WO2009039074A1

WO2009039074A1 - Radioisotope-generator valve

Info

Publication number: WO2009039074A1
Application number: PCT/US2008/076487
Authority: WO
Inventors: Duane L. Horton; Kevin R. Martz; David W. Pipes; Andrew D. Speth; William A. Hagen
Original assignee: Mallinckrodt Inc
Current assignee: Mallinckrodt Inc
Priority date: 2007-09-19
Filing date: 2008-09-16
Publication date: 2009-03-26
Anticipated expiration: 2010-03-19

Abstract

Systems, methods, and devices are disclosed, including a generator for separating radioisotopes. In some embodiments, the generator includes a radioisotope generator (22) having an aperture (48), a resilient member (58) connected to the radioisotope generator, and a sealing member (42) connected to the radioisotope generator by the resilient member. The sealing member may be configured to obstruct the aperture depending on whether the resilient member is biased.

Description

RADIOISOTOPE-GENERATOR VALVE

FIELD OF THE INVENTION

[0001] The invention relates generally to radioisotope generators and, more specifically, to radioisotope- generator valves.

BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] In the field of nuclear medicine, health-care professionals often diagnose and treat patients with radioactive material. Typically, the health-care professional injects a patient with a small dose of the radioactive material, which once in the patient's body, concentrates in certain organs or regions. Some radioactive materials naturally concentrate in a particular tissue: for example, iodine concentrates in the thyroid. Examples of radioactive material used for nuclear medicine include technetium-99m, indium-111 , and strontium-89. Frequentiy, the radioactive material is combined with a tagging or organ-seeking agent, which targets the radioactive material for the desired organ or biologic region of the patient. These radioactive materials, alone or in combination with a tagging agent, are typically referred to as radiopharmaceuticals. At relatively low doses, a radiation imaging system (e.g., a gamma camera) may be used to image the organ or biological region that collects the radiopharmaceutical. Irregularities in the image often indicate a pathology, such as cancer. Higher doses of the radiopharmaceutical may treat pathologic tissue, such as cancer ceils.

[0004] Many radiopharmaceuticals decay rapidly, so manufacturing and using them is a time-sensitive process. In some applications, shortty before use, the radiopharmaceuticai is drawn from a radioisotope generator by eluting, or separating, the radiopharmaceuticai from a more-stable radioactive material that decays into the desired radiopharmaceutical, e.g., molybdenum-99, as it decays, produces technetlum-99m. During this process, the desired radioactive material is carried from the generator by a solvent, referred to as an eluant, and the radioisotope generator outputs a radioactive solution, referred to as an eluate, which is typically received in a viai connected to the output of the radioisotope generator.

[0005] The eluate, if not properly contained, can cause problems. When the elution ends, and the receiving vial is removed, the radioisotope generator could still carry eluate, which could leak from the output. If radioactive solution escapes from the radioisotope generator, it could be expensive to clean and inconvenience people who wish to avoid the spill. SUMMARY

[0006] Certain aspects commensurate in scope with the originally claimed invention are set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.

[0007] In accordance with a first aspect of the present invention, there is provided a generator for separating radioisotopes. In certain embodiments, the generator includes a radioisotope generator having an aperture, a resilient member (such as a spring) connected to the radioisotope generator, and a sealing member (such as a rubber body) connected, either directly or indirectly, to the radioisotope generator via the resilient member. The sealing member obstructs, e.g., seals, the aperture depending on whether the resilient member is biased.

[0008] In accordance with a second aspect of the present invention, there is provided a method for generating a radioisotope. The method includes automatically closing a fluid port (e.g., an aperture of a needle) of a radioisotope generator in response to removal of a vial, such as an eluate receptacle or an eluant source container.

[0009] In accordance with a third aspect of the present invention, there is provided a radioisotope- elution system that includes a generator, radiation shielding disposed at least partially about the generator, a fluid port fluidly coupled to the generator, and a valve configured to obstruct the outlet based on whether a container is connected to the generator,

[0010] In accordance with a fourth aspect of the present invention, there is provided a valve for an elution system. In some embodiments the valve includes a needle having an aperture, a sealing member, and a resilient member connected to the needle and the sealing member. The resilient member obstructs the aperture with the sealing member depending on whether a container is connected to the needle.

[0011] Various refinements exist of the features noted above in relation to the various aspects of the present invention. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above- described aspects of the present invention alone or in any combination. Again, the brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of the present invention without limitation to the claimed subject matter.

