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Zeng Y, Li H, Chang Y, Han Y, Liu H, Pang B, Han J, Hu B, Cheng J, Zhang S, Yang K, Quan H, Yang Z. In vivo EPID-based daily treatment error identification for volumetric-modulated arc therapy in head and neck cancers with a hierarchical convolutional neural network: a feasibility study. Phys Eng Sci Med 2024; 47:907-917. [PMID: 38647634 DOI: 10.1007/s13246-024-01414-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Accepted: 03/06/2024] [Indexed: 04/25/2024]
Abstract
We proposed a deep learning approach to classify various error types in daily VMAT treatment of head and neck cancer patients based on EPID dosimetry, which could provide additional information to support clinical decisions for adaptive planning. 146 arcs from 42 head and neck patients were analyzed. Anatomical changes and setup errors were simulated in 17,820 EPID images of 99 arcs obtained from 30 patients using in-house software for model training, validation, and testing. Subsequently, 141 clinical EPID images from 47 arcs belonging to the remaining 12 patients were utilized for clinical testing. The hierarchical convolutional neural network (HCNN) model was trained to classify error types and magnitudes using EPID dose difference maps. Gamma analysis with 3%/2 mm (dose difference/distance to agreement) criteria was also performed. The F1 score, a combination of precision and recall, was utilized to evaluate the performance of the HCNN model and gamma analysis. The adaptive fractioned doses were calculated to verify the HCNN classification results. For error type identification, the overall F1 score of the HCNN model was 0.99 and 0.91 for primary type and subtype identification, respectively. For error magnitude identification, the overall F1 score in the simulation dataset was 0.96 and 0.70 for the HCNN model and gamma analysis, respectively; while the overall F1 score in the clinical dataset was 0.79 and 0.20 for the HCNN model and gamma analysis, respectively. The HCNN model-based EPID dosimetry can identify changes in patient transmission doses and distinguish the treatment error category, which could potentially provide information for head and neck cancer treatment adaption.
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Affiliation(s)
- Yiling Zeng
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, 430072, China
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Heng Li
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Yu Chang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yang Han
- College of Electrical Engineering, Sichuan University, Chengdu, 610065, China
| | - Hongyuan Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Bo Pang
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Jun Han
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Bin Hu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Junping Cheng
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Sheng Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Kunyu Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Hong Quan
- Department of Medical Physics, School of Physics and Technology, Wuhan University, Wuhan, 430072, China.
| | - Zhiyong Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Haghparast M, Parwaie W, Bakhshandeh M, Tuncel N, Rabi Mahdavi S. Evaluation of Perkin Elmer Amorphous Silicon Electronic Portal Imaging Device for Small Photon Field Dosimetry. J Biomed Phys Eng 2024; 14:347-356. [PMID: 39175562 PMCID: PMC11336047 DOI: 10.31661/jbpe.v0i0.2112-1445] [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: 12/26/2021] [Accepted: 01/29/2022] [Indexed: 08/24/2024]
Abstract
Background Electronic portal imaging devices (EPIDs) are applied to measure the dose and verify patients' position. Objective The present study aims to evaluate the performance of EPID for measuring dosimetric parameters in small photon fields. Material and Methods In this experimental study, the output factors and beam profiles were obtained using the amorphous silicon (a-Si) EPID for square field sizes ranging from 1×1 to 10×10 cm2 at energies 6 and 18 mega-voltage (MV). For comparison, the dosimetric parameters were measured with the pinpoint, diode, and Semiflex dosimeters. Additionally, the Monaco treatment planning system was selected to calculate the output factors and beam profiles. Results There was a significant difference between the output factors measured using the EPID and that measured with the other dosimeters for field sizes lower than 8×8 cm2. In the energy of 6 MV, the gamma passing rates (3%/3 mm) between EPID and diode profile were 98%, 98%, 95%, 94%, 93%, and 94% for 1×1, 2×2, 3×3, 4×4, 5×5, and 10×10 cm2, respectively. The measured penumbra width with EPID was higher compared to that measured by the diode dosimeter for both energies. Conclusion The EPID can measure the dosimetric parameters in small photon fields, especially for beam profiles and penumbra measurements.
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Affiliation(s)
- Mohammad Haghparast
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
- Department of Radiology, Faculty of Para-Medicine, Hormozgan University of Medical Sciences, Bandare-Abbas, Iran
| | - Wrya Parwaie
- Department of Medical Physics, Faculty of Paramedical Sciences, Ilam University of Medical Sciences, Ilam, Iran
| | - Mohsen Bakhshandeh
- Department of Radiology Technology, School of Allied Medical Sciences, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Nina Tuncel
- Radiation Oncology Department, School of Medicine, Akdeniz University, Antalya, Turkey
| | - Seied Rabi Mahdavi
- Department of Medical Physics, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
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Kirby J, Chester K. Automation to facilitate optimisation of breast radiotherapy treatments using EPID-based in vivodosimetry. Phys Med Biol 2024; 69:095018. [PMID: 38537296 DOI: 10.1088/1361-6560/ad387e] [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: 11/24/2023] [Accepted: 03/26/2024] [Indexed: 04/25/2024]
Abstract
Objective. To use automation to facilitate the monitoring of each treatment fraction using an electronic portal imaging device (EPID) basedin vivodosimetry (IVD) system, allowing optimisation of breast radiotherapy delivery for individual patients and cohorts.Approach. A suite of in-house software was developed to reduce the number of manual interactions with the commercial IVD system, dosimetry check. An EPID specific pixel sensitivity map facilitated use of the EPID panel away from the central axis. Point dose difference and the change in standard deviation in dose were identified as useful dose metrics, with standard deviation used in preference to gamma in the presence of a systematic dose offset. Automated IVD was completed for 3261 fractions across 704 patients receiving breast radiotherapy.Main results. Multiple opportunities for treatment optimisation were identified for individual patients and across patient cohorts as a result of successful implementation of automated IVD. 5.1% of analysed fractions were out of tolerance with 27.1% of these considered true positives. True positive results were obtained on any fraction of treatment and if IVD had only been completed on the first fraction, 84.4% of true positive results would have been missed. This was made possible due to the automation that saved over 800 h of manual intervention and stored data in an accessible database.Significance. An improved EPID calibration to allow off-axis measurement maximises the number of patients eligible for IVD (36.8% of patients in this study). We also demonstrate the importance in selecting context-specific assessment metrics and how these can lead to a managable false positive rate. We have shown that the use of fully automated IVD facilitates use on every fraction of treatment. This leads to identification of areas for treatment improvement for both individuals and across a patient cohort, expanding the uses of IVD from simply gross error detection towards treatment optimisation.
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Affiliation(s)
- Joshua Kirby
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Freeman Hospital, United Kingdom
| | - Katherine Chester
- Northern Centre for Cancer Care, Newcastle upon Tyne Hospitals NHS Foundation Trust, Cumberland Infirmary, United Kingdom
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Esposito M, Mancosu P, Bruschi A, Ghirelli A, Pini S, Alpi P, Barca R, Paoli CD, Meacci F, Leonulli BG, Fondelli S, Paoletti L, Scoccianti S, Russo S. The role of EPID in vivo dosimetry in the risk management of stereotactic lung treatments. Strahlenther Onkol 2023; 199:992-999. [PMID: 37256302 DOI: 10.1007/s00066-023-02081-x] [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: 09/30/2022] [Accepted: 03/26/2023] [Indexed: 06/01/2023]
Abstract
BACKGROUND AND OBJECTIVE In this work we report our experience with the use of in vivo dosimetry (IVD) in the risk management of stereotactic lung treatments. METHODS A commercial software based on the electronic portal imaging device (EPID) signal was used to reconstruct the actual planning target volume (PTV) dose of stereotactic lung treatments. The study was designed in two phases: i) in the observational phase, the IVD results of 41 consecutive patients were reviewed and out-of-tolerance cases were studied for root cause analysis; ii) in the active phase, the IVD results of 52 patients were analyzed and corrective actions were taken when needed. Moreover, proactive preventions were further introduced to reduce the risk of future failures. The error occurrence rate was analyzed to evaluate the effectiveness of proactive actions. RESULTS A total of 330 fractions were analyzed. In the first phase, 13 errors were identified. In the active phase, 12 errors were detected, 5 of which needed corrective actions; in 4 patients the actions taken corrected the error. Several preventions and barriers were introduced to reduce the risk of future failures: the planning checklist was updated, the procedure for vacuum pillows was improved, and use of the respiratory compression belt was optimized. A decrease in the failure rate was observed, showing the effectiveness of procedural adjustment. CONCLUSION The use of IVD allowed the quality of lung stereotactic body radiation therapy (SBRT) treatments to be improved. Patient-specific and procedural corrective actions were successfully taken as part of risk management, leading to an overall improvement in the dosimetric accuracy.
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Affiliation(s)
- Marco Esposito
- S. C. Fisica Sanitaria, Firenze-Azienda Sanitaria USL Toscana Centro, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy.
- International Center for Theoretical Physics, Strada Costiera, 11, 34151, Trieste, Italy.
| | - Pietro Mancosu
- Medical Physics Unit of Radiotherapy Dept., IRCCS Humanitas Research Hospital, Rozzano, Italy
| | - Andrea Bruschi
- S. C. Fisica Sanitaria, Firenze-Azienda Sanitaria USL Toscana Centro, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy
| | - Alessandro Ghirelli
- S. C. Fisica Sanitaria, Firenze-Azienda Sanitaria USL Toscana Centro, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy
| | - Silvia Pini
- S. C. Fisica Sanitaria, Firenze-Azienda Sanitaria USL Toscana Centro, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy
| | - Paolo Alpi
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | - Raffaella Barca
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | - Camilla Delli Paoli
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | - Fiammetta Meacci
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | | | - Simona Fondelli
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | - Lisa Paoletti
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | - Silvia Scoccianti
- S. C. Radioterapia, Firenze-Azienda Sanitaria USL Toscana Centro, Firenze, Italy
| | - Serenella Russo
- S. C. Fisica Sanitaria, Firenze-Azienda Sanitaria USL Toscana Centro, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy
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Martins JC, Maier J, Gianoli C, Neppl S, Dedes G, Alhazmi A, Veloza S, Reiner M, Belka C, Kachelrieß M, Parodi K. Towards real-time EPID-based 3D in vivo dosimetry for IMRT with Deep Neural Networks: A feasibility study. Phys Med 2023; 114:103148. [PMID: 37801811 DOI: 10.1016/j.ejmp.2023.103148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 08/17/2023] [Accepted: 09/22/2023] [Indexed: 10/08/2023] Open
Abstract
We investigate the potential of the Deep Dose Estimate (DDE) neural network to predict 3D dose distributions inside patients with Monte Carlo (MC) accuracy, based on transmitted EPID signals and patient CTs. The network was trained using as input patient CTs and first-order dose approximations (FOD). Accurate dose distributions (ADD) simulated with MC were given as training targets. 83 pelvic CTs were used to simulate ADDs and respective EPID signals for subfields of prostate IMRT plans (gantry at 0∘). FODs were produced as backprojections from the EPID signals. 581 ADD-FOD sets were produced and divided into training and test sets. An additional dataset simulated with gantry at 90∘ (lateral set) was used for evaluating the performance of the DDE at different beam directions. The quality of the FODs and DDE-predicted dose distributions (DDEP) with respect to ADDs, from the test and lateral sets, was evaluated with gamma analysis (3%,2 mm). The passing rates between FODs and ADDs were as low as 46%, while for DDEPs the passing rates were above 97% for the test set. Meaningful improvements were also observed for the lateral set. The high passing rates for DDEPs indicate that the DDE is able to convert FODs into ADDs. Moreover, the trained DDE predicts the dose inside a patient CT within 0.6 s/subfield (GPU), in contrast to 14 h needed for MC (CPU-cluster). 3D in vivo dose distributions due to clinical patient irradiation can be obtained within seconds, with MC-like accuracy, potentially paving the way towards real-time EPID-based in vivo dosimetry.
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Affiliation(s)
- Juliana Cristina Martins
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. München, 85748, Germany.
| | - Joscha Maier
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany.
| | - Chiara Gianoli
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. München, 85748, Germany.
| | - Sebastian Neppl
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, Munich, 81377, Germany.
| | - George Dedes
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. München, 85748, Germany.
| | - Abdulaziz Alhazmi
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. München, 85748, Germany.
| | - Stella Veloza
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. München, 85748, Germany.
| | - Michael Reiner
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, Munich, 81377, Germany.
| | - Claus Belka
- Department of Radiation Oncology, University Hospital, LMU Munich, Marchioninistraße 15, Munich, 81377, Germany.
| | - Marc Kachelrieß
- German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, 69120, Germany; Heidelberg University, Grabengasse 1, Heidelberg, 69117, Germany.
| | - Katia Parodi
- Department of Medical Physics, Faculty of Physics, Ludwig-Maximilians-Universität München, Am Coulombwall 1, Garching b. München, 85748, Germany.
