Abstarct: Accurate estimation of temperature distribution is a main and critical factor in hyperthermia which is considered as a combination treatment for cancer tumors. In heperthermia very high temperatures are used to kill the cancer cells and destroy nearby blood vessels which were weaknesses by other treatment methods. Very high temperatures can kill cancer cells outright (thermal ablation), but they also can injure or kill normal cells and tissues. This is why hyperthermia must be carefully controlled. This thesis represents a new method for estimating heating power of source in order to destroy cancer cells of breast due to the temperature distribution in the breast tissue. The geometry of breast is represented as a hemisphere containing three laxyers, muscle, gland and fat. The conjugate gradient method is used to solve the inverse
heat conduction problem using Pennes bioheat equation in the axisymmetric coordinate system. To make the solve of the problem easier, the irregular region
in the physical domain (r,z ) is transformed into a rectangle
in the computational domain (ξ , η). The temperature changes across target tissue is measured using adjacent sensors. The problem was solved in two different conditions at first by employing one sensors and in another examination, temperature changes were measured using two sensors. To achieve a good accuracy, three equation are used to estimate temperature distribution during the tissue and solution was presented in two different conditions, one and two sensors, in order to achieve good evaluation of suggestion method. The results shows appropriate accuracy of algorithm that makes it practical.