BACKGROUND OF THE INVENTION

Field of the Invention

The present matter relates generally to an optical imaging device and, more specifically, to a miniaturized optical imaging device for in vitro or in vivo imaging.

Description of the Related Art

Throughout the years, the need for imaging biological tissue in vivo for applications ranging from neuronal imaging to imaging cells to differentiate cancer cells from normal cells has increased. Various optical imaging devices exist for these purposes, examples of which are a miniature free space microscope for fluorescence imaging of neurons in a live, freely moving mammal, and example of which is shown inFIG. 1. A device such as this is described inMiniaturized Integration of a Fluorescence Microscope, Kunal K. Ghosh et al., Nature Methods, Vol. 8 No. 10, October 2011, p. 871, which is incorporated herein by reference. This device uses a graded index lens121(known as a GRIN lens) to both illuminate and collect light from the object. A light emitting diode (LED)160is used to illuminate the object, while a lens153couples the LED light into the GRIN lens121. An illumination filter155and an emission filter170make sure the light that arrives at the detector180is only the light that fluoresced from the object. A lens141completes the imaging onto the detector180. Both LED160and detector's electronics190are powered by connections163and191to external DC voltage supplies and the detector also transmits images to a computer using a wire connection191.

Another type of device, as described, for example, inUltra-compact Fiber-optic Two-photon Microscope for Functional Fluorescence Imaging in vivo, Christoph J. Engelbrecht et al., Optics Express, Vol. 16, Issue 8, pp. 5556-5564 (2008) and inVisually Evoked Activity in Cortical Cells Imaged in Freely Moving Animals, Juergen Sawinski et al., PNAS, Nov. 17, 2009, vol. 106, No. 46, pp. 19557-19562, allows multi-photon absorption imaging in a freely moving mammal.

Yet, another example, as described inNeuron50, 617-629, May 18, 2006, Elsevier Inc., uses a coherent fiber bundle for in vivo fluorescence imaging of a small mammal, as the mammal moves around freely.

Various imaging techniques using an optical fiber are summarized inFiber-optic Fluorescence Imaging, Benjamin A Flusberg, Eric D Cocker, Wibool Piyawattanametha et al., Nature Methods, Vol. 2 No. 12, December 2005. Other examples exist of various optical imaging devices and modalities that are used for biological imaging.

SUMMARY OF THE INVENTION

In accordance with the present invention, a multiple target optical imaging apparatus is provided that performs optical imaging of a plurality of physically-separated imaging sites. The apparatus includes at least one light source for illuminating the imaging sites, and a two-dimensional detector. A plurality of fiber bundles each have a proximal end and a distal end, such that the distal end of each bundle is positioned adjacent to a different one of the imaging sites. Each fiber bundle conveys light generated by the light source from the proximal end to the distal end of the bundle, and each conveys an optical signal from a respective imaging site from its distal end to its proximal end.

In one embodiment of the invention, the optical signal from each fiber bundle is directed to a different spatial region of a detection surface of the detector. The detector may also be configured such that it detects all of the optical signals simultaneously. In a particular application, the plurality of imaging sites includes different imaging locations on a biological subject, such as an animal. The different imaging sites may correspond to a plurality of different biological systems of the animal, which may be conscious and ambulatory. To adapt the system to the animal, the light source and detector may be located in a portable housing attached to the animal's body. Batteries may be used as a power source for the system, and a wireless transceiver can be used to communicate data collected by the detector to a remote location.

Different variations of the invention may also have features that adapt it to a specific application. For example, at least one of the fiber bundles may include a magnification element that provides magnification of the optical signal received from the respective imaging site for that bundle. In another embodiment, a wavelength dispersive element may be used that separates the optical signal from at least one of the fiber bundles into discrete wavelength ranges. In a different embodiment, the system may use a polarization-dependent filter that filters the optical signal of at least one of the fiber bundles. In yet another embodiment, the optical signal of at least one of the fiber bundles is a fluorescence signal.

Depending on the configuration of the light source, detector and fiber bundles, as well as the specific application in question, different components may be used for controlling the light entering and exiting each of the fiber bundles. For example, a dichroic mirror may be used to provide separation of light from the light source from the optical signal from one or more of the imaging sites. Similarly, a beamsplitter may be used to provide wavelength-independent separation of the light from the light source and/or one or more of the optical signals. Lenses may also be used in different positions in the system to allow proper focusing and/or collimation of light entering or exiting the fiber bundles, or being directed from the light source or toward the detector. A plurality of such lenses may also be used, with each lens being associated with one of the fiber bundles.

