Gold is one of the first metals to have been discovered; the history of its study and application spans at least several thousand years. In particular, the optical properties of GNP are determined by their plasmon resonance, which is associated with the collective excitation of conduction electrons and localized in the broad region. The application of nanotechnology for the treatment of cancer is mostly based on early tumor detection and diagnosis by nanodevices capable of selective targeting and delivery of chemotherapeutic drugs to the specific tumor site. The nanotechnology-based detection and diagnostic methods used are Magnetic resonance imaging (MRI), Optical coherence tomography (OCT), Photoacoustic imaging, Surface plasmon resonance scattering, Surface-enhanced Raman spectroscopy, Diffusion reflection imaging, Quantum dots imaging, and Nano-based ultrasensitive biomarker detection.