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https://www.readbyqxmd.com/read/27903195/dosimetric-effects-of-onyx-embolization-on-gamma-knife-arteriovenous-malformation-dose-distributions
#1
David J Schlesinger, Håkan Nordström, Anders Lundin, Zhiyuan Xu, Jason P Sheehan
OBJECTIVE Patients with arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS) subsequent to embolization suffer from elevated local failure rates and differences in adverse radiation effects. Onyx is a common embolic material for AVMs. Onyx is formulated with tantalum, a high atomic number (Z = 73) element that has been investigated as a source of dosimetric uncertainty contributing to the less favorable clinical results. However, prior studies have not modeled the complicated anatomical and beam geometries characteristic of GKRS...
December 2016: Journal of Neurosurgery
https://www.readbyqxmd.com/read/27895687/commissioning-and-quality-assurance-procedures-for-the-hdr-valencia-skin-applicators
#2
REVIEW
Domingo Granero, Cristian Candela-Juan, Facundo Ballester, Zoubir Ouhib, Javier Vijande, Jose Richart, Jose Perez-Calatayud
The Valencia applicators (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden) are cup-shaped tungsten applicators with a flattening filter used to collimate the radiation produced by a high-dose-rate (HDR) (192)Ir source, and provide a homogeneous absorbed dose at a given depth. This beam quality provides a good option for the treatment of skin lesions at shallow depth (3-4 mm). The user must perform commissioning and periodic testing of these applicators to guarantee the proper and safe delivery of the intended absorbed dose, as recommended in the standards in radiation oncology...
October 2016: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/27881158/evaluation-of-daily-patient-positioning-for-radiotherapy-with-a-commercial-3d-surface-imaging-system-catalyst%C3%A2
#3
F Walter, P Freislederer, C Belka, C Heinz, M Söhn, F Roeder
BACKGROUND: To report our initial clinical experience with the novel surface imaging system Catalyst™ (C-RAD AB, Sweden) in connection with an Elekta Synergy linear accelerator for daily patient positioning in patients undergoing radiation therapy. METHODS: We retrospectively analyzed the patient positioning of 154 fractions in 25 patients applied to thoracic, abdominal, and pelvic body regions. Patients were routinely positioned based on skin marks, shifted to the calculated isocenter position and treated after correction via cone beam CT which served as gold standard...
November 24, 2016: Radiation Oncology
https://www.readbyqxmd.com/read/27876604/predictors-and-patterns-of-regional-recurrence-following-lung-sbrt-a-report-from-the-elekta-lung-research-group
#4
Meredith E Giuliani, Andrew Hope, Victor Mangona, Matthias Guckenberger, Frederick Mantel, Heike Peulen, Jan-Jakob Sonke, José Belderbos, Maria Werner-Wasik, Hong Ye, Inga S Grills
INTRODUCTION: The objective of this study was to determine the predictors and patterns of regional recurrence (RR) following stereotactic body radiotherapy (SBRT) for primary lung cancers. MATERIAL AND METHODS: Details of patient factors, treatment, and outcome factors were extracted from a multi-institutional (5) database. All events were calculated from the end of radiotherapy. Estimates of local recurrence, RR, and distant metastases (DM) were calculated using the competing risk method...
October 26, 2016: Clinical Lung Cancer
https://www.readbyqxmd.com/read/27851877/understanding-the-continuum-of-radionecrosis-and-vascular-disorders-in-the-brain-following-gamma-knife-irradiation-an-mri-study
#5
Julie Constanzo, Laurence Masson-Côté, Luc Tremblay, Jérémie P Fouquet, Philippe Sarret, Sameh Geha, Kevin Whittingstall, Benoit Paquette, Martin Lepage
PURPOSE: The radiation dose delivered to brain tumors is limited by the possibility to induce vascular damage and necrosis in surrounding healthy tissue. In the present study, we assessed the ability of MRI to monitor the cascade of events occurring in the healthy rat brain after stereotactic radiosurgery, which could be used to optimize the radiation treatment planning. METHODS: The primary somatosensory forelimb area (S1FL) and the primary motor cortex in the right hemisphere of Fischer rats (n = 6) were irradiated with a single dose of Gamma Knife radiation (Leksell Perfexion, Elekta AG, Stockholm, Sweden)...
