Characterizing a photoacoustic and fluorescence imaging platform for preclinical murine longitudinal studies

To effectively study preclinical animal models, medical imaging technology must be developed with a high enough resolution and sensitivity to perform anatomical, functional, and molecular assessments. Photoacoustic (PA) tomography provides high resolution and specificity, and fluorescence (FL) molecular tomography provides high sensitivity; the combination of these imaging modes will enable a wide range of research applications to be studied in small animals.

We introduce and characterize a dual-modality PA and FL imaging platform using in vivo and phantom experiments.

The imaging platform's detection limits were characterized through phantom studies that determined the PA spatial resolution, PA sensitivity, optical spatial resolution, and FL sensitivity.

The system characterization yielded a PA spatial resolution of $$ in the transverse plane and $$ in the longitudinal axis, a PA sensitivity detection limit not less than that of a sample with absorption coefficient $$ , an optical spatial resolution of $$ in the vertical axis and $$ in the horizontal axis, and a FL sensitivity detection limit not $$ concentration of IR-800. The scanned animals displayed in three-dimensional renders showed high-resolution anatomical detail of organs.

The combined PA and FL imaging system has been characterized and has demonstrated its ability to image mice in vivo, proving its suitability for biomedical imaging research applications.