A hydrophobic gel phantom for study of thermochemical ablation: initial results using a weak acid and weak base
| Autor: | John C. Bischof, Erik N.K. Cressman, Andrew Misselt, Theresa L. Edelman, Jeung H. Choi |
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| Rok vydání: | 2008 |
| Předmět: |
Exothermic reaction
Ablation Techniques Chromatography business.industry Hyperthermia Induced Hydrogen-Ion Concentration Chemical reaction chemistry.chemical_compound Acetic acid Ammonium hydroxide chemistry pH indicator Materials Testing Medicine Radiology Nuclear Medicine and imaging Chemical stability Cardiology and Cardiovascular Medicine business Mineral oil Weak base Gels Hydrophobic and Hydrophilic Interactions medicine.drug |
| Zdroj: | Journal of vascular and interventional radiology : JVIR. 20(10) |
| ISSN: | 1535-7732 |
| Popis: | Purpose To develop a model for study of exothermic chemical reactions potentially useful for tissue ablation. Materials and Methods Seven gelatins ranging from 0.5% to 30% wt/vol with and without 15% or 30% caps and several commercial gels were evaluated. Baseline temperature measurements were taken. Acetic acid and ammonium hydroxide were sequentially injected over periods of 10–15 seconds in 1-mL aliquots, forming a discrete aqueous reaction chamber. Congo red pH indicator was included to assess the reaction. A thermocouple allowed data collection at completion of injection and every 15 seconds for 5 minutes. Injections were performed in triplicate, and average temperatures for each time point were reported. Results Gelatins fractured or refluxed even at the lowest concentrations tested. Most commercial gels proved too viscous and likewise led to reflux along the needle tract. A mineral oil–based gel was selected because of its ability to form a chamber without reflux or fracture and its clear colorless character, hydrophobic nature, chemical stability, viscosity, specific gravity, and cost. Temperatures during the first 60 seconds of the neutralization reaction showed an immediate increase that correlated well with concentration. Conclusions The oil gel phantom is a safe, useful, readily available, inexpensive model to study mixing behaviors and maximum heating potentials for reactions that may prove useful in thermochemical tissue ablation for oncologic interventions. Measurable temperature changes occurred even at the lowest concentrations, and higher concentrations produced a greater release of heat energy. |
| Databáze: | OpenAIRE |
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