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Pant A, Miri N, Bhagroo S, Mathews JA, Nazareth DP. Monitor unit verification for Varian TrueBeam VMAT plans using Monte Carlo calculations and phase space data. J Appl Clin Med Phys 2023; 24:e14063. [PMID: 37469244 PMCID: PMC10562028 DOI: 10.1002/acm2.14063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 04/29/2023] [Accepted: 05/15/2023] [Indexed: 07/21/2023] Open
Abstract
To use the open-source Monte Carlo (MC) software calculations for TPS monitor unit verification of VMAT plans, delivered with the Varian TrueBeam linear accelerator, and compare the results with a commercial software product, following the guidelines set in AAPM Task Group 219. The TrueBeam is modeled in EGSnrc using the Varian-provided phase-space files. Thirteen VMAT TrueBeam treatment plans representing various anatomical regions were evaluated, comprising 37 treatment arcs. VMAT plans simulations were performed on a computing cluster, using 107 -109 particle histories per arc. Point dose differences at five reference points per arc were compared between Eclipse, MC, and the commercial software, MUCheck. MC simulation with 5 × 107 histories per arc offered good agreement with Eclipse and a reasonable average calculation time of 9-18 min per full plan. The average absolute difference was 3.0%, with only 22% of all points exceeding the 5% action limit. In contrast, the MUCheck average absolute difference was 8.4%, with 60% of points exceeding the 5% dose difference. Lung plans were particularly problematic for MUCheck, with an average absolute difference of approximately 16%. Our EGSnrc-based MC framework can be used for the MU verification of VMAT plans calculated for the Varian TrueBeam; furthermore, our phase space approach can be adapted to other treatment devices by using appropriate phase space files. The use of 5 × 107 histories consistently satisfied the 5% action limit across all plan types for the majority of points, performing significantly better than a commercial MU verification system, MUCheck. As faster processors and cloud computing facilities become even more widely available, this approach can be readily implemented in clinical settings.
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Affiliation(s)
- Ankit Pant
- Department of Radiation MedicineRoswell Park Comprehensive Cancer CenterBuffaloNew YorkUSA
- Medical Physics ProgramUniversity at Buffalo (SUNY)BuffaloNew YorkUSA
| | - Narges Miri
- Department of Radiation MedicineRoswell Park Comprehensive Cancer CenterBuffaloNew YorkUSA
| | - Stephen Bhagroo
- Department of Radiation OncologyHuntsman Cancer InstituteSalt Lake CityUtahUSA
| | | | - Daryl P. Nazareth
- Department of Radiation MedicineRoswell Park Comprehensive Cancer CenterBuffaloNew YorkUSA
- Medical Physics ProgramUniversity at Buffalo (SUNY)BuffaloNew YorkUSA
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Kubo K, Tamura M, Matsumoto K, Otsuka M, Monzen H. Independent monitor unit verification for dynamic flattened beam plans on the Halcyon linac. J Appl Clin Med Phys 2022; 24:e13807. [PMID: 36265085 PMCID: PMC9859998 DOI: 10.1002/acm2.13807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 08/17/2022] [Accepted: 09/22/2022] [Indexed: 01/26/2023] Open
Abstract
Independent monitor unit verification (MUV) methods for the dynamic beam-flattening (DBF) technique have not been established. The purpose of this study was to clarify whether MU values for the DBF technique can be calculated using in-air and in-water output ratios (Sc and Scp ). Sc and Scp were measured in the DBF mode, and the phantom scatter factor (Sp ) was calculated. The difference between calculated and planned MUs with square and rectangle fields and clinical plans for different treatment sites was also evaluated. Sc values for the 4 × 4 to 24 × 24 cm2 fields of the distal multi-leaf collimator (MLC) layer at 2-cm intervals were 0.887, 0.815, 0.715, 0.716, 0.611, 0.612, 0.511, 0.373, 0.374, 0.375, and 0.374, respectively. No collimator exchange effect was observed. Sc also depends slightly on the field size of the distal MLC layer. If the distal-MLC-layered field size was less than 20% of the corresponding MLC sequence size in the proximal MLC layer, Sc was affected by >1%, which was compensated using a correction factor (CF). Sp increased as the field sizes of the MLC sequence and distal MLC leaves increased. MUs calculated using measured Sc , Sp , and CF for square and rectangle fields agreed with planned MUs within ±1.2%. A larger difference (-1.5%) between calculated and planned MUs was observed for clinical plans, whereas differences in MUs were within 2 MU for most fields (56 out of 64 fields). MU calculation for the DBF technique can be performed with Sc , Sp , and CF for independent MUV.
