The invention relates generally to radioisotope elution systems and, more specifically, to self-aligning components for use in such systems.
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.
Nuclear medicine uses radioactive material for diagnostic and therapeutic purposes by injecting a patient with a dose of the radioactive material, which concentrates in certain organs or biological regions of the patient. Radioactive materials typically used for nuclear medicine include Technetium-99m, Indium-111, and Thallium-201 among others. Some chemical forms of radioactive materials naturally concentrate in a particular tissue, for example, iodide (I-131) concentrates in the thyroid. Radioactive materials are often 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 in the field of nuclear medicine. At relatively low doses of the radiopharmaceutical, a radiation imaging system (e.g., a gamma camera) may be utilized to provide an image of the organ or biological region that collects the radiopharmaceutical. Irregularities in the image are often indicative of a pathology, such as cancer. Higher doses of the radiopharmaceutical may be used to deliver a therapeutic dose of radiation directly to the pathologic tissue, such as cancer cells.
A variety of systems are used to generate, enclose, transport, dispense, and administer radiopharmaceuticals. Using these systems often involves manual alignment of components, such as male and female connectors of containers. Unfortunately, the male connectors can be damaged due to misalignment with the corresponding female connectors. For example, hollow needles can be bent, crushed, or broken due to misalignment with female connectors. As a result, the systems operate less effectively or become completely useless. If the systems contain radiopharmaceuticals, then the damaged connectors can result in monetary losses or delays with respect to nuclear medicine procedures.
Certain exemplary aspects of the 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.
In some embodiments of the present invention, a radioisotope elution system includes self-aligning components that protect needles from being damaged. In one embodiment, a radioisotope generator includes an alignment structure that is keyed to a complementary alignment structure on a lid of an auxiliary radiation shield. The complementary alignment structure may be inserted into the alignment structure, and the position of the lid relative to the radioisotope generator may be generally fixed. Once these components are aligned, apertures in the lid may be used to guide various components onto the needles of the generator in a controlled manner, thereby reducing the likelihood of a misaligned component damaging the needles.
A first aspect of the present invention is directed to a radioisotope elution system that includes a radioisotope generator having an alignment structure configured to interface with a complementary alignment structure on a radiation shield.
A second aspect of the invention is directed to a radiation shield for shielding a radioisotope generator. The radiation shield has a shield lid that includes an alignment structure configured to align the shield lid to a radioisotope generator.
A third aspect of the invention is directed to radioisotope elution system that includes an auxiliary shield having a top plane, a shield lid that includes a handle, and a radioisotope generator disposed in the auxiliary shield and biased by the weight of the shield lid. The shield lid may be disposed in the auxiliary shield, and the handle may cross the top plane.
A fourth aspect of the invention is directed to a method of operating a radioisotope elution system. The method includes aligning a radiation shield lid to a radioisotope generator via a first alignment structure on the radiation shield lid and a second alignment structure on the radioisotope generator.
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.
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:
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.
When introducing elements of various embodiments of the present invention, the articles “a”, “an”, “the”, and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including”, and “having” are intended to be 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 is made for convenience, but does not require any particular orientation of the components. As used herein, the term “coupled” refers to the condition of being directly or indirectly connected or in contact.
The illustrated auxiliary shield assembly 12 includes an auxiliary shield lid 18 and an auxiliary shield 20. For brevity, the auxiliary shield lid 18 is referred to as a “lid.” The auxiliary shield 20 may include a top ring 22, a base 24, and a plurality of step-shaped or generally tiered modular rings 26, which are disposed one over the other between the base 24 and the top ring 22 (see
The illustrated generator body 30 includes an elution column configured to generate and output a desired radioisotope. Except for the needle assembly 32, the various components of the elution column of the radioisotope generator 28 are not shown in detail. However, elution columns are well known to those of ordinary skill in the art (see U.S. Pat. No. 5,109,160 and US Patent Application Publication No. 2005/0253085, for example). As such, one of ordinary skill in the art could easily employ various aspects of the invention with radioisotope generators having a wide range of elution column designs.
Certain medically useful radioisotopes have relatively short half-lives (e.g., technetium-99m (Tc99m) has a half-life of approximately 6 hours). To potentially expand the useful life of the radioisotope generator 28, the elution column may include a more stable radioisotope that decays into the desired radioisotope (e.g., molybdenum-99 (Mo99) has a half-life of approximately 66 hours and decays into Tc99m). As the desired radioisotope is needed, it may be separated from the more stable radioisotope with an elution process, as explained below. The generator body 30 may also include shielding configured to diminish radiation, and tubing to conduct fluids into and out of the elution column.
