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Piotrowski T, Ryczkowski A, Kalendralis P, Adamczewski M, Sadowski P, Bajon B, Kruszyna-Mochalska M, Jodda A. Forecasting model for qualitative prediction of the results of patient-specific quality assurance based on planning and complexity metrics and their interrelations. Pilot study. Rep Pract Oncol Radiother 2024; 29:318-328. [PMID: 39144260 PMCID: PMC11321782 DOI: 10.5603/rpor.101093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/31/2024] [Indexed: 08/16/2024] Open
Abstract
Background The purpose was to analyse the interrelations between planning and complexity metrics and gamma passing rates (GPRs) obtained from VMAT treatments and build the forecasting models for qualitative prediction (QD) of GPRs results. Materials and method 802 treatment arcs from the plans prepared for the head and neck, thorax, abdomen, and pelvic cancers were analysed. The plans were verified by portal dosimetry and analysed twice using the gamma method with 3%|2mm and 2%|2mm acceptance criteria. The tolerance limit of GPR was 95%. Red, yellow, and green QDs were established for GPR examination. The interrelations were examined, as well as the analysis of effective differentiation of QD. Three models for QD forecasting based on discriminant analysis (DA), random decision forest (RDF) methods, and the hybrid model (HM) were built and evaluated. Results Most of the interrelations were small or moderate. The exception is correlations of the join function with the average number of monitor units per control point (R = 0.893) and the beam aperture with planning target volume (R = 0.897). While many metrics allow for the effective separation of the QDs from each other, the study shows that predicting the values of the QD is possible only through multi-component forecasting models, of which the HM is the most accurate (0.894). Conclusion Of the three models explored in this study, the HM, which uses DA methods to predict red QD and RDF methods to predict green and yellow QDs, is the most promising one.
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Affiliation(s)
- Tomasz Piotrowski
- Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
- Department of Biomedical Physics, Adam Mickiewicz University, Poznan, Poland
| | - Adam Ryczkowski
- Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
| | - Petros Kalendralis
- Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Marcin Adamczewski
- Department of Biomedical Physics, Adam Mickiewicz University, Poznan, Poland
| | - Piotr Sadowski
- Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland
| | - Barbara Bajon
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
| | - Marta Kruszyna-Mochalska
- Department of Electroradiology, Poznan University of Medical Sciences, Poznan, Poland
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
| | - Agata Jodda
- Department of Medical Physics, Greater Poland Cancer Centre, Poznan, Poland
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Lambri N, Dei D, Goretti G, Crespi L, Brioso RC, Pelizzoli M, Parabicoli S, Bresolin A, Gallo P, La Fauci F, Lobefalo F, Paganini L, Reggiori G, Loiacono D, Franzese C, Tomatis S, Scorsetti M, Mancosu P. Machine learning and lean six sigma for targeted patient-specific quality assurance of volumetric modulated arc therapy plans. Phys Imaging Radiat Oncol 2024; 31:100617. [PMID: 39224688 PMCID: PMC11367262 DOI: 10.1016/j.phro.2024.100617] [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: 04/30/2024] [Revised: 07/25/2024] [Accepted: 07/26/2024] [Indexed: 09/04/2024] Open
Abstract
Background and purpose Radiotherapy plans with excessive complexity exhibit higher uncertainties and worse patient-specific quality assurance (PSQA) results, while the workload of measurement-based PSQA can impact the efficiency of the radiotherapy workflow. Machine Learning (ML) and Lean Six Sigma, a process optimization method, were implemented to adopt a targeted PSQA approach, aiming to reduce workload, risk of failures, and monitor complexity. Materials and methods Lean Six Sigma was applied using DMAIC (define, measure, analyze, improve, and control) steps. Ten complexity metrics were computed for 69,811 volumetric modulated arc therapy (VMAT) arcs from 28,612 plans delivered in our Institute (2013-2021). Outlier complexities were defined as >95th-percentile of the historical distributions, stratified by treatment. An ML model was trained to predict the gamma passing rate (GPR-3 %/1mm) of an arc given its complexity. A decision support system was developed to monitor the complexity and expected GPR. Plans at risk of PSQA failure, either extremely complex or with average GPR <90 %, were identified. The tool's impact was assessed after nine months of clinical use. Results Among 1722 VMAT plans monitored prospectively, 29 (1.7 %) were found at risk of failure. Planners reacted by performing PSQA measurement and re-optimizing the plan. Occurrences of outlier complexities remained stable within 5 %. The expected GPR increased from a median of 97.4 % to 98.2 % (Mann-Whitney p < 0.05) due to plan re-optimization. Conclusions ML and Lean Six Sigma have been implemented in clinical practice enabling a targeted measurement-based PSQA approach for plans at risk of failure to improve overall quality and patient safety.
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Affiliation(s)
- Nicola Lambri
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
- Department of Biomedical Sciences, Humanitas University, via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy
| | - Damiano Dei
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
- Department of Biomedical Sciences, Humanitas University, via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy
| | - Giulia Goretti
- IRCCS Humanitas Research Hospital, Quality Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Leonardo Crespi
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
- Health Data Science Centre, Human Technopole, 20157 Milan, Italy
| | - Ricardo Coimbra Brioso
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
| | - Marco Pelizzoli
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
- Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, Milan, Italy
| | - Sara Parabicoli
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
- Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, Milan, Italy
| | - Andrea Bresolin
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Pasqualina Gallo
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Francesco La Fauci
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Francesca Lobefalo
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Lucia Paganini
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Giacomo Reggiori
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Daniele Loiacono
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, 20133 Milan, Italy
| | - Ciro Franzese
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
- Department of Biomedical Sciences, Humanitas University, via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy
| | - Stefano Tomatis
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
| | - Marta Scorsetti
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
- Department of Biomedical Sciences, Humanitas University, via Rita Levi Montalcini 4, 20072 Pieve Emanuele, Milan, Italy
| | - Pietro Mancosu
- IRCCS Humanitas Research Hospital, Radiotherapy and Radiosurgery Department, via Manzoni 56, 20089 Rozzano, Milan, Italy
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Feng Z, Sun E, China D, Huang X, Hooshangnejad H, Gonzalez EA, Bell MAL, Ding K. Enhancing Image-Guided Radiation Therapy for Pancreatic Cancer: Utilizing Aligned Peak Response Beamforming in Flexible Array Transducers. Cancers (Basel) 2024; 16:1244. [PMID: 38610923 PMCID: PMC11011135 DOI: 10.3390/cancers16071244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/28/2024] [Accepted: 03/08/2024] [Indexed: 04/14/2024] Open
Abstract
To develop ultrasound-guided radiotherapy, we proposed an assistant structure with embedded markers along with a novel alternative method, the Aligned Peak Response (APR) method, to alter the conventional delay-and-sum (DAS) beamformer for reconstructing ultrasound images obtained from a flexible array. We simulated imaging targets in Field-II using point target phantoms with point targets at different locations. In the experimental phantom ultrasound images, image RF data were acquired with a flexible transducer with in-house assistant structures embedded with needle targets for testing the accuracy of the APR method. The lateral full width at half maximum (FWHM) values of the objective point target (OPT) in ground truth ultrasound images, APR-delayed ultrasound images with a flat shape, and images acquired with curved transducer radii of 500 mm and 700 mm were 3.96 mm, 4.95 mm, 4.96 mm, and 4.95 mm. The corresponding axial FWHM values were 1.52 mm, 4.08 mm, 5.84 mm, and 5.92 mm, respectively. These results demonstrate that the proposed assistant structure and the APR method have the potential to construct accurate delay curves without external shape sensing, thereby enabling a flexible ultrasound array for tracking pancreatic tumor targets in real time for radiotherapy.
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Affiliation(s)
- Ziwei Feng
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (Z.F.); (E.S.); (H.H.)
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; (E.A.G.); (M.A.L.B.)
| | - Edward Sun
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (Z.F.); (E.S.); (H.H.)
- Department of Computer Science, University of California, Los Angeles, CA 90095, USA
| | - Debarghya China
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (D.C.); (X.H.)
| | - Xinyue Huang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (D.C.); (X.H.)
| | - Hamed Hooshangnejad
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (Z.F.); (E.S.); (H.H.)
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (D.C.); (X.H.)
| | - Eduardo A. Gonzalez
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; (E.A.G.); (M.A.L.B.)
| | - Muyinatu A. Lediju Bell
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; (E.A.G.); (M.A.L.B.)
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (D.C.); (X.H.)
- Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Kai Ding
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; (Z.F.); (E.S.); (H.H.)
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Hui CB, Pourmoghaddas A, Mutaf YD. The effects of flattening filter-free beams and aperture shape controller on the complexity of conventional large-field treatment plans. J Appl Clin Med Phys 2023; 24:e14108. [PMID: 37528683 PMCID: PMC10647973 DOI: 10.1002/acm2.14108] [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: 04/24/2023] [Revised: 06/23/2023] [Accepted: 07/14/2023] [Indexed: 08/03/2023] Open
Abstract
PURPOSE The purpose of this study was to investigate the impact of using flattening filter-free (FFF) beams and the aperture shape controller (ASC) on the complexity of conventional large-field treatment plans. METHODS AND MATERIALS A total of 24 head and neck (H&N) and 24 prostate with pelvic nodes treatment plans were used in this study. Each plan was reoptimized using the original clinical objectives with both flattened and FFF beams, as well as six different ASC settings. The dosimetric qualities of each plan cohort were evaluated using commonly used dose-volume histogram values, and plan complexities were assessed through metrics including monitor unit (MU)/Dose, change in gantry speed, multileaf collimator (MLC) speed, the edge area ratio metric (EM), and the equivalent square length. RESULTS No significant differences in dosimetric qualities were found between plans with flattened and FFF beams. The ASC settings did not have significant effects on dosimetric qualities in the H&N plan cohort, but the "very high" ASC setting resulted in poorer dosimetric results for the prostate plans. Plans with FFF beams had significantly higher MU/Dose compared to plans with flattened beams. The use of flattening filter (FF) had significant effects on the change in gantry speed, with flattened beams producing plans that required higher change in gantry speed. However, the FF did not have significant effects on MLC speed, EM, or equivalent square length. In contrast, ASC settings had significant effects on these three metrics; increasing the ASC level resulted in plans with decreasing MLC speed, lower edge area ratio, and higher equivalent square length. CONCLUSION This study demonstrated that using FFF beams with various ASC settings, except for the "very high" level, can produce plans with reduced complexities without compromising dosimetric qualities in conventional large-field treatment plans.
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Affiliation(s)
- Cheukkai B. Hui
- Department of Radiation OncologyKaiser PermanenteDublinCaliforniaUSA
| | | | - Yildirim D. Mutaf
- Department of Radiation OncologyKaiser PermanenteDublinCaliforniaUSA
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Wang Y, Shen J, Gu P, Wang Z. Recent advances progress in radiotherapy for breast cancer after breast-conserving surgery: a review. Front Oncol 2023; 13:1195266. [PMID: 37671064 PMCID: PMC10475720 DOI: 10.3389/fonc.2023.1195266] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/07/2023] [Indexed: 09/07/2023] Open
Abstract
Adjuvant radiotherapy after breast-conserving surgery has become an integral part of the treatment of breast cancer. In recent years, the development of radiotherapy technology has made great progress in this field, including the comparison of the curative effects of various radiotherapy techniques and the performance of the segmentation times. The choice of radiotherapy technology needs to be co-determined by clinical evidence practice and evaluated for each individual patient to achieve precision radiotherapy. This article discusses the treatment effects of different radiotherapy, techniques, the risk of second cancers and short-range radiation therapy techniques after breast-conserving surgery such as hypo fractionated whole breast irradiation and accelerated partial breast irradiation. The choice of radiotherapy regimen needs to be based on the individual condition of the patient, and the general principle is to focus on the target area and reduce the irradiation of the normal tissues and organs. Short-range radiotherapy and hypofractionated are superior to conventional radiotherapy and are expected to become the mainstream treatment after breast-conserving surgery.
