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Tarutani K. [Basics of IMRT Dose Verification Methodology and Tolerances: Explanation of AAPM TG-218]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2024; 80:226-232. [PMID: 38382982 DOI: 10.6009/jjrt.2024-2316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Affiliation(s)
- Kazuo Tarutani
- Japan Organization of Occupational Health and Safety Kansai Rosai Hospital
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Wesolowska P, Slusarczyk-Kacprzyk W, Fillmann M, Kazantsev P, Bulski W. Results of the IAEA supported national end-to-end audit of the IMRT technique in Poland. Phys Med 2023; 116:103168. [PMID: 37984129 DOI: 10.1016/j.ejmp.2023.103168] [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: 03/16/2023] [Revised: 10/09/2023] [Accepted: 11/05/2023] [Indexed: 11/22/2023] Open
Abstract
The dosimetry audit services were established in Poland in 1991, since then new audits have been introduced. The recently developed IAEA audit methodology for IMRT H&N treatments was tested nationally. Anthropomorphic SHANE phantom (CIRS) was used to perform measurements in 8 hospitals which voluntarily participated in the study. Each participant had to complete successfully pre-visit activities to take part in an onsite visit. During the visit, auditors together with the local staff, did a CT scan using local protocol, recalculated the plan and verified all the relevant parameters and performed measurements with an ionization chamber and films in SHANE. The adoption of IAEA methodology to the national circumstances was done with no major issues. Participants plans were verified and the results of ionization chamber were all within the 5 % tolerance limit for PTV (max 4,5%) and 7 % for OAR (max 5,3%). Film global gamma results (3 %, 3 mm, 90 % acceptance limit) were within 91,5-99,7% range. The IAEA established acceptance criteria which were achievable for most tests except for CTtoRED conversion curve. The locally performed study allowed establishing new limits. The audit gave interesting results and showed that the procedure is very thorough and capable to identify issues related with suboptimal treatment preparation and delivery. The new limits for CTtoRED conversion curve were adopted for national study. Such an audit gives an opportunity to verify the quality of locally implemented procedures and should be available for Polish hospitals on a daily basis.
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Affiliation(s)
- Paulina Wesolowska
- Department of Medical Physics, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland.
| | | | - Marta Fillmann
- Department of Medical Physics, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
| | - Pavel Kazantsev
- Dosimetry Laboratory, Dosimetry and Medical Radiation Physics Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Wojciech Bulski
- Department of Medical Physics, Maria Sklodowska-Curie National Research Institute of Oncology, Warsaw, Poland
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Sheen H, Shin HB, Kim H, Kim C, Kim J, Kim JS, Hong CS. Application of error classification model using indices based on dose distribution for characteristics evaluation of multileaf collimator position errors. Sci Rep 2023; 13:11027. [PMID: 37419940 PMCID: PMC10328946 DOI: 10.1038/s41598-023-35570-1] [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: 09/13/2022] [Accepted: 05/20/2023] [Indexed: 07/09/2023] Open
Abstract
This study aims to evaluate the specific characteristics of various multileaf collimator (MLC) position errors that are correlated with the indices using dose distribution. The dose distribution was investigated using the gamma, structural similarity, and dosiomics indices. Cases from the American Association of Physicists in Medicine Task Group 119 were planned, and systematic and random MLC position errors were simulated. The indices were obtained from distribution maps and statistically significant indices were selected. The final model was determined when all values of the area under the curve, accuracy, precision, sensitivity, and specificity were higher than 0.8 (p < 0.05). The dose-volume histogram (DVH) relative percentage difference between the error-free and error datasets was examined to investigate clinical relations. Seven multivariate predictive models were finalized. The common significant dosiomics indices (GLCM Energy and GLRLM_LRHGE) can characterize the MLC position error. In addition, the finalized logistic regression model for MLC position error prediction showed excellent performance with AUC > 0.9. Furthermore, the results of the DVH were related to dosiomics analysis in that it reflects the characteristics of the MLC position error. It was also shown that dosiomics analysis could provide important information on localized dose-distribution differences in addition to DVH information.
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Affiliation(s)
- Heesoon Sheen
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Han-Back Shin
- Department of Radiation Oncology, Gachon University Gil Medical Center, Incheon, South Korea
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Hojae Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Seoul, South Korea
| | - Changhwan Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Jihun Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Jin Sung Kim
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea
| | - Chae-Seon Hong
- Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, South Korea.
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Alaswad M. Locally advanced non-small cell lung cancer: current issues and recent trends. Rep Pract Oncol Radiother 2023; 28:286-303. [PMID: 37456701 PMCID: PMC10348324 DOI: 10.5603/rpor.a2023.0019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 03/29/2023] [Indexed: 07/18/2023] Open
Abstract
The focus of this paper was to review and summarise the current issues and recent trends within the framework of locally advanced (LA) non-small cell lung cancer (NSCLC). The recently proposed 8th tumour-node-metastases (TNM) staging system exhibited significant amendments in the distribution of the T and M descriptors. Every revision to the TNM classification should contribute to clinical improvement. This is particularly necessary regarding LA NSCLC stratification, therapy and outcomes. While several studies reported the superiority of the 8th TNM edition in comparison to the previous 7th TNM edition, in terms of both the discrimination ability among the various T subgroups and clinical outcomes, others argued against this interpretation. Synergistic cytotoxic chemotherapy with radiotherapy is most prevalent in treating LA NSCLC. Clinical trial experience from multiple references has reported that the risk of locoregional relapse and distant metastasis was less evident for patients treated with concomitant radiochemotherapy than radiotherapy alone. Nevertheless, concern persists as to whether major incidences of toxicity may occur due to the addition of chemotherapy. Cutting-edge technologies such as four-dimensional computed tomography (4D-CT) and volumetric modulated arc therapy (VMAT) should yield therapeutic gains due to their capability to conform radiation doses to tumours. On the basis of the preceding notion, the optimum radiotherapy technique for LA NSCLC has been a controversial and much-disputed subject within the field of radiation oncology. Notably, no single-perspective research has been undertaken to determine the optimum radiotherapy modality for LA NSCLC. The landscape of immunotherapy in lung cancer is rapidly expanding. Currently, the standard of care for patients with inoperable LA NSCLC is concurrent chemoradiotherapy followed by maintenance durvalumab according to clinical outcomes from the PACIFIC trial. An estimated 42.9% of patients randomly assigned to durvalumab remained alive at five years, and free of disease progression, thereby establishing a new benchmark for the standard of care in this setting.
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Affiliation(s)
- Mohammed Alaswad
- Comprehensive Cancer Centre, Radiation Oncology, King Fahad Medical City, Riyadh, Kingdom of Saudi Arabia
- Princess Nourah Bint Abdulrahman University, Riyadh, Kingdom of Saudi Arabia
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Panetta JV, Veltchev I, Price RA, Ma CMC. 2D IMRT QA passing rate dependency on coronal plane. Phys Med 2023; 110:102594. [PMID: 37116388 DOI: 10.1016/j.ejmp.2023.102594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 04/30/2023] Open
Abstract
Intensity modulated radiation therapy (IMRT) delivery involves a complex series of beam angles and multileaf collimator (MLC) arrangements, requiring quality assurance to be performed to validate delivery before treatment. The purpose of this work is to investigate the effect of dose gradient on quality assurance (QA) passing rate. Many (n = 40) IMRT plans were delivered and measured using a 2D planar array of ion chambers; additionally, eleven plans were measured at several coronal planes. For each measurement, dose gradient was assessed using a number of metrics and passing rate assessed at both 3%/3 mm and 3%/2 mm criteria. The passing rates of the various IMRT plans were shown to be generally correlated to gradient, with an average distance correlation of 0.54 ± 0.04 for the lateral dose gradient. The passing rate for an individual plan was shown to vary with coronal slice, though the correlation to dose gradient was not predictable. Even though the passing rate was strongly related to dose gradient for many of the plans, the signs of the correlations were not always negative, as hypothesized. The coronal plane at which QA is performed affects passing rate, though dose gradient may not easily be used to predict slices at which passing rate is higher.
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Affiliation(s)
- Joseph V Panetta
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA.
| | - Iavor Veltchev
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Robert A Price
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - C-M Charlie Ma
- Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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Chan LT, Tan YI, Tan PW, Leong YF, Khor JS, Teh MW, Cruz JFL, Baggarley SP, Ooi KH, Leong YH. Comparing log file to measurement-based patient-specific quality assurance. Phys Eng Sci Med 2023; 46:303-311. [PMID: 36689188 DOI: 10.1007/s13246-023-01219-6] [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: 10/20/2022] [Accepted: 01/09/2023] [Indexed: 01/24/2023]
Abstract
Recent technological advances have allowed the possibility of performing patient-specific quality assurance (QA) without time-intensive measurements. The objectives of this study are to: (1) compare how well the log file-based Mobius QA system agrees with measurement-based QA methods (ArcCHECK and portal dosimetry, PD) in passing and failing plans, and; (2) evaluate their error sensitivities. To these ends, ten phantom plans and 100 patient plans were measured with ArcCHECK and PD on VitalBeam, while log files were sent to Mobius for dose recalculation. Gamma evaluation was performed using criteria 3%/2 mm, per TG218 recommendations, and non-inferiority of the Mobius recalculation was determined with statistical testing. Ten random plans were edited to include systematic errors, then subjected to QA. Receiver operating characteristic curves were constructed to compare error sensitivities across the QA systems, and clinical significance of the errors was determined by recalculating dose to patients. We found no significant difference between Mobius, ArcCHECK, and PD in passing plans at the TG218 action limit. Mobius showed good sensitivity to collimator and gantry errors but not MLC bank shift errors, but could flag discrepancies in treatment delivery. Systematic errors were clinically significant only at large magnitudes; such unacceptable plans did not pass QA checks at the TG218 tolerance limit. Our results show that Mobius is not inferior to existing measurement-based QA systems, and can supplement existing QA practice by detecting real-time delivery discrepancies. However, it is still important to maintain rigorous routine machine QA to ensure reliability of machine log files.