November 10, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27830373/precision-of-mri-ultrasound-fusion-biopsy-in-prostate-cancer-diagnosis-an-ex-vivo-comparison-of-alternative-biopsy-techniques-on-prostate-phantoms
#6
N Westhoff, F P Siegel, D Hausmann, M Polednik, J von Hardenberg, M S Michel, M Ritter
PURPOSE: Comparing the accuracy of MRI/ultrasound-guided target-biopsy by transrectal biopsy (TRB) with elastic versus rigid image fusion versus transperineal biopsy (TPB) with rigid image fusion in a standardized setting. METHODS: Target-biopsy of six differently sized and located lesions was performed on customized CIRS 070L prostate phantoms. Lesions were only MRI-visible. After prior MRI for lesion location, one targeted biopsy per lesion was obtained by TRB with elastic image fusion with Artemis™ (Eigen, USA), TRB with rigid image fusion with real-time virtual sonography (Hitachi, Japan) and TPB with rigid image fusion with a brachytherapy approach (Elekta, Sweden), each on a phantom of 50, 100 and 150 ml prostate volume...
November 9, 2016: World Journal of Urology
https://www.readbyqxmd.com/read/27819251/reconstruction-of-high-resolution-mlc-leaf-positions-using-a-low-resolution-detector-for-accurate-3d-dose-reconstruction-in-imrt
#7
R Visser, J Godart, D J L Wauben, J A Langendijk, A A Van't Veld, E W Korevaar
In pre-treatment dose verification, low resolution detector systems are unable to identify shifts of individual leafs of high resolution multi leaf collimator (MLC) systems from detected changes in the dose deposition. The goal of this study was to introduce an alternative approach (the shutter technique) combined with a previous described iterative reconstruction method to accurately reconstruct high resolution MLC leaf positions based on low resolution measurements. For the shutter technique, two additional radiotherapy treatment plans (RT-plans) were generated in addition to the original RT-plan; one with even MLC leafs closed for reconstructing uneven leaf positions and one with uneven MLC leafs closed for reconstructing even leaf positions...
December 7, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27806611/accuracy-of-dose-calculations-on-kv-cone-beam-ct-images-of-lung-cancer-patients
#8
Mariska de Smet, Danny Schuring, Sebastiaan Nijsten, Frank Verhaegen
PURPOSE: To develop a clinically feasible method for dose calculations on cone beam CT (CBCT) images of two different vendors, and to determine the accuracy of these dose calculations for lung cancer patients. METHODS: Lung cancer patients with CBCT imaging (n = 10 for Elekta, n = 6 for Varian) and a repeated planning CT scan on the same day were selected. For CBCT dose calculations, an adapted Hounsfield units-to-mass density table (HU table) was used which was obtained by comparing CT values of corresponding points on the CBCT and the repeated planning CT scan...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27806589/real-time-4d-dose-reconstruction-for-tracked-dynamic-mlc-deliveries-for-lung-sbrt
#9
Cornelis Ph Kamerling, Martin F Fast, Peter Ziegenhein, Martin J Menten, Simeon Nill, Uwe Oelfke
PURPOSE: This study provides a proof of concept for real-time 4D dose reconstruction for lung stereotactic body radiation therapy (SBRT) with multileaf collimator (MLC) tracking and assesses the impact of tumor tracking on the size of target margins. METHODS: The authors have implemented real-time 4D dose reconstruction by connecting their tracking and delivery software to an Agility MLC at an Elekta Synergy linac and to their in-house treatment planning software (TPS)...
November 2016: Medical Physics
https://www.readbyqxmd.com/read/27790075/practical-issues-regarding-angular-and-energy-response-in-in-vivo-intraoperative-electron-radiotherapy-dosimetry
#10
Juan López-Tarjuelo, Ana Bouché-Babiloni, Virginia Morillo-Macías, Agustín Santos-Serra, Carlos Ferrer-Albiach
AIM: To estimate angular response deviation of MOSFETs in the realm of intraoperative electron radiotherapy (IOERT), review their energy dependence, and propose unambiguous names for detector rotations. BACKGROUND: MOSFETs have been used in IOERT. Movement of the detector, namely rotations, can spoil results. MATERIALS AND METHODS: We propose yaw, pitch, and roll to name the three possible rotations in space, as these unequivocally name aircraft rotations...
