نتایج جستجو برای: phantoms imaging

تعداد نتایج: 458214  

Journal: :International journal of health services : planning, administration, evaluation 2007
Patrick Bond

This article synthesizes new data about the outflow of Africa's wealth, to reveal structural factors behind the continent's ongoing underdevelopment. The flow of wealth out of sub-Saharan Africa to the North occurs primarily through exploitative debt and finance, phantom aid, capital flight, unfair trade, and distorted investment. Although the resource drain from Africa dates back many centurie...

Journal: :Magnetic resonance in medicine 2008
William A Grissom Chun-Yu Yip Steven M Wright Jeffrey A Fessler Douglas C Noll

Current methods for parallel excitation RF pulse design are based on the small-tip-angle approximation, which provides a computationally efficient means of pulse calculation. In general, pulses designed with those methods are inaccurate when scaled to produce large-tip angles, and methods for large-tip-angle pulse design are more computationally demanding. This paper introduces a fast iterative...

Journal: :Journal of microscopy 2004
M R Arnison K G Larkin C J R Sheppard N I Smith C J Cogswell

We propose an extension to Nomarski differential interference contrast microscopy that enables isotropic linear phase imaging. The method combines phase shifting, two directions of shear and Fourier-space integration using a modified spiral phase transform. We simulated the method using a phantom object with spatially varying amplitude and phase. Simulated results show good agreement between th...

Journal: :Hellenic journal of nuclear medicine 2013
Masato Kobayashi Hiroshi Wakabayashi Hironori Kojima Takahiro Konishi Koichi Okuda Hiroto Yoneyama Daiki Kayano Minoru Tobisaka Hiroyuki Tsushima Masahisa Onoguchi Keiichi Kawai Seigo Kinuya

Whole-body and single photon emission tomography (SPET) images during sodium iodide-131 (Na131I) ablation are useful to confirm the efficacy of ablation using 131I imaging. However, there have been no attempts to improve the quality of 131I imaging. We therefore investigated imaging protocols for 131I imaging in differentiated thyroid cancer (DTC). Phantoms containing 131I were used to simulate...

Journal: :Physics in medicine and biology 2009
Jonathan Vappou Caroline Maleke Elisa E Konofagou

Quantifying the mechanical properties of soft tissues remains a challenging objective in the field of elasticity imaging. In this work, we propose an ultrasound-based method for quantitatively estimating viscoelastic properties, using the amplitude-modulated harmonic motion imaging (HMI) technique. In HMI, an oscillating acoustic radiation force is generated inside the medium by using focused u...

Journal: :Radiology 2013
Eric R Muir Yi Zhang Oscar San Emeterio Nateras Qi Peng Timothy Q Duong

PURPOSE To develop a magnetic resonance (MR) imaging approach to noninvasively image quantitative Po(2) in the human vitreous. MATERIALS AND METHODS Human studies were approved by the institutional review board with informed consent obtained from all subjects and were HIPAA compliant. Animal studies were performed with animal care committee approval. An MR imaging method to measure the longit...

Journal: :Optics express 2004
Tomasz Tkaczyk Mohammed Rahman Vivian Mack Konstantin Sokolov Jeremy Rogers Rebecca Richards-Kortum Michael Descour

Structured-illumination microscopy delivers confocal-imaging capabilities and may be used for optical sectioning in bio-imaging applications. However, previous structured-illumination implementations are not capable of imaging molecular changes within highly scattering, biological samples in reflectance mode. Here, we present two advances which enable successful structured illumination reflecta...

Journal: :Optics express 2007
Juliette Selb Anders M Dale David A Boas

We present 3D linear reconstructions of time-domain (TD) diffuse optical imaging differential data. We first compute the sensitivity matrix at different delay gates within the diffusion approximation for a homogeneous semi-infinite medium. The matrix is then inverted using spatially varying regularization. The performances of the method and the influence of a number of parameters are evaluated ...

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