Abstract:
A device for orienting a brachytherapy applicator implanted in a treatment cavity may include an elongated body defining an open channel adapted for slidably receiving at least a portion of a shaft or catheter body of a brachytherapy applicator. A manually engageable gripping element at an end of the elongated body is actuated to constrict at least a portion of the channel around a portion of the shaft to help prevent shaft twist and rotational movement between the elongated body and brachytherapy applicator. At least one engaging element on the elongated body is actuated to releasably engage at least one corresponding engaging element on a brachytherapy applicator. Shaft twist and rotational discontinuity between the elongated body and brachytherapy applicator are further prevented when the at least one engaging element of the elongated body engages the at least one corresponding element of the brachytherapy applicator. The device can advantageously be mounted and removed while the applicator is inside the treatment cavity. Furthermore, the device is an “external tool” that engages the brachytherapy applicator externally about its outer surface.

Description:
FIELD OF THE INVENTION 
       [0001]    This disclosure generally relates to the field of brachytherapy and, more particularly to orienting a brachytherapy treatment catheter within a treatment cavity, such as a breast lumpectomy cavity. 
       BACKGROUND OF THE INVENTION 
       [0002]    Malignant tumors are often treated by surgical resection to remove as much of the tumor as possible. Infiltration of the tumor cells into normal tissue surrounding the tumor, however, can limit the therapeutic value of surgical resection because the infiltration can be difficult or impossible to treat surgically. Radiation therapy can be used to supplement surgical resection by targeting the residual tumor margin after resection, with the goal of reducing its size or stabilizing it. Radiation therapy can be administered through one of several methods, or a combination of methods, including external-beam radiation, stereotactic radiosurgery, and brachytherapy. The term “brachytherapy,” as used herein, refers to radiation therapy delivered by a source of therapeutic rays inserted into the body at or near a tumor or other proliferative tissue disease site. 
         [0003]    A typical breast brachytherapy radiation treatment involves insertion of an applicator by a surgeon. A brachytherapy applicator may typically include a flexible catheter shaft with an inflatable balloon mounted on its distal end. One or more dosing lumens extend within the catheter shaft and into the balloon. The catheter shaft is inserted into a body so that the balloon is positioned within a resected cavity. The balloon is subsequently inflated and radioactive material, for example in the form of one or more radioactive seeds, is loaded into one or more of the dosing lumens for radiation delivery. The brachytherapy catheter system is removed upon completion of treatment. In single lumen brachytherapy treatment devices the dosing lumen is positioned along a central axis of the balloon such that substantially symmetrical isodose profiles may be achieved during treatment, i.e., a radiation dose of equal intensity is delivered to the tissue surrounding the balloon. In multi-lumen brachytherapy treatment devices one or more lumens are offset from the central axis within the balloon such that asymmetrical isodose profiles may be achieved during treatment, i.e., a radiation dose of greater intensity is delivered to certain areas of tissue surrounding the balloon in comparison to other areas, which receive a dose of lesser intensity. Proper orientation of the treatment device is desirable for delivering an asymmetric isodose profile. A physician may be able to make minor adjustments by applying direct rotational force to the shaft by hand. However, the catheter shaft may be ill-suited to transmitting torque. For example, a flexible shaft may initially twist in response to rotational force and then unpredictably untwist as applied resistance to twist increases and torque exceeds friction between the applicator and tissue. As a result, it is difficult to precisely orient the applicator. 
       SUMMARY 
       [0004]    In accordance with an aspect of the invention a device for orienting a brachytherapy applicator implanted in a treatment cavity includes an elongated body defining an open proximal end, an open distal end, and an open channel between the proximal and distal ends. The channel slidably receives at least a portion of a brachytherapy applicator during use. The device may include a manually engageable gripping element. The gripping element may be located at the proximal end of the elongated body, and be operable to constrict at least a portion of the channel to prevent rotational movement between the elongated body and a portion of a brachytherapy applicator inserted into the channel. The device may also include at least one engaging element disposed on a portion of the elongated body for releasably engaging at least one corresponding engaging element on the brachytherapy applicator, wherein the elongated body and brachytherapy applicator are prevented from rotating relative to each other when the at least one engaging element of the elongated body engages the at least one corresponding engaging element of the brachytherapy applicator. 
