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Keall PJ, Sawant A, Berbeco RI, Booth JT, Cho B, Cerviño LI, Cirino E, Dieterich S, Fast MF, Greer PB, Munck Af Rosenschöld P, Parikh PJ, Poulsen PR, Santanam L, Sherouse GW, Shi J, Stathakis S. AAPM Task Group 264: The safe clinical implementation of MLC tracking in radiotherapy. Med Phys 2021; 48:e44-e64. [PMID: 33260251 DOI: 10.1002/mp.14625] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 11/11/2020] [Accepted: 11/18/2020] [Indexed: 12/25/2022] Open
Abstract
The era of real-time radiotherapy is upon us. Robotic and gimbaled linac tracking are clinically established technologies with the clinical realization of couch tracking in development. Multileaf collimators (MLCs) are a standard equipment for most cancer radiotherapy systems, and therefore MLC tracking is a potentially widely available technology. MLC tracking has been the subject of theoretical and experimental research for decades and was first implemented for patient treatments in 2013. The AAPM Task Group 264 Safe Clinical Implementation of MLC Tracking in Radiotherapy Report was charged to proactively provide the broader radiation oncology community with (a) clinical implementation guidelines including hardware, software, and clinical indications for use, (b) commissioning and quality assurance recommendations based on early user experience, as well as guidelines on Failure Mode and Effects Analysis, and (c) a discussion of potential future developments. The deliverables from this report include: an explanation of MLC tracking and its historical development; terms and definitions relevant to MLC tracking; the clinical benefit of, clinical experience with and clinical implementation guidelines for MLC tracking; quality assurance guidelines, including example quality assurance worksheets; a clinical decision pathway, future outlook and overall recommendations.
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Affiliation(s)
- Paul J Keall
- ACRF Image X Institute, The University of Sydney Faculty of Medicine and Health, Sydney, NSW, 2006, Australia
| | - Amit Sawant
- Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ross I Berbeco
- Radiation Oncology, Brigham and Women's Hospital, Boston, MA, 02115, USA
| | - Jeremy T Booth
- Radiation Oncology, Royal North Shore Hospital, St Leonards, 2065, NSW, Australia.,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, 2006, Australia
| | - Byungchul Cho
- Radiation Oncology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, 138-736, Republic of Korea
| | - Laura I Cerviño
- Radiation Medicine & Applied Sciences, Radiation Oncology PET/CT Center, UC San Diego, LA Jolla, CA, 92093-0865, USA.,Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065-6007, USA
| | - Eileen Cirino
- Lahey Health and Medical Center, Burlington, MA, 01805, USA
| | - Sonja Dieterich
- Department of Radiation Oncology, UC Davis Medical Center, Sacramento, CA, 95618, USA
| | - Martin F Fast
- Department of Radiotherapy, University Medical Center Utrecht, 3584 CX, Utrecht, The Netherlands
| | - Peter B Greer
- Calvary Mater Newcastle, Newcastle, NSW, 2310, Australia
| | - Per Munck Af Rosenschöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - Parag J Parikh
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Department of Radiation Oncology, Henry Ford Hospital, Detroit, MI, 48202, USA
| | - Per Rugaard Poulsen
- Department of Oncology and Danish Center for Particle Therapy, Aarhus University Hospital, 8200, Aarhus, Denmark
| | - Lakshmi Santanam
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, 63110, USA.,Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, 10065-6007, USA
| | | | - Jie Shi
- Sun Nuclear Corp, Melbourne, FL, 32940, USA
| | - Sotirios Stathakis
- University of Texas Health San Antonio Cancer Center, San Antonio, TX, 78229, USA
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Poulsen PR, Murtaza G, Worm ES, Ravkilde T, O'Brien R, Grau C, Høyer M, Keall P. Simulated multileaf collimator tracking for stereotactic liver radiotherapy guided by kilovoltage intrafraction monitoring: Dosimetric gain and target overdose trends. Radiother Oncol 2020; 144:93-100. [DOI: 10.1016/j.radonc.2019.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 10/14/2019] [Accepted: 11/06/2019] [Indexed: 11/26/2022]
