Patent Publication Number: US-2018028836-A1

Title: Radioactive medical device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 62/367,805 filed on Jul. 28, 2016, the disclosure of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure pertains to medical devices, and methods for manufacturing medical devices. More particularly, the present disclosure pertains to radioactive elements connected with other structures, and methods for manufacturing and using such devices. 
     BACKGROUND 
     Some cancers and neoplasms are easier to treat with radiation than others. Hard-to-reach neoplasms, such as those in the esophagus, intestines and other lumens, are often treated via Brachytherapy so as to minimize radiation to adjacent, healthy tissue. 
     Brachytherapy delivers radiation to small tissue volumes while limiting exposure of healthy tissue. In this regard, the delivered radiation conforms more to the target than any other form of radiation, (including proton therapy) as less normal transient tissue is treated. It features placement of radiation sources, such as small radioactive particles or needles, near or within the target tissue, thus having the advantage over External Beam Radiation Therapy (EBRT) of being more focalized and less damaging to surrounding healthy tissue. 
     Brachytherapy is a common treatment for esophageal, prostate, and other cancers. Brachytherapy has been used to treat prostate cancer which has been practiced for more than half a century. In this situation, very low activity material emitting a low energy is placed next to or within a tumor. Traditionally, these low emitting devices have mostly been left in place permanently except in extraordinary circumstances. It would be desirable to utilize radioactive material in conjunction with interventional medical devices when clinically appropriate, and/or it may be desirable to tailor the delivery of radioactive energy or radioactive sources according to clinical needs. For example, it may be advantageous to couple a radiation source with a frame when clinically necessary and/or it may be advantageous to adjust the position and the activity of the radioactive source on a frame in response to changes in tumor shape and size, carrier position, and other relevant therapeutic factors. 
     BRIEF SUMMARY 
     This disclosure provides design, material, manufacturing method, and use alternatives for medical devices. An example medical device comprises a radioactive element positionable within a body lumen, the body lumen having an inner surface. The medical device also includes a frame attached to the radioactive element. The frame is also configured to position the radioactive element radially inward and away from the inner surface of the body lumen. 
     Alternatively or additionally to any of the embodiments above, the frame is configured to position the radioactive element in a central region of the body lumen. 
     Alternatively or additionally to any of the embodiments above, the device further includes a plurality of radioactive elements, wherein the plurality of radioactive elements are attached together to form an elongated radioactive strand. 
     Alternatively or additionally to any of the embodiments above, the radioactive element is removably attached to the frame. 
     Alternatively or additionally to any of the embodiments above, the frame includes one or more support arms extending radially away from the radioactive element. 
     Alternatively or additionally to any of the embodiments above, the one or more support arms each include a fixation member positioned on an end thereof. 
     Alternatively or additionally to any of the embodiments above, each of the one or more support arms further comprises a spring member attached thereto. 
     Alternatively or additionally to any of the embodiments above, each of the one or more support arms are configured to be releasably engaged to the body lumen. 
     Alternatively or additionally to any of the embodiments above, the frame includes a retrieval member, and wherein pulling the retrieval member collapses each of the one or more support arms toward the radioactive element. 
     Alternatively or additionally to any of the embodiments above, the device further includes an anchoring member positioned around the radioactive element, and wherein each of the one or more support arms include a first end secured to the anchoring member. 
     Alternatively or additionally to any of the embodiments above, the second ends of the one or more support arms are axially aligned. 
     Alternatively or additionally to any of the embodiments above, each of the one or more support arms are configured to permit the radioactive element to shift from a first position to a second position. 
     Alternatively or additionally to any of the embodiments above, shifting the support arms from a first position to a second position shifts the radioactive element in a radial direction, an axial direction, or both radial and axial directions. 
     Another example medical device comprises a support structure including a base member and one or more support members extending therefrom. The base member is configured to receive one or more radioactive elements. The base member is also configured to position the one or more radioactive elements in a central region of a body lumen. 
     Alternatively or additionally to any of the embodiments above, the one or more radioactive elements are configured to be removed from the support structure. 
     Alternatively or additionally to any of the embodiments above, each of the one or more support members are configured to be releasably engaged to the body lumen. 
     Alternatively or additionally to any of the embodiments above, the device further includes an anchoring member positioned around the support structure, and wherein each of the one or more support members include a first end secured to the base member and a second end secured to the anchoring member. 
     Alternatively or additionally to any of the embodiments above, each of the one or more support members are configured to permit the base member to shift from a first position to a second position. 
     Alternatively or additionally to any of the embodiments above, shifting the one or more support members from a first position to a second position shifts the base member in both a radial direction, an axial direction, or both radial and axial directions. 
     Another medical device comprises a radioactive element and an expandable scaffold including a base member and one or more support members extending radially from the base member. Each of the one or more support members has a first end attached to the scaffold and a second end attached to the base member. Further, the base member is configured to receive the radioactive element and the one or more support members is/are configured to suspend the base member in a central region of a body lumen. 
     The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The Figures, and Detailed Description, which follow, more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The disclosure may be more completely understood in consideration of the following detailed description in connection with the accompanying drawings, in which: 
         FIG. 1  is an example radioactive element and frame. 
         FIG. 2  is an example radioactive element. 
         FIG. 3  is an example radioactive strand having radioactive seeds and spacers. 
         FIG. 4  is a cross section of a radioactive element and frame taken along line  4 - 4  of  FIG. 1 . 
         FIG. 5  is a cross section of another example radioactive element and frame. 
         FIG. 6  is another example radioactive element and frame. 
         FIG. 7  is another example radioactive element and frame. 
         FIG. 8  is another example radioactive element and frame. 
         FIG. 9  is another example radioactive element and frame. 
         FIG. 10  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 11  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 12  is a cross section of the radioactive element and frame taken along line  12 - 12  of  FIG. 11 . 
         FIG. 13  is an alternative cross section of an example radioactive element and frame taken along line  12 - 12  of  FIG. 11 . 
         FIG. 14  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 15  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 16  is a cross section of the radioactive element and frame taken along line  16 - 16  of  FIG. 15 . 
         FIG. 17  is an alternative cross section of a radioactive element and frame taken along line  16 - 16  of  FIG. 15 . 
         FIG. 18  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 19  is a cross section of the radioactive element and frame taken along line  19 - 19  of  FIG. 18 . 
         FIG. 20  is a cross-section of an example medical device delivery system. 
         FIG. 21  is a cross section of the radioactive element and frame taken along line X-X of  FIG. 18 . 
         FIG. 22  is a cross section of another example radioactive element and frame. 
         FIG. 23  is a cross section of another example radioactive element and frame. 
         FIG. 24  is a cross section of another example radioactive element and frame. 
         FIG. 25  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 26  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 27  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 28  is another example radioactive element and frame positioned in a body lumen. 
         FIG. 29  is a cross-section of another example radioactive element and frame. 
         FIG. 30  is a cross-section of another example radioactive element and frame. 
         FIG. 31  is a cross-section of another example radioactive element and frame. 
         FIG. 32  is a cross-section of another example radioactive element and frame. 
         FIG. 33  is a perspective view of an example stent. 
         FIG. 34  is a perspective view of the stent member shown in  FIG. 33 . 
         FIG. 35  is a perspective view of the stent member shown in  FIG. 33 . 
