Patent Number: 
Section: description

This application is a continuation-in-part of U.S. patent application Ser. No. 10/434,796 filed May 9, 2003. 1. Field of the Invention The present invention relates to shipping pigs for radiopharmaceuticals that use lead for radiation shielding. In particular, lead shielding is encapsulated and sealed. 2. Discussion of the Prior Art Conventional shipping pigs for radiopharmaceuticals include those that use lead for radiation shielding. The lead shielding defines a cavity to accommodate the syringe. Some conventional pigs have a removable, puncture proof, inner liner or a removable sharps container positioned within their cavity to serve as a barrier between the radiopharmaceutical syringe and the lead shielding. Such a barrier prevents contamination of the lead shielding by leaks from the radiopharmaceutical syringe, such leaks are contained by the inner liner or sharps container. A sharps container is known conventionally to be made from a puncture resistant, if not puncture-proof, hard plastic material having a tubular housing that is securable to a tubular cap in a releasable manner. Both the tubular housing and the tubular cap of the sharps container are elongated with their distal ends (to each other) closed and their proximal ends (to each other) open. The sharps container is sized to accommodate inside a syringe. It would be desirable to provide a radiopharmaceutical pig that encapsulates and seals lead shielding without the need for a removable, puncture-proof liner or a sharps container to protect the lead shielding from contamination caused by leaks from the radiopharmaceutical syringe. One aspect of the invention resides in encapsulation of an inner facing surface of a lead shield of a radiopharmaceutical pig. The inner facing surface defines a chamber in which is inserted a radiopharmaceutical syringe. The encapsulation protects the inner facing surface against contamination from leaks of the contents of the radiopharmaceutical syringe and further obviates the need for a sharps container to enclose the syringe. If desired, a non-puncture resistant, disposable housing may be inserted into the lower portion of the chamber so that the lower portion of the radiopharmaceutical syringe (with the needle) may be inserted into a cavity of the housing, thereby also doing away with the need for a sharps container. The cavity of the housing catches any leaks from the syringe that may occur to prevent the leaks from reaching regions outside the housing that the leaks could otherwise contaminate. Turning to the drawings, FIGS. 1 and 2 identify lower assembly components, namely, a lower case 1, a lower lead shield 2, a lower liner 3, and an O-ring 4, all which may be collectively considered part of a lower assembly 13. FIGS. 1 and 2 also identify upper assembly components, namely, an upper lead shield 6, an upper liner 5 and an upper case 7, all which may collectively be considered part of an upper assembly 14. The lower case 1, upper case 7, lower liner 3 and the upper liner 5 may be made of plastic, metal or a combination of each. The lower case 1 and the lower liner 3 may be secured to the lead shield so that together they encapsulate and seal the lower lead shield 2. Alternatively, the lower case 1 and the lower liner 3 may be secured to each other to contain the lower lead shield 2, but without being secured to the lower lead shield 2 itself. In either situation, the lower case 1 and lower liner 3 may be made contiguous with each other and formed from the same material, as opposed to being separate components. Likewise, the upper case 7 and the upper liner 5 may be secured to the lead shield so that together they encapsulate and seal the upper lead shield 6. Alternatively, the upper case 7 and the upper liner 5 may be secured to each other to contain the upper lead shield 6, but without being secured to the upper lead shield 6 itself. In either situation, the upper case 7 and upper liner 5 may be made contiguous with each other and formed from the same material, as opposed to being separate components. To secure the lower case 1 to the lower liner 3 and/or to the lower lead shield 2 as applicable, and to secure the upper case 7 to the upper liner 5 and/or to the upper lead shield 6, as applicable, either a securing material 15, 16 (FIGS. 4–5) or mechanical fit components 17, 18 (FIGS. 6–7) may be employed. The securing material 15, 16 (FIGS. 4–5) may be an ultrasonic seal, a heat seal, adhering material, and/or laminating material or any combination of these. The mechanical fit components 17, 18 (FIGS. 6–7) may be pressure snap rings or other types of pressure fit components, such as screw locks, clamps or conventional mechanical fasteners. The O-ring 4, which may be made of neoprene or other elastomer, is securely attached into a groove 8, such as with glue or epoxy. The O-ring 4 seals the lower liner 3 to the upper liner 5 as the upper assembly 14 may be screwed onto the lower assembly 13 using the threads 9. Each of the lower liner 3 and the upper liner 5 may have outwardly directed flange surfaces that sandwich the O-ring 4 between them to seal a chamber defined by the lower and upper liners 3, 5. The threads 9 may be triple start threaded to reduce an amount of turns needed to screw the two assemblies 13, 14 together. In addition, the lower case 1 has flats 11 that are molded to prevent the lower assembly 13 from rolling on a flat surface. There may be a configuration with at least one corner such as a hexagon shape 12 molded onto the bottom of the lower case 1 such that the hexagon shape 12 can be secured in a hexagon shaped hole or recess. This way the upper assembly 14 can be screwed to, or unscrewed from, the lower assembly 13 without the user holding onto the lower assembly. This greatly reduces the amount and duration of hand exposure to radiation, because the user no longer needs to hold onto the lower assembly during the screwing and unscrewing operations. The syringe 10 contains a radiopharmaceutical