Acta Optica Sinica, Vol. 40, Issue 24, 2417001 (2020)
Effect of Inserted Optical Fiber on Light Absorption in Biological Tissue for Finite-Diameter Photon Beams
Dai Lijuan1,*, Ding Leming1, Li Weitao2, and Qian Zhiyu2
- 1School of Mechanical Engineering, Nantong University, Nantong, Jiangsu 226019, China
- 2College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210046, China
In this paper, we established a double-layered spherical model of tissues with an inserted optical fiber, considering that a finite-diameter photon beam was emitted from the optical fiber embedded in the tissue during the laser-induced interstitial thermotherapy (LITT). Firstly, based on the Monte Carlo method, we obtained the absorption of an infinitely narrow beam in the tissue. Then, we attained the light transmission equation of a finite-diameter photon beam through the convolution between the incident light intensity and the Green's function. Finally, taking a Gaussian beam and a flat-topped beam as examples, we compared the changes in the absorption of the finite-diameter photon beam with or without considering the inserted optical fiber. The results show that the absorption of tissues for the flat-topped beam is smaller than that for the Gaussian beam. Besides, the influence of the inserted optical fiber on the absorption of the flat-topped beam is smaller, whereas its influence on the absorption of the Gaussian beam near the photon emission center is larger. Therefore, the influence of the inserted optical fiber on the absorption of light energy of tissues should be considered in LITT using the Gaussian beams. The proposed model follows the actual situation of LITT, which is of great significance for accurately predicting the thermal damage range of LITT.
Please Enter Your Email: