Patent Publication Number: US-2013240763-A1

Title: Apparatus and methods for reducing soiling of radio-opaque shields

Description:
TECHNICAL FIELD 
     This disclosure relates generally to shields that attenuate ionizing radiation. More specifically, this disclosure relates to apparatus for maintaining the shields and garments that attenuate ionizing radiation in a clean and/or hygienic state, 
     RELATED ART 
     A variety of shields and garments have been developed to limit exposure of individuals to ionizing radiation (e.g., x-rays, gamma rays, etc.). Examples of such shields and garments include aprons, thyroid shields and gloves. Conventionally, ionizing radiation-attenuating shields and garments are lead (Pb)-based, as lead has tong been the material of choice for attenuating ionizing radiation, Other materials that attenuate ionizing radiation, which are also referred to as “radio-opaque” materials, including lead-based materials and lead-free materials, have also been used in ionizing radiation-attenuating shields and garments, The radio-opaque material of a shield or garment is typically encased in a manner that ensures that the shield or garment will uniformly limit attenuate a desired amount, or intensity, of ionizing radiation. In many implementations, the encased radio-opaque material is then covered with an outer layer, which may impart the shield or garment with a pleasant look or feel, and may be configured with one or more features that enable the shield or garment to be secured to an individual&#39;s body. 
     For a variety of reasons, including the expense of radio-opaque materials, shields and garments that attenuate ionizing radiation are typically configured to be used repeatedly, often over long periods of time (typically years). With repeated use, the outer layers of shields or garments may be soiled or contaminated (e.g., with microorganisms, etc.), they may absorb odors or their presentation may otherwise be diminished. For the sake of simplicity, any action that might diminish the presentation of a shield or garment is referred to herein as “soiling” or some variant of that term. Soiling may be caused by a variety of factors, including, without limitation, as an individual&#39;s perspiration comes into contact with the shield or garment, as the garment is exposed to foreign substances (makeup, perfume, deodorant, microorganisms, body fluids, etc.) on an individual&#39;s body and as foreign substances from the environment in which the shield or garment is used come into contact with the shield or garment. 
     In some environments (e.g., hospitals, doctor&#39;s offices, dental offices, etc.), people have high expectations of cleanliness and even sterility. A shield or garment may be used on a large number of different people (e.g., patients, etc.) in such an environment, or individuals (e.g., patients, etc.) may see a worker (e.g., a healthcare provider, etc.) in such an environment wearing a shield or garment configured for repeated use. The presence and use of a soiled ionizing radiation-attenuating shield or garment in such an environment may be viewed unfavorably by visitors to (e.g., patients receiving care in, etc.) that environment. Furthermore, any contaminants on a shield or garment may be undesirably transferred to other individuals (e.g., patients, healthcare workers, etc.) who are present in the same setting. 
     SUMMARY 
     In various aspects, this disclosure relates to apparatuses and techniques for minimizing soiling of or removing soiling from ionizing radiation-attenuating shields and garments that are configured for repeated use. Such shields and garments, which are collectively and more simply referred to hereinafter as “shields,” may be configured to attenuate one or more types of ionizing radiation (e.g., x-rays, gamma rays, etc.). 
     In one aspect, this disclosure relates to shields with outer layers that are configured to minimize soiling, such as by resistance to soiling, by facilitating the ready removal of soiling and/or by eliminating one or more types of soiling. Structures, such as the outer layer of a shield, that are configured to minimize soiling are referred to herein as “soil-minimizing” structures. In embodiments where a soil-minimizing outer layer is configured to resist soiling, the material of the outer layer may resist soiling, the material of the outer layer may be coated with a material that resists soiling or the outer layer may be formed from a soil-resistant material and include a soil-resistant coating. in embodiments where a soil-minimizing outer layer is configured to reduce or eliminate soiling, the material from which the outer layer is formed may comprise or carry a material or a combination of materials that remove or otherwise eliminate certain types of soiling (e.g., odors, microorganisms, etc.). Alternatively, or in addition, a soil-minimizing outer layer may comprise a “cleanable outer layer,” which may be formed from a material from which contaminants, odors and other types of soiling are readily removed (e.g., by wiping, with disinfectants and/or deodorants, by washing or other types of cleaning, etc.). In some embodiments, a shield that includes a soil-minimizing outer layer may be configured to withstand sterilization while maintaining its ability to minimize soiling. 
