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https://www.readbyqxmd.com/read/28343538/accelerated-hypofractionated-adjuvant-whole-breast-radiation-with-simultaneous-integrated-boost-using-volumetric-modulated-arc-therapy-for-early-breast-cancer-a-phase-i-ii-dosimetric-and-clinical-feasibility-study-from-a-tertiary-cancer-care-centre-of-india
#1
Dodul Mondal, Pramod Kumar Julka, Daya Nand Sharma, Manisha Jana, Macharla Anjaneyelu Laviraj, Suryanarayan Vs Deo, Soumyajit Roy, Randeep Guleria, Goura K Rath
BACKGROUND: Hypofractionation has become standard of care after Breast Conserving Therapy (BCT) in many European and few others western countries. Though still debatable, tumor cavity boost is routinely practised in our centre. Hypofractionation is not yet the current standard of practice in Asian countries. Employing hypofractionation and simultaneous integrated boost to lumpectomy cavity with conformal technique is not the current practice in this region. Hence the study was performed to see whether accelerated hypofractionation and simultaneous boost can be combined using volumetric modulated arc therapy (VMAT) in treating early breast cancer (EBC) patients...
March 2017: Journal of the Egyptian National Cancer Institute
https://www.readbyqxmd.com/read/28341061/vmat-plus-a-few-computer-optimized-non-coplanar-imrt-beams-vmat-tested-for-liver-sbrt
#2
Abdul Wahab M Sharfo, Maarten L P Dirkx, Sebastiaan Breedveld, Alejandra Méndez Romero, Ben J M Heijmen
PURPOSE: To propose a novel treatment approach, designated VMAT+, involving addition of <5 IMRT beams with computer-optimized non-coplanar orientations to VMAT, and evaluate it for liver Stereotactic Body Radiation Therapy (SBRT). VMAT+ is investigated as an alternative for (1) coplanar VMAT and (2) multi-beam non-coplanar treatment. METHODS/MATERIALS: For fifteen patients with liver metastases, VMAT+ plans were compared with (1) dual-arc VMAT and (2) 25-beam, non-coplanar treatment with computer-optimized beam orientations (25-NCP)...
March 22, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28339918/can-clinically-relevant-dose-errors-in-patient-anatomy-be-detected-by-gamma-passing-rate-or-modulation-complexity-score-in-volumetric-modulated-arc-therapy-for-intracranial-tumors
#3
Shingo Ohira, Yoshihiro Ueda, Masaru Isono, Akira Masaoka, Misaki Hashimoto, Masayoshi Miyazaki, Masaaki Takashina, Masahiko Koizumi, Teruki Teshima
We investigated whether methods conventionally used to evaluate patient-specific QA in volumetric-modulated arc therapy (VMAT) for intracranial tumors detect clinically relevant dosimetric errors. VMAT plans with coplanar arcs were designed for 37 intracranial tumors. Dosimetric accuracy was validated by using a 3D array detector. Dose deviations between the measured and planned doses were evaluated by gamma analysis. In addition, modulation complexity score for VMAT (MCSv) for each plan was calculated. Three-dimensional dose distributions in patient anatomy were reconstructed using 3DVH software, and clinical deviations in dosimetric parameters between the 3DVH doses and planned doses were calculated...
March 3, 2017: Journal of Radiation Research
https://www.readbyqxmd.com/read/28339108/very-high-energy-electron-vhee-beams-in-radiation-therapy-treatment-plan-comparison-between-vhee-vmat-and-ppbs
#4
Emil Schüler, Kjell Eriksson, Elin Hynning, Steven L Hancock, Susan M Hiniker, Magdalena Bazalova-Carter, Tony Wong, Quynh-Thu Le, Billy W Loo, Peter G Maxim
PURPOSE: The aim of this study was to evaluate the performance of very high energy electron beams (VHEE) beams in comparison to clinically derived treatment plans generated with volumetric modulated arc therapy (VMAT) and proton pencil beam scanning (PPBS) technology. We developed a custom optimization script that could be applied automatically across modalities to eliminate operator bias during IMRT optimization. METHODS: Four clinical cases were selected (prostate cancer, lung cancer, pediatric brain tumor, and head and neck cancer (HNC))...
