We detail the development and implementation of a global ablation model that incorporates a dynamically changing tissue absorption coefficient. Detailed spectroscopic measurements rule out plasma-shielding effects during the laser-tissue interaction and thereby support a photochemical mechanism. The model predicts ablation rate ...
NASA Astrophysics Data System (ADS)
In radiofrequency ablation (RFA), successful therapy requires accurate, image-guided placement of the ablation device in a location selected by a predictive treatment plan. Current planning methods rely on geometric models of ablations that are not sensitive to underlying physical processes in RFA. Implementing ...
PubMed
Energy Citations Database
Ablative heat protection prediction of material response and environmental factors for ground- based
NASA Technical Reports Server (NTRS)
Radiofrequency has established itself as a useful technique for managing cardiac arrhythmias and treating soft tissue tumors. However, despite its pervasive use, many of the biophysical principals needed to fully understand and optimize the radiofrequency ablation technique have not been explored. We have designed a test rig that is useful for studying the heat transfer ...
BACKGROUND: A remote magnetic navigation (MN) system is available for radiofrequency ablation of atrial fibrillation (AF), challenging the conventional manual ablation technique. The myocardial markers were measured to compare the effects of the two types of MN catheters with those of a manual-irrigated catheter in AF ablation. ...
Comparisons of ablation calculations with the charring ablation computer code and ablation test data
( 123 ) I-MIBG and Ablation for Atrial Fibrillation.?Introduction: Excessive sympathetic nervous activity may contribute to atrial fibrillation (AF) recurrences after ablation, but its precise role remains controversial. The goals of this study were to assess the effects of AF on the iodine-123-metaiodobenzylguanidine ((123) I-MIBG) findings and to ...
... A model is presented for the prediction of ablation rates and surface temperatures of laser-hardening materials subjected to high heating rates. ...
DTIC Science & Technology
ObjectivesTo assess whether additional ablation in the right atrium(RA) improves termination rate in long-lasting persistent atrial fibrillation(PsAF).BackgroundProlongation of atrial fibrillation(AF) cycle length(CL) measured from the left atrial appendage predicts favorable outcome during catheter ablation of ...
PubMed Central
Background: ?Studies have shown that the presence of left atrial (LA) fibrosis can be assessed by LA delayed-enhancement cardiac magnetic resonance (LA DE-CMR) and may be predictive of outcome after ablation for atrial fibrillation (AF). We sought to test the hypothesis that the amount of LA fibrosis evaluated by DE-CMR correlates with ...
The influence of cumulative absorbed dose, initial dose rate and mass of the remnant thyroid tissue on outcome of radioiodine treatment was assessed to determine an optimum value of absorbed dose and initial dose rate predictive of successful ablation. In 87 patients with thyroid carcinoma treated with 0.85-9.55 GBq (23-258 mCi) of ...
The structural performance of several candidate ablatives for the uptake section of the Navy's Vertical Launching System is investigated. The uptake is modeled using a fixed-fixed beam-loaded by a uniform pressure. Beam displacement field equations are solved, assuming that the ablatives exhibit bimodular behavior in tension and compression. The candidate ...
... Page 3. 00 04 c THE PREDICTION OF HEAT TRANSFER AND ABLATION IN THE AFT-CLOSURE )FA SOLID PROPELLANT ROCKET MOTOR 11" ...
Title: Measured and predicted ablation-product radiation in the near wake. No Digital Version Available: Go to Tips on Ordering. Author: Stephenson, J. D. ...
NASA Website
... Title : Comparison of Predicted Ablation Material Performance with Firing Results for Two Lockheed Propulsion Company 156 - Inch Solid Rocket ...
Comparison of Ablation Predictions for Carbonaceous Materials. Using CEA and JANAF-Based Species Thermodynamics. Frank S. Milos. NASA Ames Research Center, ...
The current popularity of excimer laser refractive surgery suggests a need for continued research and refinements to further improve clinical outcomes. A fundamental limitation of current clinical systems is the lack of real-time feedback specifically addressing the laser-tissue interactions as directly related to laser ablation rates. This paper reports ...
Atrial fibrillation is a significant public health burden, with clinically, epidemiologically and economically significant repercussions. In the last decade, catheter ablation has provided an improvement in morbidity and quality of life, significantly reducing long-term healthcare costs and avoiding recurrences compared with drug therapy. Despite recent progress in techniques, ...
A novel breathing sphere model was developed in order to make microscopic molecular dynamics simulations tractable for laser ablation. The results of the simulations have allowed us to distinguish between desorption and ablation, predict velocity distributions of ablated particles, predict the ...
Current ablation consensus documents define persistent atrial fibrillation (AF) as AF lasting >1 week to 1 year or AF requiring cardioversion or pharmacologic conversion in <1 week. These 2 persistent AF subgroups may have different clinical characteristics and ablation outcomes. We compared 179 patients whose persistent AF was ...
A wide range of local thermal ablative therapies have been developed in the treatment of non resectable hepatocellular carcinoma (HCC) in the last decade. Laser ablation (LA) and radiofrequency ablation (RFA) are the two most widely used of these. This article provides an up to date overview of the role of laser ...
