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Karger CP, Elter A, Dorsch S, Mann P, Pappas E, Oldham M. Validation of complex radiotherapy techniques using polymer gel dosimetry. Phys Med Biol 2024; 69:06TR01. [PMID: 38330494 DOI: 10.1088/1361-6560/ad278f] [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: 02/06/2023] [Accepted: 02/08/2024] [Indexed: 02/10/2024]
Abstract
Modern radiotherapy delivers highly conformal dose distributions to irregularly shaped target volumes while sparing the surrounding normal tissue. Due to the complex planning and delivery techniques, dose verification and validation of the whole treatment workflow by end-to-end tests became much more important and polymer gel dosimeters are one of the few possibilities to capture the delivered dose distribution in 3D. The basic principles and formulations of gel dosimetry and its evaluation methods are described and the available studies validating device-specific geometrical parameters as well as the dose delivery by advanced radiotherapy techniques, such as 3D-CRT/IMRT and stereotactic radiosurgery treatments, the treatment of moving targets, online-adaptive magnetic resonance-guided radiotherapy as well as proton and ion beam treatments, are reviewed. The present status and limitations as well as future challenges of polymer gel dosimetry for the validation of complex radiotherapy techniques are discussed.
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Affiliation(s)
- Christian P Karger
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Alina Elter
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
- Department of Radiation Oncology, University Hospital Heidelberg, Im Neuenheimer Feld 400, D-69120 Heidelberg, Germany
| | - Stefan Dorsch
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Philipp Mann
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
- National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Evangelos Pappas
- Radiology & Radiotherapy Sector, Department of Biomedical Sciences, University of West Attica, Athens, Greece
| | - Mark Oldham
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, United States of America
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Udee N, Commukchik S, Khamfongkhruea C, Kaewlek T, Chusin T, Yabsantia S. Delta 4-based Dosimetric Error Detection in Volumetric-modulated Arc Therapy: Clinical Significance and Implications. J Med Phys 2024; 49:56-63. [PMID: 38828070 PMCID: PMC11141741 DOI: 10.4103/jmp.jmp_140_23] [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: 10/10/2023] [Revised: 12/01/2023] [Accepted: 12/01/2023] [Indexed: 06/05/2024] Open
Abstract
Background Volumetric-modulated arc therapy (VMAT) is an efficient method of administering intensity-modulated radiotherapy beams. The Delta4 device was employed to examine patient data. Aims and Objectives The utility of the Delta4 device in identifying errors for patient-specific quality assurance of VMAT plans was studied in this research. Materials and Methods Intentional errors were purposely created in the collimator rotation, gantry rotation, multileaf collimator (MLC) position displacement, and increase in the number of monitor units (MU). Results The results show that when the characteristics of the treatment plans were changed, the gamma passing rate (GPR) decreased. The largest percentage of erroneous detection was seen in the increasing number of MU, with a GPR ranging from 41 to 92. Gamma analysis was used to compare the dose distributions of the original and intentional error designs using the 2%/2 mm criteria. The percentage of dose errors (DEs) in the dose-volume histogram (DVH) was also analyzed, and the statistical association was assessed using logistic regression. A modest association (Pearson's R-values: 0.12-0.67) was seen between the DE and GPR in all intentional plans. The findings indicated a moderate association between DVH and GPR. The data reveal that Delta4 is effective in detecting mistakes in treatment regimens for head-and-neck cancer as well as lung cancer. Conclusion The study results also imply that Delta4 can detect errors in VMAT plans, depending on the details of the defects and the treatment plans employed.
