Rong Y. Clinical Practice Evolvement for Post-Operative Prostate Cancer Radiotherapy-Part 1: Consistent Organs at Risk Management with Advanced Image Guidance. Cancers (Basel) 2022; 15:cancers15010016. [PMID: 36612013 PMCID: PMC9817677 DOI: 10.3390/cancers15010016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 12/07/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose: Post-operative prostate cancer patients are treated with full bladder instruction and the use of an endorectal balloon (ERB). We reassessed the efficacy of this practice based on daily image guidance and dose delivery using high-quality iterative reconstructed cone-beam CT (iCBCT). Methods: Fractional dose delivery was calculated on daily iCBCT for 314 fractions from 14 post-operative prostate patients (8 with and 6 without ERB) treated with volumetric modulated radiotherapy (VMAT). All patients were positioned using novel iCBCT during image guidance. The bladder, rectal wall, femoral heads, and prostate bed clinical tumor volume (CTV) were contoured and verified on daily iCBCT. The dose-volume parameters of the contoured organs at risk (OAR) and CTV coverage were assessed for the clinical impact of daily bladder volume variations and the use of ERB. Minimum bladder volume was studied, and a straightforward bladder instruction was explored for easy clinical adoption. Results: A “minimum bladder” contour, the overlap between the original bladder contour and a 15 mm anterior and superior expansion from prostate bed PTV, was confirmed to be effective in identifying cases that might fail a bladder constraint of V65% <60%. The average difference between the maximum and minimum bladder volumes for each patient was 277.1 mL. The daily bladder volumes varied from 62.4 to 590.7 mL and ranged from 29 to 286% of the corresponding planning bladder volume. The bladder constraint of V65% <60% was met in almost all fractions (98%). CTVs (D90%, D95%, and D98%) remained well-covered regardless of the absolute bladder volume daily variation or the presence of the endorectal balloon. Patients with an endorectal balloon showed smaller variation but a higher average maximum rectal wall dose (D0.03mL: 104.3% of the prescription) compared to patients without (103.3%). Conclusions: A “minimum bladder” contour was determined that can be easily generated and followed to ensure sufficient bladder sparing. Further analysis and validation are needed to confirm the utility of the minimal bladder contour. Accurate dose delivery can be achieved for prostate bed target coverage and OAR sparing with or without the use of ERB.
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Affiliation(s)
- Brady S. Laughlin
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Stephanie Lo
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Carlos E. Vargas
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Todd A. DeWees
- Department of Qualitative Health Sciences, Section of Biostatistics, Mayo Clinic Arizona, 13400 E Shea Blvd, Scottsdale, AZ 85259, USA
| | - Charles Van der Walt
- Department of Qualitative Health Sciences, Section of Biostatistics, Mayo Clinic Arizona, 13400 E Shea Blvd, Scottsdale, AZ 85259, USA
| | - Katie Tinnon
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Mason Beckett
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Dean Hobbis
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Steven E. Schild
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - William W. Wong
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Sameer R. Keole
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Jean-Claude M. Rwigema
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Nathan Y. Yu
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Edward Clouser
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
| | - Yi Rong
- Department of Radiation Oncology, Mayo Clinic, 5881 E Mayo Blvd., Phoenix, AZ 85054, USA
- Correspondence:
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Morgan HE, Wang K, Yan Y, Desai N, Hannan R, Chambers E, Cai B, Lin MH, Sher DJ, Wang J, Wang AZ, Jiang S, Timmerman R, Park CJ, Garant A. Preliminary Evaluation of PTV Margins for Online Adaptive Radiation Therapy of the Prostatic Fossa. Pract Radiat Oncol 2022:S1879-8500(22)00366-6. [PMID: 36509197 DOI: 10.1016/j.prro.2022.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/07/2022] [Accepted: 11/11/2022] [Indexed: 12/14/2022]
Abstract
PURPOSE In modern trials, traditional planning target volume (PTV) margins for postoperative prostate radiation therapy have been large (7-10 mm) to account for both daily changes in patient positioning and target deformation. With daily adaptive radiation therapy, these interfractional changes could be minimized, potentially reducing the margins required for treatment and improving adjacent normal-tissue dosimetry. METHODS AND MATERIALS A single-center retrospective study was conducted from March 2021 to November 2021. Patients receiving conventionally fractionated postoperative radiation therapy (PORT) for prostate cancer with pretreatment and posttreatment cone beam computed tomography (CBCT) imaging (pre-CBCT and post-CBCT, respectively) were included (248 paired images). Pretreatment and posttreatment clinical target volumes (pre-CTVs and post-CTVs) were contoured by a single observer on all CBCTs and verified by a second observer. Motion was calculated from pre-CTV to that of the post-CTV, and predicted margins were calculated with van Herk's formula. Adequate coverage of the proposed planning target volume (PTV) margin expansions (pre-PTV) were verified by determining overlap with post-CTV. In a smaller cohort (25 paired images), dosimetric changes with the proposed online adaptive margins were compared with conventional plans in the Ethos emulator environment. RESULTS The estimated margins predicted to achieve ≥95% CTV coverage for 90% of the population were 1.6 mm, 2.0 mm, and 2.2 mm (x-, y-, and z -xes, respectively), with 95% of the absolute region of interest displacement being within 1.9 mm, 2.8 mm, and 2.1 mm. After symmetrically expanding all pre-CTVs by 3 mm, the percentage of paired images achieving ≥95% CTV coverage was 97.1%. When comparing adaptive plans (3-mm margins) with scheduled plans (7-mm margins), rectum dosimetry significantly improved, with an average relative reduction in V40Gy[cc] of 59.2% and V65Gy[cc] of 79.5% (where V40Gy and V65Gy are defined as the volumes receiving 40 Gy and 65 Gy or higher dose, respectively). CONCLUSIONS Online daily adaptive radiation therapy could significantly decrease PTV margins for prostatic PORT and improve rectal dosimetry, with a symmetrical expansion of 3 mm achieving excellent coverage in this cohort. These results need to be validated in a larger prospective cohort.
