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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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Paulson ES, Ahunbay E, Chen X, Mickevicius NJ, Chen GP, Schultz C, Erickson B, Straza M, Hall WA, Li XA. 4D-MRI driven MR-guided online adaptive radiotherapy for abdominal stereotactic body radiation therapy on a high field MR-Linac: Implementation and initial clinical experience. Clin Transl Radiat Oncol 2020; 23:72-79. [PMID: 32490218 PMCID: PMC7256110 DOI: 10.1016/j.ctro.2020.05.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/30/2020] [Accepted: 05/03/2020] [Indexed: 12/21/2022] Open
Abstract
This is the first clinical use of 4D-MRI in an online radiation therapy workflow. Eleven patients received SBRT on an Elekta MR-Linac using ATP and ATS workflows. A parallel contour editing approach was successfully utilized in the ATS workflow.
Background and purpose In this report, we describe our implementation and initial clinical experience using 4D-MRI driven MR-guided online adaptive radiotherapy (MRgOART) for abdominal stereotactic body radiotherapy (SBRT) on the Elekta Unity MR-Linac. Materials and methods Eleven patients with abdominal malignancies were treated with free-breathing SBRT in three to five fractions on a 1.5 T MR-Linac. Online adaptive plans were generated using Adapt-To-Position (ATP) or Adapt-To-Shape (ATS) workflows based on motion averaged or mid-position images derived from a pre-beam 4D-MRI. A high performance server positioned on the local MR-Linac machine network was utilized for 4D-MR image reconstruction. A parallel contour editing approach was employed in the ATS workflow. Intravoxel incoherent motion (IVIM) and T2 mapping sequences were acquired during adaptive planning in both ATP and ATS workflows for treatment response monitoring. Adaptive plans were delivered under real-time cine image motion monitoring. Results The shortest 4D-MRI time-to-image was the motion averaged image, followed by mid position and respiratory binned images. In this cohert of patients, 50% of treatments utilized the ATS workflow; the remaining treatments utilized the ATP workflow. Mid-position images were utilized as daily planning images for two of the eleven patients. The mean daily adaptive plan secondary dose calculation and ArcCheck 3D Gamma passing rates were 97.5% (92.1–100.0%) and 99.3% (96.2–100.0%), respectively. The median overall treatment times for abdominal SBRT was 46 and 62 min for ATP and ATS workflows, respectively. Conclusion We have successfully implemented and utilized a 4D-MRI driven MRgOART process with ATP and ATS workflows for free-breathing abdominal SBRT on a 1.5 T Elekta Unity MR-Linac.
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Affiliation(s)
- Eric S Paulson
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States.,Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ergun Ahunbay
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Xinfeng Chen
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Nikolai J Mickevicius
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Guang-Pei Chen
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Christopher Schultz
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Beth Erickson
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michael Straza
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - William A Hall
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - X Allen Li
- Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI, United States
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Mickevicius NJ, Chen X, Boyd Z, Lee HJ, Ibbott GS, Paulson ES. Simultaneous motion monitoring and truth-in-delivery analysis imaging framework for MR-guided radiotherapy. ACTA ACUST UNITED AC 2018; 63:235014. [DOI: 10.1088/1361-6560/aaec91] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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Prins FM, Stemkens B, Kerkmeijer LGW, Barendrecht MM, de Boer HJ, Vonken EJPA, Lagendijk JJW, Tijssen RHN. Intrafraction Motion Management of Renal Cell Carcinoma With Magnetic Resonance Imaging-Guided Stereotactic Body Radiation Therapy. Pract Radiat Oncol 2018; 9:e55-e61. [PMID: 30261329 DOI: 10.1016/j.prro.2018.