Radio Therapy Balloon Catheter, a material for fixing in the body of radiation therapy, is a disposable treatment material inserted into the rectum to minimize the movement of the treatment area during external radiation therapy such as prostate cancer. In external radiation therapy, it is inserted into the body cavity to secure an intentional space for the purpose of improving the treatment effect using radiation characteristics, and minimizes the movement of the treatment area due to breathing, which plays an auxiliary role in the implementation of Image-Guided and Intensity-Modulated Radiation Therapy. It also reduces radiation exposure to the rectum by discharging gas in the rectum and providing more consistent treatment conditions in repeated treatments.