scholarly journals Study on the Variations of Image Density Index of MDCT for Healthy Lungs

Author(s):  
Cha Won-Bin ◽  
Yun Sok-Chan ◽  
Ri Chan-Ung ◽  
Chang Chol-Ho
Keyword(s):  
1992 ◽  
Author(s):  
Mary Louise Edwards
Keyword(s):  

1981 ◽  
Vol 45 (03) ◽  
pp. 208-210 ◽  
Author(s):  
D Green ◽  
S M Spies ◽  
N A Rana ◽  
J W Milgram ◽  
R Mintzer

SummaryThe technique of blood pool scanning was used to examine 15 hemophilic subjects. Employing an in vivo method for erythrocyte labeling with Technetium-99 m, a dynamic perfusion sequence is obtained using a scintillation camera positioned over the area to be examined. This demonstrates the vascularity of the tissue. Subsequently, equilibrium blood pool images of the area are obtained and analyzed with a densitometer to assess relative regional blood volume. In patients who were not bleeding but had chronic arthropathy, vascularity was not increased, and the blood volume of comparable joints was similar. By contrast, marked increases in vascularity and image density were observed in studies of acutely bleeding joints. Chronic hemarthroses were associated with persistent, but less marked increases in joint perfusion. Transient increases in joint vascularity were demonstrated after insertion of knee prostheses. In a patient with a thigh hematoma, the dimensions of the hemorrhage were clearly delineated. Since only a tracer dose of nuclide is infused intravenously, there are no allergic reactions or other side effects of the procedure. Blood pool scanning is a safe, non-invasive technique that augments clinical and radiographic evaluations, and provides a new dimension in the assessment of the hemophilic patient.


1997 ◽  
Vol 84 (1) ◽  
pp. 176-178
Author(s):  
Frank O'Brien

The author's population density index ( PDI) model is extended to three-dimensional distributions. A derived formula is presented that allows for the calculation of the lower and upper bounds of density in three-dimensional space for any finite lattice.


1988 ◽  
Vol 61 (728) ◽  
pp. 697-699
Author(s):  
M. G. Samarasekara ◽  
F. R. Hudson

2021 ◽  
pp. 1-17
Author(s):  
Partha Haldar ◽  
Alok Mukherjee ◽  
Tapas Kumar Bhattacharya ◽  
Nipu Modak

Abstract The present research is emphasized on the microscopic observation of post wear surface of nano TiO2 doped alumina ceramics to accesses wearing by promising image processing algorithms viz. entropy analysis, Sobel edge detection technique and entropy filtered image histogram analysis in relation to the extent of doping. The experimental results of specific wear rate showed an indicator with the extent of micro fracturing of grains, ploughing of materials and debris formation on the wear track after a long wear cycles in terms of entropy level, edge density index, entropy filtered image and the nature of histogram at different doping level. The lowest value of entropy level and edge density index is shown at the level of 1 wt.% TiO2 doped alumina ceramics due to the presence of low number of granularity and microfracture grains on the wear track causes the lowering of specific wear rate. The histogram of entropy filtered image for 1 wt.% doping is more uniformly distributed with the highest frequency and lowest skewness factor over a wide range of intensity values for 1 wt.% doping.


2016 ◽  
Vol 40 (5) ◽  
pp. 921-929 ◽  
Author(s):  
Ernani Lopes Possato ◽  
Natalino Calegario ◽  
Gilciano Saraiva Nogueira ◽  
Elliezer de Almeida Melo ◽  
Joyce de Almeida Alves

ABSTRACT The Reineke stand density index (SDI) was created on 1933 and remains as target of researches due to its importance on helping decision making regarding the management of population density. Part of such works is focused on the manner by which plots were selected and methods for the fit of Reineke model parameters in order to improve the definition of SDI value for the genetic material evaluated. The present study aimed to estimate the SDI value for Eucalyptus urophylla using the Reineke model fitted by the method of linear regression (LR) and stochastic frontier analysis (SFA). The database containing pairs of data number of stems per hectare (N) and mean quadratic diameter (Dq) was selected in three intensities, containing the 8, 30 and 43 plots of greatest density, and models were fitted by LR and SFA on each selected intensities. The intensity of data selection altered slightly the estimates of parameters and SDI when comparing the fits of each method. On the other hand, the adjust method influenced the mean estimated values of slope and SDI, which corresponded to -1.863 and 740 for LR and -1.582 and 810 for SFA.


Author(s):  
Juan Carlos Robles ◽  
Mario Fernandez Arce

In this paper we examine the characteristic and distribution of natural and man-made hazards in the District La Fortuna, Costa Rica, and show a Hazards Density Map. There are deadly hazards in the territory and both vulnerability and risk have increased, which demands actions to prevent disasters. Our interest is to provide useful results to improve the risk management in the district. We collected information available in scientific papers, technical reports, thesis, and Press releases and used the method Hazard Density Index to produce the Hazard Density Map. The findings point to a concentration of threats in in North of the district and confirm that the main hazard in the studied area is the volcanic eruption.


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