         FIG. 36  is a perspective view of the stent member shown in  FIG. 33 . 
     
    
    
     While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the disclosure to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure. 
     DETAILED DESCRIPTION 
     For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. 
     All numeric values are herein assumed to be modified by the term “about”, whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value (e.g., having the same function or result). In many instances, the terms “about” may include numbers that are rounded to the nearest significant figure. 
     The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5). 
     As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
     As used herein, the terms “distal” or “distally” are referents to a direction away from an operator of the devices of the present disclosure, while the terms “proximal” or “proximally” are referents to a direction toward the operator of the devices of the present disclosure. 
     It is noted that references in the specification to “an embodiment”, “some embodiments”, “other embodiments”, etc., indicate that the embodiment described may include one or more particular features, structures, and/or characteristics. However, such recitations do not necessarily mean that all embodiments include the particular features, structures, and/or characteristics. Additionally, when particular features, structures, and/or characteristics are described in connection with one embodiment, it should be understood that such features, structures, and/or characteristics may also be used connection with other embodiments whether or not explicitly described unless clearly stated to the contrary. 
     The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure. 
     Treatment of abnormal tissue growth (e.g. cancer) may be accomplished through a variety of methodologies. For example, treatment of cancer may include the placement and deployment of a radioactive element adjacent to the diseased tissue. However, in some instances treatment outcomes may be improved by tailoring one or more conventional therapies. For example, positioning radioactive elements in a particular location relative to diseased tissue may improve cancer treatment outcomes as compared to either stent or radiation therapy alone. Therefore, it may be desirable to utilize materials and/or design a medical device that permits radioactive elements to be positioned in specific locations relative to diseased tissue. Some of the examples and methods disclosed herein may include a medical device that can position radioactive elements within a central region of a body lumen. 
     Medical devices disclosed herein may treat esophageal cancers. Additionally, the medical device may treat other forms of disease, including gastrointestinal, airway, urethra, ureter, cardiac, brain, breast, bladder, kyphoplasty and peripheral vascular disease, for example. Further, the medical devices disclosed herein may also be used in excisional cavities in solid and/or hollow organs. 
       FIG. 1  shows an example radioactive device  10  positioned within an example body lumen  12 . Radioactive device  10  may include one or more radioactive elements  20  secured to an example frame  14 . In some examples, radioactive device  10  may further include one or more support members  16  (e.g., arms) extending away from frame  14 . Additionally, radioactive device  10  may include a retrieval member  18  attached to an end region of radioactive device  10 . 
     As stated above, in at least some examples one or more radioactive elements  20  may be secured to example frame  14 . Further, it is contemplated that frame  14  may include a variety of designs, all of which may secure radioactive elements  20  along at least a portion of frame  14 . It is noted that for purposes of this disclosure, the term “frame” may be defined as a base, base member, housing, framework, support structure, scaffold, tubular member, reservoir, receptacle, etc. It is further noted that for purposes of this disclosure, “securing” radioactive elements to frame  14  may include attaching, coupling, fixing, receiving, holding, maintaining, containing, and/or disposing radioactive elements  20  along a portion of frame  14  in a removable or permanent manner. 
     In some instances, frame  14  may include a wire and/or mesh framework (e.g., scaffold) designed to secure radioactive elements  20  thereupon. In some examples, frame  14  may substantially surround radioactive elements  20 , providing a lumen or cavity to receive radioactive elements  20  therein. In other examples, frame  14  may only extend around a portion of radioactive elements  20 , providing a securement region for receiving radioactive elements therealong. It can be appreciated that wire frame structure  14  may include a variety of different geometries, patterns, configurations and/or designs configured to secure radioactive elements  20  thereupon. 
     In some examples frame  14  may be designed such that it forms a tubular structure. For example, frame  14  may include a tubular member having a lumen  24  extending therein. It can be appreciated that radioactive elements  20  may be positioned inside at least a portion of a tubular frame  14 . In some instances, a proximal end of lumen  24  may be open to receive radioactive elements  20  therein while a distal end of lumen  24  may be closed or blocked to prevent radioactive elements  20  from exiting the distal end of lumen  24 . 
     Frame  14  may be constructed from a variety of materials. For example, frame  14  may be constructed from a metal (e.g., Nitinol, stainless steel, etc.). In other instances, frame  14  may be constructed from a polymeric material (e.g., PET, polyamide, PEEK, etc.). In yet other instances, frame  14  may be constructed from a combination of metallic and polymeric materials. Additionally, frame  14  may include a bioabsorbable and/or biodegradable material, if desired. 
       FIG. 2  shows an example radioactive element  20  which may be secured to example frame  14 . In some instances, radioactive element  20  may be referred to as a “seed.” The terms “radioactive element” and “seed” may be used interchangeably throughout the remainder of this discussion. In general, seed  20  may be positioned adjacent a target site, whereby seed  20  may release radioactive energy and/or material, thereby radioactively treating the target location. 
     Seed  20  may be generally shaped as shown in  FIG. 2 . In other words, seed  20  may be an elongated cylinder having rounded ends. However, other shapes are contemplated. For example, seed  20  may be spherical, ovular, rectangular, triangular, or the like. 
       FIG. 2  shows the length of seed  20  depicted as dimension “X” and the diameter of seed  20  as dimension “D.” Depending on the particular therapeutic application, different types of seeds may have different dimensions. For example, in some instances, seed  20  may have a length “X” of between 1 and 20 mm. In other examples, seed  20  may have a length “X” between 2 and 10 mm, or between 3 and 8 mm. In some examples, seed  20  may have a length of about 4.5 mm. 
     Additionally, in some instances, seed  20  may have a diameter “D” of between 0.1 and 1.5 mm. In other examples, seed  20  may have a diameter “D” between 0.2 and 1 mm, or between 0.3 and 0.8 mm. In some examples, seed  20  may have a diameter of about 0.5 mm. 
     Seed  20  may include a variety of radioactive materials and or combinations of various materials. For example, seed  20  may include Iodine-125 (e.g. GE Oncura THINSeed™, IsoAid Advantage™ by IsoAid, Best™ Iodine-125), Palladium-103 (e.g. CivaString™ by CivaTech Technology, Theraseed™ by Theragenics, Best™ Palladium-103), Cesium-131, Gold-198, Iridium-192 and/or Ytterbium-169 or any other variations and/or derivatives thereof. Further, seed  20  may include other types of radioactive material. Additionally, seed  20  may include beta-emitting radionuclides. 
     In some instances, one or more seeds  20  may combined with one or more additional seeds  20  and/or one or more spacing elements to form an elongated treatment member  28 . For example,  FIG. 3  shows elongated treatment member  28  including seeds  20  and spacing elements  22  positioned between adjacent seeds  20 . In some instances (including the following discussion herein), treatment member  28  may be referred to as a “strand.” In some instances, treatment member  28  (i.e., strand) may include a plurality of seeds  20  arranged adjacent to one another and/or spaced away from one another, without spacing elements  22  therebetween. 