MMP-2 Predicts the Outcome of AF Ablation.?Introduction: Although catheter ablation can effectively eliminate atrial fibrillation (AF), the progression of atrial remodeling increases the risk of recurrence. AF is associated with inflammation and subsequent myocardial fibrosis. We therefore examined the possibility ...
... and ArF lasers predicted by the treatments are in good agreement with e experimental values. The supports a mechanism for excimer laser ablation ...
BACKGROUND: -The aim of the study was to investigate whether the type of arrhythmia recurrence after ablation of persistent atrial fibrillation (AF) has an impact on the maintenance of sinus rhythm after the repeat ablation procedure. METHODS AND RESULTS: -Included were 78 consecutive patients (82% males, mean age: 61�10 years, mean left atrial diameter: ...
Radiofrequency ablation (RFA) has emerged as a safe and predictable technology for treating certain patients with cancer who otherwise have few treatment options. Nurses need to be familiar with all phases of the RFA procedure to create an optimal environment for patients. This article offers a brief review of the RFA procedure and nurses' responsibilities ...
We present a novel technique to predict the outcome of an RF ablation, including the vascular cooling effect. The main idea is to separate the problem into a patient independent part, which has to be performed only once for every applicator model and generator setting, and a patient dependent part, which can be performed very fast. The ...
Selection of candidates to catheter ablation (CA) of long-lasting persistent atrial fibrillation (AF) is challenging, since success is not guaranteed. In this study, we put forward an automated method for noninvasively evaluating the reduction of the complexity of the AF organization following CA. Complexity is meant as the amount of disorganization observed on the ECG, ...
An improved model for CO{sub 2} laser ablation impulse in polyoxymethylene and similar polymers is presented that describes the transition effects from the onset of vaporization to the plasma regime in a continuous fashion. Several predictions are made for ablation behavior.
Catheter ablation is increasingly used to treat patients with atrial fibrillation (AF). Ablation of ganglionic plexi is often performed to reduce vagal innervation and has been shown to confer a better long-term outcome in terms of AF recurrence. We report a case of a patient having AF ablation with a profound ...
Purpose:The point of interest of this retrospective case review is to study refractive changes caused by the hinged lamellar keratotomy and the refractive outcome after laser ablation in a second step within the scope of laser in situ keratomileusis (LASIK) in patients with penetrating keratoplasty.Methods:Data from eight patients obtained before lamellar ...
The androgen receptor (AR) plays a key role in progression to incurable androgen-ablation resistant prostate cancer (PCA). We have identified three novel AR splice variants lacking the ligand binding domain (designated as AR3, AR4 and AR5) in hormone insensitive PCA cells. AR3, one of the major splice variants expressed in human prostate tissues, is constitutively active and ...
Thermal tissue ablation is an interventional procedure increasingly being used for treatment of diverse medical conditions. Microwave ablation is emerging as an attractive modality for thermal therapy of large soft tissue targets in short periods of time, making it particularly suitable for ablation of hepatic and other tumors. ...
This study evaluated the process of ablation produced by a Ti:Sapphire femtosecond laser under different average powers taking place at the enamel/dentin interface. Based on the geometry of ablated microcavities the effective intensity for ablation was obtained. This study shows the validity for the local effective intensity analysis ...
Atrial Fibrillation (AF) is an increasingly common and costly medical problem.1�3 Given the disappointing efficacy and side effects associated with pharmacological therapy for AF, new treatment options are needed. Over the last decade, advances in our understanding of the mechanisms of AF, coupled with iterative improvements in catheter ablation techniques, have spurred the ...
An efficient computational method for near real-time simulation of thermal ablation of tumors via radio frequencies is proposed. Model simulations of the temperature field in a 3D portion of tissue containing the tumoral mass for different patterns of source heating can be used to design the ablation procedure. The availability of a very efficient ...
In most previous work at NASA Ames Research Center, ablation predictions for carbonaceous materials were obtained using a species thermodynamics database developed by Aerotherm Corporation. This database is derived mostly from the JANAF thermochemical tab...
National Technical Information Service (NTIS)
Introduction After initial treatment, differentiated thyroid cancer (DTC) patients are stratified as low and high risk based on clinical/pathological features. Recently, a risk stratification based on additional clinical data accumulated during follow-up has been proposed. Objective To evaluate the predictive value of delayed risk stratification (DRS) obtained at the time of ...
Predictions of material performance using the Aerotherm ablation computer ...... the ACE Program. The calculations were performed for the area ratios ...
The development of the analytic capability to predict the thermal ablation response of promising low
... The authors wish to acknow!edge the contributions to this program by NASA in releasing the Aerotherm computer predictions and in releasing the ...
... The programs appropriate to charring materials and used in the predictions are: Aerotherm Chemical Equilibrium (ACE) Program* Charring ...
... change of the total coating thickness as a ... Descriptors : *PAINTS, *ANTIFOULING COATINGS, MAINTENANCE, ABLATION, THESES, CORROSION ...
... Accession Number : ADA216625. Title : A Difference Scheme with Autocontrol Artificial Viscosity to Predict Ablated Nosetip Shape. ...
