System and method useful for sarcomere imaging via objective-based microscopy

Abstract

Biological tissue such as skeletal and cardiac muscle can be imaged by using an objective-based probe in the tissue and scanning at a sufficiently fast rate to mitigate motion artifacts due to physiological motion. According to one example embodiment, such a probe is part of a system that is capable of reverse-direction high-resolution imaging without needing to stain or otherwise introduce a foreign element used to generate or otherwise increase the sensed light. The probe can include a light generator for generating light pulses that are directed towards structures located within the thick tissue. The system can additionally include aspects that lessen adverse image-quality degradation. Further, the system can additionally be constructed as a hand-held device.

What is claimed is: 
     
         1 . A method for analyzing a biological tissue of a subject, comprising:
 (a) providing at least one light source in optical communication with said biological tissue;   (b) using said at least one light source to deliver light pulses to said biological tissue to cause one or more signals intrinsic to a property of said biological tissue to be generated, wherein during delivery of said light pulses to said biological tissue, an optical unit comprising an afocal lens arrangement shifts a focal plane of said light pulses in said biological tissue; and   (c) collecting at least a subset of said one or more signals intrinsic to said property of said biological tissue.   
     
     
         2 . The method of  claim 1 , further comprising using a scanning mirror to provide line scanning of said light pulses. 
     
     
         3 . The method of  claim 2 , wherein said afocal lens arrangement is disposed between said at least one light source and said scanning mirror. 
     
     
         4 . The method of  claim 1 , wherein said afocal lens arrangement is disposed between said at least one light source and an optical probe that focuses said light pulses. 
     
     
         5 . The method of  claim 4 , further comprising maintaining a resolution of said one or more signals during focal plane changes by providing light pulses that overfill a back aperture of said optical probe. 
     
     
         6 . The method of  claim 4 , wherein said optical probe comprises an objective, and wherein said objective focuses said light pulses at said biological tissue. 
     
     
         7 . The method of  claim 6 , wherein said objective is telecentric. 
     
     
         8 . The method of  claim 6 , wherein said objective provides substantially constant magnification of said light pulses during focal plane changes. 
     
     
         9 . The method of  claim 6 , wherein said objective is not translated for focusing said light pulses. 
     
     
         10 . The method of  claim 1 , wherein said afocal lens arrangement maintains constant power of said light pulses generated from said at least one light source to maintain a maximum resolution of said light pulses. 
     
     
         11 . The method of  claim 1 , wherein said afocal lens arrangement comprises a mobile lens that shifts said focal plane in said biological tissue. 
     
     
         12 . The method of  claim 11 , wherein said afocal lens arrangement further comprises a fixed lens that maintains a substantially constant beam waist of said light pulses leaving said afocal lens arrangement. 
     
     
         13 . The method of  claim 12 , wherein a scanning mirror is disposed in a focal plane of said fixed lens, and wherein said scanning mirror provides line scanning of said light pulses. 
     
     
         14 . The method of  claim 1 , wherein said afocal lens arrangement provides convergence or divergence to said light pulses, thereby shifting said focal plane in said biological tissue. 
     
     
         15 . The method of  claim 1 , further comprising using said at least subset of said one or more signals to generate an image of said biological tissue. 
     
     
         16 . The method of  claim 1 , wherein said one or more signals comprise second-harmonic generation signals (SHG) or autofluorescence signals. 
     
     
         17 . The method of  claim 16 , further comprising using said SHG or autofluorescence signals to generate an image of said biological tissue. 
     
     
         18 . A method for analyzing a biological tissue of a subject, comprising:
 (a) providing at least one light source in optical communication with said biological tissue;   (b) using said at least one light source to deliver light pulses to said biological tissue to cause one or more signals intrinsic to a property of said biological tissue to be generated, wherein said light pulses are delivered to said biological tissue at a line resolution rate sufficient to reduce motion artifacts; and   (c) collecting at least a subset of said one or more signals intrinsic to said property of said biological tissue.   
     
     
         19 . The method of  claim 18 , wherein said one or more signals comprise second-harmonic generation signals (SHG) or autofluorescence signals. 
     
     
         20 . The method of  claim 18 , wherein said line resolution rate is at least about 1 kiloHertz (kHz).