BRIEF DESCRIPTION OF THE FIGURES

[0012] Various features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:

[0013] FIG. 1 is an elevation view of a radioisotope-elution system;

[0014] FIG.2 is a cross-section of the radioisotope-elution system of FIG. 1; [0015] FIGS. 3 and 4 are exploded views of the radtoisotope-elution system of FIG. 1 from different perspectives;

[0016] FIG. 5 is a top-perspective view of the radioisotope-elution system of FIG. 1 ;

[0017] FIG.6 is a perspective view of a valve;

[0018] FIGS.7 and 8 are cross-sections of the valve of FIG.6 closed and open, respectively;

[0019] FIG.9 is a perspective view of another valve;

[0020] FIG. 10 is a perspective view of a plunger of the valve of FiG.9;

[0021] FIG. 11 is a perspective view of an upper body of the valve of FIG. 9;

[0022] FiGS. 12 and 13 are cross-sections of the valve of FIG.9 dosed and open, respectively;

[0023] FIG. 14 is a perspective view of a third valve;

[0024] FIGS. 15 and 16 are cross-sections of the valve of FIG.14 closed and open, respectively;

[0025] FIG. 17 is a flow chart of a nuclear medicine process;

[0026] FIG. 18 is a diagram of a system for loading a syringe with a radioisotope; and

[0027] FIG. 19 is a diagram of a nuclear-imaging system.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0028] One or more specific embodiments of the present invention will be described below, In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

[0029] When introducing elements of various embodiments, the articles "a," "an," "the," "said," and the like mean that there are one or more of the elements. The terms "comprising," "including," "having," and the like are inclusive and mean that there may be additional elements other than the listed elements. Moreover, the use of "top," "bottom," "above," "below," and variations of these terms does not require any particular orientation of the components relative to some extrinsic reference, e.g., gravity. As used herein, the term "coupled" refers to the condition of being directly or indirectly connected or in contact. Additionally, the phrase "in fluid communication" or "fluidly coupled" indicates that fluid or fluid pressure may be transmitted from one object to another. Similarly, the phrases "in thermal communication" and "thermally coupled" indicate that heat may be transferred from one object to another. As used herein, the word "exemplary" means "an example" and not necessarily a preferred embodiment.

[0030] FIG. 1 is an elevation view of an exemplary elution system 10, which includes an auxiliary shield 12 and a shielded elution assembly 14. The illustrated elution system of 10 also has a valve 15, several examples of which are described below, that tends to mitigate some of the problems with conventional elution systems. As described below, in some embodiments, the valve 15 closes (automatically or manually) an output of the elution system 10 in response to a vial being removed from the output. Consequently, in some embodiments, the elution system 10 is believed to be less likely to leak eluate after an elution. Examples of the valve 15 are described further below, after describing other components of the elution system 10.

[0031] As mentioned, the illustrated etution system 10 has an auxiliary shield 12, which in this embodiment, includes a base 16, a lid 18, and a plurality of generally step-shaped, tiered modular rings 20 disposed one over the other between the base 16 and the lid 18 (see FIG. 2). Substantially all or part of the illustrated auxiliary shield 12 may be made of, or include, one or more radiation-shielding materials, such as lead, tungsten, depleted uranium, or tungsten-impregnated plastic. One or more of the components of the auxiliary shield 12 may be lined with, powder coated on, and/or embedded in other materials, such as a polymer. For instance, in some embodiments, at least a portion (e.g., a majority, or a substantial entirety) of the lid 18 of the assembly 12 may be over-molded with polycarbonate resin (or other polymer). Embedding or over molding the shielding materials may enhance durability and/or facilitate formation of components with smaller dimensional tolerances than components made entirely out of shielding materials. Moreover, the modular aspect of the rings 20 may tend to enhance adjustment of the height of the auxiliary shield 12, and the step-shaped configuration may tend to contain some radiation that might otherwise escape through an interface between the rings 20. While FIGS. 1 and 2 depict one example of an auxiliary shield 12, it should be noted that, as with the other examples described herein, other types or configurations may be employed.

[0032] FIG.2 is a cross-section, elevation view that illustrates additional features of the elution system 10, including a radioisotope generator 22 (hereinafter, generator), an eluant source 24, and an eluate receptacle 26 disposed within the auxiliary shield 12. Herein, the term "eluant source" refers to a container (e.g., a vial or a conduit) that has or had an elution source fluid (e.g., oxidant-free, physiologic saline) disposed therein. In contrast, an "eluate receptacle" refers to a container that receives the eluate. As illustrated, the eluant source 24 is coupled to the generator 22 via one or more inlet needles 28 (e.g., a pair of hollow needles, one of which vents, and one of which is in direct fluid communication with the generator 22), while the eluate receptacle 26 is coupled to the generator 22 via one or more outlet needles 30 (e.g., a single-hollow needle). When coupled to the generator 22, the eluant source 24 and eluate receptacle 26 may be said to be in fluid communication with the generator 22 (e.g., associated in a manner that enables fluid to flow from the eluant source 24 to eluate receptacle 26, through the generator 22). The eluate receptacle 26 is disposed inside an elution shield 32 of the shielded elution assembly 14. The elution shield 32 may be made of lead, tungsten, tungsten impregnated plastic and/or another suitable radiation-shielding material.

