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Carpentier EE, Mcdermott RL, Su S, Rostamzadeh M, Popescu IA, Bergman AM, Mestrovic A. Monte Carlo Modeling of Dynamic Tumor Tracking on a Gimbaled Linear Accelerator. J Med Phys 2023; 48:50-58. [PMID: 37342609 PMCID: PMC10277301 DOI: 10.4103/jmp.jmp_108_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/19/2023] [Accepted: 02/11/2023] [Indexed: 06/23/2023] Open
Abstract
Purpose and Aim The Vero4DRT (Brainlab AG) linear accelerator is capable of dynamic tumor tracking (DTT) by panning/tilting the radiation beam to follow respiratory-induced tumor motion in real time. In this study, the panning/tilting motion is modeled in Monte Carlo (MC) for quality assurance (QA) of four-dimensional (4D) dose distributions created within the treatment planning system (TPS). Materials and Methods Step-and-shoot intensity-modulated radiation therapy plans were optimized for 10 previously treated liver patients. These plans were recalculated on multiple phases of a 4D computed tomography (4DCT) scan using MC while modeling panning/tilting. The dose distributions on each phase were accumulated to create a respiratory-weighted 4D dose distribution. Differences between the TPS and MC modeled doses were examined. Results On average, 4D dose calculations in MC showed the maximum dose of an organ at risk (OAR) to be 10% greater than the TPS' three-dimensional dose calculation (collapsed cone [CC] convolution algorithm) predicted. MC's 4D dose calculations showed that 6 out of 24 OARs could exceed their specified dose limits, and calculated their maximum dose to be 4% higher on average (up to 13%) than the TPS' 4D dose calculations. Dose differences between MC and the TPS were greatest in the beam penumbra region. Conclusion Modeling panning/tilting for DTT has been successfully modeled with MC and is a useful tool to QA respiratory-correlated 4D dose distributions. The dose differences between the TPS and MC calculations highlight the importance of using 4D MC to confirm the safety of OAR doses before DTT treatments.
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Affiliation(s)
- Emilie E. Carpentier
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Medical Physics, BC Cancer, Vancouver, BC, Canada
| | | | - Shiqin Su
- Department of Medical Physics, BC Cancer, Vancouver, BC, Canada
| | - Maryam Rostamzadeh
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Medical Physics, BC Cancer, Vancouver, BC, Canada
| | - I. Antoniu Popescu
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
- Department of Medical Physics, BC Cancer, Vancouver, BC, Canada
| | | | - Ante Mestrovic
- Department of Medical Physics, BC Cancer, Vancouver, BC, Canada
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Paoletti L, Ceccarelli C, Menichelli C, Aristei C, Borghesi S, Tucci E, Bastiani P, Cozzi S. Special stereotactic radiotherapy techniques: procedures and equipment for treatment simulation and dose delivery. Rep Pract Oncol Radiother 2022; 27:1-9. [PMID: 35402024 PMCID: PMC8989452 DOI: 10.5603/rpor.a2021.0129] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/14/2021] [Indexed: 12/25/2022] Open
Abstract
Stereotactic radiotherapy (SRT ) is a multi-step procedure with each step requiring extreme accuracy. Physician-dependent accuracy includes appropriate disease staging, multi-disciplinary discussion with shared decision-making, choice of morphological and functional imaging methods to identify and delineate the tumor target and organs at risk, an image-guided patient set-up, active or passive management of intra-fraction movement, clinical and instrumental follow-up. Medical physicist-dependent accuracy includes use of advanced software for treatment planning and more advanced Quality Assurance procedures than required for conventional radiotherapy. Consequently, all the professionals require appropriate training in skills for high-quality SRT. Thanks to the technological advances, SRT has moved from a “frame-based” technique, i.e. the use of stereotactic coordinates which are identified by means of rigid localization frames, to the modern “frame-less” SRT which localizes the target volume directly, or by means of anatomical surrogates or fiducial markers that have previously been placed within or near the target. This review describes all the SRT steps in depth, from target simulation and delineation procedures to treatment delivery and image-guided radiation therapy. Target movement assessment and management are also described.
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Affiliation(s)
- Lisa Paoletti
- Radiotherapy Unit, AUSL Toscana Centro, Florence, Italy
| | | | | | - Cynthia Aristei
- Radiation Oncology Section, University of Perugia and Perugia General Hospital, Italy
| | - Simona Borghesi
- Radiation Oncology Unit of Arezzo-Valdarno, Azienda USL Toscana Sud Est, Italy
| | - Enrico Tucci
- Radiation Oncology Unit of Arezzo-Valdarno, Azienda USL Toscana Sud Est, Italy
| | | | - Salvatore Cozzi
- Radiation Oncology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Italy
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Treatment planning comparison between dynamic wave arc and volumetric modulated arc therapies for prostate-cancer treatment. Med Dosim 2021; 47:48-53. [PMID: 34538693 DOI: 10.1016/j.meddos.2021.08.001] [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: 05/09/2021] [Revised: 07/05/2021] [Accepted: 08/08/2021] [Indexed: 11/21/2022]
Abstract
The aim of this study was to compare the quality of dynamic wave arc (DWA) and coplanar volumetric modulated arc therapy (co-VMAT) plans for the treatment of localized prostate cancer. The planning target volume (PTV)-rectum, a section of the PTV comprising the PTV minus that of the rectum, received 78 Gy in 39 fractions as the mean dose to the PTV-rectum. The DWA and co-VMAT plans were generated for each patient using the RayStation treatment planning system for the Vero4DRT system. The PTV-rectum dose (D95%: the percent dose irradiating 95% of the volume), homogeneity index (HI), conformity index (CI), as well as doses to the bladder wall, rectum wall (V10-70 Gy: the percent volume receiving 10-70 Gy), and bilateral femoral heads of the DWA and co-VMAT plans were compared. The output monitor unit (MU) and delivery time obtained for each set of plans were also investigated. In terms of target coverage, the DWA plans provided an average D95% of 75.5 Gy, which was comparable to the co-VMAT-plan D95% of 75.2 Gy (p < 0.05). The HI was significantly better with the DWA. As for the DWA plans, the bladder-wall volume receiving 10, 20, 30, and 40 Gy (V10-40 Gy) was significantly smaller than that of the co-VMAT plans, and the volume of the rectal wall receiving 10 Gy (V10Gy) was significantly larger than that of the co-VMAT plans. The DWA plans yielded a reduced dose to the bilateral femoral heads compared with the co-VMAT plans (p < 0.05). The values of the CI and MU, and the delivery time exhibited no significant differences between the DWA and co-VMAT plans. The DWA plan is a feasible treatment option for prostate cancer radiotherapy.
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Rostamzadeh M, Ishihara Y, Nakamura M, Popescu IA, Mestrovic A, Gete E, Fedrigo R, Bergman AM. Monte Carlo simulation of 6-MV dynamic wave VMAT deliveries by Vero4DRT linear accelerator using EGSnrc moving sources. J Appl Clin Med Phys 2020; 21:206-218. [PMID: 33219743 PMCID: PMC7769401 DOI: 10.1002/acm2.13090] [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: 06/07/2020] [Revised: 08/12/2020] [Accepted: 10/06/2020] [Indexed: 12/02/2022] Open
Abstract
The commissioning and benchmark of a Monte Carlo (MC) model of the 6‐MV Brainlab‐Mitsubishi Vero4DRT linear accelerator for the purpose of quality assurance of clinical dynamic wave arc (DWA) treatment plans is reported. Open‐source MC applications based on EGSnrc particle transport codes are used to simulate the medical linear accelerator head components. Complex radiotherapy irradiations can be simulated in a single MC run using a shared library format combined with BEAMnrc “source20.” Electron energy tuning is achieved by comparing measured vs simulated percentage depth doses (PDDs) for MLC‐defined field sizes in a water phantom. Electron spot size tuning is achieved by comparing measured and simulated inplane and crossplane beam profiles. DWA treatment plans generated from RayStation (RaySearch) treatment planning system (TPS) are simulated on voxelized (2.5 mm3) patient CT datasets. Planning target volume (PTV) and organs at risk (OAR) dose–volume histograms (DVHs) are compared to TPS‐calculated doses for clinically deliverable dynamic volumetric modulated arc therapy (VMAT) trajectories. MC simulations with an electron beam energy of 5.9 MeV and spot size FWHM of 1.9 mm had the closest agreement with measurement. DWA beam deliveries simulated on patient CT datasets results in DVH agreement with TPS‐calculated doses. PTV coverage agreed within 0.1% and OAR max doses (to 0.035 cc volume) agreed within 1 Gy. This MC model can be used as an independent dose calculation from the TPS and as a quality assurance tool for complex, dynamic radiotherapy treatment deliveries. Full patient CT treatment simulations are performed in a single Monte Carlo run in 23 min. Simulations are run in parallel using the Condor High‐Throughput Computing software1 on a cluster of eight servers. Each server has two physical processors (Intel Xeon CPU E5‐2650 0 @2.00 GHz), with 8 cores per CPU and two threads per core for 256 calculation nodes.
