Radiation therapy, including external and internal radiotherapy, can be effective in controlling prostate cancer. Compared to external radiotherapy, internal radiotherapy ensures that there is a large dose of radiation to irradiate the cancer confined to the prostate, while having the advantage of minimal radiotoxic damage to its surrounding normal tissues. However, as with radical prostate cancer surgery, the effectiveness of specific particle placement must be evaluated based on the size, location, and stage of the patient’s tumor. After all, compared to radical surgery to completely remove the tumor, particle implantation uses radioactivity to kill the tumor. The radiation range of the particles is limited, and sometimes it is inevitable that a small portion of the tumor may not be completely radiated during the implantation process, and some patients may even urinate the particles out during urination, so tumor involvement or recurrence may occur. However, in general, particle implantation is another promising method to cure limited prostate cancer after radical prostatectomy and external radiotherapy, and has a promising future.