Patent Publication Number: US-2006020212-A1

Title: Portable vein locating device

Description:
FIELD OF THE INVENTION  
      The present invention relates to medical care. More particularly, the invention relates to a portable vein locating device for aiding a medical care giver in locating a vein through the skin of a patient, especially an obese patient or a patient with dark skin color.  
     BACKGROUND OF THE INVENTION  
      In the case of an obese and/or dark skinned patient, it is often very difficult for a medical caregiver to locate a vein beneath the patient&#39;s skin. To this end, various devices have been proposed for facilitating vein location. In particular, a number of devices have been proposed for illuminating the patient&#39;s skin with ambient visible light or an infrared light source and viewing the result through a camera. Unfortunately, such previously proposed devices are generally bulky and expensive in implementation. Additionally, such devices suffer from reduced contrast due to surface reflection and are sensitive to the ambient lighting conditions.  
      With the deficiencies of the prior art in mind, it is an overriding object of the present invention to improve of the prior art by providing a method utilizing a small and inexpensive device for locating beneath a patient&#39;s skin of a vein. Additionally, it is an object of the present invention to provide such a device that provides high resolution and is not sensitive to ambient lighting conditions.  
     SUMMARY OF THE INVENTION  
      In accordance with the foregoing objects, the present invention—a portable vein locating device—generally comprises one or more infrared illuminators for transmission through a patient&#39;s skin of infrared light and a vein imaging module for determining the location of a vein beneath the skin by detecting the absence of backscattered infrared light. The portable vein locating device is utilized by gently caressing a patient&#39;s skin in the area in which a vein is to be located with the portion of the device containing the infrared illuminators and vein imaging module. As the device is passed over the skin, infrared light from the infrared illuminators will penetrate through the patient&#39;s skin and be generally absorbed by veins under the skin but scattered by the fat and other tissues surrounding the veins, which tissues are very translucent and structured in nature. Backscattered infrared light from the areas about the veins is then detected by the vein imaging module, which includes a plurality of infrared light detectors, for detecting the backscattered light, and a display, for indicating to the medical caregiver the location beneath the skin of detected veins.  
      Finally, many other features, objects and advantages of the present invention will be apparent to those of ordinary skill in the relevant arts, especially in light of the foregoing discussions and the following drawings, exemplary detailed description and appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Although the scope of the present invention is much broader than any particular embodiment, a detailed description of the preferred embodiment follows together with illustrative figures, wherein like reference numerals refer to like components, and wherein:  
       FIG. 1  shows, in a perspective view, the preferred embodiment—a generally ink pen-sized locating stick—of the portable vein locating device of the present invention;  
       FIG. 2  shows, in a perspective view, details of the infrared illuminators and vein imaging module as contained within the locating stick of  FIG. 1 ;  
       FIG. 3  shows, in a cross-sectional view taken along cut line  3 - 3  of  FIG. 1 , various details of the infrared illuminators and imaging module depicted in  FIG. 2 ;  
       FIG. 4  shows, in a perspective view, an alternate embodiment—a locating box—of the portable vein locating device of the present invention;  
       FIG. 5  shows, in a partially cutaway perspective view corresponding to  FIG. 4 , details of the infrared illuminators and camera as contained within the locating box of  FIG. 4 ;  
       FIG. 6  shows, in a cross-sectional view taken along cut line  6 - 6  of  FIG. 4 , various details of the camera depicted in  FIG. 5  and associated imaging components;  
       FIG. 7  shows, in a cross-sectional view taken along cut line  7 - 7  of  FIG. 4 , various details of the infrared illuminators depicted in  FIG. 5 ; and  
       FIG. 8  shows, in a cross-sectional view taken along cut line  8 - 8  of  FIG. 4 , various details of the infrared illuminators and camera as depicted in  FIG. 5 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Although those of ordinary skill in the art will readily recognize many alternative embodiments, especially in light of the illustrations provided herein, this detailed description is exemplary of the preferred embodiment of the present invention, the scope of which is limited only by the claims appended hereto.  
      As shown in  FIGS. 1 through 3 , the portable vein locating device  10  of the present invention preferably comprises an ink pen-sized locating stick  11  having integrated therein one or more infrared illuminators  12  and a vein imaging module  17 . As will be better understood further herein, the portable vein locating device  10  is utilized by gently caressing a patient&#39;s skin in the area in which a vein is to be located with the end of the locating stick  11  containing the infrared illuminators  12  and vein imaging module  17 . Infrared light from the infrared illuminators  12  will penetrate through the patient&#39;s skin and be generally absorbed by veins under the skin but scattered by the fat and other tissues surrounding the veins, which tissues are very translucent and structured in nature. Backscattered infrared light from the areas about the veins is then detected by the vein imaging module  17 , which includes a plurality of infrared light detectors  18 , for detecting the backscattered light, and a display  19 , for indicating to the medical caregiver the location beneath the skin of detected veins.  
