This work provides detailed information on the significance of gold nanoparticles in medicinal applications. Gold has a wide range of uses and can be used in advanced applications in the nanometer range. In this research, we study the effectiveness of the integration of microwave coagulation theory with gold nanoparticles to study the extent of necrosis of tumor tissue. We perform photo-thermal therapy (PTT) with the illumination of gold nanoparticles with a pulsed laser beam to generate heat in the tissue to eradicate the tumor. The Gold nanoparticle is used due to its properties in performing PTT such as having localized plasmon surface resonance which enables them to absorb light at particular wavelengths. The results are evaluated by creating a 2D-axisymmetric model in COMSOL multiphysics. This model calculates the specific absorption rate (SAR), the extent of necrosis of tissue, the radiation field, and the temperature field.