基于超声背向散射积分的微波热疗无损测温

Noninvasive Temperature Estimation of Microwave Hyperthermia Using Ultrasonic Integrated Backscatter

旨在探索一种基于超声背向散射积分的微波热疗无损测温方法,利用水浴加热实验系统,以新鲜离体猪肝组织为研究对象,通过采集不同温度下的超声原始射频信号,分析各温度下组织的背向散射积分,建立背向散射积分与温度相关性模型用于微波加热实验过程中温度的检测.所建相关性模型为:超声背向散射积分值为0.062×t+3.591;该模型在低温段(≤70℃)测温误差较小(<5℃),在高温段(>70℃)测温误差较大(>10℃).研究结果表明:超声背向散射积分可用于常规热疗无损测温;微波热疗温度分布不均使得检测较为困难;利用正常与热凝固组织背向散射积分的差异进行热凝固区检测具有一定优势.

The objective of this study is to explore a new method for noninvasive temperature estimation of microwave hyperthermia using ultrasonic integrated backscatter( IBS). Water bath heating experiments were performed to fresh in vitro porcine liver tissues,and original ultrasonic radiofrequency signals at different temperatures were collected. IBS at each temperature was analyzed,and the correlation model between IBS and temperature was built for temperature estimation in microwave heating experiments. The correlation model was: IBS = 0. 062 × t + 3. 591. The correlation model based temperature estimation for microwave hyperthermia had a small error( < 5 ℃) in the temperature range ≤70 ℃,and a larger error( >10 ℃) in the temperature range >70 ℃. Experimental results indicate that: 1) IBS may be used for noninvasive temperature estimation of mild hyperthermia; 2) because of the heterogeneity of temperature distribution in microwave hyperthermia,it was difficult to estimate the temperature accurately; and 3) it may be a potential approach for detecting thermal coagulation zones based on the difference between the IBS of normal and coagulated tissues.