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Affiliation(s)
- Kazuki Kubo
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsaka‐sayamaOsakaJapan
| | - Mikoto Tamura
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsaka‐sayamaOsakaJapan
| | - Kenji Matsumoto
- Department of Radiology CenterKindai University HospitalOsaka‐sayamaOsakaJapan
| | - Masakazu Otsuka
- Department of Radiology CenterKindai University HospitalOsaka‐sayamaOsakaJapan
| | - Hajime Monzen
- Department of Medical PhysicsGraduate School of Medical SciencesKindai UniversityOsaka‐sayamaOsakaJapan
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Comparison of an in-house developed monitor unit double-check program for 3D conformal radiation therapy and treatment planning system verification. JOURNAL OF RADIOTHERAPY IN PRACTICE 2019. [DOI: 10.1017/s1460396918000742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractAimThe treatment planning system (TPS) plays a key role in radiotherapy treatments; it is responsible for the accurate determination of the monitor unit (MU) needed to be delivered to treat a patient with cancer. The main goal of radiotherapy is to sterilise the tumour; however, any imprecise dose delivered could lead to deadly consequences. The TPS has a quality assurance tool, an independent program to double check the MU, evaluate patient plan correctness and search for any potential error.Materials and methodsIn this work, a comparison was carried out between a MU calculated by TPS and an independent in-house-developed monitor unit calculation program (MUCP). The program, written in Cplusplus (C++ Object-Oriented), requires a database of several measured quantities and uses a recently developed physically based method for field equivalence calculation. The ROOT CERN data analysis library has been used to establish fit functions, to extend MUCP use to a variety of photon beams. This study presents a new approach to checking MU correctness calculated by the TPS for a water-like tissue equivalent medium, using our MUCP, as the majority of previous studies on the MU independent checks were based on the Clarkson method. To evaluate each irradiated region, four calculation points corresponding to relative depths under the water phantom were tested for several symmetric, asymmetric, irregular symmetric and asymmetric field cases. A comparison of MU for each radiation fields from readings of the TPS and the MUCP was undertaken.ResultsA satisfactory agreement has been obtained and within the required standards (3%). Additional experimental measurements of dose deposited in a water phantom showed a deviation of <1·6%.FindingsThe MUCP is a useful tool for basic and complex MU verification for 3D conformal radiation therapy plans.
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Bhagroo S, French SB, Mathews JA, Nazareth DP. Secondary monitor unit calculations for VMAT using parallelized Monte Carlo simulations. J Appl Clin Med Phys 2019; 20:60-69. [PMID: 31127699 PMCID: PMC6560245 DOI: 10.1002/acm2.12605] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/01/2022] Open
Abstract
We have developed a fast and accurate in‐house Monte Carlo (MC) secondary monitor unit (MU) check method, based on the EGSnrc system, for independent verification of volumetric modulated arc therapy (VMAT) treatment planning system dose calculations, in accordance with TG‐114 recommendations. For a VMAT treatment plan created for a Varian Trilogy linac, DICOM information was exported from Eclipse. An open‐source platform was used to generate input files for dose calculations using the EGSnrc framework. The full VMAT plan simulation employed 107 histories, and was parallelized to run on a computer cluster. The resulting 3ddose matrices were converted to the DICOM format using CERR and imported into Eclipse. The method was evaluated using 35 clinical VMAT plans of various treatment sites. For each plan, the doses calculated with the MC approach at four three‐dimensional reference points were compared to the corresponding Eclipse calculations, as well as calculations performed using the clinical software package, MUCheck. Each MC arc simulation of 107 particles required 13–25 min of total time, including processing and calculation. The average discrepancies in calculated dose values between the MC method and Eclipse were 2.03% (compared to 3.43% for MUCheck) for prostate cases, 2.45% (3.22% for MUCheck) for head and neck cases, 1.7% (5.51% for MUCheck) for brain cases, and 2.84% (5.64% for MUCheck) for miscellaneous cases. Of 276 comparisons, 201 showed greater agreement between the treatment planning system and MC vs MUCheck. The largest discrepancies between MC and MUCheck were found in regions of high dose gradients and heterogeneous densities. By parallelizing the calculations, point‐dose accuracies of 2‐7%, sufficient for clinical secondary checks, can be achieved in a reasonable amount of time. As computer clusters and/or cloud computing become more widespread, this method will be useful in most clinical setups.