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Affiliation(s)
- Nuntawat Udee
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Supada Commukchik
- Department of Radiation Therapy, Udon Thani Cancer Hospital, Udon Thani, Thailand
| | - Chirasak Khamfongkhruea
- Department of Radiation Therapy, Radiation Oncology Unit, Chulabhorn Hospital, Bangkok, Thailand
| | - Titipong Kaewlek
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Thunyarat Chusin
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
| | - Sumalee Yabsantia
- Department of Radiological Technology, Faculty of Allied Health Sciences, Naresuan University, Phitsanulok, Thailand
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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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Tan HQ, Koh CWY, Tan LKR, Lew KS, Chua CGA, Ang KW, Lee JCL, Park SY. A transit portal dosimetry method for respiratory gating quality assurance with a dynamic 3D printed tumor phantom. J Appl Clin Med Phys 2022; 23:e13560. [PMID: 35147283 PMCID: PMC9121038 DOI: 10.1002/acm2.13560] [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: 07/27/2021] [Revised: 12/27/2021] [Accepted: 01/29/2022] [Indexed: 11/21/2022] Open
Abstract
Backgrounds Respiratory gating is one of the motion management techniques that is used to deliver radiation dose to a tumor at a specific position under free breathing. However, due to the dynamic feedback process of this approach, regular equipment quality assurance (QA) and patient‐specific QA checks need to be performed. This work proposes a new QA methodology using electronic portal imaging detector (EPID) to determine the target localization accuracy of phase gating. Methods QA tools comprising 3D printed spherical tumor phantoms, programmable stages, and an EPID detector are characterized and assembled. Algorithms for predicting portal dose (PD) through moving phantoms are developed and verified using gamma analysis for two spherical tumor phantoms (2 cm and 4 cm), two different 6 MV volumetric modulated arc therapy plans, and two different gating windows (30%–70% and 40%–60%). Comparison between the two gating windows is then performed using the Wilcoxon signed‐rank test. An optimizer routine, which is used to determine the optimal window, based on maximal gamma passing rate (GPR), was applied to an actual breathing curve and breathing plan. This was done to ascertain if our method yielded a similar result with the actual gating window. Results High GPRs of more than 97% and 91% were observed when comparing the predicted PD with the measured PD in moving phantom at 2 mm/2% and 1 mm/1% levels, respectively. Analysis of gamma heatmaps shows an excellent agreement with the tumor phantom. The GPR of 40%–60% PD was significantly lower than that of the 30%–70% PD at the 1 mm/1% level (p = 0.0064). At the 2 mm/2% level, no significant differences were observed. The optimizer routine could accurately predict the center of the gating window to within a 10% range. Conclusion We have successfully performed and verified a new method for QA with the use of a moving phantom with EPID for phase gating with real‐time position management.
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Affiliation(s)
- Hong Qi Tan
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - Calvin Wei Yang Koh
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - Lloyd Kuan Rui Tan
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - Kah Seng Lew
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | | | - Khong Wei Ang
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore
| | - James Cheow Lei Lee
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore.,Division of Physics and Applied Physics, Nanyang Technological University, Singapore, Singapore
| | - Sung Yong Park
- Division of Radiation Oncology, National Cancer Centre, Singapore, Singapore.,Oncology Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore
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Piffer S, Casati M, Marrazzo L, Arilli C, Calusi S, Desideri I, Fusi F, Pallotta S, Talamonti C. Validation of a secondary dose check tool against Monte Carlo and analytical clinical dose calculation algorithms in VMAT. J Appl Clin Med Phys 2021; 22:52-62. [PMID: 33735491 PMCID: PMC8035572 DOI: 10.1002/acm2.13209] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Patient-specific quality assurance (QA) is very important in radiotherapy, especially for patients with highly conformed treatment plans like VMAT plans. Traditional QA protocols for these plans are time-consuming reducing considerably the time available for patient treatments. In this work, a new MC-based secondary dose check software (SciMoCa) is evaluated and benchmarked against well-established TPS (Monaco and Pinnacle3 ) by means of treatment plans and dose measurements. METHODS Fifty VMAT plans have been computed using same calculation parameters with SciMoCa and the two primary TPSs. Plans were validated with measurements performed with a 3D diode detector (ArcCHECK) by translating patient plans to phantom geometry. Calculation accuracy was assessed by measuring point dose differences and gamma passing rates (GPR) from a 3D gamma analysis with 3%-2 mm criteria. Comparison between SciMoCa and primary TPS calculations was made using the same estimators and using both patient and phantom geometry plans. RESULTS TPS and SciMoCa calculations were found to be in very good agreement with validation measurements with average point dose differences of 0.7 ± 1.7% and -0.2 ± 1.6% for SciMoCa and two TPSs, respectively. Comparison between SciMoCa calculations and the two primary TPS plans did not show any statistically significant difference with average point dose differences compatible with zero within error for both patient and phantom geometry plans and GPR (98.0 ± 3.0% and 99.0 ± 3.0% respectively) well in excess of the typical 95 % clinical tolerance threshold. CONCLUSION This work presents results obtained with a significantly larger sample than other similar analyses and, to the authors' knowledge, compares SciMoCa with a MC-based TPS for the first time. Results show that a MC-based secondary patient-specific QA is a clinically viable, reliable, and promising technique, that potentially allows significant time saving that can be used for patient treatment and a per-plan basis QA that effectively complements traditional commissioning and calibration protocols.
