Coaxial needle technetium elution generator

Abstract

The elution generator has an elution column having a vessel and a septum defining an interior volume, and a radiation shield. The radiation shield includes an upper shield portion and a lower shield portion, the upper shield portion defining a central recess and a coaxial flow needle extending downwardly into the central recess, and the lower shield portion having a body portion defining the central recess. The elution column is disposed within the central recess of the lower shield portion, the body portion of the lower shield portion is disposed within the central recess of the upper shield portion, and the coaxial flow needle extends downwardly through the septum into the interior volume of the elution column.

Description

[Technical Field]

[0001] The invention disclosed herein relates generally to a system for producing radioisotope targets in a nuclear reactor, and more specifically to a system for eluting technetium-99m from irradiated radioisotope targets. [Background technology]

[0002] Technetium-99m (Tc-99m) is the most commonly used radioisotope in nuclear medicine (e.g., medical imaging). Tc-99m (m is metastable) is typically used in patients and in conjunction with certain equipment to image the patient's internal organs. However, the half-life of Tc-99m is only 6 hours. Thus, readily available Tc-99m sources are of particular interest and / or need, at least in the field of nuclear medicine.

[0003] Given the short half-life of Tc-99m, Tc-99m is typically obtained where and / or when needed (e.g., pharmacies, hospitals, etc.) via Mo-99 / Tc-99m generators. Mo-99 / Tc-99m generators are devices used to extract or elute metastable isotopes of technetium (i.e., Tc-99m) from decaying molybdenum-99 (Mo-99) sources by passing saline through the Mo-99 material. Mo-99 is unstable and decays to Tc-99m with a half-life of 66 hours. Mo-99 is typically produced in high-flux nuclear reactors by irradiating highly enriched uranium targets (93% uranium-235). It undergoes subsequent processing steps to reduce the Mo-99 to a usable form (e.g., titanium-99 molybdate (Ti-Mo99)) before being transported to the Mo-99 / Tc-99m generator manufacturing site. Mo-99 / Tc-99m generators are then distributed from these centralized locations to hospitals and pharmacies throughout the country. Due to the short half-life of Mo-99 and the limited number of existing production sites, it is desirable to both minimize the amount of time required to reduce irradiated Mo-99 material to a usable form and to increase the number of sites where the irradiation process can occur. Summary of the Invention [Problem to be solved by the invention]

[0004] As shown in FIG. 14, existing elution generators typically include an elution column 10 having an inlet 12 connected to one end of the column and an outlet 14 connected to the other end of the column, meaning that the elution column has only one-way flow. Thus, known elution columns necessarily have a material to be eluted 16 and a filter medium 18 arranged in a line within the column, resulting in a long, narrow elution column. Elution columns require appropriate shielding 20 to protect medical radiation workers from exposure during handling the generator and the elution process. Thus, the shielding of known elution columns tends to be bulky and heavy, leading to increased shipping and handling costs.

[0005] Therefore, there is at least a need for a system and process for the timely production of titanium-99 molybdate material suitable for use in Tc-99m generators. [Means for solving the problem]

[0006] One embodiment of the present disclosure provides an elution generator having an elution column and a radiation shield. The elution column has a container defining an interior volume and a septum sealing an opening to the interior volume, and the radiation shield includes an upper shield portion and a lower shield portion. The upper shield portion defines a central recess and a coaxial flow needle assembly extending downwardly into the central recess. The lower shield portion has a base and a body portion extending upwardly from the base, the body portion defining the central recess configured to receive the elution column therein. The elution column is disposed within the central recess of the lower shield portion, the body portion of the lower shield portion is disposed within the central recess of the upper shield portion, and the coaxial flow needle extends downwardly through the septum into the interior volume of the elution column.

[0007] Another embodiment of an elution generator includes an elution column and a coaxial flow needle assembly, the elution column having a container defining an interior volume, a septum sealing an opening to the interior volume, a bottom filter medium disposed adjacent to the bottom of the container, and an upper filter medium disposed adjacent to the top of the container. The coaxial flow needle assembly includes a coaxial flow needle having an inner needle and an outer needle, the outer needle being coaxially disposed around the inner needle. A lowermost portion of the inner needle extends downwardly into the bottom filter medium, and a lowermost portion of the outer needle extends downwardly into the upper filter medium.