[0033] Internally, the illustrated generator 22 includes an elution column configured to separate and output a desired radioisotope. Certain medically-useful radioisotopes have relatively short half-lives (e.g., technetium-99m (99mTc) has a half-life of approximately 6 hours). To potentially expand the useful life of the generator 22, the elution column may include a more-stable radioisotope that decays into the desired radioisotope (e.g., molybdenum-99 (99Mo) has a half-life of approximately 66 hours and decays into 99mTc). As the desired radioisotope is needed, it may be separated from the more stable radioisotope with an elution process, two examples of which are explained below. The generator 22 may also include shielding configured to diminish radiation, and tubing to conduct fluids into and out of the elution column.

[0034] In operation, an eluant inside the eiuant source 24 is circulated through the inlet needle 28, through the generator 22 (including the elution column), and out through the outlet needle 30, into the eluate receptacle 26. This circulation of the eluant washes out (e.g., extracts) a radioactive material, such as a radioisotope, from the generator 22. For example, one embodiment of the generator 22 includes an internal radiation shield (e.g., lead shell) that encloses a radioactive parent, such as molybdenum-99, affixed or otherwise coupled to the surface of beads of alumina or a resin exchange column. Inside the generator 22, the parent molybdenum-99 decays, with a half-life of about 66 hours, into metastable technetium-99m. The daughter radioisotope, e.g., technetium-99m, is generally held less tightly than the parent radioisotope, e.g., molybdenum-99, within the generator 22. Accordingly, the daughter radioisotope, e.g., technetium-99m, can be extracted with a suitable eluant, such as an oxidant-free, physiologic saline solution. Upon collecting a desired amount (e.g., desired number of doses) of the daughter radioisotope within the eluate receptacle 26, the elution assembly 14 can be removed from the radtotsotope-elution system 10. As discussed in further detail below, the extracted daughter radioisotope can then, if desired, be combined with a tagging agent to diagnose or treat a patient (e.g., in a nuclear-medicine facility).

[0035] The illustrated elution system 10 is configured to perform two types of elutions: a dry elution and a wet elution, examples of both of which are described below. To perform a dry elution, prior to the elution, the eluant receptacle 26 is substantially evacuated, and the eluant source 24 is filled with a volume of saline that generally corresponds to the desired volume of radioisotope solution. During a dry elution, the vacuum in the eluant receptacle 26 draws eluant from the eluant source 24, through the generator 22, and into the eluant receptacle 26. After substantially all of the eluant has been drawn from the eluant source 24, a remaining vacuum in the eluant receptacle 26 draws air, or other non-eluant fluid, through the generator 22, thereby removing eluant that might otherwise remain in the generator 22. Air or other appropriate fluids may flow into the eluant source 24 through the inlet vent needle 28 and into the generator 22 through the other inlet needle 28, The volume and pressure of the eluant receptacle 26 may be selected such that substantially all of the eiuant is drawn out of the generator 22 by the end of an elution. In contrast, a wet elution potentially leaves eluant in the generator 22. The eluant source 24 is generally larger than the eluant receptacle 26, so an eluant source 24 may supply multiple elutions that refill the eluant receptacle 26 multiple times. Because the eluant source 24 and the generator 22 are not necessarily evacuated by the eluant receptacle 26, after a wet elution, residual eluant may remain in the generator 22.

[0036] To reduce the likelihood of residual eluant leaking, the elution system 10 may include the valve 15. The position of the valve 15, in the presently described embodiment, is clearly illustrated in FlG.5, which is a top-perspective view of the elution system 10. As explained below, the valve 15 may be configured to automatically or manually seal a passage in fluid communication with the outlet of the elution system 10, e.g., the outlet needle 30. In some embodiments, the valve 15 is configured to automatically seal the passage in response to the removal of the eluate receptacle 26 and automatically unseal the passage in response to the presence of the eluate receptacle 26. Below, embodiments of the valve 15 are described by way of three examples.

[0037] FIG.6 depicts a valve 34 that exemplifies the valve 15 illustrated in the previous figures, in this embodiment, the valve 34 includes the outlet needle 30, a body 36, an upstream passage 38, a needle spacer 40, a sealing member 42, a sealing-member support 44, and an alignment rail 46. Interior components are described below in reference to FIGS.7 and 8, which illustrate cross-sections of the valve 34 in the open and closed positions. The illustrated body 36 defines a generally circular, right-cylindrical volume that is generally concentric about the outlet needle 30. The body 36 may be injection molded or otherwise formed from plastic or other appropriate materials. The upstream passage 38 extends from, and is in fluid communication with, the needle 30 and may include an offsetting portion 45 that aligns with other components of the generator 22. The needle spacer 40, in this embodiment, extends from a base 49 of the body 36 in a direction that is generally perpendicular to the outlet needle 30. The needle spacer 40 may be made of plastic, and may include an aperture or channel 47 near its distal end to hold the inlet needles 28 in generally fixed relation to the outlet needle 30, e.g., generally parallel and at a generally fixed distance.