     The example shown in  FIG. 3  depicts a covering  30  surrounding the seeds  20  and spacers  22 . In some instances, covering  30  may include a material capable of being placed over the combination of seeds  20  and/or spacers  22  to form a continuous strand  28 . In some examples, covering  30  may be a tubular sleeve having an inner diameter in an equilibrium state less than the diameter of seeds  20  and/or spacers  22 . Accordingly, placement of seeds  20  and/or spacers  22  in the tubular sleeve expands regions of covering  30  surrounding seeds  20  and/or spacers  22 . In some examples, covering  30  may include one or more of a variety of shrink tubing (e.g. a polymeric tubing capable of reducing in size upon the application or heat, for example). In other examples, the covering may include a bioabsorbable and/or biodegradable material. Additionally, in some instances seeds  20  and/or spacers  22  may be connected to one another via a bioabsorbable connector. In other words, a combination of seeds  20  and/or spacers  22  may be “linked” to one another by a bioabsorbable and/or biodegradable material. In some instances, the radioactive strand  28  may include a radioactive wire. 
     Seeds  20  and spacers  22  may be spaced and/or distributed in various patterns and/or distributions along strand  28 . The length of the spacers  22  (which may correspond to the space between any two seeds  20 ) may vary depending on the particular strand  28  configuration. Similarly, the length of a given seed  20  in combination with a variety of lengths of given spacers  22  may vary depending on a particular strand  28  configuration. For example, it is contemplated that a given strand  28  may combine seeds  20  and/or spacers  22  in a variety of different combinations, patterns, distributions, separations, arrangements, or the like depending on the particular strand design required for a particular therapeutic application or user preference, for example. 
     For purposes of this disclosure, it is understood that radioactive elements  20  may include any of the variations of the radioactive seeds  20  and/or strands  28  discussed above. For example, frame  14  may be secured to any of the example seeds  20  and/or strands  28  discussed herein. In some examples, radioactive seeds  20  may be connected together to form a flexible or rigid elongate member (e.g., a rod). 
     In some instances, radioactive elements  20  may be removably secured to frame  14  such that radioactive elements  20  may be replaced with new radioactive elements in situ. For example, frame  14  may be initial implanted in body lumen  12  with radioactive elements  20 . Over a period of time in which radioactive elements  20  decay, it may be desirable to replace radioactive elements  20  with new radioactive elements to continue and/or alter the treatment to the target site of body lumen  12 . Accordingly, radioactive elements  20  may be removed from frame  14  while frame  14  remains implanted in body lumen  12  at the treatment site and new radioactive elements  20  delivered to the treatment site and secured to frame  14 . 
     As discussed above, radioactive device  10  may include one or more support members or arms  16 , or a plurality of support arms  16  designed to position device  10  at a particular location within a body lumen. For example, in some instances it may be desirable to position radioactive elements  20  in a central region of an example body lumen, such as near the central longitudinal axis of the body lumen.  FIG. 4  shows a cross-section of medical device  10  along line  4 - 4  of  FIG. 1 . As illustrated in  FIG. 4 , medical device  10  may include three support arms  16  extending radially away from frame  14 . Support arms  16  may include a first end  34  secured to frame  14  and a second end  32  engagable to an inner surface  36  of body lumen  12 . Thus, support arms  16  may extend radially outward from frame  14  toward inner surface  36  of body lumen  12 . In some instances, the support arms  16  may extend radially outward at an oblique angle to the central longitudinal axis of frame  14 . For example, support arms  16  may extend radially outward from frame  14  in a distal direction at an oblique angle, such that support arms  16  prevent distal migration of device  10  in a body lumen. In other instances, support arms  16  may extend radially outward from frame  14  in a proximal direction at an oblique angle. In other instances, support arms  16  may extend radially outward at a substantially perpendicular angle (i.e., 90°±5°, 90°±3°, or 90°±1°) to the central longitudinal axis of frame  14 . 
     It can be appreciated that three support arms  16  shown in  FIG. 4  (spaced substantially equidistant around frame  14 ) may position radioactive element  20  (shown in  FIG. 4  secured to frame  14 ) substantially in a central region of the body lumen  12 . However, it can be appreciated that radioactive device  10  may include more or less than three support members  16 . For example, radioactive device may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more support members  16 . Furthermore, it can be appreciated that support members  16  may be spaced around example frame  14  in a variety of configurations and/or arrangements. 
       FIGS. 1 and 4  depict support arms  16  having a length (depicted as “W” in  FIG. 4 ) extending between frame  14  and the inner surface  36  of body lumen  12 . Further, in  FIGS. 1 and 4 , each of the support arms  16  are shown to extend an equidistance between frame  14  and the inner surface  36  of body lumen  12 , thereby positioning radioactive elements  20  in the central region of body lumen  12 , such as centrally positioning the radioactive elements  20  equidistant to the perimeter of the inner surface  36  of the body lumen  12  (e.g., centering the radioactive elements  20  along the central longitudinal axis of the body lumen  12 ). In some examples, the distance “W” may be between 0.1 mm and 30 mm, or between about 1 mm and 20 mm, or between about 3 mm and 20 mm. 
     In at least some examples, it is further contemplated that one or more of support arms  16  may have differing lengths. Therefore, it can be appreciated that radioactive elements  20  may be positioned in a variety of locations within lumen  12  by altering the lengths, angular orientation from the longitudinal axis of frame  14  and/or body lumen  12  and/or arrangements of various support arms  16 . For example, by designing one or more of the support arms  16  to have a length different than other support arms  16 , the radioactive elements  20  may be positioned “off center” in body lumen  12 . In other words, it is contemplated that altering the dimensions of support arms  16  may shift the radioactive element away from the central longitudinal axis of the body lumen  12  and closer to the inner surface  36  of body lumen  12  on one side of the central longitudinal axis than on an opposite side of the central longitudinal axis of the body lumen. 
     In some instances, it may be desirable for the radioactive device  10  disclosed in the above examples to be inserted into body lumen  12  over a guidewire.  FIG. 5  shows that in some examples frame  14  and/or radioactive elements  20  may include a lumen  24  through which a guidewire may be inserted such that the radioactive device  10  may be advanced to a treatment location within body lumen  12  along a guidewire. It can be appreciated that lumen  24  may extend through each radioactive element  20  and/or the frame  14  along the entire axial length of medical device  10 , in some instances. In other instances, the frame  14  may include a guidewire lumen offset from radioactive elements  20  through which a guidewire may be disposed. 
       FIG. 6  illustrates medical device  10  (including frame  14 , support arms  16  and radioactive elements  20 ) positioned within the lumen  38  of an example delivery catheter  40 . As shown in  FIG. 6 , it is contemplated that support arms  16  may be able to flex, bend, rotate and/or collapse in a radial direction, an axial direction or both a radial and axial direction relative to frame  14  and/or radioactive elements  20 . For example,  FIG. 6  shows support arms  16  collapsed to fit within lumen  38  of catheter member  40 . 
     It is further contemplated that in any of the examples disclosed herein, support arms  16  may include one or more structural elements that allow it to flex, bend, rotate and/or collapse in a radial direction, an axial direction or both a radial and axial direction relative to frame  14  and/or radioactive elements  20  for delivery and/or retrieval. For example, support arms  16  may include one or more spring elements (not shown) which permit support arms  16  to bend in a variety of directions, moving support arms  16  closer to the central longitudinal axis of frame  14 . Further, the spring elements may allow the support arms  16  to shorten or lengthen relative to frame  14  and/or radioactive elements  20 . 
