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Li J, Wang L, Zhang X, Liu L, Li J, Chan MF, Sui J, Yang R. Machine Learning for Patient-Specific Quality Assurance of VMAT: Prediction and Classification Accuracy. Int J Radiat Oncol Biol Phys 2019; 105:893-902. [PMID: 31377162 DOI: 10.1016/j.ijrobp.2019.07.049] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 07/06/2019] [Accepted: 07/27/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE To assess the accuracy of machine learning to predict and classify quality assurance (QA) results for volumetric modulated arc therapy (VMAT) plans. METHODS AND MATERIALS Three hundred three VMAT plans, including 176 gynecologic cancer and 127 head and neck cancer plans, were chosen in this study. Fifty-four complexity metrics were extracted from the QA plans and considered as inputs. Patient-specific QA was performed, and gamma passing rates (GPRs) were used as outputs. One Poisson lasso (PL) regression model was developed, aiming to predict individual GPR, and 1 random forest (RF) classification model was developed to classify QA results as "pass" or "fail." Both technical validation (TV) and clinical validation (CV) were used to evaluate the model reliability. GPR prediction accuracy of PL and classification performance of PL and RF were evaluated. RESULTS In TV, the mean prediction error of PL was 1.81%, 2.39%, and 4.18% at 3%/3 mm, 3%/2 mm, and 2%/2 mm, respectively. No significant differences in prediction errors between TV and CV were observed. In QA results classification, PL had a higher specificity (accurately identifying plans that can pass QA), whereas RF had a higher sensitivity (accurately identifying plans that may fail QA). By using 90% as the action limit at a 3%/2 mm criterion, the specificity of PL and RF was 97.5% and 87.7% in TV and 100% and 71.4% in CV, respectively. The sensitivity of PL and RF was 31.6% and 100% in TV and 33.3% and 100% in CV, respectively. With 100% sensitivity, the QA workload of 81.2% of plans in TV and 62.5% of plans in CV could be reduced by RF. CONCLUSIONS The PL model could accurately predict GPR for most VMAT plans. The RF model with 100% sensitivity was preferred for QA results classification. Machine learning can be a useful tool to assist VMAT QA and reduce QA workload.
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Affiliation(s)
- Jiaqi Li
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Le Wang
- Brainnetome Center & National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Xile Zhang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Lu Liu
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Jun Li
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China
| | - Maria F Chan
- Medical Physics Department, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jing Sui
- Brainnetome Center & National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China; CAS Center for Excellence in Brain Science and Intelligence Technology, Institute of Automation, Chinese Academy of Sciences, Beijing, China.
| | - Ruijie Yang
- Department of Radiation Oncology, Peking University Third Hospital, Beijing, China.
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Antoine M, Ralite F, Soustiel C, Marsac T, Sargos P, Cugny A, Caron J. Use of metrics to quantify IMRT and VMAT treatment plan complexity: A systematic review and perspectives. Phys Med 2019; 64:98-108. [PMID: 31515041 DOI: 10.1016/j.ejmp.2019.05.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 05/24/2019] [Accepted: 05/26/2019] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Fixed-field intensity modulated radiation therapy (FF-IMRT) or volumetric modulated arc therapy (VMAT) beams complexity is due to fluence fluctuation. Pre-treatment Quality Assurance (PTQA) failure could be linked to it. Several plan complexity metrics (PCM) have been published to quantify this complexity but in a heterogeneous formalism. This review proposes to gather different PCM and to discuss their eventual PTQA failure identifier abilities. METHODS AND MATERIALS A systematic literature search and outcome extraction from MEDLINE/PubMed (National Center for Biotechnology Information, NCBI) was performed. First, a list and a synthesis of available PCM is made in a homogeneous formalism. Second, main results relying on the link between PCM and PTQA results but also on other uses are listed. RESULTS A total of 163 studies were identified and n = 19 were selected after inclusion and exclusion criteria application. Difference is made between fluence and degree of freedom (DOF)-based PCM. Results about the PCM potential as PTQA failure identifier are described and synthesized. Others uses are also found in quality, big data, machine learning and audit procedure. CONCLUSIONS A state of the art is made thanks to this homogeneous PCM classification. For now, PCM should be seen as a planning procedure quality indicator although PTQA failure identifier results are mitigated. However limited clinical use seems possible for some cases. Yet, addressing the general PTQA failure prediction case could be possible with the big data or machine learning help.
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Affiliation(s)
- Mikaël Antoine
- Service d'onco-radiothérapie, Polyclinique de Bordeaux Nord, 33000 Bordeaux, France; Department of Radiotherapy, Institut Bergonié, Comprehensive Cancer Centre, F-33000 Bordeaux, France.
