Deep-seated tumors were investigated using a transgenic mouse model spontaneously developing tumors in the lung (Kras, 36). Mice at the age of approximately 15–18 weeks were injected intravenously before imaging with, respectively, 2 nmol of two different fluorescence probes, one targeting -integrins (IntegriSense680, Perkin Elmer, Waltham, Massachusetts) and a blood-pool agent (AngioSense750 Perkin Elmer, Waltham, Massachusetts). The excitation/emission maxima of IntegriSense680 and AngioSense750 are approximately at and , respectively. AngioSense can be used in oncology to study angiogenesis and was, therefore, chosen to provide information on vascularization and perfusion, in addition to the molecular information granted by the -integrin overexpression. AngioSense was injected in different mice both 1.5 and 24 h prior to imaging but did not show significant biodistribution differences between these two time points as confirmed by ex vivo validation studies. We hence only show, herein, results from a mouse injected 24 h prior to FMT-XCT measurements, i.e., at the same time point for which IntegriSense data was also acquired. This study examined, therefore, a physiological parameter (vascularization/perfusion) and a molecular parameter (-integrin overexpression).