膀胱肿瘤冷冻消融系统冷冻性能实验研究

Freezing Performance of Cryoablation System for Bladder Cancer

本文采用球囊作为冷冻单元,液氮作为制冷剂,设计开发了经尿道膀胱冷冻消融系统并进行了原理系统试制,通过对不同制冷剂流量工况下(9.4~37.7 L/s)的降温特性、降温速率、制冷量进行系统的实验研究确定了系统冷冻性能,分析了不同流量条件下的冷冻消融特性及冷冻消融的温度变化特性。研究结果表明,本文所设计的冷冻消融系统的峰值降温速率最高可达到-5℃/s,最低温度不低于-72℃,改变制冷剂流量可实现冷冻消融最低温度在-72~-100℃范围内变化,随着流量的增加,制冷量明显升高,制冷量可由94 W提高至275 W。由此可见,该冷冻消融系统可满足不同冷冻深度的冷冻能量选择要求,可对膀胱肿瘤细胞造成有效冷冻坏死同时根据肿瘤大小实现不同冷冻深度可控选择。

A transurethral bladder cryoablation system is designed and developed by using balloon as the freezing unit and liquid nitrogen as the refrigerant. The principle system is assembled and the freezing characteristics, cooling rate and freezing capacity of the system were studied systematically under different refrigerant flow rate conditions(9.4-37.7 L/s). Accordingly, the freezing performance of the system was determined and the cryoablation performance and the temperature change characteristics are analyzed. The results show that the peak cooling rate of the cryoablation system is-5 ℃/s, and the lowest temperature is not higher than-72 ℃. The lowest cryoablation temperature is changing from-72 ℃ to-100 ℃ by changing the refrigerant flow rate. With the increase of the refrigerant flow rate, the freezing capacity increases significantly from 94 W to 275 W. It is revealed that the cryoablation system can supply suitable energy output for different freezing depths requirement. Thus, it can cause effective freezing necrosis of bladder tumor cells. Different freezing necrosis depth can be controlled according to the tumor size.