| | - Flavien Ralite
- Department of Radiotherapy, Institut Bergonié, Comprehensive Cancer Centre, F-33000 Bordeaux, France; SUBATECH, IMT-Atlantique, CNRS/IN2P3, Université de Nantes, Nantes, France
| | - Charles Soustiel
- Department of Radiotherapy, Centre Hospitalier de Dax, Dax, France
| | - Thomas Marsac
- Department of Radiotherapy, Institut Bergonié, Comprehensive Cancer Centre, F-33000 Bordeaux, France
| | - Paul Sargos
- Department of Radiotherapy, Institut Bergonié, Comprehensive Cancer Centre, F-33000 Bordeaux, France
| | - Audrey Cugny
- Department of Radiotherapy, Institut Bergonié, Comprehensive Cancer Centre, F-33000 Bordeaux, France
| | - Jérôme Caron
- Department of Radiotherapy, Institut Bergonié, Comprehensive Cancer Centre, F-33000 Bordeaux, France
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Villaggi E, Hernandez V, Fusella M, Moretti E, Russo S, Vaccara EML, Nardiello B, Esposito M, Saez J, Cilla S, Marino C, Stasi M, Mancosu P. Plan quality improvement by DVH sharing and planner's experience: Results of a SBRT multicentric planning study on prostate. Phys Med 2019; 62:73-82. [PMID: 31153401 DOI: 10.1016/j.ejmp.2019.05.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/12/2019] [Accepted: 05/02/2019] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To evaluate, in a multi-institutional context, the role of Dose Volume Histogram (DVH) sharing in order to achieve higher plan quality, to harmonize prostate Stereotactic Body Radiation Therapy (SBRT) plans and to assess if the planner's experience in SBRT could lead to lower dose at organs at risk (OARs). METHODS During the first phase five patients enrolled for prostate SBRT were planned by multiple physicists according to common protocol. The prescription dose was 35 Gy in 5 fractions. Dosimetric parameters, modulation index (MIt), plan parameters, and planner experience level (EL) were statistically analyzed. During the second phase median DVHs from all centers were shared and physicists replanned one patient of the five, aiming at inter-planner harmonization and further OARs sparing. Data were summarized by Spearman-correlogram (p < 0.05) and boxplots. The Kruskal-Wallis test was used to compare the re-plans to the original plans. RESULTS Seventy-eight SBRT plans from 13 centers were evaluated. EL correlated with modulation of plan parameters and reduction of OARs doses, such as volume receiving 28 Gy of rectum (rectum-V28Gy), rectum-V32Gy, and bladder-V30Gy. The re-plans showed significant reduced variability in rectum-V28Gy and increased PTV dose homogeneity. No significant difference in plan complexity metrics and plan parameters between plans and re-plans were obtained. CONCLUSIONS Planner's experience in prostate SBRT was correlated with dosimetric parameters. Sharing median DVHs reduced variability among centers whilst keeping the same level of plan complexity. SBRT planning skills can benefit from a replanning phase after sharing DVHs from multiple centers, improving plan quality and concordance among centers.
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Affiliation(s)
- Elena Villaggi
- Medical Physics Unit, Azienda Unità Sanitaria Locale di Piacenza, Italy.
| | - Victor Hernandez
- Hospital Universitari Sant Joan de Reus, Department of Medical Physics, Tarragona, Spain
| | - Marco Fusella
- Medical Physics Department, Veneto Institute of Oncology IOV-IRCCS, Padova, Italy
| | - Eugenia Moretti
- Department of Medical Physics, Azienda Sanitaria Universitaria Integrata di Udine, Italy
| | - Serenella Russo
- Medical Physics Unit, Azienda USL Toscana Centro, Firenze I-50012, Italy
| | | | | | - Marco Esposito
- Medical Physics Unit, Azienda USL Toscana Centro, Firenze I-50012, Italy
| | - Jordi Saez
- Hospital Clinic de Barcelona, Department of Radiation Oncology, Barcelona, Spain
| | - Savino Cilla
- Medical Physics Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy
| | | | - Michele Stasi
- Department of Medical Physics, Azienda Ospedaliera Ordine Mauriziano di Torino, Turin, Italy
| | - Pietro Mancosu
- Medical Physics Unit of Radiation Oncology Dept., Humanitas Research Hospital, Milano, Italy
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Chun M, Joon An H, Kwon O, Oh DH, Park JM, Kim JI. Impact of plan parameters and modulation indices on patient-specific QA results for standard and stereotactic VMAT. Phys Med 2019; 62:83-94. [PMID: 31153402 DOI: 10.1016/j.ejmp.2019.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/03/2019] [Accepted: 05/04/2019] [Indexed: 12/30/2022] Open
Abstract
PURPOSE To demonstrate the impact of modulation indices and plan parameters on the gamma passing rates (GPR) of patient-specific quality assurance of standard and stereotactic volumetric modulated arc therapy (VMAT) plans. METHODS A total of 758 patients' QA plans were utilized, including standard VMAT plans with Trilogy (n = 87, group A) and TreuBeam STx (n = 332, group B), and 339 stereotactic VMAT plans with TrueBeam STx (group C). Modulation indices were obtained considering the speed and acceleration of the multileaf collimator (MLC) (MIs, MIa), and MLC, gantry speed, and dose rate changes (MIt). The mean aperture size (MA), monitor unit (MU), and amount of jaw tracking (%JT) were acquired. Gamma analysis was performed with 2 mm/2% and 1 mm/2% for the standard and stereotactic VMAT plans, respectively. Statistical analyses were performed to investigate the correlation between modulation index/plan parameters and GPR. RESULTS Spearman's rank correlation to GPRs with MIs, MIa, and MIt, were -0.44, -0.45, and -0.46 for group A; -0.39, -0.37, and -0.38 for group B; and -0.04, -0.11, and -0.10 for group C, respectively. While MU and MA showed significant correlations in all groups, %JT showed a significant correlation only with stereotactic VMAT plans. The most influential parameter combinations were MU-MA (rs = 0.50), MIs-%JT (rs = 0.43), and MU-%JT (rs = 0.38) for groups A, B, and C, respectively. CONCLUSIONS MLC modulation mostly affected the GPR in the delivery of standard VMAT plans, while MU and %JT showed more importance in stereotactic VMAT plans.
