Effect of adjuvant on cutaneous cryotherapy

Abstract

The present study is carried out to quantify the effect of NaCl in 0.6% (w/v) agarose gel for cryosurgical applications. The concentration of NaCl is taken as 0%, 5%, 10% and 20% (w/v). In this study liquid nitrogen is sprayed using a 0.8 mm nozzle diameter. The distance from the nozzle to the agarose gel surface is 27 mm. The spray cooling is carried out for a single freeze-thaw cycle (freezing 120 s and thawing 130 s). The transient temperature history and ice front are measured experimentally. To validate the numerical study with the experimental study, energy equation with phase change is considered. The numerically calculated results show good confirmation with the experimentally measured results. The ablation volume, lethal front and gap (distance between lethal front and ice front) are calculated numerically as these parameters are difficult to determine experimentally. The lowest temperature, obtained at the end of 120 s of freezing, decreases with the increase in the NaCl concentration in the gel phantom. The ice front obtained in the radial and axial directions decreases with the addition of NaCl concentration in the gel. The ablation volume enclosed by − 25 °C isothermal surface in the case of 20% NaCl-gel is 111% larger than 0% NaCl-gel while it is 64% for − 50 °C isothermal surface. It is interestingly found that the calculated gap decreases with the addition of NaCl concentration.