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Caillet V, O'Brien R, Moore D, Poulsen P, Pommer T, Colvill E, Sawant A, Booth J, Keall P. Technical Note: In silico and experimental evaluation of two leaf-fitting algorithms for MLC tracking based on exposure error and plan complexity. Med Phys 2019; 46:1814-1820. [PMID: 30719723 DOI: 10.1002/mp.13425] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 01/13/2019] [Accepted: 01/14/2019] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Multileaf collimator (MLC) tracking is being clinically pioneered to continuously compensate for thoracic and pelvic motion during radiotherapy. The purpose of this work was to characterize the performance of two MLC leaf-fitting algorithms, direct optimization and piecewise optimization, for real-time motion compensation with different plan complexity and tumor trajectories. METHODS To test the algorithms, both in silico and phantom experiments were performed. The phantom experiments were performed on a Trilogy Varian linac and a HexaMotion programmable motion platform. High and low modulation VMAT plans for lung and prostate cancer cases were used along with eight patient-measured organ-specific trajectories. For both MLC leaf-fitting algorithms, the plans were run with their corresponding patient trajectories. To compare algorithms, the average exposure errors, i.e., the difference in shape between ideal and fitted MLC leaves by the algorithm, plan complexity and system latency of each experiment were calculated. RESULTS Comparison of exposure errors for the in silico and phantom experiments showed minor differences between the two algorithms. The average exposure errors for in silico experiments with low/high plan complexity were 0.66/0.88 cm2 for direct optimization and 0.66/0.88 cm2 for piecewise optimization, respectively. The average exposure errors for the phantom experiments with low/high plan complexity were 0.73/1.02 cm2 for direct and 0.73/1.02 cm2 for piecewise optimization, respectively. The measured latency for the direct optimization was 226 ± 10 ms and for the piecewise algorithm was 228 ± 10 ms. In silico and phantom exposure errors quantified for each treatment plan demonstrated that the exposure errors from the high plan complexity (0.96 cm2 mean, 2.88 cm2 95% percentile) were all significantly different from the low plan complexity (0.70 cm2 mean, 2.18 cm2 95% percentile) (P < 0.001, two-tailed, Mann-Whitney statistical test). CONCLUSIONS The comparison between the two leaf-fitting algorithms demonstrated no significant differences in exposure errors, neither in silico nor with phantom experiments. This study revealed that plan complexity impacts the overall exposure errors significantly more than the difference between the algorithms.
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Affiliation(s)
- Vincent Caillet
- Northern Sydney Cancer Centre, Sydney, NSW, Australia.,ACRF Image X Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Ricky O'Brien
- ACRF Image X Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Douglas Moore
- Beyond Center for Fundamental Concepts in Science, Arizona State University, Tempe, AZ, USA
| | | | - Tobias Pommer
- Unit of Radiotherapy Physics and Engineering, Karolinska University Hospital, Solna, Sweden
| | - Emma Colvill
- Northern Sydney Cancer Centre, Sydney, NSW, Australia.,ACRF Image X Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Amit Sawant
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jeremy Booth
- Northern Sydney Cancer Centre, Sydney, NSW, Australia.,ACRF Image X Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Paul Keall
- ACRF Image X Institute, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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Lydiard S, Caillet V, Ipsen S, O’Brien R, Blanck O, Poulsen PR, Booth J, Keall P. Investigating multi-leaf collimator tracking in stereotactic arrhythmic radioablation (STAR) treatments for atrial fibrillation. ACTA ACUST UNITED AC 2018; 63:195008. [DOI: 10.1088/1361-6560/aadf7c] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Toftegaard J, Keall PJ, O'Brien R, Ruan D, Ernst F, Homma N, Ichiji K, Poulsen PR. Potential improvements of lung and prostate MLC tracking investigated by treatment simulations. Med Phys 2018; 45:2218-2229. [DOI: 10.1002/mp.12868] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/07/2018] [Accepted: 03/07/2018] [Indexed: 12/25/2022] Open
