Abstract:
An imaging temperature sensing system having at least one imaging component and at least one temperature sensing component, thus providing means for implementing temperature sensing and imaging within a single device.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of provisional application Ser. No. 61/056,872 filed May 29, 2008 entitled OPTICAL FIBER THERMOMETER WITH IMAGING and which provisional application is incorporated herein in its entirety. 
    
    
     BACKGROUND 
     Various embodiments of this invention relate generally to endoscopic medical examination or surgery, as well as temperature sensing or mapping in medical applications. 
     Past endoscopic medical procedures involve a flexible conduit capable of relaying images that is inserted into a patient&#39;s body. Other tools may also be inserted to measure parameters such as temperature or to perform surgery. Specifically, fiber-optic temperature sensors employed for medical applications are typically inserted into a patient and guided to a particular location using an x-ray or other imaging system, thus providing a limited two-dimensional view. Alternatively, an endoscope may be used to aid in directing and positioning a sensing tip of a fiber optic thermometer within a patient&#39;s body. However, this process involves two separate components so that the endoscope may have to be re-positioned and re-oriented when the fiber is moved. It also involves having to manipulate at least two different instruments (endoscope and fiber thermometer). 
     It is therefore a need to develop a single endoscope-like instrument capable of imaging and temperature measurement within a patient&#39;s body. 
     SUMMARY 
     The needs for the invention set forth above as well as further and other needs and advantages of the present invention are achieved by the embodiments of the invention described herein below. 
     Various embodiments of this invention allow the addition of a view-port at the sensing element of a fiber-optic thermometer, which allows for more precise location of a sensing tip of the fiber-optic thermometer. Furthermore, it also allows for a visual inspection of the area within a body where the temperature is to be monitored, which can be an additional diagnostic during medical treatments including, but not limited to, microwave treatment for certain types of cancer. 
     Features of a fiber-optic endoscope and a fiber-optic thermometer may be incorporated in a single, compact device. Two principle technologies are involved. One technology is the temperature-dependent fluorescent-decay of an atomic resonance. Measurements are based upon the temperature-dependent fluorescence-decay process of a phosphor bonded to the end of an optical fiber, which constitutes the temperature probe. 
     The other technology is fiber-optic imaging. Multiple fibers may be arranged to form a composite optical fiber with an effectively larger diameter. The cross-section of an individual fiber may be on the order of a few microns in diameter, with an inner core of slightly higher optical index of refraction relative to the surrounding cladding layer. In contrast, the overall diameter of the composite fiber bundle may typically be on the order of a few hundred microns. A lens may be used to image an object onto one end of the fiber bundle. The light from the object that enters a given individual fiber will be transmitted to the opposite end of the bundle by total internal reflection of light rays within that individual fiber (alternatively, the light propagates within the optical fiber waveguide structure). If the relative arrangement of the fibers within the cross-section of the fiber bundle is maintained along its length, then the image of the object is transmitted to the other end of the bundle in a pixel format. 
     For a better understanding of the present invention, together with other and further needs thereof, reference is made to the accompanying drawings and detailed description and its scope will be pointed out in the appended claims 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram illustration of a temperature-dependent fluorescence-decay temperature sensor; 
         FIG. 2  is a schematic block diagram illustration of an optical fiber bundle for imaging; 
         FIG. 3  is a schematic block diagram illustration of a fiber-optic temperature sensor with a separate imaging fiber bundle; and 
         FIG. 4  is a schematic block diagram illustration of a fiber-optic temperature sensor with a shared imaging fiber bundle. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments of this invention allow for substantially simultaneous measurement of temperature of a surface and visual observation of the surface via optical fibers. A fiber-optic temperature sensor may utilize, for example, but not be limited to, temperature-dependent fluorescence-decay of an atomic resonance to measure temperature. In the example shown in  FIG. 1 , temperature sensor  5  includes a temperature-sensing component  10  in the form of, but not limited to, a phosphor, which exhibits temperature-dependent fluorescence-decay. The temperature-sensing component  10  is attached, for example, by, but not limited to, gluing, to substantially the end of an optical fiber  20 . In this embodiment, excitation electromagnetic radiation  30  such as, but not limited to, light in the form of optical pulses from a device such as, but not limited to, a low-power, broadband light-emitting diode (LED) source  40  propagates along the fiber  20  to the phosphor material or temperature-sensing component  10 . The phosphor absorbs the optical energy from the optical pulses  30  at the excitation wavelength and spontaneously emits fluorescence emission light  50  at a fluorescence wavelength. A portion of the fluorescence emission light  50  is captured by the optical fiber  20  and propagates in the optical fiber  20  back toward optics  60  such as, but not limited to, beamsplitters, gratings, or waveguide directional couplers, where it is separated from the path of the excitation electromagnetic radiation  30  by the optics  60  and directed to detector, such as, but not limited to, an optical detector  70 . 
