Abstract:
A comfortable, light weight device to properly position and elongate breast tissue for extended periods of time during radiotherapy and other medical procedures. In one embodiment, the breast fixation device is a generally cylindrical inflatable enclosure that wraps around the breast tissue. In another embodiment, the breast fixation device is composed of multiple rings that are placed around the breast tissue and inflated. In a further embodiment, the breast fixation device consists of multiple inflatable fingers which drape around the breast tissue and then squeeze the breast tissue into an elongated position as they are inflated.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a national phase of PCT application PCT/US13/68755, filed on Nov. 6, 2013, under 35 U.S.C. §371 and claims benefit of U.S. provisional application 61/724,240, filed Nov. 8, 2012, the disclosure of which is hereby incorporated herein in its entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to devices for advantageously supporting women&#39;s breasts during breast cancer radiotherapy and other medical procedures. More specifically, inflatable, lightweight, easy-to-use devices are provided to elongate and immobilize breast tissue. 
       BACKGROUND OF THE INVENTION 
       [0003]    In 2011, an estimated 230,480 new cases of invasive breast cancer were expected to be diagnosed in the U.S. and 39,520 women were expected to die from the disease. The standard care for these patients is surgery followed by radiotherapy, which has been shown to significantly decrease the risk of loco-regional tumor recurrence. 
         [0004]    Modern radiotherapy is known for its extremely high geometrical accuracy targeting at the tumors. For most cancers treated by radiotherapy, an accuracy of 3 mm is achieved. However, the accuracy of breast treatment is an order of magnitude worse due to poor set up and immobilization techniques. Breast setup and immobilization have been a persistent problem. The challenge can be appreciated from  FIGS. 1A and 4A  showing breast tissue when a patient is set up in the supine position without any form of breast support. The breast tissue is naturally pulled towards the patient chest by gravity. In order to treat the breast using a whole breast irradiation technique, the radiation field has to cover the entire volume marked by the intersecting line, including part of the heart and the lung. The over inclusiveness of the radiated tissue could lead to severe long term side effects. For example, the skin fold, where the pendulous breast is in contact with the chest skin, will receive a full dose from the radiation treatment, resulting in painful skin erythema and long term side effects as shown in  FIG. 2A . Due to the uncertainty in the breast shape and position, a large geometrical margin has to be used that leads to increased normal breast tissue dose in partial breast irradiation method. This additional margin requirement necessitates treatment of larger volumes of normal breast tissue and recent reports have suggested that external beam partial breast irradiation may be associated with increased toxicity, specifically subcutaneous fibrosis and suboptimal cosmetic outcome ( FIG. 2B ). 
         [0005]    In  FIGS. 1B and 4B , a breast is shown in the prone position without any form of breast support. Radiotherapy in the prone position can improve the radiation dosimetry. The advantages are obvious that, due to the greater distance between the breast and patient body and the disappearance of mammary skin fold, lower toxicities to normal organs other than the breast are achievable. On the other hand, the prone position cannot be tolerated by many patients for repeating daily treatment. Also, the setup time is longer and the setup uncertainties are greater than treatments in the supine position. Furthermore, lymph nodes cannot be easily treated in this prone position. Due to these reasons, most patients will still be treated in the supine position that is associated with poor treatment accuracy and higher risk of severe toxicity. 
         [0006]    A number of devices have been proposed to assist breast set up in the supine position. These devices include the breast thermoplastic cast shown in  FIG. 3A . For this thermoplastic cast, the thermoplastic material is firm at room temperature but becomes moldable when heated up to 60° C. It can be then used to create masks that conform to patient breast contour. Thermoplastic masks are widely used in the immobilization of head and neck patients where sufficient bony structures can be immobilized by the mask. Its application in breast immobilization, though, has been unsuccessful due to the lack of rigidity in the breast tissue. It also increases radiation skin dose and leads to more severe skin reactions. A vendor has recently removed the thermoplastic cast product from their catalog. 
         [0007]    A second type of existing breast support device for use in the supine position is the breast ring shown in  FIG. 3B . The breast ring device consists of a reinforced polyvinylchloride tube formed into a ring that is placed around the breast. A strap around the patient&#39;s chest holds the ring in place. The breast ring provides very limited improvement in the breast position, though, at a cost of significantly higher skin dose at areas in contact with the ring. The breast ring idea was first published in 1994, but has never found much clinical acceptance. 
