introduction: computed tomography (ct) and cone-beam ct (cbct) are valuable diagnostic aids for many clinical applications. this study was designed to compare the gray scale value (gsv) and hounsfield unit (hu) of selected dental materials and various hard tissues using ct or cbct. methods and materials: three samples of all test materials including amalgam (am), composite resin (cr), glass ion...

conclusions ultrasound is recommended as the first choice when fb is located within the superficial soft tissues with no bone around it. in case of penetration of fb into deeper tissues or beneath bone, ct or cbct are recommended. otherwise, considering lower dose, cbct is preferred over ct. we can use mri if the fb is not ferromagnetic. however, ct is the first choice in emergency situations b...

An X-ray diffraction computed tomography data-collection strategy that allows, post experiment, a choice between temporal and spatial resolution is reported. This strategy enables time-resolved studies on comparatively short timescales, or alternatively allows for improved spatial resolution if the system under study, or components within it, appear to be unchanging. The application of the meth...

Background: In general, radiotherapy treatment planning is performed using the virtual bolus. It is necessary to investigate physical bolus in comparison to virtual one. Objectives: In the present study, first, radiological properties of superflab Gel bolus and Paraffin wax bolus was investigated in terms of their relative electron density. Then, dosimetric performance of both the bolus (...

fewer than 15% of lipomas occur in the head and neck. lipomas of the larynx are very rare benign laryngeal tumors (0.6%). to date less than 100 case of laryngeal lipoma have been reported in the literature.clinical manifestation include progressive horseness, dyspnea, and even dysphagia. in the direct exam smooth or pedunculated mass is seen in the larynx and sometimes if tumor is large enough ...

Themathematical principles of computed tomography (CT) were first investigated by J. Radon [28] as early as 1917 and were later extended to complex fields by Kirillov [22]. The first application of tomography was, surprisingly, in radio astronomy [2], and today, it finds usage in diverse fields such as medical imaging, seismology, and underwater acoustic imaging. In medical imaging, CT has had ...

Introduction: The basis of image formation in Computed Tomography (CT) lies in the x-ray linear attenuation coefficient of the scanned material. Compton scattering and photoelectric effect are the dominant interactions of the x-ray photons with the subject, in the range of diagnostic radiology. These two coefficients are important in tissue characterization by Dual-Energy CT (D...

BACKGROUND In computed tomography (CT), the source-detector system commonly rotates around the object in a circular trajectory. Such a trajectory does not allow to exploit a detector fully when scanning elongated objects. OBJECTIVE Increase the spatial resolution of the reconstructed image by optimal zooming during scanning. METHODS A new approach is proposed, in which the full width of the...

Radiation dose in x-ray computed tomography (CT) has become a topic of high interest due to the increasing numbers of CT examinations performed worldwide. This review aims to present an overview of current concepts for both scanner output metrics and for patient dosimetry and will comment on their strengths and weaknesses. Controversial issues such as the appropriateness of the CT dose index (C...