January 2017: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/27742559/management-of-independent-motion-between-multiple-targets-in-lung-cancer-radiation-therapy
#11
Feng Liu, An Tai, Ergun Ahunbay, Elizabeth Gore, Candice Johnstone, X Allen Li
PURPOSE: To quantify interfractional independent motions between multiple primary targets in radiation therapy (RT) of lung cancer and to study the dosimetric benefits of an online adaptive replanning method to account for these variations. METHODS AND MATERIALS: Ninety-five on-treatment diagnostic-quality computed tomography (CT) scans acquired for 9 lung cancer patients treated with image-guided RT (IGRT) using a CT-on-rails (CTVision, Siemens) were analyzed. On each on-treatment CT set, contours of the targets (gross tumor volume, clinical target volume, or involved nodes), and organs at risk were generated by populating the planning contours using an autosegmentation tool (ABAS, Elekta) with manual editing...
September 2, 2016: Practical Radiation Oncology
https://www.readbyqxmd.com/read/27739408/transit-dose-comparisons-for-60-co-and-192-ir-hdr-sources
#12
Vicent Giménez-Alventosa, Javier Vijande, Facundo Ballester, Jose Perez-Calatayud
The goal of this study is to evaluate the ambient dose due to the transit of high dose rate (HDR) (60)Co sources along a transfer tube as compared to (192)Ir ones in a realistic clinical scenario. This goal is accomplished by evaluating air-kerma differences with Monte Carlo calculations using PENELOPE2011. Scatter from both the afterloader and the patient was not taken into account. Two sources, mHDR-v2 and Flexisource Co-60, (Elekta Brachytherapy, Veenendaal, the Netherlands) have been considered. These sources were simulated within a standard transfer tube located in an infinite air phantom...
October 14, 2016: Journal of Radiological Protection: Official Journal of the Society for Radiological Protection
https://www.readbyqxmd.com/read/27721671/prostate-intensity-modulated-radiotherapy-planning-in-seven-mouse-clicks-development-of-a-class-solution-for-cancer
#13
Maree Wood, Amara Fonseca, David Sampson, Andrew Kovendy, Justin Westhuyzen, Thomas Shakespeare, Kirsty Turnbull
AIM: The aim of the retrospective study was to develop a planning class solution for prostate intensity-modulated radiotherapy (IMRT) that achieved target and organs-at-risk (OAR) doses within acceptable departmental protocol criteria using the Monaco treatment planning system (Elekta-CMS Software, MO, USA). BACKGROUND: Advances in radiation therapy technology have led to a re-evaluation of work practices. Class solutions have the potential to produce highly conformal plans in a time-efficient manner...
November 2016: Reports of Practical Oncology and Radiotherapy
https://www.readbyqxmd.com/read/27694708/sharpening-peripheral-dose-gradient-via-beam-number-enhancement-from-patient-head-tilt-for-stereotactic-brain-radiosurgery
#14
Joshua Chiu, Marlon Pierce, Steve E Braunstein, Philip V Theodosopoulos, Michael W McDermott, Penny K Sneed, Lijun Ma
Sharp dose fall-off is the hallmark of brain radiosurgery for the purpose of delivering high dose radiation to the target while minimizing peripheral dose to regional normal brain tissue. In this study, a technique was developed to enhance the peripheral dose gradient by magnifying the total number of beams focused toward each isocenter through pre-programmed patient head tilting. This technique was tested in clinical settings on a dedicated brain radiosurgical system (GKPFX, Gamma Knife Perfexion, Elekta Oncology) by comparing dosimetry as well as delivery efficiency for 20 radiosurgical cases previously treated with the system...
October 3, 2016: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/27685137/comparison-of-automatic-image-registration-uncertainty-for-three-igrt-systems-using-a-male-pelvis-phantom
#15
Jeffrey Barber, Jonathan R Sykes, Lois Holloway, David I Thwaites
A series of phantom images using the CIRS Virtual Human Male Pelvis was acquired across available dose ranges for three image-guided radiotherapy (IGRT) imaging systems: Elekta XVI CBCT, Varian TrueBeam CBCT, and TomoTherapy MV CT. Each image was registered to a fan-beam CT within the XVI software 100 times with random initial offsets. The residual registration error was analyzed to assess the role of imaging hardware and reconstruction in the uncertainty of the IGRT process. Residual translation errors were similar for all systems and < 0...