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Affiliation(s)
- Stefano Piffer
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
- National Institute of Nuclear Physics (INFN)FlorenceItaly
| | - Marta Casati
- Department of Medical PhysicsCareggi University HospitalFlorenceItaly
| | - Livia Marrazzo
- Department of Medical PhysicsCareggi University HospitalFlorenceItaly
| | - Chiara Arilli
- Department of Medical PhysicsCareggi University HospitalFlorenceItaly
| | - Silvia Calusi
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Isacco Desideri
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Franco Fusi
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
| | - Stefania Pallotta
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
- National Institute of Nuclear Physics (INFN)FlorenceItaly
- Department of Medical PhysicsCareggi University HospitalFlorenceItaly
| | - Cinzia Talamonti
- Department of Experimental and Clinical Biomedical SciencesUniversity of FlorenceFlorenceItaly
- National Institute of Nuclear Physics (INFN)FlorenceItaly
- Department of Medical PhysicsCareggi University HospitalFlorenceItaly
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Chendi A, Botti A, Orlandi M, Sghedoni R, Iori M, Cagni E. EPID-based 3D dosimetry for pre-treatment FFF VMAT stereotactic body radiotherapy plan verification using dosimetry Check TM. Phys Med 2021; 81:227-236. [PMID: 33485140 DOI: 10.1016/j.ejmp.2020.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 10/22/2022] Open
Abstract
PURPOSE The software Dosimetry Check (DC) reconstructs the 3D dose distribution on CT images data set by using EPID measured signal. This study aimed to evaluate DC for stereotactic body radiotherapy (SBRT) with unflattened photon beams (FFF) for dosimetric independent plan verification in pre-treatment modality. METHODS DC v.4.1 was configured for Varian TrueBeam STx FFF beams equipped with EPID aS-1200. The DC FFF models were tested using arc open fields (from 1×1 cm2 to 15×15 cm2) and VMAT (Volumetric Modulated Arc Therapy) SBRT plans on phantom and patient CTs. DC dose distributions (DDC) were compared with that calculated by Eclipse with Acuros XB algorithm (DAXB) and one measured by Octavius 1000 SRS detector (DOCT). All differences were quantified in terms of the local 3D gamma passing rate (%GP), DVH and point dose differences. RESULTS DC was configured for FFF VMAT using an appropriate correction procedure. %GP2%2mm (mean±standard deviation) of DOCT-DDC was 96.3±2.7% for open fields whereas it was 90.1±5.9% for plans on homogeneous phantom CT. However, average %GP3%3mm of DAXB-DDC was 95.0±4.1 for treatments on patient CT. The fraction of plans passing the %GP3%3mm DQA tolerance level [10% (50%) of maximum dose threshold] were 20/20 (14/20) and 18/20 (16/20) for OCT on phantom CT and DC on patient CT, respectively. CONCLUSIONS DC characterization for FFF beams was performed. For stereotactic VMAT plan verifications DC showed good agreement with TPS whereas underlined discrepancies with Octavius in the high dose regions. A customized tolerance level is required for EPID-based VMAT FFF pre-treatment verification when DC system is applied.
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Affiliation(s)
- Agnese Chendi
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy; Postgraduate School in Medical Physics, University of Bologna, Bologna, Italy.
