Image-guided thermochemical ablation: Theoretical and practical considerations

Purpose: To test thermochemical ablation for potential as a new method to coagulate tissue and create a prototype device for administration. Materials and Methods: Reactions of either HCl or acetic acid and either NH₄OH or NaOH were run in triplicate in a gel phantom as a simple calorimeter. Data were recorded over a period of 5 minutes using concentrations from 1-12M in the case of HCl and NH₄OH. Comparison reactions were run at 11M using each acid reacted with each base. Two early device prototypes were devised using readily available components. Results: Maximum temperature rise was nearly instantaneous and was observed to peak with the 12M solutions at 106^oC. The maximum temperatures in the 11M comparisons were seen with the strong acid HCl paired with the strong base NaOH. The lowest temperatures were seen with the weak acid acetic acid paired with the weak base NH₄OH. Conclusion: Thermochemical ablation reactions can release adequate amounts of heat energy to cause tissue ablation.