Background: Exposure conditions in CT examinations are quite different from conventional Xray. In CT examination higher dose is given to patient in comparison with the dose in other diagnostic examinations. In order to calculate organ effective dose in chest CT, Monte Carlo simulation has been used in this study. Materials and Methods: The Impact survey data were used to determine the ...

background: dose calculation algorithms play a very important role in predicting the explicit dose distribution. we evaluated the percent depth dose (pdd), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. materials and methods: the homogeneous and inhomogeneous virtual slab phantoms used in th...

Introduction: Intensity modulated radiation therapy (IMRT) and three-dimensional conformal radiation therapy (3D CRT) are two treatment modalities in prostate cancer, which provide acceptable dose distribution in tumor region with sparing the surrounding normal tissues. IMRT is based on inverse planning optimization; in which, intensity of beams is modified by using multileaf c...

introduction:the use of beta emitters is one of the effective methods for palliation of bone metastasis. the risk of normal tissue toxicity should be evaluated in the bone pain palliation treatment. methods: in this study, the monte carlo simulation code mcnpx was used for simulation a bone phantom model consisted of bone marrow, bone and soft tissue. specific absorbed fractions were calculated...

Introduction: Multiple fields and presence of heterogeneities create complex dose distributions that need three dimensional dosimetry. In this work, we investigated MR-based MAGIC gel dosimetry as a three-dimensional dosimetry technique to measure the delivered dose to bladder and rectum in prostate radiation therapy. Materials and Methods: A heterogeneous slab phantom including bones was made....

Introduction: We evaluated a dose comparison tool that can be used to evaluate measured and calculated dose distributions(1). The tool can be used to evaluate dose calculation algorithms by comparison against measurements, or calculations against calculations. The tool is based on a generalization of the dose-difference and distance-to-agreement tools recently described by Harms et al.(2) and i...

Purpose. To assess differences in dose distribution of a vertebral body injected with bone cement as calculated by radiation treatment planning system (RTPS) and actual dose distribution. Methods. We prepared two water-equivalent phantoms with cement, and the other two phantoms without cement. The bulk density of the bone cement was imported into RTPS to reduce error from high CT values. A dose...