3D simulation of platelet aggregation in cryosurgery

In cryosurgery for cancer treatment, cells are injured not only by freezing but also by vascular stasis. The vascular stasis caused by thrombosis necrotizes the surrounding non-targeted cells due to the lack of oxygen and nourishment. Inhibition of thrombus formation, which is the former phase of the vascular stasis, is required to prevent damaging normal cells around a tumor. Foregoing studies simulated platelet aggregation based on distance between platelets. However, in cryosurgery, temperature dependency of blood-clotting factors' activity is required to be considered. The authors constructed a three-dimensional model consisting of vascular and extra- vascular tissues, and simulated heat transform and platelet aggregation. Heat transform was analyzed by boundary fitted coordinates method, and platelet aggregation was analyzed by particle method. The probability of bonding between platelets is derived from chemical reaction kinetics. The results showed larger size of simulated thrombus on higher temperature. The simulation with varied temperature around destructed area showed platelet aggregation depending on temperature.