[FKFU-A319-00-A] Numerical Simulation of Transpupillary Thermotherapy for Intraocular Tumors
작성자
플로우마스터코리아
작성일
2021-09-17 11:42
조회
35
The use of computational methods in medicine, especially in practical medicine, is not widely spread. Primarily this is due to the difficulty of modeling specific medical procedures and their effects on the human organism, as well as the conservatism of the methods of treatment used for this. However, recently new methods of treatment of oncological diseases connected both the use of radiology and laser radiation, are emerging at a rapid rate.This article considers one of the therapy methods that treats the tumor on the circulatory eye system (choroid) that provides blood to the retina of the human eye. A tumor occurs within the retina or the choroid. Currently, there are three main organ-preserving methods of treatment such tumors: Brachytherapy, Laser Thermotherapy and Stereotactic Radiosurgery (gamma-knife).
The Brachytherapy method uses a special applicator covered with radioactive elements Ru106 and Rh106 which is placed on the sclera from inner side of human eye. Radioactive radiation destroys tumor cells. To destroy the tumor, the tumor tissues must receive the necessary dose of radiation. This method can treat tumors up to 7mm in thickness.
Laser Thermotherapy is connected with heating the tumor tissues with a laser beam at continuous mode operation. The laser beam is directed through the pupil (transpupillary) to a tumor located under the retina, passing through all the structures of the eye. In order to ensure minimum absorption of the beam in the eye structures, a monochromatic laser with a wavelength of 810nm is used. Such radiation is characterized by a relatively weak absorption (less than 5% [1]) of the transparent structures of the eye, which allows the laser beam to act directly on the tumor. The tumor heats up to a temperature of around 45°C or more, which leads to necrosis of the tumor tissues. This method can treat tumors up to 3mm in thickness.
The method of Stereotactic Radiosurgery uses focused gamma radiation sources, which acts on the tumor locally and destroys its tissues.
The main goal of the work is to conduct a numerical simulation of the treatment of a choroid tumor by the Transpupillary Laser Thermotherapy using FloEFD.
The therapeutic basis of the method of laser thermotherapy is hyperthermia, which suppresses growth and destroys tumor cells. In order to avoid coagulation and destruction of protein structures, laser radiation must have a strictly defined level of power that does not lead to the burning of internal structures of the eye. Currently, the reference point for selecting this power is the clinically visible change of the tumor surface color (whitening) when laser radiation is applied to it for one minute. Such impact is considered as optimal. Unfortunately, at the present time it is not possible to measure both the temperature of the tumor and the temperature of the surrounding tissues, so numerical simulation is one of the methods which allows to estimate not only the levels of these temperatures, but also the temperatures of nearby eye structures, for example, the retina, optic nerve, choroid etc.