نتایج جستجو برای: computed tomography phantom

تعداد نتایج: 279342  

Journal: :Revista Brasileira de Física Médica 2022

A proposed method to obtain the dose for Computed Tomography was evaluated on long a phantom, made of polyethylene. This phantom is 600 mm large. Adopting an empirical characterized function , tendency asymptotical grow by increase scanning length can estimate in infinite single axial rotation x-ray tube. The curve estimated different clinical protocols: tension, pitch, head/body, and center/pe...

2015
Yuya Nakamura Seiji Tomiguchi Masayuki Tanaka

BACKGROUND Generally, attenuation correction is made by incorporating a linear attenuation coefficient, which is based on the attenuation coefficient map (mu-map) created from a computed tomography scan, into the ordered subsets-expectation maximization reconstruction method in non-uniform domains. A non-uniform Chang's attenuation correction method that uses the mu-map created from a computed ...

Journal: :Journal of X-ray science and technology 2015
Guohe Wang Bin Zhang Yichen Ding Yun He Jingsong Chen Yanye Lu Xiaoyun Jiang Junwei Shi Jing Bai Qiushi Ren Changhui Li

Nowadays multi-modality imaging has gained great interest in biology research by offering complementary information. In this paper, a modularly designed fluorescence molecular tomography (FMT) system has been developed, which can be not only used as a standalone imaging device, but also feasibly integrated with other imaging modalities, such as X-ray computed tomography (X-CT), single photon em...

2016
Yannick Poirier Mauro Tambasco

We present an experimental validation of a kilovoltage (kV) X-ray source characterization model in an anthropomorphic phantom to estimate patient-specific absorbed dose from kV cone-beam computed tomography (CBCT) imaging procedures and compare these doses to nominal weighted CT-dose index (CTDIw) dose estimates. We simulated the default Varian on-board imager 1.4 (OBI) default CBCT imaging pro...

Introduction: The present study is aimed to design and develop a tissue-equivalent pelvic phantom, mimicking the Indian female pelvic dimensions by means of locally available and cost-effective tissue substitutes having equivalent radiological properties. Materials and Methods: For the purpose of the study, the real female pelvic bones were embedded for preparation. Paraffin wax, Aloe-vera powd...

Introduction: Geometric distortion, an important parameter in neurology and oncology. The current study aimed to design and construct a new three-dimensional (3D) phantom using a 3D printer in order to measure geometric distortion and its 3D reproducibility. Material and Methods: In this study, a new phantom ...

Abdolazim Sedighi Fahimeh Rezaei, Mohammad Hadi Gholami Mohammad Mohammadi, Ramin Jaberi

Introduction: A study was performed to evaluate radiation dose distribution and dose gradient around cylindrical applicators for high-dose-rate (HDR) brachytherapy systems with 192Ir, 60Co brachytherapy source applied for rectal and vaginal cancers treatments.   Materials and Methods: Two additional computed tomography (CT) based plans were generated using a ...

A Mesbahi, Ü Kara M Johari, N Gharehaghaji, R Ghanbarnezhad Farshi

Background: While the benefits of cone-beam computed tomography (CBCT) are well known in maxillofacial imaging, the use of this modality is not risk-free.Objective: The aim of this study was to evaluate the exposure doses received by patients during maxillofacial imaging with CBCT.Methods: Entrance surface dose (ESD) was measured by using thermoluminescent dosimeters (TLDs) attached to the eyes...

Journal: :Oral surgery, oral medicine, oral pathology and oral radiology 2014
Gerald R Torgersen Caroline Hol Anne Møystad Kristina Hellén-Halme Mats Nilsson

OBJECTIVE The purpose of this work was to develop an inexpensive phantom for simplified image quality assurance (IQA) together with algorithms for objective evaluation of image quality parameters and to integrate these components into an easy-to-use software package. This should help make quality control of dental cone beam computed tomography (CBCT) units accessible, easy, and affordable for a...

2007
George Starkschall Neil Desai Peter Balter Karl Prado Dershan Luo Dianna Cody Tinsu Pan

The purpose of the present work was to describe the development and validation of a series of tests to assess the quality of four-dimensional (4D) computed-tomography (CT) imaging as it is applied to radiation treatment planning. Using a commercial respiratory motion phantom and a programmable moving platform with a CT phantom, we acquired 4D CT datasets on two commercial multislice helical CT ...

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