Radiant energy – Radiation controlling means – Shields
Reexamination Certificate
2002-09-09
2004-12-07
Lee, John R. (Department: 2881)
Radiant energy
Radiation controlling means
Shields
C250S516100
Reexamination Certificate
active
06828578
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates primarily to articles, including fabrics, compounds and film layers, that can protect against the hazards of exposure to radiation. In some embodiments, the fabrics and films of the present invention are used to produce relatively lightweight garments containing radiopaque materials, such as barium, bismuth, tungsten and their compounds, that are particularly suitable to protect those who are exposed to radiation (e.g., medical workers who are exposed to radiation from medical x-rays, nuclear power plant workers, soldiers etc.). Moreover, the radiopaque materials of the present invention can be incorporated into a wide variety of structures, including drywall, airplane surfaces and house sidings. The radiopaque materials of the present invention can further be formulated into paints or other coatings to impart radiation protection to a wide variety of different surfaces.
BACKGROUND OF THE INVENTION
It is very common in medicine today to use x-rays for diagnostic and therapeutic purposes. While these x-rays serve a beneficial medical purpose, they can also have harmful side effects for both the patient to whom the x-rays are directed and the medical workers who must administer x-rays on a day-to-day basis.
Other examples of how people are exposed to the harmful effects of radiation in their everyday work include the high atmosphere solar radiation which bombards commercial airliners, the radon which seeps into houses and, of course, the radiation present at nuclear power plants. In many cases, people may be exposed to health threatening doses of radiation without even realizing it.
Further, in the aftermath of the Sep. 11, 2001 terrorist attacks on the World Trade Center and the U.S. Pentagon, there has been renewed concern about the damage that could be caused by a terrorist nuclear bomb, such as a “dirty bomb” incorporating nuclear waste material. While the actual destruction caused by such a “dirty bomb” might be minor, the hazards of having radioactive material widely dispersed around an unprotected population center could be immense. If only for peace of mind, there is a great need to provide protection against such a catastrophic possibility.
There have been a number of previous attempts to mitigate the harmful effects of x-rays through the design of radiopaque protective garments. Typically, these radiopaque garments consist of a stiff material, such as rubber, impregnated by lead or some other heavy metal which is capable of blocking x-rays. Examples of lead impregnated radiopaque garments can be found in Holland's U.S. Pat. No. 3,052,799, Whittaker's U.S. Pat. No. 3,883,749, Leguillon's U.S. Pat. No. 3,045,121, Via's U.S. Pat. No. 3,569,713 and Still's U.S. Pat. No. 5,038,047.
While the lead filled prior art garments provide a good measure of protection against the harmful effects of x-rays, these prior art garments are often heavy, stiff, expensive, bulky and lacking in breathability. As such, these garments are often uncomfortable, cumbersome and restrictive. Moreover, lead, of course, is a toxic substance which must be handled very carefully and cannot be carelessly disposed of. Also, there are sterility issues with these prior art garments because they are typically too bulky and expensive to dispose of after each use. In view of lead's heavy weight, the inventors are unaware of any lead garments that protect every part of the human body.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a way to incorporate relatively lightweight radiopaque materials into many sorts of articles. In one preferred embodiment, a lightweight fabric, such as a cloth surgical mask liner or an entire surgical mask, is impregnated with a relatively lightweight radiopaque material, such as barium, bismuth, tungsten and their compounds, to impart radiopaque qualities. Examples of suitable barium, bismuth and tungsten compounds include barium sulfate, barium chloride, tungsten oxide and tungsten carbide. While these radiopaque materials may not be “lightweight” in absolute terms, they are certainly “lightweight” in relation to the radiopaque lead compounds which are used in the prior art. In other embodiments, a similar lightweight radiation protective fabric is used to produce an entire radiation protective jumpsuit, a tent, wallpaper, a liner for a commercial aircraft cabin or house sidings. Further, the radiopaque materials of the present invention can be incorporated into a paint or coating and applied to a wide variety of surfaces to thereby impart radiopaque qualities to those surfaces.