     In some examples, support arms  16  may be biased to shift from the collapsed position (shown in the delivery catheter of  FIG. 6 ) to a deployed position. For example,  FIG. 7  shows a portion of device  10  (including frame  14 , support arms  16  and radioactive elements  20 ) positioned within the lumen  38  of an example delivery catheter  40 . However,  FIG. 7  further shows a portion of device  10  which has been advanced out of the end of delivery catheter  40 . As shown in  FIG. 7 , support arms  16  which have been advanced out of catheter  40  have flexed radially away from frame  14  (and radioactive elements  20 ) to a position in which they contact the inner surface  36  of body lumen  12 . It can be appreciated that that support arms  16  may be designed with this “outward bias” such that they may expand radially away from frame  14  as medical device  10  is deployed out of an example delivery system (e.g., delivery catheter  40 ). In other words, support arms  16  may be configured to expand, extend and/or deflect radially outward from frame  14  when unconstrained. 
     Additionally,  FIG. 7  includes a detail view illustrating an end region  32  of support arm  16  contacting the inner surface  36  of body lumen  12 . As shown in  FIG. 7 , the end region  32  of support arm  16  may include an attachment member  42 . Attachment member  42  may include a hook, extension, arm, fastener, projection, prong, spur or similar structure designed to grip the inner surface  36  of body lumen  12 . For example, the detailed view in  FIG. 7  shows attachment member  42  piercing the inner surface  36  of body lumen  12 , and thus penetrating into the wall of body lumen  12  to anchor medical device  10  to body lumen  12 . It can be appreciated that when attachment member  42  penetrates (e.g., pierces) the inner surface  36  of body lumen  12 , medical device  10  may have an increased ability to maintain its position relative to a target site and/or body lumen  12  to prevent migration of device  10  in body lumen  12 . 
     Further, in some examples, attachment member  42  may be designed to be releasably attached to the inner surface  36  of body lumen  12 . In other words, in some examples medical device  10  may be designed such that attachment arms  16  may be deployed and thereby attachment members  42  may be inserted into the wall of body lumen  12 . After deployment, attachment arms  16  may be retracted (e.g., collapsed, withdrawn, etc.), thereby removing attachment members  42  from the wall of body lumen  12  and allowing medical device to be captured within a delivery and/or retrieval device for repositioning within or removal from a patient&#39;s body lumen. In other instances, attachment arms  16  may be detached from support arms  16  to permit removal of medical device  10  from body lumen  12 . 
       FIG. 8  illustrates an example radioactive medical device  10  (including frame  14 , support arms  16  and radioactive elements  20 ) designed to be removed from and/or repositioned within example body lumen  12 . As shown in  FIG. 8 , example medical device  10  includes one or more tethers  43  extending from retrieval member  18  to each of the attachment arms  16 . In some examples, tethers  43  may include wires, strings, etc. that extend along or are integrated with frame  14  and/or radioactive elements  20 . 
     As shown in  FIG. 8 , tethers  43  may include a first end that may be attached and/or coupled to retrieval member  18  and a second end that is attached and/or coupled to attachment members  16 . It can be appreciated that pulling retrieval member  18  (as depicted by the arrow parallel to body lumen  12  in  FIG. 8 ) may pull tethers  43 , which in turn may pull attachment arms  16  inward toward frame  14  and radioactive elements  20  (as depicted by the curved arrows in  FIG. 8 ). It can be appreciated that while  FIG. 8  shows tethers  43  positioned parallel and orthogonal to frame  14 , a variety of different designs may be implemented within the design of medical device  10  to permit retrieval member  18  to collapse attachment arms  16  inwardly toward frame  14  via tethers  43 . 
     In some instances, it may be desirable to remove and or replace radioactive elements  20  from frame  14 . For example, in some instances it may be desirable for a clinician to replace radioactive elements that have decayed to levels which are no longer beneficial to the treatment of diseased tissue and/or replace radioactive elements for a modified medical treatment. 
       FIG. 9  illustrates an example radioactive medical device  110  including attachment arms  116  secured to frame member  114 . The attachment arms  116  and frame  114  shown in  FIG. 9  may be designed and operate similarly to the attachment arms  16  and frame  14  discussed above with respect to  FIGS. 1-8 . Additionally, medical device  110  includes radioactive elements  120  secured to removable and/or replaceable cartridge member  115 . For example, cartridge member  115  may be a tubular member within which radioactive elements  120  may be secured. However, it is contemplated that cartridge member  115  may include a variety of structures designed to secure radioactive elements  120 . 
     It can be appreciated from  FIG. 9  that cartridge  115  may be removed (e.g., separated) from frame  114 . In other words, cartridge  115  may be designed to mate with frame  114  such that cartridge  115  may slide and/or insert into frame  114 . Additionally, medical device  110  may include a retrieval member  118  attached to cartridge  115 . In some examples, retrieval member  118  may form a unitary member with cartridge  115 . Retrieval member  118  may be designed to allow a clinician to grasp and manipulate cartridge  115  with a secondary medical instrument. It can be appreciated that frame member  114  may remain in a body lumen while cartridge  115  is removed and re-inserted within frame  114  upon replacing radioactive elements  20  in cartridge  115  with new radioactive elements  20 , or removed and replaced with another cartridge  115  containing new radioactive elements  20 . 
       FIG. 10  illustrates another example radioactive medical device  210 . Radioactive medical device  210  may include frame member  214 , support members  216  and radioactive elements  220  as described above with respect to  FIGS. 1-9 . Additionally,  FIG. 10  illustrates an anchoring member  217  that substantially surrounds at least a portion of medical device  210 . In some instances, anchoring member  217  may surround all of medical device  210 . 
     Anchoring member  217  may define a variety of designs and or structures. For example, anchoring member  217 , such as a framework or scaffold, which may be an expandable framework or expandable scaffold in some instances, may include a stent, such as an expandable stent, a self-expanding stent, or another endoprosthesis or tubular member, for example. In some instances, anchoring member  217  may be manufactured from a single, cylindrical tubular member. For example, in some instances, a cylindrical tubular member may be laser cut to form an expandable stent. Anchoring member  217  may include one or more struts arranged in various designs and/or patterns. For example, anchoring member  217  may be a laser cut stent formed from a unitary tubular member. Therefore, numerous designs, patterns and/or configurations for the stent cell openings, strut thicknesses, strut designs, stent cell shapes are contemplated and may be utilized with embodiments disclosed herein. In other instances, anchoring member  217  may be a woven, braided or knitted tubular member, such as an expandable stent (e.g., self-expanding stent) formed from one or more, or a plurality of interwoven wire filaments. 
     As shown in  FIG. 10 , attachment arms  216  may extend away from radioactive elements  220  and attach to anchoring member  217 . For example, each of attachment arms  216  may include a first end  234  secured to frame member  214  and/or radioactive elements  220  and a second end  232  attached to anchoring member  217 . 