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Affiliation(s)
- Minsoo Chun
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Hyun Joon An
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ohyun Kwon
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Do Hoon Oh
- Department of Radiation Oncology, Chung-Ang University Hospital, Seoul, Republic of Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Republic of Korea
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
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Park JM, Kim JI, Park SY. Modulation indices and plan delivery accuracy of volumetric modulated arc therapy. J Appl Clin Med Phys 2019; 20:12-22. [PMID: 31038843 PMCID: PMC6560241 DOI: 10.1002/acm2.12589] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/31/2019] [Accepted: 03/10/2019] [Indexed: 12/25/2022] Open
Abstract
PURPOSE We evaluated the performance of various modulation indices (MI) for volumetric modulated arc therapy (VMAT) to predict plan delivery accuracy. METHODS The specific indices evaluated were MI quantifying the mechanical uncertainty (MIt ), MI quantifying the mechanical and dose calculation uncertainties (MIc ), MI for station parameter optimized radiation therapy (MISPORT ), modulation complexity score for VMAT (MCSv ), leaf travel modulation complexity score (LTMCS), plan averaged beam area (PA), plan averaged beam irregularity (PI), plan averaged beam modulation (PM), and plan normalized monitor unit (PMU) to predict VMAT delivery accuracy. By utilizing 240 VMAT plans generated with the Trilogy and TrueBeam STx, Spearman's rank correlation coefficients (r) were calculated between the MIs and measures of conventional methods. RESULTS For the Trilogy system, MIc showed the highest r values with gamma passing rates (GPRs) (r = -0.624 with P < 0.001 for MapCHECK2 and r = -0.655 with P < 0.001 for ArcCHECK). For TrueBeam STx, MIc also showed the highest r values with GPRs (r = -0.625 with P < 0.001 for the MapCHECK2 and r = -0.561 with P < 0.001 for the ArcCHECK). The MIt and MIc showed the highest r values to the MLC position errors for the Trilogy and TrueBeam STx systems (r = 0.770 with P < 0.001 and r = 0.712 with P < 0.001, respectively). The PA showed the highest percent of r values (P < 0.05) to differences in the dose-volume parameters between original VMAT plans and actual deliveries for the Trilogy systems (30.9%). Both the MIt and MIc showed the highest percent of r values (P < 0.05) to differences in the dose-volume parameters between original VMAT plans and actual deliveries for the TrueBeam STx systems (31.8%). CONCLUSION To comprehensively review the results, the MIc showed the best performance to predict the VMAT delivery accuracy.
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Affiliation(s)
- Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,Institute for Smart System, Robotics Research Laboratory for Extreme Environments, Advanced Institutes of Convergence Technology, Suwon, Korea
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - So-Yeon Park
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,Department of Radiation Oncology, Veterans Health Service Medical Center, Seoul, Korea
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Russo S, Esposito M, Hernandez V, Saez J, Rossi F, Paoletti L, Pini S, Bastiani P, Reggiori G, Nicolini G, Vanetti E, Tomatis S, Scorsetti M, Mancosu P. Does deep inspiration breath hold reduce plan complexity? Multicentric experience of left breast cancer radiotherapy with volumetric modulated arc therapy. Phys Med 2019; 59:79-85. [PMID: 30928069 DOI: 10.1016/j.ejmp.2019.02.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 01/14/2019] [Accepted: 02/20/2019] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Volumetric modulated arc therapy (VMAT) for left breast treatments allows heart sparing without compromising PTV coverage. However, this technique may require highly complex plans. Deep Inspiration Breath Hold (DIBH) procedure increases the heart-to-breast distance, facilitating the dose sparing of the heart. The aim of the present work was to investigate if the cardiac-sparing benefits of the DIBH technique were achieved with lower plan modulation and complexity than Free Breathing (FB) treatments. METHODS AND MATERIALS Ten left side breast cases were considered by two centers with different treatment planning systems (TPS) and Linacs. VMAT plans were elaborated in FB and DIBH according to the same protocol. Plan complexity was evaluated by scoring several complexity indices. A new global score index accounting for both plan quality and dosimetric parameters was defined. Pre-treatment QA was performed for all VMAT plans using EPID and Epiqa software. RESULTS DIBH-VMAT plans were associated with significant PTV coverage improvement and mean heart dose reduction (p < 0.003), increasing the resulting global score index. All the evaluated complexity indices showed lower plan complexity for DIBH plans than FB ones, but only in few cases the results were statistically significant. All plans passed the gamma analysis with the selected criteria. CONCLUSIONS The DIBH technique is superior to the FB technique when the heart needs further sparing, allowing a reduction of the doses to OARs with a slightly lower degree of plan complexity and without compromising plan deliverability. These benefits were achieved regardless of the technological scenarios adopted.