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Affiliation(s)
- Howard E Morgan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Radiation Oncology, CARTI Cancer Center, Little Rock, Arkansas
| | - Kai Wang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas; Medical Artificial Intelligence and Automation (MAIA) Laboratory, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Yulong Yan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Neil Desai
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Raquibul Hannan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Eric Chambers
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Bin Cai
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mu-Han Lin
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - David J Sher
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jing Wang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas; Medical Artificial Intelligence and Automation (MAIA) Laboratory, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Andrew Z Wang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Steve Jiang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas; Medical Artificial Intelligence and Automation (MAIA) Laboratory, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Robert Timmerman
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Chunjoo Justin Park
- Department of Radiation Oncology, Mayo Clinic-Jacksonville, Jacksonville, Florida.
| | - Aurelie Garant
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, Texas.
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Rammohan N, Randall JW, Yadav P. History of Technological Advancements towards MR-Linac: The Future of Image-Guided Radiotherapy. J Clin Med 2022; 11:jcm11164730. [PMID: 36012969 PMCID: PMC9409689 DOI: 10.3390/jcm11164730] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/27/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
Image-guided radiotherapy (IGRT) enables optimal tumor targeting and sparing of organs-at-risk, which ultimately results in improved outcomes for patients. Magnetic resonance imaging (MRI) revolutionized diagnostic imaging with its superior soft tissue contrast, high spatiotemporal resolution, and freedom from ionizing radiation exposure. Over the past few years there has been burgeoning interest in MR-guided radiotherapy (MRgRT) to overcome current challenges in X-ray-based IGRT, including but not limited to, suboptimal soft tissue contrast, lack of efficient daily adaptation, and incremental exposure to ionizing radiation. In this review, we present an overview of the technologic advancements in IGRT that led to MRI-linear accelerator (MRL) integration. Our report is organized in three parts: (1) a historical timeline tracing the origins of radiotherapy and evolution of IGRT, (2) currently available MRL technology, and (3) future directions and aspirations for MRL applications.
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10
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Magnetic Resonance Guided Radiotherapy for Head and Neck Cancers. J Clin Med 2022; 11:jcm11051388. [PMID: 35268479 PMCID: PMC8911481 DOI: 10.3390/jcm11051388] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/23/2022] [Accepted: 02/28/2022] [Indexed: 11/16/2022] Open
Abstract
Radiotherapy is an integral component of head/neck squamous cell carcinomas (HNSCCs) treatment, and technological developments including advances in image-guided radiotherapy over the past decades have offered improvements in the technical treatment of these cancers. Integration of magnetic resonance imaging (MRI) into image guidance through the development of MR-guided radiotherapy (MRgRT) offers further potential for refinement of the techniques by which HNSCCs are treated. This article provides an overview of the literature supporting the current use of MRgRT for HNSCC, challenges with its use, and developing research areas.
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11
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Proposal and Evaluation of a Physician-Free, Real-Time On-Table Adaptive Radiotherapy (PF-ROAR) Workflow for the MRIdian MR-Guided LINAC. J Clin Med 2022; 11:jcm11051189. [PMID: 35268279 PMCID: PMC8911471 DOI: 10.3390/jcm11051189] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/19/2022] [Accepted: 02/21/2022] [Indexed: 02/04/2023] Open
Abstract
With the implementation of MR-LINACs, real-time adaptive radiotherapy has become a possibility within the clinic. However, the process of adapting a patient’s plan is time consuming and often requires input from the entire clinical team, which translates to decreased throughput and limited patient access. In this study, the authors propose and simulate a workflow to address these inefficiencies in staffing and patient throughput. Two physicians, three radiation therapists (RTT), and a research fellow each adapted bladder and bowel contours for 20 fractions from 10 representative patient plans. Contouring ability was compared via calculation of a Dice Similarity Index (DSI). The DSI for bladder and bowel based on each potential physician–therapist pair, as well as an inter-physician comparison, exhibited good overlap amongst all comparisons (p = 0.868). Plan quality was compared through calculation of the conformity index (CI), as well as an evaluation of the plan’s dose to a ‘gold standard’ set of structures. Overall, non-physician plans passed 91.2% of the time. Of the eight non-physician plans that failed their clinical evaluation, six also failed their evaluation against the ‘gold standard’. Another two plans that passed their clinical evaluation subsequently failed in their evaluation against the ‘gold standard’. Thus, the PF-ROAR process has a success rate of 97.5%, with 78/80 plans correctly adapted to the gold standard or halted at treatment. These findings suggest that a physician-free workflow can be well tolerated provided RTTs continue to develop knowledge of MR anatomy and careful attention is given to understanding the complexity of the plan prior to treatment.
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