Dear Editor, Over the last few years, medical LINAC manufacturers have started to offer couch tops or inserts designed for image-guided radiation therapy (IGRT). These couch tops have a homogeneous construction, with a carbon fiber shell and no metal components. Although the use of these couches may offer some advantages in image quality, it can have a potentially serious impact on skin sparing...

Purpose: To experimentally validate the Fastcat cone beam CT (CBCT) simulator against kV and MV CBCT images acquired with a Varian Truebeam linac. Methods: of Catphan 504 phantom were using 100 kVp on-board imager (OBI) 6 treatment electronic portal imaging device (EPID), respectively. The simulation was performed detailed models x-ray source, bowtie filter, high resolution voxelized virtual ph...

  Introduction:    Multileaf collimators (MLCs) are computer-controlled devices which are Useful and cost-effective tools for conformal therapy and intensity modulation radiotherapy (IMRT). Nowadays MLCs are important and standard configuration of the new medical linear accelerators which are substitute of conventional Blocks and has eliminated the ...

PURPOSE Equivalent Square (ES) enables the calculation of many radiation quantities for rectangular treatment fields, based only on measurements from square fields. While it is widely applied in radiotherapy, its accuracy, especially for extremely elongated fields, still leaves room for improvement. In this study, we introduce a novel explicit ES formula based on Weighted Power Mean (WPM) funct...

PURPOSE To create an accurate 6 MV Monte Carlo simulation phase space for the Varian TrueBeam treatment head geometry imported from CAD (computer aided design) without adjusting the input electron phase space parameters. METHODS GEANT4 v4.9.2.p01 was employed to simulate the 6 MV beam treatment head geometry of the Varian TrueBeam linac. The electron tracks in the linear accelerator were simu...

BACKGROUND To report about enhancements introduced in the GLAaS calibration method to convert raw portal imaging images into absolute dose matrices and to report about application of GLAaS to routine radiation tests for linac quality assurance procedures programmes. METHODS Two characteristic effects limiting the general applicability of portal imaging based dosimetry are the over-flattening ...

Background and purposeFast rotating closed-bore gantry linacs are ideally suited for breath-hold treatments due to reduced imaging delivery times. We evaluated the reproducibility stability of spirometer-guided breast treatments, using intra-bore surface monitoring portal on Halcyon (Varian Medical Systems).Materials methodsSeven left-sided cancer patients were treated in SDX spirometer (Dyn’R)...

AIM This work investigated the dosimetric properties of a 10-MV photon beam emitted from a medical linear accelerator (linac) with no flattening filter (FF). The aim of this study is to analyze the radiation fluence and energy emitted from the flattening filter free (FFF) linac using Monte Carlo (MC) simulations. MATERIALS AND METHODS The FFF linac was created by removing the FF from a linac ...

background: the electron contamination may reduce or even diminish the skin sparing property of the megavoltage beam. the detailed characteristics of contaminant electrons are presented for different field sizes and cases. materials and methods: the monte carlo code, mcnpx, has been used to simulate 18 mv photon beam from a varian linac-2300 accelerator. all dose measurements were carried out u...

PURPOSE Setting a proper margin is crucial for not only delivering the required radiation dose to a target volume, but also reducing the unnecessary radiation to the adjacent organs at risk. This study investigated the independent one-dimensional symmetric and asymmetric margins between the clinical target volume (CTV) and the planning target volume (PTV) for linac-based single-fraction framele...