TY - JOUR
T1 - A Hydrophobic Gel Phantom for Study of Thermochemical Ablation
T2 - Initial Results Using a Weak Acid and Weak Base
AU - Misselt, Andrew J.
AU - Edelman, Theresa L.
AU - Choi, Jeung H.
AU - Bischof, John C.
AU - Cressman, Erik N.K.
PY - 2009/10
Y1 - 2009/10
N2 - 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.
AB - 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.
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U2 - 10.1016/j.jvir.2009.06.027
DO - 10.1016/j.jvir.2009.06.027
M3 - Article
C2 - 19699659
AN - SCOPUS:70349470972
SN - 1051-0443
VL - 20
SP - 1352
EP - 1358
JO - Journal of Vascular and Interventional Radiology
JF - Journal of Vascular and Interventional Radiology
IS - 10
ER -