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Stevens S, Moloney S, Blackmore A, Hart C, Rixham P, Bangiri A, Pooler A, Doolan P. IPEM topical report: guidance for the clinical implementation of online treatment monitoring solutions for IMRT/VMAT. Phys Med Biol 2023; 68:18TR02. [PMID: 37531959 DOI: 10.1088/1361-6560/acecd0] [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: 03/24/2023] [Accepted: 08/02/2023] [Indexed: 08/04/2023]
Abstract
This report provides guidance for the implementation of online treatment monitoring (OTM) solutions in radiotherapy (RT), with a focus on modulated treatments. Support is provided covering the implementation process, from identification of an OTM solution to local implementation strategy. Guidance has been developed by a RT special interest group (RTSIG) working party (WP) on behalf of the Institute of Physics and Engineering in Medicine (IPEM). Recommendations within the report are derived from the experience of the WP members (in consultation with manufacturers, vendors and user groups), existing guidance or legislation and a UK survey conducted in 2020 (Stevenset al2021). OTM is an inclusive term representing any system capable of providing a direct or inferred measurement of the delivered dose to a RT patient. Information on each type of OTM is provided but, commensurate with UK demand, guidance is largely influenced byin vivodosimetry methods utilising the electronic portal imager device (EPID). Sections are included on the choice of OTM solutions, acceptance and commissioning methods with recommendations on routine quality control, analytical methods and tolerance setting, clinical introduction and staffing/resource requirements. The guidance aims to give a practical solution to sensitivity and specificity testing. Functionality is provided for the user to introduce known errors into treatment plans for local testing. Receiver operating characteristic analysis is discussed as a tool to performance assess OTM systems. OTM solutions can help verify the correct delivery of radiotherapy treatment. Furthermore, modern systems are increasingly capable of providing clinical decision-making information which can impact the course of a patient's treatment. However, technical limitations persist. It is not within the scope of this guidance to critique each available solution, but the user is encouraged to carefully consider workflow and engage with manufacturers in resolving compatibility issues.
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Affiliation(s)
| | - Stephen Moloney
- University Hospitals Dorset NHS Foundation Trust, Poole, United Kingdom
| | | | - Clare Hart
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom
| | - Philip Rixham
- Leeds Cancer Centre, Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom
| | - Anna Bangiri
- Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Alistair Pooler
- Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, United Kingdom
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Dogan N, Mijnheer BJ, Padgett K, Nalichowski A, Wu C, Nyflot MJ, Olch AJ, Papanikolaou N, Shi J, Holmes SM, Moran J, Greer PB. AAPM Task Group Report 307: Use of EPIDs for Patient-Specific IMRT and VMAT QA. Med Phys 2023; 50:e865-e903. [PMID: 37384416 PMCID: PMC11230298 DOI: 10.1002/mp.16536] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 04/23/2023] [Accepted: 05/15/2023] [Indexed: 07/01/2023] Open
Abstract
PURPOSE Electronic portal imaging devices (EPIDs) have been widely utilized for patient-specific quality assurance (PSQA) and their use for transit dosimetry applications is emerging. Yet there are no specific guidelines on the potential uses, limitations, and correct utilization of EPIDs for these purposes. The American Association of Physicists in Medicine (AAPM) Task Group 307 (TG-307) provides a comprehensive review of the physics, modeling, algorithms and clinical experience with EPID-based pre-treatment and transit dosimetry techniques. This review also includes the limitations and challenges in the clinical implementation of EPIDs, including recommendations for commissioning, calibration and validation, routine QA, tolerance levels for gamma analysis and risk-based analysis. METHODS Characteristics of the currently available EPID systems and EPID-based PSQA techniques are reviewed. The details of the physics, modeling, and algorithms for both pre-treatment and transit dosimetry methods are discussed, including clinical experience with different EPID dosimetry systems. Commissioning, calibration, and validation, tolerance levels and recommended tests, are reviewed, and analyzed. Risk-based analysis for EPID dosimetry is also addressed. RESULTS Clinical experience, commissioning methods and tolerances for EPID-based PSQA system are described for pre-treatment and transit dosimetry applications. The sensitivity, specificity, and clinical results for EPID dosimetry techniques are presented as well as examples of patient-related and machine-related error detection by these dosimetry solutions. Limitations and challenges in clinical implementation of EPIDs for dosimetric purposes are discussed and acceptance and rejection criteria are outlined. Potential causes of and evaluations of pre-treatment and transit dosimetry failures are discussed. Guidelines and recommendations developed in this report are based on the extensive published data on EPID QA along with the clinical experience of the TG-307 members. CONCLUSION TG-307 focused on the commercially available EPID-based dosimetric tools and provides guidance for medical physicists in the clinical implementation of EPID-based patient-specific pre-treatment and transit dosimetry QA solutions including intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) treatments.
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Affiliation(s)
- Nesrin Dogan
- Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Ben J Mijnheer
- Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Kyle Padgett
- Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Adrian Nalichowski
- Department of Radiation Oncology, Karmanos Cancer Institute, Detroit, Michigan, USA
| | - Chuan Wu
- Department of Radiation Oncology, Sutter Medical Foundation, Roseville, California, USA
| | - Matthew J Nyflot
- Department of Radiation Oncology, University of Washington, Seattle, Washington, USA
| | - Arthur J Olch
- Department of Radiation Oncology, University of Southern California, and Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Niko Papanikolaou
- Division of Medical Physics, UT Health-MD Anderson, San Antonio, Texas, USA
| | - Jie Shi
- Sun Nuclear Corporation - A Mirion Medical Company, Melbourne, Florida, USA
| | | | - Jean Moran
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Peter B Greer
- Department of Radiation Oncology, Calvary Mater Newcastle Hospital, Newcastle, NSW, Australia
- School of Information and Physical Sciences, University of Newcastle, Newcastle, NSW, Australia
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A C Fiagan Y, Bossuyt E, Nevens D, Machiels M, Chiairi I, Joye I, Paul M, Gevaert T, Verellen D. The use of in-vivo dosimetry to identify head and neck cancer patients needing adaptive radiotherapy. Radiother Oncol 2023; 184:109676. [PMID: 37084887 DOI: 10.1016/j.radonc.2023.109676] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 04/12/2023] [Accepted: 04/12/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND AND PURPOSE Head and neck cancer (HNC) patients experiencing anatomical changes during their radiotherapy (RT) course may benefit from adaptive RT (ART). We investigated the sensitivity of an electronic portal imaging device (EPID)-based in-vivo dosimetry (EIVD) systemto detect patients that require ART and identified its limitations. MATERIALS AND METHODS A retrospective study was conducted for 182 HNC patients: laryngeal cancer without elective lymph nodes (group A), postoperative RT (group B) and primary RT including elective lymph nodes (group C). The effect of anatomical changes on the dose distribution and volumetric changes was quantified. The receiver operating characteristic curve was used to obtain the optimal cut-off value for the gamma passing rate (%GP) with a dose difference of 3% and a distance to agreement of 3mm. RESULTS Fifty HNC patients receiving ART were analyzed: 1 in group A, 10 in group B and 39 in group C. Failed fractions (FFs) occurred in 1/1, 6/10 and 23/39 cases before ART in group A, B and C respectively. In the four cases in group B without FFs, only minor dosimetric changes were observed. One of the cases in group C without FFs had significant dosimetric changes (false negative). Three cases received ART because of clinical reasons that cannot be detected by EIVD. The optimal cut-off value for the %GP was 95%/95.2% for old/new generation machines respectively. CONCLUSION EIVD in combined with 3D imaging techniques can be synergistic in the detection of anatomical changes in HNC patients who benefit from ART.
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Affiliation(s)
- Yawo A C Fiagan
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium.
| | - Evy Bossuyt
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium
| | - Daan Nevens
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Melanie Machiels
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Ibrahim Chiairi
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Ines Joye
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Meijnders Paul
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
| | - Thierry Gevaert
- Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium; Department of Radiation Oncology, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium
| | - Dirk Verellen
- Iridium Netwerk, Radiation Oncology, Antwerp, Belgium; Faculty of Medicine and Health Sciences, Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), Universiteit Antwerpen, Antwerp, Belgium
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Mao SPH, Han-Oh S, Moore J, Huang E, McNutt TR, Souranis AN, Briner V, Halthore A, Alcorn SR, Meyer JJ, Viswanathan AN, Wright JL. Selective de-implementation of routine in vivo dosimetry. J Appl Clin Med Phys 2023:e13953. [PMID: 36877712 DOI: 10.1002/acm2.13953] [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: 08/04/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 03/07/2023] Open
Abstract
As cone-beam computed tomography (CBCT) has become the localization method for a majority of cases, the indications for diode-based confirmation of accurate patient set-up and treatment are now limited and must be balanced between proper resource allocation and optimizing efficiency without compromising safety. We undertook a de-implementation quality improvement project to discontinue routine diode use in non-intensity modulated radiotherapy (IMRT) cases in favor of tailored selection of scenarios where diodes may be useful. After analysis of safety reports from the last 5 years, literature review, and stakeholder discussions, our safety and quality (SAQ) committee introduced a recommendation to limit diode use to specific scenarios in which in vivo verification may add value to standard quality assurance (QA) processes. To assess changes in patterns of use, we reviewed diode use by clinical indication 4 months prior and after the implementation of the revised policy, which includes use of diodes for: 3D conformal photon fields set up without CBCT; total body irradiation (TBI); electron beams; cardiac devices within 10 cm of the treatment field; and unique scenarios on a case-by-case basis. We identified 4459 prescriptions and 1038 unique instances of diode use across five clinical sites from 5/2021 to 1/2022. After implementation of the revised policy, we observed an overall decrease in diode use from 32% to 13.2%, with a precipitous drop in 3D cases utilizing CBCT (from 23.2% to 4%), while maintaining diode utilization in the 5 selected scenarios including 100% of TBI and electron cases. By identifying specific indications for diode use and creating a user-friendly platform for case selection, we have successfully de-implemented routine diode use in favor of a selective process that identifies cases where the diode is important for patient safety. In doing so, we have streamlined patient care and decreased cost without compromising patient safety.
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Affiliation(s)
- Serena P H Mao
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Sarah Han-Oh
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Joseph Moore
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Ellen Huang
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Todd R McNutt
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Annette N Souranis
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Valerie Briner
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Aditya Halthore
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Sarah R Alcorn
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Jeffrey J Meyer
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Akila N Viswanathan
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
| | - Jean L Wright
- Department of Radiation Oncology and Molecular Radiation Sciences, The Johns Hopkins University School of Medicine, Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
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10
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Bosco LD, Franceries X, Romain B, Smekens F, Husson F, Le Lann MV. A convolutional neural network model for EPID-based non-transit dosimetry. J Appl Clin Med Phys 2023. [PMID: 36864758 DOI: 10.1002/acm2.13923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
PURPOSE To develop an alternative computational approach for EPID-based non-transit dosimetry using a convolutional neural network model. METHOD A U-net followed by a non-trainable layer named True Dose Modulation recovering the spatialized information was developed. The model was trained on 186 Intensity-Modulated Radiation Therapy Step & Shot beams from 36 treatment plans of different tumor locations to convert grayscale portal images into planar absolute dose distributions. Input data were acquired from an amorphous-Silicon Electronic Portal Image Device and a 6 MV X-ray beam. Ground truths were computed from a conventional kernel-based dose algorithm. The model was trained by a two-step learning process and validated through a five-fold cross-validation procedure with sets of training and validation of 80% and 20%, respectively. A study regarding the dependance of the amount of training data was conducted. The performance of the model was evaluated from a quantitative analysis based the ϒ-index, absolute and relative errors computed between the inferred dose distributions and ground truths for six square and 29 clinical beams from seven treatment plans. These results were also compared to those of an existing portal image-to-dose conversion algorithm. RESULTS For the clinical beams, averages of ϒ-index and ϒ-passing rate (2%-2mm > 10% Dmax ) of 0.24 (±0.04) and 99.29 (±0.70)% were obtained. For the same metrics and criteria, averages of 0.31 (±0.16) and 98.83 (±2.40)% were obtained with the six square beams. Overall, the developed model performed better than the existing analytical method. The study also showed that sufficient model accuracy can be achieved with the amount of training samples used. CONCLUSION A deep learning-based model was developed to convert portal images into absolute dose distributions. The accuracy obtained shows that this method has great potential for EPID-based non-transit dosimetry.
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Affiliation(s)
- Lucas Dal Bosco
- Laboratoire d'Analyse et d'Architecture des Systèmes (LAAS), Toulouse, France
| | - Xavier Franceries
- Institut National de la Santé Et de la Recherche Médicale (INSERM), Toulouse, France
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11
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Bossuyt E, Nevens D, Weytjens R, Taieb Mokaddem A, Verellen D. Assessing the impact of adaptations to the clinical workflow in radiotherapy using transit in vivo dosimetry. Phys Imaging Radiat Oncol 2023; 25:100420. [PMID: 36820237 PMCID: PMC9937948 DOI: 10.1016/j.phro.2023.100420] [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: 10/24/2022] [Revised: 01/26/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Background and Purpose Currently in-vivo dosimetry (IVD) is primarily used to identify individual patient errors in radiotherapy. This study investigated possible correlations of observed trends in transit IVD results, with adaptations to the clinical workflow, aiming to demonstrate the possibility of using the bulk data for continuous quality improvement. Materials and methods In total 84,100 transit IVD measurements were analyzed of all patients treated between 2018 and 2022, divided into four yearly periods. Failed measurements (FM) were divided per pathology and into four categories of causes of failure: technical, planning and positioning problems, and anatomic changes. Results The number of FM due to patient related problems gradually decreased from 9.5% to 6.6%, 6.1% and 5.6% over the study period. FM attributed to positioning problems decreased from 10.0% to 4.9% in boost breast cancer patients after introduction of extra imaging, from 9.1% to 3.9% in Head&Neck patients following education of radiation therapists on positioning of patients' shoulders, from 6.1% to 2.8% in breast cancer patients after introduction of ultrahypofractionated breast radiotherapy with daily online pre-treatment imaging and from 11.2% to 4.3% in extremities following introduction of immobilization with calculated couch parameters and a Surface Guided Radiation Therapy solution. FM related to anatomic changes decreased from 10.2% to 4.0% in rectum patients and from 6.7% to 3.3% in prostate patients following more patient education from dieticians. Conclusions Our study suggests that IVD can be a powerful tool to assess the impact of adaptations to the clinical workflow and its use for continuous quality improvement.
