激光诱导间质热疗中生物组织吸收系数变化特性研究

利用近红外光谱技术进行生物组织激光诱导间质热疗（laser induced interstitial thermotherapy, LITT）实时监测，探讨LITT术中疗效评估基础。实验样本采用离体猪肝和小鼠皮下移植肝肿瘤，使用近红外光谱实时采集系统采集激光热疗过程中组织吸收系数。实验结果表明组织吸收系数在激光热疗过程中具有一定的变化规律，其中猪肝的变化规律非常明显，在低功率下呈现缓慢的上升，高功率下达到一定的温度（50℃左右）快速上升，并逐步达到稳定。肿瘤在热毁损时会根据瘤体的组织特性不同出现特异性变化，这些变化可以作为将来临床治疗的参考。实验结果表明在进行实体组织激光诱导间质热疗过程中，组织吸收系数作为实时监测因子具有一定的参考价值，而作为肿瘤的治疗评估因子还需要进一步探索。

Change of absorption coefficient of biological tissues in laser induced interstitial thermotherapy

The feasibility of real-time monitoring in laser induced interstitial thermotherapy（LITT） of biological tissues using near infrared spectrum technique is explored and validated. In vitro liver and rats with subcutantaneous implanted tumor models were chosen as experiment objects. Changes of absorption coefficient of tissue are real-time measured by near infrared spectrum system in laser induced interstitial thermotherapy .The result indicates that absorption coefficient  has some variations during LITT. The change law of absorption coefficient  in vitro livers experiments is significant. It slowly goes up under low power, and rises greatly based on high power when biological tissues reach certain temperature(around 50℃) . The change laws of absorption coefficient during tumor experiments is different according to characteristics of tumor tissue which can be used for future clinical treatment. Experimental results show that absorption coefficient has valuable reference as a real-time monitoring factor in LITT of entity organizations, but it also needs further study as evaluating factor of the tumor treatment appraisal.