         [0008]    A third type of existing breast support device is a plastic cup with or without vacuum as shown in  FIG. 3C  and described in U.S. Pat. Nos. 8,210,899; 7,742,796 and 7,597,104. Plastic cups with vacuum (i.e., suction cups) were experimented with as breast immobilization devices and found some success when the patient is not in the supine position. Breast tissue with suction cup support is shown in  FIG. 4C . Nonetheless, the shear force applied on the skin would be too high to tolerate when the cups are used to lift the breast against gravity. As a result of these failed attempts, there are currently no viable commercial suction cup products. Typically, patients are either treated these days without any breast set up and immobilization device, or with improvised methods such as bubble wraps, tapes or straps that result in very poor positioning accuracy. 
         [0009]    Other prior art efforts at breast immobilization are described in U.S. Pat. Nos. 6,418,188; 7,828,744; 7,489,761 and 6,146,377. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The present invention provides a comfortable, light weight device to properly position breast tissue for extended periods of time during radiotherapy and other medical procedures, particularly when the patient is in the supine position. In its preferred embodiments, the breast fixation device of the present invention comprises one or more inflatable cylinders, rings or gripping fingers that wrap around the surface of the breast tissue. The breast fixation device is preferably formed from a lightweight polymer, such as medical grade polyethylene. 
         [0011]    In one preferred embodiment, the breast fixation device takes the form of an airtight, inflatable polymeric enclosure having generally cylindrical interior and exterior walls. A hollow, generally cylindrical shaped interior cavity defined by the interior walls of the enclosure surrounds the breast tissue. To help maintain the generally cylindrical shape and provide the necessary breast support, the breast fixation device is preferably formed from a plurality of longitudinal sections. 
         [0012]    In a first alternative embodiment, the breast fixation device consists of a plurality of inflatable concentric rings that are preferably connected together. To most effectively elongate and position the breast, each ring preferably has its own inflation valve so that the rings can be sequentially inflated starting with the ring closest to the patient&#39;s chest and proceeding outward. To achieve an optimal tilt to the breast after it has been elongated, one of the inflatable rings can be divided into sections having separate valves. By inflating some of the sections of this ring, but not others, the breast can be tilted to the desired orientation. 
         [0013]    In a second alternative embodiment, the breast fixation device consists of a plurality of inflatable finger-like grippers. In this embodiment, the finger-like grippers are draped over the breast before being inflated. When the finger-like grippers are then inflated, they grab the surface of the breast and elongate the breast upward. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1A  shows breast tissue when a patient is set up in the supine position without any form of breast support. 
           [0015]      FIG. 1B  shows breast tissue when a patient is set upon in the prone position without any form of breast support. 
           [0016]      FIGS. 2A and 2B  show long term effects of radiation therapy on breasts when the breasts are not properly supported and positioned. 
           [0017]      FIG. 3A  shows a prior art thermoplastic cast. 
           [0018]      FIG. 3B  shows a prior art breast ring. 
           [0019]      FIG. 3C  shows prior art plastic breast cups. 
           [0020]      FIG. 4A  shows a breast in a normal supine position. 
           [0021]      FIG. 4B  shows a breast in a normal prone position. 
           [0022]      FIG. 4C  shows a breast held within a plastic suction cup. 
           [0023]      FIG. 5A  shows a perspective view of a generally cylindrical breast fixation device of the present invention. 
           [0024]      FIG. 5B  shows a cross-sectional view of the generally cylindrical breast fixation device of  FIG. 5A . 
           [0025]      FIG. 6A  shows a cross-sectional view before inflation of a first alternative breast fixation device of the present invention having inflatable rings. 
           [0026]      FIG. 6B  shows the breast fixation device of  FIG. 6A  as the first ring is inflated. 
           [0027]      FIG. 6C  shows the breast fixation device of  FIG. 6A  after the first and second rings are inflated. 
           [0028]      FIG. 6D  shows the breast fixation device of  FIG. 6A  when all the rings are fully inflated. 
           [0029]      FIG. 6E  shows the fully inflated breast fixation device of  FIG. 6D  when the patient has been moved from the prone position to the supine position. 
           [0030]      FIG. 6F  show a perspective view of a breast tilt ring. 
