Investigation of bio-heat transfer for cancer treatmet using cryo-freezing method

Cryo-therapy is an effective medical treatment that is used to destroy tumors by placing cryo-probes that cause frozen tissue in the biological tissue. It is considered as a good treatment option due to minimal recurrence and short hospitalization for cancer treatment. In this study, the effect of bio-heat transfer from large blood vessels on the freezing zone size of tumorous liver tissue is investigated using the cryo-freezing method. Bio-heat transfer in tumorous tissue with and without blood vessel for cancer treatment has been investigated experimentally and numerically using cryo-freezing method. Investigated parameters are the blood mass flow rate, the diameter of vessel, the number of vessel, and the location of tumorous tissue. Study is carried out for eleven different blood mass flow rates varying from 10 g/min to 1200 g/min. Tissues without blood vessel, with single, double and branched vessels are used for the experimental and numerical study. Vessels with inner diameter of 2.4 mm, 3.2 mm and 4.0 mm are used. Beef liver is used as a biological tissue. Nitrogen protoxide (N2O) gas is employed as refrigerant. Results show that the number of vessel, the diameter of vessel, the location of tumorous tissue, and the blood mass flow rate affect the freezing region size. Freezing region size decreases with increasing in diameter of vessel, number of vessel and blood mass flow rate. The large blood vessel located near the tumorous tissue affects the freezing time to destroy the tumor. The desired freezing region obtained in tumorous tissue with vessel develops later than the tumorous tissue without vessel. Results indicate that a tumorous tissue about 23 mm may be destroyed in a short time using cryo-freezing method when nitrogen protoxide gas is used as refrigerant gas.