     In another aspect, this disclosure relates to removable shells for shields. A removable shell may be configured to be positioned over and secured to any type of shield, including a conventional shield or a shield with a soil-minimizing outer layer. A removable shell may be configured to be positioned and retained over a shield white the shield is in use, and to be removed from the shield when the shield is not in use. In some embodiments, a removable shell may simply provide a barrier that prevents soiling of the shield. In other embodiments, the removable shell may comprise a soil-minimizing material. 
     A removable shell may be configured for re-use (e.g., it may be configured for cleaning, washing, etc.) or it may be configured to be disposed of once its soiling becomes apparent. In some embodiments, particularly where a shield will be used in a sanitary or sterile environment, a shell may be configured to be sterilized. 
     Other aspects of the inventive subject matter of this disclosure, as well as features and advantages of various aspects of that subject matter, will become apparent to those of ordinary skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  illustrates an embodiment of a shield for attenuating ionizing radiation, which shield includes a soil-minimizing outer layer; 
         FIG. 2  is a cross-section of the shield shown in  FIG. 1 ; 
         FIG. 3  depicts an embodiment of a shell for use with a shield that attenuates ionizing radiation; 
         FIG. 4  shows an embodiment of the manner in which the shell of  FIG. 3  may be secured to a shield that the shell is configured to complement; 
         FIG. 5  is a cross-sectional representation of the assembly shown in  FIG. 4 ; 
         FIG. 6  illustrates another embodiment of a shell for use with a shield that attenuates ionizing radiation; 
         FIG. 7  shows an embodiment of the manner in which the shell of  FIG. 6  may be secured to a shield that the shell is configured to complement; and 
         FIG. 8  is a cross-sectional representation of the assembly depicted by  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments of apparatuses and techniques for minimizing soiling of shields that attenuate ionizing radiation are described herein. Among other embodiments, a shield may be configured in a way that minimizes its own soiling or a shell may be configured to prevent soiling of a shield. Methods in which soiling of shields is minimized are also described. 
     In  FIGS. 1 and 2 , an embodiment of a shield  10  that minimizes ionizing radiation is illustrated. That shield  10  includes a radio-opaque material  12 , an encapsulant  13  and an outer layer  19 . The radio-opaque material  12  is distributed across much of the area defined by the shield  10 . The encapsulant  13  may contain the radio-opaque material  10  and ensure that the radio-opaque material  12  remains distributed across its intended area. The outer layer  19  covers the encapsulant  13 , and may impart the shield  10  with a desired look or feel. 
     Without limiting the scope of the disclosed subject matter, the radio-opaque material  12  may comprise any material that is known to attenuate ionizing radiation to a degree that is suitable for use in a garment or shield intended to limit an individual&#39;s exposure to ionizing radiation. In conventional shields  10 , the radio-opaque material  12  often comprises lead or a lead-based material. In some embodiments, in addition to lead and/or a lead-based material, the radio-opaque material  12  may include other metals, such as tin, tungsten, antimony, barium, etc. 
     A radio-opaque material  12 , such as lead or a lead-based material, is typically blended with an encapsulant  13 . In various embodiments, the radio-opaque material  12  is in a particular form, such as a powder, small particles or larger pellets. The encapsulant  13  may comprise a flexible material; for example, an elastomer such as a synthetic rubber, polyvinyl chloride (PVC) or the like. In some embodiments, the radio-opaque material  12  and the encapsulant  13  are homogeneously mixed and formed into sheets  14 . In some embodiments, the encapsulant  13  may comprise or be blended with a material that minimizes soiling. Non-limiting examples of such materials include soil-reducing agents (as described in further detail hereinafter), deodorants, antimicrobial agents and the like. 
