AIM The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. BACKGROUND Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. MATERIALS AND METHODS MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources...

The usual fluorescence behavior follows Stokes law, where exciting photons are of higher energy than emitted photons. Anti-Stokes processes usually concern emitted energies in excess of excited energies by only a few kT. These processes include anti-Stokes emission by the thermal bands or by the Raman effect. There are processes, however, in which emission photon energy exceeds excited photon e...

The variation in mass attenuation coefficient μ for total and partial photon interaction processes for three different oxide glasses (65CaO-35Al2O3(OG1) , 20Na2O-80SiO2(OG2), and 20Na2O-5Al2O3-75SiO2 (OG3)), in the incident energy range from 10 keV to 100 GeV has been studied using software package XCOM and the effect of chemical composition on the values of μ is also interpreted graphically. M...

Introduction: The heavyweight concretes have been widely used for constructing medical or industrial radiation facilities with photon sources. Materials and Methods: In this study, heavy concretes containing galena (PbS) and several borated minerals are proposed as suitable materials against photons. The shielding properties of 21 galena concretes containing seven borated minerals with three m...

BACKGROUND AND PURPOSE Photon-counting detectors offer the potential for improved image quality for brain CT but have not yet been evaluated in vivo. The purpose of this study was to compare photon-counting detector CT with conventional energy-integrating detector CT for human brains. MATERIALS AND METHODS Radiation dose-matched energy-integrating detector and photon-counting detector head CT...

background: physical wedges are still widely used as beam modifiers in external beam radiotherapy. however the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. the aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...

Background: Physical wedges are still widely used as beam modifiers in external beam radiotherapy. However the presence of them in the beam trace may cause beam hardening which may not be considered in many treatment planning systems. The aim of this study is to investigate the beam hardening effect generated by physical wedges via different beam quality indexes as photon spectrum, half value l...

Introduction: One of the most effective means for treatment of coronary arteries cramp (CHD) is coronary intravascular Brachiotherapy. In this study, with use of MCNP code, in order to invastigating the score of ditribution of absorbed dose, drope in dose, and simulation mean, radiation doses around iridium_192 radioactive has been done.   Materials and Methods:</str...

Background: Monte Carlo method (MC) has played an important role in design and optimization of medical linacs head and beam modeling. The purpose of this study was to compare photon beam features of two commercial linacs, Varian 21EX and Elekta SL-25 using MCNP4C MC code. Materials and Methods: The 6MV photon beams of Varian 21EX and Elekta Sl-25 linacs were simulated based on manufacturers pro...