"According to the World Health Organization (WHO), cancer is a leading cause of death worldwide. Among the distinct types of cancer treatments, surgery, which is the oldest modality, is still often confronted with difficulties in the identification of cancer spread and the accurate delineation of tumor margins. This is of uttermost importance in order to infer the lowest harm to the organ where the tumor originated but without leaving residual tumor. This proposal is intended to improve the surgical outcome, employing a highly sensitive fluorescence imaging approach, which holds a strong potential to become a key technology in intraoperative imaging.The primary goal is to employ real‐time multi‐spectral fluorescence imaging for sensitive and quantitative molecular visualization of infiltrating cancer, which can enable real‐time surgical feedback and improved surgical outcome over the current state of the art and clinical practice. For this goal an advanced multi‐spectral fluorescence imaging system that can significantly improve quantification and the observation accuracy over simple fluorescence video systems considered in the past, will be developed. Further promising new fluorescence probes will be utilized and their ability to offer high detection sensitivity and specificity of tumor margins will be investigated. The performance of this approach will be examined in controlled phantoms and in‐vivo in breast cancer and abdominal cancer in animal models. Moreover, the method will be examined in relation to offering real‐time pathology of lymph‐nodes in‐vivo.If this proposal is successful, it will lead to the development of an accurate imaging platform that can enhance surgical vision while seamlessly integrating in the operating surgical room. Due to the direct relation of the surgeon’s vision to optical methods and the relatively low cost and non‐ionizing energies used, a high dissemination potential into the surgical healthcare is expected."