[0038] In this embodiment, the seating member 42 is held by the seaiing-member support 44, e.g., by an interference fit or an adhesive, and is generally concentric about the outlet needle 30. The sealing member 42 may be made of or include a resilient material, such as an elastomer, e.g., rubber. In this embodiment, the sealing member 42 defines a generally circular, right-cylindrical volume and includes an aperture 48 in which the outlet needle 30 is slideably disposed. For example, by applying an appropriate amount of force to the sealing member 42 in a direction generally parallel to the outlet needle 30, the sealing member 42 may be slid along the outlet needle 30, as described below. In some embodiments, the seating member 42 may be described as having a single degree of freedom relative to the outlet needle 30. To potentially enhance sealing, the aperture 48, in an unbiased state, may be smaller than an outer diameter of the outlet needle 30, so that the sealing member 42 deforms around the outlet needle 30 and biases the outlet needle 30 in a direction generally perpendicular to the length of the outlet needle 30, e.g., concentrically.

[0039] In the illustrated embodiment, the sealing-member support 44 is slideably disposed in the body 36 and is affixed to the sealing member 42, so that like the sealing member 42, it has a single degree of freedom relative to both the outlet needle 30 and the body 36. The presently described sealing-member support 44 is generally concentric about the outlet needle 30 and is generally rotationally symmetric. To hold the sealing member 42, the sealing-member support 44 includes a circular, right-cylindrical receptacle 50 in which the sealing member 42 is partially or entirely disposed.

[0040] The alignment rail 46 may be affixed to the body 36, e.g., it may be integrally formed as a single part with the body 36, or it may be adhered or interlocked with the body 36. tn the illustrated embodiment, the alignment rail 46 has a generally uniform cross-section in the direction of the outlet needle 30 and is positioned on the body 36 adjacent the needle spacer 40.

[0041] FIG. 7 illustrates a cross-section of the valve 34 in the closed position. In addition to those features discussed above, the illustrated valve 34 includes the following features: a needle aperture 52; a sealing- member restraint 54; an interior 56; a resilient member 58; an upper, resiiient-member mount 60; a lower, resilient- member mount 62; and a needle passage 64.

[0042] In the illustrated embodiment, the needle aperture 52 is a hole in the side of the needle 30 and is positioned on the needle 30 such that when the valve 34 is in the closed position, the sealing member 42 covers the needle aperture 52. Consequently, in some embodiments, the sealing member 42 may tend to prevent fluid, e.g. liquid, from exiting the needle 30 via the needle aperture 52. The illustrated needle aperture 52 is offset from the end of the needle 30 and is not at the end of the needle 30. In some embodiments there needle 30 includes more than one needle apertures 52 disposed at substantially the same offset or different offsets along the needle 30. In some embodiments, these needle apertures 52 may be the same or different sizes.

[0043] The illustrated sealing-member restraint 54 is a ring-shaped ledge that extends radially inward from the body 36 and constrains the movement of the sealing member 42 and sealing-member support 44. To this end, the sealing-member restraint 54 may overlap and contact the sealing-member support 44 when the valve 34 is in the closed position. In some embodiments, when closed, the sealing-member support 44 is biased against the sealing-member restraint 54 by the resilient member 44.

[0044] The illustrated resilient member 58 is a helical-compression spring disposed in the interior 56 of the body 36. In this embodiment, the resilient member 58 applies a force to the sealing-member support 44 in the direction of the outlet needle 30 toward the needle aperture 52. The illustrated resilient member 58 is affixed to the upper, resilient-member mount 60 and the lower, resilient-member mount 62 by an interference fit. Other embodiments may include other types of resilient members, such as a cantilevered beam, a wave spring, or an elastomer member, or other types of devices configured to move the sealing member 42, such as a piston in a cylinder (e.g., a pneumatic device), opposing magnets, electromagnets, a motor (e.g., a linear motor), a shape- memory alloy, a thermally-expanding member, or a petzo-electric device.

[0045] The needle passage 64 of the presently described embodiment extends from the interior 56, through the base 49, to the exterior of the body 36. This needle passage 64 includes a bend to accommodate the offset portion 45 of the upstream passage 38.

[0046] The operation of the valve 34 is illustrated by a comparison of FIG.7, which depicts the valve 34 in the closed position, to FIG.8, which depicts the valve 34 in the open position. To open the presently described embodiment, the eluate receptacle 26 is positioned proximate to, e.g., in contact with, the valve 34 and is pushed against the sealing-member support 44, as indicated by arrow 70 in FlG. 8. In this embodiment, the eluate receptacle 26 is a vial including a stopper 66 made of a resilient material, such as rubber, that seals an interior 68, which may be at a sub-atmospheric pressure, e.g., a vacuum or a pressure approaching a vacuum.

