探讨了基于可见-近红外光谱的生物组织激光热毁损实时监测的可行性。采用5 W、 808 nm激光对新鲜离体猪肝进行了热毁损实验,在距离毁损中心4、8、12 mm处实时采集可见-近红外光谱(330～1100 nm), 选取波长720 nm的散射光强(R d 720)作为评判因子。结果表明:加热初期R d 720随组织温度升高而快速增强,光 谱测量点与毁损中心距离越小, R d 720上升越快；达到有效毁损后,若保持加热,则温度继续上升 而R d 720趋于平稳;停止加热后,组织温度逐渐恢复到室温,而R d 720微降后基本保持不变且远高于初始值。 由此可见,生物组织的可见-近红外散射光强可以作为激光热毁损实时监测的一项重要参数。

The feasibility of real-time monitoring on biological tissue laser thermal damage based on visible and near-infrared spectroscopy is investigated. Thermal damage experiment is carried out in fresh porcine livers with laser of 5 W, 808 nm. Visible and near-infrared spectra (330～1100 nm) are acquired in real time at distances of 4, 8, 12 mm from the damage center, and the diffused light intensity at 720 nm (R d 720)is chosen as the evaluation factor. Results show that R d 720 increases quickly with the increasing of tissue temperature in the initial stage of heating. The smaller the distance between the spectral measurement point and damage center is, the faster R d 720 will increase. After reaching the effective damage, temperature continues to rise while R d 720 tends to be stable if keeping heating. After the heating is stopped, the tissue temperature gradually returns to room temperature, while R d 720 decreases slightly and remains almost a constant which is far higher than its initial value. It can be found that the visible and near-infrared scattering intensity of biological tissue can be used as an important parameter to real-time monitoring laser thermal damage.