           [0031]      FIG. 6G  shows how inflation of one section of the breast tilt ring of  FIG. 6F , but not of the other sections, can tilt the breast tissue. 
           [0032]      FIG. 7A  shows a front view of a second alternative breast fixation device featuring multiple finger-like grippers. 
           [0033]      FIG. 7B  shows the finger-like gripper embodiment of  FIG. 7A  as the finger-like grippers are being inflated. 
           [0034]      FIG. 7C  shows the finger-like gripper embodiment of  FIG. 7C  when the finger-like grippers are fully inflated. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0035]    Referring now to  FIGS. 5A and 5B , a preferred breast fixation device  10  of the present invention is shown. This breast fixation device  10  is preferably formed of a lightweight polymer, such as medical grade polyethylene, and has a generally cylindrical interior layer  14  as well as a generally cylindrical exterior layer  16 . The thickness of the interior and exterior layers  14 ,  16  is preferably on the order of approximately 0.1 mm to 0.2 mm in order to keep the breast fixation device lightweight, while still providing sufficient strength and durability. The interior  14  and exterior  16  layers of the breast fixation device  10  form both an inflatable enclosure  15  and a hollow interior cavity  13 . 
         [0036]    In operation, the interior layer  14  of the breast fixation device  10  is placed around the patient&#39;s breast  22  before inflation. A pump (not shown), such as an electric or manual pump, is attached to valve  20 , which is preferably a one-way valve. Air  21  is gradually pumped into breast fixation device  10  through valve  20  until the breast fixation device  10  is fully inflated. Preferably, the air fixation device  10  is inflated to a pressure on the order of approximately 12-15 psi. After radiation therapy is completed using one of the breast fixation devices of the present invention, a stem can be inserted into the valve  20  to deflate the breast fixation device or, alternatively, the breast fixation device can be removed by pealing it off the breast  22 . 
         [0037]    The breast fixation device  10  shown in  FIGS. 5A and 5B  has a generally cylindrical shape when full inflated with a hollow, generally cylindrical shaped inner cavity  13 . In the illustrated embodiment, it is formed in a plurality of longitudinal sections  18 . Nonetheless, as recognized by those of skill in the art, it could easily be formed without such sections  18 . When a cylindrical breast fixation device  10  of the type shown in  FIG. 5A  is placed around a flaccid human breast  22  and inflated, it will elongate the breast  22  into a firmer, more stable position as shown in  FIG. 5B  so that the patient will be ready for radiation therapy. Since the breast fixation device  10  of the present invention is lightweight (i.e., similar to a balloon), it can be well tolerated by patients during radiation therapy procedures that often last for an hour or more. 
         [0038]    A first alternative breast fixation device  30  of the present invention is shown in  FIGS. 6A-6G . This breast fixation device  30  features multiple donut-shaped inflatable rings  32 ,  34 ,  36  and, optionally, a donut-shaped inflatable tilting ring  40 . The rings  32 ,  34 ,  36 ,  40  are preferably interconnected with one another to form a hollow generally cylindrically shaped interior cavity  41 . This first alternative breast fixation device  30  embodiment differs from the  FIG. 5A  embodiment by having the inflatable ring sections  32 ,  34 ,  36  positioned horizontally transverse to the breast tissue  22  rather than vertically parallel to the breast tissue  22 . In the preferred embodiment, each inflatable ring  32 ,  34 ,  36  has a separate inflation valve  42 ,  44 ,  46 , respectively. Having separate inflation valves  42 ,  44 ,  46  allows the rings to be inflated sequentially, rather than all at once. Like the  FIG. 5A  embodiment, the first alternative breast fixation device  30  is preferably formed of a lightweight polymer, such as medical grade polyethylene, having a thickness on the order of 0.1 mm to 0.2 mm. 