[0047] As depicted by FIG. 8, the eluate receptacle 26 is moved in direction 70 generally parallel to the outlet needle 30, until a distal end 72 displaces the sealing member 42 and sealing-member support 44 a distance 74. At substantially the same time, a downward force from the eluate receptacle 26 further biases, e.g., compresses, the resilient member 58, and the sealing member 42 and sealing-member support 44 translate, e.g., move along a substantially linear path with or without rotating. As the sealing-member support 44 moves, the sealing member 42 slides over the needle 30, and the perimeter of the sealing-member support 44 is guided by, e.g., slides against, the interior 56 of the body 36. As the eluate receptacle 26 moves, the needle 30 pierces the stopper 66, and the stopper 66 translates past the needle aperture 52, thereby placing the interior 68 of the eluate receptacle 26 in fluid communication with the upstream passage 38 and the generator 22. The vacuum (or relative pressure difference, e.g., the eluant source 24 may be pressurized) may drive eluate through the generator 22 and into the eluate receptacle 26.

[0048] After the desired amount of eluate is received, the eluate receptacle 26 is removed by reversing the process described above. As the eluate receptacle 26 translates in a direction opposite the arrow 70, the resilient member 58 relaxes, driving the sealing member 42 and sealing member support 44 back along the outlet needle 30 until the sealing member support 44 contacts the sealing-member restraint 54. At this point, the sealing member 42 covers the needle aperture 52, thereby closing the valve 34. Thus, the illustrated valve 34 automatically closes in response to removal of the eluate receptacle 26, which is believed to reduce the likelihood of residual eluate leaking from the generator 22.

[0049] The illustrated vaive 34 obstructs, e.g., seals, the outlet of the elution system 10 near the needle aperture 52, e.g., at the needle aperture. This is believed to reduce the volume of eluate upstream from the obstruction. Embodiments may obstruct or seal the outlet of the elution system within the needle 30, within the upstream passage 38, e.g., adjacent the needle 30, or between the needle 30 and the generator 22.

[0050] FIG. 9 illustrates another example of a valve 76, which in this embodiment, includes the outlet needle 30 and upstream passage 38, along with a plunger 78, an upper body 79, and a lower body 80. The upstream passage 38 is generally aligned with, and parallel to, both the outlet needle 30 and a central axis 81, but in other embodiments, the upstream passage 38 may have a bend similar to the offsetting portion 45 in FIGS.6-8. As explained below, the valve 76 may respond to the approach of an eluate receptacle 26 by opening the valve 76. As the eluate receptacle 26 approaches, it may displace the plunger 78, which opens the vaive 76, and as the eluate receptacle 26 is removed, the plunger 78 may return to its original position and internal components described below may close the valve 76.

[0051] The plunger 78 is illustrated in greater detail in FIG, 10. !n this embodiment, the plunger 78 includes a contact plate 82, an extension 84, a needle passage 86, and legs 88, 90, and 92. The contact plate 82, the extension 84, the needle passage 86, and each of the legs 88, 90, and 92, in this embodiment, each define a generally circular, right-cylindrical volume. The illustrated plunger 78 includes three legs 88, 90, and 92 that are generally equally distributed about the central axis 81 and extended generally parallel to the central axis 81. Other embodiments may include more or fewer legs or legs of a different shape. The plunger 78 may be made of a single body of plastic or other appropriate materials.

[0052] The top of the upper body 79 is illustrated in FIG. 11. In this embodiment, the upper body 79 includes a recess 94, a needle passage 96, and leg apertures 98, 100, and 102. Each of these features may define a generally circular, right-cylindrical volume that extends generally parallel to the central axis 81 , The recess 94 and needle passage 96 are generally concentric about the central axis 81, and the leg apertures 98, 100, and 102 are complementary to the legs 88, 90, and 92 of the plunger 78. In this embodiment, the leg apertures 98, 100, and 102 are sized to form a sliding seal with the legs 88, 90, and 92 so that the plunger 78 can translate along the central axis 81 while the leg apertures 98, 100, and 102 tend to prevent fluid from flowing past the legs 88, 90, and 92. In this embodiment, the recess 94 is substantially smaller than the contact plate 82, but in other embodiments, the contact plate 82 may be smaller or about the same size as the recess 94.

[0053] FlG. 12 illustrates a cross-section of the valve 76 in the dosed position. As illustrated, in addition to those features described above, the illustrated valve 76 includes an upper-static seal 104, a movable seal 106, a leg-contact plate 108, a resilient member 110, and a lower-static seal 112 disposed in an interior 114. The upper-static seal 104 and lower-static seal 112 may have a generally tubular shape with a central passage that is in fluid communication with the outlet needle 30 and the upstream passage 38, respectively. In this embodiment, the movable seal 106 is affixed to the leg-contact plate 108, and the leg-contact plate 108 and movable seal 106 are, in the presently described closed position, biased against the upper-static seal 104 by the resilient member 110. The illustrated leg-contact plate 108 contacts the distal ends of the legs 88, 90, and 92 and may include recesses for receiving the legs 88, 90, and 92. In this embodiment, both the outlet needle 30 and the upstream passage 38 include a flared portion 116 and 118 in sealing contact with the upper-static seal 104 and the lower-static seal 112, respectively. The upper-static seal 104, the movable seal 106, and the lower-static seal 112 may be made from an elastomer, such as rubber, and the resilient member 110 may be a helical, compression spring or other device configured to drive movement, such as those described above. In this embodiment, the outlet needle 30 includes a needle aperture 52 at its tip.

