Patent Number: 
Section: description

Referring to FIGS. 1 and 2, X-ray beam irradiation apparatus 10 is suitable for sterilizing objects or articles, for example, medical instruments, tools or components. In the embodiment depicted in FIGS. 1 and 2, X-ray beam irradiation apparatus 10 includes an x-ray beam system having an X-ray irradiation unit 11 for irradiating articles 19. The X-ray irradiation unit 11 of the embodiment depicted in FIGS. 1 and 2 includes a series of X-ray beam emitters 12 each having a target window 16 through which an X-ray beam 22 is generated. The X-ray beam emitters 12 have angled side walls 14 which allow the X-ray beam emitters 12 to be abutted against each other and joined together in a ring 10a surrounding an irradiation region or chamber 20 so that the X-ray beam emitters 12 can direct the X-ray beams 22 radially inwardly into irradiation chamber 20 from different directions. FIGS. 1 and 2 depict six X-ray beam emitters 12 abutted against each other to form a hexagonal shaped irradiation chamber 20. The target windows 16 are closely positioned to each other so that the X-ray beams 22 directed into irradiation chamber 20 combine to provide substantially continuous radially inward X-ray beam coverage. In use, articles 19 (FIG. 1) such as medical instruments requiring sterilization are typically positioned within irradiation chamber 20. Doors, such as those shown in FIG. 3, designated by reference numeral 26, may be employed on opposite ends of irradiation chamber 20 to provide shielding of the X-rays. Alternatively, elongated entrance and exit tunnels can be employed to provide shielding. Power to the X-ray beam emitters 12 is then provided so that X-ray beams 22 are directed inwardly into irradiation chamber 20. The X-ray beams 22 are able to disable, damage or kill bacteria, viruses, and organisms on the surface of the article 19. In addition, the X-ray beams 22 can penetrate into the article 19 to sterilize regions deep within the article 19 as well as penetrate and sterilize thick layers or regions of contamination. Instruments such as an endoscope may require a sterilization time of about a half hour at a low power of 5 kW per emitter 12 to achieve thorough sterilization. This is about half the time in comparison to the one hour typically required when sterilizing with hydrogen peroxide. Even over such an amount of time, instruments sterilized by hydrogen peroxide are not as thoroughly sterilized as in the present invention. Although six X-ray beam emitters 12 are shown in FIGS. 1 and 2 to form X-ray irradiation unit 11, it is understood that any number of X-ray beam emitters 12 can be employed. When three emitters 12 are employed, irradiation chamber 20 can be triangular in shape, with four emitters 12, square, and with five and above, polygonal. When multiple emitters 12 are employed, irradiation chamber 20 can also have configurations that are wide and flat, or convoluted, depending upon the situation. In some cases, X-ray irradiation unit 11 may only need one or two X-ray beam emitters 12. In such cases, reflectors for reflecting X-rays can be used in combination with the X-ray beam emitters 12. Additionally, although x-ray emitters 12 have been shown to be joined together in a ring 10a, alternatively, one or more X-ray emitters 12 may be positioned for providing X-ray beams that are not in a substantially continuous circle, for example, from one or two directions. When two X-ray beam emitters 12 are employed, the emitters 12 can be arranged in opposed fashion. Referring to FIG. 3, X-ray beam irradiation apparatus 24 is employed when sterilizing articles 19 that are too long to fit within apparatus 10. X-ray beam irradiation apparatus 24 includes an X-ray beam system having more than one X-ray irradiation unit 11 joined together. In one embodiment, each X-ray irradiation unit 11 includes a ring 10a of X-ray beam emitters 12 similar to that depicted in FIGS. 1 and 2. The rings 10a are abutted against each other and joined together so that the irradiation chambers 20 of each ring 10a join together collectively to form one long irradiation region or chamber 28. Three X-ray irradiation units 11 are shown abutted together, however, less than three or more than three units 11 can be joined together. Typically, X-ray beam irradiation apparatus 24 includes doors 26 to provide shielding of the X-rays. Although instruments are typically positioned in a stationary manner within irradiation chamber 28, alternatively, a conveyor system can be employed to slowly move articles 19 through irradiation chamber 28. The conveyor system may include conveyor belts and/or rollers. When a conveyor system is employed, entrance and exit tunnels may be desirable to provide shielding. It is understood that X-ray irradiation apparatus 24 can have X-ray irradiation units 11 of configurations that are different than ring 10a such as discussed above. In addition, some embodiments of the irradiation units 11 can include mechanisms for moving one or more emitters 12 over or around an article 19 for providing X-ray irradiation with a minimum number of emitters 12. In one embodiment, a ring 10a is translated longitudinally along article 19. In another embodiment, an emitter 12 is rotated around article 19 and can also be translated longitudinally over article 19. In configurations where an emitter 12 is rotated around article 19, employing more than one emitter 12 can reduce the amount of rotation required. For example, if two emitters 12 are employed positioned in opposed fashion, the emitters 12 can be rotated only 180xc2x0 around article 19. In addition to sterilizing medical instruments, tools or components, X-ray beam irradiation apparatuses 10 and 24 can be employed to sterilize implantable devices or components such as artificial joints, pins, plates, pumps, pacemakers, etc. Furthermore, a wide variety of objects or articles 19 can be sterilized, including items for use in a sterile room or environment. In some instances, it may be desirable to sterilize substances such as powders, liquids or food items. Referring to FIG. 3, X-ray beam irradiation apparatus 24 can be employed as a sterilizing entrance for articles 19 entering a sterile environment where one end of apparatus 24 is connected to the sterile environment, typically, extending through a wall thereof. One door 26 allows articles 19 to be inserted into apparatus 24 from the exterior for sterilization. The other door 26 allows removal of the sterilized article 19 from apparatus 24 into the sterile environment. Referring to FIGS. 4 and 5, X-ray beam emitter 12 in one embodiment includes a hermetically sealed vacuum chamber 30 having a rectangular target window 16 positioned at one end thereof. An electron generator 32 is positioned within the interior 30a of vacuum chamber 30 for generating electrons exe2x88x92 which are accelerated towards the target window 16 for forming X-rays. The target window 16 typically consists of a thin metallic foil that has a thickness sufficient to substantially prevent the passage of electrons exe2x88x92 through while allowing passage of X-rays. The target window 16 is supported by a support plate 38 having a series of holes 38a therethrough which allow the electrons exe2x88x92 to reach target window 16. In some embodiments, outwardly angled holes 38b may be included at the far ends of support plate 38 (FIG. 5) to direct more electrons exe2x88x92 to the ends of target window 16. The target window 16 is sealed to support plate 38 by bonding under heat and pressure, but alternatively could be brazed or welded. In one embodiment, the target window 16 can be 12 inches long so that irradiation chamber 20 is about 12 inches long. When X-ray beam emitters 12 are to be abutted against each other in a ring such as ring 10a (FIG. 1), the emitters 12 can have angled sides 14 which extend towards and near the longer sides of the target window 16 (FIG. 4). Sides 14 are angled at about 60xc2x0 when six emitters 12 are abutted together, however, the angle of sides 14 can differ depending upon the number of emitters 12 joined together. In some irradiation chamber 20 configurations, the angled sides 14 can be omitted, for example, in some rectangular configurations. A tube may be extended from vacuum chamber 30 and connected to a vacuum pump for evacuating vacuum chamber 30 which is then sealed off to hermetically seal vacuum chamber 30. The electron generator 32 has a filament housing 34 which in one embodiment is disc shaped and has a series of openings in the bottom 34a. Tungsten filaments 36 are positioned within housing 34 for generating the electrons exe2x88x92. Filament housing 34 is electrically connected to a high voltage supply by tubular conductor 40a and cable 18. Common ranges are 100-300 kV with 125 kV being typical. In some applications, voltages 100 kV and above 300 kV may be desirable. Target window 16 is electrically grounded to impose a high voltage potential between filament housing 34 and target window 16. Filaments 36 are provided power by a filament power supply electrically connected to cable 18 and are electrically connected at one end to a conductor 42 extending within the interior of filament housing 34, and are electrically connected at the other end to a conductor 40b extending from cable 18. The upper portions of conductor 40a is embedded within insulating materials 44. In use, the filaments 36 are provided with power to heat filaments 36 to about 3400xc2x0 F. to 4200xc2x0 F. which causes free electrons exe2x88x92 to form on filaments 36. The high voltage potential imposed between the filament housing 34 and target window 16 causes the free electrons exe2x88x92 on filaments 36 to accelerate from the filaments 36 in a beam through openings in the bottom 34a of filament housing 34 to target window 16. The target window 16 is typically a thin foil of gold, titanium or tungsten about 3 microns thick which substantially blocks or prevents the passage of electrons exe2x88x92 therethrough, but, alternatively, may be formed of titanium with a layer of gold thereon, or be formed of gold with copper or silver. Typically, metals with a high Z number and good thermal conductivity are preferred, but it is understood that the material of target window 16 can vary depending upon the application at hand. For example, materials and combinations other than those described above can be used. The electrons exe2x88x92 striking the target window 16 typically do not pass through but instead form X-rays which exit or emerge from the target window 16 in an X-ray beam 22 and continue to travel substantially in the same forward direction as the electrons exe2x88x92 were traveling. In other words, the beam of electrons exe2x88x92 is transformed or changed by target window 16 into the X-ray beam 22 resulting in a continuous two-part or stage beam where the first stage is formed by the beam of electrons exe2x88x92 and the second stage is formed by the X-ray beam 22. The X-ray beam 22 exits target window 16 with substantially the same outline as target window 16. The production of X-rays in this manner provides a relatively efficient broad X-ray beam 22 because both the electrons exe2x88x92 and the X-ray beam 22 are traveling in the same forward direction. The beam of electrons exe2x88x92 and the X-ray beam 22 are shown to be perpendicular or substantially perpendicular to target window 16. In some situations, electrons exe2x88x92 might strike target window 16 at an angle. In some embodiments, target window 16 may be configured to allow some electrons exe2x88x92 to pass through to provide a mix of electrons exe2x88x92 and X-rays. In further embodiments, the target window 16 can be replaced by an electron beam exit window which allows the electrons exe2x88x92 to exit the emitters 12 in an electron beam. In such a case, the electrons exe2x88x92 strike the surface of the article to be sterilized thereby sterilizing the surface and, at the same time, creating X-rays which sterilize the interior. Such an embodiment can be used to sterilize or decontaminate any type of suitable equipment. The target window 16 can be configured to suit particular arrangements, and can be of shapes other than rectangular. While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For example, features of the various embodiments discussed above may be combined with each other or omitted. It is understood that the configuration, shape, dimensions, size and power of X-ray emitter 12 can be varied depending upon the application at hand as well as the shape of the target window 16. Multiple emitters 12 may be positioned side by side for generating an X-ray beam 22 from one direction, or positioned in opposing directions for generating X-ray beams 22 from two directions. In some configurations, the X-ray beams 22 from emitters 12 are not joined in a continuous manner. In addition, X-ray emitters 12 and apparatuses 10 and 24 may be employed to sterilize any desired article, or may be used for other typical purposes, such as taking an X-ray of a patient or curing coatings.