[0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0009] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1 is a diagram of a coaxial needle technetium elution generator according to one embodiment of the present invention positioned within a package. [Figure 1B] FIG. 1 is a diagram of a coaxial needle technetium elution generator according to one embodiment of the present invention positioned within a package. [Figure 1C] FIG. 1 is a diagram of a coaxial needle technetium elution generator according to one embodiment of the present invention positioned within a package. [Figure 2A] FIG. 1B is a perspective view of the elution generator shown in FIG. 1A. [Figure 2B] FIG. 1C is a perspective view of the elution generator shown in FIG. 1B. [Figure 2C] FIG. 1D is a cross-sectional view of the elution generator shown in FIG. 1C. [Figure 3] FIG. 2D is a side view of the coaxial needle assembly of the elution generator shown in FIG. 2C. [Figure 4] FIG. 2D is an exploded cross-sectional view of the elution generator shown in FIG. 2C. [Figure 5A] FIG. 2D is a cross-sectional view of the elution generator shown in FIGS. 2A-2C. [Figure 5B] FIG. 2D is a cross-sectional view of the elution generator shown in FIGS. 2A-2C. [Figure 6A] FIG. 2D is a side view of the upper shield half of the elution generator shown in FIGS. 2A-2C. [Figure 6B] FIG. 2D is a side view of the upper shield half of the elution generator shown in FIGS. 2A-2C. [Figure 7A]FIG. 2D is a perspective view of the upper and lower shields of the elution generator shown in FIGS. 2A-2C. [Figure 7B] FIG. 2D is a perspective view of the upper and lower shields of the elution generator shown in FIGS. 2A-2C. [Figure 7C] FIG. 2D is a perspective view of the upper and lower shields of the elution generator shown in FIGS. 2A-2C. [Figure 8] FIG. 2D is a bottom perspective view of the upper shield of the elution generator shown in FIGS. 2A-2C. [Figure 9] FIG. 2D is a perspective view of the elution column of the elution generator shown in FIGS. 2A-2C, including an inlet filter and an outlet filter. [Figure 10] FIG. 2D is a side view of the inlet and outlet of the coaxial needle of the elution generator shown in FIGS. 2A-2C, including a luer lock. [Figure 11A] FIG. 2C is a perspective view of the elution generator shown in FIGS. 2A-2C undergoing an elution process. [Figure 11B] FIG. 2C is a perspective view of the elution generator shown in FIGS. 2A-2C undergoing an elution process. [Figure 12] FIG. 2D is a partial cross-sectional view of the elution generator shown in FIGS. 2A-2C, including a shielded outlet. [Figure 13A] FIG. 1 is a cross-sectional view of an elution column according to another embodiment of the present invention. [Figure 13B] FIG. 1 is a cross-sectional view of an elution column according to another embodiment of the present invention. [Figure 14] FIG. 1 is a cross-sectional view of a prior art elution column. DETAILED DESCRIPTION OF THE INVENTION

[0011] Repeat use of reference numerals in the present specification and drawings is intended to represent same or similar structures or elements of the invention according to the present disclosure.

[0012] Reference will now be made in detail to the presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation, and not as a limitation of the invention. Indeed, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. For example, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents.

[0013] As used herein, terms referring to a direction or position relative to the orientation of the coaxial needle technetium elution generator, including, but not limited to, "vertical," "horizontal," "top," "bottom," "above," or "below," refer to a direction and relative position relative to the orientation of the elution generator in normal intended operation, as shown in Figures 1B, 5A, and 5B. Thus, for example, the terms "vertical" and "top" refer to a vertical orientation and relative top position in the perspective views of Figures 1B, 5A, and 5B, and should be understood in that context even with respect to an elution generator that may be positioned in a different orientation.

[0014] Furthermore, the term "or," as used in this application and the appended claims, is intended to mean an inclusive "or," rather than an exclusive "or." That is, unless otherwise specified or clear from the context, the phrase "X uses A or B" is intended to mean any of the natural inclusive permutations. That is, the phrase "X uses A or B" is satisfied by any of the following: X uses A, X uses B, or X uses both A and B. Also, the articles "a" and "an," as used in this application and the appended claims, should be generally construed to mean "one or more," unless otherwise specified or clear from the context to refer to the singular form. Throughout this specification and the claims, the following terms have at least the meanings expressly associated herein, unless the context dictates otherwise. The meanings specified below do not necessarily limit the terms, but merely provide illustrative examples of the terms. The meaning of "a," "an," and "the" may include plural reference, and the meaning of "in" may include "in" and "on." The phrase "in one embodiment" as used herein does not necessarily refer to the same embodiment, although it may.