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Affiliation(s)
- Li Ting Chan
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore.
| | - Yun Inn Tan
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Poh Wee Tan
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Yuh Fun Leong
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Jong Shin Khor
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Mun Woan Teh
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Joan Faith Loria Cruz
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Sháun Peter Baggarley
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Kiat Huat Ooi
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
| | - Yiat Horng Leong
- Radiation Therapy Centre, National University Cancer Institute Singapore, Singapore, Singapore
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Prentou G, Pappas EP, Prentou E, Yakoumakis N, Paraskevopoulou C, Koutsouveli E, Pantelis E, Papagiannis P, Karaiskos P. Impact of systematic MLC positional uncertainties on the quality of single-isocenter multi-target VMAT-SRS treatment plans. J Appl Clin Med Phys 2022; 23:e13708. [PMID: 35733367 PMCID: PMC9359048 DOI: 10.1002/acm2.13708] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Accepted: 06/08/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose To study the impact of systematic MLC leaf positional uncertainties (stemming from mechanical inaccuracies or sub‐optimal MLC modeling) on the quality of intracranial single‐isocenter multi‐target VMAT‐SRS treatment plans. An estimation of appropriate tolerance levels is attempted. Methods Five patients, with three to four metastases and at least one target lying in close proximity to organs‐at‐risk (OARs) were included in this study. A single‐isocenter multi‐arc VMAT plan per patient was prepared, which served as the reference for dosimetric impact evaluation. A range of leaf offsets was introduced (±0.03 mm up to ±0.30 mm defined at the MLC plane) to both leaf banks, by varying the leaf offset MLC modeling parameter in Monaco for all the prepared plans, in order to simulate projected leaf offsets of ±0.09 mm up to ±0.94 mm at the isocenter plane, respectively. For all offsets simulated and cases studied, dose distributions were re‐calculated and compared with the corresponding reference ones. An experimental dosimetric procedure using the SRS mapCHECK diode array was also performed to support the simulation study results and investigate its suitability to detect small systematic leaf positional errors. Results Projected leaf offsets of ±0.09 mm were well‐tolerated with respect to both target dosimetry and OAR‐sparing. A linear relationship was found between D95% percentage change and projected leaf offset (slope: 12%/mm). Impact of projected offset on target dosimetry was strongly associated with target volume. In two cases, plans that could be considered potentially clinically unacceptable (i.e., clinical dose constraint violation) were obtained even for projected offsets as small as 0.19 mm. The performed experimental dosimetry check can detect potential small systematic leaf errors. Conclusions Plan quality indices and dose–volume metrics are very sensitive to systematic sub‐millimeter leaf positional inaccuracies, projected at the isocenter plane. Acceptable and tolerance levels in systematic MLC uncertainties need to be tailored to VMAT‐SRS spatial and dosimetric accuracy requirements.
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Affiliation(s)
- Georgia Prentou
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleftherios P Pappas
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleni Prentou
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | | | | | - Evaggelos Pantelis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis Papagiannis
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Pantelis Karaiskos
- Medical Physics Laboratory, Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Barnes M, Pomare D, Doebrich M, Standen TS, Wolf J, Greer P, Simpson J. Insensitivity of machine log files to MLC leaf backlash and effect of MLC backlash on clinical dynamic MLC motion: An experimental investigation. J Appl Clin Med Phys 2022; 23:e13660. [PMID: 35678793 PMCID: PMC9512360 DOI: 10.1002/acm2.13660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/09/2022] [Accepted: 05/11/2022] [Indexed: 12/02/2022] Open
Abstract
Purpose Multi‐leaf‐collimator (MLC) leaf position accuracy is important for accurate dynamic radiotherapy treatment plan delivery. Machine log files have become widely utilized for quality assurance (QA) of such dynamic treatments. The primary aim is to test the sensitivity of machine log files in comparison to electronic portal imaging device (EPID)‐based measurements to MLC position errors caused by leaf backlash. The secondary aim is to investigate the effect of MLC leaf backlash on MLC leaf motion during clinical dynamic plan delivery. Methods The sensitivity of machine log files and two EPID‐based measurements were assessed via a controlled experiment, whereby the length of the “T” section of a series of 12 MLC leaf T‐nuts in a Varian Millennium MLC for a Trilogy C‐series type linac was reduced by sandpapering the top of the “T” to introduce backlash. The built‐in machine MLC leaf backlash test as well as measurements for two EPID‐based dynamic MLC positional tests along with log files were recorded pre‐ and post‐T‐nut modification. All methods were investigated for sensitivity to the T‐nut change by assessing the effect on measured MLC leaf positions. A reduced version of the experiment was repeated on a TrueBeam type linac with Millennium MLC. Results No significant differences before and after T‐nut modification were detected in any of the log file data. Both EPID methods demonstrated sensitivity to the introduced change at approximately the expected magnitude with a strong dependence observed with gantry angle. EPID‐based data showed MLC positional error in agreement with the micrometer measured T‐nut length change to 0.07 ± 0.05 mm (1 SD) using the departmental routine QA test. Backlash results were consistent between linac types. Conclusion Machine log files appear insensitive to MLC position errors caused by MLC leaf backlash introduced via the T‐nut. The effect of backlash on clinical MLC motions is heavily gantry angle dependent.
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Affiliation(s)
- Michael Barnes
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia.,School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales, Australia
| | - Dennis Pomare
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia
| | - Marcus Doebrich
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia
| | - Therese S Standen
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia
| | - Joshua Wolf
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia.,Icon Cancer Centre Maitland, Maitland Private Hospital, Maitland, New South Wales, Australia
| | - Peter Greer
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia.,School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales, Australia
| | - John Simpson
- Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia.,School of Mathematical and Physical Sciences, University of Newcastle, Newcastle, New South Wales, Australia
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Sivabhaskar S, Li R, Roy A, Kirby N, Fakhreddine M, Papanikolaou N. Machine learning models to predict the delivered positions of Elekta multileaf collimator leaves for volumetric modulated arc therapy. J Appl Clin Med Phys 2022; 23:e13667. [PMID: 35670318 PMCID: PMC9359011 DOI: 10.1002/acm2.13667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/12/2022] [Accepted: 05/15/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Accurate positioning of multileaf collimator (MLC) leaves during volumetric modulated arc therapy (VMAT) is essential for accurate treatment delivery. We developed a linear regression, support vector machine, random forest, extreme gradient boosting (XGBoost), and an artificial neural network (ANN) for predicting the delivered leaf positions for VMAT plans. METHODS For this study, 160 MLC log files from 80 VMAT plans were obtained from a single institution treated on 3 Elekta Versa HD linear accelerators. The gravity vector, X1 and X2 jaw positions, leaf gap, leaf position, leaf velocity, and leaf acceleration were extracted and used as model inputs. The models were trained using 70% of the log files and tested on the remaining 30%. Mean absolute error (MAE), root mean square error (RMSE), the coefficient of determination R2 , and fitted line plots showing the relationship between delivered and predicted leaf positions were used to evaluate model performance. RESULTS The models achieved the following errors: linear regression (MAE = 0.158 mm, RMSE = 0.225 mm), support vector machine (MAE = 0.141 mm, RMSE = 0.199 mm), random forest (MAE = 0.161 mm, RMSE = 0.229 mm), XGBoost (MAE = 0.185 mm, RMSE = 0.273 mm), and ANN (MAE = 0.361 mm, RMSE = 0.521 mm). A significant correlation between a plan's gamma passing rate (GPR) and the prediction errors of linear regression, support vector machine, and random forest is seen (p < 0.045). CONCLUSIONS We examined various models to predict the delivered MLC positions for VMAT plans treated with Elekta linacs. Linear regression, support vector machine, random forest, and XGBoost achieved lower errors than ANN. Models that can accurately predict the individual leaf positions during treatment can help identify leaves that are deviating from the planned position, which can improve a plan's GPR.
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Affiliation(s)
- Sruthi Sivabhaskar
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Ruiqi Li
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Arkajyoti Roy
- Department of Management Science and Statistics, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Neil Kirby
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Mohamad Fakhreddine
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Nikos Papanikolaou
- Department of Radiation Oncology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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Zhang H, Lu W, Cui H, Li Y, Yi X. Assessment of Statistical Process Control Based DVH Action Levels for Systematic Multi-Leaf Collimator Errors in Cervical Cancer RapidArc Plans. Front Oncol 2022; 12:862635. [PMID: 35664736 PMCID: PMC9157499 DOI: 10.3389/fonc.2022.862635] [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: 01/26/2022] [Accepted: 04/19/2022] [Indexed: 11/18/2022] Open
Abstract
Background In the patient-specific quality assurance (QA), DVH is a critical clinically relevant parameter that is finally used to determine the safety and effectiveness of radiotherapy. However, a consensus on DVH-based action levels has not been reached yet. The aim of this study is to explore reasonable DVH-based action levels and optimal DVH metrics in detecting systematic MLC errors for cervical cancer RapidArc plans. Methods In this study, a total of 148 cervical cancer RapidArc plans were selected and measured with COMPASS 3D dosimetry system. Firstly, the patient-specific QA results of 110 RapidArc plans were retrospectively reviewed. Then, DVH-based action limits (AL) and tolerance limits (TL) were obtained by statistical process control. Secondly, systematic MLC errors were introduced in 20 RapidArc plans, generating 380 modified plans. Then, the dose difference (%DE) in DVH metrics between modified plans and original plans was extracted from measurement results. After that, the linear regression model was used to investigate the detection limits of DVH-based action levels between %DE and systematic MLC errors. Finally, a total of 180 test plans (including 162 error-introduced plans and 18 original plans) were prepared for validation. The error detection rate of DVH-based action levels was compared in different DVH metrics of 180 test plans. Results A linear correlation was found between systematic MLC errors and %DE in all DVH metrics. Based on linear regression model, the systematic MLC errors between -0.94 mm and 0.88 mm could be caught by the TL of PTV95 ([-1.54%, 1.51%]), and the systematic MLC errors between -1.00 mm and 0.80 mm could also be caught by the TL of PTVmean ([-2.06%, 0.38%]). In the validation, for original plans, PTV95 showed the minimum error detection rate of 5.56%. For error-introduced plans with systematic MLC errors more than 1mm, PTVmean showed the maximum error detection rate of 88.89%, and then was followed by PTV95 (86.67%). All the TL of DVH metrics showed a poor error detection rate in identifying error-induced plans with systematic MLC errors less than 1mm. Conclusion In 3D quality assurance of cervical cancer RapidArc plans, process-based tolerance limits showed greater advantages in distinguishing plans introduced with systematic MLC errors more than 1mm, and reasonable DVH-based action levels can be acquired through statistical process control. During DVH-based verification, main focus should be on the DVH metrics of target volume. OARs in low-dose regions were found to have a relatively higher dose sensitivity to smaller systematic MLC errors, but may be accompanied with higher false error detection rate.
