Patent Publication Number: US-2011051892-A1

Title: Radiation therapy skin marker

Description:
The invention relates to devices used to delineate radiation therapy portal areas of patients to be treated with radiation. More particularly, the invention relates to markers used to delineate radiation therapy portal areas of patients to be treated with radiation. Even more particularly, the invention relates to a lined markers used to delineate radiation therapy portal areas of patients to be treated with radiation. 
     BACKGROUND OF THE INVENTION 
     Radiation therapy is a common method in the treatment of those individuals diagnosed with cancer. Radiation therapy is used to treat cancer patients in two ways: for curative purposes and for palliative reasons. 
     Virtually all radiation therapy centers are equipped with simulators, which includes a fluoroscopic imaging unit equipped with all the characteristics and parameters found on the radiation treatment units. With the help of diagnostic imaging such as computerized x-ray tomography (CT) and magnetic resonance imaging (MRI), when combined with the fluoroscopic capability of the simulator, a radiation therapy portal, which is the area through that the treating radiation will be focused, may be designed. 
     Markings, also sometimes referred to as tattoos, are typically applied to the skin of a patient in preparation for radiation therapy or other medical treatment, as a means of clearly delineating the location of treatment set-up points. Traditionally, the marking is done by applying a drop of marking agent to the surface of the patient&#39;s skin and then penetrating the skin with a needle to allow the marking agent to flow under the surface of the skin. The size of the needle used can vary widely, some technicians preferring to work with a larger needle, others with a smaller needle. When marking the skin in this way, it is critical that the marking agent, such as India ink, as well as the needle tip be sterile. Furthermore, it is highly desirable to have a disposable needle, to eliminate the possibility of passing pathogens from one person to another and to eliminate the need for sterilizing the needles. It is also desirable to have a marking device that will accept a standard needle that is typically kept in stock in a healthcare facility, in a range of needle gauges. 
     The time between simulation and beginning treatment is usually zero to seven days. During this period, generally greater than one day, various types of markings may be lost. For this reason, tattooing is often used to establish the portal boundaries with some permanency and reproducibility. However, there are several disadvantages to tattooing, even though it may seem to be the most optimal means to establish portal boundaries. 
     One problem is that tattoos are difficult to recognize on dark skin. Thus, tattoos too may not be completely visible during the radiation therapy treatment. 
     An additional problem is that the tattooing process punctures the patient&#39;s skin multiple times and, therefore, has the potential to expose radiation therapy personnel to the patient&#39;s blood and the patient&#39;s blood to out-side contaminants. This exposure creates a risk that the radiation therapy personnel or the patient may be contaminated with various infectious organisms transmitted by blood exposure. 
     Two further problems are associated with the permanency of tattoos. First, a radiation therapy portal boundary tattoo is aesthetically unattractive. This is especially problematic when the tattoo is placed on skin surfaces which are not ordinarily covered by clothing. Second, but technically of equal importance, a radiation therapy portal boundary tattoo is inflexible. Initially, this may seem to be a benefit because it limits the risk that the portal boundary markings might inadvertently shift. However, a portal field for a particular patient is frequently changed throughout the course of treatment thereby requiring a shift in the portal boundary markings. Once tattooing marks are established a re-tattooing is required to shift the portal boundaries thereby compounding the above described disadvantages. 
     Notwithstanding the state of the art as described herein, there is a need for further improvements in transparent radiation therapy skin markers, which facilitate the precise application of the markers for radiation therapy treatment. 
     SUMMARY OF THE INVENTION 
     In order to overcome shortcomings of techniques used to depict portal fields, a specially designed device is presented. This device is easy to apply to the skin of a patient. The device is reliable in that it may retain its original position from about seven and to about ten days. Yet, it may be repositioned easily without risk to patient or personnel. Furthermore, it is removable without leaving any permanent traces on the patient&#39;s skin. 
     The device comprises flat, adhesive-coated marker structures in various shapes which are used to denote the perimeter, isocenter(s), and set-up points of radiation treatment portals on the skin of patients undergoing radiation therapy. In one embodiment, the device includes pieces shaped such that they may be used to delineate the corners, edges connecting the corners, the isocenter point(s), and any set-up points of the proposed radiation field. 
     In general, one aspect of the invention is to provide a device for marking skin surfaces to delineate a radiation therapy portal area. The device includes a substrate comprising a first and second surface, wherein the first surface is lined with an ink to facilitate outlining of a radiation therapy treatment field, an adhesive layer coated onto the second surface of the substrate, and a removable release liner in contact with the adhesive layer. 