| | - Andrea Botti
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Matteo Orlandi
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Roberto Sghedoni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Mauro Iori
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | - Elisabetta Cagni
- Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy; School of Engineering, Cardiff University, Cardiff, UK
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Jeong S, Yoon M, Chung K, Ahn SH, Lee B, Seo J. Clinical application of a gantry-attachable plastic scintillating plate dosimetry system in pencil beam scanning proton therapy beam monitoring. Phys Med 2020; 77:181-186. [DOI: 10.1016/j.ejmp.2020.08.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/24/2020] [Accepted: 08/19/2020] [Indexed: 12/14/2022] Open
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Olaciregui‐Ruiz I, Vivas‐Maiques B, Kaas J, Perik T, Wittkamper F, Mijnheer B, Mans A. Transit and non-transit 3D EPID dosimetry versus detector arrays for patient specific QA. J Appl Clin Med Phys 2019; 20:79-90. [PMID: 31083776 PMCID: PMC6560233 DOI: 10.1002/acm2.12610] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 01/09/2023] Open
Abstract
PURPOSE Despite their availability and simplicity of use, Electronic Portal Imaging Devices (EPIDs) have not yet replaced detector arrays for patient specific QA in 3D. The purpose of this study is to perform a large scale dosimetric evaluation of transit and non-transit EPID dosimetry against absolute dose measurements in 3D. METHODS After evaluating basic dosimetric characteristics of the EPID and two detector arrays (Octavius 1500 and Octavius 1000SRS ), 3D dose distributions for 68 VMAT arcs, and 10 IMRT plans were reconstructed within the same phantom geometry using transit EPID dosimetry, non-transit EPID dosimetry, and the Octavius 4D system. The reconstructed 3D dose distributions were directly compared by γ-analysis (2L2 = 2% local/2 mm and 3G2 = 3% global/2 mm, 50% isodose) and by the percentage difference in median dose to the high dose volume (%∆HDVD 50 ). RESULTS Regarding dose rate dependency, dose linearity, and field size dependence, the agreement between EPID dosimetry and the two detector arrays was found to be within 1.0%. In the 2L2 γ-comparison with Octavius 4D dose distributions, the average γ-pass rate value was 92.2 ± 5.2%(1SD) and 94.1 ± 4.3%(1SD) for transit and non-transit EPID dosimetry, respectively. 3G2 γ-pass rate values were higher than 95% in 150/156 cases. %∆HDVD 50 values were within 2% in 134/156 cases and within 3% in 155/156 cases. With regard to the clinical classification of alerts, 97.5% of the treatments were equally classified by EPID dosimetry and Octavius 4D. CONCLUSION Transit and non-transit EPID dosimetry are equivalent in dosimetric terms to conventional detector arrays for patient specific QA. Non-transit 3D EPID dosimetry can be readily used for pre-treatment patient specific QA of IMRT and VMAT, eliminating the need of phantom positioning.
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Affiliation(s)
- Igor Olaciregui‐Ruiz
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
| | - Begoña Vivas‐Maiques
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
| | - Jochem Kaas
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
| | - Thijs Perik
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
| | - Frits Wittkamper
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
| | - Ben Mijnheer
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
| | - Anton Mans
- Department of Radiation OncologyThe Netherlands Cancer Institute – Antoni van LeeuwenhoekAmsterdamThe Netherlands
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Chun M, Joon An H, Kwon O, Oh DH, Park JM, Kim JI. Impact of plan parameters and modulation indices on patient-specific QA results for standard and stereotactic VMAT. Phys Med 2019; 62:83-94. [PMID: 31153402 DOI: 10.1016/j.ejmp.2019.05.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/03/2019] [Accepted: 05/04/2019] [Indexed: 12/30/2022] Open
Abstract
PURPOSE To demonstrate the impact of modulation indices and plan parameters on the gamma passing rates (GPR) of patient-specific quality assurance of standard and stereotactic volumetric modulated arc therapy (VMAT) plans. METHODS A total of 758 patients' QA plans were utilized, including standard VMAT plans with Trilogy (n = 87, group A) and TreuBeam STx (n = 332, group B), and 339 stereotactic VMAT plans with TrueBeam STx (group C). Modulation indices were obtained considering the speed and acceleration of the multileaf collimator (MLC) (MIs, MIa), and MLC, gantry speed, and dose rate changes (MIt). The mean aperture size (MA), monitor unit (MU), and amount of jaw tracking (%JT) were acquired. Gamma analysis was performed with 2 mm/2% and 1 mm/2% for the standard and stereotactic VMAT plans, respectively. Statistical analyses were performed to investigate the correlation between modulation index/plan parameters and GPR. RESULTS Spearman's rank correlation to GPRs with MIs, MIa, and MIt, were -0.44, -0.45, and -0.46 for group A; -0.39, -0.37, and -0.38 for group B; and -0.04, -0.11, and -0.10 for group C, respectively. While MU and MA showed significant correlations in all groups, %JT showed a significant correlation only with stereotactic VMAT plans. The most influential parameter combinations were MU-MA (rs = 0.50), MIs-%JT (rs = 0.43), and MU-%JT (rs = 0.38) for groups A, B, and C, respectively. CONCLUSIONS MLC modulation mostly affected the GPR in the delivery of standard VMAT plans, while MU and %JT showed more importance in stereotactic VMAT plans.
