Patent ID: 7346387

Claim:
Imaging apparatus adapted for in vivo imaging a particular volume of plant or animal tissue containing at least one photo-active molecular agent, the apparatus comprising: a source of collimated light, said light having a frequency effective to penetrate substantially into the tissue, said light being adapted to promote simultaneous two-photon excitation (TPE) of the molecular agent contained within the tissue; beam expanding apparatus for expanding said collimated light into an expanded beam of collimated light; focusing apparatus for focusing the expanded beam of collimated light throughout a range of focal lengths extending from a surface of said tissue to a depth substantially beyond said surface, said light source and focusing apparatus cooperating to promote TPE of the molecular agent, wherein a focal point or focal plane is adjustable over a distance of up to 100 mm with respect to said tissue; a detector located proximate to the tissue and positioned to detect said light emitted by the molecular agent and which travels a path that does not retrace an optical path of the light incident on the tissue, said detector configured to produce a detected signal characteristic of the particular volume at which the light source has been focused; a processor coupled to said detector; and a modulation system associated with said light source, said processor being coupled to said modulation system and adapted to produce a demodulated energy signal which is characteristic of the particular photo-activated molecular agent.