Affiliation(s)
- Jakob Toftegaard
- Department of Oncology; Aarhus University Hospital; 8000 Aarhus C Denmark
| | - Paul J. Keall
- Radiation Physics Laboratory; Sydney Medical School; University of Sydney; Sydney New South Wales 2006 Australia
| | - Ricky O'Brien
- Radiation Physics Laboratory; Sydney Medical School; University of Sydney; Sydney New South Wales 2006 Australia
| | - Dan Ruan
- Department of Radiation Oncology; University of California; Los Angeles CA 90095 USA
| | - Floris Ernst
- Institute for Robotics and Cognitive Systems; University of Lübeck; Lübeck 23562 Germany
| | - Noriyasu Homma
- Department of Radiological Imaging and Informatics; Tohoku University Graduate School of Medicine; Sendai 980-8579 Japan
| | - Kei Ichiji
- Department of Radiological Imaging and Informatics; Tohoku University Graduate School of Medicine; Sendai 980-8579 Japan
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Murtaza G, Toftegaard J, Khan EU, Poulsen PR. Volumetric modulated arc therapy with dynamic collimator rotation for improved multileaf collimator tracking of the prostate. Radiother Oncol 2017; 122:109-115. [DOI: 10.1016/j.radonc.2016.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 10/31/2016] [Accepted: 11/03/2016] [Indexed: 12/01/2022]
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Crijns W, Defraene G, Van Herck H, Depuydt T, Haustermans K, Maes F, Van den Heuvel F. Potential benefits of dosimetric VMAT tracking verified with 3D film measurements. Med Phys 2016; 43:2162. [DOI: 10.1118/1.4945024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Falk M, Pommer T, Keall P, Korreman S, Persson G, Poulsen P, Munck af Rosenschöld P. Motion management during IMAT treatment of mobile lung tumors--a comparison of MLC tracking and gated delivery. Med Phys 2015; 41:101707. [PMID: 25281946 DOI: 10.1118/1.4896024] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To compare real-time dynamic multileaf collimator (MLC) tracking, respiratory amplitude and phase gating, and no compensation for intrafraction motion management during intensity modulated arc therapy (IMAT). METHODS Motion management with MLC tracking and gating was evaluated for four lung cancer patients. The IMAT plans were delivered to a dosimetric phantom mounted onto a 3D motion phantom performing patient-specific lung tumor motion. The MLC tracking system was guided by an optical system that used stereoscopic infrared (IR) cameras and five spherical reflecting markers attached to the dosimetric phantom. The gated delivery used a duty cycle of 35% and collected position data using an IR camera and two reflecting markers attached to a marker block. RESULTS The average gamma index failure rate (2% and 2 mm criteria) was <0.01% with amplitude gating for all patients, and <0.1% with phase gating and <3.7% with MLC tracking for three of the four patients. One of the patients had an average failure rate of 15.1% with phase gating and 18.3% with MLC tracking. With no motion compensation, the average gamma index failure rate ranged from 7.1% to 46.9% for the different patients. Evaluation of the dosimetric error contributions showed that the gated delivery mainly had errors in target localization, while MLC tracking also had contributions from MLC leaf fitting and leaf adjustment. The average treatment time was about three times longer with gating compared to delivery with MLC tracking (that did not prolong the treatment time) or no motion compensation. For two of the patients, the different motion compensation techniques allowed for approximately the same margin reduction but for two of the patients, gating enabled a larger reduction of the margins than MLC tracking. CONCLUSIONS Both gating and MLC tracking reduced the effects of the target movements, although the gated delivery showed a better dosimetric accuracy and enabled a larger reduction of the margins in some cases. MLC tracking did not prolong the treatment time compared to delivery with no motion compensation while gating had a considerably longer delivery time. In a clinical setting, the optical monitoring of the patients breathing would have to be correlated to the internal movements of the tumor.