     It can be appreciated that medical device  210  (including frame member  214 , support members  216 , radioactive elements  220  and anchoring member  217 ) may be delivered to a target site in example body lumen  212  via a delivery system similar to that described with respect to  FIGS. 6 and 7 . However, medical device  210  may further include collapsing anchoring member  217  (in addition to frame member  214 , support members  216  and radioactive elements  220 ) collapsed inside a delivery catheter. It can be appreciated that in some examples that as medical device  210  is deployed out of a delivery catheter, the anchoring member  217  may self-expand, thereby expanding (e.g., flexing outward) support arms  216  and positioning frame  217  and radioactive elements  220  in a central region of body lumen  212 , such as near the central longitudinal axis of body lumen  212 . For instance, each of the support arms  216  may extend an equidistance between frame member  214  and the anchoring member  217  such that frame member  214  (and radioactive elements  220 ) is centered along the central longitudinal axis of anchoring member  217 , thereby positioning radioactive elements  220  in the central region of anchoring member  217  and body lumen  212 , such as centrally positioning the radioactive elements  220  equidistant to the perimeter of the inner surface of the body lumen  212  (e.g., centering the radioactive elements  220  along the central longitudinal axis of anchoring member  217  and the body lumen  212 ). 
       FIG. 11  illustrates another example radioactive medical device  310 . As shown in  FIG. 11 , radioactive medical device  310  includes a frame  314 , radioactive elements  320  and anchoring member  317  which may be similar in structure to the frame, radioactive elements, and the anchoring member described in the examples above. However,  FIG. 11  further shows attachment arms  316  extending between anchoring member  317  and frame  314 . 
     Attachment arms  316  may be similar in structure to the attachment arms described in the examples above. However, in some examples attachment arms  316  may further include a securement structure  322  that substantially surrounds frame  314  and radioactive elements  320 . In some examples, securement structure  322  may include an eyelet, loop, hoop, ring, etc. that forms an aperture through which frame and/or radioactive elements  320  may extend. As described above (and shown in  FIG. 11 ), attachment arms  316  may be designed such that they position, suspend, locate, etc. frame  314  (including radioactive elements  320 ) in a central region of anchoring member  317  and example body lumen  312 , such as near the central longitudinal axis of body lumen  312 . For instance, attachment arms  316  may extend radially outward from frame  314  to anchoring member  317  such that frame  314  (and radioactive elements  320 ) is centered along the central longitudinal axis of anchoring member  317 , thereby positioning radioactive elements  320  in the central region of anchoring member  317  and body lumen  312 , such as centrally positioning the radioactive elements  320  equidistant to the perimeter of the inner surface of the body lumen  312  (e.g., centering the radioactive elements  320  along the central longitudinal axis of anchoring member  317  and the body lumen  312 ). 
     Additionally,  FIGS. 11 and 12  illustrate that in some examples, radioactive medical device  310 , may include a plurality of attachment arms  316 , such as two attachment arms  316  that may be aligned along the longitudinal axis of medical device  310 . For example,  FIG. 12  is a cross-section along line  12 - 12  of  FIG. 11  illustrating that each attachment arm  316  may include an attachment point along anchoring member  317 , whereby the two attachment points may be aligned longitudinally. 
       FIG. 13  is an example cross-section illustrating that in at least some examples contemplated herein medical device  310  may include more than one attachment arm  316  extending between anchoring member  317  and frame  314 . It can be appreciated that multiple attachment arms  316  may be arranged in a variety of configurations. For example, in some examples, two or more attachment arms  316  may extend away from anchoring member  317  and secure to frame  314  at a single point. In other examples, multiple attachment arms  316  may be positioned at various points along the longitudinal axis of medical device  310  and be secured to frame  314  at various points along the longitudinal axis of frame  314 . Furthermore, it is contemplated that in some examples, one or more attachment arms  316  may be longitudinally aligned (as shown in  FIGS. 11-13 . However, it is contemplated that in other examples one or more attachment arms may not be longitudinally aligned. 
     Additionally, while the examples disclosed above may depict radioactive medical device as including two or more attachment arms, it is contemplated that any of the examples disclosed herein may include only a single attachment arm extending between either the body lumen or anchoring member and the frame (including radioactive elements). 
     In some instances, it may be desirable for a radioactive medical device to shift from a position in a central region of body lumen to a position in which the medical device is closer to the inner surface of the body lumen. For example, in some instances it may be desirable for medical device  310  (shown in  FIG. 11 ) to be able to shift in response to bodily material (e.g., food, vomit, etc.) moving through the esophagus or other body lumen within which the medical device  310  is positioned. For example, in any of the examples described herein, attachment arms coupling a frame member to either the body lumen or an anchoring member may include one or more deflectable elements which may allow the attachment arms to shift in a variety of directions. 
       FIGS. 14 and 15  illustrate an example radioactive medical device  310  designed to shift along the longitudinal axis of medical device  310 . As shown by the arrows in  FIG. 14 , attachment arms  316  may be designed such that they can flex, bend, rotate, deflect, etc. in a longitudinal direction, a radial direction, or both a longitudinal and radial direction. For example,  FIG. 15  illustrates that in some examples frame member  314  may shift in a longitudinal direction such that frame  314  is positioned along anchoring member  317 .  FIG. 16  is a cross-section along line  16 - 16  of  FIG. 15  illustrating the position of frame  314  (including radioactive elements  320 ) shifted such that frame  314  is positioned along anchoring member  317 . 
     Additionally, while  FIGS. 14-16  depict frame  314  (including radioactive elements  320 ) shifting along the longitudinal axis of medical device  310 , some other examples contemplate frame  314  (including radioactive elements  320 ) shifting along the radial axis of radioactive medical device  310 .  FIG. 17  depicts frame member  314  shifting along the radial axis such that frame  314  (including radioactive elements  320 ) are positioned along anchoring member  317 . 
       FIG. 18  illustrates another example radioactive medical device  410 . As shown in  FIG. 18 , radioactive medical device  410  may include radioactive elements  420  and an anchoring member  417 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. Additionally,  FIG. 18  further shows attachment arms  416  extending radially inward of the anchoring member  417 . 
     Attachment arms  416  may be similar in structure to the attachment arms described in the examples above. The attachment arms  416  may be designed such that they position, suspend, locate, etc. the radioactive elements  420  in a central region of anchoring member  417  and example body lumen  412 , such as around the central longitudinal axis of body lumen ix)  412 . For example, attachment arms  416  may extend radially outward from the radioactive elements  420  to anchoring member  417  such that the radioactive elements  420  are centered around the central longitudinal axis of anchoring member  417 , thereby positioning radioactive elements  420  in the central region of anchoring member  417  and body lumen  412 , such as centrally positioning the radioactive elements  420  equidistant to the perimeter of the inner surface of the body lumen  412  (e.g., centering the radioactive elements  420  around the central longitudinal axis of anchoring member  417  and the body lumen  412 ). 
     It can be appreciated that positioning the radioactive elements  420  around the central axis of the body lumen  412  may permit fluids and other material to more easily flow through the medical device  410 , while still permitting the radioactive elements to maintain a position within body lumen  412  to effectively treat the target tissue. 
       FIG. 19  is a cross-sectional view taken along line  19 - 19  of  FIG. 18 .  FIG. 19  shows attachment arms  416  extending radially inward of the anchoring member  417 .  FIG. 19  further illustrates attachment arms  416  positioning the radioactive elements  420  in a central region of anchoring member  417  and example body lumen  412 , such as around the central longitudinal axis  435  of body lumen  412 . 