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Affiliation(s)
- Yun Wang
- Department of Radiation Oncology, Shidong Hospital, Shidong Hospital Affiliated to University of Shanghai for Science and Technology, Shanghai, China
| | - Jingjing Shen
- Department of Radiation Oncology, Shidong Hospital, Shidong Hospital Affiliated to University of Shanghai for Science and Technology, Shanghai, China
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Peihua Gu
- Department of Radiation Oncology, Shidong Hospital, Shidong Hospital Affiliated to University of Shanghai for Science and Technology, Shanghai, China
| | - Zhongming Wang
- Department of Radiation Oncology, Shidong Hospital, Shidong Hospital Affiliated to University of Shanghai for Science and Technology, Shanghai, China
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
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Huang X, Hooshangnejad H, China D, Feng Z, Lee J, Bell MAL, Ding K. Ultrasound Imaging with Flexible Array Transducer for Pancreatic Cancer Radiation Therapy. Cancers (Basel) 2023; 15:3294. [PMID: 37444403 DOI: 10.3390/cancers15133294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 06/02/2023] [Accepted: 06/19/2023] [Indexed: 07/15/2023] Open
Abstract
Pancreatic cancer with less than 10% 3-year survival rate is one of deadliest cancer types and greatly benefits from enhanced radiotherapy. Organ motion monitoring helps spare the normal tissue from high radiation and, in turn, enables the dose escalation to the target that has been shown to improve the effectiveness of RT by doubling and tripling post-RT survival rate. The flexible array transducer is a novel and promising solution to address the limitation of conventional US probes. We proposed a novel shape estimation for flexible array transducer using two sequential algorithms: (i) an optical tracking-based system that uses the optical markers coordinates attached to the probe at specific positions to estimate the array shape in real-time and (ii) a fully automatic shape optimization algorithm that automatically searches for the optimal array shape that results in the highest quality reconstructed image. We conducted phantom and in vivo experiments to evaluate the estimated array shapes and the accuracy of reconstructed US images. The proposed method reconstructed US images with low full-width-at-half-maximum (FWHM) of the point scatters, correct aspect ratio of the cyst, and high-matching score with the ground truth. Our results demonstrated that the proposed methods reconstruct high-quality ultrasound images with significantly less defocusing and distortion compared with those without any correction. Specifically, the automatic optimization method reduced the array shape estimation error to less than half-wavelength of transmitted wave, resulting in a high-quality reconstructed image.
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Affiliation(s)
- Xinyue Huang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Hamed Hooshangnejad
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21287, USA
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Debarghya China
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Ziwei Feng
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Junghoon Lee
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Muyinatu A Lediju Bell
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Kai Ding
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
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Tefagh M, Zarepisheh M. Built-in wavelet-induced smoothness to reduce plan complexity in intensity modulated radiation therapy (IMRT). Phys Med Biol 2023; 68. [PMID: 36827706 DOI: 10.1088/1361-6560/acbefe] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 02/24/2023] [Indexed: 02/26/2023]
Abstract
Objective.Reducing plan complexity in intensity modulated radiation therapy (IMRT) to ensure dosimetric accuracy and delivery efficiency of the radiation treatment plans. We propose a novel approach by representing the beamlet intensities using an incomplete wavelet basis that explicitly excludes fluctuating intensity maps from the decision space (explicit hard constraint). This technique provides a built-in wavelet-induced smoothness that improves both dosimetric plan quality and delivery efficiency.Approach.The beamlet intensity maps need to be especially smooth in the leaf travel direction (referred to as theX-direction). We treat the intensity map of each beam as a 2D image and represent it using the wavelets corresponding to low-frequency changes in theX-direction (i.e. approximation and horizontal). The absence of wavelets corresponding to high-frequency changes (i.e. vertical and diagonal) induces built-in smoothness. We still utilize a regularization term in the objective function to promote smoothness in theY-direction (perpendicular to theX-direction) and further possible smoothness in theX-direction. This technique has been tested on three patient cases of different disease sites (paraspinal, lung, prostate) and all final evaluations and comparisons have been performed on an FDA-approved commercial treatment planning system (Varian EclipseTM).Main results.Wavelet-induced smoothness reduced monitor units by about 10%, 45%, and 14% for paraspinal, lung, and prostate cases, respectively. It also improved organ at risk sparing, especially on the complex paraspinal case where it resulted in about 7%, 13%, and 14% less mean dose to esophagus, lung, and cord, respectively. Moreover, built-in wavelet-induced smoothness desensitizes the results to changing the weight associated to the regularization term, and thereby mitigates the weight fine-tuning difficulty.Significance.Fluence smoothness is often achieved by smoothing the beamlet intensity maps using a proper regularization term in the objective function aiming at disincentivizing fluctuation in the beamlet intensities (implicit soft constraint). This work reports a novel application of wavelets in imposing an explicit smoothness hard constraint in the search space using an incomplete wavelet basis. This idea has been successfully applied to exclude complex and clinically irrelevant radiation plans from the search space. The code and pertained models along with a sample dataset are released on our LowDimRT GitHub (https://github.com/PortPy-Project/LowDimRT).
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Affiliation(s)
- Mojtaba Tefagh
- Department of Mathematical Sciences, Sharif University of Technology, Tehran, Iran
| | - Masoud Zarepisheh
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
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An effective and optimized patient-specific QA workload reduction for VMAT plans after MLC-modelling optimization. Phys Med 2023; 107:102548. [PMID: 36842260 DOI: 10.1016/j.ejmp.2023.102548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 01/16/2023] [Accepted: 02/13/2023] [Indexed: 02/26/2023] Open
Abstract
INTRODUCTION Many complexity metrics characterize modulated plans. First, this study aimed at identify the optimal complexity metrics to reduce workload associated to patient-specific quality assurance (PSQA) for our equipment and processes. Second, it intended to optimize our MLC modelling to improve measurement and calculation agreement with expectation of further reducing PSQA workload. METHODS Correlation and sensitivity at specificity equals to 1 were evaluated for PSQA results and different complexity metrics. Thresholds to stop PSQA were determined. After validation of the optimal complexity metric and threshold for our equipment and process, the MLC modelling was reviewed with a recently published methodology. This method is based on measurements with a Farmer-type ionization chamber of synchronous and asynchronous sweeping gap plans. Effect on the PSQA results and the identified threshold was investigated. RESULTS In our center, the most appropriate complexity metric for reducing our PSQA workload was the Modulation Complexity Score for VMAT (MCSv). The optimization of the MLC modelling significantly reduced the number of controlled plans, specifically for one of our two Varian Clinac. Any plan with a MCSv >= 0.34 is treated without PSQA. CONCLUSION This study rationalized and reduced our PSQA workload by approximately 30%. It is a continuing work with new TPS, machine or PSQA equipment. It encourages centers to re-evaluate their MLC modelling as well as assess the benefit of complexity metrics to streamline their PSQA workflow. An easier access, at least for reporting, at best for optimizing plans, into the TPS would be beneficial for the community.
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Shen J, Wang Y, Wang L, Gu P, Wang Z. Dosimetric effects of the custom dose iteration times on stereotactic radiotherapy for lung cancer. Radiat Phys Chem Oxf Engl 1993 2023. [DOI: 10.1016/j.radphyschem.2023.110882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
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Prediction and classification of VMAT dosimetric accuracy using plan complexity and log-files analysis. Phys Med 2022; 103:76-88. [DOI: 10.1016/j.ejmp.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/20/2022] [Accepted: 10/07/2022] [Indexed: 11/18/2022] Open
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A measurement validation of improved plan deliverability with monitor unit objective tool for spine stereotactic ablative radiotherapy. Med Dosim 2022; 48:25-30. [PMID: 36280549 DOI: 10.1016/j.meddos.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/25/2022] [Accepted: 09/20/2022] [Indexed: 02/04/2023]
Abstract
Spine stereotactic body radiation therapy (SBRT) uses high dose per fraction for palliative pain control. The treatment plans are often heavily modulated due to close proximity to spinal cord and this can lead to poor plan quality which are susceptible to dose delivery discrepancy. Therefore, we aim to assess the effectiveness of the monitor unit (MU) objective tool in Eclipse treatment planning systems in modulating the plan complexity to improve the plan quality in spine SBRT. Seven retrospective spine SBRT plans are re-optimized using the MU objective tool in Eclipse TPS v13.6 and were compared with the original plans. The dose metrics of the tumor PTV were compared using D1cc. D99%, D95%, D0.03cc, D0.1cc, D0.35cc and D1cc, and that of cord PRV were compared using D0.03cc, D0.1cc, D0.35cc. Four different plan complexities were also calculated for the original and re-optimized plans to quantify the impact of the tool on the modulation. Patient specific quality assurance measurements were performed with Stereophan and SRS MapCheck, and analyzed using the 1%/1-mm and 2%/2-mm criteria with gamma analysis. The dose metrics of the PTV and cord PRV of the re-optimized and original plans are similar and still meet the planning dose constraints. In particular, the PTV dose coverage has a small percentage difference of (0.15 ± 1.33)% and (0.01 ± 1.04)% for D99% and D95%, respectively. The 4 calculated plan complexity metrics consistently show that the re-optimized plans are quantitatively less complex than the original plan. The gamma passing rate of the re-optimized plans improved from (92.2 ± 2.0)% to (94.2 ± 1.6)% with the 1%/1-mm criterion, and (98.7 ± 1.0)% to (99.5 ± 0.3)% with the 2%/2-mm criterion. Overall, the re-optimized plans achieve at least a 10% MU reduction (11.7% to 24.6%). Our study shows that optimization with the MU objective tool can reduce plan complexity and improves dose delivery accuracy, while not compromising the dose distribution.
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Babier A, Mahmood R, Zhang B, Alves VGL, Barragán-Montero AM, Beaudry J, Cardenas CE, Chang Y, Chen Z, Chun J, Diaz K, Eraso HD, Faustmann E, Gaj S, Gay S, Gronberg M, Guo B, He J, Heilemann G, Hira S, Huang Y, Ji F, Jiang D, Giraldo JCJ, Lee H, Lian J, Liu S, Liu KC, Marrugo J, Miki K, Nakamura K, Netherton T, Nguyen D, Nourzadeh H, Osman AFI, Peng Z, Muñoz JDQ, Ramsl C, Rhee DJ, Rodriguez JD, Shan H, Siebers JV, Soomro MH, Sun K, Hoyos AU, Valderrama C, Verbeek R, Wang E, Willems S, Wu Q, Xu X, Yang S, Yuan L, Zhu S, Zimmermann L, Moore KL, Purdie TG, McNiven AL, Chan TCY. OpenKBP-Opt: an international and reproducible evaluation of 76 knowledge-based planning pipelines. Phys Med Biol 2022; 67:10.1088/1361-6560/ac8044. [PMID: 36093921 PMCID: PMC10696540 DOI: 10.1088/1361-6560/ac8044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 07/11/2022] [Indexed: 11/12/2022]
Abstract
Objective.To establish an open framework for developing plan optimization models for knowledge-based planning (KBP).Approach.Our framework includes radiotherapy treatment data (i.e. reference plans) for 100 patients with head-and-neck cancer who were treated with intensity-modulated radiotherapy. That data also includes high-quality dose predictions from 19 KBP models that were developed by different research groups using out-of-sample data during the OpenKBP Grand Challenge. The dose predictions were input to four fluence-based dose mimicking models to form 76 unique KBP pipelines that generated 7600 plans (76 pipelines × 100 patients). The predictions and KBP-generated plans were compared to the reference plans via: the dose score, which is the average mean absolute voxel-by-voxel difference in dose; the deviation in dose-volume histogram (DVH) points; and the frequency of clinical planning criteria satisfaction. We also performed a theoretical investigation to justify our dose mimicking models.Main results.The range in rank order correlation of the dose score between predictions and their KBP pipelines was 0.50-0.62, which indicates that the quality of the predictions was generally positively correlated with the quality of the plans. Additionally, compared to the input predictions, the KBP-generated plans performed significantly better (P< 0.05; one-sided Wilcoxon test) on 18 of 23 DVH points. Similarly, each optimization model generated plans that satisfied a higher percentage of criteria than the reference plans, which satisfied 3.5% more criteria than the set of all dose predictions. Lastly, our theoretical investigation demonstrated that the dose mimicking models generated plans that are also optimal for an inverse planning model.Significance.This was the largest international effort to date for evaluating the combination of KBP prediction and optimization models. We found that the best performing models significantly outperformed the reference dose and dose predictions. In the interest of reproducibility, our data and code is freely available.
