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https://www.readbyqxmd.com/read/28173979/image-movement-of-the-elekta-epid-during-gantry-rotation-effects-on-the-verification-of-dose-distributions
#1
J Köhn, J Licher, M Mielke, B Loutfi-Krauss, N Blümer, B Heine, C Rödel, C Scherf, U Ramm
PURPOSE: The use of Electronic Portal Imaging Devices (EPIDs) to acquire dosimetric information, especially for 3D-back-projection, has been increasingly extended. For a precise back-projection, the accurate knowledge of the movement characteristics of the EPID during gantry rotation is an essential requirement. METHODS AND MATERIAL: Measurements were conducted with different alignments of steel balls, which were mounted on the treatment table to avoid secondary effects such as the mechanical sag of gantry or jaws...
February 4, 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28168813/the-impacts-of-mid-treatment-cbct-guided-patient-repositioning-on-target-coverage-during-lung-vmat
#2
Dominique Mathieu, Marie-Pierre Campeau, Stéphane Bedwani, David Roberge, Robert Doucet, Karim Zerouali, Houda Bahig, Toni Vu, Louise Lambert, Laura Masucci, Edith Filion
INTRODUCTION: The purpose of this study is quantify intrafraction motion (IFM) during lung volumetric-modulated arc therapy (VMAT) and evaluate the impact of mid-treatment cone beam computed tomography (CBCT)-guided patient repositioning on target coverage. METHOD: This analysis included lung tumours treated with VMAT to 50-60 Gy in 3-5 fractions. Treatment planning was based on four-dimensional CT scans from which internal tumour volumes (ITV) were derived. An isotropic 5 mm margin was added to obtain the final planning target volume (PTV)...
February 7, 2017: Journal of Medical Imaging and Radiation Oncology
https://www.readbyqxmd.com/read/28168125/role-of-gamma-knife%C3%A2-radiosurgery-for-the-treatment-of-brain-metastases-from-gynecological-cancers
#3
Andrew Keller, Rahim Ismail, Peter S Potrebko, Julie Pepe, Meiling Wu, Kunal Saigal, Matthew Biagioli, Ravi Shridhar, Robert Holloway, Melvin Field, Nikhil G Rao
OBJECTIVE: Gamma Knife(®) (GK) (Elekta Instruments, Stockholm, Sweden) radiosurgery is well established for treatment of brain metastases. There are limited data on patients treated with GK from gynecological cancers. The authors sought to determine the effectiveness of the GK in patients with brain metastases from gynecological cancers. METHODS: An IRB-approved database was queried for patients with gynecologic cancers treated with GK between June 1996 and May 2016...
December 31, 2016: Curēus
https://www.readbyqxmd.com/read/28139424/the-impact-of-active-breathing-control-on-internal-mammary-lymph-node-coverage-and-normal-tissue-exposure-in-breast-cancer-patients-planned-for-left-sided-postmastectomy-radiation-therapy
#4
Aisling Barry, Kathy Rock, Claudio Sole, Mohammad Rahman, Melania Pintilie, Grace Lee, Anthony Fyles, C Anne Koch
PURPOSE: The purpose of this study was to evaluate the impact of the active breathing control (ABC) technique on IMN coverage and organs at risk in patients planned for postmastectomy radiation therapy (PMRT), with the inclusion of the internal mammary lymph nodes (IMNs). The effect of body mass index (BMI) on recorded dosimetric parameters was examined in the same patient cohort. METHODS AND MATERIALS: Fifty left-sided postmastectomy patients with breast cancer who underwent free-breathing (FB) and ABC-Elekta CT simulation scans were selected at random from an institutional breast cancer database between 2008 and 2014...
