نتایج جستجو برای: attenuation correctionmlemscatter correctionspect

تعداد نتایج: 48983  

Journal: :archives of razi institute 2016
r. hashemi-fesharki1 s. bozorgi k. esmaeil nia1 g.r. habibi n. bordbar

the sporozoites of theileria annulata invade bovine mhc ii cells, where they differentiate into schizonts. the later can immortalize and induce fundamental changes in their host cells. live attenuated vaccine is an important way of controlling t. annulata infection of cattle. production is by prolonged cultivation of macroschizont-infected cells. the mechanisms underlying this transformation ar...

Journal: :iranian journal of medical physics 0
rezvan khaldari medical physics department, medical school, tabriz university of medical sciences, tabriz, iran asghar mesbahi medical physics department, medical school, tabriz university of medical sciences, tabriz, iran. umit kara suleyman demirel university

introduction: globally, the need for radiotherapy as a part of cancer management increases every year. thus, the shielding for megavoltage radiotherapy rooms is of great importance. materials and methods: in the present study, 14 types of developed high-density concrete with densities ranging from 2.45 to 5.11 were simulated by using monte carlo method. the linear attenuation coefficient and th...

Journal: :iranian journal of nuclear medicine 2007
dariyush shahbazi-gahrouei zahra shahi kourosh ziaie ehsan khodamoradi

introduction:  the use of radioactive iodine (131i) has become an important adjunct to the treatment of thyroid cancer and hyperthyroidism. salivary gland has the ability to concentrate radioactive iodine under normal circumstances. salivary gland dysfunction and dry mouth are the common side effectsof high-dose radioiodine therapy. the purposeof this study was to determine the absorbed dose of...

H. A. Aziz L. Mohajeri, M. A. Zahed M. H. Isa S. Mohajeri

Bioremediation, the process by which microorganisms degrade organic compounds to non-toxic or less toxic substances, has been widely used for cleanup of coastal ecosystems after oil spills. In this study, the hydrocarbon degradation rate and half lives in three bioremediation strategies (natural attenuation, biostimulation, and bioaugmentation) were compared in weathered crude oil (WCO) contami...

A. Amiri, F. Rahmani, M. Baradaran-Ghahfarokhi, M.A. Mosleh Shirazi, S. Jarideh, S.M.J. Mortazavi, S.M.R. Aghamiri,

Background: High density concrete is extensively used for efficient radiation attenuation in radiotherapy rooms and nuclear reactors. Over the past eight years, some efficient galena-based concrete samples for shielding X or gamma rays was produced. The goal of this study was to produce a novel high density concrete against neutron and photon radiations using tourmaline and galena. Materials an...

H. Baharvand, M. Kardan, N. Sharafi, S. Sina, S.M.J. Mortazavi,

Background: Polyethylene composites including boron can be used as an effective neutron shield. Our investigation focuses on manufacturing borated polyethylene nano-composite. The purpose of this study is to design a radiation shield for use in both neutron and gamma fields. Materials and Methods: Borated polyethylene shields containing 2%, and 5% weight percentage of Boron nano-particles w...

Journal: :Journal of nuclear medicine : official publication, Society of Nuclear Medicine 2003
Chuanyong Bai Paul E Kinahan David Brasse Claude Comtat David W Townsend Carolyn C Meltzer Victor Villemagne Martin Charron Michel Defrise

UNLABELLED There has been considerable debate about the desirability of attenuation correction in whole-body PET oncology imaging. The advantages of attenuation correction are quantitative accuracy, whereas the perceived disadvantages are loss of contrast, noise amplification, and increased scanning time. In this work, we explain contrast changes between images reconstructed with and without at...

H. Canakci, I. Akkurt,

Background: Radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. Materials and Methods: The measurement has been performed using gamma spectrometer contains NaI (Tl) detector at the photon energies of 662, 1173 an...

2015
J. S Ojo M. O Ajewole S. K Sarkar

Rain attenuation is a major shortcoming of microwave transmission. J.S Ojo1, 2, M.O Ajewole1, S.K Sarkar2. An improved approach of predicting rain attenuation cumulative. rain attenuation formula Approach for determining the values of rain attenuation at different.Attenuation due to rain is an important constraint in the designing of the microwave. The paper presents a new prediction model of r...

Journal: :The Journal of the Acoustical Society of America 2006
Timothy A Bigelow William D O'Brien

Estimating the characteristic correlation length of tissue microstructure from the backscattered power spectrum could improve the diagnostic capability of medical ultrasound. Previously, size estimates were obtained after compensating for source focusing, the frequency-dependent attenuation along the propagation path (total attenuation), and the frequency-dependent attenuation in the scattering...

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