background: two protocols of aapm tg-51 and iaea trs-398 were compared followed by a measurement and monte carlo simulation of beam quality correction factor, kq, aapm tg-51 and iaea trs-398 protocols were compared for the absorbed dose to water for dw, and kq parameters. materials and methods: dose measurements by either protocols were performed with cylindrical and plane parallel chambers for...

the hydration of biomolecules is vitally important in molecular biology, so in this paper thesolvation energy and radial distribution function of dna bases have been calculated by themonte carlo simulation.the geometries of isolated adenine, guanine, cytosine, and thyminehave been optimized using 6-31+g(d,p) basis function sets. these geometries then will be used inthe monte carlo calculation o...

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...

introduction: scattered photon is one of the main defects that degrade the quality and quantitative accuracy of nuclear medicine images. accurate estimation of scatter in projection data of spect is computationally extremely demanding for activity distribution in uniform and non-uniform dense media. methods: the objective of this paper is to develop and validate a scatter correction technique ...

background: obtaining high quality images in single photon emission tomography (spect) device  is the most important goal in nuclear medicine. because if image quality is low, the possibility of making a mistake in diagnosing and treating the patient will rise. studying effective factors in spatial resolution of imaging systems is thus deemed to be vital. one of the most important factors in sp...

introduction: in single photon emission computed tomography (spect), the projection data used for image reconstruction are distorted by several factors, including attenuation and scattering of gamma rays, collimator structure, data acquisition method, organ motion, and washout of radiopharmaceuticals. all these make reconstruction of a quantitative spect image very difficult. simulation of a sp...

introduction use of hadron therapy as an advanced radiotherapy technique is increasing. in this method, secondary particles are produced through primary beam interactions with the beam-transport system and the patient’s body. in this study, monte carlo simulations were employed to determine the dose of produced secondary particles, particularly neutrons during treatment. materials and methods i...

the monte carlo method can be used to describe any technique that approximates solutions to quantitative problems through statistical sampling. this method is considered to be the most accurate method for dose calculation in radiotherapy. for complete modeling of a linear accelerator, it is required that the manufactured information covers all data, but some data such as primary electron energy...

introduction accurate estimation of the skin-absorbed dose in external radiation therapy is essential to estimating the probability of secondary carcinogenesis induction materials and methods electron contamination in prostate radiotherapy was investigated using the monte carlo (mc) code calculation. in addition, field size dependence of the skin dose was assessed. excess cancer risk induced by...