December 7, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/28115958/failure-mode-and-effects-analysis-of-skin-electronic-brachytherapy-using-esteya-%C3%A2-unit
#5
Blanca Ibanez-Rosello, Juan Antonio Bautista-Ballesteros, Jorge Bonaque, Francisco Celada, Françoise Lliso, Vicente Carmona, Jose Gimeno-Olmos, Zoubir Ouhib, Joan Rosello, Jose Perez-Calatayud
PURPOSE: Esteya(®) (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden) is an electronic brachytherapy device used for skin cancer lesion treatment. In order to establish an adequate level of quality of treatment, a risk analysis of the Esteya treatment process has been done, following the methodology proposed by the TG-100 guidelines of the American Association of Physicists in Medicine (AAPM). MATERIAL AND METHODS: A multidisciplinary team familiar with the treatment process was formed...
December 2016: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/28102956/experimental-verification-of-4d-monte-carlo-simulations-of-dose-delivery-to-a-moving-anatomy
#6
Sara Gholampourkashi, Miro Vujicic, Jason Belec, Joanna E Cygler, Emily Heath
PURPOSE: To evaluate a novel 4D Monte Carlo simulation tool by comparing calculations to physical measurements using a respiratory motion phantom. METHODS: We used a dynamic Quasar phantom in both stationary and breathing states (sinusoidal motion of amplitude of 1.8 cm and period of 3.3 s) for dose measurements on an Elekta Agility linear accelerator. Gafchromic EBT3 film and the RADPOS 4D dosimetry system were placed inside the lung insert of the phantom to measure dose profiles and point-dose values at the center of the spherical tumor inside the insert...
January 2017: Medical Physics
https://www.readbyqxmd.com/read/28078405/-radiosurgery-and-fractionated-stereotactic-radiotherapy-of-vestibular-schwannoma
#7
K Hamm, H-U Herold, G Surber, S Rosahl
Management of vestibular schwannoma (VS) should always be interdisciplinary and results better than the natural course. Particularly in small VS, either microsurgical resection or radiosurgery (RS) can be employed. RS is a special method (initially only possible stereotactically) for delivering high-precision radiation from many directions to the target point (the isocenter) in a single high dose. With the development of three different systems-Gamma Knife (Elekta, Stockholm, Sweden), special linear accelerators, and CyberKnife (Accuray, Sunnyvale, CA, USA)-the options were extended to 1-5 fractions for RS and multisession RS (msRS), and to up to 6 weeks of conventional fractionation as stereotactic radiotherapy (SRT)...
January 11, 2017: HNO
https://www.readbyqxmd.com/read/28073637/variable-angle-stereo-imaging-for-rapid-patient-position-correction-in-an-in-house-real-time-position-monitoring-system
#8
Sankar Arumugam, Mark Sidhom, Daniel Truant, Aitang Xing, Mark Udovitch, Lois Holloway
PURPOSE: To develop and validate a variable angle stereo image based position correction methodology in an X-ray based in-house online position monitoring system. MATERIALS AND METHODS: A stereo imaging module that enables 3D position determination and couch correction of the patient based on images acquired at any arbitrary angle and arbitrary angular separation was developed and incorporated to the in-house SeedTracker real-time position monitoring system. The accuracy of the developed system was studied by imaging an anthropomorphic phantom implanted with radiopaque markers set to known offset positions from its reference position in an Elekta linear accelerator (LA) and associated XVI imaging system...