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Affiliation(s)
- Evy Bossuyt
- Iridium Netwerk, GZA Hospitals, Radiation Oncology Department, Antwerp, Belgium,Corresponding author.
| | - Daan Nevens
- Iridium Netwerk, GZA Hospitals, Radiation Oncology Department, Antwerp, Belgium,Faculty of Medicine and Health Sciences, Antwerp University, Antwerp, Belgium
| | - Reinhilde Weytjens
- Iridium Netwerk, GZA Hospitals, Radiation Oncology Department, Antwerp, Belgium
| | | | - Dirk Verellen
- Iridium Netwerk, GZA Hospitals, Radiation Oncology Department, Antwerp, Belgium,Faculty of Medicine and Health Sciences, Antwerp University, Antwerp, Belgium
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12
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Characterization of a commercial EPID-based in-vivo dosimetry and its feasibility and implementation for treatment verification in Malaysia. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2022. [DOI: 10.2478/pjmpe-2022-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Abstract
Introduction: In vivo dosimetry verification is currently a necessity in radiotherapy centres in Europe countries as one of the tools for patient-specific QA, and now its demand is currently rising in developed countries, such as Malaysia. The aim of this study is to characterize commercial EPID-based dosimetry and its implementation for radiotherapy treatment verification in Malaysia.
Materials and Methods: In this work, the sensitivity and performance of a commercially available in vivo dosimetry system, EPIgray® (DOSIsoft, Cachan, France), were qualitatively evaluated prior to its use at our centre. EPIgray response to dose linearity, field size, off-axis, position, and angle dependency tests were performed against TPS calculated dose for 6 MV and 10 MV photon beams. Relative deviations of the total dose were evaluated at isocentre and different depths in the water. EPIgray measured dose was validated by using IMRT and VMAT prostate plan. All calculation points were at the beam isocentre and at points suggested by TG-119 with accepted tolerance of ±10% dose threshold.
Results: EPIgray reported good agreement for linearity, field size, off-axis, and position dependency with TPS dose, being within 5% tolerance for both energy ranges. The average deviation was less than ±2% and ±7% in 6 MV and 10 MV photon beams, respectively, for the angle dependency test. A clinical evaluation performed for the IMRT prostate plan gave average agreement within ±3% at the plan isocentre for both energies. While for the VMAT plan, 95% and 100% of all points created lie below ±5% for 6 MV and 10 MV photon beam energy, respectively.
Conclusion: In summary, based on the results of preliminary characterization, EPID-based dosimetry is believed as an important tool and beneficial to be implemented for IMRT/VMAT plans verification in Malaysia, especially for in vivo verification, alongside existing pre-treatment verification.
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13
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Shin DS, Kim TH, Rah JE, Kim D, Yang HJ, Lee SB, Lim YK, Jeong J, Kim H, Shin D, Son J. Assessment of a Therapeutic X-ray Radiation Dose Measurement System Based on a Flexible Copper Indium Gallium Selenide Solar Cell. SENSORS (BASEL, SWITZERLAND) 2022; 22:5819. [PMID: 35957376 PMCID: PMC9370937 DOI: 10.3390/s22155819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Revised: 08/02/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Several detectors have been developed to measure radiation doses during radiotherapy. However, most detectors are not flexible. Consequently, the airgaps between the patient surface and detector could reduce the measurement accuracy. Thus, this study proposes a dose measurement system based on a flexible copper indium gallium selenide (CIGS) solar cell. Our system comprises a customized CIGS solar cell (with a size 10 × 10 cm2 and thickness 0.33 mm), voltage amplifier, data acquisition module, and laptop with in-house software. In the study, the dosimetric characteristics, such as dose linearity, dose rate independence, energy independence, and field size output, of the dose measurement system in therapeutic X-ray radiation were quantified. For dose linearity, the slope of the linear fitted curve and the R-square value were 1.00 and 0.9999, respectively. The differences in the measured signals according to changes in the dose rates and photon energies were <2% and <3%, respectively. The field size output measured using our system exhibited a substantial increase as the field size increased, contrary to that measured using the ion chamber/film. Our findings demonstrate that our system has good dosimetric characteristics as a flexible in vivo dosimeter. Furthermore, the size and shape of the solar cell can be easily customized, which is an advantage over other flexible dosimeters based on an a-Si solar cell.
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Affiliation(s)
- Dong-Seok Shin
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Tae-Ho Kim
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Jeong-Eun Rah
- Department of Radiation Oncology, Myongji Hospital, Goyang 10475, Korea
| | - Dohyeon Kim
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Hye Jeong Yang
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Se Byeong Lee
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Young Kyung Lim
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Jonghwi Jeong
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Haksoo Kim
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Dongho Shin
- Proton Therapy Center, National Cancer Center, Goyang 10408, Korea
| | - Jaeman Son
- Department of Radiation Oncology, Seoul National University Hospital, Seoul 03080, Korea
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14
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Ghaempanah H, Tavakoli M, Deevband MR, Alvar AA, Najafi M, Kelley P. Electronic portal image enhancement based on nonuniformity correction in wavelet domain. Med Phys 2022; 49:4599-4612. [DOI: 10.1002/mp.15672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 04/04/2022] [Accepted: 04/04/2022] [Indexed: 11/11/2022] Open
Affiliation(s)
- Hanieh Ghaempanah
- Department of Biomedical Engineering and Medical Physics Faculty of Medicine Shahid Beheshti University of Medical Sciences Tehran Iran
| | - Meysam Tavakoli
- Department of Radiation Oncology University of Pittsburgh School of Medicine and UPMC Hillman Cancer Center Pittsburgh PA USA
- Department of Radiation Oncology UT Southwestern Medical Center Dallas TX USA
| | - Mohammad Reza Deevband
- Department of Biomedical Engineering and Medical Physics Faculty of Medicine Shahid Beheshti University of Medical Sciences Tehran Iran
| | - Amin Asgharzadeh Alvar
- Department of Biomedical Engineering and Medical Physics Faculty of Medicine Shahid Beheshti University of Medical Sciences Tehran Iran
| | - Mohsen Najafi
- Department of Biomedical Engineering and Medical Physics Faculty of Medicine Shahid Beheshti University of Medical Sciences Tehran Iran
| | - Patrick Kelley
- Department of Physics Indiana University‐Purdue University Indianapolis Indiana USA
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15
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Fiagan YA, Bossuyt E, Machiels M, Nevens D, Billiet C, Poortmans P, Gevaert T, Verellen D. Comparing treatment uncertainty for ultra- vs. standard-hypofractionated breast radiation therapy based on in-vivo dosimetry. Phys Imaging Radiat Oncol 2022; 22:85-90. [PMID: 35602547 PMCID: PMC9117915 DOI: 10.1016/j.phro.2022.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 11/26/2022] Open
Abstract
Background and purpose Postoperative ultrahypofractionated radiation therapy (UHFRT) in 5 fractions (fx) for breast cancer patients is as effective and safe as conventionally hypofractionated RT (HFRT) in 15 fx, liberating time for higher-level daily online Image-Guided Radiation Therapy (IGRT) corrections. In this retrospective study, treatment uncertainties occurring in patients treated with 5fx (5fx-group) were evaluated using electronic portal imaging device (EPID)-based in-vivo dosimetry (EIVD) and compared with the results from patients treated with conventionally HFRT (15fx-group) to validate the new technique and to evaluate if the shorter treatment schedule could have a positive effect on the treatment uncertainties. Materials and methods EPID-based integrated transit dose images were acquired for each treatment fraction in the 5fx-group (203 patients) and on the first 3 days of treatment and weekly thereafter in the 15fx-group (203 patients). A total of 1015 EIVD measurements in the 5fx-group and 1144 in the 15fx-group were acquired. Of the latter group, 755 had been treated with online IGRT correction (i.e., Online-IGRT 15fx-group). Results In the 15fx-group 12.0% of fractions failed (FFs) compared to 3.8% in the 5fx-group and 6.9% in the online-IGRT 15fx-group. Causes for FFs in the 15fx-group compared with the 5fx-group were patient positioning (7.4% vs. 2.2%), technical issues (3.1% vs. 1.2%) and breast swelling (1.4% vs. 0.5%). In the online-IGRT 15fx-group, 2.5% were attributed to patient positioning, 3.8% to technical issues and 0.5% to breast swelling. Conclusions EIVD demonstrated that UHFRT for breast cancer results in less FFs compared to standard HFRT. A large proportion of this decrease could be explained by using daily online IGRT.
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O'Connell J, Bazalova‐Carter M. Investigation of image quality of MV and kV CBCT with low‐Z beams and high DQE detector. Med Phys 2022; 49:2334-2341. [DOI: 10.1002/mp.15503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 01/06/2022] [Accepted: 01/20/2022] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jericho O'Connell
- Department of Physics and Astronomy University of Victoria Victoria BC V8W 2Y2 Canada
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17
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A Large Area Pixelated Silicon Array Detector for Independent Transit In Vivo Dosimetry. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12020537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A large area pixelated silicon array detector named “MP987” has been developed for in vivo dosimetry. The detector was developed to overcome the non-water equivalent response of EPID (Electronic Portal Imaging Device) dosimetry systems, due to the shortfalls of the extensive corrections required. The detector, readout system and software have all been custom designed to be operated independently from the linac with the array secured directly above the EPID, to be used in combination with the 6 MV imaging system. Dosimetry characterisation measurements of percentage depth dose (PDD), dose rate dependence, radiation damage, output factors (OF), profile measurements, linearity and uniformity were performed. Additionally, the first pre-clinical tests with this novel detector of a transit dosimetry characterization and a collapsed IMRT (intensity-modulated radiation therapy) study are presented. Both PDD and OF measurements had a percentage difference of less than 2.5% to the reference detector. A maximum change in sensitivity of 4.3 ± 0.3% was observed after 30 kGy of gamma accumulated dose. Transit dosimetry measurements through a homogeneous Solid Water phantom had a measured dose within error of the TPS calculations, for field sizes between 3 × 3 cm2 and 10 × 10 cm2. A four-fraction collapsed IMRT plan on a lung phantom had absolute dose pass fractions between the MP987 and TPS (treatment planning system) from 94.2% to 97.4%, with a 5%/5 mm criteria. The ability to accurately measure dose at a transit level, without the need for correction factors derived from extensive commissioning data collection procedures, makes the MP987 a viable alternative to the EPID for in vivo dosimetry. This MP987 is this first of its kind to be successfully developed specifically for a dual detector application.
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18
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Mans A, Rozendaal R, Janssen T, Damen E, Kaas J, van Mourik A, Mijnheer B. Reduction of systematic dosimetric uncertainties in volumetric modulated arc therapy triggered by patient-specific quality assurance. Phys Imaging Radiat Oncol 2022; 21:6-10. [PMID: 35106384 PMCID: PMC8789528 DOI: 10.1016/j.phro.2022.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 12/24/2021] [Accepted: 01/07/2022] [Indexed: 10/27/2022] Open
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O'Connell J, Bazalova-Carter M. fastCAT: Fast cone beam CT (CBCT) simulation. Med Phys 2021; 48:4448-4458. [PMID: 34053094 DOI: 10.1002/mp.15007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To develop fastCAT, a fast cone-beam computed tomography (CBCT) simulator. fastCAT uses pre-calculated Monte Carlo (MC) CBCT phantom-specific scatter and detector response functions to reduce simulation time for megavoltage (MV) and kilovoltage (kV) CBCT imaging. METHODS Pre-calculated x-ray beam energy spectra, detector optical spread functions and energy deposition, and phantom scatter kernels are combined with GPU raytracing to produce CBCT volumes. MV x-ray beam spectra are simulated with EGSnrc for 2.5- and 6 MeV electron beams incident on a variety of target materials and kV x-ray beam spectra are calculated analytically for an x-ray tube with a tungsten anode. Detectors were modeled in Geant4 extended by Topas and included optical transport in the scintillators. Two MV detectors were modeled-a standard Varian AS1200 GOS detector and a novel CWO high detective quantum efficiency detector. A kV CsI detector was also modeled. Energy-dependent scatter kernels were created in Topas for two 16 cm diameter phantoms: A Catphan 515 contrast phantom and an anthropomorphic head phantom. The Catphan phantom contained inserts of 1-5 mm in diameter of six different tissue types: brain, deflated lung, compact and cortical bone, adipose, and B-100. RESULTS fastCAT simulations retain high fidelity to measurements and MC simulations: MTF curves were within 3.5% and 1.2% of measured values for the CWO and GOS detectors, respectively. HU values and CNR in a fastCAT Catphan 515 simulation were seen to be within 95% confidence intervals of an equivalent MC simulation for all of the tissues with root mean squared errors less than 16 HU and 1.6 in HU values and CNR comparisons, respectively. The anthropomorphic head phantom CWO detector CBCT image resulted in much higher tissue contrast and lower noise compared to the GOS detector CBCT image. A fastCAT simulation of the Catphan 515 module with an image size of 1024 × 1024 × 10 voxels took 61 s on a GPU while the equivalent Topas MC was estimated to take more than 0.3 CPU years. CONCLUSIONS We present an open source fast CBCT simulation with high fidelity to MC simulations. The fastCAT python package can be found at https://github.com/jerichooconnell/fastCAT.git.