         [0005]    In accordance with another aspect of the invention a brachytherapy system includes a brachytherapy applicator for insertion into a treatment cavity and a device for orienting the brachytherapy applicator upon insertion into a treatment cavity. The brachytherapy applicator includes a flexible shaft defining a proximal end, a distal end and a shaft lumen extending between the proximal end distal ends, an inflatable member disposed about the distal end of the shaft, at least one dosing lumen extending through the shaft lumen and into the inflatable member, and at least one first engaging element disposed on a portion of the shaft. The device for orienting the brachytherapy applicator includes an elongated body defining an open proximal end, an open distal end, and an open channel between the proximal and distal ends adapted for slidably receiving at least a portion of the flexible shaft. The device may also include a manually engageable gripping element at the proximal end of the elongated body, the gripping element operable to constrict at least a portion of the channel around at least a portion of the flexible shaft to prevent rotational movement between the elongated body and the brachytherapy applicator. Furthermore, the device may include at least one second engaging element adapted for releasably engaging the at least one first engaging element of the brachytherapy applicator. The device and brachytherapy applicator are prevented from rotating relative to each other when the at least one first engaging element of the elongated body engages the at least one second engaging element of the brachytherapy applicator. 
         [0006]    In accordance with another aspect of the invention a method for orienting a brachytherapy applicator with the device described above includes the steps of positioning the elongated body on the shaft and controlling axial or rotational movement of the applicator via the device. This may be accomplished by positioning the device relative to the applicator such that the first and second engaging elements engage one another, thereby preventing rotational movement of the shaft and elongated body relative to each other. Applying a force to the gripping element and constricting at least a portion of the channel around at least a portion of the shaft prevents rotational movement of the shaft and elongated body relative to each other. An operator may then perform one or more of (i) axially moving the orienting device and simultaneously axially moving the brachytherapy device relative to a target tissue area of the treatment cavity and (ii) rotating the orienting device and simultaneously rotating the brachytherapy device relative to a target tissue area of the treatment cavity. 
         [0007]    The invention provides a cost effective and easily operable way to orient a brachytherapy applicator. The device enables 1:1 rotation with reduced shaft twist and helps avoid stick-slip by securing a segment of the applicator shaft against twist and spreading the torque load. Tabs reduce reliance on friction between fingers and device or shaft. Advantageously, the device can be mounted and removed without removing the applicator from the treatment cavity. It is also advantageous that the orienting device is an “external tool” that engages the flexible shaft of the brachytherapy applicator externally about its outer surface as opposed to an “internal tool” which must be inserted down an internal shaft lumen to engage an internal engagement structure. Such an external configuration reduces or eliminates the need to incorporate more costly and complex internal structures within the tight diametrical confines of the applicator, which are required to accommodate an internal orienting device. 
         [0008]    These and other features, aspects, and advantages of the disclosed embodiments will become better understood with regard to the following description, appended claims, and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]      FIG. 1  is an isometric view of a brachytherapy system described in the present disclosure. 
           [0010]      FIG. 2A  is top elevation view of the brachytherapy applicator of the system shown in 
           [0011]      FIG. 1 . 
           [0012]      FIG. 2B  is side elevation view of the brachytherapy applicator of the system shown in  FIG. 1 . 
           [0013]      FIG. 3  is an isometric view of the orienting device of the system shown in  FIG. 1 . 
           [0014]      FIG. 4  is another isometric view of the orienting device of the system shown in  FIG. 1 . 
           [0015]      FIG. 5A  is an isometric view of the system of claim  1  showing the orienting device mounted on the shaft of the applicator but disengaged from the shaft. 
           [0016]      FIG. 5B  is a close-up view of the distal ends of the applicator shaft and orienting device shown in  FIG. 5A   
           [0017]      FIG. 5C  is a partial front end view of the system of claim  1  showing the shaft received within the channel and channel is in its relaxed state. 
           [0018]      FIG. 6A  is an isometric view of the system of claim  1  showing the orienting device mounted on the shaft of the applicator and engaged with the shaft. 