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 08/26/2018] [Accepted: 09/17/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE One of the major challenges in stereotactic body radiation therapy (SBRT) of renal cell carcinoma is internal motion during treatment. Previous literature has aimed to mitigate the effects of motion by expanding the treatment margins or respiratory tracking. Online magnetic resonance imaging (MRI)-guided radiation therapy has the potential to further improve the treatment of renal cell carcinoma by direct visualization of the tumor during treatment. The efficacy of 2 motion management techniques were assessed: tumor trailing and respiratory tracking. The simulation of a single-fraction, MRI-based SBRT was performed to quantify intrafraction motion and assess the efficacy of the different motion management strategies. METHODS AND MATERIALS Fifteen patients were included in the study. At the beginning and end of the scanning protocol, 2 cine-MRI scans were acquired to assess cyclic respiratory motion. In addition, 3-dimensional spoiled gradient echo scans were acquired at 4 different time points to assess the slow drifts over 25 minutes. The systematic and random errors owing to intrafraction drift were calculated, as well as the random error induced by respiratory motion. The motion margins were calculated for tumor trailing and respiratory tracking and compared with the margin when no motion compensation would be performed to assess the relative efficacy of each technique. RESULTS The largest respiratory tumor motion was observed along the caudo-cranial direction with a median 95% maximum amplitude of approximately 12 mm. ΣDRIFT, σDRIFT, and σRESP were determined to be 1.0 mm 1.8 mm, and 3.8 mm, respectively. Without mechanical immobilization, intrafraction drift accounted for 75% of the total intrafraction motion margin for online midposition-based SBRT treatments. CONCLUSIONS The contribution of intrafraction drift to the total internal motion margin is much larger than periodic respiratory motion. This makes tumor trailing a viable option to consider on the MRI linac because it allows for 3-dimensional MRI acquisitions during beam delivery, which simplifies the introduction of new techniques, such as dose accumulation and online intrafraction replanning.
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Affiliation(s)
- Fieke M Prins
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Bjorn Stemkens
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Linda G W Kerkmeijer
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | | | - Hans J de Boer
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Evert-Jan P A Vonken
- Department of Radiology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Jan J W Lagendijk
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Rob H N Tijssen
- Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, the Netherlands
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Fast M, van de Schoot A, van de Lindt T, Carbaat C, van der Heide U, Sonke JJ. Tumor Trailing for Liver SBRT on the MR-Linac. Int J Radiat Oncol Biol Phys 2018; 103:468-478. [PMID: 30243573 DOI: 10.1016/j.ijrobp.2018.09.011] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 08/09/2018] [Accepted: 09/10/2018] [Indexed: 12/21/2022]
Abstract
PURPOSE Tumor trailing is a treatment delivery technique that continuously adjusts the beam aperture according to the last available time-averaged position of the target. This study investigates whether tumor trailing on a magnetic resonance (MR) linear accelerator (linac) can improve target coverage in liver stereotactic body radiation therapy (SBRT) in the case of baseline motion. METHODS AND MATERIALS For 17 patients with oligometastatic liver disease, midposition SBRT treatment plans (3 × 20 Gy, 11-beam intensity modulated radiotherapy) were created for the Elekta Unity MR-Linac. Treatment was simulated using an in-house-developed delivery emulator. Respiratory motion was modelled as the superposition of periodic motion (patient-specific amplitude, 4-second period) and the following baseline motion scenarios: a continuous linear drift (0.5 mm/min), (2) a single shift halfway through treatment (10 mm), (3) a periodic drift (amplitude: 5 mm, period: 5 minutes), or (4) MR imaging-measured baseline drifts. Delivered dose was calculated under full consideration of the patient and machine motion interplay. In addition, trailing was experimentally validated on the MR-Linac using a programmable motion phantom. RESULTS The average simulated delivery and beam-on times were 15.9 and 8.7 minutes, respectively. An imaging frequency of ≥1 Hz was deemed necessary for trailing. Trailing increased the median gross tumor volume D98% dose by 1.9 Gy (linear drift), 1.2 Gy (single shift), 0.7 Gy (periodic drift), and 0.5 to 1.5 Gy (measured drifts) per fraction, compared with a conventional delivery. In the phantom experiments, the 3%/2 mm local gamma pass rate nearly doubled to 98% when using trailing. CONCLUSION Tumor trailing on the MR-Linac restores target dose in liver SBRT in the case of baseline motion for the presented patient cohort.
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Affiliation(s)
- Martin Fast
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Agustinus van de Schoot
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Tessa van de Lindt
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Casper Carbaat
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Uulke van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Jan-Jakob Sonke
- Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, the Netherlands.