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Affiliation(s)
- Hanyin Zhang
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wenli Lu
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Haixia Cui
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Ying Li
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xin Yi
- Department of Oncology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Boudet J, Aubignac L, Beneux A, Mazoyer F, Bessieres I. Evaluation of QA software system analysis for the static picket fence test. J Appl Clin Med Phys 2022; 23:e13618. [PMID: 35570379 PMCID: PMC9278673 DOI: 10.1002/acm2.13618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 02/01/2022] [Accepted: 04/01/2022] [Indexed: 11/16/2022] Open
Abstract
Intensity modulation treatments are widely used in radiotherapy because of many known advantages. In this context, the picket fence test (PF) is a relevant test to check the Multileaf Collimator (MLC) performances. So this work compares and evaluates three analysis platforms for the PF used routinely by three different institutions. This study covers two linear accelerators (Linac) with two MLC types, a Millenium 120 MLC and Millenium 120 High Definition MLC respectively on a Varian Truebeam and Truebeam STx. Both linacs include an As 1200 portal imager (EPID). From a reference PF plan, MLC errors have been introduced to modify the slits in position or width (shifts from 0.1 to 0.5 mm on one or both banks). Then errors have been defined on the EPID to investigate detection system deviations (signal sensitivity and position variations). Finally, 110 DICOM‐RT images have been generated and analyzed by each software system. All software systems have shown good performances to quantify the position errors, even though the leaf pair identifications can be wrong in some cases regarding the analysis method considered. The slit width measurement (not calculated by all software systems) has shown good sensitivity, but some quantification difficulties have been highlighted regardless of the analysis method used. Linked to the expected accuracy of the PF test, the imager variations have demonstrated considerable influence in the results. Differences in the results and the analysis methods have been pointed out for each software system. The results can be helpful to optimize the settings of each analysis software system depending on expectations and treatment modalities of each institution.
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Affiliation(s)
- Julien Boudet
- Department of Physics Centre Georges François Leclerc Dijon France
| | - Léone Aubignac
- Department of Physics Centre Georges François Leclerc Dijon France
| | - Amandine Beneux
- Department of Physics Hospices Civils de Lyon Pierre Bénite France
| | - Frédéric Mazoyer
- Department of Radiotherapy Centre Hospitalier Annecy Genevois Epagny Metz‐Tessy France
| | - Igor Bessieres
- Department of Physics Centre Georges François Leclerc Dijon France
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12
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Tatsumi D. [2. Considerations for Radiation Treatment Planning from Medical Accelerators]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2022; 78:526-530. [PMID: 35598962 DOI: 10.6009/jjrt.2022-2018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
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13
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Gray A, Bawazeer O, Arumugam S, Vial P, Descallar J, Thwaites D, Holloway L. Evaluation of the ability of three commercially available dosimeters to detect systematic delivery errors in step-and-shoot IMRT plans. Rep Pract Oncol Radiother 2021; 26:793-803. [PMID: 34760314 DOI: 10.5603/rpor.a2021.0093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 07/03/2021] [Indexed: 11/25/2022] Open
Abstract
Background There is limited data on error detectability for step-and-shoot intensity modulated radiotherapy (sIMRT) plans, despite significant work on dynamic methods. However, sIMRT treatments have an ongoing role in clinical practice. This study aimed to evaluate variations in the sensitivity of three patient-specific quality assurance (QA) devices to systematic delivery errors in sIMRT plans. Materials and methods Four clinical sIMRT plans (prostate and head and neck) were edited to introduce errors in: Multi-Leaf Collimator (MLC) position (increasing field size, leaf pairs offset (1-3 mm) in opposite directions; and field shift, all leaves offset (1-3 mm) in one direction); collimator rotation (1-3 degrees) and gantry rotation (0.5-2 degrees). The total dose for each plan was measured using an ArcCHECK diode array. Each field, excluding those with gantry offsets, was also measured using an Electronic Portal Imager and a MatriXX Evolution 2D ionisation chamber array. 132 plans (858 fields) were delivered, producing 572 measured dose distributions. Measured doses were compared to calculated doses for the no-error plan using Gamma analysis with 3%/3 mm, 3%/2 mm, and 2%/2 mm criteria (1716 analyses). Results Generally, pass rates decreased with increasing errors and/or stricter gamma criteria. Pass rate variations with detector and plan type were also observed. For a 3%/3 mm gamma criteria, none of the devices could reliably detect 1 mm MLC position errors or 1 degree collimator rotation errors. Conclusions This work has highlighted the need to adapt QA based on treatment plan type and the need for detector specific assessment criteria to detect clinically significant errors.
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Affiliation(s)
- Alison Gray
- Liverpool and Macarthur Cancer Therapy Centres, South Western Sydney Local Health District, Sydney, NSW, Australia.,Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,South Western Sydney Clinical School, School of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Omemh Bawazeer
- Physics Department, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Sankar Arumugam
- Liverpool and Macarthur Cancer Therapy Centres, South Western Sydney Local Health District, Sydney, NSW, Australia.,Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,South Western Sydney Clinical School, School of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Philip Vial
- Liverpool and Macarthur Cancer Therapy Centres, South Western Sydney Local Health District, Sydney, NSW, Australia.,Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,South Western Sydney Clinical School, School of Medicine, University of New South Wales, Sydney, NSW, Australia.,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
| | - Joseph Descallar
- Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,South Western Sydney Clinical School, School of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - David Thwaites
- Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia
| | - Lois Holloway
- Liverpool and Macarthur Cancer Therapy Centres, South Western Sydney Local Health District, Sydney, NSW, Australia.,Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.,South Western Sydney Clinical School, School of Medicine, University of New South Wales, Sydney, NSW, Australia.,Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia.,Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia
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14
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Zhu TC, Stathakis S, Clark JR, Feng W, Georg D, Holmes SM, Kry SF, Ma CMC, Miften M, Mihailidis D, Moran JM, Papanikolaou N, Poppe B, Xiao Y. Report of AAPM Task Group 219 on independent calculation-based dose/MU verification for IMRT. Med Phys 2021; 48:e808-e829. [PMID: 34213772 DOI: 10.1002/mp.15069] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/25/2021] [Accepted: 06/21/2021] [Indexed: 11/06/2022] Open
Abstract
Independent verification of the dose per monitor unit (MU) to deliver the prescribed dose to a patient has been a mainstay of radiation oncology quality assurance (QA). We discuss the role of secondary dose/MU calculation programs as part of a comprehensive QA program. This report provides guidelines on calculation-based dose/MU verification for intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) provided by various modalities. We provide a review of various algorithms for "independent/second check" of monitor unit calculations for IMRT/VMAT. The report makes recommendations on the clinical implementation of secondary dose/MU calculation programs; on commissioning and acceptance of various commercially available secondary dose/MU calculation programs; on benchmark QA and periodic QA; and on clinically reasonable action levels for agreement of secondary dose/MU calculation programs.
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Affiliation(s)
- Timothy C Zhu
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Wenzheng Feng
- Department of Radiation Oncology, Columbia University, New York, NY, USA
| | - Dietmar Georg
- Department of Radiation Oncology, Medical University Vienna, Vienna, Austria
| | | | - Stephen F Kry
- IROC, UT MD Anderson Cancer Center, Houston, TX, USA
| | | | - Moyed Miften
- Department of Radiation Oncology, University of Colorado Denver, Aurora, CO, USA
| | - Dimitris Mihailidis
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
| | - Jean M Moran
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | | | - Bjorn Poppe
- Pius Hospital & Carl von Ossietzky University, Oldenburg, Germany
| | - Ying Xiao
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA, USA
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15
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Rohani SA, Mahdavi SR, Mostaar A, Rahimi S, Mohammadi R, Geraily G. Commissioning and quality assurance of Euromechanics add-on multileaf collimator. Biomed Phys Eng Express 2020; 7. [PMID: 34037543 DOI: 10.1088/2057-1976/abbd23] [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: 06/04/2020] [Accepted: 09/30/2020] [Indexed: 11/11/2022]
Abstract
In this study, the beam characteristics of a Euromechanics add-on MLC that has been installed on a Varian CLINAC 2100 C/D linear accelerator are presented. This was the first installation of 60-leaf PMLC from Euromechanics Company worldwide and all mechanical and dosimetric parameters were measured before clinical use of this kind of MLC. Mechanical tests were executed for different gantry and collimator angles. Leaf position accuracy and leaf gap reproducibility were checked with four different tests. The leaf transmissions, collimator (Sc), phantom (Sp), total (Sc,p) scatter factors, output of the machine, beam profiles for off-axis ratios, central axis depth dose, flatness, symmetry and penumbra have been measured for different field sizes pre and post MLC installation in 6 and 18 MV-mode. To evaluate the effect of new data on clinical plans, different beam setup configurations conformed with MLC and custom blocks were planned on CT images of thorax a CIRS phantom model 002LFC in the same treatment planning system. Leaf position in picket fence test found to be in range between 4.89-5.02 cm instead of nominal 5 cm, however the results of this test with EPIDs image and PIPSpro software showed the higher deviation rather than the results reported from the tests with EBT3 films. The measured data showed that on average Sc,p and Sc were increased 0.22% (P = 0.86) and 0.34% (P = 0.86) for 6 MV and 0.37% (P = 0.84) and 0.42% (P = 0.88) for 18 MV beams for different field sizes, respectively. Good agreement was observed between the PDD and profile curves pre and post MLC installation that was expected based on no changes in beam energy and geometry of the collimators. Based on the mechanical and dosimetry results which have been achieved from our different standard tests, it was found no significant differences between pre and post MLC installation values. This indicates, installation and using this system is clinically acceptable.
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Affiliation(s)
| | - Seied Rabi Mahdavi
- Medical Physics Department, Faculty of Medicine, Iran University of Medical Science, Tehran, Iran.,Radiation Biology Research Center, Iran Department of Medical Physics, School of Medicine, Tehran, Iran
| | - Ahmad Mostaar
- Radiation Biology Research Center, Iran Department of Medical Physics, School of Medicine, Tehran, Iran.,Department of Medical Physics, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Reza Mohammadi
- Medical Physics Department, Faculty of Medicine, Iran University of Medical Science, Tehran, Iran
| | - Ghazale Geraily
- Department of Medical Physics, Tehran University of Medical Science, Tehran, Iran
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16
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Retrospective analysis of portal dosimetry pre-treatment quality assurance of hybrid IMRT breast treatment plans. JOURNAL OF RADIOTHERAPY IN PRACTICE 2020. [DOI: 10.1017/s1460396920000072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
AbstractBackground:The purpose of this study is to evaluate the effectiveness and sensitivity of the Varian portal dosimetry (PD) system as a quality assurance (QA) tool for breast intensity-modulated radiation therapy (IMRT) treatment plans.Materials and methods:Four hundred portal dose images from 200 breast cancer patient IMRT treatment plans were analysed. The images were obtained using Varian PortalVision electronic portal imaging devices (EPIDs) on Varian TrueBeam Linacs. Three patient plans were selected, and the multi-leaf collimator (MLC) positions were randomly altered by a mean of 0·5, 1, 1·5 and 2 mm with a standard deviation of 0·1 mm on 50, 75 and 100% of control points. Using the improved/global gamma calculation algorithm with a low-dose threshold of 10% in the EPID, the change in gamma passing rates for 3%/3 mm, 2%/2 mm and 1%/1 mm criterion was analysed as a function of the introduced error. The changes in the dose distributions of clinical target volume and organ at risk due to MLC positioning errors were also analysed.Results:Symmetric and asymmetric breast or chest wall plan fields are different in delivery as well as in the QA. An average gamma passing rate of 99·8 ± 0·5 is presented for 3%/3 mm symmetric plans and 96·9 ± 4·5 is presented for 3%/3 mm asymmetric plans. An average gamma passing rate of 98·4 ± 4·3 is presented for 2%/2 mm symmetric plans and 89·7 ± 9·5 is presented for 2%/2 mm asymmetric plans. A large-induced error in MLC positioning (2·0 mm, 100% of control points) results in an insignificant change in dose that would be delivered to the patient. However, EPID portal dosimetry is sensitive enough to detect even the slightest change in MLC positioning error (0·5 mm, 50% of control points).Conclusions:Stricter pre-treatment QA action levels can be established for breast IMRT plans utilising EPID. For improved sensitivity, a multigamma criteria approach is recommended. The PD tool is sensitive enough to detect MLC positioning errors that contribute to even insignificant dose changes.