     Another aspect of the invention is to provide a method of marking a skin surface to delineate a radiation therapy portal area. The method includes the steps of providing at least one skin marker, removing a portion of a backing liner of a skin marker to expose an adhesive surface of the skin marker, positioning the at least one skin marker on a skin surface of a patient, wherein the positioning of the at least one skin marker delineates a radiation therapy portal area, and releasably securing the at least one skin marker in place on the skin surface of the patient. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a cross-sectional view of a radiation therapy skin marker according to an embodiment of the invention; 
         FIG. 2  illustrates a bottom view of a radiation therapy skin marker according to an embodiment of the invention; 
         FIG. 3  illustrates a perspective view of an arrangement of radiation therapy skin markers for radiation treatment according to an embodiment of the invention; 
         FIG. 4  illustrates a line marker according to an embodiment of the invention; 
         FIG. 5  illustrates one embodiment of an isocenter marker according to an embodiment of the invention; and 
         FIG. 6  illustrates another embodiment of an isocenter marker according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An embodiment of the invention relates to radiation therapy skin markers to delineate radiation therapy portal areas of a patient to be treated with radiation. As seen in  FIGS. 1 and 2 , a radiation therapy skin marker  10  comprises a substrate  12  having a first surface  19  and a second surface (not shown). Surface  19  of substrate  12  is lined with an ink to facilitate the outlining of the treatment field. The second surface is coated with an adhesive layer  14  which is protected by release liner  15 , optionally divided into multiple segments, shown here as  16  and  18 . 
     Substrate  12  of radiation therapy skin marker  10  is prepared from material that is both conformable to the contours of the body, and flexible so as to permit free movement of the body part wearing the product. Further, substrate  12  is lightweight, and is elastic in character. In an embodiment of the invention, substrate  12  is a non-woven substrate, such as a film having a thickness in the range from about 1 mil to about 3 mils. Substrate  12  may be prepared into films from materials including polyolefins, such as polyethylene, polyurethanes, and polyvinylchloride. 
     Adhesive layer  14  of radiation therapy skin marker  10  may be a medical grade adhesive. In one embodiment of the invention, the medical grade adhesive is a pressure sensitive adhesive. An “adhesive” as used herein means any natural or synthetic substance that is capable of surface attachment. As used herein, the term “pressure-sensitive adhesive” refers to a viscoelastic material which adheres instantaneously to most substrates with the application of very slight pressure and remains permanently tacky. Other conventional components may be added to the pressure sensitive adhesive including, but not limited to, inhibitors, fillers, pigments, stabilizers, tackifiers, UV absorbers, and the like. 
     The pressure sensitive adhesive of adhesive layer  14  may include mixtures of different polymers and mixtures of polymers, such as polyisobutylenes (PIB) of different molecular weights. The pressure sensitive adhesive may also be an acrylate or methacrylate based pressure sensitive adhesive. The adhesive is prepared according to standard industry procedures. 
     When the pressure sensitive adhesive is an acrylate or methacrylate based pressure sensitive adhesive, adhesive may be formed by a polymerization reaction product of at least two alkyl acrylate or methacrylate ester monomers, at least one ethylenically unsaturated carboxylic acid, at least one vinyl lactam, and most preferably including a crosslinking agent. Examples of suitable alkyl acrylate or methacrylate esters include, but are not limited to, butyl acrylate, ethyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isodecyl acrylate, methyl acrylate, methylbutyl acrylate, 4-methyl-2-pentyl acrylate, sec-butyl acrylate, ethyl methacrylate, isodecyl methacrylate, methyl methacrylate, and the like, and mixtures thereof. 
     Examples of suitable ethylenically unsaturated carboxylic acids include, but are not limited to, acrylic acid, methacrylic acid, fumaric acid, itaconic acid, and the like, and mixtures thereof. In one embodiment, the ethylenically unsaturated carboxylic acid monomer is acrylic acid. 
     In one embodiment of the invention, the ink used for the line on surface  19  of substrate  12  includes a phosphorescent ink, a fluorescent ink, a dye-based ink, a pigment-based ink, and combinations thereof. In one embodiment, the color of the ink may be blue, red, green, white, black or combinations thereof. The ink may be applied to surface  19  of substrate  12  by a variety of printing and imaging methods including, but not limited to, flexography, lithography, rotogravure, screen printing, digital printing process or combinations thereof. The ink line on surface  19  of substrate  12  is highly visible, which facilitates the application of the radiation therapy skin marker  10  on a desired body surface location of a patient. The colored ink line is also useful for application of the radiation therapy skin marker  10  on a variety of patient skin colors. 
     Radiation therapy skin marker  10  is a skin-contact marker for which its conformability to the contours of the body and flexibility with body movement characteristics are most advantageous. The marker  10  is compatible with human skin, even during extended contact, and is both flexible and conformable. Adhesive layer  14  of radiation therapy skin marker  10  may exhibit sufficient adhesion, or bonding strength, to prevent peeling of the adhesive product from the skin prematurely, but is not tenacious as to damage or irritate the skin during removal, especially sensitive skin, or to leave adhesive residue on the skin. In one embodiment, marker  10  is designed to remain in a designated position on the skin of a patient for at least 7 to about 10 days. Suitable materials that may be used in the preparation of radiation therapy skin marker  10  include DM-8010 and DM-8014 which are manufactured by DermaMed Coatings Company, LLC. 