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Mickevicius NJ, Paulson ES. Simultaneous orthogonal plane cine imaging with balanced steady-state free-precession contrast using k-t GRAPPA. ACTA ACUST UNITED AC 2018; 63:15NT02. [DOI: 10.1088/1361-6560/aad008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Heethuis SE, Borggreve AS, Goense L, van Rossum PSN, Mook S, van Hillegersberg R, Ruurda JP, Meijer GJ, Lagendijk JJW, van Lier ALHMW. Quantification of variations in intra-fraction motion of esophageal tumors over the course of neoadjuvant chemoradiotherapy based on cine-MRI. ACTA ACUST UNITED AC 2018; 63:145019. [DOI: 10.1088/1361-6560/aacfb5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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8
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Stemkens B, Glitzner M, Kontaxis C, de Senneville BD, Prins FM, Crijns SPM, Kerkmeijer LGW, Lagendijk JJW, van den Berg CAT, Tijssen RHN. Effect of intra-fraction motion on the accumulated dose for free-breathing MR-guided stereotactic body radiation therapy of renal-cell carcinoma. ACTA ACUST UNITED AC 2017; 62:7407-7424. [DOI: 10.1088/1361-6560/aa83f7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Kubiak T. Particle therapy of moving targets-the strategies for tumour motion monitoring and moving targets irradiation. Br J Radiol 2016; 89:20150275. [PMID: 27376637 DOI: 10.1259/bjr.20150275] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Particle therapy of moving targets is still a great challenge. The motion of organs situated in the thorax and abdomen strongly affects the precision of proton and carbon ion radiotherapy. The motion is responsible for not only the dislocation of the tumour but also the alterations in the internal density along the beam path, which influence the range of particle beams. Furthermore, in case of pencil beam scanning, there is an interference between the target movement and dynamic beam delivery. This review presents the strategies for tumour motion monitoring and moving target irradiation in the context of hadron therapy. Methods enabling the direct determination of tumour position (fluoroscopic imaging of implanted radio-opaque fiducial markers, electromagnetic detection of inserted transponders and ultrasonic tumour localization systems) are presented. Attention is also drawn to the techniques which use external surrogate motion for an indirect estimation of target displacement during irradiation. The role of respiratory-correlated CT [four-dimensional CT (4DCT)] in the determination of motion pattern prior to the particle treatment is also considered. An essential part of the article is the review of the main approaches to moving target irradiation in hadron therapy: gating, rescanning (repainting), gated rescanning and tumour tracking. The advantages, drawbacks and development trends of these methods are discussed. The new accelerators, called "cyclinacs", are presented, because their application to particle therapy will allow making a breakthrough in the 4D spot scanning treatment of moving organs.
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Affiliation(s)
- Tomasz Kubiak
- Medical Physics Division, Faculty of Physics, Adam Mickiewicz University, Poznań, Poland
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Takao S, Miyamoto N, Matsuura T, Onimaru R, Katoh N, Inoue T, Sutherland KL, Suzuki R, Shirato H, Shimizu S. Intrafractional Baseline Shift or Drift of Lung Tumor Motion During Gated Radiation Therapy With a Real-Time Tumor-Tracking System. Int J Radiat Oncol Biol Phys 2016; 94:172-180. [DOI: 10.1016/j.ijrobp.2015.09.024] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 09/08/2015] [Indexed: 10/23/2022]
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Shieh CC, Keall PJ, Kuncic Z, Huang CY, Feain I. Markerless tumor tracking using short kilovoltage imaging arcs for lung image-guided radiotherapy. Phys Med Biol 2015; 60:9437-54. [PMID: 26583772 DOI: 10.1088/0031-9155/60/24/9437] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The ability to monitor tumor motion without implanted markers is clinically advantageous for lung image-guided radiotherapy (IGRT). Existing markerless tracking methods often suffer from overlapping structures and low visibility of tumors on kV projection images. We introduce the short arc tumor tracking (SATT) method to overcome these issues. The proposed method utilizes multiple kV projection images selected from a nine-degree imaging arc to improve tumor localization, and respiratory-correlated 4D cone-beam CT (CBCT) prior knowledge to minimize the effects of overlapping anatomies. The 3D tumor position is solved as an optimization problem with prior knowledge incorporated via regularization. We retrospectively validated SATT on 11 clinical scans from four patients with central tumors. These patients represent challenging scenarios for markerless tumor tracking due to the inferior adjacent contrast. The 3D trajectories of implanted fiducial markers were used as the ground truth for tracking accuracy evaluation. In all cases, the tumors were successfully tracked at all gantry angles. Compared to standard pre-treatment CBCT guidance alone, trajectory errors were significantly smaller with tracking in all cases, and the improvements were the most prominent in the superior-inferior direction. The mean 3D tracking error ranged from 2.2-9.9 mm, which was 0.4-2.6 mm smaller compared to pre-treatment CBCT. In conclusion, we were able to directly track tumors with inferior visibility on kV projection images using SATT. Tumor localization accuracies are significantly better with tracking compared to the current standard of care of lung IGRT. Future work involves the prospective evaluation and clinical implementation of SATT.
