Acquisition of quasi-monoenergetic ("pristine") depth-dose curves is an essential task in the frame of commissioning and quality assurance of a proton therapy treatment head. For pencil beam scanning delivery modes this is often accomplished by measuring the integral ionization in a plane perpendicular to the axis of an unscanned beam. We focus on the evaluation of three integral detectors: two...

in almost all of the present mathematical models, the upstream subbasins, with overland flow as the dominant type of flow, are simulated as a rectangular plane. however, the converging plane is the closest shape to an actual upstream subbasin. the intricate nature of the governing equations of the overland flow on a converging plane is the cause of prolonged absence of an analytical or semi ana...

Introduction: Electronic portal imaging devices (EPIDs) could be used to dose verification of radiotherapy treatment plans. In vivo dose verification is performed to reduce differences found between dose delivered to the patient and the prescribed dose. The aim of this study was to perform a fast and efficient technique for the verification of delivered dose to the patient usin...

A tandem ionization chamber, developed at the Instituto de Pesquisas Energéticas e Nucleares (IPEN), for X radiation beams, radiotherapy level, was applied into a quality control program of the Calibration Laboratory of IPEN. This ionization chamber is composed by two ionization chambers, with a volume of 0.6 cm each one. Its inner plane-parallel electrodes and guard rings are made of different...

An in-line ionization chamber has been developed for the real-time measurement of the absolute intensity of the pulsed parametric X-ray (PXR) beam during irradiation experiments. The quasi-monochromatic PXR generating system was developed at the Laboratory for Electron Beam Research and Application (LEBRA) in Nihon University. In contrast to typical narrow X-ray beams in synchrotron radiation f...

Introduction For dose measurement in Megavoltage (MV) photon beams with ion chambers, the effect of volume occupied by the air cavity is not negligible. Therefore, the result of measurement should be corrected with a displacement perturbation correction factor (Pdis) or using an effective point of measurement (EPOM). The aim of this study is to calculate the EPOM for cylindrical ion chamber and...

Current dosimetry protocols (AAPM, IAEA, DIN) recommend the use of parallel-plate ionization chambers for the measurement of absorbed dose-to-water in clinical electron beams. For well-guarded plane-parallel chambers, it is assumed that the perturbation correction pQ is unity for all electron energies. In this study, we present detailed Monte Carlo simulations with the EGSnrc code for the widel...

This report outlines the possibilities to be found using one or more diffraction-limited high-quality light beams to activate a weakly absorbing gas in a regime where the diffraction spread can be controlled by converging optical devices to within a ratio ofJ2 of the minimum at the beam waist (corresponding lengths between converging elements are within twice the Rayleigh range). Our desigr.s u...