The analysis of tissue temperature rise caused by linear array transducers with Program Spheresum

2016 ◽  
Author(s):  
Murat Alparslan Gungor ◽  
Irfan Karagoz
Keyword(s):  
Temperature Rise ◽  
Linear Array ◽  
Tissue Temperature

Radio-Frequency Ablation in a Realistic Reconstructed Hepatic Tissue

2006 ◽  
Vol 129 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Prasanna Hariharan ◽  
Isaac Chang ◽  
Matthew R. Myers ◽  
Rupak K. Banerjee
Keyword(s):  
Temperature Rise ◽  
Cell Damage ◽  
Three Dimensional ◽  
Thermal Response ◽  
Tumor Location ◽  
Tissue Temperature ◽  
Patient Specific ◽  
Hepatic Tissue ◽  
Thermal Dose ◽  
Element Mesh

This study uses a reconstructed vascular geometry to evaluate the thermal response of tissue during a three-dimensional radiofrequency (rf) tumor ablation. MRI images of a sectioned liver tissue containing arterial vessels are processed and converted into a finite-element mesh. A rf heat source in the form of a spherically symmetric Gaussian distribution, fit from a previously computed profile, is employed. Convective cooling within large blood vessels is treated using direct physical modeling of the heat and momentum transfer within the vessel. Calculations of temperature rise and thermal dose are performed for transient rf procedures in cases where the tumor is located at three different locations near the bifurcation point of a reconstructed artery. Results demonstrate a significant dependence of tissue temperature profile on the reconstructed vasculature and the tumor location. Heat convection through the arteries reduced the steady-state temperature rise, relative to the no-flow case, by up to 70% in the targeted volume. Blood flow also reduced the thermal dose value, which quantifies the extent of cell damage, from ∼3600min, for the no-flow condition, to 10min for basal flow (13.8cm∕s). Reduction of thermal dose below the threshold value of 240min indicates ablation procedures that may inadequately elevate the temperature in some regions, thereby permitting possible tumor recursion. These variations are caused by vasculature tortuosity that are patient specific and can be captured only by the reconstruction of the realistic geometry.

Effect of Rate of Blood Flow Through Large Blood Vessels on HIFU Temperature Rise

2008 ◽  
Author(s):  
Subhashish Dasgupta ◽  
Prasanna Hariharan ◽  
Matthew R. Myers ◽  
Rupak K. Banerjee
Keyword(s):  
Blood Flow ◽  
Temperature Rise ◽  
Focused Ultrasound ◽  
Small Region ◽  
High Intensity Focused Ultrasound ◽  
Acoustic Energy ◽  
Tissue Temperature ◽  
Invasive Technique ◽  
Cell Necrosis ◽  
Flow Through

High Intensity Focused Ultrasound (HIFU) shows considerable promise as a minimally-invasive technique for tumor ablation. A typical HIFU procedure involves focusing of acoustic energy in a small region, with the absorbed acoustic energy causing localized rise in tissue temperature. Temperature rise of the order of 40–60°C is achieved within seconds, causing immediate cell necrosis in the targeted region.

Temperature Rise in Tissue Mimicking Material During HIFU Procedures

2007 ◽  
Author(s):  
Subhashish Dasgupta ◽  
Prasanna Hariharan ◽  
Matthew R. Myers ◽  
Rupak K. Banerjee
Keyword(s):  
Temperature Rise ◽  
Focused Ultrasound ◽  
Acoustic Power ◽  
Tumor Ablation ◽  
High Intensity Focused Ultrasound ◽  
Tissue Temperature ◽  
Invasive Technique ◽  
Operational Parameters ◽  
Tissue Mimicking Material

High Intensity Focused Ultrasound (HIFU) has shown considerable promise as a minimally-invasive technique for various therapeutic applications such as tumor ablation and vessel cauterization. The efficacies of these HIFU procedures depend on various operational parameters such as total acoustic power, pulse duration and transducer dimensions. In this study, the effect of total acoustic power on the tissue temperature rise is studied both experimentally and numerically. Experimentally, HIFU ablations, at different acoustic powers, were carried out in a tissue mimicking material embedded with thermocouples. Temperature rise measured from the in-vitro experiments were then validated with the numerical computations. Results show that experimental and numerical temperature rise match accurately. Our numerical model was able to predict the peak temperature rise within ∼12% of the experimental results. Results also show that the tissue temperature rise is linearly proportional to the input acoustic power. For the acoustic power levels considered in this study, the results suggest that acoustic non-linearity does not play a major role on the tumor ablation procedure.

Umatilla Virus Association with Fibrils and Tubules in Cultured Cells

1980 ◽  
Vol 38 ◽  
pp. 476-477
Author(s):  
Neil M. Foster ◽  
Ruth D. Breckon
Keyword(s):  
Bluetongue Virus ◽  
Linear Array ◽  
Cultured Cells ◽  
Intimate Association ◽  
Infected Cells ◽  
Dark Staining ◽  
In Cells

Macrotubules have been described1 in cells infected with Umatilla virus (UMAV), an orbivirus for which bluetongue virus (BTV) is the protype. Macrotubules, often in linear array, were observed in the cytoplasm and in intimate association with viroplasms of infected cells. Macrotubules had outside and inside diameters of 20 and 15 nm and many had dark-staining centers with diameters similar to the interiors of the tubules. UMAV was 60 nm and the RNA core was 30 nm in diameter. This report describes the association of UMAV with macrotubules and two types of microtubules.

The Impact of Temperature Rise and Regional Factors on Malaria Risk

2014 ◽  
Vol 34 (1) ◽  
pp. 436-455 ◽  
Author(s):  
채수미 ◽  
YOONSEOKJUN ◽  
신호성 ◽  
김동진
Keyword(s):  
Temperature Rise ◽  
Malaria Risk ◽  
Regional Factors ◽  
The Impact

A Center-Feed Linear Array of Reflection-Canceling Slot Pairs on Post-Wall Waveguide

2011 ◽  
Vol E94-B (1) ◽  
pp. 326-329 ◽  
Author(s):  
Jae-Ho LEE ◽  
Jiro HIROKAWA ◽  
Makoto ANDO
Keyword(s):  
Linear Array

Stress Analysis of a Tire Under Vertical Load by a Finite Element Method

1977 ◽  
Vol 5 (2) ◽  
pp. 102-118 ◽  
Author(s):  
H. Kaga ◽  
K. Okamoto ◽  
Y. Tozawa
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Computer Program ◽  
Temperature Rise ◽  
Strain Energy ◽  
Internal Stresses ◽  
Vertical Load ◽  
The Finite Element Method ◽  
Internal Temperature ◽  
Element Method

Abstract An analysis by the finite element method and a related computer program is presented for an axisymmetric solid under asymmetric loads. Calculations are carried out on displacements and internal stresses and strains of a radial tire loaded on a road wheel of 600-mm diameter, a road wheel of 1707-mm diameter, and a flat plate. Agreement between calculated and experimental displacements and cord forces is quite satisfactory. The principal shear strain concentrates at the belt edge, and the strain energy increases with decreasing drum diameter. Tire temperature measurements show that the strain energy in the tire is closely related to the internal temperature rise.

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