Abstract:
A container for an imaging plate includes a sealable envelope, in which the plate is inserted, and one or more flaps, fixed to the envelope, which are closed by an operator so as to seal the plate inside the envelope. The flaps are then pulled open by the operator in order to release the plate from the envelope substantially without physical contact by the operator with the plate. Typically, the flaps are folded over the envelope and fixed one to another, creating a fold that seals the envelope shut.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to digital radiography devices and specifically to devices for dental radiography based on reusable X-ray media. 
     BACKGROUND OF THE INVENTION 
     Historically intraoral dental radiography has been based on X-ray film. Since the film is used only once, there is no need for re-sterilization after use. 
     Recently, however, the dental field is moving toward digital radiography systems with reusable image receivers, such as Photostimulable Phosphor (PSP) plates. A PSP plate is inserted in the patient&#39;s mouth and exposed to X-rays, like a standard film. The exposed plate is removed from the mouth and “developed” by a laser scanner, whereupon the image on the plate is displayed and stored by a computer. The plate is then erased, by a flash of bright light, and is ready for reuse. 
     With the advent of reusable image receivers, complications have emerged concerning the sterilization and maintenance of the reusable media. PSP plates are degraded by both the chemicals and heat that can be used to sterilize them between uses. Therefore, the plate must be sealed inside a suitable envelope before it is placed in the mouth. A special procedure must be followed to remove the plate from the envelope for development, in order not to compromise the plate&#39;s sterility. 
     SUMMARY OF THE INVENTION 
     It is an object of some aspects of the present invention to provide apparatus and method to preserve the sterility of reusable intraoral X-ray imaging media during oral procedures. 
     In preferred embodiments of the present invention, a reusable imaging media plate, such as a PSP plate, is inserted into a foldable plastic envelope having flaps which fold and seal the plate within the envelope. The seal protects the PSP plate and prevents contact with saliva or other body fluids. Preferably, the envelope comprises a release flap which allows extraction of the sterile PSP plate without physical contact with the plate. The plate thus remains uncompromised, and the necessity of sterilization is eliminated. 
     There is therefore provided, in accordance with a preferred embodiment of the present invention, a container for an imaging plate including: 
     a sealable envelope, in which the plate is inserted; and 
     one or more flaps, fixed to the envelope, which are closed by an operator so as to seal the plate inside the envelope, and which are pulled open by the operator in order to release the plate from the envelope substantially without physical contact by the operator with the plate. 
     Preferably, the one or more flaps are folded over the envelope, creating a fold that seals the envelope shut, wherein the one or more flaps are folded and fixed one to another in order to seal the envelope. 
     Further preferably, at least one of the flaps has a perforation, which is torn so as to pull the flap open. Preferably, the envelope includes first and second sides, which are peeled apart to open the envelope, wherein at least one of the flaps includes first and second sides connected respectively to the first and second sides of the envelope, such that the operator grasps and pulls the first and second sides of the at least one of the flaps to peel apart the envelope. 
     Typically, the imaging plate includes a reusable X-ray sensitive medium, wherein the imaging plate inside the container is inserted into the mouth of a patient for producing X-ray images thereof. 
     In a preferred embodiment, the container includes substantially opaque cover, which receives the imaging plate and inside which cover the plate is inserted into the envelope. Preferably, the cover further receives an X-ray shield, parallel to the imaging plate, for intercepting spurious X-rays. 
     There is also provided, in accordance with a preferred embodiment of the present invention, a method for preserving sterility of an imaging plate, including: 
     inserting the plate into a sealable envelope; 
     closing one or more flaps on the envelope so as to seal the plate inside the envelope; 
     exposing the plate to form an image thereon; and 
     pulling the one or more flaps open in order to release the plate from the envelope, substantially without making physical contact with the plate. 
     Preferably, closing the one or more flaps includes folding the flaps over the envelope so as to create a fold that seals the envelope shut, wherein folding the flaps includes fixing the flaps one to another in order to seal the envelope. Most preferably, pulling the one or more flaps includes tearing at least one of the flaps along a perforation thereon. 
     Further preferably, pulling the one or more flaps includes peeling apart first and second sides of the envelope using the flaps, wherein pulling the one or more flaps includes releasing the plate onto a receiving surface without touching the plate. 
     Preferably, the imaging plate includes a reusable X-ray sensitive medium, wherein exposing the plate includes inserting the plate in the container into the mouth of a patient so as to produce X-ray images thereof. 
     The present invention will be more fully understood from the following detailed description of the preferred embodiments thereof, taken together with the drawings in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified, pictorial illustration showing insertion of a reusable imaging plate into an envelope, in accordance with a preferred embodiment of the present invention; 
     FIG. 2 is a simplified, pictorial illustration showing the envelope of FIG. 1 after insertion of the plate; 
     FIG. 3 is a simplified, pictorial illustration showing sealing of the envelope; 
     FIG. 4 is a simplified, pictorial illustration showing the envelope containing the plate in use in a patient&#39;s mouth, in accordance with a preferred embodiment of the present invention; 
     FIG. 5 is a simplified, pictorial illustration showing removal of the plate from the envelope; 
     FIG. 6A is a schematic front view of a plate cover, in which a reusable imaging plate is inserted, in accordance with a preferred embodiment of the present invention; and 
     FIG. 6B is a schematic, sectional view of the cover of FIG. 6A, taken along a line VIB—VIB. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference is now made to FIG. 1, which is a simplified, pictorial illustration showing insertion of a reusable imaging plate  22  into an envelope  20 , in accordance with a preferred embodiment of the present invention. 