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Affiliation(s)
- Stephen Bhagroo
- Department of Radiation Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.,Medical Physics Program, University at Buffalo (SUNY), Buffalo, NY, USA
| | - Samuel B French
- Department of Radiation Oncology, Piedmont Healthcare, Atlanta, GA, USA.,Medical Physics Program, University at Buffalo (SUNY), Buffalo, NY, USA
| | - Joshua A Mathews
- Department of Radiation Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.,Medical Physics Program, University at Buffalo (SUNY), Buffalo, NY, USA
| | - Daryl P Nazareth
- Department of Radiation Medicine, Roswell Park Comprehensive Cancer Center, Buffalo, NY, USA.,Medical Physics Program, University at Buffalo (SUNY), Buffalo, NY, USA
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Tachibana H, Uchida Y, Miyakawa R, Yamashita M, Sato A, Kito S, Maruyama D, Noda S, Kojima T, Fukuma H, Shirata R, Okamoto H, Nakamura M, Takada Y, Nagata H, Hayashi N, Takahashi R, Kawai D, Itano M. Multi-institutional comparison of secondary check of treatment planning using computer-based independent dose calculation for non-C-arm linear accelerators. Phys Med 2018; 56:58-65. [PMID: 30527090 DOI: 10.1016/j.ejmp.2018.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 08/31/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022] Open
Abstract
PURPOSE This report covers the first multi-institutional study of independent monitor unit (MU)/dose calculation verification for the CyberKnife, Vero4DRT, and TomoTherapy radiotherapy delivery systems. METHODS A total of 973 clinical treatment plans were collected from 12 institutions. Commercial software employing the Clarkson algorithm was used for verification after a measurement validation study, and the doses from the treatment planning systems (TPSs) and verification programs were compared on the basis of the mean value ± two standard deviations. The impact of heterogeneous conditions was assessed in two types of sites: non-lung and lung. RESULTS The dose difference for all locations was 0.5 ± 7.2%. There was a statistically significant difference (P < 0.01) in dose difference between non-lung (-0.3 ± 4.4%) and lung sites (3.5 ± 6.7%). Inter-institutional comparisons showed that various systematic differences were associated with the proportion of different treatment sites and heterogeneity correction. CONCLUSIONS This multi-institutional comparison should help to determine the departmental action levels for CyberKnife, Vero4DRT, and TomoTherapy, as patient populations and treatment sites may vary between the modalities. An action level of ±5% could be considered for intensity-modulated radiation therapy (IMRT), non-IMRT, and volumetric modulated arc radiotherapy using these modalities in homogenous and heterogeneous conditions with a large treatment field applied to a large region of homogeneous media. There were larger systematic differences in heterogeneous conditions with a small treatment field because of differences in heterogeneity correction with the different dose calculation algorithms of the primary TPS and verification program.
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Affiliation(s)
- Hidenobu Tachibana
- Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 277-8577 Chiba, Japan; Radiation Safety and Quality Assurance Division, Hospital East, National Cancer Center, 277-8577 Chiba, Japan.
| | - Yukihiro Uchida
- Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 277-8577 Chiba, Japan.
| | - Ryuta Miyakawa
- Department of Radiology, Saiseikai Yokohamashi Tobu Hospital, 230-8765 Kanagawa, Japan.
| | - Mikiko Yamashita
- Department of Radiological Technology, Kobe City Medical Center General Hospital, 650-0047 Hyogo, Japan.
| | - Aya Sato
- Department of Radiology, Itabashi Chuo Medical Center, 174-0051 Tokyo, Japan
| | - Satoshi Kito
- Department of Radiation Oncology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 113-8677 Tokyo, Japan.
| | - Daiki Maruyama
- Department of Medical Technology, Japanese Red Cross Medical Center, 150-8935 Tokyo, Japan.
| | - Shigetoshi Noda
- Department of Radiology, Kitasato University Hospital, 252-0375 Kanagawa, Japan.
| | - Toru Kojima
- Department of Radiation Oncology, Saitama Cancer Center, 362-0806 Saitama, Japan
| | - Hiroshi Fukuma
- Department of Radiology, Nagoya City University Hospital, 467-8602 Aichi, Japan
| | - Ryosuke Shirata
- Department of Radiation Oncology, Shonan Kamakura General Hospital, 247-8533 Kanagawa, Japan.
| | - Hiroyuki Okamoto
- Department of Radiation Oncology, The National Cancer Center, 104-0045 Tokyo, Japan.
| | - Mitsuhiro Nakamura
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 606-8507 Kyoto, Japan.
| | - Yuma Takada
- Department of Radiology, Ogaki Tokushukai Hospital, 503-0015 Gifu, Japan.
| | - Hironori Nagata
- Department of Radiation Oncology, Shonan Kamakura General Hospital, 247-8533 Kanagawa, Japan
| | - Naoki Hayashi
- School of Health Sciences, Fujita Health University, 470-1192 Aichi, Japan.
| | - Ryo Takahashi
- Department of Radiation Oncology, The Cancer Institute Hospital of Japanese Foundation of Cancer Research, 135-8550 Tokyo, Japan.
| | - Daisuke Kawai
- Division of Radiation Oncology, Kanagawa Cancer Center, 241-0815 Kanagawa, Japan
| | - Masanobu Itano
- Department of Radiation Oncology, Funabashi Municipal Medical Center, 273-8588 Chiba, Japan.
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