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Affiliation(s)
- Chun-Chien Shieh
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, NSW 2006, Australia. Institute of Medical Physics, School of Physics, The University of Sydney, NSW 2006, Australia
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Gou S, Wu J, Liu F, Lee P, Rapacchi S, Hu P, Sheng K. Feasibility of automated pancreas segmentation based on dynamic MRI. Br J Radiol 2014; 87:20140248. [PMID: 25270713 DOI: 10.1259/bjr.20140248] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE MRI-guided radiotherapy is particularly attractive for abdominal targets with low CT contrast. To fully utilize this modality for pancreas tracking, automated segmentation tools are needed. A hybrid gradient, region growth and shape constraint (hGReS) method to segment two-dimensional (2D) upper abdominal dynamic MRI (dMRI) is developed for this purpose. METHODS 2D coronal dynamic MR images of two healthy volunteers were acquired with a frame rate of 5 frames per second. The regions of interest (ROIs) included the liver, pancreas and stomach. The first frame was used as the source where the centres of the ROIs were manually annotated. These centre locations were propagated to the next dMRI frame. Four-neighborhood region transfer growth was performed from these initial seeds before refinement using shape constraints. RESULTS from hGReS and two other automated segmentation methods using integrated edge detection and region growth (IER) and level set, respectively, were compared with manual contours using Dice's index (DI). RESULTS For the first patient, the hGReS resulted in the organ segmentation accuracy as a measure by the DI (0.77) for the pancreas, superior to the level set method (0.72) and IER (0.71). The hGReS was shown to be reproducible on the second subject, achieving a DI of 0.82, 0.92 and 0.93 for the pancreas, stomach and liver, respectively. Motion trajectories derived from the hGReS were highly correlated to respiratory motion. CONCLUSION We have shown the feasibility of automated segmentation of the pancreas anatomy on dMRI. ADVANCES IN KNOWLEDGE Using the hybrid method improves segmentation robustness of low-contrast images.
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Affiliation(s)
- S Gou
- 1 Key Laboratory of Intelligent Perception and Image Understanding of Ministry of Education of China, the School of Electronic Engineering, Xidian University, Xi'an, China
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Kupelian P, Sonke JJ. Magnetic Resonance–Guided Adaptive Radiotherapy: A Solution to the Future. Semin Radiat Oncol 2014; 24:227-32. [DOI: 10.1016/j.semradonc.2014.02.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Pepin EW, Wu H, Shirato H. Use of dMLC for implementation of dynamic respiratory-gated radiation therapy. Med Phys 2014; 40:101708. [PMID: 24089898 DOI: 10.1118/1.4820534] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To simulate and evaluate the use of dynamic multileaf collimators (dMLC) in respiratory gating to compensate for baseline drift. METHODS Tumor motion tracking data from 30 lung tumors over 322 treatment fractions was analyzed with the finite state model. A dynamic respiratory gating window was established in real-time by determining the average positions during the previous two end-of-expiration breathing phases and centering the dMLC aperture on a weighted average of these positions. A simulated dMLC with physical motion constraints was used in dynamic gating treatment simulations. Fluence maps were created to provide a statistical description of radiation delivery for each fraction. Duty cycle was also calculated for each fraction. RESULTS The average duty cycle was 2.3% greater under dynamic gating conditions. Dynamic gating also showed higher fluences and less tumor obstruction. Additionally, dynamic gating required fewer beam toggles and each delivery period was longer on average than with static gating. CONCLUSIONS The use of dynamic gating showed better performance than static gating and the physical constraints of a dMLC were shown to not be an impediment to dynamic gating.