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Affiliation(s)
- Minsoo Chun
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Hyun Joon An
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Ohyun Kwon
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Do Hoon Oh
- Department of Radiation Oncology, Chung-Ang University Hospital, Seoul, Republic of Korea
| | - Jong Min Park
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea; Center for Convergence Research on Robotics, Advanced Institutes of Convergence Technology, Suwon, Republic of Korea
| | - Jung-In Kim
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea; Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.
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Posiewnik M, Piotrowski T. A review of cone-beam CT applications for adaptive radiotherapy of prostate cancer. Phys Med 2019; 59:13-21. [DOI: 10.1016/j.ejmp.2019.02.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/29/2019] [Accepted: 02/15/2019] [Indexed: 11/26/2022] Open
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Najem MA, Tedder M, King D, Bernstein D, Trouncer R, Meehan C, Bidmead AM. In-vivo EPID dosimetry for IMRT and VMAT based on through-air predicted portal dose algorithm. Phys Med 2018; 52:143-153. [PMID: 30139603 DOI: 10.1016/j.ejmp.2018.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 07/02/2018] [Accepted: 07/24/2018] [Indexed: 11/28/2022] Open
Abstract
We have adapted the methodology of Berry et al. (2012) for Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) treatments at a fixed source to imager distance (SID) based on the manufacturer's through-air portal dose image prediction algorithm. In order to fix the SID a correction factor was introduced to account for the change in air gap between patient and imager. Commissioning data, collected with multiple field sizes, solid water thicknesses and air gaps, were acquired at 150 cm SID on the Varian aS1200 EPID. The method was verified using six IMRT and seven VMAT plans on up to three different phantoms. The method's sensitivity and accuracy were investigated by introducing errors. A global 3%/3 mm gamma was used to assess the differences between the predicted and measured portal dose images. The effect of a varying air gap on EPID signal was found to be significant - varying by up to 30% with field size, phantom thickness, and air gap. All IMRT plans passed the 3%/3 mm gamma criteria by more than 95% on the three phantoms. 23 of 24 arcs from the VMAT plans passed the 3%/3 mm gamma criteria by more than 95%. This method was found to be sensitive to a range of potential errors. The presented approach provides fast and accurate in-vivo EPID dosimetry for IMRT and VMAT treatments and can potentially replace many pre-treatment verifications.
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Affiliation(s)
- M A Najem
- Joint Department of Physics, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ, UK.
| | - M Tedder
- Medical Physics Department, Guy's and St Thomas' NHS Foundation Trust, London SE1 7EH, UK
| | - D King
- Joint Department of Physics, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ, UK
| | - D Bernstein
- Joint Department of Physics, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ, UK
| | - R Trouncer
- Joint Department of Physics, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ, UK
| | - C Meehan
- Joint Department of Physics, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ, UK
| | - A M Bidmead
- Joint Department of Physics, The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, Fulham Road, London SW3 6JJ, UK
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Park SY, Park JM, Kim JI, Lee S, Choi CH. Validation of new transmission detector transmission factors for online dosimetry: an experimental study. Radiat Oncol 2018; 13:156. [PMID: 30143012 PMCID: PMC6109263 DOI: 10.1186/s13014-018-1106-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 08/20/2018] [Indexed: 01/14/2023] Open
Abstract
Background The demand for dose verification during treatment has risen with the increasing use of intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) in modern radiation therapy. This study aims to validate the transmission factors of a new transmission detector, the Dolphin online monitoring system (IBA Dosimetry, Schwarzenbruck, Germany), for clinical use. Methods The transmission factors of the Dolphin detector were evaluated using 6 MV, 6 flattening filter free (FFF), 10 MV, and 10 FFF clinical beams from a TrueBeam STx linear accelerator system. Two-dimensional (2D) dose distributions were measured through portal dosimetry with and without Dolphin to derive the transmission factors. The measurements were performed using 10 IMRT and 10 VMAT treatment plans. The transmission factors were calculated using