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Affiliation(s)
- Maryam Rostamzadeh
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
| | | | | | | | - Ante Mestrovic
- Medical Physics Department, BC Cancer-Vancouver, Vancouver, Canada
| | - Ermias Gete
- Medical Physics Department, BC Cancer-Vancouver, Vancouver, Canada
| | - Roberto Fedrigo
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, Canada
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Iramina H, Nakamura M, Mizowaki T. Direct measurement and correction of both megavoltage and kilovoltage scattered x-rays for orthogonal kilovoltage imaging subsystems with dual flat panel detectors. J Appl Clin Med Phys 2020; 21:143-154. [PMID: 32710529 PMCID: PMC7497931 DOI: 10.1002/acm2.12986] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To measure the scattered x-rays of megavoltage (MV) and kilovoltage (kV) beams (MV scatter and kV scatter, respectively) on the orthogonal kV imaging subsystems of Vero4DRT. METHODS Images containing MV- and kV-scatter from another source only (i.e., MV- and kV-scatter maps) were acquired for each investigated flat panel detector. The reference scatterer was a water-equivalent cuboid phantom. The maps were acquired by changing one of the following parameters from the reference conditions while keeping the others fixed: field size: 10.0 × 10.0 cm2 ; dose rate: 400 MU/min; gantry and ring angles: 0°; kV collimator aperture size at isocenter: 10.0 × 10.0 cm2 : tube voltage: 110 kV; and exposure: 0.8 mAs. The average pixel values of MV- and kV-scatter (i.e., the MV- and kV-scatter values) at the center of each map were calculated and normalized to the MV-scatter value under the reference conditions (MV- and kV-scatter value factor, respectively). In addition, an MV- and kV-scatter correction experiment with intensity-modulated beams was performed using a phantom with four gold markers (GMs). The ratios between the intensities of the GMs and those of their surroundings were calculated. RESULTS The measurements showed a strong dependency of the MV-scatter on the field size and dose rate. The maximum MV-scatter value factors were 2.0 at a field size of 15.0 × 15.0 cm2 and 2.5 at a dose rate of 500 MU/min. The maximum kV-scatter value was 0.48 with a fully open kV collimator aperture. In the phantom experiment, the intensity ratios of kV images with MV- and kV-scatter were decreased from the reference ones. After correction of kV-scatter only, MV-scatter only, and both MV- and kV-scatter, the intensity ratios gradually improved. CONCLUSIONS MV- and kV-scatter could be corrected by subtracting the scatter maps from the projections, and the correction improved the intensity ratios of the GMs.
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Affiliation(s)
- Hiraku Iramina
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Hospital, Kyoto, Japan
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Hospital, Kyoto, Japan.,Division of Medical Physics, Department of Information Technology and Medical Engineering, Faculty of Human Health Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Hospital, Kyoto, Japan.,Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Hiraoka M, Mizowaki T, Matsuo Y, Nakamura M, Verellen D. The gimbaled-head radiotherapy system: Rise and downfall of a dedicated system for dynamic tumor tracking with real-time monitoring and dynamic WaveArc. Radiother Oncol 2020; 153:311-318. [PMID: 32659250 DOI: 10.1016/j.radonc.2020.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 10/23/2022]
Abstract
A gimbaled-head radiotherapy device was developed by industry-academic collaborations, with a concept of robust structures whilst maintaining high flexibilities, and its clinical application started in 2008. The unique structures with multi-image guidance functions initiated 2 new treatment modalities. One is dynamic tumor tracking radiotherapy with real time monitoring (DTTRM), which enables 4-D radiotherapy without prolongation of radiotherapy treatment time. This treatment has become clinically feasible for stereotactic body radiotherapy (SBRT) of lung cancers and liver tumors, and intensity-modulated radiotherapy (IMRT) for pancreatic cancers. The second one is Dynamic WaveArc therapy (DWA), the non-coplanar versatility of the SBRT system by combining the gantry-ring synchronized rotation with dynamic multileaf collimator optimization. DWA opens the possibility to create patient-individualized treatment plans, allowing additional flexibility in organ at risk sparing while preserving dosimetric robust delivery. The clinical usefulness of the DWA has been preliminary shown for those tumors in the prostate, breast and skull base. Prospective clinical trials are under way with a support of the national funding of Japan for DTTRM and DWA, respectively. Marketing of the system was terminated in 2016 due to a commercial decision. However, lessons can be learned from the development process of this device that might be useful for those who have interests in new technologies and clinical applications in radiation oncology. This review article aims to summarize the developments and achievements of a gimbaled-head radiotherapy device with a focus on DTTRM and DWA.
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Affiliation(s)
- Masahiro Hiraoka
- Department of Radiation Oncology, Japanese Red Cross Wakayama Medical Center, Japan.
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Japan
| | - Mitsuhiro Nakamura
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, Japan
| | - Dirk Verellen
- Iridium Kankernetwerk, Antwerp University, Faculty of Medicine and Health Sciences, Belgium
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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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Nakamura A, Hiraoka M, Itasaka S, Nakamura M, Akimoto M, Ishihara Y, Mukumoto N, Goto Y, Kishi T, Yoshimura M, Matsuo Y, Yano S, Mizowaki T. Evaluation of Dynamic Tumor-tracking Intensity-modulated Radiotherapy for Locally Advanced Pancreatic Cancer. Sci Rep 2018; 8:17096. [PMID: 30459454 PMCID: PMC6244273 DOI: 10.1038/s41598-018-35402-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 11/05/2018] [Indexed: 12/25/2022] Open
Abstract
Intensity-modulated radiotherapy (IMRT) is now regarded as an important treatment option for patients with locally advanced pancreatic cancer (LAPC). To reduce the underlying tumor motions and dosimetric errors during IMRT as well as the burden of respiratory management for patients, we started to apply a new treatment platform of the dynamic tumor dynamic tumor-tracking intensity-modulated radiotherapy (DTT-IMRT) using the gimbaled linac, which can swing IMRT toward the real-time tumor position under patients' voluntary breathing. Between June 2013 and March 2015, ten patients were treated, and the tumor-tracking accuracy and the practical benefits were evaluated. The mean PTV size in DTT-IMRT was 18% smaller than a conventional ITV-based PTV. The root-mean-squared errors between the predicted and the detected tumor positions were 1.3, 1.2, and 1.5 mm in left-right, anterior-posterior, and cranio-caudal directions, respectively. The mean in-room time was 24.5 min. This high-accuracy of tumor-tracking with reasonable treatment time are promising and beneficial to patients with LAPC.
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Affiliation(s)
- Akira Nakamura
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masahiro Hiraoka
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
| | - Satoshi Itasaka
- Department of Radiation Oncology, Kurashiki Central Hospital, Kurashiki, Japan
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mami Akimoto
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoshitomo Ishihara
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nobutaka Mukumoto
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoko Goto
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takahiro Kishi
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Michio Yoshimura
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Shinsuke Yano
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-Applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Kumazaki Y, Ozawa S, Nakamura M, Kito S, Minemura T, Tachibana H, Nishio T, Ishikura S, Nishimura Y. An end-to-end postal audit test to examine the coincidence between the imaging isocenter and treatment beam isocenter of the IGRT linac system for Japan Clinical Oncology Group (JCOG) clinical trials. Phys Med 2018; 53:145-152. [PMID: 30241749 DOI: 10.1016/j.ejmp.2018.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/06/2018] [Accepted: 08/12/2018] [Indexed: 10/28/2022] Open
Abstract
PURPOSE The aim of this study was to develop an end-to-end postal audit test to examine the coincidence between the imaging isocenter and treatment beam isocenter of the image guided radiotherapy (IGRT) linac system for Japan Clinical Oncology Group (JCOG) trials, as a part of IGRT credentialing of institutions participating in JCOG trials. METHODS We developed an end-to-end postal audit test to verify radiation positional errors associated with IGRT techniques. This test is intended for simulating a clinical IGRT flow and uses a static cubic phantom measuring 15 × 15 × 15 cm3 and weighing approximately 3.4 kg. The phantom has four gold fiducial markers and a spherical dummy target for setup, with known shift values from the phantom center. Two pairs of Gafchromic RTQA2 films were inserted 5 mm from the phantom's anterior-posterior and right-left surfaces. Radiation positional errors at the isocenter were determined by analyzing the center of the radiation field on the films and the known shift values of the dummy target. The test was performed on 47 IGRT devices at 35 institutions. RESULTS Radiation positional errors were within acceptance levels (1 mm/1°) for 42 IGRT devices (89.4%) in the first check. Median time to complete IGRT credentialing was 11.5 days. This audit method was applicable for any radiotherapy machine with an IGRT device. CONCLUSIONS A postal audit test to verify radiation positional errors for JCOG trials was successfully developed. In the postal audit, all but one institution passed this credentialing item within two trials.
