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Austin M Faught, Michael Trager, Fang-Fang Yin, John Kirkpatrick, Justus Adamson
PURPOSE: The recent development of multifocal stereotactic radiosurgery (SRS) using a single isocenter volumetric modulated arc theory (VMAT) technique warrants a re-examination of the quality assurance (QA) tolerances for routine mechanical QA recommended by the American Association of Physicists in Medicine Task Group Report Number 142. Multifocal SRS can result in targets with small volumes being at a large off-axis distance from the treatment isocenter. Consequently, angular errors in the collimator, patient support assembly (PSA), or gantry could have an increased impact on target coverage...
October 2016: Medical Physics
Svenja Ipsen, Ralf Bruder, Rick O'Brien, Paul J Keall, Achim Schweikard, Per R Poulsen
PURPOSE: With the trend in radiotherapy moving toward dose escalation and hypofractionation, the need for highly accurate targeting increases. While MLC tracking is already being successfully used for motion compensation of moving targets in the prostate, current real-time target localization methods rely on repeated x-ray imaging and implanted fiducial markers or electromagnetic transponders rather than direct target visualization. In contrast, ultrasound imaging can yield volumetric data in real-time (3D + time = 4D) without ionizing radiation...
October 2016: Medical Physics
Chang Heon Choi, So-Yeon Park, Jung-In Kim, Jin Ho Kim, Kyubo Kim, Joel Carlson, Jong Min Park
OBJECTIVES: To investigate the plan quality of tri-Co-60 intensity-modulated radiation therapy (IMRT) plans for spine stereotactic ablative radiotherapy (SABR). METHODS: A total of 20 patients with spine metastasis were retrospectively selected. For each patient, a tri-Co-60 IMRT plan and a volumetric modulated arc therapy (VMAT) plan were generated. The spinal cords were defined based on magnetic resonance images for the tri-Co-60 IMRT, while isotropic 1 mm margins were added to the spinal cords for the VMAT plans...
October 26, 2016: British Journal of Radiology
Kemal Ekici, Eda K Pepele, Bahaddin Yaprak, Oztun Temelli, Aysun F Eraslan, Nadir Kucuk, Ayse Y Altınok, Pelin A Sut, Ozlem D Alpak, Cemil Colak, Alpaslan Mayadagli
Various radiotherapy planning methods for T1N0 laryngeal cancer have been proposed to decrease normal tissue toxicity. We compare helical tomotherapy (HT), linac-based intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), and 3-D conformal radiotherapy (3D-CRT) techniques for T1N0 laryngeal cancer. Overall, 10 patients with T1N0 laryngeal cancer were selected and evaluated. Furthermore, 10 radiotherapy treatment plans have been created for all 10 patients, including HT, IMRT, VMAT, and 3D-CRT...
October 17, 2016: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Katia Pasciuti, Shrinivas Kuthpady, Anne Anderson, Bronagh Best, Saleem Waqar, Subhra Chowdhury
To examine tumor׳s and organ׳s response when different radiotherapy plan techniques are used. Ten patients with confirmed bladder tumors were first treated using 3-dimensional conformal radiotherapy (3DCRT) and subsequently the original plans were re-optimized using the intensity-modulated radiation treatment (IMRT) and volumetric-modulated arc therapy (VMAT)-techniques. Targets coverage in terms of conformity and homogeneity index, TCP, and organs׳ dose limits, including integral dose analysis were evaluated...
October 14, 2016: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Sara Barbiero, Alexandra Rink, Fabrizio Matteucci, David Fedele, Fabiola Paiar, Francesco Pasqualetti, Michele Avanzo
PURPOSE: To report on single-fraction stereotactic body radiotherapy (RT) (SBRT) with flattening filter (FF)-free (FFF) volumetric modulated arc therapy (VMAT) for lung cancer and to compare dosimetric results with VMAT with FF. METHODS AND MATERIALS: Overall, 25 patients were treated with 6-MV FFF VMAT (Varian TrueBeam STx LINAC) to a prescribed dose of 24Gy in a single fraction. Treatment plans were recreated using FF VMAT. Dose-volume indices, monitor units (MU), and treatment times were compared between FFF and FF VMAT techniques...
