Method and system for near-infrared fluorescence contrast-enhanced imaging with area illumination and area detection

Inventors

Sevick-Muraca, Eva M. • Thompson, Alan B. • Ranadhir, Roy

Assignees

Texas A&M University System • Texas A&M University

Abstract

According to one embodiment of the invention, a method for biomedical imaging includes directing time-varying excitation light at a surface area of a light scattering material, the material comprising a fluorescent target. Time-varying emission light from the fluorescent target is detected, substantially at a two-dimensional sensor surface, in response to the time-varying excitation light stimulating the fluorescent target. The time-varying emission light is filtered to reject excitation light re-emitted from the material. A three-dimensional image of the fluorescent target is generated based on the detection substantially at the sensor surface.

Core Innovation

The invention provides a method and system for near-infrared fluorescence contrast-enhanced biomedical imaging using area illumination and area detection. Time-varying excitation light is directed at a surface area of a light scattering material or tissue containing a fluorescent target. Emission light stimulated by this excitation is detected substantially at a two-dimensional sensor surface. The detected emission light is filtered to reject excitation light re-emitted from the material, and a three-dimensional image of the fluorescent target is generated based on these detections.

The problem addressed arises from prior art methods that use point illumination and point detection with fiber optics, which may fail to sufficiently excite fluorescent targets and produce sparse data sets, making the inverse problem of image reconstruction challenging. The invention overcomes these disadvantages by employing area illumination and area detection on the same tissue-like surface, leading to more efficient excitation of fluorophores within a large tissue volume and significantly more data, thereby improving imaging accuracy.

The method further includes determining the spatial distribution of amplitude and phase-delay of both the emission light and the incident excitation light. The incident excitation light distribution is experimentally determined using polarization techniques to separate specularly reflected excitation light from multiply scattered light, facilitating accurate modeling of light propagation. Mathematical reconstruction of a 3D image uses a modified barrier penalty function optimizing fluorescence absorption coefficients based on coupled frequency-domain diffusion equations solved with finite element methods.

Claims Coverage

The claims include two independent method claims and one independent system claim, each comprising inventive features related to near-infrared fluorescence imaging with area illumination and area detection, modulation techniques, filtering, and image reconstruction.

The claims cover methods and systems that utilize time-varying, intensity-modulated excitation light over a surface area, area detection of emission light on a two-dimensional sensor, filtering techniques to reject excitation light, determination of spatial amplitude and phase-delay of both excitation and emission light, and generation of three-dimensional images of fluorescent targets. The invention includes modulation at radio frequency, polarization methods to separate excitation light components, and system components configured to perform these functions.

Stated Advantages

Documented Applications