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Affiliation(s)
- Yu Kumazaki
- Department of Radiation Oncology, Saitama Medical University International Medical Center, 1397-1 Yamane, Hidaka, Saitama 350-1298, Japan.
| | - Shuichi Ozawa
- Department of Oncology, Institute of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Mitsuhiro Nakamura
- Division of Medical Physics, Department of Information Technology and Medical Engineering, Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Satoshi Kito
- Radiation Physics Section, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-Ku, Tokyo 113-8677, Japan
| | - Toshiyuki Minemura
- Center for Cancer Control and Information Services, National Cancer Center, 5-1-1 Tsukiji, Chuo-Ku, Tokyo 104-0045, Japan
| | - Hidenobu Tachibana
- Particle Therapy Division, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa City, Chiba 277-8577, Japan
| | - Teiji Nishio
- Department of Medical Physics, Tokyo Women's Medical University, 8-1 Kawatamachi, Shinjuku, Tokyo 162-8666, Japan
| | - Satoshi Ishikura
- Department of Radiology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan
| | - Yasumasa Nishimura
- Department of Radiation Oncology, Kindai University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan
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Nakayama S, Monzen H, Onishi Y, Kaneshige S, Kanno I. Estimation of extremely small field radiation dose for brain stereotactic radiotherapy using the Vero4DRT system. Phys Med 2018; 50:52-58. [DOI: 10.1016/j.ejmp.2018.05.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 10/14/2022] Open
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Yamashita M, Takahashi R, Kokubo M, Takayama K, Tanabe H, Sueoka M, Ishii M, Tachibana H. A feasibility study of independent verification of dose calculation for Vero4DRT using a Clarkson-based algorithm. Med Dosim 2018; 44:20-25. [PMID: 29395462 DOI: 10.1016/j.meddos.2017.12.007] [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: 06/08/2017] [Revised: 12/04/2017] [Accepted: 12/22/2017] [Indexed: 10/17/2022]
Abstract
Dose verification for a gimbal-mounted image-guided radiotherapy system, Vero4DRT (Mitsubishi Heavy Industries Ltd., Tokyo, Japan) is usually carried out by pretreatment measurement. Independent verification calculations using Monte Carlo methods for Vero4DRT have been published. As the Clarkson method is faster and easier to use than measurement and Monte Carlo methods, we evaluated the accuracy of an independent calculation verification program and its feasibility as a secondary check for Vero4DRT. Computed tomography (CT)-based dose calculation was performed using a modified Clarkson-based algorithm. In this study, 120 patients' treatment plans were collected in our institute. The treatments were performed using conventional irradiation for lung and prostate, 3-dimensional (3D) conformal stereotactic body radiotherapy (SBRT) for the lung, and intensity-modulated radiation therapy (IMRT) for the prostate. Differences between the treatment planning system (TPS) and the Clarkson-based independent dose verification software were computed, and confidence limits (CLs, mean ± 2 standard deviation %) for Vero4DRT were compared with the CLs for the C-arms linear accelerators in the previous study. The results of the CLs, the conventional irradiation, SBRT, and IMRT showed 2.2 ± 3.5% (CL of the C-arms linear accelerators: 2.4 ± 5.3%), 1.1 ± 1.7% (-0.3 ± 2.0%), 4.8 ± 3.7% (5.4 ± 5.3%), and -0.5 ± 2.5% (-0.1 ± 3.6%) differences, respectively. The dose disagreement between the TPS and CT-based independent dose verification software was less than the 5% action level of American Association of Physicists in Medicine (AAPM) Task Group 114 (TG114). The CLs for the gimbal-mounted Vero4DRT were similar to the deviations for C-arms linear accelerators.
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Affiliation(s)
- Mikiko Yamashita
- Department of Radiological Technology, Kobe City Medical Center General Hospital, Hyogo 650-0047, Japan; Radiation Oncology Group, Institute of Biomedical Research and Innovation Laboratory, Hyogo 650-0047, Japan
| | - Ryo Takahashi
- Department of Radiation Oncology, The Cancer Institute Hospital of the Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan
| | - Masaki Kokubo
- Department of Radiation Oncology, Kobe City Medical Center General Hospital, Hyogo 650-0047, Japan
| | - Kenji Takayama
- Department of Radiation Oncology and Image-Applied Medicine Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Hiroaki Tanabe
- Department of Radiological Technology, Kobe City Medical Center General Hospital, Hyogo 650-0047, Japan
| | - Masaki Sueoka
- Department of Radiological Technology, Kobe City Medical Center General Hospital, Hyogo 650-0047, Japan
| | - Masao Ishii
- Department of Radiological Technology, Kobe City Medical Center West Hospital, Hyogo 653-0013, Japan
| | - Hidenobu Tachibana
- Particle Therapy Division, Research Center for Innovative Oncology, National Cancer Center, Chiba 277-8577, Japan.
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Sasaki M, Nakamura M, Mukumoto N, Nakata M, Hiraoka M. Dosimetric impact of translational and rotational setup errors for spine stereotactic body radiotherapy: A phantom study. Med Dosim 2017; 43:320-326. [PMID: 29217331 DOI: 10.1016/j.meddos.2017.10.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 09/26/2017] [Accepted: 10/31/2017] [Indexed: 11/19/2022]
Abstract
This study aimed to investigate experimentally the effect of translational and rotational setup errors on 3-dimensional dose distributions by using the gamma index and dose volumetric indices for spine stereotactic body radiotherapy. Treatment plans were designed in accordance with the Radiation Therapy Oncology Group (RTOG) 0631 protocol. Measurements were taken using a Delta4 phantom (ScandiDos, Uppsala, Sweden). Setup errors were generated using the HexaMotion 6D moving platform (ScandiDos). Dose distributions in the presence of setup errors were evaluated, according to the γ passing rate with the 3% and 2 mm criteria (γ3%/2 mm) and dose volumetric indices (D90 for the target volume and D2 for the spinal cord), using the Delta4 device (ScandiDos). The sensitivity coefficient, which represented the correlation between the γ3%/2 mm passing rate and dose volumetric indices, was determined to assess robustness against setup errors. Rotational setup errors of 2° were equivalent to translational setup errors of 2 mm for the γ3%/2 mm passing rate, D90 for the target, and D2 for the spinal cord. D90 for the target had low robustness against a translational setup error in the vertical direction and a rotational setup error in the pitch direction. D2 for the spinal cord was sensitive to a translational setup error in the lateral direction and a rotational setup error in the roll direction. The positioning accuracy of the rotational setup error, corresponding to the tolerance level of image-guided radiotherapy in the RTOG 0631 protocol, was required to be ≤ 2°.
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Affiliation(s)
- Makoto Sasaki
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Nobutaka Mukumoto
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Manabu Nakata
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto, Japan
| | - Masahiro Hiraoka
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Tsuruta Y, Nakamura M, Miyabe Y, Nakata M, Ishihara Y, Mukumoto N, Akimoto M, Ono T, Yano S, Higashimura K, Matsuo Y, Mizowaki T, Hiraoka M. Use of a second-dose calculation algorithm to check dosimetric parameters for the dose distribution of a first-dose calculation algorithm for lung SBRT plans. Phys Med 2017; 44:86-95. [PMID: 28760507 DOI: 10.1016/j.ejmp.2017.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 07/06/2017] [Accepted: 07/22/2017] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To verify lung stereotactic body radiotherapy (SBRT) plans using a secondary treatment planning system (TPS) as an independent method of verification and to define tolerance levels (TLs) in lung SBRT between the primary and secondary TPSs. METHODS A total of 147 lung SBRT plans calculated using X-ray voxel Monte Carlo (XVMC) were exported from iPlan to Eclipse in DICOM format. Dose distributions were recalculated using the Acuros XB (AXB) and the anisotropic analytical algorithm (AAA), while maintaining monitor units (MUs) and the beam arrangement. Dose to isocenter and dose-volumetric parameters, such as D2, D50, D95 and D98, were evaluated for each patient. The TLs of all parameters between XVMC and AXB (TLAXB) and between XVMC and AAA (TLAAA) were calculated as the mean±1.96 standard deviations. RESULTS AXB values agreed with XVMC values within 3.5% for all dosimetric parameters in all patients. By contrast, AAA sometimes calculated a 10% higher dose in PTV D95 and D98 than XVMC. The TLAXB and TLAAA of the dose to isocenter were -0.3±1.4% and 0.6±2.9%, respectively. Those of D95 were 1.3±1.8% and 1.7±3.6%, respectively. CONCLUSIONS This study quantitatively demonstrated that the dosimetric performance of AXB is almost equal to that of XVMC, compared with that of AAA. Therefore, AXB is a more appropriate algorithm for an independent verification method for XVMC.
