Department of Radiology, University of Minnesota Medical Center, Minneapolis, MN 55455, USA.
J Vasc Interv Radiol. 2009 Oct;20(10):1352-8. doi: 10.1016/j.jvir.2009.06.027. Epub 2009 Aug 21.
To develop a model for study of exothermic chemical reactions potentially useful for tissue ablation.
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.
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.
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.
开发一种用于研究放热化学反应的模型，该模型可能对组织消融有用。
评估了从 0.5%到 30%重量/体积的七种明胶，有无 15%或 30%胶囊，以及几种商业凝胶。进行了基线温度测量。醋酸和氨水以 1 毫升等分试样的形式在 10-15 秒内连续注入，形成离散的水相反应室。刚果红 pH 指示剂用于评估反应。热电偶允许在注射完成时和之后每 15 秒收集数据 5 分钟。重复进行三次注射，并报告每个时间点的平均温度。
即使在测试的最低浓度下，明胶也会破裂或回流。大多数商业凝胶由于过于粘稠，同样导致沿着针道回流。选择一种矿物油基凝胶，因为它能够形成一个没有回流或破裂的腔室，并且具有清晰无色的特性、疏水性、化学稳定性、粘度、比重和成本。中和反应最初 60 秒内的温度立即升高，与浓度密切相关。
油凝胶模型是一种安全、有用、易于获得且廉价的模型，可用于研究混合行为和可能对肿瘤介入热化学组织消融有用的反应的最大加热潜力。即使在最低浓度下也会发生可测量的温度变化，较高浓度会产生更大的热能释放。
