نتایج جستجو برای: Phantom CT CT number
تعداد نتایج: 1305532 فیلتر نتایج به سال:
Introduction: One of the most valuable goals of phantoms, replacing with human goals in the field of research and quality control of diagnostic X-ray systems. There are various algorithms and methods for obtaining Homogeneity and CT number linearity for CT scan device. One of the most famous of these methods, the method is to use a uniform and homogeneous environment to comput...
Introduction: One of the main steps in the optimization process in diagnostic imaging is the quality control of radiology devices. The usual method of CT scan calibration is used of a phantom. The phantom created a certain weakening for the radiation through which it passes. One of the most suitable methods for quantitative analysis of the resolution and contrast in CT scan im...
conclusion we constructed and validated a ct colonography phantom with correct density allowing performance of reproducible experiments. materials and methods we found 15 different phantom designs by literature search and compared their advantages and disadvantages based on their description and images. we tested various materials for density and mechanical properties and constructed a phantom ...
Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid ph...
objective: in this study, we aimed to validate the accuracy of computed tomography-based attenuation correction (ctac) using the bilinear scaling method.methods: the measured attenuation coefficient (μm) was compared to a theoretical attenuation coefficient (μt ) using four different ct scanners and an rmi 467 phantom. the effective energy of the ct beam x-rays was calculated, using the aluminu...
Introduction: The use of a simple tissue analog material in the fabrication of medical computed tomography (CT) imaging phantoms has great potential to help researchers. The purpose of the present study is to develop new gel tissue-equivalent materials and determine whether their CT numbers and relative electron densities vary in CT images obtained by scans at different energie...
Introduction: In radiotherapy treatment planning system (TPS), basic input is the data from computed tomography (CT) scan, which takes into account the effect of inhomogeneities in dose calculations. Measurement of CT numbers may be affected by scanner-specific parameters. Therefore, it is important to verify the effect of different CT scanning protocols on Hounsfield unit (HU) and its impact o...
Objective: In this study, we aimed to validate the accuracy of computed tomography-based attenuation correction (CTAC) using the bilinear scaling method.Methods: The measured attenuation coefficient (μm) was compared to a theoretical attenuation coefficient (μt ) using four different CT scanners and an RMI 467 phantom. The effective energy of the CT beam X-rays was calculated, using the aluminu...
Purpose Four-dimensional computed tomography (CT) images are typically used to quantify the necessary internal target volumes for thoracic and abdominal tumors. However, 4-dimensional CT is typically associated with excessive imaging dose to patients and the situation is exacerbated when using repeat 4-dimensional CT imaging on a weekly or daily basis throughout fractionated therapy. The aim of...
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