     In another embodiment of the invention, the radiation therapy skin marker, including substrate  12  and adhesive layer  14 , is clear and transparent. In yet another embodiment of the invention, the radiation therapy skin marker, including substrate  12 , adhesive layer  14 , and release liner  15 , is clear and transparent. In still yet another embodiment of the invention, at least a portion of the radiation therapy skin marker  10  is clear and transparent, thus forming a “zone of transparency”. The transparency of marker  10  facilitates precise application of marker  10  for radiation therapy treatment. 
     In one embodiment, radiation therapy skin marker  10  may be made by coating a layer of the pressure sensitive adhesive onto a liner, and then transferring (laminating) the adhesive onto substrate  12 . The liner, such as a kraft paper, may be coated on one side with a release layer, such as a silicone compound, and is then coated in a first stage, with the adhesive on top of the release layer. The adhesive can be applied to the liner as a solution or emulsion of the adhesive formulation, from which the solvent or water is removed by heating or as a hot melt adhesive such as by casting or extrusion. 
     The substrate  12  may then be laminated to the adhesive layer, in a second stage. If substrate  12  is formed on a carrier, the substrate/carrier laminate is contacted with the adhesive/liner laminate, such that the substrate is interposed between its carrier on one side, and the adhesive layer  14  of the adhesive coated liner on the other side. The carrier is then stripped off of the laminate, and is discarded, thereby leaving a laminate of substrate  12 , adhesive  14  and release liner. 
     Next, the liner is stripped off the laminate. The adhesive sticks to substrate  12 , but not the liner. Simultaneously, a lightweight paper liner coated with a silicone material, which is slit to form release liner segments  16  and  18 , is contacted with the laminate, and then the final laminate is passed to a cutter, or a die, to cut marker  10  to a desired length. 
     In one embodiment of the invention, the radiation therapy skin marker  10  may be provided in either roll form, strips or in sets of pre-cut lengths. A suitable dispenser for a roll of skin markers  10  may be used to dispense a desired length of skin marker  10 . Such dispensers may separate release liner segments  16  and  18  from skin marker  10  prior to use. Packaging for a strip form or the set of pre-cut lengths of skin marker  10  may be provided in sterile, hermetically sealed packages for individual use. 
     Examples of suitable radiation therapy skin markers  10  include a line marker  20  and an isocenter marker  22 . The line markers  20  can be used, respectively, to mark the corners and edges of a square or rectangle radiation therapy portal, as shown in  FIG. 3 . The isocenter markers  22  can be used, respectively, to mark any isocenter and set-up points necessary to a particular radiation therapy treatment, as shown in  FIG. 3 . 
     In one embodiment of the invention, as shown in  FIG. 4 , line marker  20  is somewhat rectangular in shape and defined by short edges  24   a  and  24   b  and long edges  26   a  and  26   b . The long edges  26   a  and  26   b  are multiple times the length of the short edges  24   a  and  24   b . Each line marker  20  includes a printed line  28  extending between the short edges  24   a  and  24   b  and parallel to the long edges  26   a  and  26   b . The line markers  20  may placed by a radiation therapist such that the printed lines  28  of each line marker  20  outline the edges of a specified square or rectangular radiation therapy portal (as shown in  FIG. 5 ). The printed lines  28  assist in creating a discernable target for a radiation therapist performing radiation therapy treatments. 
     In another embodiment of the invention, as shown in  FIG. 5 , isocenter marker  22  is circularly shaped and is defined by a circular outer edge  30  and a midpoint  32 . Each isocenter marker  22  includes four printed lines  34   a - 34   d  extending radially from the midpoint  32  to the circular outer edge  30 . The printed lines  34   a - 34   d  are further defined in that they intersect at midpoint  32  in such a way that lines  34   a  and  34   c  would each be perpendicular to lines  34   b  and  34   d . In an alternative embodiment, as seen in  FIG. 6 , each isocenter marker  22  includes at least two printed lines  36  and  38  that intersect to form midpoint  32 . Line  36  extends from one point ( 36   a ) on circular outer edge  30  to another point ( 36   b ) on the circular edge  30 . Line  38  extends from one point ( 38   a ) on circular outer edge  30  to another point ( 38   b ) on the circular edge  30 . The printed lines  36  and  38  are further defined in that they intersect at midpoint  32  in such a way that line  36  is perpendicular to line  38 . The isocenter markers  22  may be placed by a radiation therapist such that the printed lines  34   a - 34   d , as well as lines  36  and  38 , define an isocenter of a specific radiation therapy portal as the point where the lines  34   a - 34   d , as well as lines  36  and  38 , would intersect thereby assisting a radiation therapist perform radiation therapy treatments, as seen in  FIG. 3 . 
     Based upon the foregoing disclosure, it should now be apparent that the radiation therapy skin markers as described herein will carry out the objects set forth hereinabove. It is, therefore, to be understood that any variations evident fall within the scope of the claimed invention and thus, the selection of specific component elements can be determined without departing from the spirit of the invention herein disclosed and described.