## 1 Introduction  
Brain tumors are one of the health problems that cause worldwide concern. Their incidence is increasing year by year and can occur at any age, accounting for \(5\%\) of adult tumor incidence and \(70\%\) of childhood tumor incidence [1], and they account for \(1.4\%\) of all cancers and \(2.4\%\) of all cancer deaths [2]. Common treatment methods include surgery, radiotherapy, and chemotherapy, but at present, the above methods have limitations for patients with brain tumors that are located deeper, adjacent to functional brain areas, difficult to reach by surgical route, and in poor general condition, so thermal ablation has become one of the scientifically effective methods. The treatment principle of this procedure is to cause coagulation necrosis of brain tumor cells through local high temperatures with minimal damage to the surrounding normal brain tissue. Laser Interstitial Thermal Therapy (LITT) technique is safe, minimally invasive, and effective for lesions that are more difficult to access through open access, deeper lesions, and patients who may not be able to tolerate open surgery. Therefore, it has become the most commonly used ablation technique for the treatment of brain tumors worldwide. LITT uses light to produce a photothermal effect in the tissue to cause coagulation necrosis of brain tumor cells [3]. The clinical application is guided by magnetic resonance imaging. One or more optical fibers are delivered to the patient's brain tumor, where the laser is deposited at low power and a long exposure time, increasing the temperature in the target area for tissue destruction [4]. When ablating under-exposed intracranial tumors, the target temperature of LITT is set at 45-90 \({}^{\circ}\)C [5], which achieves the critical temperature for tissue necrosis to occur while avoiding charring and vaporization of the tissue due to high temperature. At the same time, edema is also avoided because the transition zone between the target area and the surrounding normal brain tissue is less than 1 mm. To accurately predict the temperature change and damage in the focal area, more and more scholars have proposed exploring the temperature field changes by real-time simulation and reconstruction of the tumor/surrounding tissue in the target area through finite element simulation techniques [6; 7]. However, various related studies have shown that tumor tissue usually grows more abundantly near blood vessels. During laser heating, the blood flow in the blood vessels takes away some of the heat and affects the distribution of the temperature field. The micro-vessels system in the tissue is disrupted during ablation, and the blood vessels near the target area are prone to coagulation effects. At the same time, the imaging techniques currently used in clinical practice (e.g., conventional CT and MRI) have too low a resolution in detecting small vessels [8] (<1 mm in diameter), making the study of small vessel effects necessary. [PERSON] et al. [9] presented an energy equation for tissue heating and split the regions of interest into tissue perfusion areas and blood vessel-containing capillary areas. [PERSON] et al. [10] considered the effect of four different vessels on the ablation situation in capillaries, terminal arteries, terminal branches of arteries, and tertiary branches to make the simulation more realistic. Still, they focused on using each vessel as a liquid phase to explore the effect of porous media on the temperature field. To assess the small vessel heat transfer mechanism during the heating of biological tissues, [PERSON] and [PERSON] [11] suggested a study approach to model cylindrical parallel tiny vessels as forward/reverse flow vascular networks. The approximate modeling of blood vessels was performed using the Pennes equation and the one-dimensional convective diffusion equation (constant heat transfer coefficient of the blood vessel wall). They discovered that when distance shrank, blood vessel volume grew, there were more blood vessel branches, and the cooling impact grew.