[0054] FIG. 13 illustrates the valve 76 in the open position. To open the illustrated valve 76, the eluate receptacle 26 is moved in the direction 70, which is generally parallel to the centra! axis 81 , and its distal end 72 pushes the contact plate 82 downward. As of the plunger 78 translates, the dimension 120 is reduced, and the legs 88, 90, and 92 slide through the leg apertures 98, 100, and 102 and push against the leg-contact plate 108. As the leg-contact plate 108 moves in response to the force from the legs 88, 90, and 92, it carries the movable seal 106 away from the upper-static seal 104 and biases, or further biases, the resilient member 110. The movement of the movable seal 106 creates a gap between the moveable seal 106 and the upper-static seal 104 through which eluate may flow, as illustrated by flow path 122. In this embodiment, the eluate flows out of the upstream passage 38, into the interior 114, around the sides of the leg-contact plate 108, around the legs 88, 90, and 92, through the gap between the movable sea! 106 and the upper-static seal 104, through the outlet needle 30, and into the interior 68 the eluate receptacle 26.

[0055] When the eluate receptacle 26 is removed, e.g. after receiving a desired number of doses, the valve 76 may respond by closing. In this situation, the resilient member 110 may relax and drive the leg-contact plate 108 upward, or toward the upper-static seal 104, which may close the gap between the movable seal 106 and the upper-static seal 104. The movement of the leg-contact plate 108 may also drive the plunger 78 upward via the legs 88, 90, and 92. As the legs 88, 90, and 92 slide through the leg apertures 98, 100, and 102, the interior 114 may remained substantially sealed. The resilient member 110 may drive the valve 76 back to the closed state illustrated by FlG. 12. In this position, the movable seal 106 may be biased against the upper-static seal 104, thereby reducing the likelihood of eluate escaping from the outlet needle 30. Thus, again, the valve opens and closes fluid flow upstream from the aperture 52 of the needle 30. [0056] FlG. 14 illustrates a third example of a valve 124. The illustrated valve 124 inciudes an upper body 126, a lower body 128, and a sealing member 130. The upper body 126 defines a generally circular, right- cylindrical volume that is concentric about a central axis 132. in this embodiment, the upper body 132 is slideably connected, e.g., connected in a manner that allows for a single degree of freedom, to the lower body 128, which includes a needle spacer 40 and a guide 134 into which the upper body 126 slides, as described below. The illustrated sealing member 30 is disposed in the upper body 130 opposite the lower body 128 and may be made out of or include a resilient material, such as, an elastomer, e.g., rubber.

[0057] FIG. 15 illustrates a cross-section of the valve 124 in the closed position. In this embodiment, the upper body 126 includes an aperture 136, a contact ring 137, and a sheath 138. The illustrated aperture 136 envelopes part of sealing member 130 and substantially all of a distal portion of the outlet needle 30, at least when the valve 124 is closed. The contact ring 137, in this embodiment, is a ledge that extends radially inward from the sides of the upper body 126 and defines a passage that is smaller than or roughly the same size as the aperture 136. The illustrated sheath 138 is a thinner portion of the upper body 126 that is at a distal end of the upper body 126 opposite the sealing member 130,

[0058] The presently described sealing member 130 includes an aperture 139 that is generally concentric to the central axis 132 and is generally aligned with the outlet needle 30. The aperture 139 may have a generally uniform diameter along its length or it may vary in diameter, e.g., a distal portion may be narrower than the portion closer to the tip of the outlet needle 30. The illustrated sealing member 130 covers the needle aperture 52 at the tip of the outlet needle 30 and, in some embodiments, concentrically biases the tip of the outlet needle 30.

[0059] In this embodiment, the guide 134 includes a recess 140 through which the upper body 126 slides and a needle support 142. inside both the sheath 138 and the recess 140 is a resilient member 144, which in this embodiment is a helical, compression spring, but in other embodiments may include one or more devices configured to generate movement, as described above. The needle support 142 may define a generally circular, right-cylindrical volume that is concentric to the central axis 132, and it may be disposed between the resilient member 144 and side walls 145 of the guide 134. The needle support 142 may be complementary to contact ring 137 and, in some embodiments, may form a sliding seal with the contact ring 137. The bottom of the resilient member 144 may be biased between, or rest against, the contact ring 137 and a base 147 of the guide 134 that extends between the side walls 145 and the needle support 142.

