Development of a Flexible Cooling System for Photothermal Ablation of Peripheral Lung Tumors

Effat, Andrew 1, 2 ;  Yasufuku, Dr. Kazuhiro 1, 2, 3

1. Institute of Biomaterials and Biomedical Engineering, University of Toronto; 2. Latner Thoracic Surgery Research Laboratory, Toronto General Hospital Research Institute, University Health Network; 3. Division of Thoracic Surgery, Toronto General Hospital

Purpose: The purpose of this project is to develop a flexible cooling catheter that can eliminate excess heat related problems, such as necrosis of surrounding tissue and damage to the optical fibre, that occur during endoscopic photothermal therapy (PTT) of peripheral lung nodules.

Hypothesis: If we drive a coolant fluid near the tip of the fibre that can dissipate the excess heat produced by the optical fibre, then we can reduce or eliminate the heat related issues, and greatly improve the efficacy of PTT as a viable treatment for peripheral lung nodules.

Methods: The first aim of this project is to design and develop a functional prototype of the cooling system, to allow us to test the impact that it will have on reducing the heat related damage that accompanies PTT treatment. The second aim is to test this device using a phantom that will mimic the coagulation of human tissue, to allow us to gauge the device’s performance, and modify the design to further improve its effectiveness. The third aim is to test the design in a perfused, ex-vivo human lung, to allow for further confidence that the testing done in the lab will yield a high rate of translation to the clinical setting.

Results: A prototype has been manufactured and tested for functionality. A polyacrylamide phantom is in development, and testing is underway to validate that the temperature outside of the target area remains below 50°C, and that there is no charring of the optical fibre.

Conclusion: The successful implementation of this cooling system will allow for improved efficacy of PTT, and validate it as a viable treatment for currently inoperable cases of peripheral lung nodules. Its use can also be spread to other treatment tools, such as radiofrequency ablation, which are accompanied by concerns over heat related harm that can be caused to the patient.