There are internal radiotherapy and external radiotherapy. The majority of clinical choices are still external radiation. In recent years, with the advancement of science and technology and the development of imaging, internal radiotherapy has been developed rapidly, and iodine 125 radioactive particle implantation is a prominent representative. However, external irradiation is still the most common choice in clinical practice. So what is the difference between the two? 1. External irradiation is a non-invasive operation, and the operation technique is quite simple; while iodine 125 particle implantation is an invasive operation, and the operation technique is relatively complicated. 2. External irradiation has a larger scope and lower dose, generally speaking, 5000cGY~7000cGY, while iodine 125 particle implantation has a smaller scope and higher dose, which can reach 12000cGY or even 16000cGY. 3. In terms of efficacy, iodine 125 particle implantation has a higher local control rate, which means better tumor control compared to external irradiation. 4. In terms of side effects, iodine 125 particle implantation has a smaller impact on the human body than external irradiation and has fewer side effects. 5. In terms of treatment time, iodine 125 particle implantation is a single implantation, and the continuous effective irradiation time is 6 months, while external irradiation is usually 1 time a day, 5 times a week, and the general treatment is 1-2 months. In terms of reliability, iodine 125 particle implantation depends more on the surgeon’s surgical level, while external irradiation depends on the machine and the doctor’s daily positioning. In terms of economy, the smaller the tumor, the better the effect of iodine 125 particle implantation and the lower the cost. Therefore, the trinity of iodine 125 particle implantation to control local lesions, low-dose chemotherapy to eliminate distant metastases, and Chinese medicine to reduce toxicity and increase effectiveness and mobilize the immune system to completely destroy tumors can effectively kill tumors, reduce the side effects of treatment and improve the quality of life of patients. The efficacy of more than 1,000 surgical patients in 8 years proves that iodine 125 radioactive particle implantation is a safe, reliable treatment with few side effects that patients can choose.