Abstract:
A method and apparatus for reducing damage to a phosphor imaging plate caused by physical interaction between the phosphor imaging plate and a surface by affixing a protective material to the surface to reduce the physical interaction between the phosphor imaging plate and the surface. Exemplary surfaces include without limitation the surfaces of a computed radiography scanner and a plate protector.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to phosphor imaging plates used in computer radiography, and more specifically, to reducing damage to phosphor imaging plates. 
         [0002]    In Computed Radiography (CR), a reusable phosphor imaging plate is used to capture images by scanning the phosphor imaging plate to read and digitize the image. The phosphor imaging plate, also referred to as a phosphor storage plate, contains a coating of photostimulable storage phosphors. This phosphor coating is protected from damage by a protective top coating. When exposed to X-rays, electrons inside the phosphors are excited and trapped in a semi-stable higher energy state. In order to retrieve the image, the phosphor imaging plate is scanned by a scanning laser beam, which causes the electrons to relax to a lower energy state causing visible light to be emitted. This visible light is captured and converted to a digital bit stream which encodes the digital image, which can be viewed and enhanced using software. When complete, the image on the phosphor imaging plate can be erased by exposing the photostimulable storage phosphors to fluorescent light, after which the phosphor imaging plate can be reused. Absent damage to the phosphor coating, this phosphor imaging plate can be reused several thousands of times. 
         [0003]    One source of damage to the phosphor coating is the physical interaction between the CR scanner and the phosphor imaging plate as the plate is fed and transported through the scanner. During scanning, scratches and abrasions to the protective top coating can result as the phosphor imaging plate slides along the surface of the scanner. Another source of damage to the phosphor coating is the physical interaction between a plate protector and the phosphor imaging plate. Given that an image on the phosphor imaging plate can be erased by exposing the photostimulable storage phosphors to fluorescent light, the phosphor imaging plate can be stored and carried in a envelope-like device that covers and shields the side of the phosphor imaging plate having the phosphor coating (i.e., the active side). As the phosphor imaging plate is inserted and removed from the plate protector, scratches and abrasions to the protective top coat can result as the phosphor imaging plate slides along the front surface of the plate protector. Given the frequency of use of the phosphor imaging plate in both a CR scanner and a protector plate, repeated damage to the protective top coating can eventually penetrate and also damage the phosphor coating. When this happens, the phosphor imaging plate must be replaced. 
         [0004]    It would therefore be advantageous to have a method and apparatus to reduce damage to phosphor imaging plates during use to prolong the life of the plates. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0005]    A method and apparatus for reducing damage to a phosphor imaging plate caused by physical interaction between the phosphor imaging plate and a surface by affixing a protective material to the surface to reduce the physical interaction between the phosphor imaging plate and the surface. Exemplary surfaces include without limitation the surfaces of a computed radiography scanner and a plate protector. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a top and bottom view of an exemplary phosphor imaging plate. 
           [0007]      FIG. 2  is a cross-section of an exemplary phosphor imaging plate. 
           [0008]      FIG. 3  is a top view of an exemplary plate protector. 
           [0009]      FIG. 4  is a perspective view of an exemplary CR scanner. 
           [0010]      FIG. 5  is a top view of an exemplary plate protector with protective material strips in one embodiment of the invention. 
           [0011]      FIG. 6  is a perspective view of an exemplary CR scanner with protective material strips in one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0012]      FIG. 1  depicts a top and bottom view of an exemplary phosphor imaging plate  10 , having an active side  12  (i.e., the side of the plate having the phosphor coating) and an inactive side (not shown).  FIG. 2  is a cross-section of an exemplary phosphor imaging plate  10  illustrating the different layers that typically compose the plate  10 . For example, starting from the active side  12 , there is top protective coating layer  20 , which protects the phosphor coating layer  22 , which in turn resides on an adhesion layer  24 . The phosphor imaging plate  10  also includes a support layer  26  and base outer coating  28  forming the inactive side  14  of the plate  10 . The purpose of the top protective coating layer  20  is to protect the phosphor coating layer  22  to extend the life of the phosphor imaging plate  10 . 