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Affiliation(s)
| | - Marco Esposito
- Medical Physics Unit, AUSL Toscana Centro, Florence, Italy
| | - Victor Hernandez
- Department of Medical Physics, Hospital Universitari Sant Joan de Reus, Tarragona, Spain
| | - Jordi Saez
- Radiation Oncology Department, Hospital Clinic de Barcelona, Barcelona, Spain
| | | | - Lisa Paoletti
- Radiotherapy Unit, AUSL Toscana Centro, Florence, Italy
| | - Silvia Pini
- Medical Physics Unit, AUSL Toscana Centro, Florence, Italy
| | | | - Giacomo Reggiori
- Medical Physicist Group of Radiotherapy and Radiosurgery Dept., Humanitas Clinical and Research Hospital IRCCS, Milan-Rozzano, Italy
| | - Giorgia Nicolini
- Medical Physics Team, Radiqa Developments, Bellinzona, Switzerland
| | - Eugenio Vanetti
- Medical Physics Team, Radiqa Developments, Bellinzona, Switzerland
| | - Stefano Tomatis
- Medical Physicist Group of Radiotherapy and Radiosurgery Dept., Humanitas Clinical and Research Hospital IRCCS, Milan-Rozzano, Italy
| | - Marta Scorsetti
- Radiotherapy and Radiosurgery Dept, Humanitas Clinical and Research Hospital IRCCS, Milan-Rozzano, Italy; Department of Biomedical Sciences, Humanitas University, Milan-Rozzano, Italy
| | - Pietro Mancosu
- Medical Physicist Group of Radiotherapy and Radiosurgery Dept., Humanitas Clinical and Research Hospital IRCCS, Milan-Rozzano, Italy
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Evaluation of the plan delivery accuracy of intensity-modulated radiation therapy by texture analysis using fluence maps. Phys Med 2019; 59:64-74. [DOI: 10.1016/j.ejmp.2019.02.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 02/18/2019] [Accepted: 02/20/2019] [Indexed: 02/07/2023] Open
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Edvardsson A, Scherman J, Nilsson MP, Wennberg B, Nordström F, Ceberg C, Ceberg S. Breathing-motion induced interplay effects for stereotactic body radiotherapy of liver tumours using flattening-filter free volumetric modulated arc therapy. ACTA ACUST UNITED AC 2019; 64:025006. [DOI: 10.1088/1361-6560/aaf5d9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Park SY, Kim JI, Chun M, Ahn H, Park JM. Assessment of the modulation degrees of intensity-modulated radiation therapy plans. Radiat Oncol 2018; 13:244. [PMID: 30545396 PMCID: PMC6293636 DOI: 10.1186/s13014-018-1193-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 11/27/2018] [Indexed: 11/23/2022] Open
Abstract
Background To evaluate the modulation indices (MIs) for predicting the plan delivery accuracies of intensity-modulated radiation therapy (IMRT) plans. Methods A total of 100 dynamic IMRT plans that used TrueBeam STx and 102 dynamic IMRT plans that used Trilogy were selected. For each plan, various MIs were calculated, which included the modulation complexity score (MCS), plan-averaged beam area (PA), plan-averaged beam irregularity (PI), plan-averaged beam modulation (PM), MI quantifying multi-leaf collimator (MLC) speeds (MIs), MI quantifying MLC acceleration (MIa), and MI quantifying MLC acceleration and segment aperture irregularity (MIc,IMRT). To determine plan delivery accuracy, global gamma passing rates, MLC errors of log files, and dose-volumetric parameter differences between original and log file-reconstructed IMRT plans were obtained. To assess the ability of each MI for predicting plan delivery accuracy, Spearman’s rank correlation coefficients (rs) between MIs and plan delivery accuracy measures were calculated. Results PI showed moderately strong correlations with gamma passing rates in MapCHECK2 measurements of both TrueBeam STx and Trilogy (rs = − 0.591 with p < 0.001 and − 0.427 with p < 0.001 to with gamma criterion of 2%/2 mm, respectively). For ArcCHECK measurements, PI also showed moderately strong correlations with the gamma passing rates in the ArcCHECK measurements of TrueBeam STx and Trilogy (rs = − 0.545 with p < 0.001 and rs = − 0.581 with p < 0.001 with gamma criterion of 2%/2 mm, respectively). The PI showed the second strongest correlation with MLC errors in both TrueBeam STx and Trilogy (rs = 0.861 with p < 0.001 and rs = 0.767 with p < 0.001, respectively). In general, the PI showed moderately strong correlations with every plan delivery accuracy measure. Conclusions The PI showed moderately strong correlations with every plan delivery accuracy measure and therefore is a useful predictor of IMRT delivery accuracy. Electronic supplementary material The online version of this article (10.1186/s13014-018-1193-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- So-Yeon Park
- Department of Radiation Oncology, Veterans Health Service Medical Center, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Jung-In Kim
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Minsoo Chun
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyunjun Ahn
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jong Min Park
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Institute for Smart System, Robotics Research Laboratory for Extreme Environments, Advanced Institutes of Convergence Technology, Suwon, Republic of Korea.
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Russo S, Esposito M, Hernandez V, Saez J, Rossi F, Paoletti L, Bastiani P, Tomatis S, Mancosu P. 3. Is DIBH VMAT in left breast related to lower plan complexity than Free Breathing? A multicenter experience. Phys Med 2018. [DOI: 10.1016/j.ejmp.2018.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Glenn MC, Hernandez V, Saez J, Followill DS, Howell RM, Pollard-Larkin JM, Zhou S, Kry SF. Treatment plan complexity does not predict IROC Houston anthropomorphic head and neck phantom performance. Phys Med Biol 2018; 63:205015. [PMID: 30230475 PMCID: PMC6287268 DOI: 10.1088/1361-6560/aae29e] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previous works indicate that intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) plans that are highly complex may produce more errors in dose calculation and treatment delivery. Multiple complexity metrics have been proposed and associated with IMRT QA results, but their relationships with plan performance using in situ dose measurements have not been thoroughly investigated. This study aimed to evaluate the relationships between IMRT treatment plan complexity and anthropomorphic phantom performance in order to assess the extent to which plan complexity is related to dosimetric performance in the IROC phantom credentialing program. Sixteen complexity metrics, including the modulation complexity score (MCS), several modulation indices, and total monitor units (MU) delivered, were evaluated for 343 head and neck phantom irradiations, comprising both IMRT (step-and-shoot and sliding window techniques) and VMAT. Spearman's correlations were used to explore the relationship between complexity and plan performance, as measured by the dosimetric differences between the treatment planning system (TPS) and thermoluminescent dosimeter (TLD) measurement, as well as film gamma analysis. Relationships were likewise determined for several combinations of subpopulations, based on the linear accelerator model, TPS used, and delivery modality. Evaluation of the complexity metrics presented here yielded no significant relationships (p > 0.01, Bonferroni-corrected) and all correlations were weak (less than ±0.30). These results indicate that complexity metrics have limited predictive utility in assessing plan performance in multi-institutional comparisons of IMRT plans. Other factors affecting plan accuracy, such as dosimetric modeling or multileaf collimator (MLC) performance, should be investigated to determine a more probable cause for dose delivery errors.
