نتایج جستجو برای: beam ct
تعداد نتایج: 242842 فیلتر نتایج به سال:
مقدمه: آگاهی از رابطه آناتومیکی و پاتولوژیکی بین دندان های خلفی با سینوس ماگزیلاری، برای تشخیص و طرح درمان حیاتی است. هدف از این مطالعه، بررسی همبستگی نتایج رادیوگرافی پانورامیک و cbct درتعیین ارتباط کف سینوس ماگزیلاری با ریشه دندان های خلفی فک بالا است. روش بررسی: از آرشیو کلینیک رادیولوژی فک و صورت سجاد و جراحی فک و صورت دکتر نواب اعظم از سال 89 تا 93، تعداد 55 تصویر پانورامیک که دارای اسکن c...
OBJECTIVE To assess the diagnostic potential of 2 different cone-beam computerized tomography (CT) units and compare this with intraoral digital and conventional film in the detection of chemically created periapical lesions. STUDY DESIGN Periapical lesions were created chemically in 27 intact roots of 23 teeth (6 incisors, 4 canines, 6 premolars, and 7 molars). Cone-beam CT and digital and f...
OBJECTIVE Phantoms with simulating mandibular trabecular bone structure fabricated using micro-stereolithography were applied for a quantitative evaluation of cone-beam computed tomography (CT) images. MATERIALS AND METHODS Phantoms with a three-dimensional lattice, in which a square pillar was set at 0.10, 0.20, 0.30 and 0.40 mm at the edge, spaced at 0.60 mm, were made of an acrylic resin u...
chamber.The concept of CTDI is still the basis for dosimetry at modern CT scanners, although the assessment of CTDI in phantoms has been the subject of much discussion and many revisions were required since its initial definition. A fundamental revision was for example needed when helical CT was introduced and the concept of pitch had to be taken into account. With the introduction of diagnosti...
In this paper, we present a method that uses a combination of experimental and modeled data to assess properties of x-ray beam measured using a small-animal spectral scanner. The spatial properties of the beam profile are characterized by beam profile shape, the angular offset along the rotational axis, and the photon count difference between experimental and modeled data at the central beam ax...
X-ray computed tomography (CT) is a non-destructive, radiographic scanning technique that enables the visualisation of both the internal geometry and the composition of a workpiece; X-ray CT is therefore well suited for non-destructive inspection tasks. Several physical processes reduce the quality of CT images, and therefore influence both qualitative and quantitative analyses made from CT dat...
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 ...
Modern CT and micro-CT scanners are rapidly moving from fan-beam toward cone-beam geometry. Half-scan CT algorithms are advantageous in terms of temporal resolution, and widely used in fan-beam and cone-beam geometry. While existing half-scan algorithms for cone-beam CT are in the Feldkamp framework, in this paper we compensate missing data explicitly in the Grangeat framework, and formulate a ...
Background and Aim: The objective of this study was to measure and compare the tissue absorbed dose in thyroid gland, salivary glands, eye and skin in maxillofacial imaging with panoramic, conventional linear tomography, cone beam computed tomography (CBCT) and computed tomography (CT).Materials and Methods: Thermoluminescent dosimeters (TLD) were implanted in 14 sites of RANDO phantom to measu...
Central granular cell odontogenic tumor) CGCOT) of the jaw is an exceedingly rare benign odontogenic neoplasm with 35 reported cases in the literature. Among these, very few studies have focused on the cone-beam CT features of CGCOT. Here, we report a case of an asymptomatic CGCOT in a 16-year-old girl and focus on the cone-beam CT features. Only 36 cases of this lesion, including this one, hav...
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