Background: The heterogeneous composition of the human body presents numerous tissue types and cavities with widely differing radiologic properties. The aim of the present work was to develop a low cost homogeneous and heterogeneous phantom and the absorbed dose were measured by ionization chamber for different radiotherapy treatment techniques and compared with treatment planning syst...

PURPOSE A new cone-beam CT scanner for image-guided radiotherapy (IGRT) can independently rotate the source and the detector along circular trajectories. Existing reconstruction algorithms are not suitable for this scanning geometry. The authors propose and evaluate a three-dimensional (3D) filtered-backprojection reconstruction for this situation. METHODS The source and the detector trajecto...

We have investigated the feasibility of using a set of multiple MOSFETs in conjunction with the mobile MOSFET wireless dosimetry system, to perform a comprehensive and efficient quality assurance (QA) of IMRT plans. Anatomy specific MOSFET configurations incorporating 5 MOSFETs have been developed for a specially designed IMRT dosimetry phantom. Kilovoltage cone beam computed tomography (kV CBC...

The appropriate evaluation of measured doses in mixed fi elds requires the calibration of dosimeters in relation to different types of radiation and exposure conditions in order to split the signal into individual components corresponding to the specifi c radiation and exposure conditions of the entire period and evaluate the critical level, lower limit of detection and corresponding uncertaint...

We present an experimental validation of the distorted Born iterative method with two-step shrinkage thresholding (DBIM-TwIST) algorithm for problem brain stroke detection and differentiation, using anatomically accurate, multi-layer head phantom. To this end, we have developed a gelatine-based, complex phantom which mimics various tissues also includes target mimicking hemorrhagic or ischemic ...

  Introduction: Geometric distortion is a major shortcoming of magnetic resonance imaging (MRI), which has an important influence on the accuracy of volumetric measurements, an important parameter in neurology and oncology. Our goal is to design and construct a new three- dimensional phantom using a 3D printer in order to measure geometric distortion and its reproducibility in...

obtaining temperature distribution data of slabs under rolling is essential as the mechanical and metallurgical properties of the metal under this process vary with temperature. using the control volume method, a mathematical model is employed in this study to predict slab temperature in the hot roll process at mobarakeh steel company. the effects of different parameters including the heat resu...

SPECT detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. Attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. In our study efficacy of Chang method was evaluated for attenuation purpose, using a custom made heart phantom. Due to d...

background: the purpose of this study is to fabricate inexpensive in-house low cost homogeneous and heterogeneous human equivalent thorax phantom and assess the dose accuracy of the treatment planning systems (tps) calculated values for different lung treatment dosimetery. it is compared with thermoluminescent dosimeter (tld) measurement. materials and methods: homogeneous and heterogeneous tho...

Introduction: Ultra-short echo time (UTE) imaging has been proposed as a method for visualizing short T2 relaxation components in the head and has demonstrated the ability to visualize structures such as the dura mater, falx cerebri, bone marrow and short T2 white matter compartments [1]. Previous work has demonstrated UTE imaging using 2D radial [1], 2D spiral [2] and 3D stack-of-spiral [3] im...