     It can be appreciated that  FIG. 19  illustrates four support arms  416  spaced substantially equidistant around the central longitudinal axis  435  of body lumen  412 . This configuration may position the four radioactive elements  420  substantially in a central region of the body lumen  412 . However, it may be appreciated that radioactive device  410  may include more or less than four support members  416  and four radioactive elements  420 . For example, radioactive device  410  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more support members  416  and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more radioactive elements  420 . Furthermore, it can be appreciated that support members  416  may be spaced around example support member  417  in a variety of configurations and/or arrangements. Additionally, in other examples it is contemplated that there may be one or more rows of radioactive elements  420  spaced around support member  417  in a variety of configurations and/or arrangements. 
     In some instances, it may be desirable for a radioactive medical device to shift from a position in a central region of body lumen to a position in which the radioactive elements are closer to the inner surface of the an anchoring member (e.g., expandable stent member) in which it is positioned. For example, in some instances it may be desirable for medical device  410  (shown in  FIG. 18  and  FIG. 19 ) to be able to shift in response to being loaded into a medical device delivery system. 
       FIG. 20  illustrates an example medical device delivery system  450 . Medical device delivery system  450  may include a distal end  456  and a proximal end  458 . Medical device delivery system  450  may include an inner tubular member  452  and an outer tubular member  454 . The inner tubular member  452  may extend through a lumen of the outer tubular member  454 . In other words, the outer tubular member  454  may be disposed over the inner tubular member  452 . Additionally, it can be appreciated that the outer tubular member  454  may be able to translate with respect to the inner tubular member  452 . For example, the outer tubular member  454  may be able to translate (e.g., shift, slide, etc.) in a distal-to-proximal direction with respect to the inner tubular member  452 . 
       FIG. 20  further illustrates the medical device  410  shown in  FIG. 18  and  FIG. 19  positioned between the outer tubular member  454  and the inner tubular member  452 . It can be appreciated that the medical device  410  may be in a “pre-deployed” (e.g., “loaded”) configuration when positioned between the outer tubular member  454  and the inner tubular member  452 . It can further be appreciated that translating the outer tubular member  454  in a distal-to-proximal direction may “release” (e.g., “deploy”) the medical device  410 . 
       FIG. 21  is a cross-sectional view along line X-X of  FIG. 20 .  FIG. 20  shows medical device  410  positioned between the outer tubular member  454  and the inner tubular member  452  in a pre-deployed (e.g., loaded) configuration.  FIG. 21  further illustrates that attachment arms  416  may be designed such that they can flex, bend, rotate, deflect, etc. such that they move radially outward and closer to the inner surface of the anchoring member  417 . For example,  FIG. 21  illustrates that attachment arms  416  may shift such that the radioactive elements  420  may be adjacent to both the inner surface of the anchoring member  417  and the outer surface of the inner tubular member  452  of the medical device delivery system  450 . It can further be appreciated that the medical device  410  (including the attachment arms  416  and the radioactive elements  420 ) may return to the configuration shown in  FIG. 19  after being released (e.g., deployed) from the medical device delivery system  450 . 
       FIG. 22  illustrates another example radioactive medical device  510 . As shown in  FIG. 22 , radioactive medical device  510  may include radioactive elements  520  and an anchoring member  517 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. However,  FIG. 22  further shows attachment arms  516  extending radially inward of the anchoring member  517 . Additionally, the attachment arms  516  shown in  FIG. 22  may include a “zig-zag” configuration. As illustrated the, attachment arms  516  may include one or more bends and/or angles that may allow the attachment arms  516  to flex similar to a spring. While not shown in  FIG. 22 , it is contemplated that more than one attachment arm  516  may extend from the anchoring member to the radioactive element. An example of this configuration is shown in  FIG. 24 , however, the attachment arms shown in  FIG. 24  are curved (versus the zig-zag configuration shown in  FIG. 22 ). 
       FIG. 23  illustrates another example radioactive medical device  610 . As shown in  FIG. 23 , radioactive medical device  610  may include radioactive elements  620  and an anchoring member  617 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. However,  FIG. 23  further shows attachment arms  616  extending radially inward of the anchoring member  617 . Additionally, the attachment arms  616  shown in  FIG. 23  may include a single “bent-arm” configuration. As illustrated the, attachment arms  616  may include a bend or angle that may allow the attachment arms  616  to flex similar to a spring. While not shown in  FIG. 23 , it is contemplated that more than one attachment arm  616  may extend from the anchoring member to the radioactive element. An example of this configuration is shown in  FIG. 24 , however, the attachment arms shown in  FIG. 24  are curved (versus the bent-arm configuration shown in  FIG. 23 ). 
       FIG. 24  illustrates another example radioactive medical device  710 . As shown in  FIG. 24 , radioactive medical device  710  may include radioactive elements  720  and an anchoring member  717 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. However,  FIG. 24  further shows attachment arms  716  extending radially inward of the anchoring member  717 . Additionally, the attachment arms  716  shown in  FIG. 24  may include one or more a curved arms attached to the radioactive elements  720 . As illustrated the, attachment arms  720  may include a curved shape which may allow the attachment arms  716  to flex radially inward/outward. 
       FIG. 25  illustrates another example radioactive medical device  810 . Radioactive medical device  810  may include frame members  814 , support members  816  and radioactive elements  820 . Additionally,  FIG. 25  illustrates an anchoring member  817  that substantially surrounds at least a portion of medical device  810 . In some instances, anchoring member  817  may surround all of medical device  810 . While  FIG. 25  shows two frame members  814 , it is contemplated that medical device  810  may include more or less than two frame members  814 . For example, medical device  810  may include 1, 2, 3, 4, 5, 6 or more frame members  814  (including radioactive elements  820 ). 
     Anchoring member  817  may define a variety of designs and or structures. For example, anchoring member  817 , such as a framework or scaffold, which may be an expandable framework or expandable scaffold in some instances, may include a stent, such as an expandable stent, a self-expanding stent, or another endoprosthesis or tubular member, for example. In some instances, anchoring member  817  may be manufactured from a single, cylindrical tubular member. For example, in some instances, a cylindrical tubular member may be laser cut to form an expandable stent. Anchoring member  817  may include one or more struts arranged in various designs and/or patterns. For example, anchoring member  817  may be a laser cut stent formed from a unitary tubular member. Therefore, numerous designs, patterns and/or configurations for the stent cell openings, strut thicknesses, strut designs, stent cell shapes are contemplated and may be utilized with embodiments disclosed herein. In other instances, anchoring member  817  may be a woven, braided or knitted tubular member, such as an expandable stent (e.g., self-expanding stent) formed from one or more, or a plurality of interwoven wire filaments. 
     As shown in  FIG. 25 , attachment arms  816  may extend away from the frame members  814  (including radioactive elements  820 ) and attach to anchoring member  817 . For example, each of attachment arms  816  may include a first end  834  secured to frame member  814  and/or radioactive elements  820  and a second end  832  attached to anchoring member  817 . 
     It can be appreciated that in some examples that medical device  810  may be configured to position the frame members  814  and radioactive elements  820  in a central region of body lumen  812 , such as near the central longitudinal axis of body lumen  812 . For instance, each of the support arms  816  may extend an equidistance between frame members ix)  814  and the anchoring member  817  such that frame members  814  (and radioactive elements  820 ) are centered along the central longitudinal axis of anchoring member  817 , thereby positioning radioactive elements  820  in the central region of anchoring member  817  and body lumen  812 , such as centrally positioning the radioactive elements  820  equidistant to the perimeter of the inner surface of the body lumen  812  (e.g., centering the radioactive elements  820  along the central longitudinal axis of anchoring member  817  and the body lumen  812 ). 
