Imaging of light scattering tissues with fluorescent contrast agents

A method, comprising:

• evaluating ability of a number of fluorescent agents to provide image contrast between different tissue types, said evaluating including determining a relationship between degree of image contrast and at least one of fluorescence lifetime or fluorescence yield of the agent;
• selecting one of the agents based on said evaluating;
• and
• providing the selected one of the agents for introduction into a biologic tissue to enhance imaging performed in accordance with a mathematical expression modeling the behavior of multiply scattered light traveling through the tissue.

A method, comprising:

• exposing a biologic tissue to a first excitation light;
• detecting a first emission from the tissue in response to the first excitation light;
• introducing a fluorescent contrast agent into the tissue after said detecting;
• exposing the tissue after said introducing to a second excitation light;
• sensing a second emission in response to the second excitation light;
• comparing data corresponding to the first emission with data corresponding to the second emission to evaluate contrast provided by the agent as a function of at least one of fluorescence lifetime, fluorescence yield, or quantum efficiency.