نتایج جستجو برای: depth dose
تعداد نتایج: 468234 فیلتر نتایج به سال:
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...
Feasibility Studies on the In-vivo Experiments at the Mc-50 Cyclotron Using a Prototype Lept System*
A prototype LEPT (Low Energy Proton Therapy) system was developed and installed at the MC-50 cyclotron in 2007. Some of the users of the PEFP (Proton Engineering Frontier Project) have been requiring an invivo irradiation system for the utilization in the fields of medical and biological sciences [1]. We are studying on the possibility of in-vivo experiments by using the prototype LEPT system. ...
The inverse problem formulation of the depth dose curve estimation is applied to sparse non-equally spaced measurement grid and the subsequent solution as well as the selection of measurement depths are discussed. The performance of the proposed estimation method is evaluated with real 6 MeV and 18 MeV photon data. These studies show that the proposed method allows the estimation of the depth d...
PRESAGE is a radiochromic solid dosimeter which shows promising potential for 3D proton beam dosimetry. Since an idea dosimeter should be water-equivalent, total depth dose distributions in two PRESAGE formulations irradiated by a 62 MeV proton beam were compared with that in water using GEANT4 Monte Carlo simulations. The dose delivered by secondary particles was also calculated. Our results s...
The purpose of this study was to evaluate a methodology to reduce scatter and leakage radiations to patients' surface and shallow depths during conventional and advanced external beam radiotherapy. Superflab boluses of different thicknesses were placed on top of a stack of solid water phantoms, and the bolus effect on surface and shallow depth doses for both open and intensity-modulated radioth...
Introduction: Monte Carlo method is often applied in radiation therapy as utilized in all the branches of science. An important requirement for successful radiotherapy is carefully examine the dose distribution specifications and decrease the difference between these features with experience to an acceptable level. In this study, the characteristics of 6, 15 and 20 MeV incident x-rays are prov...
Out-of-field dose depends on multiple factors, making peripheral dosimetry com-plex. Only a few dosimeters have the required features for measuring peripheral dose. Plastic scintillator dosimeters (PSDs) offer numerous dosimetric advantages as required for out-of-field dosimetry. The purpose of this study is to determine the potential of using PSD as a surface peripheral dosimeter. Measurements...
Two Monte Carlo systems, EGSnrc and Geant4, were used to calculate dose distributions in large electron fields used in radiotherapy. Source and geometry parameters were adjusted to match calculated results with measurement. Both codes were capable of accurately reproducing the measured dose distributions of the 6 electron beams available on the accelerator. Depth penetration was matched to 0.1 ...
Background: The aim of present study was to analyze the effectiveness of electron filters in the Telecobalt radiotherapy treatment by simulation technique. Materials and Methods: The BEAMnrc Monte Carlo code was used to simulate the electron filters of thickness of 0.5 gm/cm2 below the trimmer bar for 35 × 35 cm2 field size in Theratron Equinox-80 telecobalt unit. The electron filters were mad...
Several studies have been done with the aim of improving the quality of the radiation protection measurement in radiology and nuclear medicine. Among different subjects which are capable to be considered in this area, the measurement of the operational quantities of protection against the radiation ,such as, personal dose equivalent ,HP(d), at different depths (d=0.07mm, 3mm, 10mm) is an impor...
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