Characterizing a Photoacoustic and Fluorescence Imaging Platform for Preclinical Murine Longitudinal Studies

Significance: 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. Aim: We introduce and characterize a dual-modality PA and FL imaging platform using in vivo and phantom experiments. Approach: 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. Results: The system characterization yielded a PA spatial resolution of 173 +/- 17 mu m in the transverse plane and 640 +/- 120 mu m in the longitudinal axis, a PA sensitivity detection limit not less than that of a sample with absorption coefficient mu(a) 1/4 0.258 cm(-1), an optical spatial resolution of 70 mu m in the vertical axis and 112 mu m in the horizontal axis, and a FL sensitivity detection limit not <0.9 mu M concentration of IR-800. The scanned animals displayed in threedimensional renders showed high-resolution anatomical detail of organs. Conclusions: 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.(c) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 International License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.