     Envelope  20  comprises a receptacle  21  which receives and holds a reusable image receiver plate  22 . Preferably plate  22  is a PSP plate, having a radiation-sensitive face  23 , and is inserted with face  23  facing forward, i.e. facing a front face  34  of envelope  20  as shown in FIG.  1 . Additionally, envelope  20  comprises a closure flap  29 , and a release flap  24 , whose functions are described hereinbelow. 
     Preferably, front face  34  of receptacle  21  is transparent, allowing face  23  of plate  22  to be seen and aiding in proper insertion of the plate in a patient&#39;s mouth (FIG.  2 ). Moreover, preferably a rear face  36  of receptacle  21  is opaque, protecting plate  22  from exposure to light and consequent fading. Faces  34  and  36  are made of a non-toxic, flexible plastic and are heat-sealed around an outer edge thereof, except for the opening through which the plate is inserted. 
     Preferably, flap  24  is perforated along a line  25 . Flap  29  has a peel-off tab  26  covering an adhesive coating  28 . The functions of these elements are described hereinbelow. 
     FIG. 2 is a simplified, pictorial illustration of envelope  20 , after insertion of plate  22  into receptacle  21 . Flap  24  and flap  29  are folded over to seal the plate inside receptacle  21 , such that flap  29  is folded over flap  24  and fixes flap  24  to face  34 . Note that the fold in flap  29  bends faces  34  and  36  together such that the opening in receptacle  21  is closed off. 
     FIG. 3 is a simplified, pictorial illustration showing sealing of plate  22  into envelope  20 . Flap  29  is fully folded over, creating a fold  32  which folds faces  34  and  36  over onto themselves, and seals shut the opening of receptacle  21 . Fold  32  forms a barrier against the entrance of bodily fluids, such as saliva, into receptacle  21 . In this configuration, envelope  20  with plate  22  inside is inserted into a patient&#39;s mouth. 
     FIG. 4 is a simplified, pictorial illustration showing sealed envelope  20  containing plate  22 , in use in a patient&#39;s mouth, in accordance with a preferred embodiment of the present invention. Envelope  20 , with plate  22  sealed within it, is positioned in a patient&#39;s mouth behind the teeth designated to be X-rayed. As shown in the figure, envelope  20  is preferably placed with the folded face directed outward, exposing face  23  of plate  22  to the X-ray beam. 
     FIG. 5 is a simplified, pictorial illustration showing removal of plate  22  from envelope  20  after exposure of an X-ray image. Flap  24  is split along the perforation in line  25 , releasing the flap and allowing faces  34  and  36  to be separated. Face  34  is then peeled off from face  36 , releasing plate  22  from the seal of receptacle  21 . Preferably, plate  22  is then allowed to fall from envelope  20  onto a sterile surface. The dentist preferably performs these steps without removing his gloves, which protect his fingers from contact with saliva on the envelope, while plate  22  is removed from envelope  20  without physical contact with the gloves. Envelope  20  thus preserves the sterility of plate  22  by providing an effective mechanism for protecting the plate from even indirect contact with saliva. 
     Although in the preferred embodiment described hereinabove, plate  22  is inserted, and envelope  20  is folded and sealed along a length of the envelope, i.e., a horizontal axis as seen in FIG. 1, in alternative embodiments, envelope  20  receives, folds, seals, and releases plate  22  along the width of the envelope, i.e., along a vertical axis in the view of FIG.  1 . Additionally, flaps  29  and  24  may have different contours from those shown, as long as they still fulfill the function of effectively sealing plate  22  into envelope  20 . 
     Moreover, although envelope  20  is shown and described herein in intraoral use, the principles of the present invention may be applied to maintain sterility of reusable imaging media in other medical and surgical applications, for example, in intraoperative X-ray imaging. 
     FIGS. 6A and 6B are schematic illustrations of a plate cover  40 , which receives plate  22  and is then inserted together with the plate into envelope  20 , in accordance with a preferred embodiment of the present invention. FIG. 6A is a front view, showing insertion of plate  22  into a pouch  42  formed between an outer layer  48  and a middle layer  46  of cover  40 . FIG. 6B is a sectional view of the cover and plate taken along a line VIB—VIB in FIG.  6 A. 
     Cover  40  preferably comprises an opaque, flexible plastic, so that when plate  22  is inserted in the container, the plate is protected from ambient light. Such protection is useful in preventing fading of the latent image formed on the plate by X-ray exposure between the time the plate (in envelope  20 ) is removed from the patient&#39;s mouth and the time the plate is inserted in a “developing” device for processing and digitization of the image. The inventors have found the protection to be particularly important when the dentist takes a sequence of images at different locations in the patient&#39;s mouth, and then develops all the images at once. In such a case there may be a substantial delay between exposing the image and developing it, during which time ambient light striking the plate can cause noticeable image degradation. Plate  22  is thus removed from cover  40  only immediately before development. The cover remains sterile, and can be reused without the need for cleaning or other processing. 
     As shown in FIG. 6B, cover  40  preferably includes a second pouch  44 , similar to pouch  42 . Pouch  44  is intended to receive an X-ray shield  50 , preferably comprising a small sheet of lead, which is of the same general size and shape as plate  22 . Cover  40  is inserted into envelope  20  and positioned in the patient&#39;s mouth so that plate  22  faces toward the tooth or teeth to be imaged, and shield  50  faces toward the inside of the mouth. The shield is required by some regulatory authorities in order to protect the mouth from radiation passing through the plate. Cover  40  thus provides a simple and convenient means for providing the required protection. It is also useful in preventing image degradation due to “back-scattered” radiation, which can occur when X-rays pass through plate  22 , scatter from other tissues in the mouth, and then strike the plate again. By absorbing substantially all such radiation, shield  50  helps to prevent loss of image contrast and addition of noise due to back-scattering. 
     It will be appreciated generally that the preferred embodiments described above are cited by way of example, and the full scope of the invention is limited only by the claims.