Nanomedicine has been developing rapidly in recent years, particularly in the development of novel Nano tools for medical diagnosis and treatment. For instance, a new trend is becoming prevalent in developing Nanosystems for simultaneous tumour diagnosis and therapy. A new terminology "Theranostics" has been frequently used and applied in pre-clinical research and trials. A Nanosystem can simultaneously achieve both cell targeted in vivo imaging and photothermal treatment of cancer. While achieving concurrent high spatial and temporal resolution of the lesions via cell targeting; special non-evasive treatments are implemented at the same time by various means, such as localized drug release, hyperthermia, and photo-thermal therapy. Inspired by these challenging problems in biomedical fields, the development of the nanotechnologies will be the key in addressing some of the critical issues in medicine, especially in early cancer diagnosis and treatment.