نتایج جستجو برای: photon migration

تعداد نتایج: 210671  

M. Fani, M. H. Naderi,

In this paper, we study the coherent transport of single photon in a coupled resonator waveguide (CRW) where two threelevel Λ-type atomic ensembles are embedded in two separate cavities. We show that it is possible to control the photon transmission and reflection coefficients by using classical control fields. In particular, we find that the total photon transmission and reflection are achieva...

Introduction: The heavyweight concretes have been widely used for constructing medical or industrial radiation facilities with photon sources. Materials and Methods: In this study, heavy concretes containing galena (PbS) and several borated minerals are proposed as suitable materials against photons. The shielding properties of 21 galena concretes containing seven borated minerals with three m...

2014
Sh Bazrafkan K Kazemi

BACKGROUND Near infrared spectroscopy imaging is one of the new techniques used for investigating structural and functionality of different body tissues. This is done by injecting light into the medium and measuring the photon intensity at the surface of the tissue. METHODS In this paper the different medical applications, various imaging and simulation techniques of NIRS imaging is described...

ژورنال: سنجش و ایمنی پرتو 2020

Radiotherapy using linear accelerators is known as an effective modality for cancer treatment. The photons energy of treatment beams significantly affect the dose distribution. Therefore, it is important to accurately evaluate the photon energy spectra. In this study, MCNPX Monte Carlo code (version 2.6.0) was used to simulate an 18 MV photon beam of a Varian 2100C/D linear accelerator. By matc...

Journal: :Journal of biomedical optics 2012
Fuhong Cai Sailing He

We report a fast perturbation Monte Carlo (PMC) algorithm accelerated by graphics processing units (GPU). The two-step PMC simulation [Opt. Lett. 36, 2095 (2011)] is performed by storing the seeds instead of the photon's trajectory, and thus the requirement in computer random-access memory (RAM) becomes minimal. The two-step PMC is extremely suitable for implementation onto GPU. In a standard s...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1997
J Wu L Perelman R R Dasari M S Feld

We present a multichannel tomographic technique to detect fluorescent objects embedded in thick (6.4 cm) tissue-like turbid media using early-arriving photons. The experiments use picosecond laser pulses and a streak camera with single photon counting capability to provide short time resolution and high signal-to-noise ratio. The tomographic algorithm is based on the Laplace transform of an ana...

Journal: :Chemical reviews 1999
V. A. Apkarian N. Schwentner

III. Sample Preparation and Morphology 1492 IV. Photon-Induced Dissociation 1493 V. Perfect Caging 1494 A. Direct Observation of the Caging Process 1494 B. Stabilization of Fragments and Isomerization 1495 1. OClO 1495 2. ICN 1496 VI. Predissociation 1497 A. Electronic Caging by Solvent Symmetry 1497 B. Differential Solvation 1497 VII. Dissociation through Sudden Cage Exit 1499 A. F(2P) 1500 B....

Journal: :British heart journal 1987
D Bell M Jackson A M Millar J J Nicoll M Connell A L Muir

The uptake of indium-111 labelled neutrophils was examined in 30 patients with acute myocardial infarction by planar imaging and single photon emission computed tomography. The time from venepuncture to reinjection of the autologous labelled neutrophils was less than 2.5 hours and imaging was carried out 24 hours later. Twenty three patients had a positive uptake of neutrophils in the myocardiu...

2016
Sang A Park Young-Min Hyun

Immune cells (leukocytes or white blood cells) move actively and sensitively based on body conditions. Despite their important role as protectors inside the body, it is difficult to directly observe the spatiotemporal momentum of leukocytes. With advances in imaging technology, the introduction of two-photon microscopy has enabled researchers to look deeper inside tissues in a three-dimensional...

Journal: :Philosophical transactions of the Royal Society of London. Series B, Biological sciences 1997
B J Tromberg O Coquoz J B Fishkin T Pham E R Anderson J Butler M Cahn J D Gross V Venugopalan D Pham

A multiwavelength, high bandwidth (1 GHz) frequency-domain photon migration (FDPM) instrument has been developed for quantitative, non-invasive measurements of tissue optical and physiological properties. The instrument produces 300 kHz to 1 GHz photon density waves (PDWs) in optically turbid media using a network analyser, an avalanche photodiode detector and four amplitude-modulated diode las...

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