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Affiliation(s)
- Aaron Babier
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Vector Institute, Toronto, ON, Canada
| | - Rafid Mahmood
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Binghao Zhang
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
| | - Victor G L Alves
- Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA, United States of America
| | | | - Joel Beaudry
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, United States of America
| | - Carlos E Cardenas
- Department of Radiation Oncology, The University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Yankui Chang
- Department of Engineering and Applied Physics, University of Science and Technology of China, Hefei, People’s Republic of China
| | - Zijie Chen
- Shenying Medical Technology Co., Ltd., Shenzhen, Guangdong, People’s Republic of China
| | - Jaehee Chun
- Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Kelly Diaz
- Department of Physics, National University of Colombia, Medellín, Colombia
| | - Harold David Eraso
- Department of Physics, National University of Colombia, Medellín, Colombia
| | - Erik Faustmann
- Atominstitut, Vienna University of Technology, Vienna, Austria
| | - Sibaji Gaj
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, United States of America
| | - Skylar Gay
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America
| | - Mary Gronberg
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America
| | - Bingqi Guo
- Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH, United States of America
| | - Junjun He
- Department of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Gerd Heilemann
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
| | - Sanchit Hira
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States of America
| | - Yuliang Huang
- Department of Radiation Oncology, Peking University Cancer Hospital and Institute, Beijing, People’s Republic of China
| | - Fuxin Ji
- Department of Electrical Engineering and Automation, Anhui University, Hefei, People’s Republic of China
| | - Dashan Jiang
- Department of Electrical Engineering and Automation, Anhui University, Hefei, People’s Republic of China
| | | | - Hoyeon Lee
- Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, United States of America
| | - Jun Lian
- Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America
| | - Shuolin Liu
- Department of Electrical Engineering and Automation, Anhui University, Hefei, People’s Republic of China
| | - Keng-Chi Liu
- Department of Medical Imaging, Taiwan AI Labs, Taipei, Taiwan
| | - José Marrugo
- Department of Physics, National University of Colombia, Medellín, Colombia
| | - Kentaro Miki
- Department Of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kunio Nakamura
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH, United States of America
| | - Tucker Netherton
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America
| | - Dan Nguyen
- Medical Artificial Intelligence and Automation (MAIA) Laboratory, Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Hamidreza Nourzadeh
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, United States of America
| | | | - Zhao Peng
- Department of Engineering and Applied Physics, University of Science and Technology of China, Hefei, People’s Republic of China
| | | | - Christian Ramsl
- Atominstitut, Vienna University of Technology, Vienna, Austria
| | - Dong Joo Rhee
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America
| | | | - Hongming Shan
- Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, People’s Republic of China
| | - Jeffrey V Siebers
- Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Mumtaz H Soomro
- Department of Radiation Oncology, University of Virginia Health System, Charlottesville, VA, United States of America
| | - Kay Sun
- Studio Vodels, Atlanta, GA, United States of America
| | - Andrés Usuga Hoyos
- Department of Physics, National University of Colombia, Medellín, Colombia
| | - Carlos Valderrama
- Department of Physics, National University of Colombia, Medellín, Colombia
| | - Rob Verbeek
- Department Computer Science, Aalto University, Espoo, Finland
| | - Enpei Wang
- Shenying Medical Technology Co., Ltd., Shenzhen, Guangdong, People’s Republic of China
| | - Siri Willems
- Department of Electrical Engineering, KULeuven, Leuven, Belgium
| | - Qi Wu
- Department of Electrical Engineering and Automation, Anhui University, Hefei, People’s Republic of China
| | - Xuanang Xu
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States of America
| | - Sen Yang
- Tencent AI Lab, Shenzhen, Guangdong, People’s Republic of China
| | - Lulin Yuan
- Department of Radiation Oncology, Virginia Commonwealth University Medical Center, Richmond, VA, United States of America
| | - Simeng Zhu
- Department of Radiation Oncology, Henry Ford Health System, Detroit, MI, United States of America
| | - Lukas Zimmermann
- Faculty of Health, University of Applied Sciences Wiener Neustadt, Wiener Neustadt, Austria
- Competence Center for Preclinical Imaging and Biomedical Engineering, University of Applied Sciences Wiener Neustadt, Wiener Neustadt, Austria
| | - Kevin L Moore
- Department of Radiation Oncology, University of California, San Diego, La Jolla, CA, United States of America
| | - Thomas G Purdie
- Radiation Medicine Program, UHN Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
- Techna Institute for the Advancement of Technology for Health, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Andrea L McNiven
- Radiation Medicine Program, UHN Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Radiation Oncology, University of Toronto, Toronto, ON, Canada
| | - Timothy C Y Chan
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, ON, Canada
- Vector Institute, Toronto, ON, Canada
- Techna Institute for the Advancement of Technology for Health, Toronto, ON, Canada
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Evaluation of an automated template-based treatment planning system for radiotherapy of anal, rectal and prostate cancer. Tech Innov Patient Support Radiat Oncol 2022; 22:30-36. [PMID: 35464888 PMCID: PMC9020095 DOI: 10.1016/j.tipsro.2022.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 03/11/2022] [Accepted: 04/05/2022] [Indexed: 11/21/2022] Open
Abstract
Automated treatment planning system compared to manual planning. Equivalent plan quality between VMAT manually generated- and IMRT automatically generated plans. Evaluation of anal, prostate and rectum treatment plans. Generation of highly consistent IMRT automated plan within 2 to 3.5 min.
Background and purpose The Ethos system has enabled online adaptive radiotherapy (oART) by implementing an automated treatment planning system (aTPS) for both intensity-modulated radiotherapy (IMRT) and volumetric modulated arc radiotherapy (VMAT) plan creation. The purpose of this study is to evaluate the quality of aTPS plans in the pelvic region. Material and Methods Sixty patients with anal (n = 20), rectal (n = 20) or prostate (n = 20) cancer were retrospectively re-planned with the aTPS. Three IMRT (7-, 9- and 12-field) and two VMAT (2 and 3 arc) automatically generated plans (APs) were created per patient. The duration of the automated plan generation was registered. The best IMRT-AP and VMAT-AP for each patient were selected based on target coverage and dose to organs at risk (OARs). The AP quality was analyzed and compared to corresponding clinically accepted and manually generated VMAT plans (MPs) using several clinically relevant dose metrics. Calculation-based pre-treatment plan quality assurance (QA) was performed for all plans. Results The median total duration to generate the five APs with the aTPS was 55 min, 39 min and 35 min for anal, prostate and rectal plans, respectively. The target coverage and the OAR sparing were equivalent for IMRT-APs and VMAT-MPs, while VMAT-Aps. demonstrated lower target dose homogeneity and higher dose to some OARs. Both conformity and homogeneity index were equivalent (rectal) or better (anal and prostate) for IMRT-APs compared to VMAT-MPs. All plans passed the patient-specific QA tolerance limit. Conclusions The aTPS generates plans comparable to MPs within a short time-frame which is highly relevant for oART treatments.
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Key Words
- AP, automatically generated plan
- Automated treatment planning
- CN, conformity number
- CT, computed tomography
- CTV, clinical target volume
- DVH, dose volume histogram
- FFF, flattening filter free
- GTV, gross tumor volume
- HI, homogeneity index
- IMRT, intensity modulated radiotherapy
- Intelligent optimization engine
- KPB, knowledge-based planning
- Linac, Linear accelerators
- MCO, multi-criteria optimization
- MLC, multileaf collimator
- MP, manually-generated plan
- MR, magnetic resonance
- MU, Monitor Unit
- OAR, Organ at risk
- Online adaptive radiotherapy
- PTV, planning target volume
- Pelvic cancer
- Plan quality
- QA, Quality assurance
- SD, standard deviation
- Template-based Ethos TPS
- VMAT, volumetric arc radiotherapy
- aTPS, automated treatment planning system
- oART, online adaptive radiotherapy
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Anchineyan P, Amalraj J, Krishnan BT, Ananthalakshmi MC, Jayaraman P, Krishnasamy R. Assessment of Knowledge-Based Planning Model in Combination with Multi-Criteria Optimization in Head-and-Neck Cancers. J Med Phys 2022; 47:119-125. [PMID: 36212210 PMCID: PMC9543001 DOI: 10.4103/jmp.jmp_84_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/27/2022] [Accepted: 02/05/2022] [Indexed: 11/04/2022] Open
Abstract
Aim The aim of this study was to build knowledge-based planning model (KBPM) for head-and-neck (HN) cancers using volumetric-modulated arc therapy (VMAT), optimized with multi-criteria optimization (MCO), and to evaluate KBPM plan quality with clinical plan (CP) using in-house developed Python script. Materials and Methods Two hundred previously treated simultaneously integrated boost (SIB) HN VMAT plans (RapidArc®) were selected for creating KBPM. These plans were further optimized using MCO to strike right trade-off between target and organs at risk (OARs). The script was written using Python V3.7.1 to automatically extract and analyze treatment plan dosimetric parameters through Eclipse Scripting Application Programming Interface (ESAPI). Analyzed plans that met deliverable quality were modeled using regression-based KBPM framework. The trained model is validated with 35 cohorts of HN SIB patients. Results MCO plans were able to improve the OAR sparing without compromising target coverage compared to user-optimized CPs except for increased heterogeneity. With MCO, spinal cord dose D0.03cc is reduced by 3.2 Gy ± 1.8 Gy, parotid mean dose by 2 Gy ± 1.7 Gy compared to CPs, respectively. MCO-based KBPM plans were comparable to CP with improved sparing for left and right parotids by 11.5% and 7.8%, respectively. Conclusion MCO-based KBPM plans were superior to user plans in terms of OAR sparing and user need to spend more time to meet the model-based plan outcomes. Created KBPM planning is simple and efficient to generate estimate for OAR sparing to guide entry and intermittent planners to improve their clinical planning skills with lesser planning time. Python ESAPI is a powerful tool to extract plan parameters and quickly evaluate either individual or a cohort of plans.
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Affiliation(s)
- Pichandi Anchineyan
- Department of Radiation Oncology, Healthcare Global Enterprises, Bengaluru, Karnataka, India
| | - Jerrin Amalraj
- Department of Radiation Oncology, Healthcare Global Enterprises, Bengaluru, Karnataka, India
| | | | | | - Punitha Jayaraman
- Department of Radiation Oncology, Healthcare Global Enterprises, Bengaluru, Karnataka, India
| | - Ramkumar Krishnasamy
- Department of Radiation Oncology, Healthcare Global Enterprises, Bengaluru, Karnataka, India
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Huang X, Lediju Bell MA, Ding K. Deep Learning for Ultrasound Beamforming in Flexible Array Transducer. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:3178-3189. [PMID: 34101588 PMCID: PMC8609563 DOI: 10.1109/tmi.2021.3087450] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ultrasound imaging has been developed for image-guided radiotherapy for tumor tracking, and the flexible array transducer is a promising tool for this task. It can reduce the user dependence and anatomical changes caused by the traditional ultrasound transducer. However, due to its flexible geometry, the conventional delay-and-sum (DAS) beamformer may apply incorrect time delay to the radio-frequency (RF) data and produce B-mode images with considerable defocusing and distortion. To address this problem, we propose a novel end-to-end deep learning approach that may alternate the conventional DAS beamformer when the transducer geometry is unknown. Different deep neural networks (DNNs) were designed to learn the proper time delays for each channel, and they were expected to reconstruct the undistorted high-quality B-mode images directly from RF channel data. We compared the DNN results to the standard DAS beamformed results using simulation and flexible array transducer scan data. With the proposed DNN approach, the averaged full-width-at-half-maximum (FWHM) of point scatters is 1.80 mm and 1.31 mm lower in simulation and scan results, respectively; the contrast-to-noise ratio (CNR) of the anechoic cyst in simulation and phantom scan is improved by 0.79 dB and 1.69 dB, respectively; and the aspect ratios of all the cysts are closer to 1. The evaluation results show that the proposed approach can effectively reduce the distortion and improve the lateral resolution and contrast of the reconstructed B-mode images.
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Affiliation(s)
- Xinyue Huang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Muyinatu A. Lediju Bell
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD 21218 USA, and also with the Department of Biomedical Engineering and the Department of Computer Science, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Kai Ding
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287 USA
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16
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Babier A, Zhang B, Mahmood R, Moore KL, Purdie TG, McNiven AL, Chan TCY. OpenKBP: The open-access knowledge-based planning grand challenge and dataset. Med Phys 2021; 48:5549-5561. [PMID: 34156719 DOI: 10.1002/mp.14845] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 02/04/2021] [Accepted: 02/18/2021] [Indexed: 01/17/2023] Open
Abstract
PURPOSE To advance fair and consistent comparisons of dose prediction methods for knowledge-based planning (KBP) in radiation therapy research. METHODS We hosted OpenKBP, a 2020 AAPM Grand Challenge, and challenged participants to develop the best method for predicting the dose of contoured computed tomography (CT) images. The models were evaluated according to two separate scores: (a) dose score, which evaluates the full three-dimensional (3D) dose distributions, and (b) dose-volume histogram (DVH) score, which evaluates a set DVH metrics. We used these scores to quantify the quality of the models based on their out-of-sample predictions. To develop and test their models, participants were given the data of 340 patients who were treated for head-and-neck cancer with radiation therapy. The data were partitioned into training ( n = 200 ), validation ( n = 40 ), and testing ( n = 100 ) datasets. All participants performed training and validation with the corresponding datasets during the first (validation) phase of the Challenge. In the second (testing) phase, the participants used their model on the testing data to quantify the out-of-sample performance, which was hidden from participants and used to determine the final competition ranking. Participants also responded to a survey to summarize their models. RESULTS The Challenge attracted 195 participants from 28 countries, and 73 of those participants formed 44 teams in the validation phase, which received a total of 1750 submissions. The testing phase garnered submissions from 28 of those teams, which represents 28 unique prediction methods. On average, over the course of the validation phase, participants improved the dose and DVH scores of their models by a factor of 2.7 and 5.7, respectively. In the testing phase one model achieved the best dose score (2.429) and DVH score (1.478), which were both significantly better than the dose score (2.564) and the DVH score (1.529) that was achieved by the runner-up models. Lastly, many of the top performing teams reported that they used generalizable techniques (e.g., ensembles) to achieve higher performance than their competition. CONCLUSION OpenKBP is the first competition for knowledge-based planning research. The Challenge helped launch the first platform that enables researchers to compare KBP prediction methods fairly and consistently using a large open-source dataset and standardized metrics. OpenKBP has also democratized KBP research by making it accessible to everyone, which should help accelerate the progress of KBP research. The OpenKBP datasets are available publicly to help benchmark future KBP research.
