Department of Biomolecular Mechanisms, Max Planck Institute for Medical Research, Jahnstrasse 29, 69120 Heidelberg, Germany, Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA, and RIKEN SPring-8 Center, Kouto 1-1-1, Sayo, Hyogo 679-5148, Japan. *Correspondence e-mail: [email protected], [email protected], yabashi@...

introduction: in recent decades, several monte carlo codes have been introduced for research and medical applications. these methods provide both accurate and detailed calculation of particle transport from linear accelerators. the main drawback of monte carlo techniques is the extremely long computing time that is required in order to obtain a dose distribution with good statistical accuracy. ...

background: in radiotherapy, wedge filters are used for optimizing the tumor dose distribution in patients. the attenuation in beam intensity due to the presence of wedge filter is compensated by means of a wedge factor measured at the central axis of the beam. the field size, depth and ssd dependence of wedge factor have been assessed for 9mv radiations of neptun pc linear accelerator. materia...

background : in spite of clinically useful photon and electron beams, high energy linacs produce secondary particles such as neutrons (photo-neutron production). neutrons have important roles during treatment with high energy photons in terms of protection and dose escalation. in this project, neutron dose equivalent of 18 mv varian accelerators is calculated by tld600 and tld700. materials and...

radiotherapy dose calculations can be evaluated by monte carlo (mc) simulations with acceptable accuracy for dose prediction in complicated treatment plans. in this work, standard, livermore and penelope electromagnetic (em) physics packages of geant4 application for tomographic emission (gate) 6.1 were compared versus monte carlo n-particle extended (mcnpx) 2.6 in simulation of 6 mv photon lin...

Background: Craniospinal irradiation (CSI) of medulloblastoma poses technological challenges due to the involvement of large treatment volume. Commonly, the whole treatment length is covered with two different isocentric plans in which the junction is shifted after every five fractions to overcome the possibility of hot and cold spot.Objective: This study aims to evaluate dosimetrically and cli...

An accelerator-based BNCT (Boron Neutron Capture Therapy) facility is being constructed at the Ibaraki Neutron Medical Research Center. It consists of a proton linac of 80kW beam power with 8 MeV energy, a beryllium target, and a moderator system to provide an epithermal neutron flux sufficient for patient treatment. The technology choices for this present system were driven by the need to hous...

Successful application of external photon beam therapy in oncology requires that the dose delivered by a medical linear accelerator and distributed within patient’s body is accurately calculated. Monte Carlo simulation currently most accurate method for this purpose but computationally too extensive routine clinical application. A very elaborate time-consuming part such generation full set (pha...