January 2017: Physica Medica: PM
https://www.readbyqxmd.com/read/28048890/su-g-tep1-05-development-and-clinical-introduction-of-automated-radiotherapy-treatment-planning-for-prostate-cancer
#9
D Winkel, G H Bol, B van Asselen, J Hes, V Scholten, Lgw Kerkmeijer, B W Raaymakers
PURPOSE: To develop an automated radiotherapy treatment planning and optimization workflow for prostate cancer in order to generate clinical treatment plans. METHODS: A fully automated radiotherapy treatment planning and optimization workflow was developed based on the treatment planning system Monaco (Elekta AB, Stockholm, Sweden). To evaluate our method, a retrospective planning study (n=100) was performed on patients treated for prostate cancer with 5 field intensity modulated radiotherapy, receiving a dose of 35×2Gy to the prostate and vesicles and a simultaneous integrated boost of 35×0...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048877/su-g-brb-08-investigation-on-the-magnetic-field-effect-on-tlds-oslds-and-gafchromic-films-using-an-mr-linac
#10
Z Wen, J Wang, W Jiang, D O'Brien, G Sawakuchi, G Ibbott
PURPOSE: To investigate whether a strong magnetic field (B=1.5 T) can affect dose responses of thermoluminescent dosimeters (TLDs), optically stimulated luminescence dosimeters (OSLDs) and Gafchromic films using an MR-Linac (Elekta) before and after the magnet was ramped down from 1.5 T to 0 T. METHODS: Three types of dosimeters (TLDs, OSLDs, EBT3 films) were divided into two groups. Group 1 was first irradiated in a phantom of Solid Water slabs (Standard Imaging) inside a B=1...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048863/su-f-j-105-towards-a-novel-treatment-planning-pipeline-delivering-pareto-optimal-plans-while-enabling-inter-and-intrafraction-plan-adaptation
#11
C Kontaxis, S Breedveld, G Bol, A Sharfo, B Heijmen, J Lagendijk, B Raaymakers
PURPOSE: To develop a new IMRT treatment planning methodology suitable for the new generation of MR-linear accelerator machines. The pipeline is able to deliver Pareto-optimal plans and can be utilized for conventional treatments as well as for inter- and intrafraction plan adaptation based on real-time MR-data. METHODS: A Pareto-optimal plan is generated using the automated multicriterial optimization approach Erasmus-iCycle. The resulting dose distribution is used as input to the second part of the pipeline, an iterative process which generates deliverable segments that target the latest anatomical state and gradually converges to the prescribed dose...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048861/su-g-jep1-09-evaluation-of-transperineal-ultrasound-imaging-as-a-potential-solution-for-target-tracking-during-ablative-body-radiotherapy-for-prostate-cancer
#12
M Najafi, B Han, D Cooper, S Hancock, D Hristov
PURPOSE: Prostate SABR is emerging as a clinically viable, potentially cost effective alternative to prostate IMRT but its adoption is contingent on providing solutions for accurate tracking during beam delivery. Our goal is to evaluate the performance of the Clarity Autoscan ultrasound monitoring system for inter-fractional prostate motion tracking in both phantoms and in-vivo. METHODS: In-vivo evaluation was performed under IRB protocol to allow data collection in prostate patients treated with VMAT whereby prostate was imaged through the acoustic window of the perineum...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048859/su-g-jep4-12-real-time-organ-motion-monitoring-using-ultrasound-and-kv-fluoroscopy-during-lung-sbrt-delivery
#13
E Omari, A Tai, D Cooper, M Lachaine, X Li
PURPOSE: Real-time ultrasound monitoring during SBRT is advantageous in understanding and identifying motion irregularities which may cause geometric misses. In this work, we propose to utilize real-time ultrasound to track the diaphragm in conjunction with periodical kV fluoroscopy to monitor motion of tumor or landmarks during SBRT delivery. METHODS: Transabdominal Ultrasound (TAUS) b-mode images were collected from 10 healthy volunteers using the Clarity Autoscan System (Elekta)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048837/mo-de-202-01-image-guided-focused-ultrasound-surgery-and-therapy
#14
K Farahani
At least three major trends in surgical intervention have emerged over the last decade: a move toward more minimally invasive (or non-invasive) approach to the surgical target; the development of high-precision treatment delivery techniques; and the increasing role of multi-modality intraoperative imaging in support of such procedures. This symposium includes invited presentations on recent advances in each of these areas and the emerging role for medical physics research in the development and translation of high-precision interventional techniques...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048836/su-f-j-30-application-of-intra-fractional-imaging-for-pretreatment-cbct-of-breath-hold-lung-sbrt