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Affiliation(s)
- Aaron Babier
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON, M5S 3G8, Canada
| | - Binghao Zhang
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON, M5S 3G8, Canada
| | - Rafid Mahmood
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON, M5S 3G8, Canada
| | - Kevin L Moore
- Department of Radiation Oncology, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA, 92104, USA
| | - Thomas G Purdie
- Radiation Medicine Program, UHN Princess Margaret Cancer Centre, 610 University of Avenue, Toronto, ON, M5T 2M9, Canada.,Department of Radiation Oncology, University of Toronto, 148 - 150 College Street, Toronto, ON, M5S 3S2, Canada
| | - Andrea L McNiven
- Radiation Medicine Program, UHN Princess Margaret Cancer Centre, 610 University of Avenue, Toronto, ON, M5T 2M9, Canada.,Department of Radiation Oncology, University of Toronto, 148 - 150 College Street, Toronto, ON, M5S 3S2, Canada
| | - Timothy C Y Chan
- Department of Mechanical and Industrial Engineering, University of Toronto, 5 King's College Road, Toronto, ON, M5S 3G8, Canada.,Techna Institute for the Advancement of Technology for Health, 124 - 100 College Street Toronto, ON, M5G 1P5, Canada
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Evaluation of treatment plan quality for head and neck IMRT: a multicenter study. Med Dosim 2021; 46:310-317. [PMID: 33838998 DOI: 10.1016/j.meddos.2021.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/06/2021] [Accepted: 03/05/2021] [Indexed: 11/23/2022]
Abstract
Intensity-modulated radiotherapy (IMRT) treatment planning for head and neck cancer is challenging and complex due to many organs at risk (OAR) in this region. The experience and skills of planners may result in substantial variability of treatment plan quality. This study assessed the performance of IMRT planning in Malaysia and observed plan quality variation among participating centers. The computed tomography dataset containing contoured target volumes and OAR was provided to participating centers. This is to control variations in contouring the target volumes and OARs by oncologists. The planner at each center was instructed to complete the treatment plan based on clinical practice with a given prescription, and the plan was analyzed against the planning goals provided. The quality of completed treatment plans was analyzed using the plan quality index (PQI), in which a score of 0 indicated that all dose objectives and constraints were achieved. A total of 23 plans were received from all participating centers comprising 14 VMAT, 7 IMRT, and 2 tomotherapy plans. The PQI indexes of these plans ranged from 0 to 0.65, indicating a wide variation of plan quality nationwide. Results also reported 5 out of 21 plans achieved all dose objectives and constraints showing more professional training is needed for planners in Malaysia. Understanding of treatment planning system and computational physics could also help in improving the quality of treatment plans for IMRT delivery.
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Wall PDH, Fontenot JD. Quality assurance-based optimization (QAO): Towards improving patient-specific quality assurance in volumetric modulated arc therapy plans using machine learning. Phys Med 2021; 87:136-143. [PMID: 33775567 DOI: 10.1016/j.ejmp.2021.03.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 03/01/2021] [Accepted: 03/09/2021] [Indexed: 10/21/2022] Open
Abstract
INTRODUCTION Previous literature has shown general trade-offs between plan complexity and resulting quality assurance (QA) outcomes. However, existing solutions for controlling this trade-off do not guarantee corresponding improvements in deliverability. Therefore, this work explored the feasibility of an optimization framework for directly maximizing predicted QA outcomes of plans without compromising the dosimetric quality of plans designed with an established knowledge-based planning (KBP) technique. MATERIALS AND METHODS A support vector machine (SVM) was developed - using a database of 500 previous VMAT plans - to predict gamma passing rates (GPRs; 3%/3mm percent dose-difference/distance-to-agreement with local normalization) based on selected complexity features. A heuristic, QA-based optimization (QAO) framework was devised by utilizing the SVM model to iteratively modify mechanical treatment features most commonly associated with suboptimal GPRs. Specifically, leaf gaps (LGs) <50 mm were widened by random amounts, which impacts all aperture-based complexity features. 13 prostate KBP-guided VMAT plans were optimized via QAO using user-specified maximum LG displacements before corresponding changes in predicted GPRs and dose were assessed. RESULTS Predicted GPRs increased by an average of 1.14 ± 1.25% (p = 0.006) with QAO using a 3 mm maximum random LG displacement. There were small differences in dose, resulting in similarly small changes in tumor control probability (maximum increase = 0.05%) and normal tissue complication probabilities in the bladder, rectum, and femoral heads (maximum decrease = 0.2% in the rectum). CONCLUSION This study explored the feasibility of QAO and warrants future investigations of further incorporating QA endpoints into plan optimization.
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Affiliation(s)
- Phillip D H Wall
- Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Tower Drive, Baton Rouge, LA 70803-4001, USA.
| | - Jonas D Fontenot
- Department of Physics and Astronomy, Louisiana State University and Agricultural and Mechanical College, 202 Tower Drive, Baton Rouge, LA 70803-4001, USA; Department of Physics, Mary Bird Perkins Cancer Center, 4950 Essen Lane, Baton Rouge, LA 70809, USA
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Momin S, Gräfe JL, Georgiou K, Khan RF. Photon beam energy dependent single-arc volumetric modulated arc optimization. Phys Med 2021; 82:122-133. [PMID: 33611049 DOI: 10.1016/j.ejmp.2021.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 12/26/2020] [Accepted: 02/06/2021] [Indexed: 11/16/2022] Open
Abstract
PURPOSE The purpose of this work was to present a new single-arc mixed photon (6&18MV) VMAT (SAMP) optimization framework that concurrently optimizes for two photon energies with corresponding partial arc lengths. METHODS AND MATERIALS Owing to simultaneous optimization of energy dependent intensity maps and corresponding arc locations, the proposed model poses nonlinearity. Unique relaxation constraints based on McCormick approximations were introduced for linearization. Energy dependent intensity maps were then decomposed to generate apertures. Feasibility of the proposed framework was tested on a sample of ten prostate cancer cases with lateral separation ranging from 34 cm (case no.1) to 52 cm (case no.6). The SAMP plans were compared against single energy (6MV) VMAT (SE) plans through dose volume histograms (DVHs) and radiobiological parameters including normal tissue complication probability (NTCP) and equivalent uniform dose (EUD). RESULTS The contribution of higher energy photon beam optimized by the algorithm demonstrated an increase for cases with a lateral separation >40 cm. SAMP-VMAT notably improved bladder and rectum sparing in large size cases. Compared to single energy, SAMP-VMAT plans reduced bladder and rectum NTCP in cases with large lateral separation. With the exception of one case, SAMP-VMAT either improved or maintained femoral heads compared to SE-VMAT. SAMP-VMAT reduced the nontarget tissue integral dose in all ten cases. CONCLUSIONS A single-arc VMAT optimization framework comprising mixed photon energy partial arcs was presented. Overall results underline the feasibility and potential of the proposed approach for improving OAR sparing in large size patients without compromising the target homogeneity and coverage.
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Affiliation(s)
- Shadab Momin
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA; Department of Physics, Ryerson University, Toronto, ON, Canada.
| | - James L Gräfe
- Department of Physics, Ryerson University, Toronto, ON, Canada
| | | | - Rao F Khan
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
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Ding S, Li Y, Liu H, Li R, Wang B, Zhang J, Chen Y, Huang X. Comparison of Intensity Modulated Radiotherapy Treatment Plans Between 1.5T MR-Linac and Conventional Linac. Technol Cancer Res Treat 2021; 20:1533033820985871. [PMID: 33472549 PMCID: PMC7829462 DOI: 10.1177/1533033820985871] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
In this study, we assess the dosimetric qualities and usability of planning for
1.5 T MR-Linac based intensity modulated radiotherapy (MRL-IMRT) for various
clinical sites in comparison with IMRT plans using a conventional linac. In
total of 30 patients with disease sites in the brain, esophagus, lung, rectum
and vertebra were re-planned retrospectively for simulated MRL-IMRT using the
Elekta Unity dedicated treatment planning system (TPS) Monaco (v5.40.01).
Currently, the step-and-shoot (ss) is the only delivery technique for IMRT
available on Unity. All patients were treated on an Elekta Versa HDTM
with IMRT using the dynamic multileaf collimator (dMLC) technique, and the plans
were designed using Monaco v5.11. For comparison, the same dMLC-IMRT plan was
recalculated with the same machine and TPS but only changing the technique to
step-and-shoot. The dosimetric qualities of the MRL-IMRT plans, to be evaluated
by the Dose Volume Histograms (DVH) metrics, Homogeneity Index and Conformality
Index, were compared with the clinical plans. The planning usability was
measured by the optimization time and the number of Monitor Units (MUs).
Comparing MRL-IMRT with conventional linac based plans, all created plans were
clinically equivalent to current clinical practice. However, MRL-IMRT plans had
higher dose to skin and larger low dose region of normal tissues. Furthermore,
MRL-IMRT plans had significantly reduced optimization time by comparing
conventional linac based plans. The number of MUs of MRL-IMRT was increased by
23% compared with ss-IMRT, and no difference from dMLC-IMRT. In conclusion,
clinically acceptable plans can be achieved with 1.5 T MR-Linac system for
multiple tumor sites. Given the differences in machine characteristics, some
minor differences in plan quality were found between MR-Linac plans and current
clinical practice and this should be considered in clinical practice.
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Affiliation(s)
- Shouliang Ding
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yongbao Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Hongdong Liu
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Rui Li
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Bin Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Jun Zhang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Yan Chen
- 35754Elekta (Shanghai) Instrument Ltd, China
| | - Xiaoyan Huang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, 71067Sun Yat-sen University Cancer Center, Guangzhou, China
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Hernandez V, Hansen CR, Widesott L, Bäck A, Canters R, Fusella M, Götstedt J, Jurado-Bruggeman D, Mukumoto N, Kaplan LP, Koniarová I, Piotrowski T, Placidi L, Vaniqui A, Jornet N. What is plan quality in radiotherapy? The importance of evaluating dose metrics, complexity, and robustness of treatment plans. Radiother Oncol 2020; 153:26-33. [PMID: 32987045 DOI: 10.1016/j.radonc.2020.09.038] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/17/2020] [Accepted: 09/17/2020] [Indexed: 12/25/2022]
Abstract
Plan evaluation is a key step in the radiotherapy treatment workflow. Central to this step is the assessment of treatment plan quality. Hence, it is important to agree on what we mean by plan quality and to be fully aware of which parameters it depends on. We understand plan quality in radiotherapy as the clinical suitability of the delivered dose distribution that can be realistically expected from a treatment plan. Plan quality is commonly assessed by evaluating the dose distribution calculated by the treatment planning system (TPS). Evaluating the 3D dose distribution is not easy, however; it is hard to fully evaluate its spatial characteristics and we still lack the knowledge for personalising the prediction of the clinical outcome based on individual patient characteristics. This advocates for standardisation and systematic collection of clinical data and outcomes after radiotherapy. Additionally, the calculated dose distribution is not exactly the dose delivered to the patient due to uncertainties in the dose calculation and the treatment delivery, including variations in the patient set-up and anatomy. Consequently, plan quality also depends on the robustness and complexity of the treatment plan. We believe that future work and consensus on the best metrics for quality indices are required. Better tools are needed in TPSs for the evaluation of dose distributions, for the robust evaluation and optimisation of treatment plans, and for controlling and reporting plan complexity. Implementation of such tools and a better understanding of these concepts will facilitate the handling of these characteristics in clinical practice and be helpful to increase the overall quality of treatment plans in radiotherapy.