and is placed into the lower liner 3 before the two halves of the upper and lower cases 1, 7 are screwed together by engaging thread connections. After the two halves have been screwed together, the syringe 10 is shipped filled within the two halves to a site. After arrival at the site, the syringe is removed from the two halves and used to administer the radiopharmaceutical from the syringe. When done, the empty syringe may be reinserted into the pig and then shipped back to the supplier for further handling. Otherwise, the empty syringe may be placed into a conventional, lead shielded container (not shown) for future disposal in accordance with government regulations for safe disposal of spent radiopharmaceutical syringes. The two lead shields 2, 6 have edges that face each other that are configured to overlap and engage each other so as to completely shield against penetration of radiation at the joint between the two lead shields 2, 6. Thus, lower lead shield 2 may have a tubular projection in the edge that complements a further tubular projection in the edge of the upper lead shield 6 and is of a reduced diameter relative to that of the further tubular projection. The lower lead shield 2 may have a lower projection that fits within a complementary recess inside at the base of the lower case 1. As a result of encapsulating, the lower and upper lead shields 2, 6 are sealed and thereby protected by the lower and upper liners 3, 5 against contamination from any radiopharmaceutical remnants from the syringe 10 and against exposing the lead shields to cleansing fluids such as water when cleaning them. The syringe 10 may be entirely free of any sharps container surrounding it, because the lower and upper liners 3, 5 obviate the need for it. Indeed, a sharps container would not need to be used in the radiopharmaceutical pig of the present invention to provide sufficient protection of the lead shields against contamination by the discharge of any remnants from within the syringe 10, because the encapsulation provides sufficient protection. The lower and upper liners 3, 5 themselves may be formed of an encapsulating material that adheres or otherwise clings to secure itself to the lead shield to which it is in contact, such as when subjected to a sufficient amount of heat. Turning to FIGS. 4 and 5, the lower shield 2 does not have to be secured to either the lower case 1 or to the lower liner 3. Instead, the lower liner 3 is secured directly to the outer case 1 around a periphery (contact diameter) with the securing material 15. Likewise, the upper shield 6 does not have be secured to either the upper case 7 or to the upper liner 5. Instead, the upper liner 5 may be secured to the upper case 7 about a periphery (contact diameter) with the securing material 16. The lower shield 2 and the upper shield 6 are thereby held in place. Turning to FIGS. 6 and 7, the lower liner 3 may be mechanically fastened to the lower case 1 using a mechanical fit component 17, such as snap rings, screw locks, clamps or conventional mechanical fasteners. The lead shield 2 need not be adhered to anything. Likewise, the upper liner 5 is mechanically fastened to the upper case 7 using a mechanical fit component 18, such as snap rings, screw locks, clamps or conventional mechanical fasteners. The lead shield 6 need not be adhered to anything. Turning to FIG. 8, a flexible, removable, disposable housing 19 is shown for the lower half of the pig. The housing 19 is not puncture-resistant, but would still serve to keep the pig clean, capturing anything that may come out of the syringe 10, because the housing 19 has a closed bottom end. The housing 19 is positioned to be out of contact with the tip of the needle of the syringe while the syringe is within the pig. The housing 19 may be made of any non-puncture-resistant material, such as a soft plastic. In accordance with the invention, sufficient clearance is provided within the cavity defined by the housing to accommodate insertion of the syringe so that the tip of the needle of the syringe will not contact the housing during insertion of same into the lower portion of the cavity and by configuring the upper and lower halves of the radiopharmaceutical pig to clamp outward flanges of the syringe between them so as to maintain the position of the syringe within the cavity in a stable manner during transport. Preferably, the clearance within the lower portion of the cavity is longer than the tip of the needle can reach when the lower portion of the syringe is fully inserted and is wider than the diameter of the body of the syringe and thus many times wider than the diameter of the needle. The housing 19 is elongated with a mouth at one end sized to accommodate insertion of the needle of the radiopharmaceutical syringe through the mouth and preferably accommodate the lower half of the syringe, and an opposite end that is closed to contain any leaks from the radiopharmaceutical syringe. If desired, a puncture resistant platform (not shown) may be inserted within the housing 19 to rest at the opposite end to prevent the tip of the needle from penetrating to reach the housing itself. A cap made of the same non-puncture resistant material as the housing 19 may likewise be used to accommodate the upper half of the syringe so that the entire syringe with attached needed is contained within confines of the housing 19 and the cap to prevent leaks of contents of the syringe from reaching areas of the pig beyond the housing. Such a cap and housing 19 serves the same role as a conventional sharps container, but would not be made from material that is puncture-resistant as is the sharps container and thus differs in that respect. The housing 19 and cap would be disposed of after use, but would serve the purpose of preventing contamination outside the housing and cap. While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be understood that various changes and modifications may be made without departing from the scope of the present invention.