Abstract:
A variable aperture X-ray collimating device that fits over existing intraoral radiographic sensor positioners enables clinicians to provide radiation protection for their patients while allowing the flexibility to accommodate various commercially available positioning kits. In addition, the variable aperture allows for easy accommodation of various sensor sizes.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority from U.S. Ser. No. 61/661,322, filed Jun. 18, 2012, the disclosure of which is specifically incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The field of the present invention is dentistry and, specifically, devices used by dentists when taking intra-oral radiographs with dental X-ray film or an intra-oral digital dental sensor. 
     BACKGROUND OF THE INVENTION 
     The rectangular collimator is a dental device that has been used in conjunction with external positioning devices intended to give proper geometric alignment between the X-ray generator, the patient&#39;s teeth and the X-ray film or digital radiographic sensor. The purpose of the rectangular collimator is to restrict the size of the X-ray beam to approximately the size of the imaging field of the film or sensor. This protects the patient against unnecessary radiation exposure and improves image quality by reducing side scatter. 
     Such devices also improve image quality by reducing X-ray side scatter from anatomic structures outside the imaging field of view but within the uncollimated X-ray beam. 
     The main deficiency in the current design of all rectangular collimating devices is the user&#39;s inability to adjust the size of the rectangular opening to match that of the actual X-ray film or digital sensor size to minimize the non-imaging patient X-ray exposure. 
     There are three common sizes of intra oral x-ray film or digital sensors commonly used in dentistry: Size 0, size 1, and size 2. The existing rectangular collimators are usually slightly larger than the size 2 X-ray film or digital sensor. 
     A rectangular collimating device with the adjustability for the three different size imaging fields would further reduce the patient&#39;s X-radiation exposure by matching the rectangular opening of the collimator to the specific film or sensor size used. 
     SUMMARY OF THE INVENTION 
     The present invention is generally directed to attachments useful with an external ring and rod x-ray film or digital sensor holder system. An adjustable aperture rectangular collimating device will reduce the area of the active X-ray beam to properly match the active area of the X-ray film or digital sensor. This will promote better radiation hygiene in the dental profession and reduce unnecessary and unproductive X-ray exposure to the patient during dental X-ray exams. 
     Accordingly, it is primary object of the present invention to provide for an adjustable aperture rectangular collimating device to be used in conjunction with existing x-ray film or digital sensor holder systems. 
     This and further objects and advantages will be apparent to those skilled in the art in connection with the drawings and the detailed description of the invention set forth below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a prior art intraoral radiology positioning device that has been retrofitted with a rectangular collimation attachment and 
         FIG. 2  is an exploded view of  FIG. 1  illustrating the near and far side cover of the rectangular collimation attachment of  FIG. 1  detached from the intraoral radiology positioning device. 
         FIGS. 3A and 3B  illustrate a retrofit rectangular collimation attachment according to the present invention with sliding shutters. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention provides a retrofit solution for allowing an intraoral radiology positioning device to be retrofit with a rectangular collimation attachment. 
     As illustrated in  FIGS. 1 and 2 , a standard intraoral radiology positioning device, generally designated as  1 , has an a guide arm  2 , an aiming ring  3  attached to guide arm  2 , and bite block  4  and sensor basket  5  attached at one end of guide arm  2 . Details of such a standard intraoral radiology positioning device are set forth in U.S. Pat. No. 6,343,875, the disclosure of which is specifically incorporated herein by reference. 
     The present invention provides a retrofit collimation attachment, generally designated as  10 , which is designed to secure itself about guide arm  2  of intraoral radiology positioning device  1 . Retrofit collimation attachment  10  is comprised of a near side cover  11  and a far side cover  15  (preferably made out of plastic that will withstand autoclaving) that are designed to fit about guide arm  2  and then releasably attach themselves together so as to secure a collimation plate, generally designated as  20 , with a collimation aperture  21  that is within the opening of aiming ring  3  relative to an intraoral X-ray device. Either or both of near and far side covers  11  and  15  can be adapted to hold a collimation plate which will form collimation plate  20  and either or both of near and far side covers  11  and  15  can be fitted with one or more handles  30  for ease of use by a patient. It is especially preferred that near side cover  11  has its own near side collimation plate  12  having an aperture  13  and far side cover  15  has its own far side collimation plate  16  having an aperture  17 , which allows the thickness of each such plate to be half what would otherwise be required to provide a sufficient amount of thickness for collimation plate  20  to block X-ray radiation. In an especially preferred embodiment, near and far side collimation plates  12  and  16  are made of stainless steel and each have a thickness of approximately 1 mm so that, together, the two plates will provide 2 mm of steel protection for collimation plate  20  and apertures  12  and  13  will be aligned so as to form collimation aperture  21 . 
     Because ease of use and adaptability are key goals of the present invention, it is especially preferred that retrofit collimation attachment  10  can easily be adapted to provide different sizes for collimation aperture  21  so that a user can choose the correct opening that corresponds to the proper size of the imaging media (size #1, #1, or #2), whether it be X-ray film or a digital sensor. A first way this can be accomplished is to simply use a different retrofit collimation attachment  10  for each different desired size of collimation aperture  21  (which will generally have a rectangular shape). A second way this can be accomplished is for one or both of near and far side collimation plates  12  and  16  to be readily detachable from, and thus easily interchangeable with, another plate with a different size aperture. Accordingly, either or both of near and far side collimation plates  12  and  16  might, for example, be snap fit into, respectively, near and far side covers  11  and  15 . A third way this can be accomplished is for collimation aperture  21  to be adjustable (such as, by example, use of sliding shutters that can be moved between two or more positions as illustrated in  FIG. 3 ). 
     Near and far side covers  11  and  15  should function together so as to provide a quick and easy way to releasably connect them together about aiming ring  3 . An especially preferred way in which this can be accomplished is for near and far side covers  11  and  15  to snap-fit together, although any suitable means for such attachment can be used such as, but not limited to: threaded screw, ball and socket, friction grip, male/female connectors, clamp, magnetic, suction, fixed or removable adjustable ring/band, Velcro, single or double sided adhesive, inelastic ring/band, elastic ring/band, adjustable ring/band, and the like. 
     While the invention has been described herein with reference to certain preferred embodiments, those embodiments have been presented by way of example only, and not to limit the scope of the invention. Additional embodiments thereof will be obvious to those skilled in the art having the benefit of this detailed description. 
     Accordingly, it will be apparent to those skilled in the art that still further changes and modifications in the actual concepts described herein can readily be made without departing from the spirit and scope of the disclosed inventions.