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17
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Mittauer KE, Yadav P, Paliwal B, Bayouth JE. Characterization of positional accuracy of a double‐focused and double‐stack multileaf collimator on an MR‐guided radiotherapy (MRgRT) Linac using an IC‐profiler array. Med Phys 2019; 47:317-330. [DOI: 10.1002/mp.13902] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 11/07/2022] Open
Affiliation(s)
- Kathryn E. Mittauer
- Department of Radiation Oncology Miami Cancer Institute Baptist Health South Florida Miami FL USA
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
| | - Poonam Yadav
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
| | - Bhudatt Paliwal
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
| | - John E. Bayouth
- Department of Human Oncology School of Medicine and Public Health University of Wisconsin‐Madison Madison WI USA
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18
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Abstract
PURPOSE The IAEA newly developed "end-to-end" audit methodology for on-site verification of IMRT dose delivery has been carried out in Portugal in 2018. The main goal was to evaluate the physical aspects of the head and neck (H&N) cancer IMRT treatments. This paper presents the national results. METHODS All institutions performing IMRT treatments in Portugal, 20 out of 24, have voluntarily participated in this audit. Following the adopted methodology, a Shoulder, Head and Neck End-to-End phantom (SHANE) - that mimics an H&N region, underwent all steps of an IMRT treatment, according to the local practices. The measurements using an ionization chamber placed inside the SHANE phantom at four reference locations (three in PTVs and one in the spinal cord) and an EBT3 film positioned in a coronal plane were compared with calculated doses. FilmQA Pro software was used for film analysis. RESULTS For ionization chamber measurements, the percent difference was within the specified tolerances of ±5% for PTVs and ±7% for the spinal cord in all participating institutions. Considering film analysis, gamma passing rates were on average 96.9%±2.9% for a criterion of 3%/3 mm, 20% threshold, all above the acceptance limit of 90%. CONCLUSIONS The national results of the H&N IMRT audit showed a compliance between the planned and the delivered doses within the specified tolerances, confirming no major reasons for concern. At the same time the audit identified factors that contributed to increased uncertainties in the IMRT dose delivery in some institutions resulting in recommendations for quality improvement.
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19
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Gay SS, Netherton TJ, Cardenas CE, Ger RB, Balter PA, Dong L, Mihailidis D, Court LE. Dosimetric impact and detectability of multi-leaf collimator positioning errors on Varian Halcyon. J Appl Clin Med Phys 2019; 20:47-55. [PMID: 31294923 PMCID: PMC6698762 DOI: 10.1002/acm2.12677] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/06/2019] [Accepted: 06/21/2019] [Indexed: 11/11/2022] Open
Abstract
The purpose of this study is to investigate the dosimetric impact of multi‐leaf collimator (MLC) positioning errors on a Varian Halcyon for both random and systematic errors, and to evaluate the effectiveness of portal dosimetry quality assurance in catching clinically significant changes caused by these errors. Both random and systematic errors were purposely added to 11 physician‐approved head and neck volumetric modulated arc therapy (VMAT) treatment plans, yielding a total of 99 unique plans. Plans were then delivered on a preclinical Varian Halcyon linear accelerator and the fluence was captured by an opposed portal dosimeter. When comparing dose–volume histogram (DVH) values of plans with introduced MLC errors to known good plans, clinically significant changes to target structures quickly emerged for plans with systematic errors, while random errors caused less change. For both error types, the magnitude of clinically significant changes increased as error size increased. Portal dosimetry was able to detect all systematic errors, while random errors of ±5 mm or less were unlikely to be detected. Best detection of clinically significant errors, while minimizing false positives, was achieved by following the recommendations of AAPM TG‐218. Furthermore, high‐ to moderate correlation was found between dose DVH metrics for normal tissues surrounding the target and portal dosimetry pass rates. Therefore, it may be concluded that portal dosimetry on the Halcyon is robust enough to detect errors in MLC positioning before they introduce clinically significant changes to VMAT treatment plans.
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Affiliation(s)
- Skylar S Gay
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Tucker J Netherton
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Carlos E Cardenas
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Rachel B Ger
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Peter A Balter
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Lei Dong
- Radiation Oncology, Hospital, University of Pennsylvania, Philadelphia, PA, USA
| | - Dimitris Mihailidis
- Radiation Oncology, Hospital, University of Pennsylvania, Philadelphia, PA, USA
| | - Laurence E Court
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA.,Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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20
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Bonfantini F, Giandini T, Meroni S, Cavallo A, Stucchi C, Carrara M, Mongioj V, Veronese I, Pignoli E. Application of failure mode and effects analysis to optimization of linac quality controls protocol. Med Phys 2019; 46:2541-2555. [DOI: 10.1002/mp.13538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 01/31/2019] [Accepted: 03/27/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Francesca Bonfantini
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Tommaso Giandini
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Silvia Meroni
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Anna Cavallo
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Claudio Stucchi
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Mauro Carrara
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Valeria Mongioj
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Ivan Veronese
- Physics Department Università degli Studi di Milano and Istituto Nazionale di Fisica Nucleare Sezione di Milano Via Giovanni Celoria 16 20133 Milan Italy
| | - Emanuele Pignoli
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
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21
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Pan Y, Yang R, Zhang S, Li J, Dai J, Wang J, Cai J. National survey of patient specific IMRT quality assurance in China. Radiat Oncol 2019; 14:69. [PMID: 31023348 PMCID: PMC6482589 DOI: 10.1186/s13014-019-1273-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 04/08/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To analyze and present the China's national survey on patient-specific IMRT quality assurance (QA). METHODS A national survey was conducted in all radiotherapy centers in China to collect comprehensive information on status of IMRT QA practice, including machine, technique, equipment, issues and suggestions. RESULTS Four hundred and three centers responded to this survey, accounting for 56.92% of all the centers implementing IMRT in China. The total number of medical physicists and the total number of patients treated with IMRT annually in these centers was 1599 and 305,000 respectively. All centers implemented measurement-based verification. Point dose verification and 2D dose verification was implemented in 331 and 399 centers, respectively. Three hundred forty-eight centers had 2D arrays, and 52 centers had detector devices designed to measure VMAT beams. EPID and film were used in 78 and 70 centers, respectively. Seventeen and 20 centers used log file and 3D DVH analysis, respectively. One hundred sixty-eight centers performed measurement-based verification not for each patient based on different selection criteria. The techniques and methods varied significantly in both point dose and dose distribution verification, from evaluation metrics, criteria, tolerance limit, and steps to check failed IMRT QA plans. Major issues identified in this survey were the limited resources of physicists, QA devices, and linacs. CONCLUSIONS IMRT QA was implemented in all the surveyed centers. The practice of IMRT QA varied significantly between centers. An increase in personnel, QA devices and linacs is highly desired. National standard, guideline, regulation and training programs are urgently needed in China for consistent and effective implementation of IMRT QA.
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Affiliation(s)
- Yuxi Pan
- Department of Radiation Oncology, Peking University Third Hospital, 49th North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - Ruijie Yang
- Department of Radiation Oncology, Peking University Third Hospital, 49th North Garden Road, Haidian District, Beijing, 100191, People's Republic of China.
| | - Shuming Zhang
- Department of Radiation Oncology, Peking University Third Hospital, 49th North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - Jiaqi Li
- Department of Radiation Oncology, Peking University Third Hospital, 49th North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - Jianrong Dai
- Department of Radiation Oncology, Chinese Academy of Medical Science Cancer Institute, 17 Panjiayuan Nanli, Beijing, People's Republic of China
| | - Junjie Wang
- Department of Radiation Oncology, Peking University Third Hospital, 49th North Garden Road, Haidian District, Beijing, 100191, People's Republic of China
| | - Jing Cai
- Department of Health Technology and Informatics, The Hongkong Polytechnic University, Hongkong, People's Republic of China
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22
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Evaluating the dosimetric consequences of MLC leaf positioning errors in dynamic IMRT treatments. JOURNAL OF RADIOTHERAPY IN PRACTICE 2019. [DOI: 10.1017/s1460396918000705] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractPurposeThe purpose of this study was to evaluate the dosimetric impact of multileaf collimator (MLC) positional errors on dynamic intensity-modulated radiotherapy (IMRT) treatments through planning simulation. Secondly the sensitivity of IMRT MatriXX device for detecting the MLC leaf positional errors was also evaluated.Materials and methodsIn this study five dynamic IMRT plans, each for brain and head–neck (HN), were retrospectively included. An in-house software was used to introduce random errors (uniform distribution between −2·0 and +2·0 mm) and systematic errors [±0·5, ±0·75, ±1·0 and ±2·0 mm (+: open MLC error and −: close MLC error)]. The error-introduced MLC files were imported into the treatment planning system and new dose distributions were calculated. Furthermore, the dose–volume histogram files of all plans were exported to in-house software for equivalent uniform dose (EUD), tumour control probability and normal tissue complication probability calculations. The error-introduced plans were also delivered on LINAC, and the planar fluences were measured by IMRT MatriXX. Further, 3%/3 mm and 2%/2 mm γ-criteria were used for analysis.ResultsIn planning simulation study, the impact of random errors was negligible and ΔEUD was <0·5±0·7%, for both brain and HN. The impact of systematic errors was substantial, and on average, the maximum change in EUD for systematic errors (close 2 mm) was −10·7±3·1% for brain and −15·5±2·6% for HN.ConclusionsIt can be concluded that the acceptable systematic error was 0·4 mm for brain and 0·3 mm for HN. Furthermore, IMRT MatriXX device was able to detect the MLC errors ≥2 mm in HN and >3 mm errors in brain with 2%/2 mm γ-criteria.
