A non-invasive and real-time optical method for detection of cancerous cells that includes the steps of optically irradiating an area of a tissue in which targeted nanoparticles are accumulated with a light source outputting an optical signal of ne or more specific wavelengths identifying cancerous cells by measuring diffusion reflection of the irradiated tissue where the cancerous cells and the nanoparticles are located and outputting data indicative of the identified cancerous cells.
