The intense optical properties of plasmonic nanoparticles make them ideal as contrast agents for light-based imaging techniques. Metallic nanorods of 1-Dimensional morphologies have two plasmon bands; the transverse and the longitudinal plasmon bands. The transverse plasmon band is due to the oscillation of free electrons along the short axis and the longitudinal plasmon band is due to the oscillation of free electrons along the long axis of the nanorod. By changing the length and width of the nanorod, the longitudinal plasmon band can be red-shifted towards the near-infrared region where light penetration in tissue is high which is useful for in vivo imaging applications. For specific targeting, metallic nanorods can be bioconjugated with antibodies that bind to tumor cells. These functionalized metallic nanorods, when administered into the subject, permeate into leaky vasculature of tumors and bind to tumor cells. We use photoacoustic imaging (PAI) as a non-invasive imaging technique, which produce strong ultrasound signals when metallic nanorods are irradiated and identifies the location/size of tumor margins. In addition to imaging, therapy of cancers is also possible by inducing hyperthermia to tumor cells.