Externally, the illustrated generator body 30 includes a lifting strap 36, two strap supports 38, 40, and outer rings 42, 44. The two strap supports 38, 40 extend upward from the generator body 30 and pivotably interconnect (e.g., connect in a manner that enables pivoting or pivot-like motion (e.g., flexing, elastic deformation, etc.)) to opposing ends of the lifting strap 36. The outer rings 42, 44 are near the top and bottom of the generator body 30, respectively. As depicted in
The needle assembly 32 may include an input needle 46, an output needle 48, and a vent needle 50. The tubing in the generator body 30 may fluidly interconnect (e.g., connect either directly or indirectly in a manner that enables fluid to flow there between) to needles 46, 48, and/or 50. Specifically, the input needle 46 may fluidly interconnect with an input to the elution column, and the output needle 48 may fluidly interconnect with an output from the elution column. The vent needle 40 may vent to atmosphere to equalize pressure during an elution, as explained below. The needles 46, 48, 50 are hollow to facilitate fluid flow therein.
The cap 34 may include needle apertures 52, 54, support channels 56, 58, tabs 60, 62, 64, 66, a top surface 67, and an alignment structure 68. Here, the term “alignment structure” refers to a member or surface that reduces the range of relative motion between two components as those components are interconnected, coupled, or brought into proximity. In other words, an alignment structure reduces the number of degrees of freedom between components as the components are interfaced (e.g., brought into contact with each other or an intermediary component such that mechanical forces may be transmitted from one alignment structure to another). The needle apertures 52, 54 are disposed within the alignment structure 68. In other embodiments, the needle apertures 52, 54 may be positioned elsewhere relative to the alignment structure 68, e.g., not within it or on a separate component. The support channels 56, 58 are shaped to complement the strap supports 38, 40 and orient the cap 34 relative to the generator body 30. That is, the support channels 56, 58 cooperate with the strap supports 38, 40 to align the cap 34 to the generator body 30 in one of a finite number of discrete orientations and positions, such as a single orientation and position.
The illustrated alignment structure 68 generally defines a cylinder with an oval base 70 and walls 72 that are generally perpendicular to the base 70. As used herein, the term “cylinder” refers to a surface or solid bounded by two parallel planes and generated by a straight line (i.e., a generatrix) moving parallel to the given planes and tracing a curve (including but not limited to a circle) bounded by the planes and lying in a plane perpendicular or oblique to be given planes. The base 70 is generally parallel to the base 24 of the auxiliary shield 20, and the cylinder defined by the alignment structure 68 has a single plane of symmetry that is generally perpendicular to the base 70. The illustrated alignment structure 68 is recessed in word into the cap 34 and maybe generally characterized as a female alignment structure. In other embodiments, the alignment structure 68 may have a variety of different shapes and configurations. For example, the alignment structure 68 may be generally asymmetric, or the alignment structure 68 may extend outward from the cap 34. As described below, the alignment structure 68 may align the lid 18 to the radioisotope generator 28.
With reference to
The elution tool aperture 84 and eluant aperture 86 extend through the illustrated lid 18. These apertures 84, 86 may have a generally circular horizontal cross-section that is generally constant through at least a portion of the vertical thickness of the lid 18. The apertures 84, 86 may be disposed within and extend through the complementary alignment structure 76. In other embodiments, these features 84, 86, 76 may be disposed else elsewhere with respect to one another. The eluant aperture 86 may include a flared portion 90 (see
Referring general to
The eluant assembly 16 may include an eluant shield 98 and an eluant source 100. The illustrated eluant shield 98 has a handle 102, guide members 104, 106, and a recessed portion 108. The eluant shield 98 may be made of radiation shielding material, such as those materials discussed above. The guide members 104, 106 are shaped to fit within the flared portion 90 of the lid 18 and guide the eluant shield 98 into a resting position on the lid 18 (see
A variety of components may interface with the lid 18. As discussed above, the eluant source 100 may slide through the eluant aperture 86 in the lid 18, and contact between these components 86, 100 may tend to reduce horizontal translation of the eluant source 100 and rotation of the eluant source 100 about horizontal axes. Similarly, the elution tool 14 may slide through the elution tool aperture 84, and contact between these components 14, 84 may tend to reduce horizontal translation of the elution tool 14 and rotation of the elution tool 14 about horizontal axes. In other words, the lid 18 may tend to constrain movement of the elution tool 14 and eluant source 100 to an up-and-down motion that is parallel (e.g., coaxial) with the needles 46, 48, 50 as these components 14, 100 are brought in contact with the needles 46, 48, 50. Aligning the elution tool 14 and eluant source 100 with the needles 46, 48, 50 before they make contact may reduce the chances of the needles 46, 48, 50 being damaged. The eluant shield 98 may rest on the lid 18 and cover a portion of the eluant source 100 that extends above a top of the lid 18.