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Affiliation(s)
- Yusuke Tsuruta
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto 606-8507, Japan
| | - Mitsuhiro Nakamura
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
| | - Yuki Miyabe
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Manabu Nakata
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto 606-8507, Japan
| | - Yoshitomo Ishihara
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Nobutaka Mukumoto
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Mami Akimoto
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Tomohiro Ono
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Shinsuke Yano
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto 606-8507, Japan
| | - Kyoji Higashimura
- Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto 606-8507, Japan
| | - Yukinori Matsuo
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Masahiro Hiraoka
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
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Prasetio H, Yohannes I, Bert C. Effect of VERO pan-tilt motion on the dose distribution. J Appl Clin Med Phys 2017; 18:144-154. [PMID: 28585287 PMCID: PMC5874935 DOI: 10.1002/acm2.12112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/31/2017] [Accepted: 04/14/2017] [Indexed: 11/11/2022] Open
Abstract
Tumor tracking is an option for intra-fractional motion management in radiotherapy. The VERO gimbal tracking system creates a unique beam geometry and understanding the effect of the gimbal motion in terms of dose distribution is important to assess the dose deviation from the reference conditions. Beam profiles, output factors (OF) and percentage depth doses (PDD) were measured and evaluated to investigate this effect. In order to find regions affected by the pan-tilt motion, synthesized 2D dose distributions were generated. An evaluation of the 2D dose distribution with the reference position was done using dose difference criteria 1%-4%. The OF and point dose at central axis were measured and compared with the reference position. Furthermore, the PDDs were measured using a special monitoring approach to filtering inaccurate points during the acquisition. Beam profiles evaluation showed that the effect of pan-tilt at inline direction was stronger than at the crossline direction. The maximum average deviation of the full width half maximum (FWHM), flatness, symmetry, penumbra left and right were 0.39 ± 0.25 mm, 0.62 ± 0.50%, 0.76 ± 0.59%, 0.22 ± 0.16 mm, and 0.19 ± 0.15 mm respectively. The ÔF and the measured dose average deviation were <0.5%. The mechanical accuracies during the PDD measurements were 0.28 ± 0.09 mm and 0.21 ± 0.09 mm for pan and tilt and pan or tilt position. The PDD average deviations were 0.58 ± 0.26 % and 0.54 ± 0.25 % for pan-or-tilt and pan-and-tilt position respectively. All the results showed that the deviation at pan and tilt position are higher than pan or tilt. The most influences were observed for the penumbra region and the shift of radiation beam path.
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Affiliation(s)
- Heru Prasetio
- Department of Radiation OncologyUniversitätsklinikum ErlangenFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Indra Yohannes
- Department of Radiation OncologyUniversitätsklinikum ErlangenFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
| | - Christoph Bert
- Department of Radiation OncologyUniversitätsklinikum ErlangenFriedrich‐Alexander‐Universität Erlangen‐NürnbergErlangenGermany
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15
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Miura H, Ozawa S, Hayata M, Tsuda S, Yamada K, Nagata Y. Effect of tumor amplitude and frequency on 4D modeling of Vero4DRT system. Rep Pract Oncol Radiother 2017; 22:290-294. [PMID: 28507458 DOI: 10.1016/j.rpor.2017.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 10/07/2016] [Accepted: 02/27/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND An important issue in indirect dynamic tumor tracking with the Vero4DRT system is the accuracy of the model predictions of the internal target position based on surrogate infrared (IR) marker measurement. We investigated the predictive uncertainty of 4D modeling using an external IR marker, focusing on the effect of the target and surrogate amplitudes and periods. METHODS A programmable respiratory motion table was used to simulate breathing induced organ motion. Sinusoidal motion sequences were produced by a dynamic phantom with different amplitudes and periods. To investigate the 4D modeling error, the following amplitudes (peak-to-peak: 10-40 mm) and periods (2-8 s) were considered. The 95th percentile 4D modeling error (4D-E95%) between the detected and predicted target position (μ + 2SD) was calculated to investigate the 4D modeling error. RESULTS 4D-E95% was linearly related to the target motion amplitude with a coefficient of determination R2 = 0.99 and ranged from 0.21 to 0.88 mm. The 4D modeling error ranged from 1.49 to 0.14 mm and gradually decreased with increasing target motion period. CONCLUSIONS We analyzed the predictive error in 4D modeling and the error due to the amplitude and period of target. 4D modeling error substantially increased with increasing amplitude and decreasing period of the target motion.
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Affiliation(s)
- Hideharu Miura
- Hiroshima High-Precision Radiotherapy Cancer Center, Japan
| | - Shuichi Ozawa
- Hiroshima High-Precision Radiotherapy Cancer Center, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Science, Hiroshima University, Japan
| | | | - Shintaro Tsuda
- Hiroshima High-Precision Radiotherapy Cancer Center, Japan
| | - Kiyoshi Yamada
- Hiroshima High-Precision Radiotherapy Cancer Center, Japan
| | - Yasushi Nagata
- Hiroshima High-Precision Radiotherapy Cancer Center, Japan
- Department of Radiation Oncology, Institute of Biomedical & Health Science, Hiroshima University, Japan
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16
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Evaluation of cone-beam computed tomography image quality assurance for Vero4DRT system. Rep Pract Oncol Radiother 2017; 22:258-263. [PMID: 28479875 DOI: 10.1016/j.rpor.2016.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/09/2016] [Accepted: 12/02/2016] [Indexed: 01/20/2023] Open
Abstract
We report the characteristics of quality assurance (QA) image for Vero4DRT system with a kilo-voltage (kV) cone-beam computed tomography (CBCT) capability to perform image-guided radiation therapy (IGRT). To acquire a set of CBCT, the kV source is rotated either 215° clockwise (CW) (tube 1 from 5° to 220° and tube 2 from 275° to 130°) or counterclockwise (CCW) (tube 1 from 85° to 230° and tube 2 from 355° to 140°). Image geometry, image uniformity, high/low contrast resolutions, and contrast linearity were measured with a Catphan 504 CT phantom (The Phantom Laboratory, NY). The comparison between measured and expected distances shows an excellent agreement. The CBCT for Vero4DRT system cannot perform a full 360° rotation, which leads to a loss in uniformity for image acquisition. Separations were observed for high-contrast resolution, with eight line pairs per centimeter corresponding to a gap size of 0.063 cm. For low-contrast resolution, the seventh largest hole was visible. This hole has a 4-mm diameter with 1.0% contrast level. We should check the contrast linearity compared with known value, even though it is out of range from the manufacturer manual.
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17
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Ono T, Miyabe Y, Yokota K, Takahashi K, Akimoto M, Mukumoto N, Ishihara Y, Nakamura M, Mizowaki T, Hiraoka M. Development of a gimbal-swing irradiation technique for uniform expanded-field, wedged-beam, and intensity-modulated radiation therapy. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/6/065007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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18
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Garibaldi C, Piperno G, Ferrari A, Surgo A, Muto M, Ronchi S, Bazani A, Pansini F, Cremonesi M, Jereczek-Fossa BA, Orecchia R. Translational and rotational localization errors in cone-beam CT based image-guided lung stereotactic radiotherapy. Phys Med 2016; 32:859-65. [PMID: 27289354 DOI: 10.1016/j.ejmp.2016.05.055] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 05/16/2016] [Accepted: 05/18/2016] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Accurate localization is crucial in delivering safe and effective stereotactic body radiation therapy (SBRT). The aim of this study was to analyse the accuracy of image-guidance using the cone-beam computed tomography (CBCT) of the VERO system in 57 patients treated for lung SBRT and to calculate the treatment margins. MATERIALS AND METHODS The internal target volume (ITV) was obtained by contouring the tumor on maximum and mean intensity projection CT images reconstructed from a respiration correlated 4D-CT. Translational and rotational tumor localization errors were identified by comparing the manual registration of the ITV to the motion-blurred tumor on the CBCT and they were corrected by means of the robotic couch and the ring rotation. A verification CBCT was acquired after correction in order to evaluate residual errors. RESULTS The mean 3D vector at initial set-up was 6.6±2.3mm, which was significantly reduced to 1.6±0.8mm after 6D automatic correction. 94% of the rotational errors were within 3°. The PTV margins used to compensate for residual tumor localization errors were 3.1, 3.5 and 3.3mm in the LR, SI and AP directions, respectively. CONCLUSIONS On-line image guidance with the ITV-CBCT matching technique and automatic 6D correction of the VERO system allowed a very accurate tumor localization in lung SBRT.