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Affiliation(s)
- Marianne Falk
- Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen DK-2100, Denmark and Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Tobias Pommer
- Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen DK-2100, Denmark and Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
| | - Paul Keall
- Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney NSW 2006, Australia
| | - Stine Korreman
- Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen DK-2100, Denmark; Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark; and Department of Science, Systems and Models, Roskilde University, Roskilde DK-4000, Denmark
| | - Gitte Persson
- Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen DK-2100, Denmark
| | - Per Poulsen
- Department of Oncology, Aarhus University Hospital, Aarhus DK-8000, Denmark and Institute of Clinical Medicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Per Munck af Rosenschöld
- Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen DK-2100, Denmark and Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark
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Bowen SR, Nyflot MJ, Herrmann C, Groh CM, Meyer J, Wollenweber SD, Stearns CW, Kinahan PE, Sandison GA. Imaging and dosimetric errors in 4D PET/CT-guided radiotherapy from patient-specific respiratory patterns: a dynamic motion phantom end-to-end study. Phys Med Biol 2015; 60:3731-46. [PMID: 25884892 DOI: 10.1088/0031-9155/60/9/3731] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Effective positron emission tomography / computed tomography (PET/CT) guidance in radiotherapy of lung cancer requires estimation and mitigation of errors due to respiratory motion. An end-to-end workflow was developed to measure patient-specific motion-induced uncertainties in imaging, treatment planning, and radiation delivery with respiratory motion phantoms and dosimeters. A custom torso phantom with inserts mimicking normal lung tissue and lung lesion was filled with [(18)F]FDG. The lung lesion insert was driven by six different patient-specific respiratory patterns or kept stationary. PET/CT images were acquired under motionless ground truth, tidal breathing motion-averaged (3D), and respiratory phase-correlated (4D) conditions. Target volumes were estimated by standardized uptake value (SUV) thresholds that accurately defined the ground-truth lesion volume. Non-uniform dose-painting plans using volumetrically modulated arc therapy were optimized for fixed normal lung and spinal cord objectives and variable PET-based target objectives. Resulting plans were delivered to a cylindrical diode array at rest, in motion on a platform driven by the same respiratory patterns (3D), or motion-compensated by a robotic couch with an infrared camera tracking system (4D). Errors were estimated relative to the static ground truth condition for mean target-to-background (T/Bmean) ratios, target volumes, planned equivalent uniform target doses, and 2%-2 mm gamma delivery passing rates. Relative to motionless ground truth conditions, PET/CT imaging errors were on the order of 10-20%, treatment planning errors were 5-10%, and treatment delivery errors were 5-30% without motion compensation. Errors from residual motion following compensation methods were reduced to 5-10% in PET/CT imaging, <5% in treatment planning, and <2% in treatment delivery. We have demonstrated that estimation of respiratory motion uncertainty and its propagation from PET/CT imaging to RT planning, and RT delivery under a dose painting paradigm is feasible within an integrated respiratory motion phantom workflow. For a limited set of cases, the magnitude of errors was comparable during PET/CT imaging and treatment delivery without motion compensation. Errors were moderately mitigated during PET/CT imaging and significantly mitigated during RT delivery with motion compensation. This dynamic motion phantom end-to-end workflow provides a method for quality assurance of 4D PET/CT-guided radiotherapy, including evaluation of respiratory motion compensation methods during imaging and treatment delivery.