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Affiliation(s)
- Victor Hernandez
- Department of Medical Physics, Hospital Sant Joan de Reus, IISPV, Spain.
| | - Christian Rønn Hansen
- Laboratory of Radiation Physics, Odense University Hospital, Denmark; Institute of Clinical Research, University of Southern Denmark, Denmark; Danish Centre for Particle Therapy, Aarhus University Hospital, Denmark
| | | | - Anna Bäck
- Department of Therapeutic Radiation Physics, Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Academy at the University of Gothenburg, Sweden
| | - Richard Canters
- Department of Radiation Oncology (Maastro), GROW School for Oncology, Maastricht University Medical Centre+, The Netherlands
| | - Marco Fusella
- Medical Physics Department, Veneto Institute of Oncology IOV - IRCCS, Padua, Italy
| | - Julia Götstedt
- Department of Radiation Physics, University of Gothenburg, Göteborg, Sweden
| | - Diego Jurado-Bruggeman
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Girona, Spain
| | - Nobutaka Mukumoto
- Department of Radiation Oncology and Image-applied Therapy, Graduate, School of Medicine, Kyoto University, Japan
| | | | - Irena Koniarová
- National Radiation Protection Institute, Prague, Czech Republic
| | - Tomasz Piotrowski
- Department of Electroradiology, Poznań University of Medical Sciences, Poznań, Poland; Department of Medical Physics, Greater Poland Cancer Centre, Poznań, Poland
| | - Lorenzo Placidi
- Fondazione Policlinico Universitario "A. Gemelli" IRCCS, UOC Radioterapia Oncologica, Dipartimento di Diagnostica per Immagini, Radioterapia Oncologica ed Ematologia, Roma, Italy
| | - Ana Vaniqui
- Department of Radiation Oncology (Maastro), GROW School for Oncology, Maastricht University Medical Centre+, The Netherlands
| | - Nuria Jornet
- Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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Lobb EC, Degnan M. Comparison of VMAT complexity-reduction strategies for single-target cranial radiosurgery with the Eclipse treatment planning system. J Appl Clin Med Phys 2020; 21:97-108. [PMID: 32920991 PMCID: PMC7592979 DOI: 10.1002/acm2.13014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/23/2020] [Accepted: 07/28/2020] [Indexed: 11/11/2022] Open
Abstract
Complexity in MLC‐based radiosurgery treatment delivery can be characterized by the efficiency of monitor unit (MU) utilization and the average MLC leaf separation distance for a treatment plan. A reduction in plan complexity may be desirable if plan quality is not impacted. In this study, a number of strategies are explored to determine how plan quality is affected by efforts to reduce plan complexity. Ten radiosurgery cases of varying complexity are retrospectively planned using six optimization strategies: an unconstrained volumetric modulated arc therapy (VMAT) technique, a MU‐constrained VMAT technique, three techniques using various strengths of the aperture shape controller (ASC), and a hybrid technique consisting of a final‐stage VMAT optimization applied to a dynamic conformal arc leaf sequence (ODCA). The plans are compared in terms of MU efficiency, MLC leaf‐separation, conformity index (CI), gradient index (GI), and QA measurement results. The five VMAT techniques exhibited only minor differences in CI and GI values, though the ASC and MU‐constrained techniques did require 6–20% fewer MU and had mean field apertures 5–19% larger. On average, the ODCA technique had CI values 3.5% lower and GI values 1.0–2.5% higher than the VMAT techniques, but also had a mean field aperture 24–47% larger and required 16–32% fewer MU. The QA measurement results showed a 0.61% variation in mean per‐field 2%/1 mm gamma passing rates across all techniques (range 96.81%–97.42%), with no observed correlation between passing rate and technique. For simple targets, the ODCA technique achieved CI results that were equivalent to the unconstrained VMAT technique with an average 30% reduction in required MU, an average 50% increase in mean leaf separation distance, and brain V12Gy values within 0.38 cc of the VMAT technique for targets up to approximately 2 cm diameter. For MLC‐based single‐target radiosurgery, plan complexity can often be significantly reduced without an equivalent reduction in plan quality.
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Affiliation(s)
- Eric C Lobb
- Department of Radiation Oncology, Ascension NE Wisconsin - St. Elizabeth Hospital, Appleton, WI, USA
| | - Michael Degnan
- Department of Radiation Oncology, The Ohio State University Comprehensive Cancer Center, Columbus, OH, USA
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23
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Zhang Q, Ou L, Peng Y, Yu H, Wang L, Zhang S. Evaluation of automatic VMAT plans in locally advanced nasopharyngeal carcinoma. Strahlenther Onkol 2020; 197:177-187. [PMID: 32488293 DOI: 10.1007/s00066-020-01631-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/04/2020] [Indexed: 11/27/2022]
Abstract
OBJECTIVE This study aimed to evaluate the quality of locally advanced nasopharyngeal carcinoma (NPC) radiotherapy plans generated by the automated planning module of a commercial treatment planning system (TPS). METHODS Data of 30 patients with locally advanced NPC were retrospectively investigated. For each patient, volumetric modulated arc therapy (VMAT) plans with double arcs were generated manually by experienced physicists and automatically in the Pinnacle3 Auto-Planning module (Philips Medical Systems, Fitchburg, WI, USA). The anatomic distance between the second clinical target volume (CTV2) and the pons of the brainstem, and the T category of disease were factored into the evaluation. Dosimetric verification was evaluated in terms of gamma pass rate. Target coverage, sparing of organs at risk (OARs), and monitor units were evaluated and compared between the manual and automatic VMAT plans. RESULTS Not all treatment plans fully met the dose objectives for planning target volumes (PTVs) and OARs, particularly in T4 patients. Overall, automatic VMAT provides a comparable or superior plan quality to manual VMAT in most cases. In stratified analysis, plan quality is mainly independent on T category but is also affected by anatomic distance. If the anatomic distance is less than 5 mm, the automatic VMAT plan quality is equal or even inferior to manual VMAT performed by experienced physicists. Conversely, if the anatomic distance is greater than 5 mm, the automatic VMAT plan quality is superior to manual VMAT. Gamma pass rates for quality assurance are similar between manual and automatic VMAT plans for the former case, but significantly higher in automatic VMAT for the latter. CONCLUSION The selection of manual versus automatic VMAT planning in locally advanced NPC should be made individually based on the anatomic distance, rather than blindly and habitually, since automatic VMAT is not good enough to completely replace manual VMAT.
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Affiliation(s)
- Quanbin Zhang
- Radiotherapy center, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Liya Ou
- Guangzhou Medical University, Guangzhou, China.
| | - Yingying Peng
- Radiotherapy center, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Hui Yu
- Radiotherapy center, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Linjing Wang
- Radiotherapy center, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Shuxu Zhang
- Radiotherapy center, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China.
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Babier A, Mahmood R, McNiven AL, Diamant A, Chan TC. The importance of evaluating the complete automated knowledge-based planning pipeline. Phys Med 2020; 72:73-79. [DOI: 10.1016/j.ejmp.2020.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/06/2020] [Accepted: 03/17/2020] [Indexed: 11/30/2022] Open
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25
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Kamperis E, Kodona C, Hatziioannou K, Giannouzakos V. Complexity in Radiation Therapy: It's Complicated. Int J Radiat Oncol Biol Phys 2020; 106:182-184. [DOI: 10.1016/j.ijrobp.2019.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 08/29/2019] [Accepted: 09/06/2019] [Indexed: 12/11/2022]
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26
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Wall PDH, Fontenot JD. Evaluation of complexity and deliverability of prostate cancer treatment plans designed with a knowledge-based VMAT planning technique. J Appl Clin Med Phys 2020; 21:69-77. [PMID: 31816175 PMCID: PMC6964749 DOI: 10.1002/acm2.12790] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 10/04/2019] [Accepted: 11/18/2019] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Knowledge-based planning (KBP) techniques have been reported to improve plan quality, efficiency, and consistency in radiation therapy. However, plan complexity and deliverability have not been addressed previously for treatment plans guided by an established in-house KBP system. The purpose of this work was to assess dosimetric, mechanical, and delivery properties of plans designed with a common KBP method for prostate cases treated via volumetric modulated arc therapy (VMAT). METHODS Thirty-one prostate patients previously treated with VMAT were replanned with an in-house KBP method based on the overlap volume histogram. VMAT plan complexities of the KBP plans and the reference clinical plans were quantified via monitor units, modulation complexity scores, the edge metric, and average leaf motion per degree of gantry rotation. Each set of plans was delivered to the same diode array and agreement between computed and measured dose distributions was evaluated using the gamma index. Varying percent dose-difference (1-3%) and distance-to-agreement (1 mm to 3 mm) thresholds were assessed for gamma analyses. RESULTS Knowledge-based planning (KBP) plans achieved average reductions of 6.4 Gy (P < 0.001) and 8.2 Gy (P < 0.001) in mean bladder and rectum dose compared to reference plans, while maintaining clinically acceptable target dose. However, KBP plans were significantly more complex than reference plans in each evaluated metric (P < 0.001). KBP plans also showed significant reductions (P < 0.05) in gamma passing rates at each evaluated criterion compared to reference plans. CONCLUSIONS While KBP plans had significantly reduced bladder and rectum dose, they were significantly more complex and had significantly worse quality assurance outcomes than reference plans. These results suggest caution should be taken when implementing an in-house KBP technique.
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Affiliation(s)
- Phillip D. H. Wall
- Department of Physics and AstronomyLouisiana State University and Agricultural and Mechanical CollegeBaton RougeLAUSA
| | - Jonas D. Fontenot
- Department of Physics and AstronomyLouisiana State University and Agricultural and Mechanical CollegeBaton RougeLAUSA
- Department of PhysicsMary Bird Perkins Cancer CenterBaton RougeLAUSA
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Knowledge‐based automated planning with three‐dimensional generative adversarial networks. Med Phys 2019; 47:297-306. [DOI: 10.1002/mp.13896] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 07/29/2019] [Accepted: 10/16/2019] [Indexed: 01/28/2023] Open
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Li J, Zhang X, Li J, Jiang R, Sui J, Chan MF, Yang R. Impact of delivery characteristics on dose delivery accuracy of volumetric modulated arc therapy for different treatment sites. JOURNAL OF RADIATION RESEARCH 2019; 60:603-611. [PMID: 31147684 PMCID: PMC6805974 DOI: 10.1093/jrr/rrz033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 03/31/2019] [Indexed: 06/09/2023]
Abstract
This study aimed to investigate the impact of delivery characteristics on the dose delivery accuracy of volumetric modulated arc therapy (VMAT) for different treatment sites. The pretreatment quality assurance (QA) results of 344 VMAT patients diagnosed with gynecological (GYN), head and neck (H&N), rectal or prostate cancer were randomly chosen in this study. Ten metrics reflecting VMAT delivery characteristics were extracted from the QA plans. Compared with GYN and rectal plans, H&N and prostate plans had higher aperture complexity and monitor units (MU), and smaller aperture area. Prostate plans had the smallest aperture area and lowest leaf speed compared with other plans (P < 0.001). No differences in gantry speed were found among the four sites. The gamma passing rates (GPRs) of GYN, rectal and H&N plans were inversely associated with union aperture area (UAA) and leaf speed (Pearson's r: -0.39 to -0.68). GPRs of prostate plans were inversely correlated with aperture complexity, MU and small aperture score (SAS) (absolute Pearson's r: 0.34 to 0.49). Significant differences in GPR between high SAS and low SAS subgroups were found only when leaf speed was <0.42 cm s-1 (P < 0.001). No association of GPR with gantry speed was found in four sites. Leaf speed was more strongly associated with UAA. Aperture complexity and MU were more strongly associated with SAS. VMAT plans from different sites have distinct delivery characteristics. Affecting dose delivery accuracy, leaf speed is the key factor for GYN, rectal and H&N plans, while aperture complexity, MU and small apertures have a higher influence on prostate plans.