2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27685127/surface-dose-variations-in-6-and-10-mv-flattened-and-flattening-filter-free-fff-photon-beams
#16
Jason Cashmore
As the use of linear accelerators operating in flattening filter-free (FFF) modes becomes more widespread, it is important to have an understanding of the surface doses delivered to patients with these beams. Flattening filter removal alters the beam quality and relative contributions of low-energy X-rays and contamination electrons in the beam. Having dosimetric data to describe the surface dose and buildup regions under a range of conditions for FFF beams is important if clinical decisions are to be made...
2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27685101/radiation-leakage-dose-from-elekta-electron-collimation-system
#17
Garrett M Pitcher, Kenneth R Hogstrom, Robert L Carver
This study provided baseline data required for a greater project, whose objective was to design a new Elekta electron collimation system having significantly lighter electron applicators with equally low out-of field leakage dose. Specifically, off-axis dose profiles for the electron collimation system of our uniquely configured Elekta Infinity accelerator with the MLCi2 treatment head were measured and calculated for two primary purposes: 1) to evaluate and document the out-of-field leakage dose in the patient plane and 2) to validate the dose distributions calculated using a BEAMnrc Monte Carlo (MC) model for out-of-field dose profiles...
2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/27648089/novel-simple-templates-for-reproducible-positioning-of-skin-applicators-in-brachytherapy
#18
REVIEW
Silvia Rodríguez Villalba, Maria Jose Perez-Calatayud, Juan Antonio Bautista, Vicente Carmona, Francisco Celada, Alejandro Tormo, Teresa García-Martinez, José Richart, Manuel Santos Ortega, Magda Silla, Facundo Ballester, Jose Perez-Calatayud
PURPOSE: Esteya and Valencia surface applicators are designed to treat skin tumors using brachytherapy. In clinical practice, in order to avoid errors that may affect the treatment outcome, there are two issues that need to be carefully addressed. First, the selected applicator for the treatment should provide adequate margin for the target, and second, the applicator has to be precisely positioned before each treatment fraction. In this work, we describe the development and use of a new acrylic templates named Template La Fe-ITIC...
August 2016: Journal of Contemporary Brachytherapy
https://www.readbyqxmd.com/read/27593799/computerized-tomography-guided-stereotactic-biopsy-of-intracranial-lesions-report-of-consecutive-500-cases
#19
Songül Meltem Can, Osman Nuri Türkmenoğlu, Canan Tanik, Ender Uysal, Barış Özöner, Saime Ayça Kaldirimoğlu, Ahmet Murat Müslüman, Adem Yilmaz, Halit Çavuşoğlu, Çiçek Bayindir, Yunus Aydin
AIM: CT-guided stereotactic brain biopsy has been performed in our clinic since March 1998. In this prospective study, we examined the patient data undergoing stereotactic biopsy and the results of biopsies in consecutive 500 patients. MATERIAL AND METHODS: Between the dates of March 1998 and January 2015, CT guided stereotactic biopsies were performed by using the Leksell stereotactic frame system (Elekta Instruments EU, Sweden) in 500 patients. A total of 512 procedures were performed in patients consisting of 184 females (36...
January 25, 2016: Turkish Neurosurgery
https://www.readbyqxmd.com/read/27577561/simultaneous-integrated-boost-sib-radiation-therapy-of-right-sided-breast-cancer-with-and-without-flattening-filter-a-treatment-planning-study
#20
Johannes Maier, Bernadette Knott, Manuel Maerz, Rainer Loeschel, Oliver Koelbl, Barbara Dobler
BACKGROUND: The aim of the study was to compare the two irradiation modes with (FF) and without flattening filter (FFF) for three different treatment techniques for simultaneous integrated boost radiation therapy of patients with right sided breast cancer. METHODS: An Elekta Synergy linac with Agility collimating device is used to simulate the treatment of 10 patients. Six plans were generated in Monaco 5.0 for each patient treating the whole breast and a simultaneous integrated boost (SIB) volume: intensity modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT) and a tangential arc VMAT (tVMAT), each with and without flattening filter...
August 31, 2016: Radiation Oncology
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