Prostate cancer is a tumor that is sensitive to radiation therapy. For low- to intermediate-risk prostate cancer, radiotherapy has a survival rate that approximates that of surgery. The reason for this is that although radiotherapy has the same risk of urethral stricture and urinary incontinence as surgery, and even at the 10-year postoperative follow-up, their complication rates are basically the same; however, radiotherapy can eliminate the pain of surgery and the risk of urinary incontinence and fistula caused by surgery, so it is a good choice especially for patients older than 70 years old. Therefore, radiotherapy is a good choice, especially for patients older than 70 years old. There are two types of radiotherapy: external and internal. External radiation is a three-dimensional intensity-modulated radiation therapy that is administered in the body with high-energy rays from outside the body while the patient is lying on a radiotherapy bed, based on the results of magnetic resonance. However, the biggest problem with external radiation today is the immobilization of the prostate. The bladder above the prostate can drift slightly with respiratory movements, driving the prostate to drift slightly as well. Therefore, although the prostate has been positioned in 3D according to its shape prior to radiation therapy, the fluttering of the prostate can cause the prostate to drift slightly up and down within the radiation area during radiation therapy, resulting in the organs surrounding the prostate, especially the rectum and bladder, constantly moving in and out of the radiation area with respiration. Patients are often unable to continue radiation therapy before the local dose to the prostate has reached the treatment dose because the bladder and rectum are repeatedly irradiated by radiation resulting in symptoms such as severe urinary frequency, urinary urgency, painful urination, hematuria, urgency, thin stools, blood in the stool, sexual dysfunction, urethral stricture, recto-vesical fistula, and perianal ulceration caused by radioactive cystitis and radioactive proctitis. Therefore, the dose of local radiotherapy to the prostate may be much lower than the dose needed to kill tumor cells. (According to foreign studies, radiotherapy often requires a dose of 78 Gy to cure prostate cancer, while I personally have observed cases clinically up to 65-72 Gy, and the literature shows that the 10-year survival rate is significantly different for doses of 78 Gy and 70 Gy.) Therefore, external radiation requires proper fixation of the prostate if an adequate dose is to be achieved. The common method of fixation abroad is through simultaneous fixation by balloon catheter and balloon anal tube, but this method is more painful and may require the cooperation of a specialist urologist. There is no such fixation in domestic hospitals at present. The common method in China is body pad fixation, that is, the patient lies on a special body pad for radiotherapy. Although this fixation method is very painful, the effect of fixation is not good, and the patients fixed by body pad method often cannot reach 78Gy, thus cannot cure the tumor. Therefore, although patients with the double-tube fixation method of ureter and anal canal are more painful when going down the tube, this pain is insignificant compared to the pain caused by radiation cystitis and radiation proctitis due to radiotherapy, and compared to the pain caused by tumor progression after 5-10 years. Overall, weighing the pros and cons, a two-tube approach to immobilization should be performed. Another method of radiotherapy for prostate cancer is internal brachytherapy. This treatment is performed by transanal ultrasound localization, followed by perineal puncture into the prostate under ultrasound guidance, and approximately 5 mm long radioactive iodine 125 particles are placed into the patient through the puncture needle. This treatment, with a much higher local dose than external radiation, can reach 140-160 Gy. Also, because prostate cancer cells proliferate very slowly, and only a few cells are in the replication and division phase (a period of high sensitivity to radiation) every day, the killing effect of radiotherapy for about 20 minutes a day is limited. However, if the radiation source is implanted in the body and radiated continuously for 24 hours, the effect of radiotherapy can be expected to be greatly improved. Available data show that for patients with prostate cancer without bone metastases, internal brachytherapy has a 10-year survival similar to that of surgery. Even for high-risk patients, internal radiation combined with external radiation and anti-androgen drugs can achieve results similar to those of surgery. Therefore, especially for high-risk patients over 70 years of age without bone metastases, internal particle implantation may be the optimal choice for them. The price of radioactive particles varies from province to province and generally ranges from approximately 400-500 RMB per particle. Therefore, the main cost of this treatment for patients depends on how many particles are placed. The number of particles to be placed is determined by the volume of the prostate. The spacing between the particles is generally required to be approximately 25px, so each patient will need approximately 30-120 particles (depending on the volume of the prostate). If you want to save the particles, you can start with 6-12 months of anti-androgen therapy, such as using androgen receptor antagonists (bicalutamide, flutamide or enzalutamide) combined with GnRH mimetics (such as goserelin, leuprolide or treprostinil), and later on implantation therapy with radioactive particles. The approximate overall treatment cost for the radioactive particle implantation procedure is between $30,000 and $50,000. The penetration depth of radioactive particles in the body after implantation is about 1.7 cm, so it is difficult to detect radioactivity on the surface of the patient’s body if implanted. Moreover, the killing power of radiation is inversely proportional to the square of the distance, so if the patient keeps a distance of 1 meter from his family for 2 months after the operation, it is completely harmless to his family. after 2 months, the radioactivity of the particles decays to undetectable level, and after that, it is even gradually reduced.