Administration of aminolevulinic acid with delayed fluorescent imaging to map and quantify tissue oxygenation levels

A system for imaging oxygen concentration in diffuse media using a protoporphyrin IX probe comprising:

• a pulsed light source operable at an excitation wavelength of a protoporphyrin IX (PPIX) fluorophore in the diffuse media and configured to illuminate the diffuse media with light pulses;
• a gated electronic camera synchronized to the pulsed light source and configured to capture delayed fluorescence images of the diffuse media in at least one delayed fluorescence time window beginning after an end of a light pulse from the pulsed light source and not overlapping light pulses from the pulsed light source,
• the gated electronic camera further configured to capture immediate fluorescence images of the diffuse media in an immediate fluorescence time window overlapping pulses of light pulse from the pulsed light source;
• and
• an image processor coupled to receive the immediate fluorescent images and the delayed fluorescence images from the gated electronic camera, the image processor configured to produce images indicative of oxygenation of the diffuse media based upon at least the delayed fluorescence images;
• wherein the images indicative of oxygenation of the diffuse media comprise images representing ratios of the delayed fluorescence images to the immediate fluorescence images.

A system for imaging oxygen concentration in diffuse media using a protoporphyrin IX probe comprising:

• a pulsed light source operable at an excitation wavelength of a protoporphyrin IX (PPIX) fluorophore in the diffuse media and configured to illuminate the diffuse media with light pulses;
• a gated electronic camera synchronized to the pulsed light source and configured to capture delayed fluorescence images of the diffuse media in at least one delayed fluorescence time window beginning after an end of a light pulse from the pulsed light source and not overlapping light pulses from the pulsed light source,
• the gated electronic camera further configured to capture immediate fluorescence images of the diffuse media in an immediate fluorescence time window overlapping pulses of light pulse from the pulsed light source;
• and
• an image processor coupled to receive the immediate fluorescent images and the delayed fluorescence images from the gated electronic camera, the image processor configured to produce images indicative of oxygenation of the diffuse media based upon at least the delayed fluorescence images;
• wherein the pulsed light source comprises a structured-light modulator adaptable to provide a plurality of spatially modulated light patterns at a plurality of spatial frequencies and phase offsets, wherein the gated electronic camera is configured to obtain structured-light images of the diffuse media as illuminated by the spatially modulated light patterns and wherein the image processor is further configured to obtain extract optical parameters from the structured-light images.

A method of generating oxygen level map images of diffuse media, comprising:

• using an illuminator configured to provide pulses of fluorescence excitation light;
• obtaining an immediate fluorescence image of protoporphyrin IX (PPIX) in the diffuse media and a delayed fluorescence image of PPIX in the diffuse media with a gated camera, the immediate fluorescence image being obtained during pulses of fluorescence excitation light and the delayed fluorescence image being obtained after and not overlapping the pulses of fluorescence excitation light;
• and
• determining a ratio image from the delayed fluorescence image and the immediate fluorescence image, the ratio image processed to provide an oxygen level image of the diffuse media.