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Affiliation(s)
- Jericho O'Connell
- Department of Physics and Astronomy, University of Victoria, Victoria, BC, V8P 5C2, Canada
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20
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Inui S, Ueda Y, Ono S, Ohira S, Isono M, Nitta Y, Ueda H, Miyazaki M, Koizumi M, Teshima T. Evaluation of two-dimensional electronic portal imaging device using integrated images during volumetric modulated arc therapy for prostate cancer. ACTA ACUST UNITED AC 2021; 26:281-290. [PMID: 34211779 DOI: 10.5603/rpor.a2021.0041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 02/08/2021] [Indexed: 01/04/2023]
Abstract
Background The aim of the study was to evaluate analysis criteria for the identification of the presence of rectal gas during volumetric modulated arc therapy (VMAT) for prostate cancer patients by using electronic portal imaging device (EPID)-based in vivo dosimetry (IVD). Materials and methods All measurements were performed by determining the cumulative EPID images in an integrated acquisition mode and analyzed using PerFRACTION commercial software. Systematic setup errors were simulated by moving the anthropomorphic phantom in each translational and rotational direction. The inhomogeneity regions were also simulated by the I'mRT phantom attached to the Quasar phantom. The presence of small and large air cavities (12 and 48 cm3) was controlled by moving the Quasar phantom in several timings during VMAT. Sixteen prostate cancer patients received EPID-based IVD during VMAT. Results In the phantom study, no systematic setup error was detected in the range that can happen in clinical (< 5-mm and < 3 degree). The pass rate of 2% dose difference (DD2%) in small and large air cavities was 98.74% and 79.05%, respectively, in the appearance of the air cavity after irradiation three quarter times. In the clinical study, some fractions caused a sharp decline in the DD2% pass rate. The proportion for DD2% < 90% was 13.4% of all fractions. Rectal gas was confirmed in 11.0% of fractions by acquiring kilo-voltage X-ray images after the treatment. Conclusions Our results suggest that analysis criteria of 2% dose difference in EPID-based IVD was a suitable method for identification of rectal gas during VMAT for prostate cancer patients.
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Affiliation(s)
- Shoki Inui
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan.,Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshihiro Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Shunsuke Ono
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Shingo Ohira
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Masaru Isono
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Yuya Nitta
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Hikari Ueda
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Masayoshi Miyazaki
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
| | - Masahiko Koizumi
- Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita, Japan
| | - Teruki Teshima
- Department of Radiation Oncology, Osaka International Cancer Institute, Osaka, Japan
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21
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Muñoz D, Olaciregui-Ruiz I, Norberg G, van der Heide UA, Mans A. Characterization of Gas Electron Multiplier-based detector for external beam radiation therapy dosimetry. Med Phys 2021; 48:1931-1940. [PMID: 33440024 DOI: 10.1002/mp.14718] [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: 08/19/2020] [Revised: 12/22/2020] [Accepted: 12/26/2020] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Electronic portal imaging devices (EPIDs) are commonly installed on modern linear accelerators (LINACs) and are convenient for imaging and, potentially, dosimetry. However, owing to their construction with metal and scintillating layers of high atomic number, they exhibit nonwater-equivalent response and oversensitivity to low-energy photons. Therefore, EPIDs are not ideal for dosimetry purposes. Additionally, nonlinearities due to the combined use of scintillators and photodiodes have been reported. Here, an EPID which employs a variable gain Gas Electron Multiplier (GEM) and direct detection of electrons is introduced. To investigate its dosimetric performance, measurements characterizing the novel EPID are performed and compared with measurements from ionization chambers and conventional EPIDs. METHODS Linearity, dose rate dependence, field size dependence, off-axis response, and transmission response were measured for all available energy settings (6, 10, 6 MV Flattening Filter Free (FFF) and 10 MVFFF) using three different detector gain settings. Additionally, an evaluation of the ghosting and image lag of the panel was completed. Reference ionization chamber measurements were performed for the off-axis and transmission response and existing data for conventional EPIDs and ionization chambers from equivalent measurements were used for comparison of the field size dependence. Elsewhere, values from the linac monitoring chambers were used. RESULTS In the range from 10 to 1000 Monitor Units (MU), the detector was linear within 1% for all combinations of gain settings and energies. The dose rate dependence was also within 1% for all energies and for two out of three gain settings. Regarding field size dependency, the ratio of ionization chamber and panel values was 0.94 and 0.98 for the conventional EPID and GEMini respectively, at 20 × 20 cm2 and 10 MV. For 6 MV, 6 MVFFF, and 10MVFFF these ratios were 0.97, 0.98, and 0.99 for the GEMini, and 0.95, 0.97, and 0.97 for the conventional EPID. Similar performance between the GEMini and conventional EPID is observed for field sizes smaller than 10 × 10 cm2 . The transmission response was within 5% for all energies for thicknesses up to 30 cm, compared to 10-20% for a conventional EPID. The off-axis response for shifts up to 16 cm was within 1% and 3% for 6 MV and 10 MV, with and without phantom. The rise and fall of the signal from the detector correspond well to monitor chamber measurements indicating little ghosting and image lag, regardless of gain setting. CONCLUSION The GEM EPID exhibits dose rate dependence and linearity within 1%, and negligible ghosting and image lag. In this regard, it performs particularly well using 50 and 250 V of gain, and either could be chosen. For higher sensitivity, 250 V is the recommended base gain setting, although other applications may warrant different gains. For most tests performed in this study, the GEM EPID demonstrates a more water-equivalent response than conventional EPIDs making GEMs a viable technology for dosimetry in radiation therapy.
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Affiliation(s)
- Daniel Muñoz
- C-RAD Imaging AB, Uppsala, Sweden.,Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
| | - Igor Olaciregui-Ruiz
- Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
| | | | - Uulke A van der Heide
- Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
| | - Anton Mans
- Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands
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22
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Esposito M, Piermattei A, Bresciani S, Orlandini LC, Falco MD, Giancaterino S, Cilla S, Ianiro A, Nigro R, Botez L, Riccardi S, Fidanzio A, Greco F, Villaggi E, Russo S, Stasi M. Improving dose delivery accuracy with EPID in vivo dosimetry: results from a multicenter study. Strahlenther Onkol 2021; 197:633-643. [PMID: 33594471 DOI: 10.1007/s00066-021-01749-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 01/22/2021] [Indexed: 12/26/2022]
Abstract
PURPOSE To investigate critical aspects and effectiveness of in vivo dosimetry (IVD) tests obtained by an electronic portal imaging device (EPID) in a multicenter and multisystem context. MATERIALS AND METHODS Eight centers with three commercial systems-SoftDiso (SD, Best Medical Italy, Chianciano, Italy), Dosimetry Check (DC, Math Resolution, LCC), and PerFRACTION (PF, Sun Nuclear Corporation, SNC, Melbourne, FL)-collected IVD results for a total of 2002 patients and 32,276 tests. Data are summarized for IVD software, radiotherapy technique, and anatomical site. Every center reported the number of patients and tests analyzed, and the percentage of tests outside of the tolerance level (OTL%). OTL% was categorized as being due to incorrect patient setup, incorrect use of immobilization devices, incorrect dose computation, anatomical variations, and unknown causes. RESULTS The three systems use different approaches and customized alert indices, based on local protocols. For Volumetric Modulated Arc Therapy (VMAT) treatments OTL% mean values were up to 8.9% for SD, 18.0% for DC, and 16.0% for PF. Errors due to "anatomical variations" for head and neck were up to 9.0% for SD and DC and 8.0% for PF systems, while for abdomen and pelvis/prostate treatments were up to 9%, 17.0%, and 9.0% for SD, DC, and PF, respectively. The comparison among techniques gave 3% for Stereotactic Body Radiation Therapy, 7.0% (range 4.7-8.9%) for VMAT, 10.4% (range 7.0-12.2%) for Intensity Modulated Radiation Therapy, and 13.2% (range 8.8-21.0%) for 3D Conformal Radiation Therapy. CONCLUSION The results obtained with different IVD software and among centers were consistent and showed an acceptable homogeneity. EPID IVD was effective in intercepting important errors.
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Affiliation(s)
- M Esposito
- S. C. Fisica Sanitaria Firenze-Empoli, Medical Physics Unit of Radiation Oncology Dept., Azienda Sanitaria USL Toscana Centro Florence, Via dell'Antella 58, 50012, Bagno a Ripoli, Firenze, Italy.
| | - A Piermattei
- UOC di Fisica Sanitaria, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - S Bresciani
- Medical Physics, Candiolo Cancer Institute-FPO IRCCS, Turin, Italy
| | - L C Orlandini
- Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, China
| | - M D Falco
- Dipartimento di Radioterapia, Università di Chieti, Chieti, Italy
| | - S Giancaterino
- Dipartimento di Radioterapia, Università di Chieti, Chieti, Italy
| | - S Cilla
- Medical Physics Unit, Fondazione di ricerca e cura "Giovanni Paolo II", Campobasso, Italy
| | - A Ianiro
- Medical Physics Unit, Fondazione di ricerca e cura "Giovanni Paolo II", Campobasso, Italy
| | - R Nigro
- OGP S. Camillo de Lellis, Rieti, Italy
| | - L Botez
- Medical Physics, Candiolo Cancer Institute-FPO IRCCS, Turin, Italy
| | | | - A Fidanzio
- UOC di Fisica Sanitaria, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | - F Greco
- UOC di Fisica Sanitaria, Radioterapia Oncologica ed Ematologia, Fondazione Policlinico Universitario "A. Gemelli" IRCCS, Rome, Italy
| | | | - S Russo
- S. C. Fisica Sanitaria Firenze-Empoli, Azienda Sanitaria USL Toscana Centro Florence, Florence, Italy
| | - M Stasi
- S.C. Fisica Sanitaria, A.O. Ordine Mauriziano di Torino, Torino, Italy
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23
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Harris TC, Seco J, Ferguson D, Lehmann M, Huber P, Shi M, Jacobson M, Valencia Lozano I, Myronakis M, Baturin P, Fueglistaller R, Morf D, Berbeco R. Clinical translation of a new flat-panel detector for beam's-eye-view imaging. Phys Med Biol 2020; 65:225004. [PMID: 33284786 PMCID: PMC9142212 DOI: 10.1088/1361-6560/abb571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Electronic portal imaging devices (EPIDs) lend themselves to beams-eye view clinical applications, such as tumor tracking, but are limited by low contrast and detective quantum efficiency (DQE). We characterize a novel EPID prototype consisting of multiple layers and investigate its suitability for use under clinical conditions. A prototype multi-layer imager (MLI) was constructed utilizing four conventional EPID layers, each consisting of a copper plate, a Gd2O2S:Tb phosphor scintillator, and an amorphous silicon flat panel array detector. We measured the detector's response to a 6 MV photon beam with regards to modulation transfer function, noise power spectrum, DQE, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), and the linearity of the detector's response to dose. Additionally, we compared MLI performance to the single top layer of the MLI and the standard Varian AS-1200 detector. Pre-clinical imaging was done on an anthropomorphic phantom, and the detector's CNR, SNR and spatial resolution were assessed in a clinical environment. Images obtained from spine and liver patient treatment deliveries were analyzed to verify CNR and SNR improvements. The MLI has a DQE(0) of 9.7%, about 5.7 times the reference AS-1200 detector. Improved noise performance largely drives the increase. CNR and SNR of clinical images improved three-fold compared to reference. A novel MLI was characterized and prepared for clinical translation. The MLI substantially improved DQE and CNR performance while maintaining the same resolution. Pre-clinical tests on an anthropomorphic phantom demonstrated improved performance as predicted theoretically. Preliminary patient data were analyzed, confirming improved CNR and SNR. Clinical applications are anticipated to include more accurate soft tissue tracking.
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Affiliation(s)
- T C Harris
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
- BioMedical Physics in Radiation Oncology, DKFZ, Heidelberg, Germany
- Department of Physics, University of Heidelberg, Heidelberg, Germany
| | - J Seco
- BioMedical Physics in Radiation Oncology, DKFZ, Heidelberg, Germany
- Department of Physics, University of Heidelberg, Heidelberg, Germany
| | - D Ferguson
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
| | - M Lehmann
- Varian Medical Systems, Baden-Dattwil, Switzerland
| | - P Huber
- Varian Medical Systems, Baden-Dattwil, Switzerland
| | - M Shi
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
- University of Massachusetts Lowell, Lowell, MA, United States of America
| | - M Jacobson
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
| | - I Valencia Lozano
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
| | - M Myronakis
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
| | - P Baturin
- Varian Medical System, Palo Alto, CA, United States of America
| | | | - D Morf
- Varian Medical Systems, Baden-Dattwil, Switzerland
| | - R Berbeco
- Department of Radiation Oncology, Dana Farber/Brigham and Women's Cancer Center, Harvard Medical school, Boston, MA, United States of America
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24
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Bossuyt E, Weytjens R, Nevens D, De Vos S, Verellen D. Evaluation of automated pre-treatment and transit in-vivo dosimetry in radiotherapy using empirically determined parameters. PHYSICS & IMAGING IN RADIATION ONCOLOGY 2020; 16:113-129. [PMID: 33458354 PMCID: PMC7807610 DOI: 10.1016/j.phro.2020.09.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 08/07/2020] [Accepted: 09/23/2020] [Indexed: 11/16/2022]
Abstract
Background and purpose First reports on clinical use of commercially automated systems for Electronic Portal Imaging Device (EPID)-based dosimetry in radiotherapy showed the capability to detect important changes in patient setup, anatomy and external device position. For this study, results for more than 3000 patients, for both pre-treatment verification and in-vivo transit dosimetry were analyzed. Materials and methods For all Volumetric Modulated Arc Therapy (VMAT) plans, pre-treatment quality assurance (QA) with EPID images was performed. In-vivo dosimetry using transit EPID images was analyzed, including causes and actions for failed fractions for all patients receiving photon treatment (2018-2019). In total 3136 and 32,632 fractions were analyzed with pre-treatment and transit images respectively. Parameters for gamma analysis were empirically determined, balancing the rate between detection of clinically relevant problems and the number of false positive results. Results Pre-treatment and in-vivo results depended on machine type. Causes for failed in-vivo analysis included deviations in patient positioning (32%) and anatomy change (28%). In addition, errors in planning, imaging, treatment delivery, simulation, breath hold and with immobilization devices were detected. Actions for failed fractions were mostly to repeat the measurement while taking extra care in positioning (54%) and to intensify imaging procedures (14%). Four percent initiated plan adjustments, showing the potential of the system as a basis for adaptive planning. Conclusions EPID-based pre-treatment and in-vivo transit dosimetry using a commercially available automated system efficiently revealed a wide variety of deviations and showed potential to serve as a basis for adaptive planning.