[0015] 1A-1C, an elution generator 100 according to the present disclosure is shown in its corresponding packaging for shipping. As shown, the elution generator 100 is disposed within a polyurethane foam inner packaging 102 and housed within a double-walled heavy-duty cardboard box 104 exterior. Preferably, the cardboard box is 275 lbs. (125kg) Burst strength of at least 51 pounds per square inch (351kPa, 35.9t / m 2 )Edge Crush Test (ECT) standards. As shown, the elution generator 100 is preferably nested within a foam bottom 102a and a foam top 102b. In addition to the recess 106 configured to receive the elution generator 100, additional recesses (not shown) can be provided to receive vials and other consumables to be shipped with the elution generator.

[0016] 2A-2C, one exemplary embodiment of an elution generator 100 includes a radiation shield assembly 107 including an upper shield portion 108 and a lower shield portion 110 configured to be slidably received within a recess 112 formed in the upper shield portion 108. Preferably, both the upper shield portion 108 and the lower shield portion 110 are formed from depleted uranium to provide adequate shielding for the operator from eluted materials. In alternative embodiments, tungsten or other high-density materials may be utilized for the shield portions.

[0017] 6A and 6B, the upper shield portion 108 is formed from a first half 108a and a second half 108b and is configured to receive a coaxial flow needle assembly 120 (FIG. 3) therein, the coaxial flow needle assembly 120 including a coaxial flow needle formed by an inner needle 122 and an outer needle 124, and first and second ports 123 and 125, respectively. As shown, the upper shield portion 108 includes a first flow channel 114 and a second flow channel 116, which are positioned radially outwardly of or offset from a centrally located needle recess 118 configured to receive the coaxial flow needle formed therein by both the outer needle 122 and the center needle 124. In this manner, there is no direct path through the upper shield portion 108 formed by either path from the elution generator to the external environment that can transmit radiation in a straight line without encountering a portion of the radiation shield 107. As shown, the upper shield portion 108 includes an integral handle 109 formed from 7075-T6 aluminum to aid in handling the elution generator 100. Alternatively, rather than a rigid handle, a strap handle of a flexible material can be utilized.

[0018] 7A and 7B, lower shield portion 110 includes a base 111 and a cylindrical sidewall 113 extending upwardly therefrom, preferably forming a cylindrical recess 118 therein for receiving elution column 130. Note that the horizontal cross-sectional shape of recess 118 will depend on the horizontal cross-sectional shape of the elution column to be housed therein. As best seen in FIG. 2C, elution column 130 is positioned within recess 118 of lower shield portion 110 before cylindrical wall 113 of lower shield portion 110 is slidably received within recess 112 of upper shield portion 108, as described in more detail below. In the illustrated embodiment, elution column 130 includes a glass or polycarbonate vial and a crimp cap 132 with a septum. Prior to shipping, the upper and lower shield portions 108, 110 are assembled within an outer plastic shield 126 formed from materials such as, but not limited to, Delrin, polyethylene, polyoxymethylene, and polyethylene terephthalate glycol plastics, and then placed within the polyurethane foam packaging 102.

[0019] Referring now to FIG. 3 , an exemplary coaxial flow needle assembly 120 according to the present disclosure is shown. As previously described, the coaxial needle 120 includes a first port 123 and a second port 125, with the first port 123 in fluid communication with the outer needle 122 and the second port 125 in fluid communication with the inner needle 124. Note that either port can be used as an inlet or an outlet, depending on whether saline inflow is provided through the outer needle 122, as shown in FIG. 5A , or through the inner needle 124, as shown in FIG. 5B . As previously described and best seen in FIGS. 6A and 6B , the coaxial needle assembly 120 is received within corresponding recesses 114, 116, and 118 formed in the two halves of the outer shield portion 108, with the outer needle 122 and inner needle 124 extending downwardly into the recess 112 in which the cylindrical sidewall 113 of the lower shield portion 110 is slidably received. 5A and 5B, an alumina filter medium 136 is provided at the bottom of the vial of the elution column 130 such that the lowermost portion 124a of the inner needle 124 extends downwardly into the bottom filter medium 136. Additionally, an alumina filter medium 138 is provided at the lowermost portion 122a of the outer needle 122 so that the lower filter medium 136 and upper filter medium 138 can capture powdered material being eluted before the eluate exits the elution column 130 via the outer needle 122 or inner needle 124 through either the first port 123 or the second port 125.