March 24, 2017: Medical Physics
https://www.readbyqxmd.com/read/28338854/comparison-of-the-peripheral-doses-from-different-imrt-techniques-for-pediatric-head-and-neck-radiation-therapy
#5
Masahiko Toyota, Yasumasa Saigo, Kenta Higuchi, Takuya Fujimura, Chihaya Koriyama, Takashi Yoshiura, Suminori Akiba
Intensity-modulated radiation therapy (IMRT) can deliver high and homogeneous doses to the target area while limiting doses to organs at risk. We used a pediatric phantom to simulate the treatment of a head and neck tumor in a child. The peripheral doses were examined for three different IMRT techniques [dynamic multileaf collimator (DMLC), segmental multileaf collimator (SMLC) and volumetric modulated arc therapy (VMAT)]. Peripheral doses were evaluated taking thyroid, breast, ovary and testis as the points of interest...
February 25, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28318936/vector-model-supported-approach-in-prostate-plan-optimization
#6
Eva Sau Fan Liu, Vincent Wing Cheung Wu, Benjamin Harris, Margot Lehman, David Pryor, Lawrence Wing Chi Chan
Lengthy time consumed in traditional manual plan optimization can limit the use of step-and-shoot intensity-modulated radiotherapy/volumetric-modulated radiotherapy (S&S IMRT/VMAT). A vector model base, retrieving similar radiotherapy cases, was developed with respect to the structural and physiologic features extracted from the Digital Imaging and Communications in Medicine (DICOM) files. Planning parameters were retrieved from the selected similar reference case and applied to the test case to bypass the gradual adjustment of planning parameters...
March 17, 2017: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
https://www.readbyqxmd.com/read/28318101/individual-volume-based-3d-gamma-indices-for-pretreatment-vmat-qa
#7
Jinling Yi, Ce Han, Xiaomin Zheng, Yongqiang Zhou, Zhenxiang Deng, Congying Xie, Xiance Jin, Fu Jin
Although gamma analysis is still a widely accepted quantitative tool to analyze and report patient-specific QA for intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT), the correlation between the 2D percentage gamma passing rate (%GP), and the clinical dosimetric difference for IMRT and VMAT has been questioned. The purpose of this study was to investigate the feasibility of individual volume-based 3D gamma indices for pretreatment VMAT QA. Percentage dosimetric errors (%DE) of dose-volume histogram metrics (includes target volumes and organ at risks) between the treatment planning system and QA-reconstructed dose distribution, %GPs for individual volume and global gamma indices, as well their correlations and sensitivities were investigated for one- and two-arc VMAT plans...
March 20, 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28314877/fully-automated-vmat-treatment-planning-for-advanced-stage-nsclc-patients
#8
Giuseppe Della Gala, Maarten L P Dirkx, Nienke Hoekstra, Dennie Fransen, Nico Lanconelli, Marjan van de Pol, Ben J M Heijmen, Steven F Petit
PURPOSE: To develop a fully automated procedure for multicriterial volumetric modulated arc therapy (VMAT) treatment planning (autoVMAT) for stage III/IV non-small cell lung cancer (NSCLC) patients treated with curative intent. MATERIALS AND METHODS: After configuring the developed autoVMAT system for NSCLC, autoVMAT plans were compared with manually generated clinically delivered intensity-modulated radiotherapy (IMRT) plans for 41 patients. AutoVMAT plans were also compared to manually generated VMAT plans in the absence of time pressure...
March 17, 2017: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
https://www.readbyqxmd.com/read/28306550/female-pelvic-synthetic-ct-generation-based-on-joint-intensity-and-shape-analysis
#9
Lianli Liu, Shruti Jolly, Yue Cao, Karen Vineberg, Jeffrey A Fessler, James M Balter
Using MRI for radiotherapy treatment planning and image guidance is appealing as it provides superior soft tissue information over CT scans and avoids possible systematic errors introduced by aligning MR to CT images. This study presents a method that generates Synthetic CT (MRCT) volumes by performing probabilistic tissue classification of voxels from MRI data using a single imaging sequence (T1 Dixon). The intensity overlap between different tissues on MR images, a major challenge for voxel-based MRCT generation methods, is addressed by adding bone shape information to an intensity-based classification scheme...