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Affiliation(s)
- Jiaqi Li
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Xile Zhang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Jun Li
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Rongtao Jiang
- Brainnetome Center & National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Jing Sui
- Brainnetome Center & National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Maria F Chan
- Medical Physics Department, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ruijie Yang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
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Chiavassa S, Bessieres I, Edouard M, Mathot M, Moignier A. Complexity metrics for IMRT and VMAT plans: a review of current literature and applications. Br J Radiol 2019; 92:20190270. [PMID: 31295002 PMCID: PMC6774599 DOI: 10.1259/bjr.20190270] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/04/2019] [Accepted: 07/09/2019] [Indexed: 12/21/2022] Open
Abstract
Modulated radiotherapy with multileaf collimators is widely used to improve target conformity and normal tissue sparing. This introduced an additional degree of complexity, studied by multiple teams through different properties. Three categories of complexity metrics were considered in this review: fluence, deliverability and accuracy metrics. The first part of this review is dedicated to the inventory of these complexity metrics. Different applications of these metrics emerged. Influencing the optimizer by integrating complexity metrics into the cost function has been little explored and requires more investigations. In modern treatment planning system, it remains confined to MUs or treatment time limitation. A large majority of studies calculated metrics only for analysis, without plan modification. The main application was to streamline the patient specific quality assurance workload, investigating the capability of complexity metrics to predict patient specific quality assurance results. Additionally complexity metrics were used to analyze behaviour of TPS optimizer, compare TPS, operators and plan properties, and perform multicentre audit. Their potential was also explored in the context of adaptive radiotherapy and automation planning. The second part of the review gives an overview of these studies based on the complexity metrics.
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Affiliation(s)
- Sophie Chiavassa
- Department of Medical Physics, Institut de Cancérologie de l’Ouest Centre René Gauducheau, 44805 Saint-Herblain, France
| | - Igor Bessieres
- Departement of Medical Physics, Centre Georges-François Leclerc, 1 rue Professeur Marion, 21000 Dijon, France
| | - Magali Edouard
- Department of Radiation Oncology, Gustave Roussy, 114 rue Édouard-Vaillant, 94805 Villejuif, France
| | - Michel Mathot
- Liege University Hospital, Domaine du Sart Tilman - B.35 - B-4000 LIEGE1, Belgium
| | - Alexandra Moignier
- Department of Medical Physics, Institut de Cancérologie de l’Ouest Centre René Gauducheau, 44805 Saint-Herblain, France
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Schipaanboord BWK, Breedveld S, Rossi L, Keijzer M, Heijmen B. Automated prioritised 3D dose-based MLC segment generation for step-and-shoot IMRT. ACTA ACUST UNITED AC 2019; 64:165013. [DOI: 10.1088/1361-6560/ab1df9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lu L, Sheng Y, Donaghue J, Liu Shen Z, Kolar M, Wu QJ, Xia P. Three IMRT advanced planning tools: A multi-institutional side-by-side comparison. J Appl Clin Med Phys 2019; 20:65-77. [PMID: 31364798 PMCID: PMC6698808 DOI: 10.1002/acm2.12679] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 05/17/2019] [Accepted: 06/19/2019] [Indexed: 11/25/2022] Open
Abstract
Purpose To assess three advanced radiation therapy treatment planning tools on the intensity‐modulated radiation therapy (IMRT) quality and consistency when compared to the clinically approved plans, referred as manual plans, which were planned without using any of these advanced planning tools. Materials and Methods Three advanced radiation therapy treatment planning tools, including auto‐planning, knowledge‐based planning, and multiple criteria optimization, were assessed on 20 previously treated clinical cases. Three institutions participated in this study, each with expertise in one of these tools. The twenty cases were retrospectively selected from Cleveland Clinic, including five head‐and‐neck (HN) cases, five brain cases, five prostate with pelvic lymph nodes cases, and five spine cases. A set of general planning objectives and organs‐at‐risk (OAR) dose constraints for each disease site from Cleveland Clinic was shared with other two institutions. A total of 60 IMRT research plans (20 from each institution) were designed with the same beam configuration as in the respective manual plans. For each disease site, detailed isodoseline distributions and dose volume histograms for a randomly selected representative case were compared among the three research plans and manual plan. In addition, dosimetric endpoints of five cases for each site were compared. Results Compared to the manual plans, the research plans using advanced tools showed substantial improvement for the HN patient cases, including the maximum dose to the spinal cord and brainstem and mean dose to the parotid glands. For the brain, prostate, and spine cases, the four types of plans were comparable based on dosimetric endpoint comparisons. Conclusion With minimal planner interventions, advanced treatment planning tools are clinically useful, producing a plan quality similarly to or better than manual plans, improving plan consistency. For difficult cases such as HN cancer, advanced planning tools can further reduce radiation doses to numerous OARs while delivering adequate dose to the tumor targets.
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Affiliation(s)
- Lan Lu
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, USA
| | - Yang Sheng
- Department of Radiation Oncology, Duke University, Durham, NC, USA
| | - Jeremy Donaghue
- Department of Radiation Oncology, Akron General Hospital, Akron, OH, USA
| | - Zhilei Liu Shen
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, USA
| | - Matt Kolar
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, USA
| | - Q Jackie Wu
- Department of Radiation Oncology, Duke University, Durham, NC, USA
| | - Ping Xia
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic, Cleveland, OH, USA
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Bokrantz R, Amerongen JH, Craft D. Technical Note: Improving VMAT delivery efficiency by optimizing the dynamic collimator trajectory. Med Phys 2019; 46:3877-3882. [DOI: 10.1002/mp.13671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 11/06/2022] Open
Affiliation(s)
| | - Jacobus H.M. Amerongen
- Department of Econometrics and Operations Research/Center for Economic Research (CentER) Tilburg University TilburgLE 5000The Netherlands
| | - David Craft
- Department of Radiation Oncology Massachusetts General Hospital and Harvard Medical School BostonMA 02114USA
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Momin S, Gräfe J, Georgiou K, Khan R. Simultaneous optimization of mixed photon energy beams in volumetric modulated arc therapy. Med Phys 2019; 46:3844-3863. [PMID: 31276215 DOI: 10.1002/mp.13700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Despite the availability of multiple energy photon beams on clinical linear accelerators, volumetric modulated arc therapy (VMAT) optimization is currently limited to a single photon beam. The purpose of this work was to present a proof-of-principle study on an algorithm for simultaneous optimization of mixed photon beams for VMAT (MP - VMAT), utilizing an additional photon energy as an additional degree of freedom. METHODS The MP - VMAT optimization algorithm is presented as a two-step heuristic approach. First, a convex linear programming problem is solved for simultaneous optimization of nonuniform dual energy intensity maps (DEIMs) for an angular resolution of 36 equi-spaced beam segments. Subsequently, for a given gantry speed schedule, the second step aims to best replicate each DEIM by dispersing MP - VMAT apertures along with their corresponding intensities over their respective beam segment. This constitutes a nonlinear problem, which is linearized using McCormick relaxation. The final large-scale mixed integer linear programming (MILP) dispersion model ensures a contiguous and smooth transition of multileaf collimators (MLCs) from one beam segment to the next. To demonstrate the proof-of-principle, we first compared the quality of dose volume histograms (DVHs) of MP - VMAT to the ones calculated from 36 DEIMs following the step 1 of MP - VMAT model. Additionally, the MLCs motion violations were evaluated for the complete 360° gantry rotation for gantry speeds ranging from 1 to 6° per second. The quality of MP - VMAT plans were also compared to conventional single energy VMAT plans via DVH, homogeneity index (HI), and conformity number (CN) for two prostate cases. RESULTS The MP - VMAT model resulted in a successful convergence of DVHs relative to the ones from DEIMs with HI and CN of 0.05 and 0.9, respectively, for 1 and 2° per second gantry speed schedules. In replicating the DEIMs, the MILP dispersion model was able to achieve optimality for almost all segments at 1° per second and for majority of segments at 2° per second. Although, DVHs quality was slightly inferior for 3° per second gantry speed, the target conformity of 0.9 and heterogeneity of 0.08 were achievable even for the suboptimal solutions. No violations of the MLC constraints were observed throughout the complete 360 degree arc rotation for any gantry speed schedule, thereby confirming MILP dispersion model. For the two prostate cases, the results showed MP - VMAT's ability to achieve substantial dose reduction in rectum and bladder while yielding similar target coverage compared to single energy VMAT. Bladder volume was mostly spared in low-to-intermediate dose region. Rectal volume sparing (3 % to 12 %) was observed in the intermediate (from 25 to 50 Gy) dose region. CONCLUSION We demonstrate the first formalism of a large-scale simultaneous optimization of mixed photon energy beams for VMAT. Dosimetric comparison of MP - VMAT to single energy VMAT demonstrated potential advantages of using mixed photon energy beams for prostate plans, thus providing an impetus for further testing on a large clinical cohort.
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Affiliation(s)
- Shadab Momin
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA.,Department of Physics, Ryerson University, Toronto, ON, Canada
| | - James Gräfe
- Department of Physics, Ryerson University, Toronto, ON, Canada
| | | | - Rao Khan
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO, USA
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Chuter R, van Herk M, Akhiat H, Voet P, MacKay R, Choudhury A, McWilliam A. Comparison of intensity modulated radiotherapy plan optimisation methods for a 1.5 T MR-Linac. J Appl Clin Med Phys 2019; 20:43-49. [PMID: 30371972 PMCID: PMC6333134 DOI: 10.1002/acm2.12475] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/25/2018] [Accepted: 09/09/2018] [Indexed: 11/10/2022] Open
Abstract
PURPOSE For the 1.5 T Elekta MR-Linac it is essential that the optimisation of a treatment plan accounts for the electron return effect on the planned dose distribution. The ability of two algorithms for the first stage fluence optimisation, pencil beam (PB) and Monte Carlo (MC), to produce acceptable plan quality was investigated. Optimisation time for each algorithm was also compared. METHODS Ten head and neck patients, ten lung patients and five prostate patients were selected from the clinical archive. These were retrospectively planned using a research version of Monaco with both the PB and MC algorithms for the fluence optimisation stage. After full optimisation DVH parameters, optimisation time and the number of Monitor Units (MU) as a measure of plan complexity were extracted. RESULTS There were no clinically significant differences between any of the DVH parameters studied or the total number of MUs between using PB or MC for stage 1 optimisation across the three patient groups. However, planning time increased by a factor of ten using MC algorithms for stage 1. CONCLUSION The use of MC calculations compared to PB, for stage 1 fluence optimisation, results in increased planning time without clinical improvement in plan quality or reduction in complexity and is therefore not necessary.
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Affiliation(s)
- Robert Chuter
- Christie Medical Physics and Engineering (CMPE)The Christie NHS Foundation TrustManchesterUK
- Division of Cancer SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Marcel van Herk
- Division of Cancer SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- NIHR Manchester Biomedical Research CentreCentral Manchester University Hospitals NHS Foundation TrustManchester Academic Health Science CentreManchesterUK
| | | | | | - Ranald MacKay
- Christie Medical Physics and Engineering (CMPE)The Christie NHS Foundation TrustManchesterUK
| | - Ananya Choudhury
- Division of Cancer SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Clinical OncologyThe Christie NHS Foundation TrustManchesterUK
| | - Alan McWilliam
- Christie Medical Physics and Engineering (CMPE)The Christie NHS Foundation TrustManchesterUK
- Division of Cancer SciencesFaculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
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Miguel-Chumacero E, Currie G, Johnston A, Currie S. Effectiveness of Multi-Criteria Optimization-based Trade-Off exploration in combination with RapidPlan for head & neck radiotherapy planning. Radiat Oncol 2018; 13:229. [PMID: 30470254 PMCID: PMC6251185 DOI: 10.1186/s13014-018-1175-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 11/06/2018] [Indexed: 11/11/2022] Open
Abstract
Background A new strategy is introduced combining the use of Multi-Criteria Optimization-based Trade-Off Exploration (TO) and RapidPlan™ (RP) for the selection of optimisation parameters that improve the trade-off between sparing of organs at risk (OAR) and target coverage for head and neck radiotherapy planning. Using both approaches simultaneously; three different workflows were proposed for the optimisation process of volumetric-modulated arc therapy (VMAT) plans. The generated plans were compared to the clinical plans and the plans that resulted using RP and TO individually. Methods Twenty clinical VMAT plans previously administered were selected. Five additional plans were created for each patient: a clinical plan further optimised with TO (Clin+TO); two plans generated by in-house built RP models, RP_1 with the model built with VMAT clinical plans and RP_TO with the model built with VMAT plans optimised by TO. Finally, these last two plans were additionally optimised with TO for the creation of the plans RP_1 + TO and RP_TO+ respectively. The TO management was standardised to maximise the sparing of the parotid glands without compromising a clinically acceptable PTV coverage. Resulting plans were inter-compared based on dose-volume parameters for OAR and PTVs, target homogeneity, conformity, and plans complexity and deliverability. Results The plans optimised using TO in combination with RP showed significantly improved OAR sparing while maintaining comparable target dose coverage to the clinical plans. The largest OAR sparing compared to the clinical plans was achieved by the RP_TO+ plans, which reported a mean parotid dose average of 15.0 ± 4.6 Gy vs 22.9 ± 5.5 Gy (left) and 17.1 ± 5.0 Gy vs 24.8 ± 5.8 Gy (right). However, at the same time, RP_TO+ showed a slight dose reduction for the 99% volume of the nodal PTV and an increase for the 95% (when comparing to the clinical plans 76.0 ± 1.2 vs 77.4 ± 0.6 and 80.9 ± 0.9 vs 79.7 ± 0.4) but remained within clinical acceptance. Plans optimised with RP and TO combined, showed an increase in complexity but were proven to be deliverable. Conclusion The use of TO combined with RP during the optimisation of VMAT plans enhanced plan quality the most. For the RP_TO+ plans, acceptance of a slight deterioration in nodal PTV allowed the largest reduction in OAR dose to be achieved.
