نتایج جستجو برای: computed tomography iterativeimage reconstruction

تعداد نتایج: 377600  

2013
Sang Min Yoon Gang-Joon Yoon

Computed tomography (CT) is a popular type of medical imaging that generates images of the internal structure of an object based on projection scans of the object from several angles. There are numerous methods to reconstruct the original shape of the target object from scans, but they are still dependent on the number of angles and iterations. To overcome the drawbacks of iterative reconstruct...

1997
Ariel Rischal Susan S. Young Mehrdad Soumekh

This paper presents a method for volumetric reconstruction from Helical Computerized Tomography (H-CT) data which are collected with a fan beam source. An interpretation of the HCT data in terms of the Axial Computerized Tomography (ACT) data is provided. This analysis indicates that the H-CT data for positive and negative detector angles can be combined to form periodically nonuniform hexagona...

Journal: :iranian journal of radiation research 0
a. saravanakumar department of applied science, psg college of technology, coimbatore 641 004, india k. vaideki 1department of applied science, psg college of technology, coimbatore 641 004, india k.n. govindarajan department of radiology, psg institute of medical science and research & hospitals, coimbatore 641004, india b. devanand department of radiology, psg institute of medical science and research & hospitals, coimbatore 641004, india s. jayakumar department of physics, psg institute of technology and applied research, coimbatore 641 062, india s.d. sharma radiological physics and advisory division, bhabha atomic research centre, mumbai- 400094, india

background: to suggest south india ct diagnostic reference levels (drls) by collecting radiation doses for the most commonly performed ct examinations. materials and methods: a pilot study investigated the most frequent ct examinations. 110 ct sites were asked to complete a survey booklet to allow the recording of ct parameters for each of 3 ct examinations during a 1 year time period. dose dat...

2014
Chul Ho Jang Hyung Chae Yang Tae Ho Um Yong Beom Cho

We report a rare case where Q-tip induced mixed hearing loss without perilymph fistula and demonstrate the need for computed tomography imaging with three-dimensional reconstruction where fracture and dislocation of the stapes are suspected. A 28-year-old male experienced an accidental penetrating injury by a Q-tip in the right ear 6 years previously. Temporal bone computed tomography revealed ...

Introduction: Recent studies of Computed Tomography (CT) conducted on patient dose reduction have recommended using an iterative reconstruction algorithm and mA (mili-Ampere) dose modulation. The current study aimed to evaluate Iterative Dose Reduction Algorithm (IDREAM) as an iterative reconstruction algorithm. Material and Methods: Two CT p...

2007
V. Masilamani C. Vanniarajan Kamala Krithivasan

As the Computed Tomography(CT) requires normally hundreds of projections to reconstruct the image, patients are exposed to more X-ray energy, which may cause side effects such as cancer. Even when the variability of the particles in the object is very less, Computed Tomography requires many projections for good quality reconstruction. In this paper, less variability of the particles in an objec...

Journal: :Radiation protection dosimetry 2016
Marie-Louise Aurumskjöld Kristina Ydström Anders Tingberg Marcus Söderberg

Computed tomography (CT) is one of the most important modalities in a radiological department. This technique not only produces images that enable radiological reports with high diagnostic confidence, but it may also provide an elevated radiation dose to the patient. The radiation dose can be reduced by using advanced image reconstruction algorithms. This study was performed on a Brilliance iCT...

2017
Navdeep R Sayal Ryan J Brisson Kenneth Richey Christine Lepoudre

A 57-year-old man presented with persistent hyperparathyroidism following primary parathyroidectomy. A four-dimensional computed tomography scan with three-dimensional reconstruction showed two parathyroid glands (one right and one left) and anatomic variation from previous surgery. Revision surgery was performed revealing the parathyroid glands as expected from the preoperative three-dimension...

2005
Marshall W. Bern Jindong Chen Hao Chi Wong

In single-particle reconstruction, a 3D structure is reconstructed from a large number of randomly oriented 2D projections, using techniques related to computed tomography. Unlike in computed tomography, however, the orientations of the projections must be estimated at the same time as the 3D structure, and hence the reconstruction process can be error-prone, converging to an incorrect local op...

Osteochondroma is an osseous protuberance with cartilaginous growth potential that usually forms at the ends of long bones such as knee, hip, shoulder and joints(1). Osteochondromas are one of the most common benign tumours of bone, approximately 35% to 50% of all benign tumors and 8% to 15% of all primary bone tumors (2). Only about 1% of these occur within the head and neck region (1). The mo...

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