[0020] 9, additional filters 140 can be provided at the first port 123 and the second port 125 of the coaxial needle 122 to further capture particulates that may be present in the eluate. Preferably, 1-2 μm filters are provided at the first port 123 and the second port 125 to capture particulates, although other size filters may be used. Also, as shown in FIG. 10, needleless connectors 142, such as those manufactured by BD MaxZero, can be used at the first port 123 and the second port 125 of the coaxial needle assembly 120 to help maintain port sterility and reduce the chance of a worker getting a needlestick injury.

[0021] Referring now to FIG. 4, assembly of the elution generator 100 can be preferably performed by a robot to reduce the potential for radiation exposure to personnel. First, with the lower shield portion 110 positioned within the outer plastic shield 126, the elution column 130 is lifted by the robot and placed into the recess 115 of the lower shield portion 110. Preferably, an isopropyl wipe system is utilized to sterilize the septum of the elution column 130. Next, the robotic gripper retrieves the pre-assembled upper shield portion 108 with the sterilized coaxial needle assembly 120 attached. The upper shield portion 108 is lowered into the outer plastic shield 126 so that the cylindrical sidewall 113 of the lower shield portion 110 is slidably received within the recess 112 of the upper shield portion 108. As the upper shield portion 108 is lowered, the lowest portion 124a of the inner needle 124 pierces the septum of the elution column 130, passing the material to be eluted until the lowest portion 124a of the inner needle 124 is positioned within the bottom filter media 136 of the elution column, as shown in Figures 5A and 5B. The elution generator 100 is now ready to be placed within the foam packaging 102 and boxed for shipment to the destination where the elution procedure will be performed.

[0022] 11A and 11B, the elution process can be performed using a vial tube 160 containing saline and an additional vial tube 162 under vacuum, such as a vial tube used when drawing blood. First, the vial tube 160 containing saline is placed into a port on the coaxial needle assembly 120 (FIGS. 5A and 5B) that serves as the inlet, and then the evacuated vial tube 162 is placed into a port on the coaxial needle assembly 120 that serves as the outlet. The vacuum present in the outlet vial tube 162 draws the saline downward into the elution column 130 and then back out of the elution column 130. As previously mentioned, the outer needle 122 may be used for inflow and the inner needle 124 for outflow, as shown in FIG. 5A, or conversely, the inner needle 124 may be used for inflow and the outer needle 122 for outflow. 12, the port of the coaxial needle assembly 120 used to collect the eluate may be provided with an exit shield 170 to protect the operator from exposure to radiation. Similarly, the filter media 172 may be provided within a disposable needle access device 174 so that the filter media is easily replaceable.

[0023] 13A and 13B, an alternative embodiment of an elution column 180 according to the present disclosure is shown. Similar to the initially disclosed embodiment, the elution column 180 shown in FIGS. 13A and 13B utilizes a coaxial flow of saline during the elution process. Note, however, that while the flow within the elution column 180 is coaxial, the needle 182 employed is not. Rather, a large-diameter needle 182 is employed, within which the substance 184 to be eluted, i.e., Mo-99, is disposed. The large-diameter needle is received within a corresponding recess 186 formed in a filter media 190, extending the length of the large-diameter needle 182. As shown, porous flutes 186 are employed on both ends of the large-diameter needle 182 to further improve filtration of the eluate.

[0024] While one or more preferred embodiments of the present invention have been described above, it should be understood that those skilled in the art can make various modifications and variations to the present invention without departing from the scope and spirit of the invention. It is intended that the present invention encompass all such modifications and variations that come within the scope and spirit of the appended claims and their equivalents.

