نتایج جستجو برای: air correction
تعداد نتایج: 368892 فیلتر نتایج به سال:
Background: In treating patients with radiation, the degree of accuracy for the delivery of tumor dose is recommended to be within ± 5% by ICRU in report 24. The experimental studies have shown that the presence of low-density inhomogeneity in areas such as the lung can lead to a greater than 30% change in the water dose data. Therefore, inhomogeneity corrections should be used in treatment pla...
BACKGROUND The aim of the study is to assess accuracy of activity quantification of 177Lu studies performed according to recommendations provided by the committee on Medical Internal Radiation Dose (MIRD) pamphlets 23 and 26. The performances of two scatter correction and three segmentation methods were compared. Additionally, the accuracy of tomographic and planar methods for determination of ...
Buoyancy artefacts (BAs) are used for the experimental determination of air density. The artefacts used for this comparison were manufactured at the PTB and the KRISS respectively and consist of one hollow cylinder and one bobbin. Mass differences of the PTB and the KRISS BAs in vacuum and in air are measured simultaneously by using the PTB prototype mass comparator. Results of the bilateral co...
An experimental investigation of the thermal performance of the He-Cooled Multi-Jet (HEMJ) modular divertor design developed by the Karlsruhe Research Center (FZK) was previously performed at Georgia Tech using air at Reynolds numbers (Re) spanning those at which the actual He-cooled divertor is to be operated. The electrically heated test section was constructed from a brass alloy with nearly ...
Abstract The cylindrical graphite cavity chambers are used for primary standard of air kerma rate of Co-60 and Cs-137. We measured wall attenuation correction factor (Kat) at several irradiation angles using extrapolation technique because of angular dependence. From these results, it can be seen that it is insufficient technique for evaluation of Kat. The Monte Carlo simulations were also done...
Quantitative MR Imaging and Spectroscopy Group, Research Center for Cellular and Molecular Imaging, Tehran University of Medical Sciences, Tehran, Iran Deriving an accurate attenuation correction map (μ-map) from magnetic resonance (MR) volumes has become an important problem in hybrid PET/MR imaging. Recently, short echo-time (STE) MR imaging technique incorporating fuzzy C-means (FCM) tissue ...
While an increasing number of cities is using 3D geo-information, applications like infrastructure planning and the assessment of environmental impact by noise, wind and air pollution require 3D geo-information over areas covering multiple municipalities. To enable such applications a national 3D landscape model has been produced in the Netherlands by automated fusion of the national 1:10,000 s...
Correction for 'A narrow amide I vibrational band observed by sum frequency generation spectroscopy reveals highly ordered structures of a biofilm protein at the air/water interface' by Zhuguang Wang et al., Chem. Commun., 2016, 52, 2956-2959.
Background: Dose calculation algorithms play a very important role in predicting the explicit dose distribution. We evaluated the percent depth dose (PDD), lateral depth dose profile, and surface dose volume histogram in inhomogeneous media using calculation algorithms and inhomogeneity correction methods. Materials and Methods: The homogeneous and inhomogeneous virtual slab phantoms used in th...
A highly accurate two-color interferometer with automatic correction of the refractive index of air was developed for crustal strain observation. The two-color interferometer, which can measure a geometrical distance of approximately 70 m, with a relative resolution of 2 × 10 −9 , clearly detected a change in strain due to earth tides in spite of optical measurement in air. Moreover, a large st...
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