PURPOSE Lipiodol, which was used in transcatheter arterial chemoembolization before liver stereotactic body radiation therapy (SBRT), remains in SBRT. Previous we reported the dose enhancement in Lipiodol using 10 MV (10×) FFF beam. In this study, we compared the dose enhancement in Lipiodol and evaluated the probability of electron generation (PEG) for the dose enhancement using flattening fil...

Locoregional treatment of breast cancer involves adjacent, half blocked fields matched at isocenter. The objective of this work is to study the dosimetric effects of the uncertainties in jaw positioning for such a case, and how a treatment planning protocol including adjacent field overlap of 1 mm affects the dose distribution. A representative treatment plan, involving 6 and 15 photon beams, f...

Treating shallow tumors with a homogeneous dose while simultaneously minimizing the dose to distal critical organs remains a challenge in radiotherapy. One promising approach is modulated electron radiotherapy (MERT). Due to the scattering properties of electron beams, the commercially provided secondary and tertiary photon collimation systems are not conducive for electron beam delivery when s...

IMRT QA requires, among other tests, a time-consuming process of measuring the absorbed dose, at least to a point, in a high-dose, low-dose-gradient region. Some clinics use a technique of measuring this dose with all beams delivered at a single gantry angle (collapsed delivery), as opposed to the beams delivered at the planned gantry angle (rotated delivery). We examined, established, and opti...

The objective of this work is to quantify the systematic errors introduced by the common assumption of invariant secondary electron spectra with changing field sizes, as relevant to stereotactic radiotherapy and other treatment modes incorporating small beam segments delivered with a linac-based stereotactic unit. The EGSnrc/BEAMnrc Monte Carlo radiation transport code was used to construct a d...

discrete element method (dem) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by dem simulation. in this article, a new approach was used to assess the main paramet...

potassium channels allow potassium flux and are essential for the generation of electric current acrossexcitable membranes. potassium channels are also the targets of various intracellular controlmechanisms; such that the suboptimal regulation of channel function might be related to pathologicalconditions. realistic studies of ion current in biologic channels present a major challenge for compu...

objective: in this trial, we intend to assess the effect of simulation-based education approach on advanced cardiovascular life support skills among medical students. methods: through convenient sampling method, 40 interns of mashhad university of medical sciences in their emergency medicine rotation (from september to december 2012) participated in this study. advanced cardiovascular life supp...

breaking waves have ability to transport large quantities of sediment and significant impact on coastal structures morphology. hence, modeling of wave breaking is an important subject in coastal and marine engineering. in this research, the periodic wave breaking process on a plane slope is studied experimentally and numerically. laboratory experiments were conducted to record water surface ele...