Methods for improved selectivity in photo-activation and detection of molecular diagnostic agents

Apparatus adapted for in vivo medical diagnostic imaging comprising:

• light source means for directing a confined light at and into tissue to be imaged, said light being selected in frequency and energy to penetrate below a tissue surface and to promote TPE substantially only at a confocal region at a distance of up to 100 mm below said tissue surface, said light source means including beam expanding means and focusing means cooperating together to shape said confocal region;
• means for varying a position of a confocal region of the light within a range of depths in the tissue to be imaged;
• detector means positioned to receive and detect isotropic radiation emitted by a photo-activated molecular agent within the tissue after said agent has been excited using two-photon excitation;
• a modulator means for modulating said light with a type of modulation and producing a modulated light;
• and
• a processor coupled to said detector, said processor being coupled to said modulation system and adapted to produce a demodulated energy signal which is characteristic of said photo-activated molecular agent.

An apparatus adapted for in vivo microscopic imaging to a distance of up to 100 mm within tissue comprising:

• a light source, said light source producing a beam of light directed to or into a material to be imaged, wherein said light source includes beam expanding means and beam focusing means cooperating together to shape said beam of light into a confocal region, said light being selected in frequency and energy to penetrate into or below a surface of the material and to promote two-photon excitation substantially only in a confocal region to be imaged;
• a modulator, said modulator cooperating with said light source to modulate said light with a type of modulation and produce a modulated light;
• a detector positioned to receive and detect radiation emitted by a photo-activated molecular agent within the material after said agent has been excited using two-photon excitation;
• and
• a demodulator, said demodulator coupled to said detector and producing a demodulated energy signal which is characteristic of the particular photo-activated molecular agent.

Apparatus adapted to in vivo medical diagnostic imaging comprising:

• a light source, said light source producing light directed to or into deep tissue to be imaged, said light being selected in frequency and energy to penetrate into or below a surface of the tissue and to promote two-photon excitation substantially only in a region to be imaged;
• a beam expanding apparatus adapted for expanding said light into an expanded beam of light;
• a focusing apparatus adapted for focusing said expanded beam of light, said focusing apparatus being able to vary the position of the light within a range of depths in the region of tissue to be imaged, said range of depths extending up to 100 mm into said tissue to be imaged;
• and
• a detector positioned to receive and detect radiation emitted by a photo-activated molecular agent within the material after said agent has been excited using two-photon excitation,
• wherein said light source means includes means for producing a collimated light beam and focusing means for focusing the collimated light beam to a confocal region located with tissue at a point below the tissue surface.