     As an alternative to conventional radio-opaque materials, the radio-opaque material  12  of a shield  10  of the present invention may comprise a non-toxic material and/or a material based on an element having an atomic number of  56  or greater. Non-limiting examples of such elemental species include barium species, bismuth species and lanthanum species. In some embodiments, the radio-opaque material  12  may comprise an inorganic salt. Non-limiting examples of non-toxic, radio-opaque inorganic salts include barium sulfate and bismuth oxide. Such materials are disclosed in U.S. patent application Ser. No. 12/897,611, titled “RADIO-OPAQUE FILMS OF LAMINATE CONSTRUCTION” and filed on Oct. 4, 2010 (hereinafter “the &#39;611 Application”), the entire disclosure of which is, by this reference, hereby incorporated herein. 
     When radio-opaque materials  12  such as those disclosed by the &#39;611 Application are used in a shield  10 , they may comprise particles (e.g., fine particles of a powder, larger particles, pellets, etc.) that be homogenously mixed with and held together by a binder, or encapsulant  13 . 
     In some embodiments, the types of radio-opaque materials  12  disclosed by the &#39;611 Application may be encapsulated with a flexible material, Examples of suitable encapsulants  13  include, but are not limited to, elastomers such as a synthetic rubber, polyvinyl chloride (PVC) or the like. In some embodiments, the radio-opaque material  12  and the encapsulant  13  are homogeneously mixed and formed into sheets  14 . 
     Alternatively, particles of radio-opaque materials  12  of the types disclosed by the &#39;611 Application may bound together with a material that will hold particles of the radio-opaque material  12  together without causing a substantial decrease in the density of the radio-opaque material. Such a binder material is also referred to herein as an encapsulant  10 . The encapsulant  13  may hold particles of radio-opaque material together loosely, it may provide a stronger bond between adjacent particles, and/or it may enable the formation of a smooth uniform coating, or film. Examples of materials that may be suitable for use as the encapsulant  13  include, but are not limited to, elastomers, such as polyvinyl alcohol (PVA), polyvinyl butyrol (PVB), polyethylene glycol (PEG), glycerine, capric triglyceride, cetyl alcohol, glyceryl sterate and combinations of any of these materials. In addition, in some embodiments, the encapsulant  13  comprise or be blended with a material that minimizes soiling, such as a soil-reducing agent (as disclosed in further detail hereinafter), a deodorant, an antimicrobial agent or the like. As disclosed by the &#39;611 Application, the radio-opaque material  12  and a binder-type encapsulant  13  may be disposed between a pair of containment layers  17 , such as polymer films, foils, or the like, to form sheets  14 . 
     Two or more (e.g., up to five, etc.) of the sheets  14  may be used to form a laminate structure  15 . A cover  16  may be provided over (e.g., secured to, etc.) the laminate structure  15 . The cover  16 , which may comprise a flexible material, may provide a seal for the laminate structure  15 . In some embodiments, the cover  16  may comprise a fabric formed from synthetic fibers (e.g., nylon, etc.) and/or from a material that minimizes soiling, embodiments of which are described in detail hereinafter in reference to the outer layer  19 . A polymer film  17  may coat a surface of the cover  16  disposed against the laminate structure  15 . In some embodiments, the cover  16  may comprise an outer layer  19  of the shield  10 . 
     The outer layer  19  of a shield  1  that incorporates teachings of this disclosure may comprise a material that resists soiling, a material that reduces or eliminates soiling, or a material from which soiling is readily removed. 
     In embodiments where a shield  10  is configured to resist soiling, its outer layer  19  formed from a material that resists soiling, the material of its outer layer  19  may be coated or otherwise treated with a material that resists soiling, or the outer layer  19  may include a soiling-resistant material treated with soiling-resistant material, In some embodiments, the outer layer  19  of the shield  10  may include a plurality of different soiling-resistant materials, which may resist the same types of soiling, similar types of soiling or different types of soiling. 
     Various embodiments of materials that resist soiling include, but are not limited to, use of materials that are generally water-repellant, or hydrophobic. Hydrophobic materials that may be used to form fibers and, thus, fabrics, include polyesters, polyamides, polypropylenes and other synthetic materials. In some embodiments, the material of the outer layer  19  may comprise a stain-resistant material (which is has both water-repellant and oil-repellant properties), such as NANOTEX® fabric available from Nano-Tex of Oakland, Calif. 