a non-negative least squares problem solver for the 2D dose matrix. Normalized plans were generated using the derived transmission factors. Patient-specific quality assurance with normalized plans was performed using portal dosimetry and an ArcCheck detector to verify the transmission factors. The gamma passing rates were calculated for the 2%/2 mm and 1%/1 mm criteria. Results The transmission factors for the 6 MV, 6 FFF, 10 MV, and 10 FFF beams, were 0.878, 0.824, 0.913, and 0.883, respectively. The average dose difference between the original plan without Dolphin and the normalized plan with Dolphin was less than 1.8% for all measurements. The mean passing rates of the gamma evaluation were 98.1 ± 2.1 and 82.9 ± 12.6 for the 2%/2 mm and 1%/1 mm criteria, respectively, for portal dosimetry of the original plan. In the case of the portal dosimetry of the normalized plan, the mean passing rates of the gamma evaluation were 97.2 ± 2.8 and 79.1 ± 14.8 for the 2%/2 mm and 1%/1 mm criteria, respectively. Conclusions The Dolphin detector can be used for online dosimetry when valid transmission factors are applied to the clinical plan.
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Affiliation(s)
- So-Yeon Park
- Department of Radiation Oncology, Veterans Health Service Medical Center, Seoul, Republic of Korea.,Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Jong Min Park
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jung-In Kim
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea.,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Sungyoung Lee
- Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Chang Heon Choi
- Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea. .,Department of Radiation Oncology, Seoul National University Hospital, Seoul, Republic of Korea. .,Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea.
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Bresciani S, Poli M, Miranti A, Maggio A, Di Dia A, Bracco C, Gabriele P, Stasi M. Comparison of two different EPID-based solutions performing pretreatment quality assurance: 2D portal dosimetry versus 3D forward projection method. Phys Med 2018; 52:65-71. [PMID: 30139611 DOI: 10.1016/j.ejmp.2018.06.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 05/13/2018] [Accepted: 06/05/2018] [Indexed: 01/08/2023] Open
Abstract
PURPOSE The aim of this paper is to characterize two different EPID-based solutions for pre-treatment VMAT quality assurance, the 2D portal dosimetry and the 3D projection technique. Their ability to catch the main critical delivery errors was studied. METHODS Measurements were performed with a linac accelerator equipped with EPID aSi1000, Portal Dose Image Prediction (PDIP), and PerFRACTION softwares. Their performances were studied simulating perturbations of a reference plan through systematic variations in dose values and micromultileaf collimator position. The performance of PDIP, based on 2D forward method, was evaluated calculating gamma passing rate (%GP) between no-error and error-simulated measurements. The impact of errors with PerFRACTION, based on 3D projection technique, was analyzed by calculating the difference between reference and perturbed DVH (%ΔD). Subsequently pre-treatment verification with PerFRACTION was done for 27 patients of different pathologies. RESULTS The sensitivity of PerFRACTION was slightly higher than sensitivity of PDIP, reaching a maximum of 0.9. Specificity was 1 for PerFRACTION and 0.6 for PDIP. The analysis of patients' DVHs indicated that the mean %ΔD was (1.2 ± 1.9)% for D2%, (0.6 ± 1.7)% for D95% and (-0.0 ± 1.2)% for Dmean of PTV. Regarding OARs, we observed important discrepancies on DVH but that the higher dose variations were in low dose area (<10 Gy). CONCLUSIONS This study supports the introduction of the new 3D forward projection method for pretreatment QA raising the claim that the visualization of the delivered dose distribution on patient anatomy has major advantages over traditional portal dosimetry QA systems.
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Affiliation(s)
- Sara Bresciani
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy.
| | - Matteo Poli
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
| | - Anna Miranti
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
| | - Angelo Maggio
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
| | - Amalia Di Dia
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
| | - Christian Bracco
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
| | - Pietro Gabriele
- Radiotherapy Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
| | - Michele Stasi
- Medical Physics Division, Candiolo Cancer Institute - FPO, IRCCS, Strada Provinciale 142 km 3.95, 10060 Candiolo (TO), Italy
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