Patent Publication Number: US-2013236857-A1

Title: Cavitation Medication Delivery System

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/US2012/058340, filed Oct. 1, 2012, which claims priority of U.S. Provisional Patent Application No. 61/541,029, filed Sep. 29, 2011, each of which is herein incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The technology described herein relates generally to the delivery of a substance to a target region and more particularly to the use of electromagnetic radiation emitting devices for delivering a substance to a target region via a vapor bubble. 
     BACKGROUND 
     A primary cause of infection, disease, and death in humans is inadequate bacteria control. Thus, killing or removing bacteria from various systems of the human body is an important part of many medical and dental procedures. For example, during a root canal procedure, the root canal is disinfected by mechanical debridement of the canal wall and an application of an antiseptic substance within the canal to kill remaining bacteria. However, dental technology has found it difficult to completely eradicate all bacteria during a root canal procedure. In particular, the structural anatomy of the tooth makes it difficult to eliminate all bacteria because the root canal includes irregular canals and microscopic tubules where bacteria can lodge and fester. Bacteria control in other medical and dental procedures has proven equally difficult, and the failure to control bacteria during these procedures can lead to a variety of health and medical problems (e.g., presence of bacteria in the bloodstream, infection of organs including the heart, lung, kidneys, and spleen). 
     SUMMARY 
     Systems and methods are provided for delivering a substance to a target region in a vapor form. In a method for delivering a substance to a target region in a vapor form, a fluid is placed within an interaction zone, where the interaction zone is a volume that extends into the target region or that is adjacent to the target region. An electromagnetic radiation emitting fiber optic tip is positioned within the interaction zone. The fiber optic tip contains the substance that is transparent to a first wavelength of energy and that substantially absorbs a second wavelength of energy. A vapor bubble is created within the interaction zone by exposing the fluid to electromagnetic radiation at the first wavelength, where the electromagnetic radiation at the first wavelength is substantially absorbed by the fluid in the interaction zone. The substance is released in a vapor form into the vapor bubble by exposing the substance to electromagnetic radiation at the second wavelength. The electromagnetic radiation at the first and second wavelengths are emitted by the fiber optic tip. 
     A system for delivering a substance to a target region in a vapor form includes a fluid, where the fluid is located within an interaction zone that is a volume extending into the target region or adjacent to the target region. The system also includes an electromagnetic radiation emitting fiber optic tip. The fiber optic tip is positioned within the interaction zone and contains the substance that is transparent to a first wavelength of energy and that substantially absorbs a second wavelength of energy. The system further includes an electromagnetic energy source. The electromagnetic energy source is configured to generate electromagnetic radiation at the first and second wavelengths for emission by the fiber optic tip. The emitted electromagnetic radiation at the first wavelength is substantially absorbed by the fluid and is configured to create a vapor bubble within the fluid. The emitted electromagnetic radiation at the second wavelength is configured to release the substance in a vapor form into the vapor bubble. 
     In another method for delivering a substance to a target region in a vapor form, a fluid is placed within an interaction zone. The interaction zone is a volume that extends into the target region or that is adjacent to the target region. An electromagnetic radiation emitting element is positioned within the interaction zone, where the element contains the substance that is transparent to a particular wavelength of energy. A vapor bubble is created within the fluid by exposing the fluid to electromagnetic radiation at the particular wavelength. The electromagnetic radiation at the particular wavelength is emitted by the electromagnetic radiation emitting element and is substantially absorbed by the fluid in the interaction zone. During the creation of the vapor bubble, the substance is released into the vapor bubble. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIGS. 1A ,  1 B,  1 C, and  1 D depict an example system for delivering a substance to a target region in a vapor form. 
         FIG. 2  depicts a block diagram of an example system utilizing a dual-wavelength electromagnetic energy source and a multi-mode fiber optic cable to deliver a substance to a target region in a vapor form. 
         FIG. 3  depicts example timing diagrams illustrating aspects of a method for delivering a substance to a target region in a vapor form. 
         FIG. 4  depicts fiber optic cables inserted into root canals of a tooth for intra-canal disinfection, cleaning, and/or medication delivery. 
         FIG. 5  illustrates an example system for delivering a medication or cleaning agent to a target area via a plurality of vapor bubbles carrying the medication or the cleaning agent in a vapor form. 
         FIGS. 6A and 6B  depict example systems that utilize a spraying technique to disperse medication into a vapor bubble for delivery to a target region. 