     While the excitation electromagnetic radiation (light pulse)  30  is present at the temperature-sensing component (phosphor)  10 , the fluorescence emission light  50  slowly increases toward a maximum value. After the excitation electromagnetic radiation (light pulse)  30  is switched off, the fluorescence emission light  50  then begins to decay (decrease in power of signal). A higher temperature typically yields a faster decay process. A conventional calibration procedure is used in, but not limited to, a data processor  80  to correlate the temporal decay process with temperature of the temperature-sensing component (phosphor)  10 . 
     An example, not limiting the present embodiments, is a system for imaging with fiber optics is presented schematically in  FIG. 2 . An imaging system  95  may employ a lens  100 , which is used to image an object  110  via a fiber bundle  130 . Light  140  from the object  110  propagates through the lens and onto a first endface  120  of the fiber bundle  130  where a portion of the light  140  enters individual fibers  150  comprising the fiber bundle  130 , and subsequently propagates to a second endface  160  of the fiber bundle  130 , forming an image  170  of the object  110 . 
     In the embodiment illustrated schematically in  FIG. 3 , an imaging temperature sensor  195  includes a temperature-sensing optical fiber  200  and an imaging optical fiber bundle  210  arranged and fixed, for example, but not limited to, substantially adjacent relative to each other. Electromagnetic radiation, such as, but not limited to, light  220  for imaging is generated from a source  230  such as, but not limited to, a light emitting diode (LED) and directed to the optical fiber bundle  210  by imaging optics  240  such as, but not limited to, beamsplitters, gratings, or waveguide directional couplers, propagates through the optical fiber bundle  210 , and encounters an object  250  via a lens  260 . The light  220  is reflected from the object  250  and through the lens  260  back to the optical fiber bundle  210 . The light  220  returning through the optical fiber bundle  210  is separated by the imaging optics  240  and directed to a detector  270  such as, but not limited to, a CCD array or a camera, where it may be digitized. 
     Excitation electromagnetic radiation such as, but not limited to, light  280  for a phosphor or temperature-sensing component  290  located at an end of the temperature-sensing optical fiber  200  is generated by, but not limited to, a light source  300  such as, but not limited to, a LED and directed by optics  310  such as, but not limited to, beamsplitters, gratings, or waveguide directional couplers, through the temperature-sensing optical fiber  200 . Fluorescent light  320  from the phosphor tip  290  propagates through the temperature-sensing optical fiber  200  and is subsequently directed by the optics  310  to a detector  330  such as, but not limited to, a diode detector. 
     Temporal decay characteristics (such as a time constant for the temporal decay) may be measured by a data processor  340 , which may also be used for image processing the output of the camera  270 . An outer frame or housing  350 , which may be flexible, can be, but is not required to be, used to contain the two optical fibers. 
     Another embodiment of an imaging temperature sensor  395  is presented in  FIG. 4 , in which the temperature sensing and imaging functions are both provided via an optical fiber bundle  400 . Electromagnetic radiation such as, but not limited to, light  410  for imaging is generated from a source  420  such as, but not limited to, a light emitting diode (LED) and directed to the optical fiber bundle  400  by imaging optics  430  such as, but not limited to, beamsplitters, gratings, or waveguide directional couplers, propagates through the optical fiber bundle  400 , and encounters an object  440  via a lens  450 . The light  410  is reflected from the object  440  and through the lens  450  back to the optical fiber bundle  400 . The light  410  returning through the optical fiber bundle  400  is separated by the imaging optics  430  and directed to a camera  460  such as, but not limited to, a CCD array, where it may be digitized. 
     Excitation electromagnetic radiation such as, but not limited to, light  470  for a phosphor or temperature-sensing component  480  located at an end of the optical fiber bundle  400  is generated by a light source  490  such as, but not limited to, a LED and directed by optics  500  such as, but not limited to, beamsplitters, gratings, or waveguide directional couplers, through the optical fiber bundle  400 . Fluorescent light  510  from the phosphor tip  480  propagates through the optical fiber bundle  400  and is subsequently directed by the optics  500  to a detector  520  such as, but not limited to, a diode detector. Some or all of the fibers comprising the optical fiber bundle  400  may propagate a portion or substantially all of, one, or both, of the light  410  and the light  470 . 
     Temporal decay characteristics (such as a time constant for the temporal decay) may be measured by a data processor  530 , which may also be used for image processing the output of the detector in the form of, but not limited to, camera or CCD array  460 . 
     Thus, an imaging temperature sensor may include, for example, but not limited to, a fiber optic bundle for imaging and one or more fiber optic cables for temperature sensing. Imaging wavelengths may be kept separate from temperature sensing wavelengths so that means can be used for keeping them separate and improving data quality for both functions. 
     One use of the imaging temperature sensing system may be in the form of a medical application, but is not limited thereto, monitoring temperatures at various locations within the body of a patient undergoing an endoscopic examination or treatment. The imaging temperature sensing system of  FIG. 4 , for example, could provide temperature information for the location being imaged within the body of the patient providing additional diagnostic data. In this embodiment, the imaging temperature sensing system could be in the general form of an endoscope that is manipulated by medical personnel to position one end of the device within the body of the patient. 
     Although the invention has been described with respect to various embodiments, it should be realized this invention is also capable of a wide variety of further and other embodiments within the spirit and scope of the appended claims.