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Affiliation(s)
- Cristina Garibaldi
- Unit of Radiation Research, European Institute of Oncology, Milano, Italy.
| | - Gaia Piperno
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Annamaria Ferrari
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Alessia Surgo
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Matteo Muto
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Sara Ronchi
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Alessia Bazani
- Unit of Medical Physics, European Institute of Oncology, Milano, Italy
| | - Floriana Pansini
- Unit of Medical Physics, European Institute of Oncology, Milano, Italy
| | - Marta Cremonesi
- Unit of Radiation Research, European Institute of Oncology, Milano, Italy
| | - Barbara Alicja Jereczek-Fossa
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy; Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Roberto Orecchia
- Department of Health Sciences, Università degli Studi di Milano, Milano, Italy; Scientific Director, European Institute of Oncology, Milano, Italy
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Sothmann T, Blanck O, Poels K, Werner R, Gauer T. Real time tracking in liver SBRT: comparison of CyberKnife and Vero by planning structure-based γ-evaluation and dose-area-histograms. Phys Med Biol 2016; 61:1677-91. [PMID: 26836488 DOI: 10.1088/0031-9155/61/4/1677] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The purpose of this study was to evaluate and compare two clinical tracking systems for radiosurgery with regard to their dosimetric and geometrical accuracy in liver SBRT: the robot-based CyberKnife and the gimbal-based Vero. Both systems perform real-time tumour tracking by correlating internal tumour and external surrogate motion. CyberKnife treatment plans were delivered to a high resolution 2D detector array mounted on a 4D motion platform, with the platform simulating (a) tumour motion trajectories extracted from the corresponding CyberKnife predictor log files and (b) the tumour motion trajectories with superimposed baseline-drift. Static reference and tracked dose measurements were compared and dosimetric as well as geometrical uncertainties analyzed by a planning structure-based evaluation. For (a), γ-passing rates inside the CTV (γ-criteria of 1% / 1 mm) ranged from 95% to 100% (CyberKnife) and 98% to 100% (Vero). However, dosimetric accuracy decreases in the presence of the baseline-drift. γ-passing rates for (b) ranged from 26% to 92% and 94% to 99%, respectively; i.e. the effect was more pronounced for CyberKnife. In contrast, the Vero system led to maximum dose deviations in the OAR between +1.5 Gy to +6.0 Gy (CyberKnife: +0.5 Gy to +3.5 Gy). Potential dose shifts were interpreted as motion-induced geometrical tracking errors. Maximum observed shift ranges were -1.0 mm to +0.7 mm (lateral) /-0.6 mm to +0.1 mm (superior-inferior) for CyberKnife and -0.8 mm to +0.2 mm /-0.8 mm to +0.4 mm for Vero. These values illustrate that CyberKnife and Vero provide high precision tracking of regular breathing patterns. Even for the modified motion trajectory, the obtained dose distributions appear to be clinical acceptable with regard to literature QA γ-criteria of 3% / 3 mm.
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Affiliation(s)
- T Sothmann
- Department of Radiotherapy and Radio-Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany. Department of Computational Neuroscience, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
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Akimoto M, Nakamura M, Miyabe Y, Mukumoto N, Yokota K, Mizowaki T, Hiraoka M. Long-term stability assessment of a 4D tumor tracking system integrated into a gimbaled linear accelerator. J Appl Clin Med Phys 2015; 16:373–380. [PMID: 26699328 PMCID: PMC5690148 DOI: 10.1120/jacmp.v16i5.5679] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 05/26/2015] [Accepted: 05/26/2015] [Indexed: 12/25/2022] Open
Abstract
We assessed long‐term stability of tracking accuracy using the Vero4DRT system. This metric was observed between September 2012 and March 2015. A programmable respiratory motion phantom, designed to move phantoms synchronously with respiratory surrogates, was used. The infrared (IR) markers moved in the anterior–posterior (AP) direction as respiratory surrogates, while a cube phantom with a steel ball at the center, representing the tumor, and with radiopaque markers around it moved in the superior–inferior (SI) direction with one‐dimensional (1D) sinusoidal patterns. A correlation model between the tumor and IR marker motion (4D model) was created from the training data obtained for 20 s just before beam delivery. The irradiation field was set to 3×3 cm2 and 300 monitor units (MUs) of desired MV X‐ray beam were delivered. The gantry and ring angles were set to 0° and 45°, respectively. During beam delivery, the system recorded approximately 60 electronic portal imaging device (EPID) images. We analyzed: 1) the predictive accuracy of the 4D model (EP), defined as the difference between the detected and predicted target positions during 4D model creation, and 2) the tracking accuracy (ET), defined as the difference between the center of the steel ball and the MV X‐ray field on the EPID image. The median values of mean plus two standard deviations (SDs) for EP were 0.06, 0.35, and 0.06 mm in the left–right (LR), SI, and AP directions, respectively. The mean values of maximum deviation for ET were 0.38, 0.49, and 0.53 mm and the coefficients of variance (CV) were 0.16, 0.10, and 0.05 in lateral, longitudinal, and 2D directions, respectively. Consequently, the IR Tracking accuracy was consistent over a period of two years. Our proposed method assessed the overall tracking accuracy readily using real‐time EPID images, and proved to be a useful QA tool for dynamic tumor tracking with the Vero4DRT system. PACS number: 87.59.‐e, 88.10.gc, 87.55.Qr
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A novel method for dose distribution registration using fiducial marks made by a megavoltage beam in film dosimetry for intensity-modulated radiation therapy quality assurance. Phys Med 2015; 31:414-9. [PMID: 25724351 DOI: 10.1016/j.ejmp.2015.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 01/28/2015] [Accepted: 02/02/2015] [Indexed: 11/24/2022] Open
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Garibaldi C, Russo S, Ciardo D, Comi S, Seregni M, Fassi A, Piperno G, Ferrari A, Pansini F, Bazani A, Ricotti R, Jereczek-Fossa BA, Baroni G, Orecchia R. Geometric and dosimetric accuracy and imaging dose of the real-time tumour tracking system of a gimbal mounted linac. Phys Med 2015; 31:501-9. [PMID: 25934523 DOI: 10.1016/j.ejmp.2015.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/26/2015] [Accepted: 04/01/2015] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To suggest a comprehensive testing scheme to evaluate the geometric and dosimetric accuracy and the imaging dose of the VERO dynamic tumour tracking (DTT) for its clinical implementation. METHODS Geometric accuracy was evaluated for gantry 0° and 90° in terms of prediction (EP), mechanical (EM) and tracking (ET) errors for sinusoidal patterns with 10 and 20 mm amplitudes, 2-6 s periods and phase shift up to 1 s and for 3 patient patterns. The automatic 4D model update was investigated simulating changes in the breathing pattern during treatment. Dosimetric accuracy was evaluated with gafchromic films irradiated in static and moving phantom with and without DTT. The entrance skin dose (ESD) was assessed using a solid state detector and gafchromic films. RESULTS The RMS of EP, EM, and ET were up to 0.8, 0.5 and 0.9 mm for all non phased-shifted motion patterns while for the phased-shifted ones, EP and ET increased to 2.2 and 2.6 mm. Up to 4 updates are necessary to restore a good correlation model, according to type of change. For 100 kVp and 1 mA s X-ray beam, the ESD per portal due to 20 s fluoroscopy was 16.6 mGy, while treatment verification at a frequency of 1 Hz contributed with 4.2 mGy/min. CONCLUSIONS The proposed testing scheme highlighted that the VERO DTT system tracks a moving target with high accuracy. The automatic update of the 4D model is a powerful tool to guarantee the accuracy of tracking without increasing the imaging dose.
