Minimally invasive tumor treatment has gradually become a new trend in the development of tumor treatment in the 21st century, in which 125I particle implantation brachytherapy is an important part of minimally invasive tumor treatment, which uses 125I particle implantation brachytherapy to kill or inactivate tumor tissues to the greatest extent, and even achieve clinical cure, i.e., clinical symptoms disappear, imaging shows that the lesion disappears, and relevant laboratory tests are negative. activity disappears, and relevant laboratory tests are negative. If, on this basis, the patient’s specific condition and physical condition are taken into account, the sequential combination of other tumor treatments, such as oncologic chemotherapy or precise external radiotherapy, will achieve better therapeutic effects. Therefore, 125I particle implantation is an effective method for treating malignant tumors with the characteristics of simplicity, safety and high efficacy, which adds a new therapeutic means for the comprehensive treatment of tumors. 1. Radioactive particle implantation is suitable for localized (limited) tumors. There is no distant metastasis, the maximum diameter of tumor should be less than 7cm, slow growth and good differentiation; the patient has KPS score of 60 or above and no important organ failure. There are a wide range of diseases suitable for particle implantation treatment, including glioma and brain metastases; nasopharyngeal and orbital tumors, oropharyngeal cancer, tongue cancer, floor of mouth cancer, buccal mucosa cancer, neck metastases; lung cancer, pleural mesothelioma, breast cancer; bile duct cancer, liver cancer; prostate cancer, gynecological tumors; soft tissue and bone tumors. 2.Treatment Planning System (TPS) for particle implantation. The American Brachytherapy Society requires that all patients treated with particle implantation must have a preoperative treatment plan. The expected dose distribution is given. The standard practice is to use CT, MRI, ultrasound images and other imaging to determine the target area, and to develop the number of implanted guide needles, the number of particles and the particle activity and total activity according to the tumor contour and cross-section. The dose distribution is observed by TPS, and the guide needle and particle positions are adjusted to obtain the optimal dose distribution.