     A variety of hydrophobic materials, including polyesters, polyamides, polypropylenes and a variety of other materials may also be used to treat fabrics, including fabrics formed from synthetic fibers and/or natural fibers. Stain-resistant treatments may also be used to treat the fabric(s) from which the outer layer  19  of a shield is formed. A non-limiting example of such a treatment is SCOTCH GUARD®, a perfluorobutaensulfonic acid (PFBS)-based product available from the 3M Company of St. Paul, Minn. Other non-limiting examples of such materials are disclosed by U.S. Pat. Nos. 6,472,476, 6,517,933, 6,544,594, and 6,855,772, the entire disclosures of each of which are, by this reference, hereby incorporated herein. 
     Alternatively, or in addition, the outer layer  19  of a shield  10  may comprise a material that reduces or eliminates soiling. Such materials may include, but are certainly not limited to, materials that include anti-microbia(agents (e.g., silver, silver-based antimicrobials, slime-based antimicrobials, 2-anthraquinone carboxylic acid, etc.). 
     The material of the outer layer  19  of a shield  10  may include a deodorant. 
     In some embodiments, the material(s) from which the outer layer  19  is formed may comprise a self-cleaning agent. In one example, a self-cleaning agent my comprise N—TiO 2  nanoparticles (i.e., particles that include a complex of titanium dioxide (TiNO 2 ) and nitrogen (N) ions), as disclosed by Wu, D., et al., “Realizing Visible-Light-Induced Self-Cleaning Property of Cotton through Coating N—TiO 2  Film and Loading AgI Particles,” Appl. Mat. &amp; Interfaces 3(12): 4770-74 (2011), the entire disclosure of which is, by this reference, hereby incorporated herein. N—TiO 2  nanoparticles may be activiated by exposure to sunlight. In some embodiments, N—TiO 2 nanoparticles may be used in conjunction with other materials to impart the material with additional self-cleaning properties. In a specific embodiment, silver iodide (AgI) nanoparticles may accelerate the ability of the N—TiO 2  nanoparticles to break down certain types of stains. 
     As another alternative, the outer layer  19  of a shield  10  may comprise a material from which contaminants, odors and other types of soiling may be readily removed. A cleanable outer layer  19  may comprise a material that may be cleaned (e.g., with water, with organic solvents or cleaning fluids, etc.) without requiring that the outer layer  19  be removed from the remainder of the shield  10  (i.e., from the encapsulant  13 ). Alternatively, or in addition, a cleanable outer layer  19  may be removable from and replaceable on the encapsulant  13 . 
     In embodiments where the outer layer  19  may remain in place over the encapsulant  13  of a shield  10 , the outer layer  19  may be formed from a material that does not absorb contaminants or that resists absorption of contaminants (e.g., a fabric with an internal waterproof coating, etc.). Such a material may enable the soiling to be removed from the outer layer  19  by wiping, use of pressurized fluid (e.g., compressed air, sprayed liquid, etc.), or otherwise. 
     Regardless of how the outer layer  19  of a shield  10  may minimize soiling, in some embodiments, the material(s) from which the outer layer  19  is formed may withstand sterilization while maintaining its ability to minimize soiling. Where an outer layer  19  of a shield may be sterilized, the shield  10  may be repeatedly used in sterile environments. 
     Turning now to  FIGS. 3 through 5 , an embodiment of a removable shell  20  for a conventional shield  10 ′ is depicted, and various embodiments of removable shells  20  are described. A removable shell  20  may comprise a fitted element configured to be placed over a particular, corresponding type of shield  10 °. Stated another way, the removable shell  20  has a configuration that resembles that of a shield  10 ′ over which the removable shell  20  is configured or tailored to be placed. In the illustrated embodiment, the removable shell  20  comprises a fitted element configured to be positioned over an apron-type shield  10 ′. 
     In the embodiment depicted by  FIGS. 3 through 5 , the removable shell  20  includes an attachment surface  21  and an opposite, outer surface  22 . The attachment surface  21  is configured to be placed against the shield  10 ′. The attachment surface  21  may, in various embodiments, carry an attachment element  23  that removably secures the removable shell  20  to the shield  10 ′. Without limitation, examples of the manner in which the attachment element  23  may function include adhesively (e.g., with a “low-tack,” reusable, pressure-sensitive adhesive material that leaves little or no residue when removed from a substrate (e.g., the adhesive used on POST-IT® brand products from the 3M Company, etc.), etc.), magnetically and mechanically (e.g., by way of complementarily configured snap-type elements, use of hook and loop type fasteners, etc.). 