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23
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Cui T, Ward MC, Joshi NP, Woody NM, Murray EJ, Potter J, Dorfmeyer AA, Greskovich JF, Koyfman SA, Xia P. Correlation between plan quality improvements and reduced acute dysphagia and xerostomia in the definitive treatment of oropharyngeal squamous cell carcinoma. Head Neck 2019; 41:1096-1103. [PMID: 30702180 DOI: 10.1002/hed.25594] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Revised: 10/01/2018] [Accepted: 12/05/2018] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND To evaluate plan quality using volumetric-modulated arc therapy (VMAT) and step-and-shoot intensity-modulated radiation therapy (SS-IMRT) techniques and for patients treated for oropharyngeal squamous cell carcinoma (OPSCC). METHODS Treatment plans for patients treated definitively for stages I-IVb, OPSCC between December 2009 and August 2015 were retrospectively reviewed. Dosimetric endpoints of involved organs-at-risk (OARs) were retrieved from clinical plans. Common Terminology Criteria for Adverse Events scores of acute toxicities were compared. RESULTS Two-hundred twenty-two patients were identified with 134 and 88 receiving SS-IMRT and VMAT with median follow-up time of 23.0 and 7.9 months, respectively. The dosimetric endpoints of the OARs were significantly improved in VMAT cohort, which translated into significantly lower rates of grade 2 or higher acute dysphagia and xerostomia. CONCLUSION Improvements in stages I-IVb, oropharyngeal cancer plan quality are associated with reduced grade ≥ 2 acute dysphagia and xerostomia.
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Affiliation(s)
- Taoran Cui
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio.,Department of Radiation Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, NJ
| | - Matthew C Ward
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio.,Southeast Radiation Oncology, Charlotte, NC
| | - Nikhil P Joshi
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Neil M Woody
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Eric J Murray
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | - John Potter
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Andrew A Dorfmeyer
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | - John F Greskovich
- Department of Radiation Oncology, Cleveland Clinic Florida, Weston, Florida
| | - Shlomo A Koyfman
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
| | - Ping Xia
- Department of Radiation Oncology, Taussig Cancer Center, Cleveland Clinic Foundation, Cleveland, Ohio
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24
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Tamborra P, Martinucci E, Massafra R, Bettiol M, Capomolla C, Zagari A, Didonna V. The 3D isodose structure-based method for clinical dose distributions comparison in pretreatment patient-QA. Med Phys 2018; 46:426-436. [PMID: 30450559 DOI: 10.1002/mp.13297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION Before the approval of any Intensity Modulated Radiation Therapy or Volumetric Modulated Arc Therapy treatment plan, quality assurance (QA) tests are needed to reveal potential errors such as an inaccurate calculation of the dose distribution, the failure of the record-and-verify system, or the delivery system of the linear accelerator. Currently, the method adopted to compare the measured dose distribution with the treatment planning system TPS calculated dose distribution is gamma analysis. However, gamma analysis has been shown to be ineffective for the clinical evaluation of treatment plans. We proposed and tested a new method (the isodose structures method) alternative to gamma analysis. METHOD Different errors were introduced in 33 error-free Head and Neck plans. The modified plans were recalculated using TPS software and the dose distributions obtained were compared to those of the original (error-free) plans. The comparison was performed using gamma analysis and the new method. The target was to calculate overall and organ-specific gamma passing rates as well as the overlapping ratio (OR) and volume ratio (VR) factors of the isodose structures method for each error-included plan. RESULTS Eight of the 33 plans passed both the gamma analysis and the isodose structures (IS) analysis, ten plans did not pass either of them, while 13 plans which did not pass the IS analysis, passed the gamma analysis. Two plans which did not pass gamma, passed IS analysis. Furthermore, Dose Volume Histogram (DVH) metrics could not detect the low agreement between the dose distributions of two error-free plans and the respective modified plans. In this case, the IS analysis also allowed us to detect clinically meaningful differences between measured and TPS dose distributions. CONCLUSIONS The IS method analysis clearly showed a high efficiency in detecting clinically relevant differences between TPS and measured dose distributions not seen in gamma analysis and in DVH-based metrics. Therefore, IS analysis proved to be a valid tool, alternative to gamma analysis for dose comparison in patient-specific QA test.
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Affiliation(s)
- Pasquale Tamborra
- Department of Medical Physics, IRCCS Istituto Tumori "Giovanni Paolo II", Bari, 70124, Italy
| | - Erica Martinucci
- Department of Medical Physics, Hospital "Vito Fazzi" - Cancer Centre "Giovanni Paolo II", Lecce, 70130, Italy
| | - Raffaella Massafra
- Department of Medical Physics, IRCCS Istituto Tumori "Giovanni Paolo II", Bari, 70124, Italy
| | - Marco Bettiol
- Department of Medical Physics, IRCCS Istituto Tumori "Giovanni Paolo II", Bari, 70124, Italy
| | - Caterina Capomolla
- Department of Medical Physics, Hospital "Vito Fazzi" - Cancer Centre "Giovanni Paolo II", Lecce, 70130, Italy
| | - Annarita Zagari
- Department of Medical Physics, Hospital "Vito Fazzi" - Cancer Centre "Giovanni Paolo II", Lecce, 70130, Italy
| | - Vittorio Didonna
- Department of Medical Physics, IRCCS Istituto Tumori "Giovanni Paolo II", Bari, 70124, Italy
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Pogson E, Arumugam S, Hansen C, Currie M, Blake S, Roberts N, Carolan M, Vial P, Alharthi T, Holloway L, Thwaites D. Comparison of multi-institutional pre-treatment verification for VMAT of nasopharynx with delivery errors. Phys Med 2018; 53:25-31. [DOI: 10.1016/j.ejmp.2018.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/19/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022] Open
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Miften M, Olch A, Mihailidis D, Moran J, Pawlicki T, Molineu A, Li H, Wijesooriya K, Shi J, Xia P, Papanikolaou N, Low DA. Tolerance limits and methodologies for IMRT measurement-based verification QA: Recommendations of AAPM Task Group No. 218. Med Phys 2018; 45:e53-e83. [DOI: 10.1002/mp.12810] [Citation(s) in RCA: 373] [Impact Index Per Article: 62.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 12/10/2017] [Accepted: 01/11/2018] [Indexed: 11/07/2022] Open
Affiliation(s)
- Moyed Miften
- Department of Radiation Oncology; University of Colorado School of Medicine; Aurora CO USA
| | - Arthur Olch
- Department of Radiation Oncology; University of Southern California and Radiation Oncology Program; Childrens Hospital of Los Angeles; Los Angeles CA USA
| | - Dimitris Mihailidis
- Department of Radiation Oncology; University of Pennsylvania; Perelman Center for Advanced Medicine; Philadelphia PA USA
| | - Jean Moran
- Department of Radiation Oncology; University of Michigan; Ann Arbor MI USA
| | - Todd Pawlicki
- Department of Radiation Oncology; University of California San Diego; La Jolla CA USA
| | - Andrea Molineu
- Radiological Physics Center; UT MD Anderson Cancer Center; Houston TX USA
| | - Harold Li
- Department of Radiation Oncology; Washington University; St. Louis MO USA
| | - Krishni Wijesooriya
- Department of Radiation Oncology; University of Virginia; Charlottesville VA USA
| | - Jie Shi
- Sun Nuclear Corporation; Melbourne FL USA
| | - Ping Xia
- Department of Radiation Oncology; The Cleveland Clinic; Cleveland OH USA
| | - Nikos Papanikolaou
- Department of Medical Physics; University of Texas Health Sciences Center; San Antonio TX USA
| | - Daniel A. Low
- Department of Radiation Oncology; University of California Los Angeles; Los Angeles CA USA
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Wang Y, Pang X, Feng L, Wang H, Bai Y. Correlation between gamma passing rate and complexity of IMRT plan due to MLC position errors. Phys Med 2018; 47:112-120. [PMID: 29609812 DOI: 10.1016/j.ejmp.2018.03.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 02/13/2018] [Accepted: 03/04/2018] [Indexed: 10/17/2022] Open
Abstract
PURPOSE This study evaluates the correlation between the susceptibility of the γ passing rate of IMRT plans to the multi-leaf collimator (MLC) position errors and a quantitative plan complexity metric. METHODS Twenty patients were selected for this study. For each patient, two IMRT plans were generated using sliding window and step-&-shoot techniques, respectively. Modulation complexity score (MCS) was calculated for all IMRT plans, and symmetric MLC leaf bank errors, ranging from 0.3 mm to 1 mm, were introduced. Original and modified plans were delivered using Varian's Clinac iX. The obtained dose distribution using ArcCHECK was then compared with the TPS calculated dose distribution of the original plans. 3D gamma analysis was performed for each verification with passing criteria of 2%/2 mm. The γ passing rate decreasing gradient were calculated to evaluate relationship between variation of γ passing rate due to MLC errors and complexity. RESULTS A linear regression analysis was applied between γ gradient and complexity, and the results showed a linear correlation (R2 = 0.81 and 0.82 for open and closed MLC error types, respectively) indicating the more complex plans are more susceptible to MLC leaf bank errors. Meanwhile, correlation of re-normalized γ passing rate and complexity for all errors scenarios also presented a strong correlation (r > 0.75). CONCLUSION The statistics results revealed variation relationship of dosimetry robust of plans with various complexities to MLC errors. Our results also suggested that the observed susceptibility is independent of the delivery techniques.
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Affiliation(s)
- Yewei Wang
- Department of Radiation Physics, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, China
| | - Xueying Pang
- Department of Oncology, First Affiliated Hospital, Heilongjiang University of Chinese Medicine, Harbin, China
| | - Lina Feng
- Department of Radiation Physics, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, China
| | - Helong Wang
- Department of Radiation Physics, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, China
| | - Yanling Bai
- Department of Radiation Physics, The Affiliated Tumor Hospital of Harbin Medical University, Harbin, China.