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Affiliation(s)
- Eliane Miguel-Chumacero
- Beatson West of Scotland Cancer Centre, Radiotherapy Physics, NHS Greater Glasgow and Clyde, 1053 Great Western Road, Glasgow, G12 0YN, UK.
| | - Garry Currie
- Beatson West of Scotland Cancer Centre, Radiotherapy Physics, NHS Greater Glasgow and Clyde, 1053 Great Western Road, Glasgow, G12 0YN, UK
| | - Abigail Johnston
- Beatson West of Scotland Cancer Centre, Radiotherapy Physics, NHS Greater Glasgow and Clyde, 1053 Great Western Road, Glasgow, G12 0YN, UK
| | - Suzanne Currie
- Beatson West of Scotland Cancer Centre, Radiotherapy Physics, NHS Greater Glasgow and Clyde, 1053 Great Western Road, Glasgow, G12 0YN, UK
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Tomori S, Kadoya N, Takayama Y, Kajikawa T, Shima K, Narazaki K, Jingu K. A deep learning-based prediction model for gamma evaluation in patient-specific quality assurance. Med Phys 2018; 45:4055-4065. [PMID: 30066388 DOI: 10.1002/mp.13112] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 01/02/2023] Open
Abstract
PURPOSE Patient-specific quality assurance (QA) measurement is conducted to confirm the accuracy of dose delivery. However, measurement is time-consuming and places a heavy workload on the medical physicists and radiological technologists. In this study, we proposed a prediction model for gamma evaluation, based on deep learning. We applied the model to a QA measurement dataset of prostate cancer cases to evaluate its practicality. METHODS Sixty pretreatment verification plans from prostate cancer patients treated using intensity modulated radiation therapy were collected. Fifteen-layer convolutional neural networks (CNN) were developed to learn the sagittal planar dose distributions from a RT-3000 QA phantom (R-TECH.INC., Tokyo, Japan). The percentage gamma passing rate (GPR) was measured using GAFCHROMIC EBT3 film (Ashland Specialty Ingredients, Covington, USA). The input training data also included the volume of the PTV (planning target volume), rectum, and overlapping region, measured in cm3 , and the monitor unit values for each field. The network produced predicted GPR values at four criteria: 2%(global)/2 mm, 3%(global)/2 mm, 2%(global)/3 mm, and 3%(global)/3 mm. Adam, an algorithm for first-order gradient-based optimization of stochastic objective functions, was used for learning and for optimizing the CNN-based model. Fivefold cross-validation was applied to validate the performance of the proposed method. Forty cases were used for training and validation set in fivefold cross-validation, and the remaining 20 cases were used for the test set. The predicted and measured GPR values were compared. RESULTS A linear relationship was found between the measured and predicted values, for each of the four criteria. Spearman rank correlation coefficients in validation set between measured and predicted GPR values at four criteria were 0.73 at 2%/2 mm, 0.72 at 3%/2 mm, 0.74 at 2%/3 mm, and 0.65 at 3%/3 mm, respectively (P < 0.01). The Spearman rank correlation coefficients in the test set were 0.62 (P < 0.01) at 2%/2 mm, 0.56 (P < 0.01) at 3%/2 mm, 0.51 (P = 0.02) at 2%/3 mm, and 0.32 (P = 0.16) at 3%/3 mm. These results demonstrated a strong or moderate correlation between the predicted and measured values. CONCLUSIONS We developed a CNN-based prediction model for patient-specific QA of dose distribution in prostate treatment. Our results suggest that deep learning may provide a useful prediction model for gamma evaluation of patient-specific QA in prostate treatment planning.
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Affiliation(s)
- Seiji Tomori
- Department of Radiology, National Hospital Organization Sendai Medical Center, Sendai, Miyagi, 983-8520, Japan
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Noriyuki Kadoya
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Yoshiki Takayama
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Tomohiro Kajikawa
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
| | - Katsumi Shima
- Department of Radiology, National Hospital Organization Hakodate National Hospital, Hakodate, Hokkaido, 041-8512, Japan
| | - Kakutarou Narazaki
- Department of Radiology, National Hospital Organization Sendai Medical Center, Sendai, Miyagi, 983-8520, Japan
| | - Keiichi Jingu
- Department of Radiation Oncology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, 980-8574, Japan
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Babier A, Boutilier JJ, Sharpe MB, McNiven AL, Chan TCY. Inverse optimization of objective function weights for treatment planning using clinical dose-volume histograms. ACTA ACUST UNITED AC 2018; 63:105004. [DOI: 10.1088/1361-6560/aabd14] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Babier A, Boutilier JJ, McNiven AL, Chan TC. Knowledge‐based automated planning for oropharyngeal cancer. Med Phys 2018; 45:2875-2883. [DOI: 10.1002/mp.12930] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 03/12/2018] [Accepted: 04/05/2018] [Indexed: 11/10/2022] Open
Affiliation(s)
- Aaron Babier
- Department of Mechanical and Industrial Engineering University of Toronto 5 King's College Road Toronto M5S 3G8 ONCanada
| | - Justin J. Boutilier
- Department of Mechanical and Industrial Engineering University of Toronto 5 King's College Road Toronto M5S 3G8 ONCanada
| | - Andrea L. McNiven
- Radiation Medicine Program UHN Princess Margaret Cancer Centre 610 University of Avenue Toronto M5T 2M9 ONCanada
- Department of Radiation Oncology University of Toronto 148 ‐ 150 College Street Toronto M5S 3S2 ONCanada
| | - Timothy C.Y. Chan
- Department of Mechanical and Industrial Engineering University of Toronto 5 King's College Road Toronto M5S 3G8 ONCanada
- Techna Institute for the Advancement of Technology for Health 124 ‐ 100 College Street Toronto M5G 1L5 ONCanada
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Adibi A, Salari E. Spatiotemporal radiotherapy planning using a global optimization approach. ACTA ACUST UNITED AC 2018; 63:035040. [DOI: 10.1088/1361-6560/aaa729] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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40
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Pogson EM, Aruguman S, Hansen CR, Currie M, Oborn BM, Blake SJ, Juresic J, Ochoa C, Yakobi J, Haman A, Trtovac A, Carolan M, Holloway L, Thwaites DI. Multi-institutional comparison of simulated treatment delivery errors in ssIMRT, manually planned VMAT and autoplan-VMAT plans for nasopharyngeal radiotherapy. Phys Med 2017; 42:55-66. [DOI: 10.1016/j.ejmp.2017.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/03/2017] [Accepted: 08/20/2017] [Indexed: 11/25/2022] Open
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Balvert M, Craft D. Fast approximate delivery of fluence maps for IMRT and VMAT. Phys Med Biol 2017; 62:1225-1247. [DOI: 10.1088/1361-6560/aa56b6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Young MR, Craft DL, Colbert CM, Remillard K, Vanbenthuysen L, Wang Y. Volumetric-modulated arc therapy using multicriteria optimization for body and extremity sarcoma. J Appl Clin Med Phys 2016; 17:283-291. [PMID: 27929501 PMCID: PMC5690529 DOI: 10.1120/jacmp.v17i6.6547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/29/2016] [Accepted: 08/26/2016] [Indexed: 11/23/2022] Open
Abstract
This study evaluates the implementation of volumetric‐modulated arc therapy (VMAT) using multicriteria optimization (MCO) in the RayStation treatment planning system (TPS) for complex sites, namely extremity and body sarcoma. The VMAT‐MCO algorithm implemented in RayStation is newly developed and requires an integrated, comprehensive analysis of plan generation, delivery, and treatment efficiency. Ten patients previously treated by intensity‐modulated radiation therapy (IMRT) with MCO were randomly selected and replanned using VMAT‐MCO. The plan quality was compared using homogeneity index (HI) and conformity index (CI) of the planning target volume (PTV) and dose sparing of organs at risk (OARs). Given the diversity of the tumor location, the 10 plans did not have a common OAR except for skin. The skin D50 and Dmean was directly compared between VMAT‐MCO and IMRT‐MCO. Additional OAR dose points were compared on a plan‐by‐plan basis. The treatment efficiency was compared using plan monitor units (MU) and net beam‐on time. Plan quality assurance was performed using the Sun Nuclear ArcCHECK phantom and a gamma criteria of 3%/3 mm. No statistically significant differences were found between VMAT‐ and IMRT‐MCO for HI and CI of the PTV or D50 and Dmean to the skin. The VMAT‐MCO plans showed general improvements in sparing to OARs. The VMAT‐MCO plan set showed statistically significant improvements over the IMRT‐MCO set in treatment efficiency per plan MU (p<0.05) and net beam‐on time (p<0.01). The VMAT‐MCO plan deliverability was validated. Similar gamma passing rates were observed for the two modalities. This study verifies the suitability of VMAT‐MCO for sarcoma cancer and highlighted the comparability in plan quality and improvement in treatment efficiency offered by VMAT‐MCO as compared to IMRT‐MCO. PACS number(s): separated by commas 87.55.D, 87.55.de, 87.55.Qr
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Affiliation(s)
- Michael R Young
- Massachusetts General Hospital and Harvard Medical School; University of Massachusetts.
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Müller BS, Wilkens JJ. Prioritized efficiency optimization for intensity modulated proton therapy. Phys Med Biol 2016; 61:8249-8265. [DOI: 10.1088/0031-9155/61/23/8249] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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McGeachy P, Villarreal-Barajas JE, Zinchenko Y, Khan R. Modulated photon radiotherapy (XMRT): an algorithm for the simultaneous optimization of photon beamlet energy and intensity in external beam radiotherapy (EBRT) planning. Phys Med Biol 2016; 61:1476-98. [PMID: 26808280 DOI: 10.1088/0031-9155/61/4/1476] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
This is a proof of principle study on an algorithm for optimizing external beam radiotherapy in terms of both photon beamlet energy and fluence. This simultaneous beamlet energy and fluence optimization is denoted modulated photon radiotherapy (XMRT). XMRT is compared with single-energy intensity modulated radiotherapy (IMRT) for five clinically relevant test geometries to determine whether treating beamlet energy as a decision variable improves the dose distributions. All test geometries were modelled in a cylindrical water phantom. XMRT optimized the fluence for 6 and 18 MV beamlets while IMRT optimized with only 6 MV and only 18 MV. CERR (computational environment for radiotherapy research) was used to calculate the dose deposition matrices and the resulting dose for XMRT and IMRT solutions. Solutions were compared via their dose volume histograms and dose metrics, such as the mean, maximum, and minimum doses for each structure. The homogeneity index (HI) and conformity number (CN) were calculated to assess the quality of the target dose coverage. Complexity of the resulting fluence maps was minimized using the sum of positive gradients technique. The results showed XMRT's ability to improve healthy-organ dose reduction while yielding comparable coverage of the target relative to IMRT for all geometries. All three energy-optimization approaches yielded similar HI and CNs for all geometries, as well as a similar degree of fluence map complexity. The dose reduction provided by XMRT was demonstrated by the relative decrease in the dose metrics for the majority of the organs at risk (OARs) in all geometries. Largest reductions ranged between 5% to 10% in the mean dose to OARs for two of the geometries when compared with both single-energy IMRT schemes. XMRT has shown potential dosimetric benefits through improved OAR sparing by allowing beam energy to act as a degree of freedom in the EBRT optimization process.