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Affiliation(s)
- Eric W Pepin
- Purdue School of Engineering Technology, IUPUI, Indianapolis, Indiana 46202
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McNamara JE, Regmi R, Michael Lovelock D, Yorke ED, Goodman KA, Rimner A, Mostafavi H, Mageras GS. Toward correcting drift in target position during radiotherapy via computer-controlled couch adjustments on a programmable Linac. Med Phys 2013; 40:051719. [PMID: 23635267 DOI: 10.1118/1.4802736] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Real-time tracking of respiratory target motion during radiation therapy is technically challenging, owing to rapid and possibly irregular breathing variations. The authors report on a method to predict and correct respiration-averaged drift in target position by means of couch adjustments on an accelerator equipped with such capability. METHODS Dose delivery is broken up into a sequence of 10 s field segments, each followed by a couch adjustment based on analysis of breathing motion from an external monitor as a surrogate of internal target motion. Signal averaging over three respiratory cycles yields a baseline representing target drift. A Kalman filter predicts the baseline position 5 s in advance, for determination of the couch correction. The method's feasibility is tested with a motion phantom programmed according to previously recorded patient signals. Computed couch corrections are preprogrammed into a research mode of an accelerator capable of computer-controlled couch translations synchronized with the motion phantom. The method's performance is evaluated with five cases recorded during hypofractionated treatment and five from respiration-correlated CT simulation, using a root-mean-squared deviation (RMSD) of the baseline from the treatment planned position. RESULTS RMSD is reduced in all 10 cases, from a mean of 4.9 mm (range 2.7-9.4 mm) before correction to 1.7 mm (range 0.7-2.3 mm) after correction. Treatment time is increased ∼5% relative to that for no corrections. CONCLUSIONS This work illustrates the potential for reduction in baseline respiratory drift with periodic adjustments in couch position during treatment. Future treatment machine capabilities will enable the use of "on-the-fly" couch adjustments during treatment.
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Affiliation(s)
- Joseph E McNamara
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10065, USA
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Haas OCL, Skworcow P, Paluszczyszyn D, Sahih A, Ruta M, Mills JA. Couch-based motion compensation: modelling, simulation and real-time experiments. Phys Med Biol 2012; 57:5787-807. [DOI: 10.1088/0031-9155/57/18/5787] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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17
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Vergalasova I, Maurer J, Yin FF. Potential underestimation of the internal target volume (ITV) from free-breathing CBCT. Med Phys 2011; 38:4689-99. [PMID: 21928643 DOI: 10.1118/1.3613153] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Localization prior to delivery of SBRT to free-breathing patients is performed by aligning the planning internal target volume (ITV) from 4DCT with an on-board free-breathing cone-beam CT (FB-CBCT) image. The FB-CBCT image is assumed to also generate an ITV that captures the full range of motion, due to the acquisition spanning multiple respiratory cycles. However, the ITV could potentially be underestimated when the ratio of time spent in inspiration versus time spent in expiration (I/E ratio) deviates from unity. Therefore, the aim of this study was to investigate the effect of variable I/E ratios on the FB ITV generated from a FB-CBCT scan. METHODS This study employed both phantom and patient imaging data. For the phantom study, five periodic respiratory cycles were simulated with different I/E ratios. Six patient respiratory cycles with variable I/E ratios were also selected. All profiles were then programmed into a motion phantom for imaging and modified to exhibit three peak-to-peak motion amplitudes (0.5, 1.0, and 2.0 cm). Each profile was imaged using two spherical targets with 1.0 and 3.0 cm diameters. 2D projections were acquired with full gantry rotation of a kiloVoltage (kV) imager mounted onto the gantry of a modem linear accelerator. CBCT images were reconstructed from 2D projections using a standard filtered back-projection reconstruction algorithm. Quantitative analyses for the phantom study included computing the change in contrast along the direction of target motion as well as determining the area (which is proportional to the target volume) inside of the contour extracted using a Canny edge detector. For the patient study, projection data that were previously acquired under an investigational 4D CBCT slow-gantry imaging protocol were used to generate both FB-CBCT and 4D CBCT images. Volumes were then manually contoured from both datasets (using the same window and level) for quantitative comparison. RESULTS The phantom study indicated a reduction in contrast at the inferior edge of the ITV (corresponding to inspiration) as the ratio decreased, for both simulated and patient respiratory cycles. For the simulated phantom respiratory cycles, the contrast reduction of the smallest I/E ratio was 27.6% for the largest target with the smallest amplitude and 89.7% for the smallest target with the largest amplitude. For patient respiratory cycles, these numbers were 22.3% and 94.0%, respectively. The extracted area from inside of the target contours showed a decreasing trend as the I/E ratio decreased. In the patient study, the FB-CBCT ITVs of both lung tumors studied were underestimated when compared with their corresponding 4D CBCT ITV. The underestimations found were 40.1% for the smaller tumor and 24.2% for the larger tumor. CONCLUSIONS The ITV may be underestimated in a FB-CBCT image when a patient's respiratory pattern is characterized by a disparate length of time spent in inspiration versus expiration. Missing the full target motion information during on-board verification imaging may result in localization errors.
