نتایج جستجو برای: phantom ct ct number
تعداد نتایج: 1305532 فیلتر نتایج به سال:
OBJECTIVE To investigate the accuracy, efficiency and radiation dose of a novel laser navigation system (LNS) compared to those of free-handed punctures on computed tomography (CT). MATERIALS AND METHODS Sixty punctures were performed using a phantom body to compare accuracy, timely effort, and radiation dose of the conventional free-handed procedure to those of the LNS-guided method. An addi...
The visualization of medical images, e.g. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), and the utilization of measurement tools to define distances, areas and volumes are very important to health professionals. The quantitative analysis of spatial relations among structures is useful for medical diagnosis. This work describes a visualization system that provides interactive me...
Lung cancer is an important clinical problem and lung cancer screening may lead to an early diagnosis. CT fluoroscopy-guided lung biopsy is a popular method for obtaining a tissue sample for lung cancer diagnosis. However, the radiation exposure for the physician associated with CT fluoroscopy may limit more widespread adoption of this technique. The use of a robotic needle driver that can hold...
Background: In intensity modulated radiation therapy, cone beam computed tomography (CT) has been used to evaluate patients prior to treatment. This study conducted a comparative evaluation of the image reconstruction ability of the clinically used half-fan bowtie filter and the full-fan bowtie filter. Materals and Methods: A CT simulation marker was inserted inside a human phantom, and the pel...
Proton computed tomography (CT) has been described as a solution for imaging the proton stopping power of patient tissues, therefore reducing the uncertainty of the conversion of x-ray CT images to relative stopping power (RSP) maps and its associated margins. This study aimed to investigate this assertion under the assumption of ideal detection systems. We have developed a Monte Carlo framewor...
Cone-beam CT (CBCT) has shown to be a useful imaging modality for various dentomaxillofacial applications. However, optimization and quality control of dental CBCT devices is hampered due to the lack of an appropriate tool for image quality assessment. To investigate the application of different image quality parameters for CBCT, a prototype polymethyl methacrylate (PMMA) cylindrical phantom wi...
Introduction: International Commission on Radiological Protection introduced three basic principles of radiation protection, namely justification, optimization, and dose limit. Medical exposure has no dose limits, and generally, diagnostic reference levels are used as a tool for optimization of patient protection. Material and Methods: Dosimetry was performed on 20 CT scanners located in 14 cit...
introduction: mandibular fracture is the most common facial bone fracture due to facial trauma. a variety of imagings have been used for diagnosis of mandibular fractures. however, the choice of imaging for diagnosis of mandibular fractures is controversial.present study compares the accuracy of the three most common imaging methods in mandibular fracture diagnosis panoramic radiography, corona...
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