         [0039]      FIG. 6A  shows the first alternative breast fixation device  30  before any of the rings  32 ,  34 ,  36  have been inflated. To achieve the desired results, the patient is preferably first placed in the prone position so that the breast  22  is hanging downward. The inflatable ring  32  closest to the patient&#39;s chest is preferably inflated first, as shown in  FIG. 6B . By inflating the ring  32  closest to the patient&#39;s chest first, the breast tissue  22  is urged into a more elongated, downward position. As shown in  FIG. 6C , the adjacent ring  34  moving away from the patient&#39;s chest is inflated next. The ring  36  furthest away from the patient&#39;s chest is preferably inflated last, as shown in  FIG. 6D . When all three rings  32 ,  34 ,  36  have been inflated as shown in  FIG. 6D , the patient&#39;s breast is suitably immobilized for radiation therapy. As shown in  FIG. 6E , the patient is then preferably moved from the prone position to the supine position to conduct the radiation therapy. Because of the breast fixation device  30  of the present invention, the breast  22  remains in an elongated, immobilized position even when the patient is moved from a prone position to a supine position. While the first alternative breast fixation device  30  is shown here with three inflation rings  32 ,  34 ,  36 , those of skill in the art will recognize that a greater or lesser number of rings could also be used. Also, while separate valves  42 ,  44 ,  46  are shown in the illustrated embodiment to allow for sequential inflation of the rings  32 ,  34 ,  36 , those of skill in the art will recognize that fewer or greater numbers of valves could also be used and still accomplish an elongated fixation of the breast tissue. 
         [0040]    In addition to the inflatable rings  32 ,  34 ,  36 , the first alternative breast fixation device also preferably includes a tilting ring  50 . When the breast is immobilized by the inflatable rings  32 ,  34 ,  36 , it may need to be tilted at a particular angle to achieve the best results during radiotherapy. The tilting ring  50  allows this tilting to occur. A close-up view of the tilting ring is shown in  FIGS. 6F and 6G . In the preferred embodiment, the tilting ring  50  has three separately inflatable sections  52 ,  54 ,  56 , each with its own inflation valve  53 ,  55 ,  57 . As shown in  FIG. 6G , when one of the tilting ring sections  52  is inflated, it will press against the breast  22  and tend to tilt it. 
         [0041]    A second alternative breast fixation device  60  embodiment is shown in  FIGS. 7A-7C . This breast fixation device  60  has a plurality of gripping fingers  62 ,  64 ,  66 ,  68  which can be draped on top of the breast as shown in  FIG. 7A . In the illustrative embodiment, four gripping fingers  62 ,  64 ,  66 ,  68  are shown. Nonetheless, those of skill in the art will recognize that a different number of gripping fingers could be used, preferably ranging from four to ten gripping fingers. Each gripping finger  62 ,  64 ,  66 ,  68  preferably consists of an inflatable stem  63  and multiple bulbs  61  on the side of the stem  63  facing away from the breast  22 . The stem  63  and bulbs  61  are preferably formed as an integral unit so that they can be inflated together. Moreover, the gripping fingers  62 ,  64 ,  66 ,  68  preferably have a common inflation valve  69  so that, when they are inflated, they are inflated simultaneously. As with the other breast fixation device embodiments  10 ,  30 , the second alternative breast fixation device  60  is preferably formed from a lightweight polymer, such as medical grade polyethylene, having a thickness on the order of 0.1 mm to 0.2 mm.  FIGS. 7B and 7C  illustrates how the gripping finger breast fixation device  60  attaches to the patient&#39;s breast  22  and elongates it during inflation. Specifically, as the gripping finger bulbs  61  are inflated, they press against each other and cause the gripping fingers  62 ,  64 ,  66 ,  68  to curl around the breast  22  and thereby elongate the breast tissue upward. Since, in the preferred embodiment, all of the gripping fingers  62 ,  64 ,  66 ,  68  are inflated simultaneously through a single valve  69 , the gripping fingers  62 ,  64 ,  66 ,  68  curl around the breast  22  symmetrically and at the same rate. This second alternative breast fixation device embodiment  60  has the advantage of allowing the patient to remain in the same position, such as the supine position, while the breast is being immobilized without the need to change to a different position. Preferably, the breast fixation device  60  is tethered by tube  71  to a vertically movable fixture  72  ( FIG. 7A ) so that the breast can be lifted after it is immobilized. 
         [0042]    In the foregoing specification, the invention has been described with reference to specific preferred embodiments and methods. It will, however, be evident to those of skill in the art that various modifications and changes may be made without departing from the broader spirit and scope of the invention as set forth in the appended claims. For example, a strap may be used with one or more of the breast fixation devices of the present invention to better attach it to a patient&#39;s body. The specification and drawings are, accordingly, to be regarded in an illustrative, rather than restrictive sense.