 Gold nanoparticles, ONPs, have gained significant interest due to their unique optical, electronic, and physical chemical properties. These properties make them ideal candidates for a variety of medical applications such as drug and gene delivery, photothermal therapy, PTT, photodynamic therapy, PDT, and radiation therapy, RT. Additionally, they can also be used for X-ray imaging, CT scans, and other biological activities. This review provides a comprehensive overview of the synthetic methods, characterization techniques, and applications of ONPs in the medical field. This article was authored by Xiaopei Hu, Yuting Zhang, Tingting Ding, and others.