     Although  FIGS. 3 through 5  only show a shell  20  on one surface of a shield  10 ′, shells may be positioned over and, optionally, secured to more than one surface (e.g., both inside and outside surfaces, etc.) of a shield  10 ′ to minimize soiling of a plurality of surfaces. 
     Alternatively,  FIGS. 6 through 8  illustrate an embodiment of removable shell  20 ′ that defines an envelope for enclosing at least a portion of a shield  10 ′. Such an embodiment of a removable shell  20 ′ includes an opening  24 ′. The opening  24 ′ may receive the shield  10 ′ as the removable shell  20 ′ is placed over the shield  10 ′. The shield  10 ′ may be withdrawn from the opening  24 ′ as the removable shell  20 ′ is removed from the shield  10 ′. In some embodiments, one or more fasteners  26 ′ (e.g., snaps, buttons, hook and loop type fasteners, adhesive elements, etc., which may be secured directly to the shell  20 ′ or to straps or other elements secured to the shell  20 ′) may reversibly close the opening  24 ′. 
     In any embodiment, the removable shell  20 ,  20 ′ may be formed from a soil-minimizing material (e.g., a material that resists soiling, a material that reduces or eliminates soiling, a material from which soiling is readily removed, etc.), such as those disclosed above in reference to the outer layer  19  of a shield  10  that self-minimizes soiling. 
     Alternatively, any type of material (e.g., fabric, polymer film, paper or paper-like material, etc.) that provides a sufficient barrier to prevent soiling of an underlying shield  10 ′ and that may be removed, cleaned and replaced on the shield  10 ′ may be used to form the removable shell  20 ,  20 ′. Stain-resistant materials, such as fabrics formed from synthetic fibers (e.g., nylon, polyester, etc.), may be used to make a removable shell  20 , for a shield  10 ′. 
     A removable shell  20 ,  20 ′ may include a radio-opaque material (e.g., it may include sublayer of radio-opaque material, as disclosed by the &#39;611 Application, it may be impregnated with a non-toxic radio-opaque material, etc.). The inclusion of a radio-opaque material in the removable shell  20 ,  20 ′ may enhance the radio-opacity of selected portions of the shield  10 ′ or of the entire shield  10 ′. 
     In use, a removable shell  20 ,  20 ′ may be placed on and secured to a complementarily configured shield  10 ′ prior to use of the shield  10 ′. With the removable shell  20 ,  20 ′ in place, the shield  10 ′ may be used to limit the exposure of an individual (e.g., a healthcare professional, a patient, etc.) to ionizing radiation. 
     The removable shell  20 ,  20 ′ may remain in place on the shield  10 ′ during a single use, for a predetermined number of uses (e.g., five, ten, twenty, etc.), for a predetermined period of time (e.g., one day, one week, one month, etc.) or until it becomes noticeably (e.g., by sight, by smell, etc.) soiled. Thereafter, the removable shell  20 ,  20 ′ may be removed from the shield  10 ′. In some embodiments, once the removable shell  20 ,  20 ′ has been removed from the shield  10 ′, it may be disposed of. In other embodiments, a removable shell  20 ,  20 ′ that has been removed from a shield  10 ′ may be cleaned. 
     After removing a removable shell  20 ,  20 ′ from a shield  10 ′, but prior to using the shield  10 ′ to limit an individual&#39;s exposure to ionizing radiation, the shield  10 ′ may again be covered by a clean removable shell  20 ,  20 ′. That removable shell  20 ,  20 ′ may be a different cleaned shell, the same cleaned shell, or a new disposable or reusable shell. 
     Although the foregoing description contains many specifics, these should not be construed as limiting the scope of any of the appended claims, but merely as providing information pertinent to some specific embodiments that may fall within the scopes of the appended claims. Other embodiments may also be devised which lie within the scopes of the appended claims. Features from different embodiments may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents. All additions, deletions and modifications to the disclosed embodiments that fall within the meaning and scopes of the appended claims are to be embraced thereby.