           [0019]      FIG. 6B  is a close up view of the distal ends of the applicator shaft and orienting device shown in  FIG. 6A   
           [0020]      FIG. 6C  is a partial front end view of the system of claim  1  showing the shaft received within the channel and channel is in its constricted state. 
           [0021]      FIG. 7A  is a partial isometric view showing the brachytherapy applicator of the system shown in  FIG. 1  implanted within a treatment cavity. The orienting device is inserted on the shaft and being slid forward to engage the shaft. 
           [0022]      FIG. 7B  is a partial isometric view showing the brachytherapy applicator of the system shown in  FIG. 1  implanted within a treatment cavity. The orienting device is engaged with shaft so that the applicator and orienting device may rotate and translate in unison. 
       
    
    
       [0023]    Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present invention. The exemplification set out herein illustrates certain embodiments of the invention, in one, or more forms, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
       DETAILED DESCRIPTION 
       [0024]    Referring to  FIG. 1 , a brachytherapy system is indicated generally by the reference numeral  10 . The system  10  includes a brachytherapy applicator  20 , such as the brachytherapy applicator described in U.S. Patent Application Publication No. 2010/0204534, entitled “Flexible Multi-Lumen Brachytherapy Device”, which is hereby in incorporated by reference in its entirety as part of the present disclosure, and a device adapted for orienting a brachytherapy applicator  50  (hereinafter referred to as the “orienting device”) 
         [0025]      FIGS. 2A and 2B  are top and side elevation views of an embodiment of the brachytherapy applicator  20  which may be used in the system  10  ( FIG. 1 ). The applicator  20  comprises a flexible shaft  22  or catheter body defining a proximal end  24 , a distal end  26  and a shaft lumen  28  extending between the proximal end distal ends. A proximal hub  30  is disposed circumferentially about the proximal end of the shaft and a distal hub  32  is disposed circumferentially about the distal end of the shaft. An inflatable member  34 , such as a balloon, is disposed about the distal end  26  of the shaft  22 . The applicator further includes a tip member  36 , which may form an outboard portion of the distal end of the shaft  22  or, alternatively, may be indirectly coupled to the shaft  22  in which case the tip member  36  is space distally from the distal end of the shaft. In one embodiment, the inflatable member  34  is located between the proximal hub  30  and the tip member  26 . And in some such embodiments, the inflatable member is located between the distal hub  32  and the tip member  36  as illustrated, for example, in  FIGS. 2A-2B . The applicator has a rotational position indicator mark on the shaft which may be aligned with one of the lumens. 
         [0026]    The applicator  20  further includes a flexible inflation lumen  38 , which channels fluid into and out of the inflatable member  34  to inflate and deflate the inflatable member as required. When inflated, inflatable member  34  helps to maintain the position of the applicator  20  with respect to a treatment cavity (see e.g.  FIG. 7A ) into which the applicator was implanted. At least one flexible dosing lumen  40   a  extends through the shaft lumen  28  and into the inflatable member  34 . The dosing lumen  40   a  providing a conduit sized to accommodate and position one or more radiation sources, such as a radioactive seed. In one embodiment, the applicator  20  includes at least four dosing lumens  40   a - d . To help secure the dosing lumens, a positioning hub  46  affixed within the inflatable member  34  between the tip member  26  and distal hub  3234  may be included. The positioning hub defines grooves or channels into which corresponding lumens are secured to maintain their position inside the inflatable member relative to the central longitudinal axis L of the applicator  20 . 
         [0027]    The applicator  20  further includes at least one engaging member  42  (see e.g.  FIGS. 2B and 5B ). In one embodiment, the at least one engaging member is a set of protrusions  44 . The protrusions  44  extend outward from the distal hub  32  and are spaced approximately 180 degrees apart relative to the central longitudinal axis of the applicator  20 . It should be noted however that the protrusions  44  could extend from other locations along the shaft  22  and the angular relationship between the protrusions  44  about the longitudinal axis may be more or less than 180 degrees, as long as the protrusions  44  are able to align with corresponding slots  72  (described below) on the orienting device  50 . 