Impregnation of relatively lightweight radiopaque materials into articles can be performed in a number of ways. In one preferred embodiment, which is particularly suited for mass production, a relatively lightweight radiopaque material, such as barium, bismuth, tungsten or their compounds, is mixed with a liquid solution, emulsion or suspension of a polymer in solvent or water. The polymeric mixture is then used as a laminating adhesive or coating for one or more layers of fabric and perforated, as needed, to produce a plasticized form of lightweight radiopaque fabric. In other preferred embodiments, (1) a woven or unwoven fabric is soaked or dipped in a solution containing the relatively lightweight radiopaque material, (2) the fabric is used as a filter for a passing solution containing the relatively lightweight radiopaque material, (3) the fabric is placed in a reaction chamber between reagents that can react to form the relatively lightweight radiopaque material and (4) the fabric is created to incorporate one radiopaque chemical reagent and then exposed it to a complementary reagent to form the radiopaque material. To improve the efficiency of impregnation, an adhesive, such as Gum Arabic or Guar Gum, can be added to either the fabric or the solution of relatively lightweight radiopaque material during the impregnation process.
Besides barium, bismuth, tungsten and their compounds, other relatively lightweight radiopaque materials can be used for the present invention. These other lightweight radiopaque materials include, but are not limited to, HYPAQUETM (which is a tradename of Nycomed Corporation for Diatrizoate Meglumine Inj USP), Acetrizoate Sodium, Bunamiodyl Sodium, Diatrizoate Sodium, Ethiodized Oil, Iobenzamic Acid, Iocarmic Acid, Iocetamic Acid, Iodipamide, Iodixanol, Iodized Oil, Iodoalphionic Acid, o-Iodohippurate Sodium, Iodophthalein Sodium, Iodopyracet, Ioglycamic Acid, Iohexol, Iomeglamic Acid, Iopamidol, Iopanoic Acid, Iopentol, Iophendylate, Iophenoxic Acid, Iopromide, Iopronic Acid, Iopydol, Iopydone, Iothalamic Acid, Iotrolan, Ioversol, Ioxaglic Acid, Ioxilan, Ipodate, Meglumine Acetrizoate, Meglumine Ditrizoate Methiodal Sodium, Metrizamide, Metrizoic Acid, Phenobutiodil, Phentetiothalein Sodium, Propryliodone, Sodium Iodomethamate, Sozoiodolic Acid, Thorium Oxide and Trypanoate Sodium.
In alternative embodiments, radiopaque qualities can be imparted to garments by using a light sheet of radiopaque liner, such as aluminum, or weaving radiopaque metal or radiopaque threads into the garment. While a surgical mask is provided as one example, the principles of the invention can also be applied to a broad range of other articles including surgical hoods, hospital gowns, gloves, patient drapes, partitions, coverings, jumpsuits, uniforms, fatigues, tents, envelopes, pouches, wallpaper, liners, drywall, house sidings etc. In addition, transparent items with radiopaque qualities, such as an impregnated eye shield, can be attached to or incorporated within the radiopaque garments of the present invention.
REFERENCES:
patent: 1800051 (1931-04-01), Bianco
patent: 3030628 (1962-04-01), Crosson
patent: 3045121 (1962-07-01), Leguillon
patent: 3052799 (1962-09-01), Hollands
patent: 3164840 (1965-01-01), Reynolds
patent: 3569713 (1971-03-01), Via, Jr.
patent: 3883749 (1975-05-01), Whittaker et al.
patent: 3974104 (1976-08-01), Foster et al.
patent: 4103176 (1978-07-01), Coyle
patent: 4129524 (1978
DeMeo Ronald
Kucherovsky Joseph
Chambers Guy W.
Lee John R.
Meridian Research and Development
Smith II Johnnie L
Townsend and Townsend / and Crew LLP
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