         FIG. 7  depicts a block diagram of an example system utilizing an electromagnetic energy source with a plurality of laser sources to deliver a medicine to a target region in a vapor form. 
         FIG. 8  is a flowchart illustrating an example method for delivering a substance to a target region in a vapor form. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A ,  1 B,  1 C, and  1 D depict an example system for delivering a substance  108  to a target region  102  in a vapor form.  FIG. 1A  depicts the example system during a first period of time  100 . In  FIG. 1A , a fluid  104  is placed within the target region  102 . The fluid  102  may be, for example, a water-based solution or a saline solution. The target region  102  is a cavity, canal, passage, opening, or surface to which it is desired that the substance  108  be delivered (e.g., a root canal to which it is desired that iodine be delivered to kill bacteria). During the first period of time  100 , in addition to the fluid  104  being placed in the target region  102 , a fiber optic tip  106  is also positioned within the target region  102 . The fiber optic tip  106  is an electromagnetic radiation emitting fiber optic tip and is connected via a multi-mode fiber optic cable to an electromagnetic energy source. The electromagnetic energy source generates electromagnetic radiation that is routed along the multi-mode fiber optic cable and emitted by the fiber optic tip  106 . As illustrated in  FIG. 1A , the fiber optic tip  106  is coated in the substance  108  to be delivered to the target region  102 . The fiber optic tip  106  may be coated in any adequate manner (e.g., via dip-coating and/or various deposition techniques including sputtering and evaporation). The substance  108  coats the fiber optic tip  106  such that electromagnetic radiation of certain wavelengths emitted by the fiber optic tip  106  interacts with the substance  108  as it is emitted from the tip  106 . 
     The fiber optic tip  106  may be of a variety of different shapes (e.g., conical, angled, beveled, double-beveled), sizes, designs (e.g., side-firing, forward-firing), and materials (e.g., glass, sapphire, quartz, hollow waveguide, liquid core, quartz silica, germanium oxide). In one example, the fiber optic tip  106  is made of glass with a diameter of 400 μm, and the substance  108  coating the fiber optic tip  106  is iodine having a coating thickness of 1-2 μm. Further, although the system of  FIGS. 1A ,  1 B,  1 C, and  1 D illustrates the use of the fiber optic tip  106  as the light emitting element of the system, in other examples, various waveguides, light emitting elements (e.g., light emitting nanoparticles and nanostructures, quantum dots), and/or devices including mirrors, lenses, and other optical components may be used in place of the fiber optic tip  106  for light emission. 
     During a second period of time  140 , a vapor bubble  142  is created within the target region  102 . The vapor bubble  142  is created by exposing the fluid  104  to electromagnetic radiation at a first wavelength  144 . The exposing of the fluid  104  is accomplished by focusing or placing a peak concentration of the electromagnetic radiation at the first wavelength  144  on the fluid  104  using the fiber optic tip  106 . The first wavelength  144  is selected to be substantially absorbed by the fluid  104  and transparent to the substance  108 . Thus, the electromagnetic radiation at the first wavelength  144  is generated by the electromagnetic energy source, routed to the fiber optic tip  106  via the multi-mode fiber optic cable, and emitted via the fiber optic tip  106  into the fluid  104 . The electromagnetic radiation at the first wavelength  144  passes through the substance  108  coating the fiber optic tip  106  in a relatively unimpeded manner because of the transparency of the substance  108  to the first wavelength  144 . Due to the high absorption of the first wavelength  144  in the fluid  104 , the vapor bubble  142  forms near the end of the fiber optic tip  106 . 
     As noted above, the fluid  104  substantially absorbs electromagnetic radiation at the first wavelength  144 . In  FIG. 1B , the fluid  104  is a water-based solution, and the first wavelength  144  is within the range of 2.6 μm-3.1 μm, which is substantially absorbed by water. In one example, the electromagnetic radiation at the first wavelength  144  is delivered to the fluid  104  as a pulse of light, rather than as a continuous, steady-state beam of light. In another example, the electromagnetic radiation at the first wavelength  144  has a wavelength of 2.79 μm, a pulse width of 50 μs, a pulse energy of 20 mJ, and a peak power of 400 W. 