Claims

1. An elution generator having an elution column and a radiation shield, the elution column includes a container defining an interior volume and a septum sealing an opening to the interior volume; the radiation shield comprises an upper shield portion and a lower shield portion; the upper shield portion having a central recess and a coaxial flow needle assembly including a coaxial flow needle extending downwardly into the central recess; the lower shield portion having a base and a body extending upwardly from the base, the body defining a central recess configured to receive the elution column therein; the elution column is disposed within a central recess of the lower shield portion; a body portion of the lower shield portion disposed within a central recess of the upper shield portion; The coaxial flow needle extends downwardly through the septum into the interior volume of the elution column.

2. The coaxial flow needle further comprises an inner needle and an outer needle; The elution generator of claim 1 , wherein the outer needle is coaxially disposed around the inner needle.

3. the upper shield portion further comprises a central needle recess, a first flow channel, and a second flow channel; The elution generator of claim 2 , wherein both the first flow path and the second flow path are disposed radially outward from the central needle recess.

4. The elution generator of claim 3 , wherein the coaxial flow needle is disposed within the central needle recess.

5. the coaxial flow needle assembly further comprising a first port and a second port; the first port is disposed within the first flow passage of the upper shield portion; The elution generator of claim 4 , wherein the second port is disposed in the second flow path of the upper shield portion.

6. a distal end of the first port is disposed outside the radiation shield; a proximal end of the first port in fluid communication with the outer needle; a distal end of the second port is disposed outside the radiation shield; The elution generator of claim 5 , wherein a proximal end of the second port is in fluid communication with the inner needle.

7. The elution column comprises: a bottom filter medium disposed adjacent the bottom of the container; an upper filter medium disposed adjacent to an upper portion of the container; Furthermore, a lowermost portion of the inner needle extends downward into the bottom filter medium; The elution generator of claim 2 , wherein a lowermost portion of the outer needle extends downwardly into the upper filter medium.

8. 8. The elution generator of claim 7, further comprising an elutable powder disposed between the top filter medium and the bottom filter medium.

9. The elution generator of claim 1 , wherein the central recess of the upper shield portion and the central recess of the lower shield portion are cylindrical.

10. 1. An elution generator comprising an elution column and a coaxial flow needle assembly, The elution column a container defining an interior volume; a partition sealing an opening to the interior volume; a bottom filter medium disposed adjacent the bottom of the container; an upper filter medium disposed adjacent to an upper portion of the container; and the coaxial flow needle assembly includes a coaxial flow needle having an inner needle and an outer needle, the outer needle being coaxially disposed around the inner needle; a lowermost portion of the inner needle extends downward into the bottom filter medium; An elution generator, wherein a lowermost portion of the outer needle extends downwardly into the upper filter medium.

11. further comprising a radiation shield having an upper shield portion and a lower shield portion; the upper shield portion defines a central recess, and the coaxial flow needle of the coaxial flow needle assembly extends downwardly into the central recess; the lower shield portion having a base and a body extending upwardly from the base, the body defining a central recess configured to receive the elution column therein; the elution column is disposed within a central recess of the lower shield portion; 11. The elution generator of claim 10, wherein the body portion of the lower shield portion is positioned within the central recess of the upper shield portion such that the coaxial flow needle extends downwardly through the septum into the interior volume of the elution column.

12. the upper shield portion further comprises a central needle recess, a first flow channel, and a second flow channel; The elution generator of claim 11 , wherein both the first flow path and the second flow path are disposed radially outward from the central needle recess.

13. The elution generator of claim 12 , wherein the coaxial flow needle is disposed within the central needle recess.

14. the coaxial flow needle assembly further comprising a first port and a second port; the first port is disposed within the first flow passage of the upper shield portion; The elution generator of claim 13 , wherein the second port is disposed in the second flow path of the upper shield portion.

15. a distal end of the first port is disposed outside the radiation shield; a proximal end of the first port in fluid communication with the outer needle; a distal end of the second port is disposed outside the radiation shield; The elution generator of claim 14 , wherein a proximal end of the second port is in fluid communication with the inner needle.

16. 11. The elution generator of claim 10, further comprising an elutable powder disposed between the top filter medium and the bottom filter medium.

17. The elution generator of claim 11 , wherein the central recess of the upper shield portion and the central recess of the lower shield portion are cylindrical.

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