Fluorescence-mediated molecular tomography

A near-infrared, fluorescence-mediated molecular tomography imaging system comprising

• a near-infrared light source to provide incident light;
• a multipoint incident illumination array for directing light into an object from two or more separate excitation points;
• multiple optic fibers to transmit light from the light source to each point in the multipoint incident illumination array;
• a multipoint detection array to collect light emitted from the object from two or more separate collection points;
• a two-dimensional emitted light array to transmit light emitted from the object to a detector;
• multiple optic fibers to transmit light from each collection point to a corresponding point on the two-dimensional emitted light array;
• a detector to detect and convert light emitted from each point of the two-dimensional emitted light array into a digital signal representing the light emitted from the object;
• and
• a processor that processes the digital signal representing the light emitted from the object into a tomographic image of a target region within an object on an output device,
• wherein the processor is programmed to process the digital signal derived from light emitted from an object by
• i) generating a self-calibrated measurement M=M1−M3/M2−M4, wherein M1 is an emission wavelength fluorescence signal, M2 is an intrinsic signal, M3 is a background bleed-through signal, M4 is a background ambient light signal;
• ii) generating a self-calibrated intrinsic measurement M′=log (M2−M4)/(M5−M4), wherein M5 is a background-medium diffuse signal;
• iii) minimizing a function F(U)=(M−P×U)2 to obtain a distribution and magnitude of U, wherein U is a vector of unknown concentration of a target in the object being imaged and P is a forward predictor of M calculated by solving a diffusion equation for an appropriate geometry and background medium in fluorescence mode;
• iv) minimizing a function F′(O)=(M′−P′×O)2 to obtain a distribution and magnitude of O;
• wherein O is a vector of unknown concentration of a fluorophore in the object, and P′ is a forward predictor of M′ calculated by solving a diffusion equation for the appropriate geometry and background medium in absorption/scattering mode;
• v) calculating an activation ratio AR=U/O;
• and
• vi) generating an image corresponding to AR.

A method for obtaining an optical activation molecular map, the method comprising:

• i) administering to an object a molecular probe that comprises a near-infrared fluorophore;
• ii) obtaining a first data set of fluorophore concentration based on intrinsic absorption;
• iii) obtaining a second data set of activated fluorophore concentration based on fluorescence;
• iv) dividing the first data set by the second data set on a point-by-point basis to generate a third data set;
• and
• v) processing the third data set to provide an optical activation molecular map corresponding to a ratio of concentration of activated molecular probe to total concentration of molecular probe corresponding to molecular activity in the object.

A method of obtaining a three-dimensional, quantitative, molecular tomographic image of a target region within an object, the method comprising

• administering to the object a molecular probe that comprises a near-infrared fluorophore;
• directing near-infrared light from multiple points into the object;
• detecting fluorescent light emitted from multiple points from the object;
• and
• processing the detected light to provide a three-dimensional image that corresponds to a three-dimensional target region within the object.

A method of obtaining a three-dimensional, quantitative, molecular tomographic image of a target region within an object, the method comprising

• administering to the object a molecular probe that comprises a near-infrared fluorophore;
• directing near-infrared light from multiple points into the object;
• detecting fluorescent light emitted from multiple points from the object;
• and
• processing the detected light to provide a three-dimensional image that corresponds to the three-dimensional target region within the object,
• wherein processing comprises
• i) providing a first data set of fluorophore concentration based on intrinsic absorption;
• ii) providing a second data set of activated fluorophore concentration based on fluorescence;
• iii) dividing the first data set by the second data set on a point-by-point basis to provide a third data set;
• and
• iv) processing the third data set to provide an optical molecular map corresponding to a ratio of a concentration of a molecular probe to a concentration of a fluorophore corresponding to a target in the object.

A method of obtaining a three-dimensional, quantitative, molecular tomographic image of a target region within an object, the method comprising,

• administering to the object a molecular probe that comprises a near-infrared fluorophore;
• directing near-infrared light from multiple points into the object;
• detecting fluorescent light emitted from multiple points from the object;
• and
• processing the detected light to provide a three-dimensional image that corresponds to the three-dimensional target region within the object and to the quantity of molecular probe in the target region;
• wherein the processing comprises digitizing the fluorescent signal emitted from the object, self-calibrating the digital signal by combining fluorescent and intrinsic signal measurements from the object and background medium, and reconstructing a three-dimensional image that represents the quantity of molecular probe in the target region.