     It can be appreciated that positioning the frame members  814  and the radioactive members  820  around the central axis of the body lumen  812  may permit fluids and other material to more easily flow through the medical device  810 , while still permitting the radioactive elements  820  to maintain a position within body lumen  812  to effectively treat the target tissue. 
       FIG. 26  illustrates another example radioactive medical device  910 . As shown in  FIG. 26 , radioactive medical device  910  may include frame members  914  and radioactive elements  920  and an anchoring member  917 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. Additionally, the attachment arms  916  shown in  FIG. 26  may include a single “bent-arm” configuration. 
       FIG. 27  illustrates another example radioactive medical device  1010 . As shown in  FIG. 27 , radioactive medical device  1010  may include frame members  1014  and radioactive elements  1020  and an anchoring member  1017 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. Additionally, the attachment arms  1016  shown in  FIG. 26  may include a “zig-zag” configuration including multiple bends. 
       FIG. 28  illustrates another example radioactive medical device  1110 . As shown in  FIG. 28 , radioactive medical device  1110  may include a spiral-shaped frame member  1114  and radioactive elements  1120  and an anchoring member  1117 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. Further,  FIG. 28  shows attachment arms  1116  extending radially inward of the anchoring member  1117 . 
     As discussed above, the frame member  1114  shown in  FIG. 28  is substantially spiral shaped. For example,  FIG. 28  illustrates the frame member  1114  including one or more curved portions extending along frame member  1114 . It can be appreciated that a spiral-shaped frame member  1114  that is positioned around the central longitudinal axis of the body lumen  1112  may permit fluids and other material to more easily flow through the medical device  1110 , while still permitting the radioactive elements  1120  to maintain a position within body lumen  1112  to effectively treat the target tissue. For example,  FIG. 28  illustrates that the radioactive elements  1120  are spaced both around the central longitudinal axis of the body lumen  1112  and also spaced longitudinally along the body lumen  1112 . This configuration may provide substantially evenly-spaced radioactive treatment to a length of the body lumen, while also permitting bodily fluids and material to pass through the medical device  1110 , as discussed above. 
       FIG. 29  illustrates another example radioactive medical device  1210 . Similar to that described above,  FIG. 29  shows a cross-sectional view of radioactive medical device  1210  positioned within the example medical device delivery system  450  (described above with respect to  FIG. 20 ). For example,  FIG. 29  shows medical device  1210  positioned between inner tubular member  452  and outer tubular member  454  in a pre-deployed (e.g., loaded) configuration. 
     As shown in  FIG. 29 , radioactive medical device  1210  may include radioactive elements  1220  and an anchoring member  1217 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. However,  FIG. 29  further shows that medical device  1210  may include a foam spacer  1260  disposed between the inner tubular member  452  and the outer tubular member  454 . 
     In at least some examples, the radioactive elements  1220  may be coupled (e.g., attached, etc.) to the foam spacer  1260 . Further, while  FIG. 29  shows the radioactive elements spaced substantially evenly around the foam spacer  1260 , it is contemplated that the radioactive elements may be unevenly spaced around the foam spacer  1260 . It is further contemplated that one or more of the radioactive elements  1220  may be at least partially positioned within the foam spacer  1260 . For example, it is contemplated that one or more of the radioactive elements  1220  may be embedded within the foam spacer  1260 . While  FIG. 29  shows four radioactive elements  1220  positioned adjacent foam spacer  1260 , it is contemplated that medical device  1210  may include more or less than four radioactive elements  1260 . For example, medical device  1210  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more radioactive elements  1220 . 
     As can be appreciated from  FIG. 29 , the foam spacer  1260  may be in a compressed configuration when positioned within the medical delivery device  450 . In other words, in some examples the medical device  1210  (including the anchoring member  1217 , foam spacer  1260  and radioactive elements  1220 ) may be compressed radially inward to permit loading of the medical device  1210  into the stent delivery device  450 . 
       FIG. 30  illustrates the medical device  1210  in an expanded configuration. In other words,  FIG. 30  illustrates medical device  1210  after having been deployed (e.g., released) from the medical device delivery system  450 . As can be appreciated from  FIG. 30 , the anchoring member  1217  may expand radially outward after being released from the medical device delivery system  450 . Additionally, in some examples, the foam spacer may expand radially outward, radially inward or both radially inward and radially outward. 
     It can be appreciated that in some examples that medical device  1210  may be configured to position the radioactive elements  1220  in a central region of a body lumen (not shown in  FIG. 29  or  FIG. 30 ), such as near the central longitudinal axis of a body lumen. For instance, the foam spacer  1260  may be centered around the central longitudinal axis of anchoring member  1217 , thereby positioning radioactive elements  1220  in the central region of anchoring member  1217 , such as centrally positioning the radioactive elements  1220  equidistant to the perimeter of the inner surface of a body lumen (e.g., centering the radioactive elements  1220  around the central longitudinal axis of anchoring member  1217  and the body lumen). 
     It can be appreciated that positioning the foam spacer  1260  and the radioactive members  1220  around the central axis of the body lumen may permit bodily fluids and other material to more easily flow through the medical device  1210 , while still permitting the radioactive elements  1220  to maintain a position within body lumen  1212  to effectively treat the target tissue. 
       FIG. 31  illustrates another example radioactive medical device  1310 . Similar to that described above with respect to  FIG. 21 ,  FIG. 31  shows a cross-sectional view of radioactive medical device  1310  positioned within the example medical device delivery system  450  (described above with respect to  FIG. 20 ). For example,  FIG. 31  shows medical device  1310  positioned between inner tubular member  452  and outer tubular member  454  in a pre-deployed configuration. 
     As shown in  FIG. 31 , radioactive medical device  1310  may include radioactive elements  1320  and an anchoring member  1317 , which may be similar in structure to the radioactive elements and the anchoring members described in the examples above. However,  FIG. 31  further shows that medical device  1310  may include a plurality of foam spacers  1360  disposed between the inner tubular member  452  and the outer tubular member  454 . 
     In at least some examples, the radioactive elements  1320  may be coupled (e.g., attached, etc.) to the foam spacers  1360 . Further, while  FIG. 31  shows the radioactive elements  1320  spaced substantially evenly around the central longitudinal axis of the medical device  1310 , it is contemplated that the radioactive elements  1320  may be unevenly spaced around the central longitudinal axis of the medical device  1310 . It is further contemplated that one or more of the radioactive elements  1320  may be at least partially positioned within the foam spacers  1360 . For example, it is contemplated that one or more of the radioactive elements  1320  may be embedded within the foam spacers  1360 . While  FIG. 31  shows four radioactive elements  1320  positioned adjacent four foam spacers  1360 , it is contemplated that medical device  1310  may include more or less than four radioactive elements  1360  and four foam spacers  1360 . For example, medical device  1310  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more radioactive elements  1320  and foam spacers  1360 . 
     As can be appreciated from  FIG. 31 , the foam spacers  1360  may be in a compressed configuration when positioned within the medical delivery device  450 . In other words, in some examples the medical device  1310  (including the anchoring member  1317 , foam spacer  1360  and radioactive elements  1320 ) may be compressed radially inward to permit loading of the medical device  1310  into the stent delivery device  450 . 