[0060] FIG. 16 illustrates the valve 124 in the open position. As with the previously described embodiments, the valve 124 is opened by the approach of the eluate receptacle 26. When the eluate receptacle 26 is moved in the direction 70, along the central axis 132, the stopper 66 pushes the upper body 126 into the guide 134, and as fie upper body 126 and the sealing member 130 retreat in response, the contact ring 137 of the upper body 126 biases, e.g. compresses, or further biases resilient member 144. As the upper body 126 moves, the sealing member 130 slides over the outlet needle 30, and the outlet needle 30 is exposed and pierces the stopper 66 of the eluate receptacle 26.

[0061] In a similar fashion, the illustrated valve 124 automatically closes as the eluate receptacle 26 is withdrawn. Without the stopper 66 pressing against the sealing member 130, the resilient member 144 relaxes and drives the upper body 126 out of the recess 140. When the upper body 126 reaches the position illustrated by FIG. 15, the sealing member 130 may cover the needle aperture 52, thereby substantially or completely sealing the outlet needle 30. Thus, when the eluate receptacle 26 is removed, the sealing member 130 may tend to prevent eluate from leaking through the outlet needle 30.

[0062] Although the previously described valves 15 sea! a passage to the eluate receptacle 26, other embodiments may include a valve 15 to seal passages to other containers. For instance, the valve 15 may seal a passage to the eluant source 24. In some embodiments, two valves 15 may seal two passages, one to the eluate receptacle 26 and one to the eluant source 24.

[0063] FIG. 17 is a flowchart illustrating an exemplary nuclear medicine process that uses the radioactive isotope produced by the previously discussed radioisotope-elution systems 10. As illustrated, the process 162 begins by providing a radioactive isotope for nuclear medicine at block 164. For example, block 164 may include eluting technetium-99m from the generator 22 illustrated and described in detail above. At block 166, the process 162 proceeds by providing a tagging agent (e.g., an epitope or other appropriate biological directing moiety) adapted to target the radioisotope for a specific portion, e.g., an organ, of a patient. At block 168, the process 162 then proceeds by combining the radioactive isotope with the tagging agent to provide a radiopharmaceutical for nuclear medicine. In certain embodiments, the radioactive isotope may have natural tendencies to concentrate toward a particular organ or tissue and, thus, the radioactive isotope may be characterized as a radiopharmaceutical without adding any supplemental tagging agent. At block 170, the process 162 then may proceed by extracting one or more doses of the radiopharmaceutical into a syringe or another container, such as a container suitable for administering the radiopharmaceutical to a patient in a nuclear medicine facility or hospital. At block 172, the process 162 proceeds by injecting or generally administering a dose of the radiopharmaceutical into a patient. After a pre-selected time, the process 162 proceeds by detecting/imaging the radiopharmaceutical tagged to the patient's organ or tissue (block 174). For example, block 174 may include using a gamma camera or other radiographic imaging device to detect the radiopharmaceutical disposed on or in or bound to tissue of a brain, a heart, a liver, a tumor, a cancerous tissue, or various other organs or diseased tissue.

[0064] FIG. 18 is a block diagram of an exemplary system 176 for providing a syringe having a radiopharmaceutical disposed therein for use in a nuclear medicine application. As illustrated, the system 176 includes the radioisotope-elution system 10. The system 176 also includes a radiopharmaceutical production system 178, which functions to combine a radioisotope 180 (e.g., technetium-99m solution acquired through use of the radioisotope-elution system 10) with a tagging agent 182. In some embodiment, this radiopharmaceutical production system 178 may refer to or include what are known in the art as "kits" (e.g., Technescan® kit for preparation of a diagnostic radiopharmaceutical). Again, the tagging agent may include a variety of substances that are attracted to or targeted for a particular portion (e.g., organ, tissue, tumor, cancer, etc.) of the patient. As a result, the radiopharmaceutical production system 178 produces or may be utilized to produce a radiopharmaceutical including the radioisotope 180 and the tagging agent 182, as indicated by block 184. The illustrated system 176 may also include a radiopharmaceutical dispensing system 186, which facilitates extraction of the radiopharmaceutical into a vial or syringe 188. In certain embodiments, the various components and functions of the system 176 are disposed within a radiopharmacy, which prepares the syringe 188 of the radiopharmaceutical for use in a nuclear medicine application. For example, the syringe 188 may be prepared and delivered to a medical facility for use in diagnosis or treatment of a patient.

[0065] FiG. 19 is a block diagram of an exemplary nuclear medicine imaging system 190 utilizing the syringe 188 of radiopharmaceutical provided using the system 176 of FIG. 18. As illustrated, the nuclear medicine imagining system 190 includes a radiation detector 192 having a scintillator 194 and a photo detector 196. In response to radiation 198 emitted from a tagged organ within a patient 200, the scintillator 194 emits light that is sensed and converted to electronic signals by the photo detector 196. Although not illustrated, the imaging system 190 also can include a collimator to coilimate the radiation 198 directed toward the radiation detector 192. The illustrated imaging system 190 also includes detector acquisition circuitry 202 and image processing circuitry 204. The detector acquisition circuitry 202 generally controls the acquisition of electronic signals from the radiation detector 192. The image processing circuitry 204 may be employed to process the electronic signals, execute examination protocols, and so forth. The illustrated imaging system 190 also includes a user interface 206 to facilitate user interaction with the image processing circuitry 204 and other components of the imaging system 190. As a result, the imaging system 190 produces an image 208 of the tagged organ within the patient 200. Again, the foregoing procedures and resulting image 208 directly benefit from the radiopharmaceutical produced by the elution system 10 having one or more of the valves described above.