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Affiliation(s)
- Mallory C. Glenn
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Victor Hernandez
- Department of Medical Physics, Hospital Universitari Sant Joan de Reus, Tarragona, Spain
| | - Jordi Saez
- Department of Radiation Oncology, Hospital Clmic de Barcelona, Barcelona, Spain
| | - David S. Followill
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Rebecca M. Howell
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Julianne M. Pollard-Larkin
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Shouhao Zhou
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Stephen F. Kry
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX 77030
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
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Edvardsson A, Nordström F, Ceberg C, Ceberg S. Motion induced interplay effects for VMAT radiotherapy. ACTA ACUST UNITED AC 2018; 63:085012. [DOI: 10.1088/1361-6560/aab957] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Hernandez V, Saez J, Pasler M, Jurado-Bruggeman D, Jornet N. Comparison of complexity metrics for multi-institutional evaluations of treatment plans in radiotherapy. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2018; 5:37-43. [PMID: 33458367 PMCID: PMC7807588 DOI: 10.1016/j.phro.2018.02.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 11/17/2022]
Abstract
Several complexity metrics were highly correlated and can be considered equivalent. Other metrics produced different results, especially for plans from different TPSs. Different TPSs prioritise modulation of different plan parameters. The ranking of plan complexity can greatly depend on the metric used. This must be carefully considered in multi-institutional plan comparisons.
Background and purpose It is known that intensity-modulated radiotherapy plans that are highly complex might be less accurate in dose calculation and treatment delivery. Multiple complexity metrics have been proposed, but the relationships between them have not been thoroughly investigated. This study investigated these relationships in multi-institutional comparisons of treatment plans, where plans from multiple treatment planning systems (TPSs) are typically evaluated. Materials and methods A program was developed to compute several complexity indices and provide analysis of dynamic plan parameters. This in-house software was used to analyse plans from a recent multi-institutional audit. Additionally, 100 clinical volumetric modulated arc therapy (VMAT) plans from two institutions using different TPSs were analysed. Results All plans produced satisfactory pre-treatment verification results and, hence, complexity metrics could not be used to predict plans failing QA. Regarding the relationship among complexity indices, some very strong correlations were found (r > 0.9 with p < 0.01). However, some relevant discrepancies between complexity indices were obtained, even with negative correlation coefficients (r ∼ −0.6) which were expected to be positive. These discrepancies could be explained because each complexity index focused on different features of the plan and different TPSs prioritised modulation of different plan parameters. Conclusions Some complexity indices provided similar information and can be considered equivalent. However, indices that focused on different plan parameters yielded different results and it was unclear which complexity index should be used. Careful consideration should be given to the use of complexity metrics in multi-institutional studies.
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Affiliation(s)
- Victor Hernandez
- Department of Medical Physics, Hospital Universitari Sant Joan de Reus, IISPV, Tarragona, Spain
| | - Jordi Saez
- Department of Radiation Oncology, Hospital Clínic de Barcelona, Spain
| | - Marlies Pasler
- Lake Constance Radiation Oncology Center Singen-Friedrichshafen, Germany
| | - Diego Jurado-Bruggeman
- Medical Physics and Radiation Protection Department, Institut Català d'Oncologia, Girona, Spain
| | - Nuria Jornet
- Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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Correlation analysis between 2D and quasi-3D gamma evaluations for both intensity-modulated radiation therapy and volumetric modulated arc therapy. Oncotarget 2018; 8:5449-5459. [PMID: 27690300 PMCID: PMC5354922 DOI: 10.18632/oncotarget.12279] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/21/2016] [Indexed: 01/04/2023] Open
Abstract
The aim of this work was to investigate correlations between 2D and quasi-3D gamma passing rates. A total of 20 patients (10 prostate cases and 10 head and neck cases, H&N) were retrospectively selected. For each patient, both intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were generated. For each plan, 2D gamma evaluation with radiochromic films and quasi-3D gamma evaluation with fluence measurements were performed with both 2%/2 mm and 3%/3 mm criteria. Gamma passing rates were grouped together according to delivery techniques and treatment sites. Statistical analyses were performed to examine the correlation between 2D and quasi-3D gamma evaluations. Statistically significant difference was observed between delivery techniques only in the quasi-3D gamma passing rates with 2%/2 mm. Statistically significant differences were observed between treatment sites in the 2D gamma passing rates (differences of less than 8%). No statistically significant correlations were observed between 2D and quasi-3D gamma passing rates except the VMAT group and the group including both IMRT and VMAT with 3%/3 mm (r = 0.564 with p = 0.012 for theVMAT group and r = 0.372 with p = 0.020 for the group including both IMRT and VMAT), however, those were not strong. No strong correlations were observed between 2D and quasi-3D gamma evaluations.
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Jurado-Bruggeman D, Hernández V, Sáez J, Navarro D, Pino F, Martínez T, Alayrach ME, Ailleres N, Melero A, Jornet N. Multi-centre audit of VMAT planning and pre-treatment verification. Radiother Oncol 2017; 124:302-310. [DOI: 10.1016/j.radonc.2017.05.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 11/24/2022]
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Gamma analysis with a gamma criterion of 2%/1 mm for stereotactic ablative radiotherapy delivered with volumetric modulated arc therapy technique: a single institution experience. Oncotarget 2017; 8:76076-76084. [PMID: 29100293 PMCID: PMC5652687 DOI: 10.18632/oncotarget.18530] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 06/02/2017] [Indexed: 01/13/2023] Open
Abstract
To report a single-institution experience of gamma evaluations with 2%/1 mm for stereotactic ablative radiotherapy (SABR) delivered with volumetric modulated arc therapy (VMAT) technique, from January 2014 to January 2016. A total of 168 SABR VMAT plans were analyzed with a gamma criterion of 2%/1 mm, a threshold value of 10%, and a tolerance level of 90%. Of the 168 cases, four cases failed with 2%/1 mm. The average passing rate was 97.0% ± 2.5%. Three of the four failed cases showed passing rates higher than 90%, which was achieved by shifting the measuring device by 1 mm in the left-to-right or anterior-to-posterior directions. One failed case showed a passing rate higher than 90%, which was achieved by changing the threshold value from 10% to 5%, leading to an increase in the number of tested points from 26 to 51. Concerns regarding the high susceptibility of the gamma criterion of 2%/1 mm to setup errors of the measuring device are unnecessary based on our two-year experience, since only four cases failed with the 2%/1 mm from a total of 168 clinical cases. Therefore, the gamma criterion of 2%/1 mm could be successfully applied in the clinic with its high sensitivity to detect errors in VMAT plans.