#15
D Cao, M Jermoumi, V Mehta, D Shepard
PURPOSE: Clinical implementation of gated lung SBRT requires tools to verify the accuracy of the target positioning on a daily basis. This is a particular challenge on Elekta linacs where the XVI imaging system does not interface directly to any commercial gating solution. In this study, we used the Elekta's intra-fractional imaging functionality to perform the pretreatment CBCT verifications and evaluated both the image quality and gating accuracy. METHODS: To use intrafraction imaging tools for pretreatment verifications, we planned a 360-degree arc with 1mmx5mm MLC opening...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048793/su-f-t-72-experimental-determination-of-the-positionuncertainties-for-roos-ionization-chambers-in-clinical-electron-beams
#16
P von Voigts-Rhetz, T Pretzsch, D Czarnecki, H Vorwerk, K Zink
PURPOSE: National and international dosimetry protocols assume a position accuracy for ionization chambers of less than 0.2mm. To follow this precept the manufacturer PTW-Freiburg introduced a positioning assistance system (TRUFIX) for their particular ion chambers. Aim of this study is an experimental investigation of the positioning uncertainties for ROOS-type ionization chambers. METHODS: For all measurements a linear accelerator Elekta Synergie was used. The experiments were performed in a water-phantom...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048766/su-g-bra-16-target-dose-comparison-for-dynamic-mlc-tracking-and-mid-ventilation-planning-in-lung-radiotherapy-subject-to-intrafractional-baseline-drifts
#17
M J Menten, M F Fast, S Nill, U Oelfke
PURPOSE: Lung tumor motion during radiotherapy can be accounted for by expanded treatment margins, for example using a mid-ventilation planning approach, or by localizing the tumor in real-time and adapting the treatment beam with multileaf collimator (MLC) tracking. This study evaluates the effect of intrafractional changes in the average tumor position (baseline drifts) on these two treatment techniques. METHODS: Lung stereotactic treatment plans (9-beam IMRT, 54Gy/3 fractions, mean treatment time: 9...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048764/tu-d-202-00-rest-in-peace-itv
#18
Marcel van Herk
: Respiratory motion has long been recognized as an important factor affecting the precision of radiotherapy. After the introduction of the 4D CT to visualize the respiratory motion in 3D, the internal target volume (ITV) has been widely adopted as simple method to take the motion into account in treatment planning and delivery. The ITV is generated as the union of the CTVs as the patient goes through the respiratory cycle. Many issues have been identified with the ITV. In this session three alternatives for the ITV will be discussed: 1) An alternative motion-inclusive approach with better imaging and smaller margins, called mid-position CT...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048752/tu-a-brb-02-panel-member
#19
L Ma
: Brain stereotactic radiosurgery (SRS) and spine stereotactic body radiation therapy (SBRT) are commonly treated by a multidisciplinary team of neurosurgeons, radiation oncologists, and medical physicists. However the treatment objectives, constraints, and technical considerations involved can be quite different between the two techniques. In this interactive session an expert panel of speakers will present clinical brain SRS and spine SBRT cases in order to demonstrate real-world considerations for ensuring safe and accurate treatment delivery and to highlight the significant differences in approach for each treatment site...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048689/su-f-t-294-the-analysis-of-gamma-criteria-for-delta4-dosimetry-using-statistical-process-control
#20
S Cho, S Ahn, J Kim, K Park, W Choi, H Lee, E Lee, J Yoon, K Keum
PURPOSE: To evaluate the sensitivity of gamma criteria for patient-specific volumetric modulated arc therapy(VMAT) quality assurance of the Delta(4) dosimetry program using the statistical process control(SPC) methodology. METHODS: The authors selected 20 patient-specific VMAT QA cases which were undertaken MapCHECK and ArcCHECK with gamma pass rate better than 97%. The QAs data were collected Delta4 Phantom+ and Elekta Agility six megavolts without using an angle incrementer...
June 2016: Medical Physics
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