     During a third period of time  180 , the substance  108  is released in a vapor form  182  into the vapor bubble  142 . The substance  108  is released in vapor form  182  by exposing the substance  108  to electromagnetic radiation at a second wavelength  184 . The second wavelength  184  is selected to be substantially absorbed by the substance  108 . The electromagnetic radiation at the second wavelength  184  is generated by the electromagnetic energy source, routed to the fiber optic tip  106  via the multi-mode fiber optic cable, emitted via the fiber optic tip  106 , and absorbed within the substance  108  coating the fiber optic tip  106 . The power of any electromagnetic radiation at the second wavelength  184  that reaches the fluid  104  is highly attenuated due to the high absorption of the second wavelength  184  in the substance  108 . The absorption of the electromagnetic radiation at the second wavelength  184  by the substance  108  causes the substance  108  to evaporate into the vapor bubble  142 . Although  FIGS. 1B and 1C  depict the electromagnetic radiation at the first and the second wavelengths  144 ,  184  as being emitted independently of each other, in some systems, the first and second wavelengths  144 ,  184  are pulses of light launched at substantially similar times. In these systems, the substance  108  is released in vapor form  182  into the vapor bubble  142  during a period of time in which the vapor bubble  142  is being created. The vapor bubble  142  containing the substance  108  in vapor form  182  is used to deliver the substance  108  to various parts of the target region  102 . 
     In the system illustrated in  FIG. 1C , the second wavelength  184  is configured to match an absorption peak of the substance  108  and may be within a range of 350 nm-2500 nm, which includes electromagnetic radiation within the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. In an example system, the electromagnetic radiation at the second wavelength  184  is delivered to the substance  108  as a pulse of light, where the electromagnetic radiation at the second wavelength  184  has a wavelength of 940 nm, a pulse width of 1 ms, a pulse energy of 1 mJ, and a peak power of 1 W. 
     In the system  190  illustrated in  FIG. 1D , the tip  106  has five open channels  192 , which are used to incorporate the substance  108  into the vapor bubble  142 . The substance  108  is not coated over the end of the tip  106 , as in the preceding figures. The substance  108  can thus be in the form of the coating over the end of fiber optic tip  106 , or the substance  108  can be impregnated into pores of the tip  106  itself. 
     Although the vapor bubble  142  is described herein primarily as a means of delivering the substance  108  in vapor form  182  to the target region  102 , in some systems, the vapor bubble  142  may itself play a role in achieving disinfection, cleaning, and/or other functions in the target region  102 . As described above, the vapor bubble  142  is created by exposing the fluid  104  to the electromagnetic radiation at the first wavelength  144 . In an example system, an initial pulse of radiation operates to generate the vapor bubble  142 . Following this initial pulse, additional radiation pulses expand the vapor bubble  142  until the pressure on the outside of the vapor bubble  142  reaches a limit, and the bubble collapses, creating shock waves in the fluid  104 . The shock waves can clean and/or disrupt (e.g., remove) substances within the target region  102  (e.g., remove and/or kill bacteria within the target region  102 ). In other systems, the vapor bubble  142  may be engineered to explode rapidly, which can be used to impart strong, concentrated forces on the target region  102  and/or particles within the target region  102 . 
     The target region  102  may be of a small size (e.g., on the order of the size of the fiber optic tip  106 ) and may be a cavity, canal, passage, opening, or surface of the human body (e.g., a root canal passage, tubule of a tooth, tooth cavity, blood vessel). Thus, the system of  FIGS. 1A ,  1 B,  1 C, and  1 D for delivering the substance  108  to the target region  102  may be employed in the context of a variety of medical or dental procedures (e.g., treating tissue, removing deposits and stains from surfaces, removing or killing bacteria). For example, the system of  FIGS. 1A ,  1 B,  1 C, and  1 D may be used as part of a root canal treatment procedure, where the substance  108  is a medicine, cleaning agent, biologically-active particle, antiseptic, or antibiotic, and the target region  102  is a portion of a root canal. The substance  108  is configured to clean, remove bacteria, kill bacteria, disinfect, and/or apply a medical treatment to the root canal. 
     Non-dental applications of the system of  FIGS. 1A ,  1 B,  1 C, and  1 D include procedures within a human body passage, such as a vessel (e.g., blood vessel) or an opening, cavity, or lumen within hard or soft tissue (e.g., treatment of occluded arteries or necrotic bone). Another use of the system of  FIGS. 1A ,  1 B,  1 C, and  1 D is in the treatment of a surface condition of the skin (e.g., skin having an acne condition), where the substance  108  used to treat the surface condition includes an antibacterial agent such as minocycline hydrochloride. Substances that may be delivered to the target region  102  include medications, such as antibiotics, steroids, anesthetics, anti-inflammatory treatments, antiseptics, disinfectants, adrenaline, epinephrine, astringents, vitamins, herbs, and minerals. In one particular system, the substance  108  to be delivered to the target region  102  is iodine, and the iodine is configured to kill bacteria within the fluid  104  and/or on walls of the target region  102 . 
