نتایج جستجو برای: phantom ct ct number
تعداد نتایج: 1305532 فیلتر نتایج به سال:
Introduction: Noise and spatial resolution (SR) are the main characteristics of image quality in CT scanning affected by different radiation and technical parameters. One of the important parameters are reconstruction kernels. Different reconstruction kernels are used for noise reduction and/or edge-enhancement purposes. In this study, we investigate some reconstruction kern...
Introduction: The image quality of computed tomography (CT) can be seriously lowered by metal implants of patients. These implants are known to exert a significant impact on diagnostic accuracy due to artifacts. The current study aimed to assess the usefulness of Metal Artifact Reduction (MAR) software in the reduction of metal artifacts, in comparison to iterative rec...
PURPOSE A phantom study was conducted to evaluate the feasibility of body contour definition with Compton scatter photons from external sources of technetium-99m pertechnetate (Tc-99m) to create a fusion image of CT and SPECT images. METHODS External sources of 1 mCi (37 MBq) Tc-99m were placed on each collimator, and body-contour SPECT images were obtained with an energy window of 100 keV +/...
background and aims. the imaging techniques commonly used for foreign body detection include plain radiography, xeroradiography, computed tomography (ct) scans, magnetic resonance imaging (mri) and ultrasonography. the aim of the present study was to compare cone-beam computed tomography (cbct) with conventional ct scan in determination of the exact location of a foreign body in the maxillofaci...
the c7-ras 6/061-004 training course by the international atomic energy agency/regional cooperative agreement (iaea/rca) was held in chiba in 2014. the syllabus, pre- and post-course evaluations, and survey questionnaire results were assembled in this course. the post-course evaluation, including 32 questions similar to the pre-course evaluation, was performed right after the end of the final e...
Introduction: There are several techniques for reducing the delivered dose from CT scans such as the automatic exposure control (AEC). This technique regulates the tube current regarding the patient size and weight. The aim of this study was estimation the effective and equivalent dose for radiosensitive organs in women undergoing chest CT scans with or without AEC system using the patient&rsqu...
Introduction: The advent of dual-modality PET/CT scanners has revolutionized clinical oncology by improving lesion localization and facilitating treatment planning for radiotherapy. In addition, the use of CT images for CT-based attenuation correction (CTAC) decreases the overall scanning time and creates a noise-free attenuation map (6map). CTAC methods include scaling, s...
Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab-wooden dust (pine)-SP34 slab (SWS) heterogeneous phantom. Materials and Methods: Th...
In this study, the phantom imaging quality of 64-slice CT acquisition protocol was quantitatively evaluated using Taguchi. The phantom acrylic line group was designed and assembled with multiple layers of solid water plate in order to imitate the adult abdomen, and scanned with Philips brilliance CT in order to simulate a clinical examination. According to the Taguchi L8(2(7)) orthogonal array,...
PURPOSE To develop a realistic yet flexible 4D digital phantom based on patient anatomy for dynamic estimation of organ doses due to external ionizing radiation. METHODS In this work, we propose to build a 4D digital phantom based on patient CT anatomy and time-tagged CT information. A regional 4D-CT is first acquired on the patient around lesion with a RPM system. By binning CT information a...
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