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Park JM, Park SY, Kim JH, Carlson J, Kim JI. The effect of extremely narrow MLC leaf width on the plan quality of VMAT for prostate cancer. Radiat Oncol 2016; 11:85. [PMID: 27338929 PMCID: PMC4917980 DOI: 10.1186/s13014-016-0664-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 06/21/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To investigate the effect of multi-leaf collimators (MLCs) with leaf width of 1.25 mm on the plan quality of volumetric modulated arc therapy (VMAT) for prostate cancer. METHODS A total of 20 patients with prostate cancer were retrospectively selected. Using a high definition MLC (HD MLC), primary and boost VMAT plans with two full arcs were generated for each patient (original plan). After that, by shifting the isocenter position of the 2nd arc by 1.25 mm in the cranio-caudal direction, we simulated fluences made with MLCs with leaf width of 1.25 mm. After shifting, primary and boost plans were generated for each patient (shifted plan). A sum plan was generated by summation of the primary and boost plan for each patient. Dose-volumetric parameters were calculated and compared. RESULTS Both the homogeneity index (HI) and conformity index (CI) of the shifted plans were better than those of the original plans in primary plans (HI = 0.065 vs. 0.059 with p < 0.001 and CI = 1.056 vs. 1.044 with p = 0.006). Similarly, the shifted plans for the boost target volume showed better homogeneity and conformity than did the original plans (HI = 0.060 vs. 0.053 with p < 0.001 and CI = 1.015 vs. 1.009 with p < 0.001). The target mean dose of the original plans was closer to the prescription dose than that of the shifted plans in the case of sum plans (81.45 Gy vs. 81.12 Gy with p = 0.001). CONCLUSIONS Use of extremely narrow MLCs could increase dose homogeneity and conformity of the target volume for prostate VMAT.
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Affiliation(s)
- Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, South Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea.,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, South Korea.,Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, South Korea
| | - So-Yeon Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, South Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea.,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, South Korea.,Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, South Korea
| | - Jin Ho Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, South Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea.,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - Joel Carlson
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Seoul National University Graduate School of Convergence Science and Technology, Seoul, South Korea
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, South Korea. .,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, South Korea. .,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, South Korea. .,Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, South Korea.
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Carlson JNK, Park JM, Park SY, Park JI, Choi Y, Ye SJ. A machine learning approach to the accurate prediction of multi-leaf collimator positional errors. Phys Med Biol 2016; 61:2514-31. [PMID: 26948678 DOI: 10.1088/0031-9155/61/6/2514] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Discrepancies between planned and delivered movements of multi-leaf collimators (MLCs) are an important source of errors in dose distributions during radiotherapy. In this work we used machine learning techniques to train models to predict these discrepancies, assessed the accuracy of the model predictions, and examined the impact these errors have on quality assurance (QA) procedures and dosimetry. Predictive leaf motion parameters for the models were calculated from the plan files, such as leaf position and velocity, whether the leaf was moving towards or away from the isocenter of the MLC, and many others. Differences in positions between synchronized DICOM-RT planning files and DynaLog files reported during QA delivery were used as a target response for training of the models. The final model is capable of predicting MLC positions during delivery to a high degree of accuracy. For moving MLC leaves, predicted positions were shown to be significantly closer to delivered positions than were planned positions. By incorporating predicted positions into dose calculations in the TPS, increases were shown in gamma passing rates against measured dose distributions recorded during QA delivery. For instance, head and neck plans with 1%/2 mm gamma criteria had an average increase in passing rate of 4.17% (SD = 1.54%). This indicates that the inclusion of predictions during dose calculation leads to a more realistic representation of plan delivery. To assess impact on the patient, dose volumetric histograms (DVH) using delivered positions were calculated for comparison with planned and predicted DVHs. In all cases, predicted dose volumetric parameters were in closer agreement to the delivered parameters than were the planned parameters, particularly for organs at risk on the periphery of the treatment area. By incorporating the predicted positions into the TPS, the treatment planner is given a more realistic view of the dose distribution as it will truly be delivered to the patient.
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Affiliation(s)
- Joel N K Carlson
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea. Biomedical Research Institute, Seoul National University Hospital, Seoul 03080, Korea
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69
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Kim JI, Chung JB, Song JY, Kim SK, Choi Y, Choi CH, Choi WH, Cho B, Kim JS, Kim SJ, Ye SJ. Confidence limits for patient-specific IMRT dose QA: a multi-institutional study in Korea. J Appl Clin Med Phys 2016; 17:62-69. [PMID: 26894332 PMCID: PMC5690221 DOI: 10.1120/jacmp.v17i1.5607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 09/26/2015] [Accepted: 09/23/2015] [Indexed: 11/23/2022] Open
Abstract
This study aims to investigate tolerance levels for patient-specific IMRT dose QA (DQA) using the confidence limits (CL) determined by a multi-institutional study. Eleven institutions participated in the multi-institutional study in Korea. A total of 155 DQA measurements, consisting of point-dose differences (high- and low-dose regions) and gamma passing rates (composite and per-field) for IMRT patients with brain, head and neck (H&N), abdomen, and prostate cancers were examined. The Shapiro-Wilk test was used to evaluate the normality of data grouped by the treatment sites and the DQA methods. The confidence limit coefficients in cases of the normal distribution, and the two-sided Student's t-distribution were applied to determine the confidence limits for the grouped data. The Spearman's test was applied to assess the sensitivity of DQA results within the limited groups. The differences in CLs between the two confidence coefficients based on the normal and t-distributions were negligible for the point-dose data and the gamma passing rates with 3%/3 mm criteria. However, with 2%/2 mm criteria, the difference in CLs were 1.6% and 2.2% for composite and per-field measurements, respectively. This resulted from the large standard deviation and the more sensitive criteria of 2%/2 mm. There was no noticeable correlation among the different QA methods. Our multi-institutional study suggested that the CL was not a suitable metric for defining the tolerance level when the statistics of the sample group did not follow the normality and had a large standard deviation.