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Affiliation(s)
| | - Stefania Russo
- Unit of Medical Physics, European Institute of Oncology, Milano, Italy
| | - Delia Ciardo
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Stefania Comi
- Unit of Medical Physics, European Institute of Oncology, Milano, Italy
| | - Matteo Seregni
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Aurora Fassi
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Gaia Piperno
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Annamaria Ferrari
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Floriana Pansini
- Unit of Medical Physics, European Institute of Oncology, Milano, Italy
| | - Alessia Bazani
- Unit of Medical Physics, European Institute of Oncology, Milano, Italy
| | - Rosalinda Ricotti
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy
| | - Barbara Alicja Jereczek-Fossa
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy; Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
| | - Guido Baroni
- Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy
| | - Roberto Orecchia
- Department of Radiation Oncology, European Institute of Oncology, Milano, Italy; Department of Health Sciences, Università degli Studi di Milano, Milano, Italy
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Ishihara Y, Sawada A, Nakamura M, Miyabe Y, Tanabe H, Kaneko S, Takayama K, Mizowaki T, Kokubo M, Hiraoka M. Development of a dose verification system for Vero4DRT using Monte Carlo method. J Appl Clin Med Phys 2014; 15:4961. [PMID: 25493521 PMCID: PMC5711115 DOI: 10.1120/jacmp.v15i6.4961] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 07/08/2014] [Accepted: 07/01/2014] [Indexed: 11/23/2022] Open
Abstract
Vero4DRT is an innovative image-guided radiotherapy system employing a C-band X-ray head with gimbal mechanics. The purposes of this study were to propose specific MC models of the linac head and multileaf collimator (MLC) for the Vero4DRT and to verify their accuracy. For a 6 MV photon beam delivered by the Vero4DRT, a simulation code was implemented using EGSnrc. The linac head model and the MLC model were simulated based on its specification. Next, the percent depth dose (PDD) and beam profiles at depths of 15, 100, and 200 mm were simulated under source-to-surface distance of 900 and 1000 mm. Field size was set to 150 × 150 mm2 at a depth of 100 mm. Each of the simulated dosimetric metrics was then compared with the corresponding measurements by a 0.125 cc ionization chamber. After that, intra- and interleaf leakage, tongue-and-groove, and rounded-leaf profiles were simulated for the static MLC model. Meanwhile, film measurements were performed using EDR2 films under similar conditions to simulation. The measurement for the rounded-leaf profile was performed using the water phantom and the ionization chamber. The leaf physical density and abutting leaf gap were adjusted to obtain good agreement between the simulated intra- and interleaf leakage profiles and measurements. For the MLC model in step-and-shoot cases, a pyramid and a prostate IMRT field were simulated, while film measurements were performed using EDR2. For the linac head, exclusive of MLC, the difference in PDD was < 1.0% after the buildup region. The simulated beam profiles agreed to within 1.3% at each depth. The MLC model has been shown to reproduce dose measurements within 2.5% for static tests. The MLC is made of tungsten alloy with a purity of 95%. The leaf gap of 0.015 cm and the MLC physical density of 18.0 g/ cm3, which provided the best agreement between the simulated and measured leaf leakage, were assigned to our MC model. As a result, the simulated step-and-shoot IMRT dose distributions agreed with the film measurements to within 3.3%, with exception of the penumbra region. We have developed specific MC models of the linac head and the MLC in the Vero4DRT system. The results have demonstrated that our MC models have high accuracy.
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Affiliation(s)
- Yoshitomo Ishihara
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University.
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24
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Ono T, Miyabe Y, Yamada M, Yokota K, Kaneko S, Sawada A, Monzen H, Mizowaki T, Kokubo M, Hiraoka M. Development of an expanded-field irradiation technique using a gimbaled x-ray head. Med Phys 2014; 41:101706. [PMID: 25281945 DOI: 10.1118/1.4895016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The Vero4DRT has a maximum field size of 150.0 × 150.0 mm. The purpose of the present study was to develop expanded-field irradiation techniques using the unique gimbaled x-ray head of the Vero4DRT and to evaluate the dosimetric characteristics thereof. METHODS Two techniques were developed. One features gimbal swing irradiation and multiple static segments consisting of four separate fields exhibiting 2.39° gimbal rotation around two orthogonal axes. The central beam axis for each piecewise-field is shifted 40 mm from the isocenters of the left-right (LR) and superior-inferior (SI) directions, and, thus, the irradiation field size is expanded to 230.8 × 230.8 mm. Adjacent regions were created at the isocenter (a center-adjacent expandedfield) and 20 mm from the isocenter (an off-adjacent expandedfield). The field gaps or overlaps of combined piecewise-fields were established by adjustment of gimbal rotation and movement of the multileaf collimator (MLC). Another technique features dynamic segment irradiation in which the beam is delivered while rotating the gimbal. The dose profile is controlled by a combination of gimbal swing motion and opening and closing of the MLC. This enabled the authors to expand the irradiation field on the LR axis because the direction of MLC motion is parallel to that axis. A field 220.6 × 150.0 mm in dimensions was configured and examined. To evaluate the dosimetric characteristics of the expandedfields, films inserted into water-equivalent phantoms at depths of 50, 100, and 150 mm were irradiated and field sizes, penumbrae, flatness, and symmetry analyzed. In addition, the expanded-field irradiation techniques were applied to intensity-modulated radiation therapy (IMRT). A head-and-neck IMRT field, created using a conventional Linac (the Varian Clinac iX), was reproduced employing an expanded-field of the Vero4DRT. The simulated dose distribution for the expanded-IMRT field was compared to the measured dose distribution. RESULTS The field sizes, penumbrae, flatness, and symmetry of the center- and off-adjacent expanded-fields were 230.2-232.1 mm, 6.8-10.7 mm, 2.3%-5.1%, and -0.5% to -0.4%, respectively, at a depth of 100 mm. Similarly, the field sizes, penumbrae, flatness, and symmetry of dynamic segment irradiation on the LR axis were 219.2 mm, 6.0-6.2 mm, 3.4%, and -0.1%, respectively, at a depth of 100 mm. In the area of expanded-IMRT dose distribution, the passing rate of 5% dose difference was 85.8% between measurements and simulation, and the 3%/3 mm gamma passing rate was 96.4%. CONCLUSIONS Expanded-field irradiation techniques were developed using a gimbaled x-ray head. The techniques effectively extend target areas, as required when whole-breast irradiation or head-and-neck IMRT is contemplated.
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Affiliation(s)
- Tomohiro Ono
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Yuki Miyabe
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Masahiro Yamada
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Kenji Yokota
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Shuji Kaneko
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Akira Sawada
- Department of Radiological Technology, Faculty of Medical Science, Kyoto College of Medical Science, Nantan, Kyoto 622-0041, Japan
| | - Hajime Monzen
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Takashi Mizowaki
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Masaki Kokubo
- Division of Radiation Oncology, Institute of Biomedical Research and Innovation, Kobe 650-0047, Japan and Department of Radiation Oncology, Kobe City Medical Center General Hospital, Kobe 650-0047, Japan
| | - Masahiro Hiraoka
- Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
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25
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Matsuo Y, Ueki N, Takayama K, Nakamura M, Miyabe Y, Ishihara Y, Mukumoto N, Yano S, Tanabe H, Kaneko S, Mizowaki T, Monzen H, Sawada A, Kokubo M, Hiraoka M. Evaluation of dynamic tumour tracking radiotherapy with real-time monitoring for lung tumours using a gimbal mounted linac. Radiother Oncol 2014; 112:360-4. [DOI: 10.1016/j.radonc.2014.08.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 07/14/2014] [Accepted: 08/02/2014] [Indexed: 12/17/2022]
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26
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Appareillage et technologies de repositionnement en radiothérapie stéréotaxique extracrânienne. Cancer Radiother 2014; 18:253-7. [DOI: 10.1016/j.canrad.2014.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/19/2014] [Indexed: 12/31/2022]
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27
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Ogura K, Mizowaki T, Ishida Y, Hiraoka M. Dosimetric advantages of O-ring design radiotherapy system for skull-base tumors. J Appl Clin Med Phys 2014; 15:4608. [PMID: 24710448 PMCID: PMC5875486 DOI: 10.1120/jacmp.v15i2.4608] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 12/03/2013] [Accepted: 12/02/2013] [Indexed: 12/25/2022] Open
Abstract
The purpose of this study was to investigate whether a new O‐ring design radiotherapy delivery system has advantages in radiotherapy planning for skull‐base tumors. Twenty‐five patients with skull‐base tumors were included in this study. Two plans were made using conventional (Plan A) or new (Plan B) techniques. Plan A consisted of four dynamic conformal arcs (DCAs): two were horizontal, and the other two were from cranial directions. Plan B was created by converting horizontal arcs to those from caudal directions making use of the O‐ring design radiotherapy system. The micromultileaf collimators were fitted to cover at least 99% of the planning target volume with prescribed doses, 90% of the dose at the isocenter. The two plans were compared in terms of target homogeneity, conformity, and irradiated volume of normal tissues, using a two‐sided paired t‐test. For evaluation regarding target coverage, the homogeneity indices defined by the International Commission on Radiation Units and Measurements 83 were 0.099±0.010 (mean ± standard deviation) and 0.092±0.010, the conformity indices defined by the Radiation Therapy Oncology Group were 1.720±0.249 and 1.675±0.239, and the Paddick's conformity indices were 0.585±0.078 and 0.602±0.080, in Plans A and B, respectively. For evaluation of irradiated normal tissue, the Paddick's gradient indices were 3.118±0.283 and 2.938±0.263 in Plans A and B, respectively. All of these differences were statistically significant (p‐values <0.05). The mean doses of optic nerves, eyes, brainstem, and hippocampi were also significantly lower in Plan B. The DCA technique from caudal directions using the new O‐ring design radiotherapy system can improve target homogeneity and conformity compared with conventional DCA techniques, and can also decrease the volume of surrounding normal tissues that receives moderate doses. PACS numbers: 87.55.‐x, 87.55.D‐, 87.55.dk
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Affiliation(s)
- Kengo Ogura
- Graduate School of Medicine Kyoto University.
