In vivo optical imaging of acute myeloid leukemia by green fluorescent protein: time-domain autofluorescence decoupling, fluorophore quantification, and localization.

Human xenografts of acute myeloid leukemia (AML) in nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice result in disease states of diffuse, nonpalpable tissue infiltrates exhibiting a variable disease course, with some animals not developing a disease phenotype. Thus, disease staging and, more critically, quantification of preclinical therapeutic effect in these models are particularly difficult. In this study, we present the generation of a green fluorescent protein (GFP)-labeled human leukemic cell line, NB4, and validate the potential of a time-domain imager fitted with a 470 nm picosecond pulsed laser diode to decouple GFP fluorescence from autofluorescence on the basis of fluorescence lifetime and thus determine the depth and relative concentration of GFP inclusions in phantoms of homogeneous and heterogeneous optical properties.