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Affiliation(s)
- S R Bowen
- Department of Radiation Oncology, University of Washington School of Medicine, Seattle, WA, USA. Department of Radiology, University of Washington School of Medicine, Seattle, WA, USA
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Glitzner M, Crijns SPM, de Senneville BD, Lagendijk JJW, Raaymakers BW. On the suitability of Elekta’s Agility 160 MLC for tracked radiation delivery: closed-loop machine performance. Phys Med Biol 2015; 60:2005-17. [DOI: 10.1088/0031-9155/60/5/2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ravkilde T, Keall PJ, Grau C, Høyer M, Poulsen PR. Time-resolved dose distributions to moving targets during volumetric modulated arc therapy with and without dynamic MLC tracking. Med Phys 2014; 40:111723. [PMID: 24320431 DOI: 10.1118/1.4826161] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The highly conformal doses delivered by volumetric modulated arc therapy (VMAT) may be compromised by intrafraction target motion. Although dynamic multileaf collimator (DMLC) tracking can mitigate the dosimetric impact of motion on the accumulated dose, residual errors still exist. The purpose of this study was to investigate the temporal evolution of dose errors throughout VMAT treatments delivered with and without DMLC tracking. METHODS Tracking experiments were performed on a linear accelerator connected to prototype DMLC tracking software. A three-axis motion stage reproduced representative clinical trajectories of four lung tumors and four prostates. For each trajectory, two VMAT treatment plans (low and high modulation) were delivered with and without DMLC tracking as well as to a static phantom for reference. Dose distributions were measured continuously at 72 Hz using a dosimeter with biplanar diode arrays. During tracking, the MLC leaves were continuously refitted to the 3D target position measured by an electromagnetic transponder at 30 Hz. The dosimetric errors caused in the 32 motion experiments were quantified by a time-resolved 3%/3 mm γ-test. The erroneously exposed areas in treatment beam's eye view (BEV) caused by inadequate real-time MLC adaptation were calculated and compared with the time-resolved γ failure rates. RESULTS The transient γ failure rate was on average 16.8% without tracking and 5.3% with tracking. The γ failure rate correlated well with the erroneously exposed areas in BEV (mean of Pearson r = 0.83, p < 0.001). For the final accumulated doses, the mean γ failure rate was 17.9% without tracking and 1.0% with tracking. With tracking the transient dose errors tended to cancel out resulting in the low mean γ failure rate for the accumulated doses. CONCLUSIONS Time-resolved measurements allow pinpointing of transient errors in dose during VMAT delivery as well as monitoring of erroneous dose evolution in key target positions. The erroneously exposed area in BEV was shown to be a good indicator of errors in the dose distribution during treatment delivery.
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Affiliation(s)
- Thomas Ravkilde
- Department of Oncology, Aarhus University Hospital, 8000 Aarhus C, Denmark and Institute of Clinical Medicine, Aarhus University, 8200 Aarhus N, Denmark
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Pommer T, Falk M, Poulsen PR, Keall PJ, O'Brien RT, Munck af Rosenschöld P. The impact of leaf width and plan complexity on DMLC tracking of prostate intensity modulated arc therapy. Med Phys 2014; 40:111717. [PMID: 24320425 DOI: 10.1118/1.4824434] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Intensity modulated arc therapy (IMAT) is commonly used to treat prostate cancer. The purpose of this study was to evaluate the impact of leaf width and plan complexity on dynamic multileaf collimator (DMLC) tracking for prostate motion management during IMAT treatments. METHODS Prostate IMAT plans were delivered with either a high-definition MLC (HDMLC) or a Millennium MLC (M-MLC) (0.25 and 0.50 cm central leaf width, respectively), with and without DMLC tracking, to a dosimetric phantom that reproduced four prostate motion traces. The plan complexity was varied by applying leaf position constraints during plan optimization. A subset of the M-MLC plans was converted for delivery with the HDMLC, isolating the effect of the different leaf widths. The gamma index was used for evaluation. Tracking errors caused by target localization, leaf fitting, and leaf adjustment were analyzed. RESULTS The gamma pass rate was significantly improved with DMLC tracking compared to no tracking (p < 0.001). With DMLC tracking, the average gamma index pass rate was 98.6% (range 94.8%-100%) with the HDMLC and 98.1% (range 95.4%-99.7%) with the M-MLC, using 3%, 3 mm criteria and the planned dose as reference. The corresponding pass rates without tracking were 87.6% (range 76.2%-94.7%) and 91.1% (range 81.4%-97.6%), respectively. Decreased plan complexity improved the pass rate when static target measurements were used as reference, but not with the planned dose as reference. The main cause of tracking errors was leaf fitting errors, which were decreased by 42% by halving the leaf width. CONCLUSIONS DMLC tracking successfully compensated for the prostate motion. The finer leaf width of the HDMLC improved the tracking accuracy compared to the M-MLC. The tracking improvement with limited plan complexity was small and not discernible when using the planned dose as reference.