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28
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Solberg TD, Medin PM, Ramirez E, Ding C, Foster RD, Yordy J. Commissioning and initial stereotactic ablative radiotherapy experience with Vero. J Appl Clin Med Phys 2014; 15:4685. [PMID: 24710458 PMCID: PMC5875460 DOI: 10.1120/jacmp.v15i2.4685] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 12/29/2013] [Accepted: 11/01/2013] [Indexed: 12/31/2022] Open
Abstract
The purpose of this study is to describe the comprehensive commissioning process and initial clinical performance of the Vero linear accelerator, a new radiotherapy device recently installed at UT Southwestern Medical Center specifically developed for delivery of image‐guided stereotactic ablative radiotherapy (SABR). The Vero system utilizes a ring gantry to integrate a beam delivery platform with image guidance systems. The ring is capable of rotating ± 60° about the vertical axis to facilitate noncoplanar beam arrangements ideal for SABR delivery. The beam delivery platform consists of a 6 MV C‐band linac with a 60 leaf MLC projecting a maximum field size of 15×15 cm2 at isocenter. The Vero planning and delivery systems support a range of treatment techniques, including fixed beam conformal, dynamic conformal arcs, fixed gantry IMRT in either SMLC (step‐and‐shoot) or DMLC (dynamic) delivery, and hybrid arcs, which combines dynamic conformal arcs and fixed beam IMRT delivery. The accelerator and treatment head are mounted on a gimbal mechanism that allows the linac and MLC to pivot in two dimensions for tumor tracking. Two orthogonal kV imaging subsystems built into the ring facilitate both stereoscopic and volumetric (CBCT) image guidance. The system is also equipped with an always‐active electronic portal imaging device (EPID). We present our commissioning process and initial clinical experience focusing on SABR applications with the Vero, including: (1) beam data acquisition; (2) dosimetric commissioning of the treatment planning system, including evaluation of a Monte Carlo algorithm in a specially‐designed anthropomorphic thorax phantom; (3) validation using the Radiological Physics Center thorax, head and neck (IMRT), and spine credentialing phantoms; (4) end‐to‐end evaluation of IGRT localization accuracy; (5) ongoing system performance, including isocenter stability; and (6) clinical SABR applications. PACS number: 87.53.Ly
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Affiliation(s)
- Timothy D Solberg
- University of Pennsylvania, University of Texas Southwestern Medical Center.
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29
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Burghelea M, Verellen D, Gevaert T, Depuydt T, Poels K, Simon V, De Ridder M. Feasibility of using the Vero SBRT system for intracranial SRS. J Appl Clin Med Phys 2014; 15:4437. [PMID: 24423838 PMCID: PMC5711224 DOI: 10.1120/jacmp.v15i1.4437] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Revised: 09/25/2013] [Accepted: 08/30/2013] [Indexed: 11/23/2022] Open
Abstract
The Vero SBRT system was benchmarked in a planning study against the Novalis SRS system for quality of delivered dose distributions to intracranial lesions and assessing the Vero system's capacity for SRS. A total of 27 patients with one brain lesion treated on the Novalis system, with 3 mm leaf width MLC and C‐arm gantry, were replanned for Vero, with a 5 mm leaf width MLC mounted on an O‐ring gantry allowing rotations around both the horizontal and vertical axis. The Novalis dynamic conformal arc (DCA) planning included vertex arcs, using 90° couch rotation. These vertex arcs cannot be reproduced with Vero due to the mechanical limitations of the O‐ring gantry. Alternative class solutions were investigated for the Vero. Additionally, to distinguish between the effect of MLC leaf width and different beam arrangements on dose distributions, the Vero class solutions were also applied for Novalis. In addition, the added value of noncoplanar IMRT was investigated in this study. Quality of the achieved dose distributions was expressed in the conformity index (CI) and gradient index (GI), and compared using a paired Student's t‐test with statistical significance for p‐values ≤0.05. For lesions larger than 5 cm3, no statistical significant difference in conformity was observed between Vero and Novalis, but for smaller lesions, the dose distributions showed a significantly better conformity for the Novalis (ΔCI=13.74%, p=0.0002) mainly due to the smaller MLC leaf width. Using IMRT on Vero reduces this conformity difference to nonsignificant levels. The cutoff for achieving a GI around 3, characterizing a sharp dose falloff outside the target volume was 4 cm3 for Novalis and 7 cm3 for Vero using DCA technique. Using noncoplanar IMRT, this threshold was reduced to 3 cm3 for the Vero system. The smaller MLC and the presence of the vertex fields allow the Novalis system to better conform the dose around the lesion and to obtain steeper dose falloff outside the lesion. Comparable dosimetric characteristics can be achieved with Vero for lesions larger than 3 cm3 and using IMRT. PACS number: 87.55.D
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Nakamura M, Sawada A, Mukumoto N, Takahashi K, Mizowaki T, Kokubo M, Hiraoka M. Effect of audio instruction on tracking errors using a four-dimensional image-guided radiotherapy system. J Appl Clin Med Phys 2013; 14:255-64. [PMID: 24036880 PMCID: PMC5714564 DOI: 10.1120/jacmp.v14i5.4488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 06/10/2013] [Accepted: 06/10/2013] [Indexed: 12/25/2022] Open
Abstract
The Vero4DRT (MHI‐TM2000) is capable of performing X‐ray image‐based tracking (X‐ray Tracking) that directly tracks the target or fiducial markers under continuous kV X‐ray imaging. Previously, we have shown that irregular respiratory patterns increased X‐ray Tracking errors. Thus, we assumed that audio instruction, which generally improves the periodicity of respiration, should reduce tracking errors. The purpose of this study was to assess the effect of audio instruction on X‐ray Tracking errors. Anterior‐posterior abdominal skin‐surface displacements obtained from ten lung cancer patients under free breathing and simple audio instruction were used as an alternative to tumor motion in the superior‐inferior direction. First, a sequential predictive model based on the Levinson‐Durbin algorithm was created to estimate the future three‐dimensional (3D) target position under continuous kV X‐ray imaging while moving a steel ball target of 9.5 mm in diameter. After creating the predictive model, the future 3D target position was sequentially calculated from the current and past 3D target positions based on the predictive model every 70 ms under continuous kV X‐ray imaging. Simultaneously, the system controller of the Vero4DRT calculated the corresponding pan and tilt rotational angles of the gimbaled X‐ray head, which then adjusted its orientation to the target. The calculated and current rotational angles of the gimbaled X‐ray head were recorded every 5 ms. The target position measured by the laser displacement gauge was synchronously recorded every 10 msec. Total tracking system errors (ET) were compared between free breathing and audio instruction. Audio instruction significantly improved breathing regularity (p < 0.01). The mean ± standard deviation of the 95th percentile of ET (E95T) was 1.7 ± 0.5 mm (range: 1.1–2.6 mm) under free breathing (E95T,FB) and 1.9 ± 0.5 mm (range: 1.2–2.7 mm) under audio instruction (E95T,AI). E95T,AI was larger than E95T,FB for five patients; no significant difference was found between E95T,FB and ET,AI95(p = 0.21). Correlation analysis revealed that the rapid respiratory velocity significantly increased E95T. Although audio instruction improved breathing regularity, it also increased the respiratory velocity, which did not necessarily reduce tracking errors. PACS number: 87.55.ne, 87.57.N‐, 87.59.C‐,
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31
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Nakaguchi Y, Oono T, Araki F, Maruyama M. [Physical characterizations for an integrated 160-leaf multi-leaf collimator with a new concept design]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2013; 69:778-783. [PMID: 23877156 DOI: 10.6009/jjrt.2013_jsrt_69.7.778] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
In this article, we present a physical characterization of the agility(™) (Elekta). agility(™) is composed of 160 interdigitating multileaf collimators (MLCs) with a width of 5 mm at the isocenter. The physical characterizations that include leaf position accuracy, leakage, field penumbra and the tongue-and-groove (T&G) effect were evaluated using well-commissioned 4, 6 and 10-MV photon beams. The leaf position accuracy was within 0.5 mm for all gantry angles and each MLC. The leakage was 0.44% on average and reached 0.47% at 10 MV: remarkably low due to a new design with tilted leaves. However, the T&G effect occurred due to tilt. It was approximately 20.8% on average and reached 22.3% at 6 MV. The penumbra width increased up to 8.5 mm at a field size of 20×20 cm at 4 MV. High position designed MLCs create a wider penumbra but show lower leakage and large head clearance. Head clearance is an important factor in stereotactic radiotherapy with multiple non-coplanar beams.