In the assembled state depicted by
In operation, an eluant inside the eluant source 100 is circulated through the inlet needle 46, through the radioisotope generator 28 (including the elution column), and out through the outlet needle 48 into the eluate receptacle 94. This circulation of the eluant washes out or generally extracts a radioactive material, e.g., a radioisotope, from the radioisotope generator 28 into the eluate receptacle 94. For example, one embodiment of the radioisotope generator 28 includes an internal radiation shield (e.g., lead shell) that encloses a radioactive parent, such as molybdenum-99, affixed to the surface of beads of alumina or a resin exchange column. Inside the radioisotope generator 28, the parent molybdenum-99 transforms, 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 radioisotope generator 28. Accordingly, the daughter radioisotope, e.g., technetium-99m, can be extracted or washed out 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, e.g., technetium-99m, within the eluate receptacle 94, the elution tool 14 can be removed from the radioisotope elution system 10. As discussed in further detail below, the extracted daughter radioisotope can then, if desired, be combined with a tagging agent to facilitate diagnosis or treatment of a patient (e.g., in a nuclear medicine facility).
The illustrated radioisotope elution system 10 is a dry elution system. Prior to an elution, the eluant receptacle 94 is substantially evacuated, and the eluant source 100 is filled with a volume of saline that generally corresponds to the desired volume of radioisotope solution. During an elution, the vacuum in the eluant receptacle 94 draws saline from the eluant source 100, through the radioisotope generator 28, and into the eluant receptacle 94. After substantially all of the saline has been drawn from the eluant source 100, a remaining vacuum in the eluant receptacle 94 draws air through the radioisotope generator 28, thereby removing fluid that might otherwise remain in the radioisotope generator 28. Air or other appropriate fluids may flow into the eluant source 100 through the vent needle 50 and into the radioisotope generator 28 through the input needle 46. The volume and pressure of the eluant receptacle 94 may be selected such that substantially all of the eluant fluid is drawn out of the radioisotope generator 28 by the end of an elution operation.
In view of the operation of the elution system 10, proper alignment of the various components may be particularly important to the life of the needles 46, 48, 50 and, thus, proper circulation of the eluant from the eluant source 100 through the radioisotope generator 28 and into the eluant receptacle 94. For example, when the eluant source 100 is coupled to the needles 46, 50, it may bend the needles 46, 50 if not properly aligned. Similarly, pressing the elution tool 14 down onto the needle 48 may bend the needle 48 if the elution tool 14 is not properly aligned. Certain embodiments of a subsequently described elution process may align the eluant source 100 with the needles 46, 50 before the eluant source 100 contacts the needles 46, 50 and, also, may align the elution tool 14 with the needle 48 before the elution tool 14 contacts the needle 48. Moreover, certain embodiments may guide the elution tool 14 and the eluant source 100 through an up or down movement that is parallel with the needles 46, 48, 50 when the elution tool 14 and eluant source 100 are positioned over the needles 46, 48, 50 and properly oriented.
An elution process 112 will now be described with reference to
After aligning the radiation shield to the generator, a source of eluant may be aligned to the radiation shield, as depicted by block 116. For example, the eluant source 100 may be aligned to the lid 18. Aligning the eluant source 100 may include vertically orienting eluant source 100 over the eluant aperture 86 and inserting the eluant source 100 through the eluant aperture 86 until the needles 46, 50 have substantially penetrated the eluant source 100. Because the lid 18 is aligned (or referenced) to the radioisotope generator 28 and the eluant source 100 is aligned (or referenced) to the lid 18, the eluant source 100 may be aligned (or referenced) to the radioisotope generator 28. Moreover, the path traveled by the eluant source 100 as it interfaces or makes contact with the needles 46, 50 may be controlled by the eluant aperture 86. That is, the eluant aperture 86 may guide the eluant source 100 onto the needles 46, 50 in a path that is substantially parallel to the needles 46, 50.
Next an elution tool is aligned to the radiation shield, as depicted by block 118. In the embodiment of
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 cap all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
This application is a continuation of U.S. application Ser. No. 12/441,919 filed Mar. 19, 2009, which is a National Stage Entry of PCT/US2007/021344 filed Oct. 3, 2007, which claims priority from U.S. Provisional Application No. 60/849,869, filed Oct. 6, 2006, all of which are incorporated herein by reference.