October 14, 2016: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Marcus Sonier, William Chu, Nafisha Lalani, Darby Erler, Patrick Cheung, Renee Korol
To develop a volumetric modulated arc therapy (VMAT) treatment planning solution in the treatment of primary renal cell carcinoma and oligometastatic adrenal lesions with stereotactic body radiation therapy. Single-arc VMAT plans (n = 5) were compared with clinically delivered step-and-shoot intensity-modulated radiotherapy (IMRT) with planning target volume coverage normalized between techniques. Target volume conformity, organ-at-risk (OAR) dose, treatment time, and monitor units were compared. A VMAT planning solution, created from a combination of arc settings and optimization constraints, auto-generated treatment plans in a single optimization...
October 13, 2016: Medical Dosimetry: Official Journal of the American Association of Medical Dosimetrists
Lin Xiao, Xin Yu, Wenjing Deng, Huixia Feng, Hui Chang, Weiwei Xiao, Huizhong Zhang, Shaoyan Xi, Mengzhong Liu, Yujia Zhu, Yuanhong Gao
We investigated the distribution of residual cancer cells (RCCs) within different layers of the bowel wall in surgical specimens and the value of biopsies of primary rectal lesion after preoperative volumetric modulated arc therapy (VMAT) with concurrent chemotherapy in patients with rectal cancer. Between April 2011 and April 2013, 178 patients with rectal cancer who received preoperative VMAT, concurrent chemotherapy, and surgery were evaluated; 79 of the patients received a biopsy of the primary lesion after chemoradiotherapy and prior to surgery...
October 10, 2016: Scientific Reports
Sankar Arumugam, Aitang Xing, Tony Young, David Thwaites, Lois Holloway
AIM: To study the sensitivity of three commercial dosimetric systems, Delta4, Multicube and Octavius4D, in detecting Volumetric Modulated Arc Therapy (VMAT) delivery errors. METHODS: Fourteen prostate and head and neck (H&N) VMAT plans were considered for this study. Three types of errors were introduced into the original plans: gantry angle independent and dependent MLC errors, and gantry angle dependent dose errors. The dose matrix measured by each detector system for the no-error and error introduced delivery were compared with the reference Treatment Planning System (TPS) calculated dose matrix for no-error plans using gamma (γ) analysis with 2%/2mm tolerance criteria...
October 4, 2016: Physica Medica: PM
Alba Fiorentino, Umberto Tebano, Ruggero Ruggieri, Francesco Ricchetti, Filippo Alongi
AIM: For simultaneous bilateral breast cancer (SBBC) treatment, conventional radiotherapy (RT) has a number of critical shortcomings. Thus, the usefulness of volumetric arc therapy (VMAT) for SBBC is undeniable. CASE REPORT: A 34-year-old woman with SBBC received neoadjuvant chemotherapy followed by breast-conserving surgery and bilateral lymph node dissection. Given the conservative surgery and the nodal involvement after neoadjuvant chemotherapy, bilateral adjuvant RT to the breasts and regional nodes with doses of 50 Gy in 25 fractions and a simultaneous integrated boost (SIB) of 60 Gy to the surgical bed was proposed...
September 27, 2016: Tumori
Jin Beom Chung, Sang Won Kang, Keun Yong Eom, Changhoon Song, Kyoung Sik Choi, Tae Suk Suh
The purpose of this study was to compare the performance of different commercial quality assurance (QA) systems for the pretreatment verification plan of stereotactic body radiotherapy (SBRT) with volumetric arc therapy (VMAT) technique using a flattening-filter-free beam. The verification for 20 pretreatment cancer patients (seven lung, six spine, and seven prostate cancers) were tested using three QA systems (EBT3 film, I'mRT MatriXX array, and MapCHECK). All the SBRT-VMAT plans were optimized in the Eclipse (version 11...