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Ritter TA, Schultz B, Barnes M, Popple R, Perez M, Farrey K, Kim G, Moran JM. Automated EPID-based measurement of MLC leaf offset as a quality control tool. Biomed Phys Eng Express 2018. [DOI: 10.1088/2057-1976/aa9f76] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Blake SJ, Arumugam S, Holloway L, Vinod S, Ochoa C, Phan P, Hansen CR, Thwaites DI. Investigating the impact of treatment delivery uncertainties on treatment effectiveness for lung SABR. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2017; 40:823-829. [DOI: 10.1007/s13246-017-0591-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 10/03/2017] [Indexed: 12/25/2022]
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30
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Pogson EM, Aruguman S, Hansen CR, Currie M, Oborn BM, Blake SJ, Juresic J, Ochoa C, Yakobi J, Haman A, Trtovac A, Carolan M, Holloway L, Thwaites DI. Multi-institutional comparison of simulated treatment delivery errors in ssIMRT, manually planned VMAT and autoplan-VMAT plans for nasopharyngeal radiotherapy. Phys Med 2017; 42:55-66. [DOI: 10.1016/j.ejmp.2017.08.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/03/2017] [Accepted: 08/20/2017] [Indexed: 11/25/2022] Open
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Analysis of Influence of Errors in Angular Settings of Couch and Collimator on the Dosimetric and Radiobiological Parameters in VMAT Plans. J Med Imaging Radiat Sci 2017; 48:166-177. [DOI: 10.1016/j.jmir.2016.10.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/12/2016] [Accepted: 10/25/2016] [Indexed: 12/25/2022]
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Liu S, Mazur TR, Fu Y, Li HH, Mutic S, Yang D. Technical Note: A method to evaluate dosimetric effects on organs-at-risk for treatment delivery systematic uncertainties. Med Phys 2017; 44:1552-1557. [DOI: 10.1002/mp.12135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/23/2017] [Accepted: 01/23/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Shi Liu
- Department of Radiation Oncology; Washington University School of Medicine; St. Louis MO 63110 USA
| | - Thomas R. Mazur
- Department of Radiation Oncology; Washington University School of Medicine; St. Louis MO 63110 USA
| | - Yabo Fu
- Department of Radiation Oncology; Washington University School of Medicine; St. Louis MO 63110 USA
| | - H. Harold Li
- Department of Radiation Oncology; Washington University School of Medicine; St. Louis MO 63110 USA
| | - Sasa Mutic
- Department of Radiation Oncology; Washington University School of Medicine; St. Louis MO 63110 USA
| | - Deshan Yang
- Department of Radiation Oncology; Washington University School of Medicine; St. Louis MO 63110 USA
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Deshpande S, Geurts M, Vial P, Metcalfe P, Lee M, Holloway L. Clinical significance of treatment delivery errors for helical TomoTherapy nasopharyngeal plans – A dosimetric simulation study. Phys Med 2017; 33:159-169. [PMID: 28110824 DOI: 10.1016/j.ejmp.2017.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 12/06/2016] [Accepted: 01/07/2017] [Indexed: 11/17/2022] Open
Affiliation(s)
- Shrikant Deshpande
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.
| | - Mark Geurts
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, USA.
| | - Philip Vial
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW, Australia; Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia.
| | - Peter Metcalfe
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia.
| | - Mark Lee
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW, Australia.
| | - Lois Holloway
- Liverpool and Macarthur Cancer Therapy Centres and Ingham Institute, Sydney, NSW, Australia; Centre for Medical Radiation Physics, University of Wollongong, Wollongong, NSW, Australia; Institute of Medical Physics, School of Physics, University of Sydney, Sydney, NSW, Australia; South West Clinical School, University of New South Wales, Sydney, NSW, Australia.
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Christophides D, Davies A, Fleckney M. Automatic detection of MLC relative position errors for VMAT using the EPID-based picket fence test. Phys Med Biol 2016; 61:8340-8359. [PMID: 27811392 DOI: 10.1088/0031-9155/61/23/8340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Multi-leaf collimators (MLCs) ensure the accurate delivery of treatments requiring complex beam fluences like intensity modulated radiotherapy and volumetric modulated arc therapy. The purpose of this work is to automate the detection of MLC relative position errors ⩾0.5 mm using electronic portal imaging device-based picket fence tests and compare the results to the qualitative assessment currently in use. Picket fence tests with and without intentional MLC errors were measured weekly on three Varian linacs. The picket fence images analysed covered a time period ranging between 14-20 months depending on the linac. An algorithm was developed that calculated the MLC error for each leaf-pair present in the picket fence images. The baseline error distributions of each linac were characterised for an initial period of 6 months and compared with the intentional MLC errors using statistical metrics. The distributions of median and one-sample Kolmogorov-Smirnov test p-value exhibited no overlap between baseline and intentional errors and were used retrospectively to automatically detect MLC errors in routine clinical practice. Agreement was found between the MLC errors detected by the automatic method and the fault reports during clinical use, as well as interventions for MLC repair and calibration. In conclusion the method presented provides for full automation of MLC quality assurance, based on individual linac performance characteristics. The use of the automatic method has been shown to provide early warning for MLC errors that resulted in clinical downtime.
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Affiliation(s)
- Damianos Christophides
- Radiotherapy Physics, Level 1 Bexley Wing, St. James's Institute of Oncology, Beckett Street, Leeds LS9 7TF, UK. University of Leeds, Leeds Institute of Cancer and Pathology, Leeds, UK
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35
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Izewska J, Wesolowska P, Azangwe G, Followill DS, Thwaites DI, Arib M, Stefanic A, Viegas C, Suming L, Ekendahl D, Bulski W, Georg D. Testing the methodology for dosimetry audit of heterogeneity corrections and small MLC-shaped fields: Results of IAEA multi-center studies. Acta Oncol 2016; 55:909-16. [PMID: 26934916 PMCID: PMC4926790 DOI: 10.3109/0284186x.2016.1139180] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The International Atomic Energy Agency (IAEA) has a long tradition of supporting development of methodologies for national networks providing quality audits in radiotherapy. A series of co-ordinated research projects (CRPs) has been conducted by the IAEA since 1995 assisting national external audit groups developing national audit programs. The CRP ‘Development of Quality Audits for Radiotherapy Dosimetry for Complex Treatment Techniques’ was conducted in 2009–2012 as an extension of previously developed audit programs. Material and methods. The CRP work described in this paper focused on developing and testing two steps of dosimetry audit: verification of heterogeneity corrections, and treatment planning system (TPS) modeling of small MLC fields, which are important for the initial stages of complex radiation treatments, such as IMRT. The project involved development of a new solid slab phantom with heterogeneities containing special measurement inserts for thermoluminescent dosimeters (TLD) and radiochromic films. The phantom and the audit methodology has been developed at the IAEA and tested in multi-center studies involving the CRP participants. Results. The results of multi-center testing of methodology for two steps of dosimetry audit show that the design of audit procedures is adequate and the methodology is feasible for meeting the audit objectives. A total of 97% TLD results in heterogeneity situations obtained in the study were within 3% and all results within 5% agreement with the TPS predicted doses. In contrast, only 64% small beam profiles were within 3 mm agreement between the TPS calculated and film measured doses. Film dosimetry results have highlighted some limitations in TPS modeling of small beam profiles in the direction of MLC leave movements. Discussion. Through multi-center testing, any challenges or difficulties in the proposed audit methodology were identified, and the methodology improved. Using the experience of these studies, the participants could incorporate the auditing procedures in their national programs.
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Affiliation(s)
| | | | | | | | | | - Mehenna Arib
- Centre De Recherche Nucleaire D’alger, Alger Gare, Algeria
| | | | | | - Luo Suming
- Chinese Centre for Disease Control and Prevention, Beijing, China
| | | | - Wojciech Bulski
- Maria Sklodowska-Curie Memorial Cancer Centre and Institute of Oncology, Warsaw, Poland
| | - Dietmar Georg
- Medical University of Vienna, Vienna, Austria
- Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Vienna, Austria
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Huq MS, Fraass BA, Dunscombe PB, Gibbons JP, Ibbott GS, Mundt AJ, Mutic S, Palta JR, Rath F, Thomadsen BR, Williamson JF, Yorke ED. The report of Task Group 100 of the AAPM: Application of risk analysis methods to radiation therapy quality management. Med Phys 2016; 43:4209. [PMID: 27370140 PMCID: PMC4985013 DOI: 10.1118/1.4947547] [Citation(s) in RCA: 298] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 03/13/2016] [Accepted: 03/14/2016] [Indexed: 12/25/2022] Open
Abstract
The increasing complexity of modern radiation therapy planning and delivery challenges traditional prescriptive quality management (QM) methods, such as many of those included in guidelines published by organizations such as the AAPM, ASTRO, ACR, ESTRO, and IAEA. These prescriptive guidelines have traditionally focused on monitoring all aspects of the functional performance of radiotherapy (RT) equipment by comparing parameters against tolerances set at strict but achievable values. Many errors that occur in radiation oncology are not due to failures in devices and software; rather they are failures in workflow and process. A systematic understanding of the likelihood and clinical impact of possible failures throughout a course of radiotherapy is needed to direct limit QM resources efficiently to produce maximum safety and quality of patient care. Task Group 100 of the AAPM has taken a broad view of these issues and has developed a framework for designing QM activities, based on estimates of the probability of identified failures and their clinical outcome through the RT planning and delivery process. The Task Group has chosen a specific radiotherapy process required for "intensity modulated radiation therapy (IMRT)" as a case study. The goal of this work is to apply modern risk-based analysis techniques to this complex RT process in order to demonstrate to the RT community that such techniques may help identify more effective and efficient ways to enhance the safety and quality of our treatment processes. The task group generated by consensus an example quality management program strategy for the IMRT process performed at the institution of one of the authors. This report describes the methodology and nomenclature developed, presents the process maps, FMEAs, fault trees, and QM programs developed, and makes suggestions on how this information could be used in the clinic. The development and implementation of risk-assessment techniques will make radiation therapy safer and more efficient.
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Affiliation(s)
- M Saiful Huq
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute and UPMC CancerCenter, Pittsburgh, Pennsylvania 15232
| | - Benedick A Fraass
- Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California 90048
| | - Peter B Dunscombe
- Department of Oncology, University of Calgary, Calgary T2N 1N4, Canada
| | | | - Geoffrey S Ibbott
- Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, Texas 77030
| | - Arno J Mundt
- Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California 92093-0843
| | - Sasa Mutic
- Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jatinder R Palta
- Department of Radiation Oncology, Virginia Commonwealth University, P.O. Box 980058, Richmond, Virginia 23298
| | - Frank Rath
- Department of Engineering Professional Development, University of Wisconsin, Madison, Wisconsin 53706
| | - Bruce R Thomadsen
- Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705-2275
| | - Jeffrey F Williamson
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia 23298-0058
| | - Ellen D Yorke
- Department of Medical Physics, Memorial Sloan-Kettering Center, New York, New York 10065
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Scaggion A, Negri A, Rossato M, Roggio A, Simonato F, Bacco S, Paiusco M. Delivering RapidArc®: A comprehensive study on accuracy and long term stability. Phys Med 2016; 32:866-73. [DOI: 10.1016/j.ejmp.2016.05.056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 05/16/2016] [Accepted: 05/19/2016] [Indexed: 10/21/2022] Open
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Carlson JNK, Park JM, Park SY, Park JI, Choi Y, Ye SJ. A machine learning approach to the accurate prediction of multi-leaf collimator positional errors. Phys Med Biol 2016; 61:2514-31. [PMID: 26948678 DOI: 10.1088/0031-9155/61/6/2514] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Discrepancies between planned and delivered movements of multi-leaf collimators (MLCs) are an important source of errors in dose distributions during radiotherapy. In this work we used machine learning techniques to train models to predict these discrepancies, assessed the accuracy of the model predictions, and examined the impact these errors have on quality assurance (QA) procedures and dosimetry. Predictive leaf motion parameters for the models were calculated from the plan files, such as leaf position and velocity, whether the leaf was moving towards or away from the isocenter of the MLC, and many others. Differences in positions between synchronized DICOM-RT planning files and DynaLog files reported during QA delivery were used as a target response for training of the models. The final model is capable of predicting MLC positions during delivery to a high degree of accuracy. For moving MLC leaves, predicted positions were shown to be significantly closer to delivered positions than were planned positions. By incorporating predicted positions into dose calculations in the TPS, increases were shown in gamma passing rates against measured dose distributions recorded during QA delivery. For instance, head and neck plans with 1%/2 mm gamma criteria had an average increase in passing rate of 4.17% (SD = 1.54%). This indicates that the inclusion of predictions during dose calculation leads to a more realistic representation of plan delivery. To assess impact on the patient, dose volumetric histograms (DVH) using delivered positions were calculated for comparison with planned and predicted DVHs. In all cases, predicted dose volumetric parameters were in closer agreement to the delivered parameters than were the planned parameters, particularly for organs at risk on the periphery of the treatment area. By incorporating the predicted positions into the TPS, the treatment planner is given a more realistic view of the dose distribution as it will truly be delivered to the patient.