April 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28306547/synthetic-ct-for-mri-based-liver-stereotactic-body-radiotherapy-treatment-planning
#10
Jeremy S Bredfeldt, Lianli Liu, Mary Feng, Yue Cao, James M Balter
A technique for generating MRI-derived synthetic CT volumes (MRCTs) is demonstrated in support of adaptive liver stereotactic body radiation therapy (SBRT). Under IRB approval, 16 subjects with hepatocellular carcinoma were scanned using a single MR pulse sequence (T1 Dixon). Air-containing voxels were identified by intensity thresholding on T1-weighted, water and fat images. The envelope of the anterior vertebral bodies was segmented from the fat image and fuzzy-C-means (FCM) was used to classify each non-air voxel as mid-density, lower-density, bone, or marrow in the abdomen, with only bone and marrow classified within the vertebral body envelope...
April 21, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28300376/moving-gpu-opencl-based-monte-carlo-dose-calculation-toward-clinical-use-automatic-beam-commissioning-and-source-sampling-for-treatment-plan-dose-calculation
#11
Zhen Tian, Yongbao Li, Nima Hassan-Rezaeian, Steve B Jiang, Xun Jia
We have previously developed a GPU-based Monte Carlo (MC) dose engine on the OpenCL platform, named goMC, with a built-in analytical linear accelerator (linac) beam model. In this paper, we report our recent improvement on goMC to move it toward clinical use. First, we have adapted a previously developed automatic beam commissioning approach to our beam model. The commissioning was conducted through an optimization process, minimizing the discrepancies between calculated dose and measurement. We successfully commissioned six beam models built for Varian TrueBeam linac photon beams, including four beams of different energies (6 MV, 10 MV, 15 MV, and 18 MV) and two flattening-filter-free (FFF) beams of 6 MV and 10 MV...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28300375/photon-optimizer-po-prevails-over-progressive-resolution-optimizer-pro-for-vmat-planning-with-or-without-knowledge-based-solution
#12
Fan Jiang, Hao Wu, Haizhen Yue, Fei Jia, Yibao Zhang
The enhanced dosimetric performance of knowledge-based volumetric modulated arc therapy (VMAT) planning might be jointly contributed by the patient-specific optimization objectives, as estimated by the RapidPlan model, and by the potentially improved Photon Optimizer (PO) algorithm than the previous Progressive Resolution Optimizer (PRO) engine. As PO is mandatory for RapidPlan estimation but optional for conventional manual planning, appreciating the two optimizers may provide practical guidelines for the algorithm selection because knowledge-based planning may not replace the current method completely in a short run...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28300367/4d-vmat-planning-and-verification-technique-for-dynamic-tracking-using-a-direct-aperture-deformation-dad-method
#13
Yongqian Zhang, Yong Yang, Weihua Fu, Xiang Li, Tianfang Li, Dwight E Heron, M Saiful Huq
We developed a four-dimensional volumetric modulated arc therapy (4D VMAT) planning technique for moving targets using a direct aperture deformation (DAD) method and investigated its feasibility for clinical use. A 3D VMAT plan was generated on a reference phase of a 4D CT dataset. The plan was composed of a set of control points including the beam angle, MLC apertures and weights. To generate the 4D VMAT plan, these control points were assigned to the closest respiratory phases using the temporal information of the gantry angle and respiratory curve...