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Affiliation(s)
- Evy Bossuyt
- Iridium Kankernetwerk, Radiation Oncology Department, Antwerp, Belgium
| | | | - Daan Nevens
- Iridium Kankernetwerk, Radiation Oncology Department, Antwerp, Belgium.,Faculty of Medicine and Health Sciences, Antwerp University, Antwerp, Belgium
| | - Sarah De Vos
- Iridium Kankernetwerk, Radiation Oncology Department, Antwerp, Belgium
| | - Dirk Verellen
- Iridium Kankernetwerk, Radiation Oncology Department, Antwerp, Belgium.,Faculty of Medicine and Health Sciences, Antwerp University, Antwerp, Belgium
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25
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Esposito M, Ghirelli A, Pini S, Alpi P, Barca R, Fondelli S, Grilli Leonulli B, Paoletti L, Rossi F, Bastiani P, Russo S. Clinical implementation of 3D in vivo dosimetry for abdominal and pelvic stereotactic treatments. Radiother Oncol 2020; 154:14-20. [PMID: 32926910 DOI: 10.1016/j.radonc.2020.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/31/2022]
Abstract
PURPOSE To analyze results from three years of in vivo transit EPID dosimetry of abdominal and pelvic stereotactic radiotherapy and to establish tolerance levels for routine clinical use. MATERIAL 80 stereotactic VMAT treatments (152 fractions) targeting the abdomen or pelvis were analyzed. In vivo 3D doses were reconstructed with an EPID commercial algorithm. Gamma Agreement Index (GAI) and DVH differences in Planning Target Volume (PTV) and Clinical Target Volume (CTV) were evaluated. Initial tolerance level was set to GAI > 85% in PTV. Fractions Over Tolerance Level (OTL) were deemed to be due to set-up errors, incorrect use of immobilization devices, 4D errors, transit EPID algorithm errors and unknown/unidentified errors. Statistical Process Control (SPC) was applied to determine local tolerance levels. RESULTS Average GAI were (82.7 ± 20.9) % in PTV and (72.9 ± 29.7) % in CTV. 37.8% of fractions resulted OTL and were classified as: set-up errors (3.3%), incorrect use of immobilization devices (2.1%), 4D errors (2.1%), EPID transit algorithm errors (17.1%). OTL causes for the remaining 13.2% of fractions were not identified. The differences between PTV and CTV measured in vivo and calculated mean dose (average difference ± standard deviation) were (-3.3% ± 3.2%) and (-2.3% ± 3.0%). When tolerance levels based on SPC to PTV mean dose differences were applied, the percentage of OTL decreased to 7% and no EPID algorithm error occurred. One error was not identified. CONCLUSIONS The application of local tolerance levels to EPID in vivo dosimetry proved to be useful for detecting extra-lung SBRT treatment errors.
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Affiliation(s)
- Marco Esposito
- S. C. Fisica Sanitaria, Firenze - Azienda USL Toscana Centro, Italy.
| | | | - Silvia Pini
- S. C. Fisica Sanitaria, Firenze - Azienda USL Toscana Centro, Italy
| | - Paolo Alpi
- S. C. Radioterapia, Firenze - Azienda USL Toscana Centro, Italy
| | - Raffaella Barca
- S. C. Radioterapia, Firenze - Azienda USL Toscana Centro, Italy
| | - Simona Fondelli
- S. C. Radioterapia, Firenze - Azienda USL Toscana Centro, Italy
| | | | - Lisa Paoletti
- S. C. Radioterapia, Firenze - Azienda USL Toscana Centro, Italy
| | - Francesca Rossi
- S. C. Radioterapia, Firenze - Azienda USL Toscana Centro, Italy
| | - Paolo Bastiani
- S. C. Radioterapia, Firenze - Azienda USL Toscana Centro, Italy
| | - Serenella Russo
- S. C. Fisica Sanitaria, Firenze - Azienda USL Toscana Centro, Italy
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26
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Rajasekar A, Moggré A, Cousins A, Marsh S. Optimising the use of EPIgray for 3DCRT breast treatments. Phys Eng Sci Med 2020; 43:1077-1085. [PMID: 32696435 DOI: 10.1007/s13246-020-00904-0] [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: 01/21/2020] [Accepted: 07/14/2020] [Indexed: 11/29/2022]
Abstract
EPIgray is an in-vivo dosimetry system which uses electronic portal images to calculate dose delivered to a point of interest (POI) and the percentage dose difference (%DDiff) from expected dose. For 3D conformal radiotherapy (3DCRT) of breasts, a small shift between patient position on treatment compared to the planning CT is often clinically accepted. However due to the use of the planning CT in the EPIgray back-projection algorithm, acceptable shifts can have undue impact on EPIgray dose so it does not reflect true POI dose. At our centre ± 5.0% %DDiff tolerance is used for all treatment sites, however for breast treatments this effect causes false positive (FP) results, which may mean an actual treatment error is not detected. Patient position can be better represented within EPIgray using a contour correction (CC) method, increasing dose calculation accuracy. A custom breast-lung phantom was developed to validate use of CC, then EPIgray data of 30 breast patients were retrospectively analysed with CC. %DDiff before and after CC identified a FP rate. A process to determine optimal EPIgray tolerances for breast 3DCRT to reduce incidence of FP results is presented, based on analysis of factors influencing %DDiff and a receiver operator characteristic curve analysis of the retrospective study data. This process determined that a reduced tolerance of ± 3.5% would optimise utility of the EPIgray results, but this would require additional clinical resources to investigate the correspondingly increased rate of false negative results. Choice of tolerance requires consideration of workload and aims of the IVD program.
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Affiliation(s)
- Abinaya Rajasekar
- Department of Medical Physics and Bioengineering, Christchurch Hospital, Canterbury, New Zealand. .,Department of Physics and Astronomy, University of Canterbury, Canterbury, New Zealand.
| | - Alicia Moggré
- Department of Medical Physics and Bioengineering, Christchurch Hospital, Canterbury, New Zealand
| | - Andrew Cousins
- Department of Medical Physics and Bioengineering, Christchurch Hospital, Canterbury, New Zealand
| | - Steven Marsh
- Department of Physics and Astronomy, University of Canterbury, Canterbury, New Zealand
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27
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Olaciregui-Ruiz I, Beddar S, Greer P, Jornet N, McCurdy B, Paiva-Fonseca G, Mijnheer B, Verhaegen F. In vivo dosimetry in external beam photon radiotherapy: Requirements and future directions for research, development, and clinical practice. Phys Imaging Radiat Oncol 2020; 15:108-116. [PMID: 33458335 PMCID: PMC7807612 DOI: 10.1016/j.phro.2020.08.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 11/18/2022] Open
Abstract
External beam radiotherapy with photon beams is a highly accurate treatment modality, but requires extensive quality assurance programs to confirm that radiation therapy will be or was administered appropriately. In vivo dosimetry (IVD) is an essential element of modern radiation therapy because it provides the ability to catch treatment delivery errors, assist in treatment adaptation, and record the actual dose delivered to the patient. However, for various reasons, its clinical implementation has been slow and limited. The purpose of this report is to stimulate the wider use of IVD for external beam radiotherapy, and in particular of systems using electronic portal imaging devices (EPIDs). After documenting the current IVD methods, this report provides detailed software, hardware and system requirements for in vivo EPID dosimetry systems in order to help in bridging the current vendor-user gap. The report also outlines directions for further development and research. In vivo EPID dosimetry vendors, in collaboration with users across multiple institutions, are requested to improve the understanding and reduce the uncertainties of the system and to help in the determination of optimal action limits for error detection. Finally, the report recommends that automation of all aspects of IVD is needed to help facilitate clinical adoption, including automation of image acquisition, analysis, result interpretation, and reporting/documentation. With the guidance of this report, it is hoped that widespread clinical use of IVD will be significantly accelerated.
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Affiliation(s)
- Igor Olaciregui-Ruiz
- Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Sam Beddar
- Division of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Peter Greer
- Calvary Mater Newcastle Hospital and University of Newcastle, Newcastle, New South Wales, Australia
| | - Nuria Jornet
- Servei de Radiofísica i Radioprotecció, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Boyd McCurdy
- Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba, Canada
| | - Gabriel Paiva-Fonseca
- Department of Radiation Oncology (Maastro), GROW School for Oncology, Maastricht University Medical Centre+, Maastricht, the Netherlands
| | - Ben Mijnheer
- Department of Radiation Oncology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Frank Verhaegen
- Department of Radiation Oncology (Maastro), GROW School for Oncology, Maastricht University Medical Centre+, Maastricht, the Netherlands
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28
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Esposito M, Villaggi E, Bresciani S, Cilla S, Falco MD, Garibaldi C, Russo S, Talamonti C, Stasi M, Mancosu P. Estimating dose delivery accuracy in stereotactic body radiation therapy: A review of in-vivo measurement methods. Radiother Oncol 2020; 149:158-167. [PMID: 32416282 DOI: 10.1016/j.radonc.2020.05.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 05/08/2020] [Accepted: 05/10/2020] [Indexed: 12/25/2022]
Abstract
Stereotactic body radiation therapy (SBRT) has been recognized as a standard treatment option for many anatomical sites. Sophisticated radiation therapy techniques have been developed for carrying out these treatments and new quality assurance (QA) programs are therefore required to guarantee high geometrical and dosimetric accuracy. This paper focuses on recent advances on in-vivo measurements methods (IVM) for SBRT treatment. More specifically, all of the online QA methods for estimating the effective dose delivered to patients were compared. Determining the optimal IVM for performing SBRT treatments would reduce the risk of errors that could jeopardize treatment outcome. A total of 89 papers were included. The papers were subdivided into the following topics: point dosimeters (PD), transmission detectors (TD), log file analysis (LFA), electronic portal imaging device dosimetry (EPID), dose accumulation methods (DAM). The detectability capability of the main IVM detectors/devices were evaluated. All of the systems have some limitations: PD has no spatial data, EPID has limited sensitivity towards set-up errors and intra-fraction motion in some anatomical sites, TD is insensitive towards patient related errors, LFA is not an independent measure, DAMs are not always based on measures. In order to minimize errors in SBRT dose delivery, we recommend using synergic combinations of two or more of the systems described in our review: on-line tumor position and patient information should be combined with MLC position and linac output detection accuracy. In this way the effects of SBRT dose delivery errors will be reduced.
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Affiliation(s)
- Marco Esposito
- S.C. Fisica Sanitaria Firenze-Empoli, Azienda Sanitaria USL Toscana Centro, Italy.
| | | | - Sara Bresciani
- Medical Physics, Candiolo Cancer Institute - FPO IRCCS, Turin, Italy
| | - Savino Cilla
- Medical Physics Unit, Gemelli Molise Hospital, Campobasso, Italy
| | - Maria Daniela Falco
- Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Cristina Garibaldi
- Radiation Research Unit, European Institute of Oncology IRCCS, Milan, Italy
| | - Serenella Russo
- S.C. Fisica Sanitaria Firenze-Empoli, Azienda Sanitaria USL Toscana Centro, Italy
| | - Cinzia Talamonti
- University of Florence, Dept Biomedical Experimental and Clinical Science, "Mario Serio", Medical Physics Unit, AOU Careggi, Florence, Italy
| | - Michele Stasi
- Medical Physics, Candiolo Cancer Institute - FPO IRCCS, Turin, Italy
| | - Pietro Mancosu
- Medical Physics Unit of Radiotherapy Dept., Humanitas Clinical and Research Hospital - IRCCS, Rozzano, Italy
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29
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Liao X, Wu F, Wu J, Peng Q, Yao X, Kang S, Zhao Y, Orlandini LC. Impact of positioning errors in the dosimetry of VMAT left-sided post mastectomy irradiation. Radiat Oncol 2020; 15:103. [PMID: 32381103 PMCID: PMC7206823 DOI: 10.1186/s13014-020-01556-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 04/28/2020] [Indexed: 12/25/2022] Open
Abstract
Background Volumetric modulated arc therapy (VMAT) adopted in post-mastectomy radiation therapy (PMRT) has the capacity to achieve highly conformal dose distributions. The research aims to evaluate the impact of positioning errors in the dosimetry of VMAT left-sided PMRT. Methods A total of 18 perturbations where introduced in 11 VMAT treatment plans that shifted the isocenter from its reference position of 3, 5, 10 mm in six directions. The thoracic wall and supraclavicular clinical target volumes (CTVs), the heart and the left lung dose volume histograms (DVHs) of 198 perturbed plans were calculated. The absolute differences (∆) of the mean dose (Dm) and DVH endpoints Vx and Dy (percentage volume receiving x Gy, and dose covering y% of the volume, respectively) were used to compare the dosimetry of the reference vs perturbed plans. Results Isocenter shifts in the anterior and lateral directions lead to maximum disagreement between the CTVs dosimetry of perturbed vs reference plans. Isocenter shifts of 10 mm shown a decrease of D95, D98 and Dm of 12.8, 18.0, and 2.9% respectively, for the CTVs. For 5 mm isocenter shifts, these differences decreased to 3.2, 5.2, and 0.9%, respectively, and for 3 mm shifts to 1.0, 1.7, and 0.6%, respectively. For the organs at risk (OARs), only isocenter shifts in the right, posterior and inferior directions worsen the plan dosimetry, nevertheless not negligible lung ∆ V20 of + 2.6%, and heart ∆ V25 of + 1.6% persist for 3 mm shifts. Conclusions Inaccuracy in isocenter positioning for VMAT left-sided PMRT irradiation may impact the dosimetry of the CTVs and OARs to a different extent, depending on the directions and magnitude of the perturbation. The acquired information could be useful for planning strategies to guarantee the accuracy of the treatment delivered.
