Read by QxMD icon Read


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
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
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
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
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
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
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
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
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
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...
2016: Radiation Oncology
Christopher D Frisch, Jeffrey T Jacob, Matthew L Carlson, Robert L Foote, Colin L W Driscoll, Brian A Neff, Bruce E Pollock, Michael J Link
BACKGROUND: The optimum treatment for cystic vestibular schwannoma (VS) remains controversial. Anecdotally, many treating physicians feel that cystic VSs do not respond to stereotactic radiosurgery (SRS) as well as noncystic tumors. OBJECTIVE: To present outcomes after treatment of predominantly cystic VS with SRS. METHODS: A prospectively maintained clinical database of patients undergoing Gamma Knife (Elekta Instruments, Stockholm, Sweden) radiosurgery (GKRS) for VS at a single tertiary academic referral center was retrospectively reviewed...
August 4, 2016: Neurosurgery
Syed Bilal Ahmad, Arman Sarfehnia, Anthony Kim, Matt Wronski, Arjun Sahgal, Brian M Keller
PURPOSE: To quantify and explain the backscatter dose effects for clinically relevant high atomic number materials being irradiated in the presence of a 1.5 T transverse magnetic field. METHODS: Interface effects were investigated using Monte Carlo simulation techniques. We used gpumcd (v5.1) and geant4 (v10.1) for this purpose. gpumcd is a commercial software written for the Elekta AB, MRI linac. Dose was scored using gpumcd in cubic voxels of side 1 and 0.5 mm, in two different virtual phantoms of dimensions 20 × 20 × 20 cm and 5 × 5 × 13...
August 2016: Medical Physics
Martin F Fast, Tuathan P O'Shea, Simeon Nill, Uwe Oelfke, Emma J Harris
PURPOSE: To quantify the performance of the Clarity ultrasound (US) imaging system (Elekta AB, Stockholm, Sweden) for real-time dynamic multileaf collimator (MLC) tracking. METHODS: The Clarity calibration and quality assurance phantom was mounted on a motion platform moving with a periodic sine wave trajectory. The detected position of a 30 mm hypoechogenic sphere within the phantom was continuously reported via Clarity's real-time streaming interface to an in-house tracking and delivery software and subsequently used to adapt the MLC aperture...
August 2016: Medical Physics
Peter Kuess, Dietmar Georg, Hugo Palmans, Wolfgang Lechner
PURPOSE: For commercially available linear accelerators (Linacs), the electron energies of flattening filter free (FFF) and flattened (FF) beams are either identical or the electron energy of the FFF beam is increased to match the percentage depth dose curve (PDD) of the FF beam (in reference geometry). This study focuses on the primary dose components of FFF beams for both kinds of settings, studied on the same Linac. METHODS: The measurements were conducted on a VersaHD Linac (Elekta, Crawley, UK) for both FF and FFF beams with nominal energies of 6 and 10 MV...
August 2016: Medical Physics
James L Bedford, Gregory Smyth, Ian M Hanson, Alison C Tree, David P Dearnaley, Vibeke N Hansen
BACKGROUND AND PURPOSE: Delivering selected parts of volumetric modulated arc therapy (VMAT) plans using step-and-shoot intensity modulated radiotherapy (IMRT) beams has the potential to increase plan quality by allowing specific aperture positioning. This study investigates the quality of treatment plans and the accuracy of in vivo portal dosimetry in such a hybrid approach for the case of prostate radiotherapy. MATERIAL AND METHODS: Conformal and limited-modulation VMAT plans were produced, together with five hybrid IMRT/VMAT plans, in which 0%, 25%, 50%, 75% or 100% of the segments were sequenced for IMRT, while the remainder were sequenced for VMAT...
August 2016: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
Siji Cyriac Thekkedath, R Ganapathi Raman, M M Musthafa, A K Bakshi, Rupali Pal, Sandipan Dawn, Abdul Haneefa Kummali, Nagraj G Huilgol, T Palani Selvam, D Datta
AIM OF STUDY: The photo-neutron dose equivalents of 15 MV Elekta precise accelerators were measured for different depths in phantom, for various field sizes, at different distances from the isocenter in the patient plane and for various wedged fields. MATERIALS AND METHODS: Fast and thermal neutrons are measured using passive detectors such as Columbia Resin-39 and pair of thermoluminescent dosimetry (TLD) 600 and TLD 700 detector from Elekta medical linear accelerator...
April 2016: Journal of Cancer Research and Therapeutics
Carlos E Cardenas, Paige L Nitsch, Rajat J Kudchadker, Rebecca M Howell, Stephen F Kry
Out-of-field doses from radiotherapy can cause harmful side effects or eventually lead to secondary cancers. Scattered doses outside the applicator field, neutron source strength values, and neutron dose equivalents have not been broadly investigated for high-energy electron beams. To better understand the extent of these exposures, we measured out-of-field dose characteristics of electron applicators for high-energy electron beams on two Varian 21iXs, a Varian TrueBeam, and an Elekta Versa HD operating at various energy levels...
2016: Journal of Applied Clinical Medical Physics
Mariwan Baker, David T Cooper, Claus F Behrens
OBJECTIVE: In cervical radiotherapy, it is essential that the uterine position is correctly determined prior to treatment delivery. The aim of this study was to evaluate an autoscan ultrasound (A-US) probe, a motorized transducer creating three-dimensional (3D) images by sweeping, by comparing it with a conventional ultrasound (C-US) probe, where manual scanning is required to acquire 3D images. METHODS: Nine healthy volunteers were scanned by seven operators, using the Clarity(®) system (Elekta, Stockholm, Sweden)...
October 2016: British Journal of Radiology
Mariwan Baker, Claus F Behrens
BACKGROUND: In prostate radiotherapy, it is essential that the prostate position is within the planned volume during the treatment delivery. The aim of this study is to investigate whether intrafractional motion of the prostate is of clinical consequence, using a novel 4D autoscan ultrasound probe. METHODS: Ten prostate patients were ultrasound (US) scanned at the time of CT imaging and once a week during their course of radiotherapy treatment in an ethics-approved study, using the transperineal Clarity autoscan system (Clarity®, Elekta Inc...
2016: BMC Cancer
F Stieler, F Wenz, Y Abo-Madyan, B Schweizer, M Polednik, C Herskind, F A Giordano, S Mai
OBJECTIVE: The Gamma Knife Icon (Elekta AB, Stockholm, Sweden) allows frameless stereotactic treatment using a combination of cone beam computer tomography (CBCT), a thermoplastic mask system, and an infrared-based high-definition motion management (HDMM) camera system for patient tracking during treatment. We report on the first patient with meningioma at the left petrous bone treated with adaptive fractionated stereotactic radiotherapy (a-gkFSRT). METHODS: The first patient treated with Gamma Knife Icon at our institute received MR imaging for preplanning before treatment...
July 5, 2016: Strahlentherapie und Onkologie: Organ der Deutschen Röntgengesellschaft ... [et Al]
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"