         [0013]      FIG. 3  depicts a top view of an exemplary plate protector  30  having a front surface  32  along with a first guide flap  34  and second guide flap  36  along its sides. The guide flaps  34 ,  36  allow for a phosphor imaging plate  10  to be inserted and slid into, and subsequently held, by the plate protector  30 . To facilitate insertion of the phosphor imaging plate  10 , the guide flaps  34 ,  36  can also include tabs  38 ,  40  bent upward from the front surface  32  to receive the phosphor imaging pate  10 . To protect the phosphor imaging plate  10  from being erased by fluorescent light, the phosphor imaging plate  10  is inserted and slid into the plate protector  30  below the guide flaps  34 ,  36  with the active side  12  facing and contacting the front surface  32  of the plate protector  30 . During insertion and removal of the phosphor imaging plate  10  from the plate protector  30 , the active side  12  of the phosphor imaging plate  10  slides along in contact with the front surface  32  of the plate protector  30 . This physical interaction between the front surface  32  of the plate protector  30  and the phosphor imaging plate  10  can cause damage to the top protective coating layer  20  and, eventually, the phosphor coating layer  22 . 
         [0014]      FIG. 4  depicts a perspective view of an exemplary CR scanner  50 , which can comprise a scanner section  52  that includes the scanner lasers (not shown) and transport mechanism (e.g., rollers) (not shown) for scanning and transporting the phosphor imaging plate  10  that is fed into the scanner section  52  by curving the plate  10  around and onto the curved inlet drum  54  and is output from the scanner section  52  onto the curved outlet drum  56 . In the exemplary CR scanner  50  shown, the phosphor imaging plate  10  is fed into the scanner section  52  with the active side  12  facing the curved inlet drum  54 . 
         [0015]    In the case where a plate protector  30  is not employed, the active side  12  of the phosphor imaging plate  10  is curved around and placed in contact with the curved inlet drum  54  and then fed into and then transported by the scanner section  52 . During transport, the active side  12  of the phosphor imaging plate  10  slides along in contact with the curved inlet drum  54 . This physical interaction between the curved inlet drum  54  and the phosphor imaging plate  10  can cause damage to the top protective coating layer  20  and, eventually, the phosphor coating layer  22 . 
         [0016]    In the case where a plate protector  30  is employed, the back surface of the plate protector  30  is placed on and in contact with the curved inlet drum  54  such that the active side  12  of the phosphor imaging plate  10 , which is facing and contacting the front surface  32  of the plate protector  30 , is facing the curved inlet drum  54 . The plate protector  30  can be fed into the scanner section  52  until the guide flaps  34 ,  36  come in contact with and are stopped by the scanner section  52 . At that point, the phosphor imaging plate  10  is further fed into and then transported by the scanner section. During transport, the active side  12  of the phosphor imaging plate  10  slides along in contact with the front surface  32  of the plate protector  30 . This physical interaction between the front surface  32  of the plate protector  30  and the phosphor imaging plate  10  can cause damage to the top protective coating layer  20  and, eventually, the phosphor coating layer  22 . 
         [0017]    In order to reduce damage to the phosphor imaging plate  10  caused by a physical interaction between a surface and the active side  12  of the phosphor imaging plate  10  as the plate  10  is slid or transported along the surface, in one embodiment of the invention, protective material strips  60  of a relatively soft material (e.g., velvet) or non-stick material (e.g., TEFLON) that will not scratch the plate  10  are affixed to the surface. One example of a suitable velvet material can be provided by Schlegel LS12.00661. For example,  FIG. 5  is a top view of an exemplary plate protector  30  in one embodiment of the invention with protective material strips  60  affixed to the front surface  32 . Similarly,  FIG. 6  is a perspective view of an exemplary CR scanner  50  in one embodiment of the invention with protective material strips  60  affixed to the curved inlet drum  54 . The protective material strips  60  can be affixed to the surface using an adhesive agent or other bonding method. 
         [0018]    In each of these embodiments, the thickness, width, quantity, and spacing of the protective material strips  60  affixed to the surface are chosen to ensure that active side  12  of the phosphor imaging plate  10  contacts the protective material strips  60 , which will not cause any damage, as the phosphor imaging plate  10  is slid or transported along the surface. This reduces the physical interaction between the phosphor imaging plate and the surface. In addition, the protective material strips  60  are oriented in the direction of travel of the phosphor imaging plate  10 . Alternatively, the protective material strips  60  could be oriented perpendicularly (or in any other direction with respect) to the direction of travel of the phosphor imaging plate  10 . In addition, rather than using protective material strips  60  spaced apart on a surface as shown in  FIGS. 5 and 6 , the protective material can be used to cover the entire surface for a particular application. 
         [0019]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.