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Affiliation(s)
- Irina Vergalasova
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710, USA.
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McQuaid D, Bortfeld T. 4D planning over the full course of fractionation: assessment of the benefit of tumor trailing. Phys Med Biol 2011; 56:6935-49. [PMID: 22008696 DOI: 10.1088/0031-9155/56/21/011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Yoon JW, Sawant A, Suh Y, Cho BC, Suh TS, Keall P. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking. Med Phys 2011; 38:3924-31. [PMID: 21858989 DOI: 10.1118/1.3590384] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described. METHODS The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a tgamma-test with a 3%/3 mm criterion. RESULTS The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%-100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7-1.1 mm for real-time tracking, and 3.7-7.2 mm for no compensation. The percentage of dosimetric points failing the gamma-test ranged from 4 to 30% for moving average tracking, 0%-23% for real-time tracking, and 10%-47% for no compensation. CONCLUSIONS The delivery efficiency of moving average tracking was up to four times higher than that of real-time tracking and approached the efficiency of no compensation for all cases. The geometric accuracy and dosimetric accuracy of the moving average algorithm was between real-time tracking and no compensation, approximately half the percentage of dosimetric points failing the gamma-test compared with no compensation.
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Affiliation(s)
- Jai-Woong Yoon
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Spadea MF, Baroni G, Gierga DP, Turcotte JC, Chen GTY, Sharp GC. Evaluation and commissioning of a surface based system for respiratory sensing in 4D CT. J Appl Clin Med Phys 2010; 12:3288. [PMID: 21330975 PMCID: PMC5718580 DOI: 10.1120/jacmp.v12i1.3288] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2010] [Revised: 09/08/2010] [Accepted: 08/19/2010] [Indexed: 12/25/2022] Open
Abstract
The purpose of this study is to assess the temporal and reconstruction accuracy of a surface imaging system, the GateCT under ideal conditions, and compare the device with a commonly used respiratory surrogate: the Varian RPM. A clinical CT scanner, run in cine mode, was used with two optical devices, GateCT and RPM, to detect respiratory motion. A radiation detector, GM-10, triggers the X-ray on/off to GateCT system, while the RPM is directly synchronized with the CT scanner through an electronic connection. Two phantoms were imaged: the first phantom translated on a rigid plate along the anterior-posterior (AP) direction, and was used to assess the temporal synchronization of each optical system with the CT scanner. The second phantom, consisting of five spheres translating 3 cm peak-to-peak in the superior-inferior direction, was used to assess the quality of rebinned images created by GateCT and RPM. Calibration assessment showed a nearly perfect synchronization with the scanner for both the RPM and GateCT systems, thus demonstrating the good performance of the radiation detector. Results for the volume rebinning test showed discrepancies in volumes for the 3D reconstruction (compared to ground truth) of up to 36% for GateCT and up to 40% for RPM. No statistical difference was proven between the two systems in volume sorting. Errors are mainly due to phase detection inaccuracies and to the large motion of the phantom. This feasibility study assessed the consistency of two optical systems in synchronizing the respiratory signal with the image acquisition. A new patient protocol based on both RPM and GateCT will be soon started.