       FIG. 32  illustrates the medical device  1310  in an expanded configuration. In other words,  FIG. 32  illustrates medical device  1310  after having been deployed (e.g., released) from the medical device delivery system  450 . As can be appreciated from  FIG. 32 , the anchoring member  1317  may expand radially outward after being released from the medical device delivery system  450 . Additionally, in some examples, the foam spacers  1360  may expand radially outward, radially inward or both radially inward and radially outward. 
     It can be appreciated that in some examples that medical device  1310  may be configured to position the radioactive elements  1320  in a central region of a body lumen (not shown in  FIG. 31  or  FIG. 32 ), such as near the central longitudinal axis of a body lumen. For instance, the foam spacers  1360  may be centered around the central longitudinal axis of anchoring member  1317 , thereby positioning radioactive elements  1320  in the central region of anchoring member  1317 , such as centrally positioning the radioactive elements  1320  equidistant to the perimeter of the inner surface of a body lumen (e.g., centering the radioactive elements  1320  around the central longitudinal axis of anchoring member  1317  and the body lumen). 
     It can be appreciated that positioning the foam spacers  1360  and the radioactive members  1320  around the central axis of the body lumen may permit fluids (e.g., food or liquid) and other material to more easily flow through the medical device  1310 , while still permitting the radioactive elements  1320  to maintain a position within the body lumen to effectively treat the target tissue. 
       FIG. 33  shows another example anchoring device  1410 . Medical device  1410  may include a stent member. Stent  1410  may include a plurality of filaments and/or strut members  1462  arranged in a variety of different designs and/or geometric patterns. For example, strut members  1462  may be a laser cut from a unitary tubular member. In other examples, filaments  1462  may be braided, woven, knitted or constructed using a combination of these (or similar) manufacturing techniques. Therefore, numerous designs, patterns and/or configurations for the stent cell openings, strut thicknesses, strut designs, stent cell shapes are contemplated and may be utilized with embodiments disclosed herein. 
     In some instances stent  1410  may be a self-expanding stent. A self-expanding stent may be delivered to a treatment area via a self-expanding stent delivery system. It is contemplated that the examples disclosed herein may be utilized with any one of various stent configurations, including, balloon expandable stents, such as a laser cut stent and/or a braided stent, a self-expanding stent, non-expandable stents, or other stents. 
     Stent filaments  1462  disclosed herein may be constructed from a variety of materials. For example, filaments  1462  may be constructed from a metal (e.g., Nitinol). In other instances, filaments  1462  may be constructed from a polymeric material (e.g., PET). In yet other instances, filaments  1462  may be constructed from a combination of metallic and polymeric materials. Additionally, filaments  1462  may include a bioabsorbable and/or biodegradable material. 
     Stent  1410  may include a first end region  1413 , a second end region  1415  and a body portion  1421 . Body portion  1421  may extend between the first end region  1413  and the second end region  1415 . Further, stent  1421  may include a lumen  1416  extending within at least a portion of the stent  1410 . Additionally,  FIG. 33  illustrates that the first end region  1413 , the second end region  1415  or both the first end region  1413  and the second end region  1415  may include a flared portion. 
     Further,  FIG. 33  illustrates that the stent member  1410  may include one or more channels  1418  extending from the first end region  1413  to the second end region  1415 . Each of the one or more channels  1418  may include a first end  1417  and a second end  1419 . While  FIG. 33  illustrates channels  1418  extending longitudinally along body portion  1421 , this is not intended to be limiting. Rather, it is contemplated that channels  1418  may be longitudinal, helical, circumferential or any other of a variety of configurations along the stent member  1410 . 
       FIG. 34  is a cross-section along line  34 - 34  of  FIG. 33 .  FIG. 34  illustrates four channels  1418  extending within the body portion  1421  of the stent  1410 . While  FIG. 34  illustrates four channels  1418  spaced around the circumference of the stent  1410 , it is contemplated that stent  1410  may include more or less than four channels  1418 . For example, stent  1410  may include 1, 2, 3, 4, 5, 6, 7, 8 or more channels  1418 . Additionally,  FIG. 34  illustrates that each of the channels  1418  may extend radially inward from the outer surface of the stent  1410 . 
     In some instances, it may be desirable to dispose a radioactive element along the stent member  1410 . For example,  FIG. 35  illustrates that stent member  1410  may include frame members  1414  and radioactive elements  1420  as described above. Further,  FIG. 35  illustrates that the frame members  1414  may be disposed within the channels  1418  of the stent member  1410 . Referring to  FIG. 33 , it is contemplated that the frame members  1414  (including the radioactive elements  1420 ) are positioned within the channels  1418  such that the ends of the frame members  1414  are adjacent the first end  1417  and the second end  1419  of each of the channels  1418 . In other words, the first end  1417  and the second end  1419  may prevent the frame members  1414  from extending into the flared portions of the first end region  1413  and the second end region  1415  of the stent member  1410 . 
     It can further be appreciated from  FIG. 35  that the design of the stent member  1410  permits the frame members  1414  (including the radioactive elements  1420 ) to be held adjacent a target tissue site (via positioning within the channels  1418 ) while also permitting for body fluids and other material to flow through the lumen  1416  of the stent  1410 . 
     In some examples, stent  1410  may include a covering  1464 . For example,  FIG. 36  illustrates that stent  1410  may be partially or fully covered by an elastomeric or non-elastomeric material. Additionally, stent  1410  may be partially or fully covered by a polymeric material such as silicone or ePTFE. Further, the covering (e.g., polymer)  1464  may span the spaces (e.g., openings, cells) created by the geometric arrangements of filaments  1462 . 
     It is further contemplated that in any of the examples disclosed herein, one or more structures of radioactive medical device  10  (or other examples thereof) may be designed to shield radioactive energy being emitted from radioactive elements  20  (or other examples thereof), thereby modulating the radiation delivered by radioactive elements. For example, frame  14  (or other examples thereof) and/or anchoring member  217  (or other examples thereof), may be designed such that they shield (e.g., modulate) the radioactive energy being emitted from radioactive elements  20  (or other examples thereof). For example, anchoring member  217  may include a stent strut (or stent strut pattern) that is designed to align with radioactive elements disclosed herein (for example, when radioactive elements  320  are shifted to be positioned along anchoring member  317 ) such that the stent struts themselves modulate the amount of radioactive energy being received by the target tissue. 
     Additionally, it is contemplated that in any of the example disclosed herein, all or a portion of frame  14  (or other examples thereof) and/or anchoring member  217  (or other examples thereof) may include a covering which incorporates a radiation shield, and thereby modulates the amount of radiation delivered by radiation elements positioned adjacent thereto. 
     Materials that may be used for the various components of the radioactive medical device  10  and the various examples disclosed herein may include those commonly associated with medical devices. For simplicity purposes, the following discussion makes reference to radioactive medical device  10 . However, this is not intended to limit the devices and methods described herein, as the discussion may be applied to other similar systems and/or components of stent systems or devices disclosed herein. 
     It should be understood that this disclosure is, in many respects, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps without exceeding the scope of the disclosure. This may include, to the extent that it is appropriate, the use of any of the features of one example embodiment being used in other embodiments. The disclosure&#39;s scope is, of course, defined in the language in which the appended claims are expressed.