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Affiliation(s)
- Tobias Pommer
- Department of Radiation Oncology (Radiation Medicine Research Center), Rigshospitalet, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark and Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
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Cole A, Hanna G, Jain S, O'Sullivan J. Motion Management for Radical Radiotherapy in Non-small Cell Lung Cancer. Clin Oncol (R Coll Radiol) 2014; 26:67-80. [DOI: 10.1016/j.clon.2013.11.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 09/23/2013] [Accepted: 09/24/2013] [Indexed: 11/28/2022]
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Pommer T, Falk M, Poulsen PR, Keall PJ, O'Brien RT, Petersen PM, Munck af Rosenschöld P. Dosimetric benefit of DMLC tracking for conventional and sub-volume boosted prostate intensity-modulated arc radiotherapy. Phys Med Biol 2013; 58:2349-61. [PMID: 23492899 DOI: 10.1088/0031-9155/58/7/2349] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study investigated the dosimetric impact of uncompensated motion and motion compensation with dynamic multileaf collimator (DMLC) tracking for prostate intensity modulated arc therapy. Two treatment approaches were investigated; a conventional approach with a uniform radiation dose to the target volume and an intraprostatic lesion (IPL) boosted approach with an increased dose to a subvolume of the prostate. The impact on plan quality of optimizations with a leaf position constraint, which limited the distance between neighbouring adjacent MLC leaves, was also investigated. Deliveries were done with and without DMLC tracking on a linear acceleration with a high-resolution MLC. A cylindrical phantom containing two orthogonal diode arrays was used for dosimetry. A motion platform reproduced six patient-derived prostate motion traces, with the average displacement ranging from 1.0 to 8.9 mm during the first 75 s. A research DMLC tracking system was used for real-time motion compensation with optical monitoring for position input. The gamma index was used for evaluation, with measurements with a static phantom or the planned dose as reference, using 2% and 2 mm gamma criteria. The average pass rate with DMLC tracking was 99.9% (range 98.7-100%, measurement as reference), whereas the pass rate for untracked deliveries decreased distinctly as the average displacement increased, with an average pass rate of 61.3% (range 32.7-99.3%). Dose-volume histograms showed that DMLC tracking maintained the planned dose distributions in the presence of motion whereas traces with >3 mm average displacement caused clear plan degradation for untracked deliveries. The dose to the rectum and bladder had an evident dependence on the motion direction and amplitude for untracked deliveries, and the dose to the rectum was slightly increased for IPL boosted plans compared to conventional plans for anterior motion with large amplitude. In conclusion, optimization using a leaf position constraint had minimal dosimetric effect, DMLC tracking improved the target and normal tissue dose distributions compared to no tracking for target motion >3 mm, with the DMLC tracking distributions showing generally good agreement between the planned and delivered doses.
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Affiliation(s)
- Tobias Pommer
- Radiation Medicine Research Center, Department of Radiation Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
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Chan MKH, Kwong DLW, Ng SCY, Tam EKW, Tong ASM. Investigation of four-dimensional (4D) Monte Carlo dose calculation in real-time tumor tracking stereotatic body radiotherapy for lung cancers. Med Phys 2012; 39:5479-87. [DOI: 10.1118/1.4739249] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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