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70
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Gamma-index method sensitivity for gauging plan delivery accuracy of volumetric modulated arc therapy. Phys Med 2015; 31:1118-1122. [DOI: 10.1016/j.ejmp.2015.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/17/2015] [Accepted: 08/30/2015] [Indexed: 11/17/2022] Open
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Park SY, Park JM, Kim JI, Kim H, Kim IH, Ye SJ. Textural feature calculated from segmental fluences as a modulation index for VMAT. Phys Med 2015; 31:981-990. [DOI: 10.1016/j.ejmp.2015.07.143] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 07/07/2015] [Accepted: 07/13/2015] [Indexed: 10/23/2022] Open
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McGarry CK, Agnew CE, Hussein M, Tsang Y, McWilliam A, Hounsell AR, Clark CH. The role of complexity metrics in a multi-institutional dosimetry audit of VMAT. Br J Radiol 2015; 89:20150445. [PMID: 26511276 DOI: 10.1259/bjr.20150445] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE To demonstrate the benefit of complexity metrics such as the modulation complexity score (MCS) and monitor units (MUs) in multi-institutional audits of volumetric-modulated arc therapy (VMAT) delivery. METHODS 39 VMAT treatment plans were analysed using MCS and MU. A virtual phantom planning exercise was planned and independently measured using the PTW Octavius(®) phantom and seven29(®) 2D array (PTW-Freiburg GmbH, Freiburg, Germany). MCS and MU were compared with the median gamma index pass rates (2%/2 and 3%/3 mm) and plan quality. The treatment planning systems (TPS) were grouped by VMAT modelling being specifically designed for the linear accelerator manufacturer's own treatment delivery system (Type 1) or independent of vendor for VMAT delivery (Type 2). Differences in plan complexity (MCS and MU) between TPS types were compared. RESULTS For Varian(®) linear accelerators (Varian(®) Medical Systems, Inc., Palo Alto, CA), MCS and MU were significantly correlated with gamma pass rates. Type 2 TPS created poorer quality, more complex plans with significantly higher MUs and MCS than Type 1 TPS. Plan quality was significantly correlated with MU for Type 2 plans. A statistically significant correlation was observed between MU and MCS for all plans (R = -0.84, p < 0.01). CONCLUSION MU and MCS have a role in assessing plan complexity in audits along with plan quality metrics. Plan complexity metrics give some indication of plan deliverability but should be analysed with plan quality. ADVANCES IN KNOWLEDGE Complexity metrics were investigated for a national rotational audit involving 34 institutions and they showed value. The metrics found that more complex plans were created for planning systems which were independent of vendor for VMAT delivery.
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Affiliation(s)
- Conor K McGarry
- 1 Radiotherapy Physics, Belfast Health and Social Care Trust, Belfast, UK.,2 Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Christina E Agnew
- 1 Radiotherapy Physics, Belfast Health and Social Care Trust, Belfast, UK
| | - Mohammad Hussein
- 3 Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK.,4 Department of Physics, University of Surrey, Guildford, UK
| | - Yatman Tsang
- 5 RTTQA Group, Mount Vernon Hospital, Northwood, Middlesex, UK
| | - Alan McWilliam
- 6 Medical Physics and Engineering Department, Christie Hospital NHS Foundation Trust, Manchester, UK
| | - Alan R Hounsell
- 1 Radiotherapy Physics, Belfast Health and Social Care Trust, Belfast, UK.,2 Centre for Cancer Research and Cell Biology, Queen's University Belfast, Belfast, UK
| | - Catharine H Clark
- 3 Department of Medical Physics, Royal Surrey County Hospital NHS Foundation Trust, Guildford, UK.,4 Department of Physics, University of Surrey, Guildford, UK.,7 Radiation Dosimetry Group, National Physical Laboratory, Teddington, Middlesex, UK
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73
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Park JM, Park SY, Kim H. Modulation index for VMAT considering both mechanical and dose calculation uncertainties. Phys Med Biol 2015; 60:7101-25. [PMID: 26317697 DOI: 10.1088/0031-9155/60/18/7101] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aim of this study is to present a modulation index considering both mechanical and dose calculation uncertainties for volumetric modulated arc therapy (VMAT). As a modulation index considering only mechanical uncertainty of VMAT, MIt has been previously suggested. In this study, we developed a weighting factor which represents dose calculation uncertainty based on the aperture shapes of fluence maps at every control point of VMAT plans. In order to calculate the weighting factor, the thinning algorithm of image processing techniques was applied to measure field aperture irregularity. By combining this weighting factor with the previously suggested modulation index, MIt, comprehensive modulation index (MIc) was designed. To evaluate the performance of MIc, gamma passing rates, differences in mechanical parameters between plans and log files and differences in dose-volume parameters between plans and the plans reconstructed from log files were acquired with a total of 52 VMAT plans. Spearman's correlation coefficients (rs) between the values of MIc and measures of VMAT delivery accuracy were calculated. The rs values of MIc (f = 0.5) to global gamma passing rates with 2%/2 mm, 1%/2 mm and 2%/1 mm were -0.728,-0.847 and -0.617, respectively (p < 0.001). Those to local gamma passing rates were -0.765,-0.767 and -0.748, respectively (p < 0.001). The rs values of MIc (f = 0.5) to multi-leaf collimator and gantry angle errors were 0.800 and -0.712, respectively (p < 0.001). The MIc (f = 0.5) showed a total of 20 rs values (p < 0.05) to the differences in dose-volumetric parameters from a total of 35 tested cases. The MIc (f = 0.5) demonstrated considerable power to predict VMAT delivery accuracy showing strong correlations to various measures of VMAT delivery accuracy.