       FIG. 2  depicts a block diagram of an example system  200  utilizing a dual-wavelength electromagnetic energy source  202  and a multi-mode fiber optic cable  204  to deliver a substance to a target region  210  in a vapor form. In the system  200  of  FIG. 2 , the electromagnetic energy source  202  includes sources  202 A and  202 B, which are configured to generate first and second wavelengths λ 1  and λ 2 , respectively. With reference to  FIGS. 1B and 1C , the first wavelength λ 1  is used to create the vapor bubble  142  within the fluid  104 , and the second wavelength λ 2  is used to release the substance  108  in vapor form  182  into the vapor bubble  142 . The electromagnetic energy source  202  is connected to both the multi-mode fiber optic cable  204  and a controller  212 . The multi-mode fiber optic cable  204  routes the electromagnetic energy generated by the first and second sources  202 A,  202 B to a fiber optic tip  201 . The fiber optic tip  201  is connected to an interaction zone  208  (e.g., positioned within the interaction zone  208 ) and delivers electromagnetic radiation to the interaction zone  208 . The interaction zone  208  is a volume of space that extends into the target region  210  or that is adjacent to the target region  210 . Further, with reference to  FIGS. 1B and 1C , the interaction zone  208  includes an area in which electromagnetic radiation emitted from the fiber optic tip  106  and the fluid  104  interact to form the vapor bubble  142 . 
     The interaction zone  208  is also connected to a fluid delivery system  206 , which is configured to supply a fluid to the interaction zone  208 . The fluid delivery system  206  receives the fluid from a fluid source  203 . In one example, the fluid delivery system  206  is configured to fill the volume comprising the interaction zone  208  with the fluid. The interaction zone  208  may be a portion of a cavity, opening, canal, or passage, and the fluid delivery system  206  may be configured to fill the portion of the cavity, opening, canal, or passage with the fluid. In another example, the fluid delivery system  206  is an atomizer used to deliver atomized fluid particles into the interaction zone  208 . In this example, the fluid is supplied as a stream or mist of conditioned fluid particles and may not completely fill the volume of the interaction zone  208 . Further, the controller  212  to which the fluid delivery system  206  is connected may allow a user to specify a size and/or other characteristics of the fluid particles to be supplied to the interaction zone  208 . 
     The fiber optic tip  201  is coated with the substance to be delivered to the target region  210 . The substance is transparent to the first wavelength λ 1  supplied by the first source  202 A and substantially absorbs light at the second wavelength λ 2  supplied by the second source  202 B. In the interaction zone  208 , a vapor bubble is created by exposing the fluid delivered by the fluid delivery system  206  to electromagnetic radiation at the first wavelength λ 1 . The electromagnetic radiation at the first wavelength λ 1  is emitted by the fiber optic tip  201  and is substantially absorbed by the fluid in the interaction zone  208 . During creation of the vapor bubble, the substance to be delivered to the target region  210  is released in vapor form into the vapor bubble by exposing the substance to electromagnetic radiation at the second wavelength λ 2 . The electromagnetic radiation at the second wavelength λ 2  is emitted by the fiber optic tip  201 , which causes it to interact with the substance that coats the fiber optic tip  201 . During this interaction, the electromagnetic radiation at the second wavelength λ 2  is substantially absorbed by the substance, causing it to vaporize into the vapor bubble that is being created. 
     The controller  212  is connected to the electromagnetic energy source  202 , the fluid source  203 , and the fluid delivery system  206 , and is used to synchronize the delivery of the electromagnetic radiation and the fluid to the interaction zone  208 . Additionally, the controller  212  controls various operating parameters of the electromagnetic energy source  202 , the fluid source  203 , and the fluid delivery system  206 . For example, the controller  212  may be used to control the conditioning of the fluid from the fluid delivery system  206  (e.g., to control whether the fluid is delivered to the interaction zone  208  as a continuous volume of liquid or whether the fluid is atomized into discrete fluid particles). In another example, the electromagnetic energy source  202  includes one or more variable wavelength light sources, and the controller  212  allows a user to control the one or more variable wavelength light sources to change the first and/or second wavelengths λ 1 , λ 2  emitted by the sources  202 A,  202 B. The user may change the first or second wavelengths λ 1 , λ 2  emitted by the fiber optic tip  201  in order to tailor the emitted wavelengths to the absorption properties of different fluids and/or substances. In yet another example, the electromagnetic energy source  202  includes more than two sources of light. A larger number of sources may be used, such that the system  200  is equipped to work with a larger variety of fluids and/or substances. In such a system, the controller  212  may be used to select which of the multiple sources are used. 