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Affiliation(s)
- Philip McGeachy
- Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4, Canada. Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB T2N 4N2, Canada
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De Kerf G, Van Gestel D, Mommaerts L, Van den Weyngaert D, Verellen D. Evaluation of the optimal combinations of modulation factor and pitch for Helical TomoTherapy plans made with TomoEdge using Pareto optimal fronts. Radiat Oncol 2015; 10:191. [PMID: 26377574 PMCID: PMC4573943 DOI: 10.1186/s13014-015-0497-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/03/2015] [Indexed: 11/25/2022] Open
Abstract
Background Modulation factor (MF) and pitch have an impact on Helical TomoTherapy (HT) plan quality and HT users mostly use vendor-recommended settings. This study analyses the effect of these two parameters on both plan quality and treatment time for plans made with TomoEdge planning software by using the concept of Pareto optimal fronts. Methods More than 450 plans with different combinations of pitch [0.10–0.50] and MF [1.2–3.0] were produced. These HT plans, with a field width (FW) of 5 cm, were created for five head and neck patients and homogeneity index, conformity index, dose-near-maximum (D2), and dose-near-minimum (D98) were analysed for the planning target volumes, as well as the mean dose and D2 for most critical organs at risk. For every dose metric the median value will be plotted against treatment time. A Pareto-like method is used in the analysis which will show how pitch and MF influence both treatment time and plan quality. Results For small pitches (≤0.20), MF does not influence treatment time. The contrary is true for larger pitches (≥0.25) as lowering MF will both decrease treatment time and plan quality until maximum gantry speed is reached. At this moment, treatment time is saturated and only plan quality will further decrease. Conclusion The Pareto front analysis showed optimal combinations of pitch [0.23–0.45] and MF > 2.0 for a FW of 5 cm. Outside this range, plans will become less optimal. As the vendor-recommended settings fall within this range, the use of these settings is validated.
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Affiliation(s)
- Geert De Kerf
- Department of Radiotherapy, University Radiotherapy Antwerp (URA), Antwerp, Belgium. .,Present address: Department of Radiotherapy, Iridium Cancer Network, GZA Sint-Augustinus, Oosterveldlaan 24, 2610, Wilrijk, Antwerp, Belgium.
| | - Dirk Van Gestel
- Department of Radiotherapy, University Radiotherapy Antwerp (URA), Antwerp, Belgium.,Present address: Department of Radiotherapy, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Lobke Mommaerts
- Department of Radiotherapy, University Radiotherapy Antwerp (URA), Antwerp, Belgium
| | | | - Dirk Verellen
- Radiotherapy UZ Brussel, Faculty of Medicine and Pharmacy Vrije Universiteit Brussel, Brussels, Belgium
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Zhu L, Niu T, Choi K, Xing L. Total-variation regularization based inverse planning for intensity modulated arc therapy. Technol Cancer Res Treat 2015; 11:149-62. [PMID: 22335409 DOI: 10.7785/tcrt.2012.500244] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Intensity modulated arc therapy (IMAT) delivers conformal dose distributions through continuous gantry rotation with constant or variable speed while modulating the field aperture shape and weight. The enlarged angular space and machine delivery constraints make inverse planning of IMAT more intractable as compared to its counterpart of fixed gantry IMRT. Currently, IMAT inverse planning is being done using two extreme methods: the first one computes in beamlet domain with a subsequent arc leaf sequencing, and the second proceeds in machine parameter domain with entire emphasis placed on a pre-determined delivery method without exploring potentially better alternative delivery schemes. Towards truly optimizing the IMAT treatment on a patient specific basis, in this work we propose a total-variation based inverse planning framework for IMAT, which takes advantage of the useful features of the above two existing approaches while avoiding their shortcomings. A quadratic optimization algorithm has been implemented to demonstrate the performance and advantage of the proposed approach. Applications of the technique to a prostate case and a head and neck case indicate that the algorithm is capable of generating IMAT plans with patient specific numbers of arcs efficiently. Superior dose distributions and delivery time are achieved with a maximum number of apertures of three for each field. As compared to conventional beamlet-based algorithms, our method regularizes the field modulation complexity during optimization, and permits us to obtain the best possible plan with a pre-set modulation complexity of fluences. As illustrated in both prostate and head-and-neck case studies, the proposed method produces more favorable dose distributions than the segment-based algorithms, by optimally accommodating the clinical need of intensity modulation levels for each individual field. On a more fundamental level, our formulation preserves the convexity of optimization and makes the search of the global optimal solution possible with a deterministic method.
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Affiliation(s)
- Lei Zhu
- George W. Woodruff School, Nuclear and Radiological Engineering and Medical Physics Programs, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
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Ghandour S, Matzinger O, Pachoud M. Volumetric-modulated arc therapy planning using multicriteria optimization for localized prostate cancer. J Appl Clin Med Phys 2015; 16:5410. [PMID: 26103500 PMCID: PMC5690115 DOI: 10.1120/jacmp.v16i3.5410] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 01/30/2015] [Accepted: 01/23/2015] [Indexed: 11/23/2022] Open
Abstract
The purpose of this work is to evaluate the volumetric‐modulated arc therapy (VMAT) multicriteria optimization (MCO) algorithm clinically available in the RayStation treatment planning system (TPS) and its ability to reduce treatment planning time while providing high dosimetric plan quality. Nine patients with localized prostate cancer who were previously treated with 78 Gy in 39 fractions using VMAT plans and rayArc system based on the direct machine parameter optimization (DMPO) algorithm were selected and replanned using the VMAT‐MCO system. First, the dosimetric quality of the plans was evaluated using multiple conformity metrics that account for target coverage and sparing of healthy tissue, used in our departmental clinical protocols. The conformity and homogeneity index, number of monitor units, and treatment planning time for both modalities were assessed. Next, the effects of the technical plan parameters, such as constraint leaf motion CLM (cm/°) and maximum arc delivery time T (s), on the accuracy of delivered dose were evaluated using quality assurance passing rates (QAs) measured using the Delta4 phantom from ScandiDos. For the dosimetric plan's quality analysis, the results show that the VMAT‐MCO system provides plans comparable to the rayArc system with no statistical difference for V95% (p<0.01), D1% (p<0.01), CI (p<0.01), and HI (p<0.01) of the PTV, bladder (p<0.01), and rectum (p<0.01) constraints, except for the femoral heads and healthy tissues, for which a dose reduction was observed using MCO compared with rayArc (p<0.01). The technical parameter study showed that a combination of CLM equal to 0.5 cm/degree and a maximum delivery time of 72 s allowed the accurate delivery of the VMAT‐MCO plan on the Elekta Versa HD linear accelerator. Planning evaluation and dosimetric measurements showed that VMAT‐MCO can be used clinically with the advantage of enhanced planning process efficiency by reducing the treatment planning time without impairing dosimetric quality. PACS numbers: 87.55.D, 87.55.de, 87.55.Qr
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Affiliation(s)
- Sarah Ghandour
- Cancer Center - Radiotherapy Department, Riviera-Chablais Hospital.
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Craft D, Bangert M, Long T, Papp D, Unkelbach J. Shared data for intensity modulated radiation therapy (IMRT) optimization research: the CORT dataset. Gigascience 2014; 3:37. [PMID: 25678961 PMCID: PMC4326207 DOI: 10.1186/2047-217x-3-37] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 11/19/2014] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND We provide common datasets (which we call the CORT dataset: common optimization for radiation therapy) that researchers can use when developing and contrasting radiation treatment planning optimization algorithms. The datasets allow researchers to make one-to-one comparisons of algorithms in order to solve various instances of the radiation therapy treatment planning problem in intensity modulated radiation therapy (IMRT), including beam angle optimization, volumetric modulated arc therapy and direct aperture optimization. RESULTS We provide datasets for a prostate case, a liver case, a head and neck case, and a standard IMRT phantom. We provide the dose-influence matrix from a variety of beam/couch angle pairs for each dataset. The dose-influence matrix is the main entity needed to perform optimizations: it contains the dose to each patient voxel from each pencil beam. In addition, the original Digital Imaging and Communications in Medicine (DICOM) computed tomography (CT) scan, as well as the DICOM structure file, are provided for each case. CONCLUSIONS Here we present an open dataset - the first of its kind - to the radiation oncology community, which will allow researchers to compare methods for optimizing radiation dose delivery.
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Affiliation(s)
- David Craft
- />Massachusetts General Hospital, Harvard Medical School, 02114 Boston, MA USA
| | - Mark Bangert
- />German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany
| | - Troy Long
- />University of Michigan, 48109 Ann Arbor, Michigan USA
| | - Dávid Papp
- />Massachusetts General Hospital, Harvard Medical School, 02114 Boston, MA USA
| | - Jan Unkelbach
- />Massachusetts General Hospital, Harvard Medical School, 02114 Boston, MA USA
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Waghorn BJ, Shah AP, Rineer JM, Langen KM, Meeks SL. A margin-based analysis of the dosimetric impact of motion on step-and-shoot IMRT lung plans. Radiat Oncol 2014; 9:46. [PMID: 24499602 PMCID: PMC3922402 DOI: 10.1186/1748-717x-9-46] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 02/01/2014] [Indexed: 12/25/2022] Open
Abstract
Purpose Intrafraction motion during step-and-shoot (SNS) IMRT is known to affect the target dosimetry by a combination of dose blurring and interplay effects. These effects are typically managed by adding a margin around the target. A quantitative analysis was performed, assessing the relationship between target motion, margin size, and target dosimetry with the goal of introducing new margin recipes. Methods A computational algorithm was used to calculate 1,174 motion-encoded dose distributions and DVHs within the patient’s CT dataset. Sinusoidal motion tracks were used simulating intrafraction motion for nine lung tumor patients, each with multiple margin sizes. Results D95% decreased by less than 3% when the maximum target displacement beyond the margin experienced motion less than 5 mm in the superior-inferior direction and 15 mm in the anterior-posterior direction. For target displacements greater than this, D95% decreased rapidly. Conclusions Targets moving in excess of 5 mm outside the margin can cause significant changes to the target. D95% decreased by up to 20% with target motion 10 mm outside the margin, with underdosing primarily limited to the target periphery. Multi-fractionated treatments were found to exacerbate target under-coverage. Margins several millimeters smaller than the maximum target displacement provided acceptable motion protection, while also allowing for reduced normal tissue morbidity.
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Affiliation(s)
| | - Amish P Shah
- Department of Radiation Oncology, UF Health Cancer Center at Orlando Health, 1400 South Orange Avenue MP 730, Orlando, Florida 32806, USA.
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Wilkie JR, Matuszak MM, Feng M, Moran JM, Fraass BA. Use of plan quality degradation to evaluate tradeoffs in delivery efficiency and clinical plan metrics arising from IMRT optimizer and sequencer compromises. Med Phys 2014; 40:071708. [PMID: 23822412 DOI: 10.1118/1.4808118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Plan degradation resulting from compromises made to enhance delivery efficiency is an important consideration for intensity modulated radiation therapy (IMRT) treatment plans. IMRT optimization and/or multileaf collimator (MLC) sequencing schemes can be modified to generate more efficient treatment delivery, but the effect those modifications have on plan quality is often difficult to quantify. In this work, the authors present a method for quantitative assessment of overall plan quality degradation due to tradeoffs between delivery efficiency and treatment plan quality, illustrated using comparisons between plans developed allowing different numbers of intensity levels in IMRT optimization and/or MLC sequencing for static segmental MLC IMRT plans. METHODS A plan quality degradation method to evaluate delivery efficiency and plan quality tradeoffs was developed and used to assess planning for 14 prostate and 12 head and neck patients treated with static IMRT. Plan quality was evaluated using a physician's predetermined "quality degradation" factors for relevant clinical plan metrics associated with the plan optimization strategy. Delivery efficiency and plan quality were assessed for a range of optimization and sequencing limitations. The "optimal" (baseline) plan for each case was derived using a clinical cost function with an unlimited number of intensity levels. These plans were sequenced with a clinical MLC leaf sequencer which uses >100 segments, assuring delivered intensities to be within 1% of the optimized intensity pattern. Each patient's optimal plan was also sequenced limiting the number of intensity levels (20, 10, and 5), and then separately optimized with these same numbers of intensity levels. Delivery time was measured for all plans, and direct evaluation of the tradeoffs between delivery time and plan degradation was performed. RESULTS When considering tradeoffs, the optimal number of intensity levels depends on the treatment site and on the stage in the process at which the levels are limited. The cost of improved delivery efficiency, in terms of plan quality degradation, increased as the number of intensity levels in the sequencer or optimizer decreased. The degradation was more substantial for the head and neck cases relative to the prostate cases, particularly when fewer than 20 intensity levels were used. Plan quality degradation was less severe when the number of intensity levels was limited in the optimizer rather than the sequencer. CONCLUSIONS Analysis of plan quality degradation allows for a quantitative assessment of the compromises in clinical plan quality as delivery efficiency is improved, in order to determine the optimal delivery settings. The technique is based on physician-determined quality degradation factors and can be extended to other clinical situations where investigation of various tradeoffs is warranted.
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Affiliation(s)
- Joel R Wilkie
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109, USA
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