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Computer Modeling of Factors that Affect the Minimum Safety Distance Required for Radiofrequency Ablation Near Adjacent Nontarget Structures
- Source :
- Journal of Vascular and Interventional Radiology. 19:1079-1086
- Publication Year :
- 2008
- Publisher :
- Elsevier BV, 2008.
-
Abstract
- To use computer modeling of radiofrequency (RF) ablation to evaluate the effects of (i) composition and varying perfusion of intervening tissue and (ii) electrode orientation and type on the required distance to avoid heating damage of adjacent nontarget structures.Systematic three-dimensional finite-element computer simulation of RF heating (6-20 minutes) was performed (3,128 simulations). The distance (5-25 mm) between the electrode and the potentially injured structure and tissue composition as layers of tumor/soft tissue, fat, and/or fluid was varied (thermal conductivity, 0.46, 0.23, and 0.7 W/m- degrees C; electrical conductivity, 0.5, 0.1, and 1 S/m, respectively). Varying perfusion (0-5 kg/m(3)-s), electrode orientation (parallel or perpendicular), and electrode type (ie, noncooled and internally cooled 3-cm single or 2.5-cm cluster) were also studied. The time required to reach various temperatures (eg, the time to reach 50 degrees C designated as t50) and the distances at which the temperatures occurred and the distances required to avoid threshold temperatures at the margin of adjacent structures were compared.In all cases, increasing the amount of intervening fat increased t50 compared with tumor/soft tissue and/or fluid. With no perfusion, 9 mm of fat or 14 mm of tumor/soft tissue or fluid was required for perpendicular insertion (internally cooled single electrode) to prevent a temperature of 50 degrees C with 12 minutes of heating, compared with 12 mm of fat or 23 mm of tumor/soft tissue or fluid for parallel insertion. Less intervening fat was needed for noncooled electrodes (8 mm parallel,5 mm perpendicular), with more intervening tissue required for cluster electrodes (13 mm) for an RF application of 20 minutes. Finally, the amount of intervening tissue required to prevent damage also decreased linearly with increasing perfusion for each tissue and electrode (r(2) = 0.74 for parallel; r(2) = 0.98 for perpendicular).In the computer model described in the present study, thermal and perfusion characteristics between the electrode and adjacent nontarget structures (specifically the presence of fat) and the electrode characteristics themselves (including parallel versus perpendicular insertion) have been shown to affect the minimum safe distance required for the prevention of thermal injury.
- Subjects :
- medicine.medical_specialty
Hot Temperature
Time Factors
Radiofrequency ablation
9 mm caliber
medicine.medical_treatment
Finite Element Analysis
Models, Biological
Risk Assessment
law.invention
Imaging, Three-Dimensional
law
Dielectric heating
Computer Graphics
medicine
Perpendicular
Humans
Computer Simulation
Radiology, Nuclear Medicine and imaging
Electrodes
business.industry
Electric Conductivity
Soft tissue
Equipment Design
Ablation
Surgery
Perfusion
Electrode
Body Composition
Catheter Ablation
Wounds and Injuries
Cardiology and Cardiovascular Medicine
business
Biomedical engineering
Subjects
Details
- ISSN :
- 10510443
- Volume :
- 19
- Database :
- OpenAIRE
- Journal :
- Journal of Vascular and Interventional Radiology
- Accession number :
- edsair.doi.dedup.....cccc7c7b6232815e4b614950131aacfd