      As shown in the figures, the infrared illuminators  12  of the locating stick  11  preferably each comprise an infrared light emitting diode (“LED”)  13  mated with a diffusing light guide  14 . As will be appreciated by those of ordinary skill in the art, such a diffusing light guide  14  may be implemented by doping an optical material with aluminum powder or other dopants as is widely known in the manufacture of cellular telephone backlighting systems, television remote controls and the like. As also will be appreciated by those of ordinary skill in the art, the light guide  14  is manufactured with most sides  15  provided with a reflective coating and the sides  16  adjacent the infrared LED  13  and to be placed adjacent the patient&#39;s skin being substantially transparent to infrared light. In this manner, infrared light from the infrared LED  13  may directed through the patient&#39;s skin.  
      As also shown in the figures, the infrared light detectors  18  of the locating stick  18  are arranged in a generally linear array. Likewise, a plurality of LEDs  20 , which form the display  19 , are also arranged as a generally linear array corresponding to that of the light detectors  18 , which, as will be appreciated by those of ordinary skill in the art, may comprise any of a variety of infrared sensitive optical sensors such as, for example, a charge coupled device (“CCD”) sensor array, a complementary metal oxide semiconductor (“CMOS”) sensor array, a phototransistor sensor array or the like. In any case, the LEDs  20  of the display  19  light to indicate the presence under the skin of a vein as detected by the elements of the infrared light detectors  18 . As will be appreciated by those of ordinary skill in the art, an LED driver circuit  21 , which is readily within the reach of those of ordinary skill in the art, is implemented to preferably light the LEDs  20  over the light detectors  18  that do not receive backscattered infrared light, thereby giving an intuitive indication of the location beneath the locating stick  11  of a vein.  
      Referring now to  FIGS. 4 through 8 , an alternate embodiment of the portable vein locating device  10  is shown wherein the device  10  is implemented with a locating box  24 , generally more bulky than the locating stick  11 , but including a two dimensional liquid crystal display (“LCD”)  32  for increased display of a detected vein and a plurality of infrared LEDs  26  for increased transmission through the skin of infrared light. As shown in the figures, one or more infrared illuminators  25  is provided for transmission of infrared light through the person&#39;s skin where the infrared light is either absorbed by veins or partially backscattered as previously discussed. In the case of the locating box  24 , however, backscattered infrared light is passed through a generally translucent imaging window  31  through the central portion of the base of the box  24  and imaged by a provided camera  29 , which may be implemented using well known CCD technology or the like. To facilitate imaging, a mirror  30  may be positioned within the locating box  24  as particularly shown in  FIGS. 5 through 7 . In any case, the image through the translucent window  31  as captured by the camera  29  is displayed on the LCD  32  identifying for the medical caregiver the precise layout of veins located beneath the patient&#39;s skin. As will be appreciated by those of ordinary skill in the art, appropriate electronic circuitry (well within the level of ordinary skill in the art) is provided for operation of the camera  29  and display on the LCD  32  of the acquired image.  
      In the implementation comprising the locating box  24 , the infrared illuminators  35  may comprise a plurality of LEDs  26  positioned within the locating box  24  and oriented to transmit infrared light through windows  28  through the outer portions of the base of the box  24 . To facilitate light transmission, a plurality of mirrors  27  or mirrored surfaces may be provided adjacent to the LEDs  26  and the windows  28 .  
      While the foregoing description is exemplary of the preferred embodiment of the present invention, those of ordinary skill in the relevant arts will recognize the many variations, alterations, modifications, substitutions and the like as are readily possible, especially in light of this description, the accompanying drawings and claims drawn thereto. For example, the generally ink pen-shaped protective case  22  of the locating stick  11  of the preferred embodiment of the present invention may be provided with an ink pen-style pocket clip  23  or the like for convenient carrying by a medical caregiver.  
      Likewise, those of ordinary skill in the art will recognize that appropriate circuitry may be implemented to modulate the infrared light passed through the skin at a predetermined frequency and to perform a synchronized signal amplification of the detected signal. In this manner, very high imaging quality may be obtained and the device may be readily utilized even in bright sunlight. In any case, because the scope of the present invention is much broader than any particular embodiment, the foregoing detailed description should not be construed as a limitation of the scope of the present invention, which is limited only by the claims appended hereto.