         [0028]    Referring now to  FIGS. 3 and 4 , an embodiment of the orienting device  50  which may be used in the system  10  ( FIG. 1 ) will be described in further detail. The device  50  comprises an elongated body  52  defining an open proximal end  54 , an open distal end  56 , and an open channel  58  extending longitudinally between the proximal and distal ends. The channel  58  is adapted for slidably receiving at least a portion of the shaft or catheter body of a brachytherapy applicator, such as the flexible shaft  22  of the above-described brachytherapy applicator  20  depicted in  FIGS. 2A-B . The channel defines an outer surface  60  and an inner surface  62 . In one embodiment, the channel  58  is approximately semi-cylindrical or u-shaped; however, the channel  58  may take on other shapes suitable for accommodating the particular shaft or catheter body of a brachytherapy applicator. 
         [0029]    The device  50  includes one or more features which enable a physician to control movement of the brachytherapy applicator. For example, the device may be used to control axial, rotational, or both axial and rotational movement of the applicator  20 . The features may include a mechanism which secures the device  50  to the applicator  20  such that the applicator moves in response to movement of the device  50 . Independent control may be provided such that axial control is disabled while the applicator is rotationally positioned. Operation of the mechanism may be reversible such that the device  50  may be disengaged from the applicator  20 , e.g., after the applicator has been properly positioned. The device may also be used multiple times to reposition the applicator by repeatedly engaging and disengaging the device and applicator. 
         [0030]    In the illustrated embodiment the channel  58  is capable of gripping or otherwise frictionally engaging an inserted shaft or catheter body, such as the shaft  22  of the above-described brachytherapy applicator  20 . In such instances the channel  58  defines a relaxed state and a constricted state. When in the relaxed state, the inner surface  52  of the channel does not frictionally engage the inserted shaft  22  so that the elongated body  52  may slide axially in at least one direction relative to the shaft  22 . When in the constricted state, at least a portion of an inner surface  62  of the channel frictionally engages at least a portion of an outer surface of an inserted shaft  22  so that the elongated body  52  is not axially or rotationally slidable relative to the shaft  22 . 
         [0031]    A manually engageable gripping element  64  provides an actuator operable to transition or otherwise move the channel between the relaxed and constricted states. The manually engageable gripping element  64  resides at or about the proximal end  54  of the elongated body  52 . The gripping element  64  may form a portion or appendage of the elongated body (i.e. the gripping element  64  and elongated body  52  may be a single piece), or the gripping element  64  may be a separate component attached to the elongated member  52 . As noted above, the gripping element  64  is operable to transition or otherwise move the channel between the relaxed and constricted states. In one embodiment, the gripping element  64  includes a pair of opposing tabs or surfaces  66 ,  68  adapted to move or otherwise flex or bend toward each upon application of a lateral force on each tab. The forces are directed inward in a squeezing type motion applied by the operator to substantially simultaneously transition the channel  58  from its relaxed state to its constricted state. Releasing the gripping element (i.e. ceasing the application of the lateral forces on the tabs) will return the channel  28  to its relaxed state; hence, the channel is biased in its relaxed state. 
         [0032]    Referring now to  FIGS. 3 ,  5 A-B and  6 A-B, in the illustrated embodiment the orienting device  50  further includes at least one engaging element  70  located about the distal end  56  of the elongated body and adapted for releasably engaging the at least one (corresponding) engaging element  42  on the brachytherapy applicator  20 . When the at least one engaging element  70  of the elongated body engages the at least one corresponding engaging element  42  of the brachytherapy applicator (or vice versa), the orienting device  50  and brachytherapy applicator  20  are prevented from rotating relative to each other (i.e. the device  50  and applicator  20  can only rotate in unison). In one embodiment, the at least one engaging element  70  is at least one slot  72  defined by a portion of the distal end  56  of the elongated member  52 . The at least one slot  72  is adapted for receiving a corresponding protrusion  44  extending from a portion of the brachytherapy applicator  20 . In the illustrated embodiment, the at least one engaging element includes two slots  72  angularly spaced approximately 180 degrees relative to each other about a central longitudinal axis of the elongated body  52 . It should be noted that the slots  72  could reside at other locations about the elongated member and the angular relationship between the slots  72  about the longitudinal axis may be more or less than 180 degrees, as long as the slots  72  are able to align with their corresponding protrusions  44 . 