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Affiliation(s)
- Maria Francesca Spadea
- Department of Experimental and Clinical Medicine, Magna Graecia University viale Europa, Catanzaro, Italy.
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Hugo GD, Liang J, Yan D. Marker-free lung tumor trajectory estimation from a cone beam CT sinogram. Phys Med Biol 2010; 55:2637-50. [PMID: 20393238 DOI: 10.1088/0031-9155/55/9/014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
An algorithm was developed to estimate the 3D lung tumor position using the projection data forming a cone beam CT sinogram and a template registration method. A pre-existing respiration-correlated CT image was used to generate templates of the target, which were then registered to the individual cone beam CT projections, and estimates of the target position were made for each projection. The registration search region was constrained based on knowledge of the mean tumor position during the cone beam CT scan acquisition. Several template registration algorithms were compared, including correlation coefficient and robust methods such as block correlation, robust correlation coefficient and robust gradient correlation. Robust registration metrics were found to be less sensitive to occlusions such as overlying tissue and the treatment couch. The mean accuracy of the position estimation was 1.4 mm in phantom with a robust registration algorithm. In two research subjects with peripheral tumors, the mean position and mean target excursion were estimated to within 2.0 mm compared to the results obtained with a '4D' registration of 4D image volumes.
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Affiliation(s)
- Geoffrey D Hugo
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, USA.
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Vrančić C, Trofimov A, Chan TCY, Sharp GC, Bortfeld T. Experimental evaluation of a robust optimization method for IMRT of moving targets. Phys Med Biol 2009; 54:2901-14. [DOI: 10.1088/0031-9155/54/9/021] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Dieterich S, Cleary K, D’Souza W, Murphy M, Wong KH, Keall P. Locating and targeting moving tumors with radiation beams. Med Phys 2008; 35:5684-94. [DOI: 10.1118/1.3020593] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Sawant A, Venkat R, Srivastava V, Carlson D, Povzner S, Cattell H, Keall P. Management of three-dimensional intrafraction motion through real-time DMLC tracking. Med Phys 2008; 35:2050-61. [PMID: 18561681 PMCID: PMC2809733 DOI: 10.1118/1.2905355] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 02/18/2008] [Accepted: 03/15/2008] [Indexed: 12/25/2022] Open
Abstract
Tumor tracking using a dynamic multileaf collimator (DMLC) represents a promising approach for intrafraction motion management in thoracic and abdominal cancer radiotherapy. In this work, we develop, empirically demonstrate, and characterize a novel 3D tracking algorithm for real-time, conformal, intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)-based radiation delivery to targets moving in three dimensions. The algorithm obtains real-time information of target location from an independent position monitoring system and dynamically calculates MLC leaf positions to account for changes in target position. Initial studies were performed to evaluate the geometric accuracy of DMLC tracking of 3D target motion. In addition, dosimetric studies were performed on a clinical linac to evaluate the impact of real-time DMLC tracking for conformal, step-and-shoot (S-IMRT), dynamic (D-IMRT), and VMAT deliveries to a moving target. The efficiency of conformal and IMRT delivery in the presence of tracking was determined. Results show that submillimeter geometric accuracy in all three dimensions is achievable with DMLC tracking. Significant dosimetric improvements were observed in the presence of tracking for conformal and IMRT deliveries to moving targets. A gamma index evaluation with a 3%-3 mm criterion showed that deliveries without DMLC tracking exhibit between 1.7 (S-IMRT) and 4.8 (D-IMRT) times more dose points that fail the evaluation compared to corresponding deliveries with tracking. The efficiency of IMRT delivery, as measured in the lab, was observed to be significantly lower in case of tracking target motion perpendicular to MLC leaf travel compared to motion parallel to leaf travel. Nevertheless, these early results indicate that accurate, real-time DMLC tracking of 3D tumor motion is feasible and can potentially result in significant geometric and dosimetric advantages leading to more effective management of intrafraction motion.
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Affiliation(s)
- Amit Sawant
- Department of Radiation Oncology, Stanford University, Stanford, California 94305, USA.
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