March 2017: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297455/accuracy-of-one-algorithm-used-to-modify-a-planned-dvh-with-data-from-actual-dose-delivery
#14
Tianjun Ma, Matthew B Podgorsak, Lalith Kumaraswamy
Detection and accurate quantification of treatment delivery errors is important in radiation therapy. This study aims to evaluate the accuracy of DVH based QA in quantifying delivery errors. Eighteen previously treated VMAT plans (prostate, H&N, and brain) were randomly chosen for this study. Conventional IMRT delivery QA was done with the ArcCHECK diode detector for error-free plans and plans with the following modifications: 1) induced monitor unit differences up to ±3.0%,2) control point deletion (3, 5, and 8 control points were deleted for each arc), and 3) gantry angle shift (2° uniform shift clockwise and counterclockwise)...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297452/an-epid-based-system-for-gantry-resolved-mlc-quality-assurance-for-vmat
#15
Benjamin J Zwan, Michael P Barnes, Todsaporn Fuangrod, Cameron J Stanton, Daryl J O'Connor, Paul J Keall, Peter B Greer
Multileaf collimator (MLC) positions should be precisely and independently measured as a function of gantry angle as part of a comprehensive quality assurance (QA) program for volumetric-modulated arc therapy (VMAT). It is also ideal that such a QA program has the ability to relate MLC positional accuracy to patient-specific dosimetry in order to determine the clinical significance of any detected MLC errors. In this work we propose a method to verify individual MLC trajectories during VMAT deliveries for use as a routine linear accelerator QA tool...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297446/initial-clinical-experience-with-arccheck-for-imrt-vmat-qa
#16
Michalis Aristophanous, Yelin Suh, Pai C Chi, Luke J Whittlesey, Scott LaNeave, Mary K Martel
Many devices designed for the purpose of performing patient-specific IMRT/VMAT QA are commercially available. In this work we report our experience and initial clinical results with the ArcCHECK. The ArcCHECK consists of a cylindrical array of diode detectors measuring entry and exit doses. The measured result is a cumulative dose displayed as a 2D matrix. The detector array requires both an absolute dose calibration, and a calibration of the detector response, relative to each other. In addition to the calibrations suggested by the manufacturer, various tests were performed in order to assess its stability and performance prior to clinical introduction...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297441/comprehensive-dosimetric-planning-comparison-for-early-stage-non-small-cell-lung-cancer-with-sabr-fixed-beam-imrt-versus-vmat-versus-tomotherapy
#17
Ilma Xhaferllari, Omar El-Sherif, Stewart Gaede
Volumetric-modulated arc therapy (VMAT) is emerging as a leading technology in treating early-stage, non-small cell lung cancer (NSCLC) with stereotactic ablative radiotherapy (SABR). However, two other modalities capable of delivering intensity-modulated radiation therapy (IMRT) include fixed-beam and helical TomoTherapy (HT). This study aims to provide an extensive dosimetric comparison among these various IMRT techniques for treating early-stage NSCLC with SABR. Ten early-stage NSCLC patients were retrospectively optimized using three fixed-beam techniques via nine to eleven beams (high and low modulation step-and-shoot (SS), and sliding window (SW)), two VMAT techniques via two partial arcs (SmartArc (SA) and RapidArc (RA)), and three HT techniques via three different fan beam widths (1 cm, 2...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297427/a-comparative-study-of-identical-vmat-plans-with-and-without-jaw-tracking-technique
#18
Hao Wu, Fan Jiang, Haizhen Yue, Qiaoqiao Hu, Jian Zhang, Zhuolun Liu, Jian Gong, Sha Li, Jianhao Geng, Yibao Zhang
The unwanted radiation transmission through the multileaf collimators could be reduced by the jaw tracking technique which is commercially available on Varian TrueBeam accelerators. On the basis of identical plans, this study aims to investigate the dosimetric impact of jaw tracking on the volumetric-modulated arc therapy (VMAT) plans. Using Eclipse treatment planning system (TPS), 40 jaw-tracking VMAT plans with various tumor volumes and shapes were optimized. Fixed jaw plans were created by editing the jaw coordinates of the jaw-tracking plans while other parameters were identical...
September 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297350/impact-of-small-mu-segment-and-dose-rate-on-delivery-accuracy-of-volumetric-modulated-arc-therapy-vmat
#19
Long Huang, Tingliang Zhuang, Anthony Mastroianni, Toufik Djemil, Taoran Cui, Ping Xia
Volumetric-modulated arc therapy (VMAT) plans may require more control points (or segments) than some of fixed-beam IMRT plans that are created with a limited number of segments. Increasing number of control points in a VMAT plan for a given prescription dose could create a large portion of the total number of segments with small number monitor units (MUs) per segment. The purpose of this study is to investigate the impact of the small number MU/segment on the delivery accuracy of VMAT delivered with various dose rates...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28297346/initial-evaluation-of-automated-treatment-planning-software
#20
Dawn Gintz, Kujtim Latifi, Jimmy Caudell, Benjamin Nelms, Geoffrey Zhang, Eduardo Moros, Vladimir Feygelman
Even with advanced inverse-planning techniques, radiation treatment plan optimization remains a very time-consuming task with great output variability, which prompted the development of more automated approaches. One commercially available technique mimics the actions of experienced human operators to progressively guide the traditional optimization process with automatically created regions of interest and associated dose-volume objectives. We report on the initial evaluation of this algorithm on 10 challenging cases of locoreginally advanced head and neck cancer...
May 2016: Journal of Applied Clinical Medical Physics
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