     The electromagnetic energy source  202  may include a variety of different lasers, laser diodes, and/or other sources of light. The first and/or second sources  202 A,  202 B may be erbium, chromium, yttrium, scandium, gallium garnet (Er, Cr:YSGG) solid state lasers, which generate light having a wavelength in a range of 2.70 to 2.80 μm. Laser systems used in other examples include an erbium, yttrium, aluminum garnet (Er:YAG) solid state laser, which generates light having a wavelength of 2.94 μm; a chromium, thulium, erbium, yttrium, aluminum garnet (CTE:YAG) solid state laser, which generates light having a wavelength of 2.69 μm; an erbium, yttrium orthoaluminate (Er:YAL03) solid state laser, which generates light having a wavelength in a range of 2.71 to 2.86 μm; a holmium, yttrium, aluminum garnet (Ho:YAG) solid state laser, which generates light having a wavelength of 2.10 μm; a quadrupled neodymium, yttrium, aluminum garnet (quadrupled Nd:YAG) solid state laser, which generates light having a wavelength of 266 nm; an excimer laser, which generates light having a wavelength in a range of approximately 193 nm to 308 nm; and a carbon dioxide (CO2) laser, which generates light having a wavelength in a range of 9.0 to 10.6 μm. 
       FIG. 3  depicts example timing diagrams  300 ,  340 ,  380  illustrating aspects of a method for delivering a substance to a target region in a vapor form. Timing diagram  300  is a graph with the X axis representing units of time  304  and the Y axis representing peak power of emitted radiation at a first wavelength  302  in watts. With reference to  FIG. 1B , the timing diagram  300  illustrates aspects relating to the delivery of the electromagnetic radiation at the first wavelength  144 , which is used to create the vapor bubble  142  in the fluid  104 . At a time of 1 ms, a pulse  306  of the electromagnetic radiation at the first wavelength is emitted by the fiber optic tip. The pulse  306  is highly absorbed by a fluid (e.g., the fluid  104  in  FIG. 1B ) and enables a vapor bubble to form in the fluid. In the timing diagram  300  of  FIG. 3 , the pulse  306  has a width of 50 μs, a pulse energy of 20 mJ, and a peak power of 400 W.  FIG. 3  also depicts a second pulse  308  of the electromagnetic radiation at the first wavelength at a time of 101 ms, indicating that pulses of the electromagnetic radiation at the first wavelength are configured to be output at a frequency of 10 Hz (i.e., causing a period of 100 ms between pulses). 
     Timing diagram  340  is a graph with the X axis representing units of time  344  and the Y axis representing a diameter of a vapor bubble 342 in millimeters. With reference to  FIG. 1B , the timing diagram  340  illustrates aspects of a bubble cycle of the vapor bubble  142  formed after the fluid  104  is excited by the electromagnetic radiation at the first wavelength  144 . At a time of 1 ms, in response to the pulse  306  used to excite the fluid, a vapor bubble  346  is created in the fluid. In the timing diagram  340  of  FIG. 3 , the vapor bubble  346  has a peak diameter of 1 mm and a bubble cycle of nearly 1 ms. As illustrated in the graph  340 , upon being exposed to the electromagnetic radiation at the first wavelength by the pulse  306 , the fluid begins to form the vapor bubble  346 . The vapor bubble  346  increases in diameter, reaches a maximum diameter, and finally collapses over the course of the nearly 1 ms bubble cycle. A second bubble  348  is formed in the fluid as a result of the second pulse  308  and has similar characteristics of the first bubble  346 . 
