Modeling and ex vivo experimental validation of liver tissue carbonization with laser ablation

Shiguang Zhang; Chunlei Li; Lin Cao; Michael A J Moser; Wenjun Zhang; Zhiqin Qian; Bing Zhang

doi:10.1016/j.cmpb.2022.106697

Modeling and ex vivo experimental validation of liver tissue carbonization with laser ablation

Comput Methods Programs Biomed. 2022 Apr:217:106697. doi: 10.1016/j.cmpb.2022.106697. Epub 2022 Feb 10.

Authors

Shiguang Zhang¹, Chunlei Li², Lin Cao³, Michael A J Moser⁴, Wenjun Zhang⁵, Zhiqin Qian⁶, Bing Zhang⁷

Affiliations

¹ Intelligent Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China; School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China.
² Shanghai Advanced Research Institute, Chinese Academy of Science, Shanghai, 201024, China.
³ Department of Automatic Control and Systems Engineering, the University of Sheffield, Sheffield, UK.
⁴ Department of Surgery, University of Saskatchewan, Saskatoon, Canada.
⁵ Department of Mechanical Engineering, University of Saskatchewan, Saskatoon, Canada.
⁶ School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China. Electronic address: qianzhiqin@ecust.edu.cn.
⁷ Intelligent Energy-based Tumor Ablation Laboratory, School of Mechatronic Engineering and Automation, Shanghai University, Shanghai, 200444, China. Electronic address: bingzhang84@shu.edu.cn.

PMID: 35180678
DOI: 10.1016/j.cmpb.2022.106697

Abstract

Objective: The purpose of this study was to model the process of liver tissue carbonization with laser ablation (LA).

Methods: A dynamic heat source model was proposed and combined with the light distribution model as well as bioheat transfer model to predict the development of tissue carbonization with laser ablation (LA) using an ex vivo porcine liver tissue model. An ex vivo laser ablation experiment with porcine liver tissues using a custom-made 1064 nm bare fiber was then used to verify the simulation results at 3, 5, and 7 W laser administrations for 5 min. The spatiotemporal temperature distribution was monitored by measuring the temperature changes at three points close the fiber during LA. Both the experiment and simulation of the temperature, tissue carbonization zone, and ablation zone were then compared.

Results: Four stages were recognized in the development of liver tissue carbonization during LA. The growth of the carbonization zone along the fiber axial and radial directions were different in the four stages. The carbonization zone along the fiber axial direction (L2) grew in the four stages with a sharp increase in the initial period and a minor increase in Stage 4. However, the change in the carbonization zone along the fiber radial direction (D2) increased dramatically (Stage 1) to a long-time plateau (Stages 2 and 3) followed by a slow growth in Stage 4. An acceptable agreement between the computer simulation and ex vivo experiment in the temperature changes at the three points was found at all three testing laser administrations. A similar result was also obtained for the dimensions of coagulation zone and ablation zone between the computer simulation and ex vivo experiment (carbonization zone: 2.99± 0.10 vs. 2.78 mm², 67.39± 0.09 vs. 63.53 mm², and 90.53± 0.11 vs. 85.15 mm²; ablation zone: 68.95± 0.28 vs. 65.29 mm², 182.11± 0.24 vs. 213.81 mm², and 244.80± 0.06 vs. 251.79 mm² at 3, 5, and 7 W, respectively).

Conclusion: This study demonstrates that the proposed dynamic heat source model combined with the light distribution model as well as bioheat transfer model can predict the development of liver tissue carbonization with an acceptable accuracy. This study contributes to an improved understanding of the LA process in the treatment of liver tumors.

Keywords: Laser ablation; Liver tissue; Mathematical modeling; Monte Carlo simulation; Tissue carbonization.

MeSH terms

Animals
Computer Simulation
Hot Temperature
Laser Therapy* / methods
Lasers
Liver / surgery
Swine