[0066] While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.

Claims

1. A generator for separating radioisotopes, the generator comprising: a radioisotope generator having an aperture; a resilient member connected to the radioisotope generator; and a sealing member connected to the radioisotope generator via the resilient member, wherein the sealing member is configured to obstruct the aperture depending on whether the resilient member is biased.

2. The generator of claim 1 , wherein the aperture is an aperture in a needle.

3. The generator of either claim 1 or 2, wherein the resilient member comprises a spring.

4. The generator of any of claims 1 -3, wherein the sealing member comprises an elastomer.

5. The generator of any of claims 1-4, wherein the resilient member is configured to bias the sealing member against a needle having the aperture in response to the removal of a container.

6. The generator of any of claims 1-5, wherein the sealing member is disposed about a needle.

7. The generator of any of claims 1 -5, wherein the sealing member is disposed adjacent a flared portion of a needle.

8. The generator of any of claims 1 -7, wherein the sealing member has a single degree of freedom relative to the radioisotope generator,

9. The generator of any of claims 1-8, wherein the sealing member is configured to seal the aperture in response to the removal of an eluate receptacle and unseal the aperture in response to the approach of the eluate receptacle.

10. The generator of any of claims 1-9, comprising: a body through which the sealing member is configured to translate and in which the resilient member is disposed; a sealing-member support connected to the sealing member and slideably connected to the body; and a needle, wherein the aperture is disposed on a side of the needle, and wherein the needle is disposed in an passage through the sealing member.

11. The generator of any of claims 1-9, comprising: a plunger having a leg; a body having a leg aperture in which the leg is disposed, wherein the leg is configured to slide in the leg aperture and the leg aperture is configured to seal against the leg; a needle extending from inside the body to outside the body, wherein the aperture is through the needle and in the body; a generally static seal adjacent the aperture; and a dynamic seal adjacent the static seal and spaced away from the plunger by the leg, wherein the resilient member is configured to bias the dynamic seal against either the static seal or the leg, depending on whether the plunger is pressed toward the body.

12. The generator of any of claims 1-9, comprising: an upper body affixed to the sealing member; a lower body having a guide configured to guide movement of the upper body, wherein the resilient member is disposed between the upper body and the lower body; and a needle extending from the lower body through a hole in the sealing member, wherein the needle has the aperture.

13. A method for generating a radioisotope, the method comprising automatically closing a fluid port of a radioisotope generator in response to removal of a vial.

14. The method of claim 13, wherein the fluid port is a needle aperture.

15. The method of either claim 13 or 14, wherein the needle aperture is disposed on a side of a needle.

16. The method of any of claims 13-15, comprising automatically opening the fluid port of the radioisotope generator in response to the vial being connected to the radioisotope generator.

17. The method of any of claims 13-16, comprising biasing a resilient memberwith the vial.

18. The method of any of claims 13-17, wherein the resilient member comprises a helical, compression spring.

19. The method of any of claims 13-18, comprising sliding a sealing member along a needle.

20. The method of any of claims 13-18, comprising biasing a dynamic seal against a static seal connected to a needle.

21. A radioisotope-elution system, comprising: a generator; radiation shielding disposed at least partially about the generator; a fluid port fluidly coupled to the generator; and a valve configured to obstruct the outlet based on whether a container is connected to the generator.

22. The radioisotope-elution system of claim 21 , wherein the valve comprises a contact member configured to move a sealing member in response to a force from the container.

23. The radioisotope elution system of either claim 21 or 22, wherein the fluid port comprises a needle connected to the valve.

24. The radioisotope elution system of any of claims 21 -23, wherein the valve comprises a rubber sealing member.

25. The radioisotope elution system of any of claims 21-24, wherein the valve is configured to seal a needle aperture.

26. A valve for an elution system, the valve comprising: a needle having an aperture; a sealing member; and a resilient member connected to the needle and the sealing member, wherein the resilient member is configured to obstruct the aperture with the sealing member depending on whether a container is connected to the needle.

27. The valve of claim 26, wherein the aperture is offset from a tip of the needle and is on a side of the needle.

28. The valve of claim 26 or 27, wherein the sealing member comprises a passage in which the needle is slideably disposed.

29. The valve of any of claims 26-28, comprising a plunger configured to bias the resilient member as the needle is inserted in a container.

30. The valve of any of claims 26-29, comprising an upper housing and a lower housing, wherein the upper housing is configured to slide into the lower housing, and wherein the resilient member is disposed between the upper housing and the lower housing.