Phantom and methodology for fluorescence molecular imaging systems benchmarking

A critical issue associated with the clinical translation of fluorescence molecular imaging relates to the reproducibility of the collected measurements. In particular, images acquired from the same target using different fluorescence cameras may vary considerably when the employed systems have markedly different specifications. Methods that standardize fluorescence imaging are therefore becoming necessary for assessing the performance of fluorescence systems and agents and for providing a reference to the data collected. In the work presented herein we propose a composite phantom for integrating multiple targets within the field of view of a fluorescence camera. Each quadrant of this phantom resolves different fluorescence features: (1) sensitivity as a function of the optical properties; (2) sensitivity as a function of the depth from the top surface; (3) resolution of the fluorescence and optical imaging; and (4) cross-talk from the excitation light. In addition, there exist structures in the phantom for assessing homogeneity of the incident illumination. In order to validate our main hypothesis that standardization of fluorescence imaging systems is feasible through imaging such a phantom, we employed two systems of different specifications and quantified all relevant performance metrics. The derived results showcase the feasibility of fluorescence cameras calibration. Additionally, we demonstrate a methodology of comparing fluorescence cameras by means of benchmarking scoring. We expect that such approaches will boost the clinical translation of fluorescence molecular imaging and will allow for the investigation of novel fluorescence agents.