November 2016: Journal of Korean Medical Science
Jen-Yu Cheng, Eng-Yen Huang, Shun-Neng Hsu, Chong-Jong Wang
OBJECTIVE: To compare the dose distributions of intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) using the simultaneous integrated boost (SIB) technique to that of the traditional midline-block (MB) technique for boosting the parametrium in patients with cervical cancer. METHODS: Treatment plans using VMAT or IMRT with the SIB technique (VMAT-SIB and IMRT-SIB) and IMRT followed by the MB technique (IMRT-MB) were generated for each of 10 cervical cancer patients...
October 6, 2016: British Journal of Radiology
Heping Xu, Gillian Hatcher
AIM: This study aims to investigate whether there are dosimetric advantages to using VMAT (Volumetric Modulated Arc Therapy) for left-sided chest-wall patients over the three-dimensional conformal field-in-field (FinF) technique. BACKGROUND: There is a lack of dosimetric studies dedicated for chest-wall patients. Potential dosimetric advantage could be obtained using VMAT due to complex geometry of PTVs (Planning Target Volumes) and OARs (Organs at Risk) in chest-wall and lymph nodes...
November 2016: Reports of Practical Oncology and Radiotherapy
Jung-In Kim, Chang Heon Choi, Hong-Gyun Wu, Jin Ho Kim, Kyubo Kim, Jong Min Park
The aim of this work was to investigate correlations between 2D and quasi-3D gamma passing rates. A total of 20 patients (10 prostate cases and 10 head and neck cases, H&N) were retrospectively selected. For each patient, both intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans were generated. For each plan, 2D gamma evaluation with radiochromic films and quasi-3D gamma evaluation with fluence measurements were performed with both 2%/2 mm and 3%/3 mm criteria. Gamma passing rates were grouped together according to delivery techniques and treatment sites...
September 27, 2016: Oncotarget
Qixue Wu, Karen Chin Snyder, Chang Liu, Yimei Huang, Bo Zhao, Indrin J Chetty, Ning Wen
Treatment of patients with multiple brain metastases using a single-isocenter volumetric modulated arc therapy (VMAT) has been shown to decrease treatment time with the tradeoff of larger low dose to the normal brain tissue. We have developed an efficient Projection Summing Optimization Algorithm to optimize the treatment geometry in order to reduce dose to normal brain tissue for radiosurgery of multiple metastases with single-isocenter VMAT. The algorithm: (a) measures coordinates of outer boundary points of each lesion to be treated using the Eclipse Scripting Application Programming Interface, (b) determines the rotations of couch, collimator, and gantry using three matrices about the cardinal axes, (c) projects the outer boundary points of the lesion on to Beam Eye View projection plane, (d) optimizes couch and collimator angles by selecting the least total unblocked area for each specific treatment arc, and (e) generates a treatment plan with the optimized angles...
September 30, 2016: Scientific Reports
Tianjun Ma, Matthew B Podgorsak, Lalith K 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)...
2016: Journal of Applied Clinical Medical Physics
Benjamin J Zwan, Michael P Barnes, Todsaporn Fuangord, Cameron J Stanton, Daryl J O'Connor, Paul J Keall, Peter B Greer
Multileaf collimator (MLC) positions should be precisely and independently mea-sured 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...
2016: Journal of Applied Clinical Medical Physics
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 deliver-ing intensity-modulated radiation therapy (IMRT) include fixed-beam and helical TomoTherapy (HT). This study aims to provide an extensive dosimetric compari-son 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...
2016: Journal of Applied Clinical Medical Physics
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...
2016: Journal of Applied Clinical Medical Physics
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...
2016: Journal of Applied Clinical Medical Physics
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