Cardiovascular disease is one of the most common heart diseases in which the ducts of the veins gradually become tight and blocked. Every year, about a quarter of the world's deaths occur due to coronary artery disease. In intraluminal angioplasty of the coronary arteries a balloo is used at the site of the vessel clogging and, if necessary, a stent as a vessel scaffold , is used to keep it open. Although the prevalence of stenosis is significantly reduced with coronary stent implantation, the amount of re-stenting in the blood clot in the treatment site after angioplasty is 30% to 40% of the tests. For many decades, many types of radiation therapy for this angioplasty have been proposed. Here, our goal is a specific type of brachytherapy in which the optimal management of the radiation dose of the inner wall of the vessel is addressed to prevent its recurrence. Relevant sources for this action are beta-emission emitters, which can be referred to as Re-188, P-32, Sr-90, Y-90, Xe-133. In this dissertation, a gas balloon containing Xe-133 and CO2 gases has been used to prevent revascularization of the vessel, which is assisted by the Monte Carlo calculation technique using the MCNPX code. The dose rate in this angioplasty shows inversely proportional to the balloon thickness and the balloon radius. Dose rate for the balloon (3mm,40mm) with a thickness of 80 microns at a distance of about 0.125 mm from the balloon surface was about 700 cGy/mCi per hour, Doubling the balloon radius, the dose rate decreased to about 285 cGy / mCi per hour. When the balloon length was doubled, the dose rate decreased to 356 cGy / mCi per hour. This reduction in the dose rate is due to the self-absorption of gases inside the balloon .