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Affiliation(s)
- Xiongfei Liao
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
| | - Fan Wu
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
| | - Junxiang Wu
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
| | - Qian Peng
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China.
| | - Xinghong Yao
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
| | - Shengwei Kang
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
| | - Yanqun Zhao
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
| | - Lucia Clara Orlandini
- Sichuan Cancer Hospital & Research Institute, School of Medicine University of Electronic Science and Technology of China, 55th Renmin South Road, 4th Section, Chengdu, 610041, China
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Olaciregui-Ruiz I, Torres-Xirau I, Teuwen J, van der Heide UA, Mans A. A Deep Learning-based correction to EPID dosimetry for attenuation and scatter in the Unity MR-Linac system. Phys Med 2020; 71:124-131. [DOI: 10.1016/j.ejmp.2020.02.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/08/2020] [Accepted: 02/23/2020] [Indexed: 10/24/2022] Open
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Beck L, Velthuis JJ, Fletcher S, Haynes JA, Page RF. Using a TRAPS upstream transmission detector to verify multileaf collimator positions during dynamic radiotherapy delivery. Appl Radiat Isot 2020; 156:108951. [PMID: 31790976 DOI: 10.1016/j.apradiso.2019.108951] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 09/25/2019] [Accepted: 10/21/2019] [Indexed: 12/01/2022]
Abstract
With the advancement of high-precision radiotherapy and the increasing use of higher intensity beams, the risk to the patient increases should the radiotherapy machine malfunction. Hence more accurate treatment verification is required. In this paper we provide a solution for real-time monitoring of X-ray beams from radiotherapy linear accelerators using monolithic active pixel sensors. We show that leaf errors can be detected with high precision in static fields and IMRT step and shoot, and accurate leaf tracking is possible in Volumetric Modulated Arc Therapy. The prototype MAPS detector meets the criteria of 1% attenuation acceptable for clinical use.
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Affiliation(s)
- L Beck
- University of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, BS8 1TL, Bristol, United Kingdom.
| | - J J Velthuis
- University of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, BS8 1TL, Bristol, United Kingdom; Swansea University Medical School, Singleton Park, Swansea, United Kingdom; University of South China, School of Nuclear Science and Technology, West Changsheng Rd, Hengyang, 421001, China
| | - S Fletcher
- United Hospitals Bristol NHS Foundation Trust (UHB), at the Department of Medical Physics & Bioengineering at Bristol Haematology and Oncology Centre, Horfield Road, Bristol, United Kingdom
| | - J A Haynes
- United Hospitals Bristol NHS Foundation Trust (UHB), at the Department of Medical Physics & Bioengineering at Bristol Haematology and Oncology Centre, Horfield Road, Bristol, United Kingdom
| | - R F Page
- University of Bristol, H.H. Wills Physics Laboratory, Tyndall Avenue, BS8 1TL, Bristol, United Kingdom
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Matsushita N, Nakamura M, Sasaki M, Yano S, Yoshimura M, Mizowaki T. Analyses of integrated EPID images for on-treatment quality assurance to account for interfractional variations in volumetric modulated arc therapy. J Appl Clin Med Phys 2020; 21:110-116. [PMID: 31909889 PMCID: PMC6964755 DOI: 10.1002/acm2.12805] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/30/2019] [Accepted: 12/05/2019] [Indexed: 01/03/2023] Open
Abstract
Purpose To investigate the effects of interfractional variation, such as anatomical changes and setup errors, on dose delivery during treatment for prostate cancer (PC) and head and neck cancer (HNC) by courses of volumetric modulated arc therapy (VMAT) aided by on‐treatment electronic portal imaging device (EPID) images. Methods Seven patients with PC and 20 patients with HNC who had received VMAT participated in this study. After obtaining photon fluence at the position of the EPID for each treatment arc from on‐treatment integrated EPID images, we calculated the differences between the fluence for the first fraction and each subsequent fraction for each arc. The passing rates were investigated based on a tolerance level of 3% of the maximum fluence during the treatment courses and the correlations between the passing rates and anatomical changes. Results In PC, the median and lowest passing rates were 99.8% and 95.2%, respectively. No correlations between passing rates and interfractional variation were found. In HNC, the median passing rate of all fractions was 93.0%, and the lowest passing rate was 79.6% during the 35th fraction. Spearman’s correlation coefficients between the passing rates and changes in weight or neck volume were − 0.77 and − 0.74, respectively. Conclusions Analyses of the on‐treatment EPID images facilitates estimates of the interfractional anatomical variation in HNC patients during VMAT and thus improves assessments of the need for re‐planning or adaptive strategies and the timing thereof.
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Affiliation(s)
- Norimasa Matsushita
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan
| | - Mitsuhiro Nakamura
- Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Makoto Sasaki
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan.,Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shinsuke Yano
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan
| | - Michio Yoshimura
- Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Mizowaki
- Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Olaciregui-Ruiz I, Rozendaal R, van Kranen S, Mijnheer B, Mans A. The effect of the choice of patient model on the performance of in vivo 3D EPID dosimetry to detect variations in patient position and anatomy. Med Phys 2019; 47:171-180. [PMID: 31674038 DOI: 10.1002/mp.13893] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 10/09/2019] [Accepted: 10/21/2019] [Indexed: 01/09/2023] Open
Abstract
PURPOSE In vivo EPID dosimetry is meant to trigger on relevant differences between delivered and planned dose distributions and should therefore be sensitive to changes in patient position and patient anatomy. Three-dimensional (3D) EPID back-projection algorithms can use either the planning computed tomography (CT) or the daily patient anatomy as patient model for dose reconstruction. The purpose of this study is to quantify the effect of the choice of patient model on the performance of in vivo 3D EPID dosimetry to detect patient-related variations. METHODS Variations in patient position and patient anatomy were simulated by transforming the reference planning CT images (pCT) into synthetic daily CT images (dCT) representing a variation of a given magnitude in patient position or in patient anatomy. For each variation, synthetic in vivo EPID data were also generated to simulate the reconstruction of in vivo EPID dose distributions. Both the planning CT images and the synthetic daily CT images could be used as patient model in the reconstructions yielding e D pCT and e D dCT EPID reconstructed dose distributions respectively. The accuracy of e D pCT and e D dCT reconstructions was evaluated against absolute dose measurements made in different phantom setups, and against dose distributions calculated by the treatment planning system (TPS). The comparison was performed by γ-analysis (3% local dose/2 mm). The difference in sensitivity between e D pCT and e D dCT reconstructions to detect variations in patient position and in patient anatomy was investigated using receiver operating characteristic analysis and the number of triggered alerts for 100 volumetric modulated arc therapy plans and 12 variations. RESULTS e D dCT showed good agreement with both absolute point dose measurements (<0.5%) and TPS data (γ-mean = 0.52 ± 0.11). The agreement degraded with e D pCT , with the magnitude of the deviation varying with each specific case. e D dCT readily detected combined 3 mm translation setup errors in all directions (AUC = 1.0) and combined 3° rotation setup errors around all axes (AUC = 0.86) whereas e D pCT showed good detectability only for 12 mm translations (AUC = 0.85) and 9° rotations (AUC = 0.80). Conversely, e D pCT manifested a higher sensitivity to patient anatomical changes resulting in AUC values of 0.92/0.95 for a 6 mm patient contour expansion/contraction compared to 0.70/0.64 with e D dCT . Using |ΔPTVD50 | > 3% as clinical tolerance level, the percentage of alerts for 6 mm changes in patient contour were 85%/27% with e D pCT / e D dCT . CONCLUSIONS With planning CT images as patient model, EPID dose reconstructions underestimate the dosimetric effects caused by errors in patient positioning and overestimate the dosimetric effects caused by changes in patient anatomy. The use of the daily patient position and anatomy as patient model for in vivo 3D EPID transit dosimetry improves the ability of the system to detect uncorrected errors in patient position and it reduces the likelihood of false positives due to patient anatomical changes.
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Affiliation(s)
- Igor Olaciregui-Ruiz
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Roel Rozendaal
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Simon van Kranen
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Ben Mijnheer
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Anton Mans
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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Galván De la Cruz O, Rodríguez-Ávila M, Rivera-Montalvo T, García Garduño O. Measurement of percentage dose at the surface for a 6 MV photon beam. Rep Pract Oncol Radiother 2019; 24:585-592. [PMID: 31660051 PMCID: PMC6807031 DOI: 10.1016/j.rpor.2019.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 05/09/2019] [Accepted: 09/21/2019] [Indexed: 11/19/2022] Open
Abstract
AIM To evaluate if a radiochromic film (RF) Gafchromic EBT3 is suitable for surface dose measurements of radiotherapy treatments performed with a 6 MV linear accelerator. Two aspects of RF were analyzed, beam energy dependence and surface dose determination. BACKGROUND The measurements done at the surface or near the radiation source are done without charged electronic equilibrium and also have contribution of electron contamination. The detectors used for these measurements should not alter the dose to the target. To counteract these dosimetric problems it is proposed to do the measurements with radiochromic films which are thin detectors and have tissue equivalent properties. MATERIALS AND METHODS The measurements were done using a Novalis linear accelerator (LINAC) with nominal energy of 6 MV. To determine the surface dose, the total scatter factors (TSF) of three different field sizes were measured in a water phantom at 5 cm depth. Energy dependence of EBT3 was studied at three different depths, using a solid water phantom. The surface measurements were done with the RF for the same field sizes of the TSF measurements. The value of the percentage depth dose was calculated normalizing the doses measured in the RF with the LINAC output, at 5 cm depth, and the TSF. RESULTS The radiochromic films showed almost energy independence, the differences between the curves are 1.7% and 1.8% for the 1.5 cm and 10 cm depth, respectively. The percentage depth doses values at the surface measured for the 10 cm × 10 cm, 5 cm × 5 cm and 1 cm × 1 cm were 26.1 ± 1.3%, 21.3 ± 2.4% and 20.2 ± 2.6%, respectively. CONCLUSIONS The RF-EBT3 seems to be a detector suitable for measurements of the dose at the surface. This suggests that RF-EBT3 films might be good candidates as detectors for in vivo dosimetry.
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Affiliation(s)
- O.O. Galván De la Cruz
- Unidad de Radioneurocirugía, Instituto Nacional de Neurología y Neurocirugía, Insurgentes Sur 3877, México City, Mexico
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, Legaria 694, México city, México
| | - M.A. Rodríguez-Ávila
- Posgrado en Ciencias Físicas, Universidad Nacional Autónoma de México, Instituto de Física, Circuito de la Investigación Científica s/n. Ciudad Universitaria, 04510, Mexico City, México
| | - T. Rivera-Montalvo
- Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Unidad Legaria, Instituto Politécnico Nacional, Legaria 694, México city, México
| | - O.A. García Garduño
- Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía, Insurgentes Sur 3877, México City, México
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Kang S, Li J, Ma J, Zhang W, Liao X, Qing H, Tan T, Xin X, Tang B, Piermattei A, Orlandini LC. Evaluation of interfraction setup variations for postmastectomy radiation therapy using EPID-based in vivo dosimetry. J Appl Clin Med Phys 2019; 20:43-52. [PMID: 31541537 PMCID: PMC6806484 DOI: 10.1002/acm2.12712] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 07/18/2019] [Accepted: 08/07/2019] [Indexed: 12/20/2022] Open
Abstract
Postmastectomy radiation therapy is technically difficult and can be considered one of the most complex techniques concerning patient setup reproducibility. Slight patient setup variations — particularly when high‐conformal treatment techniques are used — can adversely affect the accuracy of the delivered dose and the patient outcome. This research aims to investigate the inter‐fraction setup variations occurring in two different scenarios of clinical practice: at the reference and at the current patient setups, when an image‐guided system is used or not used, respectively. The results were used with the secondary aim of assessing the robustness of the patient setup procedure in use. Forty eight patients treated with volumetric modulated arc and intensity modulated therapies were included in this study. EPID‐based in vivo dosimetry (IVD) was performed at the reference setup concomitantly with the weekly cone beam computed tomography acquisition and during the daily current setup. Three indices were analyzed: the ratio R between the reconstructed and planned isocenter doses, γ% and the mean value of γ from a transit dosimetry based on a two‐dimensional γ‐analysis of the electronic portal images using 5% and 5 mm as dose difference and distance to agreement gamma criteria; they were considered in tolerance if R was within 5%, γ% > 90% and γmean < 0.4. One thousand and sixteen EPID‐based IVD were analyzed and 6.3% resulted out of the tolerance level. Setup errors represented the main cause of this off tolerance with an occurrence rate of 72.2%. The percentage of results out of tolerance obtained at the current setup was three times greater (9.5% vs 3.1%) than the one obtained at the reference setup, indicating weaknesses in the setup procedure. This study highlights an EPID‐based IVD system's utility in the radiotherapy routine as part of the patient’s treatment quality controls and to optimize (or confirm) the performed setup procedures’ accuracy.
