A Temperature-Controlled Laser Hot Needle With Grating Sensor for Liver Tissue Tract Ablation
Hani Hareiza Abd Raziff, Daryl Tan, Kok‐Sing Lim, Chai Hong Yeong, Yin How Wong, Basri Johan Jeet Abdullah, Norshazriman Sulaiman, Harith Ahmad
Abstract
In this article, we proposed a laser hot needle for liver tissue tract ablation. The proposed laser hot needle is powered by a 4500-nm-diode laser incorporated with a closed-loop control system that comprises of a uniform fiber Bragg grating (FBG) temperature sensor and a computer. Based on the real-time feedback input from the FBG temperature sensor, the laser power is regulated by a proportional-integral- derivative (PID) control system to control the needle temperature. In the characterization test, a chirped grating-based distributed temperature sensor is employed for measuring the tissue temperature profile in the ex vivo bovine liver tissue during the ablation. A histological test is conducted to study the impact of tract ablation to the cellular structures of treated tissue and tissue coagulation. In a tract ablation test, a ~50-mm × ~6-mm (length x width) thermal denaturation zone has been created on ex vivo bovine liver tissue with the laser hot needle at 150 °C.