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Affiliation(s)
- Yuji Nakaguchi
- Department of Radiological Technology, Kumamoto University Hospital
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32
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Yoganathan SA, Maria Das KJ, Agarwal A, Kumar S. Performance evaluation of respiratory motion-synchronized dynamic IMRT delivery. J Appl Clin Med Phys 2013; 14:4103. [PMID: 23652244 PMCID: PMC5714411 DOI: 10.1120/jacmp.v14i3.4103] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 01/15/2013] [Accepted: 12/09/2012] [Indexed: 12/25/2022] Open
Abstract
The purpose of this study was to evaluate the capabilities of DMLC to deliver the respiratory motion‐synchronized dynamic IMRT (MS‐IMRT) treatments under various dose rates. In order to create MS‐IMRT plans, the DMLC leaf motions in dynamic IMRT plans of eight lung patients were synchronized with the respiratory motion of breathing period 4 sec and amplitude 2 cm (peak to peak) using an in‐house developed leaf position modification program. The MS‐IMRT plans were generated for the dose rates of 100 MU/min, 400 MU/min, and 600 MU/min. All the MS‐IMRT plans were delivered in a medical linear accelerator, and the fluences were measured using a 2D ion chamber array, placed over a moving platform. The accuracy of MS‐IMRT deliveries was evaluated with respect to static deliveries (no compensation for target motion) using gamma test. In addition, the fluences of gated delivery of 30% duty cycle and non‐MS‐IMRT deliveries were also measured and compared with static deliveries. The MS‐IMRT was better in terms of dosimetric accuracy, compared to gated and non‐MS‐IMRT deliveries. The dosimetric accuracy was observed to be significantly better for 100 MU/min MS‐IMRT. However, the use of high‐dose rate in a MS‐IMRT delivery introduced dose‐rate modulation/beam hold‐offs that affected the synchronization between the DMLC leaf motion and target motion. This resulted in more dose deviations in MS‐IMRT deliveries at the dose rate of 600 MU/min. PACS numbers: 87.53.kn, 87.56.N‐
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Affiliation(s)
- S A Yoganathan
- Gautam Buddh Technical University, Lucknow, Uttar Pradesh, India.
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33
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Mukumoto N, Nakamura M, Sawada A, Suzuki Y, Takahashi K, Miyabe Y, Kaneko S, Mizowaki T, Kokubo M, Hiraoka M. Accuracy verification of infrared marker-based dynamic tumor-tracking irradiation using the gimbaled x-ray head of the Vero4DRT (MHI-TM2000)a). Med Phys 2013; 40:041706. [DOI: 10.1118/1.4794506] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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Davies GA, Clowes P, McQuaid D, Evans PM, Webb S, Poludniowski G. An experimental comparison of conventional two-bank and novel four-bank dynamic MLC tracking. Phys Med Biol 2013; 58:1635-48. [DOI: 10.1088/0031-9155/58/5/1635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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35
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Mukumoto N, Nakamura M, Sawada A, Takahashi K, Miyabe Y, Takayama K, Mizowaki T, Kokubo M, Hiraoka M. Positional accuracy of novel x-ray-image-based dynamic tumor-tracking irradiation using a gimbaled MV x-ray head of a Vero4DRT (MHI-TM2000). Med Phys 2012; 39:6287-96. [PMID: 23039664 DOI: 10.1118/1.4754592] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To verify the positional accuracy of a novel x-ray-image-based dynamic tumor-tracking (DTT) irradiation technique using the gimbaled MV x-ray head of a Vero4DRT (MHI-TM2000). METHODS Verification of the x-ray-image-based DTT was performed using three components: a three-dimensional moving phantom with a steel ball target, a laser displacement gauge, and an orthogonal kV x-ray imaging subsystem with a gimbaled MV x-ray head and the system controller of the Vero4DRT. The moving phantom was driven based on seven periodic patterns [peak-to-peak amplitude (A): 20-40 mm, breathing period (T): 2-5 s] and 15 patients' aperiodic respiratory patterns (A: 6.5-22.9 mm, T: 1.9-5.8 s). The target position was detected in real time with the orthogonal kV x-ray imaging subsystem using the stereo vision technique. Subsequently, the Vero4DRT predicted the next position of the target, and then the gimbaled MV x-ray head tracked the corresponding orientation of the target. The displacements of the target were measured synchronously using the laser displacement gauge. The difference between the target positions predicted by the Vero4DRT and those measured by the laser displacement gauge was computed as the prediction error (E(P)), and the difference between the target positions tracked by the gimbaled MV x-ray head and predicted target positions was computed as the mechanical error (E(M)). Total tracking system error (E(T)) was defined as the difference between the tracked and measured target positions. RESULTS The root mean squares (RMSs) of E(P), E(M), and E(T) were up to 0.8, 0.3, and 0.7 mm, respectively, for the periodic patterns. Regarding the aperiodic patterns, the median RMSs of E(P), E(M), and E(T) were 1.2 (range, 0.9-1.8) mm, 0.1 (range, 0.1-0.5) mm, and 1.2 (range, 0.9-1.8) mm, respectively. From the results of principal component analysis, tracking efficiency, defined as the ratio of twice the RMS of E(T) to A, was improved for patients with high respiratory function (R = 0.91; p < 0.01). CONCLUSIONS The present study demonstrated that the Vero4DRT is capable of high-accuracy x-ray-image-based DTT. E(T) was caused primarily by E(P), and E(M) was negligible. Furthermore, principal component analysis showed that tracking efficiency could be improved with this system, especially for patients with high respiratory function.
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Affiliation(s)
- Nobutaka Mukumoto
- Department of Radiation Oncology and Image-applied Therapy, Kyoto University, Kyoto, Japan
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36
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Akimoto M, Nakamura M, Mukumoto N, Yamada M, Ueki N, Matsuo Y, Sawada A, Mizowaki T, Kokubo M, Hiraoka M. Optimization of the x-ray monitoring angle for creating a correlation model between internal and external respiratory signals. Med Phys 2012; 39:6309-15. [DOI: 10.1118/1.4754648] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Galal MM, Keogh S, Khalil S. Dosimetric and mechanical characteristics of a commercial dynamic microMLC used in SRS. Med Phys 2011; 38:4225-31. [PMID: 21859024 DOI: 10.1118/1.3601018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The aim of this work is to carry out mechanical and dosimetric assessments on a commercial dynamic micromulti leaf collimator system to be used for stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT). Mechanical parameters such as leaf position accuracy with different gantry angles and leaf position reproducibility were measured. Also dosimetric measurements of the interleaf leakage, intraleaf transmission, penumbra width, and light field alignment were carried out. Furthermore, measurements of output factors (Sep) and in-air factors (Se) for the microMLC system will be reported. METHODS EBT2 films were used to assess the leaf position error with gantry angle and after stress test, penumbra width and light field alignment. Leaf leakage was quantified using both EBT2 film and a pinpoint ion chamber. With regard to output factors, the pinpoint chamber was placed in a water phantom at 10 cm depth and 100 cm SSD. For in-air output factor measurements, 0.2 cm of brass was placed above the photon diode as build-up. RESULTS Measurements of mechanical parameters gave values of 0.05 cm (SD 0.035) for the average leaf position accuracy for different gantry angles and after stress test. Dosimetric measurements, yielded values of 0.22 +/- 0.01 and 0.24 +/- 0.01 cm, respectively, for side and head leaf penumbras. Also, average leaf abutting, leakage and transmission were found to be 0.65, 0.91, and 0.20%, respectively. CONCLUSIONS (a) The add-on microMLC system in combination with our LINAC has been commissioned to be used for clinical purposes and showed good agreement with published results for different ,MLC types. (b) This work has lead to the recommendation that leaves should be recalibrated after ten static beams or after each dynamic arc.
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Affiliation(s)
- Mohamed M Galal
- Physics Department, Hermitage Medical Clinic, Dublin 20, Ireland
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Depuydt T, Verellen D, Haas O, Gevaert T, Linthout N, Duchateau M, Tournel K, Reynders T, Leysen K, Hoogeman M, Storme G, Ridder MD. Geometric accuracy of a novel gimbals based radiation therapy tumor tracking system. Radiother Oncol 2011; 98:365-72. [DOI: 10.1016/j.radonc.2011.01.015] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 01/14/2011] [Accepted: 01/16/2011] [Indexed: 12/21/2022]
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