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Affiliation(s)
- Shengwei Kang
- Key Laboratory of Radiation Physics and Technology, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, China.,Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Jie Li
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Jiabao Ma
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Wei Zhang
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Xiongfei Liao
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Hou Qing
- Institute of Nuclear Science and Technology, Sichuan University, Chengdu, China
| | - Tingqiang Tan
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Xin Xin
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Bin Tang
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
| | - Angelo Piermattei
- UOC Fisica Sanitaria, Fondazione Policlinico Universitario Agostino Gemelli, Rome, Italy
| | - Lucia Clara Orlandini
- Department of Radiation Oncology, Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Chengdu, China
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Yedekci Y, Biltekin F, Ozyigit G. Feasibility study of an electronic portal imaging based in vivo dose verification system for prostate stereotactic body radiotherapy. Phys Med 2019; 64:204-209. [DOI: 10.1016/j.ejmp.2019.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 07/03/2019] [Accepted: 07/11/2019] [Indexed: 11/16/2022] Open
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Klausner G, Blais E, Martin C, Biau J, Jumeau R, Canova CH, Lyothier A, Slama Y, Jenny C, Chéa M, Zilli T, Miralbell R, Thariat J, Maingon P, Troussier I. De la construction du bunker à la prise en charge du patient : contrôles qualité des techniques modernes de radiothérapie. Cancer Radiother 2019; 23:248-254. [DOI: 10.1016/j.canrad.2018.07.142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/14/2018] [Accepted: 07/19/2018] [Indexed: 10/26/2022]
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Shi M, Myronakis M, Hu YH, Jacobson M, Lehmann M, Fueglistaller R, Huber P, Baturin P, Wang A, Ferguson D, Harris T, Morf D, Berbeco R. A novel method for fast image simulation of flat panel detectors. ACTA ACUST UNITED AC 2019; 64:095019. [DOI: 10.1088/1361-6560/ab12aa] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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39
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Hu YH, Shedlock D, Wang A, Rottmann J, Baturin P, Myronakis M, Huber P, Fueglistaller R, Shi M, Morf D, Star-Lack J, Berbeco RI. Characterizing a novel scintillating glass for application to megavoltage cone-beam computed tomography. Med Phys 2019; 46:1323-1330. [PMID: 30586163 DOI: 10.1002/mp.13355] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/10/2018] [Accepted: 12/16/2018] [Indexed: 01/19/2023] Open
Abstract
PURPOSE The purpose of this study was to evaluate the performance of a prototype electric portal imaging device (EPID) with a high detective quantum efficiency (DQE) scintillator, LKH-5. Specifically, image quality in context of both planar and megavoltage (MV) cone-beam computed tomography (CBCT) is analyzed. METHODS Planar image quality in terms of modulation transfer function (MTF), noise power spectrum (NPS), and DQE are measured and compared to an existing EPID (AS-1200) using the 6 MV beamline for a Varian TrueBeam linac. Imager performance is contextualized for three-dimensional (3D), MV-CBCT performance by measuring imager lag and analyzing the expected degradation of the DQE as a function of dose. Finally, comparisons between reconstructed images of the Catphan phantom in terms of qualitative quality and signal-difference-to-noise ratio (SDNR) are made for 6 MV images using both conventional and LKH-5 EPIDs as well as for the kilovoltage (kV) on-board imager (OBI). RESULTS Analysis of the NPS reveals linearity at all measured doses using the prototype LKH-5 detector. While the first zero of the MTF is much lower for the LKH-5 detector than the conventional EPID (0.6 cycles/mm vs 1.6 cycles/mm), the normalized NPS (NNPS) multiplied by total quanta (qNNPS) of the LKH-5 detector is roughly a factor of seven to eight times lower, yielding a DQE(0) of approximately 8%. First, second, and third frame lag were measured at approximately 23%, 5%, and 1%, respectively, although no noticeable image artifacts were apparent in reconstructed volumes. Analysis of low-dose performance reveals that DQE(0) remains at 80% of its maximum value at a dose as low as 7.5 × 10-6 MU. For a 400 projection technique, this represents a total scan dose of 0.0030 MU, suggesting that if imaging doses are increased to a value typical of kV-CBCT scans (~2.7 cGy), the LKH-5 detector will retain quantum noise limited performance. Finally, comparing Catphan scans, the prototype detector exhibits much lower image noise than the conventional EPID, resulting in improved small object representation. Furthermore, SDNR of H2 O and polystyrene cylinders improved from -1.95 and 2.94 to -15 and 18.7, respectively. CONCLUSIONS Imaging performance of the prototype LKH-5 detector was measured and analyzed for both planar and 3D contexts. Improving noise transfer of the detector results in concurrent improvement of DQE(0). For 3D imaging, temporal characteristics were adequate for artifact-free performance and at relevant doses, the detector retained quantum noise limited performance. Although quantitative MTF measurements suggest poorer resolution, small object representation of the prototype imager is qualitatively improved over the conventional detector due to the measured reduction in noise.
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Affiliation(s)
- Yue-Houng Hu
- Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
| | | | - Adam Wang
- Varian Medical Systems, Palo Alto, CA, 94304-1030, USA
| | - Joerg Rottmann
- Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Paul Baturin
- Varian Medical Systems, Palo Alto, CA, 94304-1030, USA
| | - Marios Myronakis
- Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Pascal Huber
- Varian Medical Systems, CH-5405, Baden-Dattwil, Switzerland
| | | | - Mengying Shi
- University of Massachusetts Lowell, Lowell, MA, 01854, USA
| | - Daniel Morf
- Varian Medical Systems, CH-5405, Baden-Dattwil, Switzerland
| | | | - Ross I Berbeco
- Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women's Hospital, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
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Anvari A, Poirier Y, Sawant A. Kilovoltage transit and exit dosimetry for a small animal image-guided radiotherapy system using built-in EPID. Med Phys 2018; 45:4642-4651. [DOI: 10.1002/mp.13134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 08/08/2018] [Accepted: 08/08/2018] [Indexed: 11/06/2022] Open
Affiliation(s)
- Akbar Anvari
- Department of Radiation Oncology; University of Maryland School of Medicine; Baltimore MD 21201 USA
| | - Yannick Poirier
- Department of Radiation Oncology; University of Maryland School of Medicine; Baltimore MD 21201 USA
| | - Amit Sawant
- Department of Radiation Oncology; University of Maryland School of Medicine; Baltimore MD 21201 USA
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Moghadam SE, Nasseri S, Seyedi SS, Gholamhosseinian H, Momennezhad M. Evaluation of application of EPID for rapid QC testing of linear accelerator. Rep Pract Oncol Radiother 2018; 23:369-377. [PMID: 30127677 DOI: 10.1016/j.rpor.2018.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 05/15/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022] Open
Abstract
Aim Evaluation of application of EPID for rapid QC testing of linear accelerator. Background Quality control of a linear accelerator device is a time and energy intensive process. In this study, attempts have been made to perform the linear accelerator quality control using electronic portal imaging device (EPID), which is mounted on most accelerators. Materials and methods First, quality control and dosimetry parameters of the device were determined and measured based on standard protocols to ensure full calibration of the accelerator. Then, various features of EPID including spatial resolution and contrast resolution, the effect of buildup region, dose response and image uniformity were evaluated. In the next step, consistent with the parameters of linear accelerator quality control including field size, field flatness and symmetry, the light field coincidence with X-ray field, mechanical stability and multileaf collimator position accuracy test, the output images of device were obtained.After feeding images to the MATLAB software, their pixel content was analyzed. All measurements of the three photon beams were repeated three times. Results The EPID image had a desirable resolution, contrast and uniformity and displayed high sensitivity to dose changes with linear dose response. Seven qualitative parameters of the linear accelerator were then controlled by EPID. Conclusions The results of the linear accelerator quality control using the EPID were consistent with practice. Quality control using the EPID was more convenient and faster than conventional methods.
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Affiliation(s)
- Shahla Ebrahimi Moghadam
- Department of Medical Physics, Faculty of Medicine, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Shahrokh Nasseri
- Department of Medical Physics, Faculty of Medicine, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyedeh Somayeh Seyedi
- Department of Medical Physics, Faculty of Medicine, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid Gholamhosseinian
- Department of Medical Physics, Faculty of Medicine, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Momennezhad
- Department of Medical Physics, Faculty of Medicine, Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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Shi M, Myronakis M, Hu YH, Morf D, Rottmann J, Berbeco R. A Monte Carlo study of the impact of phosphor optical properties on EPID imaging performance. Phys Med Biol 2018; 63:165013. [PMID: 30051879 DOI: 10.1088/1361-6560/aad647] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We have developed a Monte Carlo computational model of a clinically employed electronic portal imaging device (EPID), and demonstrated the impact of phosphor optical properties on the imaging performance. The EPID model was built with Geant4 application for tomographic emission. Both radiative and optical transport were included in the model. Modulation transfer function (MTF), normalized noise-power spectrum times the incident x-ray fluence (qNNPS), and detective quantum efficiency (DQE) were calculated for simulated and measured data, and their agreement was quantified by the normalized root-mean-square error (NRMSE). MTF was computed using a 100 µm wide slit tilted by 1.5° and qNNPS was estimated using the Fujita-Lubberts-Swank method. DQE was calculated from MTF and qNNPS data. The NRMSE value was 0.0467 for MTF, 0.0217 for qNNPS, and 0.0885 for DQE, showing good agreement between measurement and simulation. Five major optical properties, phosphor grain size, phosphor thickness, phosphor refractive index, binder refractive index, and packing ratio were tested for their influence on the qNNPS, MTF, and DQE(0) of the model. Generally, the effect on the qNNPS is greater than MTF, and no impact on DQE(0), except from phosphor thickness, was observed. Multiple applications, such as imager design optimization and investigations of the dosimetric performance, are expected to benefit from the validated model.
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Affiliation(s)
- Mengying Shi
- Medical Physics Program, Department of Physics and Applied Physics, University of Massachusetts Lowell, Lowell, MA 01854, United States of America. Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, United States of America
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Hu YH, Fueglistaller R, Myronakis M, Rottmann J, Wang A, Shedlock D, Morf D, Baturin P, Huber P, Star-Lack J, Berbeco R. Physics considerations in MV-CBCT multi-layer imager design. Phys Med Biol 2018; 63:125016. [PMID: 29846180 DOI: 10.1088/1361-6560/aac8c6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Megavoltage (MV) cone-beam computed tomography (CBCT) using an electronic portal imaging (EPID) offers advantageous features, including 3D mapping, treatment beam registration, high-z artifact suppression, and direct radiation dose calculation. Adoption has been slowed by image quality limitations and concerns about imaging dose. Developments in imager design, including pixelated scintillators, structured phosphors, inexpensive scintillation materials, and multi-layer imager (MLI) architecture have been explored to improve EPID image quality and reduce imaging dose. The present study employs a hybrid Monte Carlo and linear systems model to determine the effect of detector design elements, such as multi-layer architecture and scintillation materials. We follow metrics of image quality including modulation transfer function (MTF) and noise power spectrum (NPS) from projection images to 3D reconstructions to in-plane slices and apply a task based figure-of-merit, the ideal observer signal-to-noise ratio (d') to determine the effect of detector design on object detectability. Generally, detectability was limited by detector noise performance. Deploying an MLI imager with a single scintillation material for all layers yields improvement in noise performance and d' linear with the number of layers. In general, improving x-ray absorption using thicker scintillators results in improved DQE(0). However, if light yield is low, performance will be affected by electronic noise at relatively high doses, resulting in rapid image quality degradation. Maximizing image quality in a heterogenous MLI detector (i.e. multiple different scintillation materials) is most affected by limiting total noise. However, while a second-order effect, maximizing total spatial resolution of the MLI detector is a balance between the intensity contribution of each layer against its individual MTF. So, while a thinner scintillator may yield a maximal individual-layer MTF, its quantum efficiency will be relatively low in comparison to a thicker scintillator and thus, intensity contribution may be insufficient to noticeably improve the total detector MTF.
