نتایج جستجو برای: phantom ct ct number
تعداد نتایج: 1305532 فیلتر نتایج به سال:
BACKGROUND Radiation exposure has been a hot point in research field of computed tomography (CT). Recently, automated tube current modulation (ATCM) has emerged as an important technique to reduce radiation exposure. Many studies have shown that the difference in scout view would affect modulation. This prospective randomized controlled study is aimed to investigate the impact of an additional ...
CT assessment of postoperative spine is challenging in the presence of metal streak artifacts that could deteriorate the quality of CT images. In this paper, we studied the influence of different acquisition parameters on the magnitude of metal streaking. A water-bath phantom was constructed with metal insertion similar with postoperative spine assessment. The phantom was scanned with different...
BACKGROUND Tumor-Treating Fields (TTFields) are a novel treatment strategy for glioblastoma (GBM) that is approved for the use concomitantly to adjuvant chemotherapy. Preclinical data suggest a synergistic interaction of TTFields and radiotherapy (RT). However, the dosimetric uncertainties caused by the highly dense arrays have led to caution of applying the TTF setup during RT. METHODS In a ...
BACKGROUND We evaluated the accuracy and repeatability of a 3D method for polyethylene acetabular cup wear measurements using computed tomography (CT). We propose that the method be used for clinical in vivo assessment of wear in acetabular cups. MATERIAL AND METHODS Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip sim...
Background & Objectives: Computed tomography (CT) represents 11% of all diagnostic radiology procedures but it contributes to almost 67% of the total effective dose to the human population. In head and neck CT which consist of 1/3 of total CT scans, other critical organs such as lenses and thyroid are in the radiation field. Also in the abdomen and pelvis scan, irradiation of ovaries is unavoid...
A whole-body PET/CT scan extending from the vertex of the head to the toes of the patient is not feasible on a number of commercially available PET/CT scanners due to a limitation in the extent of bed travel on these systems. In such cases, the PET scan has to be divided into two parts: one covering the upper body segment, while the other covering the lower body segment. The aim of this paper i...
PURPOSE 1. Comparison and verification of accuracy of the implant reconstruction method based on images from IBU and CT. 2. Estimation of influence of the implant reconstruction method on dose disposition in selected reference points. MATERIAL AND METHODS Paraffin-wax phantom with three catheters, central marker and control point were prepared. IBU unit were used for obtaining two series of i...
OBJECTIVE To assess effects of off-centering, automatic exposure control, and padding on attenuation values, noise, and radiation dose when using in-plane bismuth-based shields for CT scanning. MATERIALS AND METHODS A 30 cm anthropomorphic chest phantom was scanned on a 64-multidetector CT, with the center of the phantom aligned to the gantry isocenter. Scanning was repeated after placing a b...
Background: Medical X-rays are the largest man-made source of public exposure to ionizing radiation. While the benefits of Computed Tomography (CT) are well known in accurate diagnosis, those benefits are not risk-free. CT is a device with higher patient dose in comparison with other conventional radiation procedures. Objective: This study is aimed at evaluating radiation dose to patients from ...
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