نتایج جستجو برای: phantoms imaging

تعداد نتایج: 458214  

Introduction: Quality assurance in Computed tomography (CT) centers in developing countries are largely hindered by the unavailability of CT phantoms. The development of a local CT phantom for the measurement of organ radiation absorbed dose is therefore requisite. Material and Methods: Local CT phantoms were designed to meet the standard criteria of 32 cm diameter for body, 16 cm diameter for...

2015
Parisa Akhlaghi Hashem Miri-Hakimabad Laleh Rafat-Motavalli

In order to establish an organ and effective dose database for Iranian children undergoing computed tomography (CT) examinations, in the first step, two Iranian 11-year-old phantoms were constructed from image series obtained from CT and magnetic resonance imaging (MRI). Organ and effective doses for these phantoms were calculated for head, chest, abdomen-pelvis and chest-abdomen-pelvis (CAP) s...

2014
YI-SHAN TSAI JIANG-SHIUH CHEN CHIEN-KUO WANG CHIA-HSING LU CHAO-NENG CHENG CHIN-SHUN KUO YI-SHENG LIU HONG-MING TSAI

The aim of the present study was to determine the correlation between dual-energy computed tomography (DECT) Hounsfield units (HU) and iron concentration, as well as the correlation between HU and magnetic resonance imaging (MRI)-derived R2* values, in phantoms of the heart and liver tissue. Phantoms were constructed containing pig heart or liver tissue and varying concentrations of iron (0.1, ...

2016
Anna Kelaranta

Organ dose is the absorbed radiation energy from ionizing radiation to an organ, divided by the organ mass. Organ doses of a patient cannot be measured directly in the patient, but their determination requires dose measurements in anthropomorphic patient models i.e. phantoms or Monte Carlo simulations. Monte Carlo simulations can be performed for example by using computational phantoms or patie...

Journal: :AJNR. American journal of neuroradiology 1997
E R Melhem H Jara H Shakir T A Gagliano

PURPOSE To evaluate the effect of the hybrid RARE (rapid acquisition with relaxation enhancement) readout, commonly coupled to inversion-recovery pulse sequences, on the null inversiton time (TI) of fluid and fat using both phantoms and human volunteers. METHODS Two phantoms, simulating fat (phantom A) and cerebrospinal fluid (phantom B), respectively, were imaged using a fast inversion-recov...

2017
Muizz A. Wahid Ella Choi David S. MacDonald Nancy L. Ford

The aim of this study is to measure the radiographic dose in adult, adolescent, and child head-sized PMMA phantoms for three panoramic-imaging devices: the panoramic mode on two CBCT machines (Carestream 9300 and i-CAT NG) and the Planmeca ProMax 2D. A SEDENTEXCT dose index adult phantom and custom-built adolescent and pediatric PMMA dosimetry phantoms were used. Panoramic radiographs were perf...

2012
Ronald X. Xu David W. Allen Jiwei Huang Surya Gnyawali James Melvin Haytham Elgharably Gayle Gordillo Kun Huang Valerie Bergdall Maritoni Litorja Joseph P. Rice Jeeseong Hwang Chandan K. Sen

Hyperspectral imaging has the potential to achieve high spatial resolution and high functional sensitivity for non-invasive assessment of tissue oxygenation. However, clinical acceptance of hyperspectral imaging in ischemic wound assessment is hampered by its poor reproducibility, low accuracy, and misinterpreted biology. These limitations are partially caused by the lack of a traceable calibra...

2011
Jason R. Cook Richard R. Bouchard Stanislav Y. Emelianov

In both photoacoustic (PA) and ultrasonic (US) imaging, overall image quality is influenced by the optical and acoustical properties of the medium. Consequently, with the increased use of combined PA and US (PAUS) imaging in preclinical and clinical applications, the ability to provide phantoms that are capable of mimicking desired properties of soft tissues is critical. To this end, gelatin-ba...

Journal: :Biomedical optics express 2014
Marjan Razani Timothy W H Luk Adrian Mariampillai Peter Siegler Tim-Rasmus Kiehl Michael C Kolios Victor X D Yang

In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) in an inhomogeneous phantom and carotid artery samples based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs duration, applying acoustic radiation force (ARF) to inh...

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