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Affiliation(s)
- Joel N K Carlson
- Program in Biomedical Radiation Sciences, Department of Transdisciplinary Studies, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea. Biomedical Research Institute, Seoul National University Hospital, Seoul 03080, Korea
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Lebron S, Lu B, Yan G, Kahler D, Li JG, Barraclough B, Liu C. Parameterization of photon beam dosimetry for a linear accelerator. Med Phys 2016; 43:748-60. [PMID: 26843238 DOI: 10.1118/1.4939261] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In radiation therapy, accurate data acquisition of photon beam dosimetric quantities is important for (1) beam modeling data input into a treatment planning system (TPS), (2) comparing measured and TPS modeled data, (3) the quality assurance process of a linear accelerator's (Linac) beam characteristics, (4) the establishment of a standard data set for comparison with other data, etcetera. Parameterization of the photon beam dosimetry creates a data set that is portable and easy to implement for different applications such as those previously mentioned. The aim of this study is to develop methods to parameterize photon beam dosimetric quantities, including percentage depth doses (PDDs), profiles, and total scatter output factors (S(cp)). METHODS S(cp), PDDs, and profiles for different field sizes, depths, and energies were measured for a Linac using a cylindrical 3D water scanning system. All data were smoothed for the analysis and profile data were also centered, symmetrized, and geometrically scaled. The S(cp) data were analyzed using an exponential function. The inverse square factor was removed from the PDD data before modeling and the data were subsequently analyzed using exponential functions. For profile modeling, one halfside of the profile was divided into three regions described by exponential, sigmoid, and Gaussian equations. All of the analytical functions are field size, energy, depth, and, in the case of profiles, scan direction specific. The model's parameters were determined using the minimal amount of measured data necessary. The model's accuracy was evaluated via the calculation of absolute differences between the measured (processed) and calculated data in low gradient regions and distance-to-agreement analysis in high gradient regions. Finally, the results of dosimetric quantities obtained by the fitted models for a different machine were also assessed. RESULTS All of the differences in the PDDs' buildup and the profiles' penumbra regions were less than 2 and 0.5 mm, respectively. The differences in the low gradient regions were 0.20% ± 0.20% (<1% for all) and 0.50% ± 0.35% (<1% for all) for PDDs and profiles, respectively. For S(cp) data, all of the absolute differences were less than 0.5%. CONCLUSIONS This novel analytical model with minimum measurement requirements was proved to accurately calculate PDDs, profiles, and S(cp) for different field sizes, depths, and energies.
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Affiliation(s)
- Sharon Lebron
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385 and J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611
| | - Bo Lu
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385
| | - Guanghua Yan
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385
| | - Darren Kahler
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385
| | - Jonathan G Li
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385
| | - Brendan Barraclough
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385 and J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611
| | - Chihray Liu
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida 32610-0385
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Huang BT, Lin Z, Lin PX, Lu JY, Chen CZ. Monitor unit optimization in stereotactic body radiotherapy for small peripheral non-small cell lung cancer patients. Sci Rep 2015; 5:18453. [PMID: 26679747 PMCID: PMC4683452 DOI: 10.1038/srep18453] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 11/18/2015] [Indexed: 02/05/2023] Open
Abstract
The increasingly attractive stereotactic body radiotherapy (SBRT) treatment for stage I lung cancer is concomitant with a large amount of monitor units (MU), leading to excessive out-of-field dose and prolonged beam-on time. The study aims to reduce the MU number and shorten the beam-on time by optimizing the planning parameters. Clinically acceptable treatment plans from fourteen patients suffered from peripheral stage I non-small cell lung cancer (NSCLC) were created in the study. Priority for the upper objective of the target (PUOT), strength and Max MU setting in the MU objective function (MUOF) were adjusted respectively to investigate their effect on MU number, organs at risk (OARs) sparing and beam-on time. We found that the planning parameters influenced the MU number in a PUOT, strength and Max MU dependent manner. Combined with high priority for the UOT (HPUOT) and MUOF, the MU number was reduced from 443 ± 25 to 228 ± 22 MU/Gy without compromising the target coverage and OARs sparing. We also found beam-on time was proportional to MU number and it could be shortened from 7.9 ± 0.5 to 4.1 ± 0.4 minutes.
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Affiliation(s)
- Bao-Tian Huang
- Cancer Hospital of Shantou University Medical College, Department of Radiation Oncology, Shantou, 515031, China
| | - Zhu Lin
- Cancer Hospital of Shantou University Medical College, Department of Radiation Oncology, Shantou, 515031, China
| | - Pei-Xian Lin
- The Second Affiliated Hospital of Shantou University Medical College, Department of Nosocomial Infection Management, Shantou, 515041, China
| | - Jia-Yang Lu
- Cancer Hospital of Shantou University Medical College, Department of Radiation Oncology, Shantou, 515031, China
| | - Chuang-Zhen Chen
- Cancer Hospital of Shantou University Medical College, Department of Radiation Oncology, Shantou, 515031, China
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Nithiyanantham K, Mani GK, Subramani V, Mueller L, Palaniappan KK, Kataria T. Analysis of direct clinical consequences of MLC positional errors in volumetric-modulated arc therapy using 3D dosimetry system. J Appl Clin Med Phys 2015; 16:296–305. [PMID: 26699311 PMCID: PMC5690184 DOI: 10.1120/jacmp.v16i5.5515] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/06/2015] [Accepted: 04/28/2015] [Indexed: 01/04/2023] Open
Abstract
In advanced, intensity-modulated external radiotherapy facility, the multileaf collimator has a decisive role in the beam modulation by creating multiple segments or dynamically varying field shapes to deliver a uniform dose distribution to the target with maximum sparing of normal tissues. The position of each MLC leaf has become more critical for intensity-modulated delivery (step-and-shoot IMRT, dynamic IMRT, and VMAT) compared to 3D CRT, where it defines only field boundaries. We analyzed the impact of the MLC positional errors on the dose distribution for volumetric-modulated arc therapy, using a 3D dosimetry system. A total of 15 VMAT cases, five each for brain, head and neck, and prostate cases, were retrospectively selected for the study. All the plans were generated in Monaco 3.0.0v TPS (Elekta Corporation, Atlanta, GA) and delivered using Elekta Synergy linear accelerator. Systematic errors of +1, +0.5, +0.3, 0, -1, -0.5, -0.3 mm were introduced in the MLC bank of the linear accelerator and the impact on the dose distribution of VMAT delivery was measured using the COMPASS 3D dosim-etry system. All the plans were created using single modulated arcs and the dose calculation was performed using a Monte Carlo algorithm in a grid size of 3 mm. The clinical endpoints D95%, D50%, D2%, and Dmax,D20%, D50% were taken for the evaluation of the target and critical organs doses, respectively. A significant dosimetric effect was found for many cases even with 0.5 mm of MLC positional errors. The average change of dose D 95% to PTV for ± 1 mm, ± 0.5 mm, and ±0.3mm was 5.15%, 2.58%, and 0.96% for brain cases; 7.19%, 3.67%, and 1.56% for head and neck cases; and 8.39%, 4.5%, and 1.86% for prostate cases, respectively. The average deviation of dose Dmax was 5.4%, 2.8%, and 0.83% for brainstem in brain cases; 8.2%, 4.4%, and 1.9% for spinal cord in H&N; and 10.8%, 6.2%, and 2.1% for rectum in prostate cases, respectively. The average changes in dose followed a linear relationship with the amount of MLC positional error, as can be expected. MLC positional errors beyond ± 0.3 mm showed a significant influence on the intensity-modulated dose distributions. It is, therefore, recommended to have a cautious MLC calibration procedure to sufficiently meet the accuracy in dose delivery.
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Antypas C, Floros I, Rouchota M, Armpilia C, Lyra M. MLC positional accuracy evaluation through the Picket Fence test on EBT2 films and a 3D volumetric phantom. J Appl Clin Med Phys 2015; 16:5185. [PMID: 26103188 PMCID: PMC5690090 DOI: 10.1120/jacmp.v16i2.5185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 12/10/2014] [Accepted: 12/04/2014] [Indexed: 11/25/2022] Open
Abstract
The accuracy of MLC positions during radiotherapy is important as even small positional deviations can translate into considerable dose delivery errors. This becomes crucial when radiosensitive organs are located near the treated volume and especially during IMRT, where dose gradients are steep. A test commonly conducted to measure the positional accuracy of the MLCs is the Picket Fence test. In this study two alterations of the Picket Fence test were performed and evaluated, the first one using radiochromic EBT2 films and the second one the Delta4PT diode array phantom and its software. Our results showed that EBT2 films provide a relatively fast, qualitative visual inspection of the significant leaf dispositions. When slight inaccuracies need to be revealed or precise numerical results for each leaf position are needed, Delta4PT provides the desired accuracy of 1 mm. In treatment modalities where a higher accuracy is required in the delivered dose distribution, such as in IMRT, precise numerical values of the measurements for the MLC positional inspection are required. PACS number: 87.55.Qr, 87.56.bd, 87.56.Fc, 87.56.nk
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Affiliation(s)
- Christos Antypas
- 1st Department of Radiology, Medical Physics Unit, Aretaieion Hospital, University of Athens.