         [0033]    The orienting device  50  described above may be made from a polymer such as polypropylene, fluorinated ethylene propylene (FEP), nylon or polyethylene block amide (PEBA). However, as one skilled in the art would recognize, the device  50  may be made from a number of suitable materials including, but not limited to, additional polymers, metals and combinations thereof. 
         [0034]    Having thus described the system  10  and its primary components, an example method of use will now be described. With the brachytherapy applicator  20  having been surgically implanted into a treatment cavity, such as a resected breast lumpectomy cavity  80  shown in  FIGS. 7A-B , the orienting device  50  is inserted onto the shaft  22  of the applicator  20 . When properly inserted, the shaft  22  will rest in the channel  58  of the device  10  and the channel will be in its relaxed state ( FIG. 5C ), allowing the elongated body  52  of the device to slide axially on the shaft  22 . The physician (or operator) then positions the elongated body  52  on the shaft  22  so that the engaging elements  42 ,  70  on the shaft and elongated body align and then engage one another. In the illustrated embodiment, the protrusions  44  on the distal hub  32  of the applicator  20  and the corresponding slots  72  in the distal end  56  of the elongated body  52  of the device  50  form the engaging elements  42 ,  70 . Accordingly, the physician will align the protrusions  42  and slots  70  and (see e.g.  FIGS. 5A-B  and  7 A) and then slide the elongated body  52  distally along the shaft  22  until the protrusions enter and are received by (i.e. engage) the slots (see e.g.  FIGS. 6A-B  and  7 B). When the protrusions are received by the slots, the applicator  20  and orienting device  50  are releasably engaged, thereby preventing rotational movement of the applicator  20  and device  50  relative to each other (i.e. the applicator  20  and device can only rotate in unison; individual rotation of either the applicator  20  or shaft is not permitted). 
         [0035]    As shown in  FIG. 7B , with the engaging members  42 ,  70  engaged the physician then applies a force F to the gripping element  64  to transition the channel  58  of device  50  from its relaxed state ( FIG. 5C ) to its constricted state ( FIG. 6C ) as described above. In the illustrated embodiment, the gripping element  64  comprises a set of tabs  66 ,  68 . Accordingly, the physician will apply a lateral squeezing force to the tabs  66 ,  68 , moving the tabs toward each other and substantially simultaneously transitioning the channel  58  from its relaxed state to its constricted state. In the constricted state, at least a portion of the channel  58  constricts around at least a portion of the shaft  22 , thereby preventing axial and rotational movement of the applicator  20  and orienting device relative to each other. With the applicator  20  and device properly secured, the physician will then perform at least one of the following functions to orient and position the applicator  20  as desired within the treatment  80  and, in particular, orient and position the applicator  20  relative to a target tissue area (not shown) in the treatment cavity. If axial movement is required, the physician will axially move the orienting device  50 , which substantially simultaneously axially moves the brachytherapy applicator  20 . If angular or rotational movement is desired, the physician will rotate the orienting device  50 , which substantially simultaneously rotates the brachytherapy device  20 . It should be noted however that constriction around the distal rigid portion of the shaft resulting from squeezing the proximal tabs may engage the slot features to provide a rigid to rigid connection rather than constricting the whole shaft or flexible portion of the shaft. 
         [0036]    As may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, numerous changes and modifications may be made to the above-described and other embodiments of the present invention without departing from the spirit and scope of the invention as defined and/or described in the specification, drawings and appended claims. It should be understood that the embodiments shown and described and all changes, modifications and equivalents that come within the spirit and scope of the invention are desired to be protected. Accordingly, this disclosure is to be taken in an illustrative, as opposed to a limiting sense. 
         [0037]    All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. Further, regarding the methods and processes described herein, it should be understood that although the steps of such methods and processes have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps (not described) could be added or implied, or that certain steps described herein could be omitted.