System and method for identifying tissue using low-coherence interferometry

#1. Field of the Invention

#The present invention relates to an apparatus and method for identifying tissue types using interferometric ranging during needle biopsy. More particularly, the present invention relates to an imaging system including a needle probe and algorithms for detecting various tissue types during a biopsy. Also provided is a method for differentiating tissue types using the imaging system.

#2. Background of the Invention

#Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying figures showing illustrative embodiments of the invention, in which:

#FIG. 1A is a graph of LCI reflectivity for muscle tissue.

#FIG. 1B is a graph of LCI reflectivity for adipose tissue.

#Throughout the figures, the same reference numerals and characters, unless otherwise stated, are used to denote like features, elements, components or portions of the illustrated embodiments. Moreover, while the subject invention will now be described in detail with reference to the figures, it is done so in connection with the illustrative embodiments. It is intended that changes and modifications can be made to the described embodiments without departing from the true scope and spirit of the subject invention as defined by the appended claims.

#In accordance with the system of the present invention, FIG. 2 illustrates an tissue identification system 2 according to one embodiment of the present invention for tissue 10 identification using interferometric ranging. The tissue identification system 2 utilizes a one-dimensional data set in order to identify tissue. Unlike many prior art systems, which use two-dimensional data in order to acquire sufficient information to identify tissue, the tissue identification system 2 is able to identify tissue using a one-dimensional data set. Differences between two types of tissue may be understood from a one-dimensional data set. For example, FIG. 1 illustrates two graphs that represent a one-dimensional interferometric ranging axial scan of two different tissue types. As can be seen from these graphs, adipose tissue (shown in the bottom graph) has a significantly different axial reflectance profile as compared to the axial reflectance profile of muscle tissue (shown in the top graph). The tissue identification system 5 includes an imaging system 5 and a probe 50.

#The imaging system 5 includes a light source 12, which is provided in an interferometer 14. The interferometer 14 can be a fiber optic interferometer 14. Also, while light is used in the disclosure herein as an exemplary embodiment of the light source 12, it should be understood that other appropriate electromagnetic radiation can be used, such as, microwave, radio frequency, x-ray, and the like. The interferometer 14 or other beam splitting device known to those skilled in the art may make use of circulators for increased sample arm power efficiency. The interferometer 14 includes a beam splitter 18, a reference arm 20, a sample arm 24, and a communications link to at least one detector 26. The light source 12 is connected to the interferometer 14 such that the light emitted from the light source 12 is transmitted to the beam splitter 18. The beam splitter 18 directs portion of the light emitted by the source 12 towards a reference arm 20, while the remainder of light is directed to a sample arm 24. The reference arm 20 includes a mechanism 26. The mechanism 26 produces a time dependent optical delay. In a certain embodiment, the mechanism 26 can be a movable reference reflector or mirror. The movable reference reflector or mirror can create a variable time delay suitable for a specific application.