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Kerns JR, Childress N, Kry SF. A multi-institution evaluation of MLC log files and performance in IMRT delivery. Radiat Oncol 2014; 9:176. [PMID: 25112533 PMCID: PMC4251954 DOI: 10.1186/1748-717x-9-176] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 07/21/2014] [Indexed: 11/24/2022] Open
Abstract
Background The multileaf collimator (MLC) is a critical component to accurate intensity-modulated radiotherapy (IMRT) delivery. This study examined MLC positional accuracy via MLC logs from Varian machines from six institutions and three delivery techniques to evaluate typical positional accuracy and treatment and mechanical parameters that affect accuracy. Typical accuracy achieved was compared against TG-142 recommendations for MLC performance; more appropriate recommendations are suggested. Methods Over 85,000 Varian MLC treatment logs were collected from six institutions and analyzed with FractionCHECK. Data were binned according to institution and treatment type to determine overall root mean square (RMS) and 95th percentile error values, and then to look for correlations between those errors and with mechanical and treatment parameters including mean and maximum leaf speed, gantry angle, beam-on time, mean leaf error, and number of segments. Results Results of treatment logs found that leaf RMS error and 95th percentile leaf error were consistent between institutions, but varied by treatment type. The step and shoot technique had very small errors: the mean RMS leaf error was 0.008 mm. For dynamic treatments the mean RMS leaf error was 0.32 mm, while volumetric-modulated arc treatment (VMAT) showed an RMS leaf error of 0.46 mm. Most MLC leaf errors were found to be well below TG-142 recommended tolerances. For the dynamic and VMAT techniques, the mean and maximum leaf speeds were significantly linked to the leaf RMS error. Additionally, for dynamic delivery, the mean leaf error was correlated with RMS error, whereas for VMAT the average gantry speed was correlated. For all treatments, the RMS error and the 95th percentile leaf error were correlated. Conclusions Restricting the maximum leaf speed can help improve MLC performance for dynamic and VMAT deliveries. Furthermore, the tolerances of leaf RMS and error counts for all treatment types should be tightened from the TG-142 values to make them more appropriate for clinical performance. Values of 1 mm for the 95th percentile of leaf RMS error and 1.5 mm for the 95th percentile leaf error are suggested as action levels for all treatment types.
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Affiliation(s)
- James R Kerns
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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Manikandan A, Sarkar B, Nandy M, Sureka CS, Gossman MS, Sujatha N, Rajendran VT. Detector system dose verification comparisons for arc therapy: couch vs. gantry mount. J Appl Clin Med Phys 2014; 15:4495. [PMID: 24892330 PMCID: PMC5711059 DOI: 10.1120/jacmp.v15i3.4495] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 12/11/2013] [Accepted: 01/04/2014] [Indexed: 11/29/2022] Open
Abstract
The aim of this study was to assess the performance of a gantry‐mounted detector system and a couch set detector system using a systematic multileaf collimator positional error manually introduced for volumetric‐modulated arc therapy. Four head and neck and esophagus VMAT plans were evaluated by measurement using an electronic portal imaging device and an ion chamber array. Each plan was copied and duplicated with a 1 mm systematic MLC positional error in the left leaf bank. Direct comparison of measurements for plans with and without the error permitted observational characteristics for quality assurance performance between detectors. A total of 48 different plans were evaluated for this testing. The mean percentage planar dose differences required to satisfy a 95% match between plans with and without the MLCPE were 5.2% ± 0.5% for the chamber array with gantry motion, 8.12% ± 1.04% for the chamber array with a static gantry at 0°, and 10.9% ± 1.4% for the EPID with gantry motion. It was observed that the EPID was less accurate due to overresponse of the MLCPE in the left leaf bank. The EPID always images bank‐A on the ipsilateral side of the detector, whereas for a chamber array or for a patient, that bank changes as it crosses the ‐90° or +90° position. A couch set detector system can reproduce the TPS calculated values most consistently. We recommend it as the most reliable patient specific QA system for MLC position error testing. This research is highlighted by the finding of up to 12.7% dose variation for H/N and esophagus cases for VMAT delivery, where the mere source of error was the stated clinically acceptability of 1 mm MLC position deviation of TG‐142. PACS numbers: 87.56.‐v, 87.55.‐x, 07.57.KP, 29.40.‐n, 85.25.Pb
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Bai S, Li G, Wang M, Jiang Q, Zhang Y, Wei Y. Effect of MLC leaf position, collimator rotation angle, and gantry rotation angle errors on intensity-modulated radiotherapy plans for nasopharyngeal carcinoma. Med Dosim 2013; 38:143-7. [DOI: 10.1016/j.meddos.2012.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 09/12/2012] [Accepted: 10/25/2012] [Indexed: 10/27/2022]
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Zhen H, Nelms BE, Tomé WA. On the use of biomathematical models in patient-specific IMRT dose QA. Med Phys 2013; 40:071702. [DOI: 10.1118/1.4805105] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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47
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Heilemann G, Poppe B, Laub W. On the sensitivity of common gamma-index evaluation methods to MLC misalignments in Rapidarc quality assurance. Med Phys 2013; 40:031702. [DOI: 10.1118/1.4789580] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Betzel GT, Yi BY, Niu Y, Yu CX. Is RapidArc more susceptible to delivery uncertainties than dynamic IMRT? Med Phys 2012; 39:5882-90. [PMID: 23039627 DOI: 10.1118/1.4749965] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Rotational IMRT has been adopted by many clinics for its promise to deliver treatments in a shorter amount of time than other conventional IMRT techniques. In this paper, the authors investigate whether RapidArc is more susceptible to delivery uncertainties than dynamic IMRT using fixed fields. METHODS Dosimetric effects of delivery uncertainties in dose rate, gantry angle, and MLC leaf positions were evaluated by incorporating these uncertainties into RapidArc and sliding window IMRT (SW IMRT) treatment plans for five head-and-neck and five prostate cases. Dose distributions and dose-volume histograms of original and modified plans were recalculated and compared using Gamma analysis and dose indices of planned treatment volumes (PTV) and organs at risk (OAR). Results of Gamma analyses using passing criteria ranging from 1%-1 mm up to 5%-3 mm were reported. RESULTS Systematic shifts in MLC leaf bank positions of SW-IMRT cases resulted in 2-4 times higher average percent differences than RapidArc cases. Uniformly distributed random variations of 2 mm for active MLC leaves had a negligible effect on all dose distributions. Sliding window cases were much more sensitive to systematic shifts in gantry angle. Dose rate variations during RapidArc must be much larger than typical machine tolerances to affect dose distributions significantly; dynamic IMRT is inherently not susceptible to such variations. CONCLUSIONS RapidArc deliveries were found to be more tolerant to variations in gantry position and MLC leaf position than SW IMRT. This may be attributed to the fact that the average segmental field size or MLC leaf opening is much larger for RapidArc. Clinically acceptable treatments may be delivered successfully using RapidArc despite large fluctuations in dose rate and gantry position.
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Affiliation(s)
- Gregory T Betzel
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
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Tatsumi D, Nakada R, Ienaga A, Yomoda A, Inoue M, Ichida T, Hosono M. [Positional accuracy and quality assurance of Backup JAWs required for volumetric modulated arc therapy]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2012; 68:1486-91. [PMID: 23171770 DOI: 10.6009/jjrt.2012_jsrt_68.11.1486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The tolerance of the Backup diaphragm (Backup JAW) setting in Elekta linac was specified as 2 mm according to the AAPM TG-142 report. However, the tolerance and the quality assurance procedure for volumetric modulated arc therapy (VMAT) was not provided. This paper describes positional accuracy and quality assurance procedure of the Backup JAWs required for VMAT. It was found that a gap-width error of the Backup JAW by a sliding window test needed to be less than 1.5 mm for prostate VMAT delivery. It was also confirmed that the gap-widths had been maintained with an error of 0.2 mm during the past one year.
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Park JY, Lee JW, Chung JB, Choi KS, Kim YL, Park BM, Kim Y, Kim J, Choi J, Kim JS, Hong S, Suh TS. Radiobiological model-based bio-anatomical quality assurance in intensity-modulated radiation therapy for prostate cancer. JOURNAL OF RADIATION RESEARCH 2012; 53:978-988. [PMID: 22915778 PMCID: PMC3483850 DOI: 10.1093/jrr/rrs049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 06/11/2012] [Accepted: 06/12/2012] [Indexed: 06/01/2023]
Abstract
A bio-anatomical quality assurance (QA) method employing tumor control probability (TCP) and normal tissue complication probability (NTCP) is described that can integrate radiobiological effects into intensity-modulated radiation therapy (IMRT). We evaluated the variations in the radiobiological effects caused by random errors (r-errors) and systematic errors (s-errors) by evaluating TCP and NTCP in two groups: patients with an intact prostate (G(intact)) and those who have undergone prostatectomy (G(tectomy)). The r-errors were generated using an isocenter shift of ±1 mm to simulate a misaligned patient set-up. The s-errors were generated using individual leaves that were displaced inwardly and outwardly by 1 mm on multileaf collimator field files. Subvolume-based TCP and NTCP were visualized on computed tomography (CT) images to determine the radiobiological effects on the principal structures. The bio-anatomical QA using the TCP and NTCP maps differentiated the critical radiobiological effects on specific volumes, particularly at the anterior rectal walls and planning target volumes. The s-errors showed a TCP variation of -40-25% in G(tectomy) and -30-10% in G(intact), while the r-errors were less than 1.5% in both groups. The r-errors for the rectum and bladder showed higher NTCP variations at ±20% and ±10%, respectively, and the s-errors were greater than ±65% for both. This bio-anatomical method, as a patient-specific IMRT QA, can provide distinct indications of clinically significant radiobiological effects beyond the minimization of probable physical dose errors in phantoms.
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Affiliation(s)
- Ji-Yeon Park
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
- Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul 137-701, Korea
| | - Jeong-Woo Lee
- Research Institute of Health Science, College of Health Science, Korea University, Seoul 136-703, Korea
- Department of Radiation Oncology, Konkuk University Medical Center, Seoul 143-729, Korea
| | - Jin-Beom Chung
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam 463-707, Korea
| | - Kyoung-Sik Choi
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
- Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul 137-701, Korea
- Department of Radiation Oncology, Anyang SAM Hospital, Anyang 430-733, Korea
| | - Yon-Lae Kim
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
- Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul 137-701, Korea
- Department of Radiology, Choonhae College of Health Science, Ulsan 689-784, Korea
| | - Byung-Moon Park
- Department of Radiation Oncology, Konkuk University Medical Center, Seoul 143-729, Korea
| | - Youhyun Kim
- Department of Radiologic Science, College of Health Science, Korea University, Seoul 136-703, Korea
| | - Jungmin Kim
- Department of Radiologic Science, College of Health Science, Korea University, Seoul 136-703, Korea
| | - Jonghak Choi
- Department of Radiologic Science, College of Health Science, Korea University, Seoul 136-703, Korea
| | - Jae-Sung Kim
- Department of Radiation Oncology, Seoul National University Bundang Hospital, Seongnam 463-707, Korea
| | - Semie Hong
- Department of Radiation Oncology, Konkuk University Medical Center, Seoul 143-729, Korea
| | - Tae-Suk Suh
- Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
- Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul 137-701, Korea
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