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Affiliation(s)
- Yue-Houng Hu
- Department of Radiation Oncology, Division of Medical Physics and Biophysics, Brigham and Women's Hospital, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, United States of America
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Setup in a clinical workflow and impact on radiotherapy routine of an in vivo dosimetry procedure with an electronic portal imaging device. PLoS One 2018; 13:e0192686. [PMID: 29432473 PMCID: PMC5809064 DOI: 10.1371/journal.pone.0192686] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 01/29/2018] [Indexed: 12/21/2022] Open
Abstract
High conformal techniques such as intensity-modulated radiation therapy and volumetric-modulated arc therapy are widely used in overloaded radiotherapy departments. In vivo dosimetric screening is essential in this environment to avoid important dosimetric errors. This work examines the feasibility of introducing in vivo dosimetry (IVD) checks in a radiotherapy routine. The causes of dosimetric disagreements between delivered and planned treatments were identified and corrected during the course of treatment. The efficiency of the corrections performed and the added workload needed for the entire procedure were evaluated. The IVD procedure was based on an electronic portal imaging device. A total of 3682 IVD tests were performed for 147 patients who underwent head and neck, abdomen, pelvis, breast, and thorax radiotherapy treatments. Two types of indices were evaluated and used to determine if the IVD tests were within tolerance levels: the ratio R between the reconstructed and planned isocentre doses and a transit dosimetry based on the γ-analysis of the electronic portal images. The causes of test outside tolerance level were investigated and corrected and IVD test was repeated during subsequent fraction. The time needed for each step of the IVD procedure was registered. Pelvis, abdomen, and head and neck treatments had 10% of tests out of tolerance whereas breast and thorax treatments accounted for up to 25%. The patient setup was the main cause of 90% of the IVD tests out of tolerance and the remaining 10% was due to patient morphological changes. An average time of 42 min per day was sufficient to monitor a daily workload of 60 patients in treatment. This work shows that IVD performed with an electronic portal imaging device is feasible in an overloaded department and enables the timely realignment of the treatment quality indices in order to achieve a patient’s final treatment compliant with the one prescribed.
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Held M, Cheung J, Perez Andujar A, Husson F, Morin O. Commissioning and Evaluation of an Electronic Portal Imaging Device-Based In-Vivo Dosimetry Software. Cureus 2018; 10:e2139. [PMID: 29632749 PMCID: PMC5880591 DOI: 10.7759/cureus.2139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This study reports on our experience with the in-vivo dose verification software, EPIgray® (DOSIsoft, Cachan, France). After the initial commissioning process, clinical experiments on phantom treatments were evaluated to assess the level of accuracy of the electronic portal imaging device (EPID) based in-vivo dose verification. EPIgray was commissioned based on the company’s instructions. This involved ion chamber measurements and portal imaging of solid water blocks of various thicknesses between 5 and 35 cm. Field sizes varied between 2 x 2 cm2 and 20 x 20 cm2. The determined conversion factors were adjusted through an additional iterative process using treatment planning system calculations. Subsequently, evaluation was performed using treatment plans of single and opposed beams, as well as intensity modulated radiotherapy (IMRT) plans, based on recommendations from the task group report TG-119 to test for dose reconstruction accuracy. All tests were performed using blocks of solid water slabs as a phantom. For single square fields, the dose at isocenter was reconstructed within 3% accuracy in EPIgray compared to the treatment planning system dose. Similarly, the relative deviation of the total dose was accurately reconstructed within 3% for all IMRT plans with points placed inside a high-dose region near the isocenter. Predictions became less accurate than < 5% when the evaluation point was outside the treatment target. Dose at points 5 cm or more away from the isocenter or within an avoidance structure was reconstructed less reliably. EPIgray formalism accuracy is adequate for an efficient error detection system with verifications performed in high-dose volumes. It provides immediate intra-fractional feedback on the delivery of treatment plans without affecting the treatment beam. Besides the EPID, no additional hardware is required. The software evaluates local point dose measurements to verify treatment plan delivery and patient positioning within 5% accuracy, depending on the placement of evaluation points.
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Affiliation(s)
- Mareike Held
- Radiation Oncology, University of California San Francisco
| | - Joey Cheung
- Radiation Oncology, University of California San Francisco
| | | | | | - Olivier Morin
- Radiation Oncology, University of California San Francisco
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Falco MD, Giancaterino S, De Nicola A, Adorante N, De Lorenzo RG, Di Tommaso M, Vinciguerra A, Trignani M, Perrotti F, Allajbej A, Fidanzio A, Greco F, Grusio M, Genovesi D, Piermattei A. A Feasibility Study for in vivo Dosimetry Procedure in Routine Clinical Practice. Technol Cancer Res Treat 2018; 17:1533033818779201. [PMID: 29871570 PMCID: PMC5992805 DOI: 10.1177/1533033818779201] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Purpose: The aim of the in vivo dosimetry, during the fractionated radiation therapy, is the verification of the correct dose delivery to patient. Nowadays, in vivo dosimetry procedures for photon beams are based on the use of the electronic portal imaging device and dedicated software to elaborate electronic portal imaging device images. Methods: In total, 8474 in vivo dosimetry tests were carried out for 386 patients treated with 3-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and volumetric modulated arc therapy techniques, using the SOFTDISO. SOFTDISO is a dedicated software that uses electronic portal imaging device images in order to (1) calculate the R index, that is, the ratio between daily reconstructed dose and the planned one at isocenter and (2) perform a γ-like analysis between the signals, S, of a reference electronic portal imaging device image and that obtained in a daily fraction. It supplies 2 indexes, the percentage γ% of points with γ < 1 and the mean γ value, γmean. In γ-like analysis, the pass criteria for the signals agreement ΔS% and distance to agreement Δd have been selected based on the clinical experience and technology used. The adopted tolerance levels for the 3 indexes were fixed in 0.95 ≤ R ≤ 1.05, γ% ≥ 90%, and γmean ≤ 0.5. Results: The results of R ratio, γ-like, and a visual inspection of these data reported on a monitor screen permitted to individuate 2 classes of errors (1) class 1 that included errors due to inadequate standard quality controls and (2) class 2, due to patient morphological changes. Depending on the technique and anatomical site, a maximum of 18% of tests had at least 1 index out of tolerance; once removed the causes of class-1 errors, almost all patients (except patients with 4 lung and 2 breast cancer treated with 3-dimensional conformal radiotherapy) presented mean indexes values (R¯, γ¯%, and γ¯mean
) within tolerance at the end of treatment course. Class-2 errors were found in some patients. Conclusions: The in vivo dosimetry procedure with SOFTDISO resulted easily implementable, able to individuate errors with a limited workload.
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Affiliation(s)
- Maria D Falco
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Stefano Giancaterino
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Andrea De Nicola
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Nico Adorante
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Ramon Gimenez De Lorenzo
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Monica Di Tommaso
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Annamaria Vinciguerra
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Marianna Trignani
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Francesca Perrotti
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Albina Allajbej
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Andrea Fidanzio
- 2 Unità Operativa di Fisica Sanitaria; Fondazione Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Francesca Greco
- 2 Unità Operativa di Fisica Sanitaria; Fondazione Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Mattia Grusio
- 2 Unità Operativa di Fisica Sanitaria; Fondazione Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Roma, Italy
| | - Domenico Genovesi
- 1 Department of Radiation Oncology "G. D'Annunzio", University of Chieti, SS. Annunziata Hospital, Chieti, Italy
| | - Angelo Piermattei
- 2 Unità Operativa di Fisica Sanitaria; Fondazione Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Roma, Italy
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McCurdy BM, McCowan PM. In vivo dosimetry for lung radiotherapy including SBRT. Phys Med 2017; 44:123-130. [DOI: 10.1016/j.ejmp.2017.05.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/20/2017] [Accepted: 05/22/2017] [Indexed: 12/18/2022] Open
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Abstract
PURPOSE To improve patient safety and treatment quality, verification of dose delivery in radiotherapy is desirable. We present a simple, easy-to-implement, open-source method for in vivo planar dosimetry of conformal radiotherapy by electronic portal imaging device (EPID). METHODS Correlation ratios, which relate dose in the mid-depth of slab phantoms to transit EPID signal, were determined for multiple phantom thicknesses and field sizes. Off-axis dose is corrected for by means of model-based convolution. We tested efficacy of dose reconstruction through measurements with off-reference values of attenuator thickness, field size, and monitor units. We quantified the dose calculation error in the presence of thickness changes to simulate anatomical or setup variations. An example of dose calculation on patient data is provided. RESULTS With varying phantom thickness, field size, and monitor units, dose reconstruction was almost always within 3% of planned dose. In the presence of thickness changes from planning CT, the dose discrepancy is exaggerated by up to approximately 1.5% for 1 cm changes upstream of the isocenter plane and 4% for 1 cm changes downstream. CONCLUSION Our novel electronic portal imaging device in vivo dosimetry allows clinically accurate 2-dimensional reconstruction of dose inside a phantom/patient at isocenter depth. Due to its simplicity, commissioning can be performed in a few hours per energy and may be modified to the user's needs. It may provide useful dose delivery information to detect harmful errors, guide adaptive radiotherapy, and assure quality of treatment.
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Affiliation(s)
- Stefano Peca
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada
| | - Derek Wilson Brown
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Department of Radiation Medicine and Applied Sciences, Moores Cancer Center, UC San Diego, La Jolla, CA, USA
| | - Wendy Lani Smith
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, Canada.,Department of Medical Physics, Tom Baker Cancer Centre, Calgary, AB, Canada.,Department of Radiation Oncology, University of Calgary, Calgary, AB, Canada
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Putha SK, Saxena PU, Banerjee S, Srinivas C, Vadhiraja BM, Ravichandran R, Joan M, Pai KD. On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator. J Med Phys 2017; 41:224-233. [PMID: 28144114 PMCID: PMC5228045 DOI: 10.4103/0971-6203.195186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (St) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. Sts were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (Diso,TPS), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (Diso,Transit) from the measured Sts. A locally fabricated pelvic phantom validated the estimations of Diso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The Diso,Transit agreement with Diso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is −1.37% ±2.03% (n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.
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Affiliation(s)
- Suman Kumar Putha
- Department of Radiotherapy and Oncology, Kasturba Medical College Hospital (An Associated Teaching Hospital of Manipal University), Mangalore, Karnataka, India
| | - P U Saxena
- Department of Radiotherapy and Oncology, Kasturba Medical College Hospital (An Associated Teaching Hospital of Manipal University), Mangalore, Karnataka, India
| | - S Banerjee
- Department of Radiotherapy and Oncology, Kasturba Medical College Hospital (An Associated Teaching Hospital of Manipal University), Mangalore, Karnataka, India
| | - Challapalli Srinivas
- Department of Radiotherapy and Oncology, Kasturba Medical College Hospital (An Associated Teaching Hospital of Manipal University), Mangalore, Karnataka, India
| | - B M Vadhiraja
- Department of Radiation Oncology, Manipal Hospital, Bengaluru, Karnataka, India
| | - Ramamoorthy Ravichandran
- Department of Medical Radiation Physics, School of Allied Health Sciences, Manipal University, Manipal, Karnataka, India
| | - Mary Joan
- Department of Radiological Physics, SMS Medical College, Jaipur, Rajasthan, India
| | - K Dinesh Pai
- Department of Radiotherapy and Oncology, Kasturba Medical College Hospital (An Associated Teaching Hospital of Manipal University), Mangalore, Karnataka, India
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McCowan PM, Asuni G, Van Uytven E, VanBeek T, McCurdy BMC, Loewen SK, Ahmed N, Bashir B, Butler JB, Chowdhury A, Dubey A, Leylek A, Nashed M. Clinical Implementation of a Model-Based In Vivo Dose Verification System for Stereotactic Body Radiation Therapy-Volumetric Modulated Arc Therapy Treatments Using the Electronic Portal Imaging Device. Int J Radiat Oncol Biol Phys 2017; 97:1077-1084. [PMID: 28332992 DOI: 10.1016/j.ijrobp.2017.01.227] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/27/2016] [Accepted: 01/25/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE To report findings from an in vivo dosimetry program implemented for all stereotactic body radiation therapy patients over a 31-month period and discuss the value and challenges of utilizing in vivo electronic portal imaging device (EPID) dosimetry clinically. METHODS AND MATERIALS From December 2013 to July 2016, 117 stereotactic body radiation therapy-volumetric modulated arc therapy patients (100 lung, 15 spine, and 2 liver) underwent 602 EPID-based in vivo dose verification events. A developed model-based dose reconstruction algorithm calculates the 3-dimensional dose distribution to the patient by back-projecting the primary fluence measured by the EPID during treatment. The EPID frame-averaging was optimized in June 2015. For each treatment, a 3%/3-mm γ comparison between our EPID-derived dose and the Eclipse AcurosXB-predicted dose to the planning target volume (PTV) and the ≥20% isodose volume were performed. Alert levels were defined as γ pass rates <85% (lung and liver) and <80% (spine). Investigations were carried out for all fractions exceeding the alert level and were classified as follows: EPID-related, algorithmic, patient setup, anatomic change, or unknown/unidentified errors. RESULTS The percentages of fractions exceeding the alert levels were 22.6% for lung before frame-average optimization and 8.0% for lung, 20.0% for spine, and 10.0% for liver after frame-average optimization. Overall, mean (± standard deviation) planning target volume γ pass rates were 90.7% ± 9.2%, 87.0% ± 9.3%, and 91.2% ± 3.4% for the lung, spine, and liver patients, respectively. CONCLUSIONS Results from the clinical implementation of our model-based in vivo dose verification method using on-treatment EPID images is reported. The method is demonstrated to be valuable for routine clinical use for verifying delivered dose as well as for detecting errors.
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Affiliation(s)
- Peter M McCowan
- Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba, Canada.
| | - Ganiyu Asuni
- Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba, Canada
| | - Eric Van Uytven
- Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba, Canada; Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Timothy VanBeek
- Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba, Canada
| | - Boyd M C McCurdy
- Medical Physics Department, CancerCare Manitoba, Winnipeg, Manitoba, Canada; Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Radiology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Shaun K Loewen
- Department of Oncology, University of Calgary, Calgary, Alberta, Canada
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