Comparisons of Sequential and Simultaneous Acid–Base Injections During Thermochemical Ablation: A Computational Study

Thermochemical ablation (TCA) is a minimally invasive technique for treating cancer by applying localized heat generated from chemical reactions to eradicate cancerous tissue. One preferred exothermic reaction involves the neutralization between hydrochloric acid (HCl) and sodium hydroxide (NaOH), resulting in safe by-products like water and sodium chloride (NaCl). The administration of acid and base can occur in a sequential or simultaneous manner. In the sequential approach, either the acid or the base is introduced into the tissue first while the simultaneous approach involves combining both acid and base in the distal tip of a dual-lumen needle, resulting in a heated salt solution that is injected into the tissue. However, the progress of TCA has been limited to preclinical stages due to a lack of comprehension regarding how the reagents flow within the tissue. An inherent risk of TCA is the unpredictable reagent flow within the tissue, which poses a potential threat to patients. Current experimental methods do not provide visualization of the flow, neutralization, heat release, tissue temperature rise, and thermal damage. A mathematical and computational framework for TCA has been recently developed and applied to simulate TCA using both delivery methods. Through numerical predictions, the study revealed the thermochemical processes occurring within the tissue during TCA. The sequential injection approach failed to sustain high tissue temperatures and caused minimal damage, whereas the simultaneous injection approach effectively maintained elevated tissue temperatures, leading to significant thermal damage. These numerical predictions demonstrated reasonable agreement with experimental results reported in the relevant literature.