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Affiliation(s)
- Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, 110-744, Korea. Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 110-744, Korea. Biomedical Research Institute, Seoul National University Hospital, Seoul, 110-744, Korea. Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, 443-270, Korea
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Heo T, Ye SJ, Carlson J, Park JM. The effect of beam interruption during VMAT delivery on the delivered dose distribution. Phys Med 2015; 31:297-300. [DOI: 10.1016/j.ejmp.2015.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/13/2015] [Accepted: 01/23/2015] [Indexed: 11/30/2022] Open
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Park SY, Park JM, Sung W, Kim IH, Ye SJ. Texture analysis on the edge-enhanced fluence of VMAT. Radiat Oncol 2015; 10:74. [PMID: 25890104 PMCID: PMC4386104 DOI: 10.1186/s13014-015-0382-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/16/2015] [Indexed: 11/25/2022] Open
Abstract
Background Textural features of edge-enhanced fluence were analysed to quantify modulation degree of volumetric modulated arc therapy (VMAT) plans. Methods Twenty prostate and twenty head and neck VMAT plans were retrospectively selected. Fluences of VMAT plans were generated by integration of monitor units shaped by multi-leaf collimators (MLCs) at each control point. When generating fluences, the values of pixels representing MLC tips were doubled to prevent smearing out of small or irregular fields (edge-enhancement). Six kinds of textural features, including angular second moment, inverse difference moment, contrast, variance, correlation and entropy, were calculated with particular displacement distances (d) of 1, 5 and 10. Plan delivery accuracy was evaluated by gamma-index method, mechanical parameter differences between plan and delivery and differences in dose-volumetric parameters between plan and delivery. Spearman’s correlation coefficients (rs) were calculated between the values of textural features and VMAT delivery accuracy. Results The rs values of contrast (d = 1) with edge-enhancement to global gamma passing rates with 2%/2 mm, 1%/2 mm and 2%/1 mm were 0.546 (p < 0.001), 0.744 (p < 0.001) and 0.487 (p = 0.001), respectively. Those with local 2%/2 mm, 1%/2 mm and 2%/1 mm were 0.588, 0.640 and 0.644, respectively (all with p < 0.001). The rs values of contrast (d = 1) to MLC and gantry angle errors were -0.853 and 0.655, respectively (all with p < 0.001). The contrast (d = 1) showed statistically significant rs values in 11 dose-volumetric parameter differences from a total of 35 cases, and generally showed better correlations to plan delivery accuracy than did previously suggested textural features with non-edge-enhanced fluences, as well as conventional modulation indices. Conclusions Contrast (d = 1) with edge-enhanced fluences could be used as modulation index for VMAT.
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Affiliation(s)
- So-Yeon Park
- Interdiciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Republic of Korea.
| | - Wonmo Sung
- Department of Transdisciplinary Studies, Program in Biomedical Radiation Sciences, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Republic of Korea.
| | - Il Han Kim
- Interdiciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Republic of Korea.
| | - Sung-Joon Ye
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University College of Medicine, Seoul, Republic of Korea. .,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Department of Transdisciplinary Studies, Program in Biomedical Radiation Sciences, Seoul National University Graduate School of Convergence Science and Technology, Seoul, Republic of Korea.
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76
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Park JM, Wu HG, Kim JH, Carlson JNK, Kim K. The effect of MLC speed and acceleration on the plan delivery accuracy of VMAT. Br J Radiol 2015; 88:20140698. [PMID: 25734490 DOI: 10.1259/bjr.20140698] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE To determine a new metric utilizing multileaf collimator (MLC) speeds and accelerations to predict plan delivery accuracy of volumetric modulated arc therapy (VMAT). METHODS To verify VMAT delivery accuracy, gamma evaluations, analysis of mechanical parameter difference between plans and log files, and analysis of changes in dose-volumetric parameters between plans and plans reconstructed with log files were performed with 40 VMAT plans. The average proportion of leaf speeds ranging from l to h cm s(-1) (Sl-h and l-h = 0-0.4, 0.4-0.8, 0.8-1.2, 1.2-1.6 and 1.6-2.0), mean and standard deviation of MLC speeds were calculated for each VMAT plan. The same was carried out for accelerations in centimetre per second squared (Al-h and l-h = 0-4, 4-8, 8-12, 12-16 and 16-20). The correlations of those indicators to plan delivery accuracy were analysed with Spearman's correlation coefficient (rs). RESULTS The S1.2-1.6 and mean acceleration of MLCs showed generally higher correlations to plan delivery accuracy than did others. The highest rs values were observed between S1.2-1.6 and global 1%/2 mm (rs = -0.698 with p < 0.001) as well as mean acceleration and global 1%/2 mm (rs = -0.650 with p < 0.001). As the proportion of MLC speeds and accelerations >0.4 and 4 cm s(-2) increased, the plan delivery accuracy of VMAT decreased. CONCLUSION The variations in MLC speeds and accelerations showed considerable correlations to VMAT delivery accuracy. ADVANCES IN KNOWLEDGE As the MLC speeds and accelerations increased, VMAT delivery accuracy reduced.
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Affiliation(s)
- J M Park
- 1 Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea
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