     Timing diagram  380  is a graph with the X axis representing units of time  384  and the Y axis representing peak power of emitted radiation at a second wavelength  382  in watts. With reference to  FIG. 1C , the timing diagram  380  illustrates aspects of the delivery of the electromagnetic radiation at the second wavelength  184  to the substance  108 , which is used to release the substance  108  in vapor form  182  into the vapor bubble  142 . At a time of 1 ms, a pulse  386  of the electromagnetic radiation at the second wavelength is emitted by the fiber optic tip. In the timing diagram  380  of  FIG. 3 , the pulse  386  has a width of nearly 1 ms, a pulse energy of 1 mJ, and a peak power of 1 W. The pulse  386  is launched at approximately the same time as the pulse  306 , such that the substance to be delivered to the target region is released in vapor form into the vapor bubble  346  during the period of time that the vapor bubble  346  is being created. As illustrated in  FIG. 3 , the duration of the pulse  386  used to release the substance in vapor form into the vapor bubble  346  is substantially longer than the duration of the pulse  306  used to create the vapor bubble. Further, the peak power of the pulse  306  used to create the vapor bubble is substantially larger than the peak power of the pulse  386  used to release the substance in vapor form into the vapor bubble  346 . A second pulse  388  of the electromagnetic radiation at the second wavelength is launched at a time of 101 ms to release the substance in vapor form into the vapor bubble  348 . 
       FIG. 4  depicts fiber optic cables  402  inserted into root canals  404  of a tooth  406  for intra-canal disinfection, cleaning, and/or medication delivery. The fiber optic cables  402  route electromagnetic radiation from an electromagnetic energy source  408  to fiber optic tips of the cables  402 , which extend a substantial distance into the canals  404 . The fiber optic cables  402  may be used with the systems and methods described in the preceding figures to deliver a substance to target regions of the tooth  406 . In  FIG. 4 , the target regions to which the substance is to be delivered include various regions within the length of the canals  404 . The substance to be delivered may include a medicine, cleaning agent, biologically-active particle, antiseptic, and/or antibiotic that is configured to clean the target regions, remove or kill bacteria within the target regions, disinfect the target regions, and/or apply a medical treatment to the target regions. In one example, the substance is iodine, and the iodine is delivered to the target regions of the root canals  404  in vapor form via a vapor bubble. In other examples, the fiber optic cables  402  may be inserted into a tooth cavity or other cavity, opening, or passage of a human body. Such cavities, openings, and passages may have dimensions on the order of the size of the fiber optic cable. 
     Properties of the fiber optic cables  402  and their associated fiber optic tips may be varied to accomplish the cleaning, disinfecting, and/or application of medical treatments to the target regions. For example, the fibers  402  may include single fibers or multi-fiber bundles of various designs (e.g., radially-emitting tips, side-firing tips, forward-firing tips, beveled tips, conical tips, angled tips). Further, the diameter of the fiber optic cables  402  may be varied, and the cables may have a tapered design with the fiber diameter increasing or decreasing over the length of the cable. 
     The fiber optic tips of the fiber optic cables  402  may be positioned at various distances from a target region to which the substance is to be delivered. In certain examples, the fiber optic tips of the fiber optic cables  402  are positioned a number of millimeters from the target region (e.g., positioned a number of millimeters away from the bottom of a canal, where the bottom of the canal is the target region), and in other examples, the fiber optic tips may be positioned directly in contact with the target region (i.e., adjacent to the target region). Further, the fiber optic tips of the fiber optic cables  402  may not be inserted into the canals  404  but may instead be may be centered above the canal, near the entrance to the canal. 
       FIG. 5  illustrates an example system  500  for delivering a medication or cleaning agent  508  to a target area  502  via a plurality of vapor bubbles  510  carrying the medication or the cleaning agent  508  in a vapor form. In  FIG. 5 , a fluid  504  is placed in the target region  502 . As in  FIGS. 1A ,  1 B, and  1 C, the target region  502  is a cavity, canal, opening, or surface to which it is desired that the medication or cleaning agent  508  be delivered. The target region  502  is of a small size, on the order of a size of a fiber optic tip  506 , and may be a cavity, canal, opening, or surface of the human body. In addition to the fluid  504  being placed in the target region  502 , the fiber optic tip  506  is also positioned within the target region  502  or adjacent to the target region  502 . The fiber optic tip  506  is used to emit electromagnetic radiation and is connected via a multi-mode fiber optic cable to an electromagnetic energy source, which generates electromagnetic radiation at first and second wavelengths  503 ,  505 . The fiber optic tip  506  is coated in the substance  508 , such that the electromagnetic radiation  503 ,  505  emitted by the tip  506  interacts with the substance  508  as it is emitted from the tip  506 . 
     In the example of  FIG. 5 , a vapor bubble  510  is created by exposing the fluid  504  to the electromagnetic radiation at the first wavelength  503 . The first wavelength  503  is configured to be substantially absorbed by the fluid  504  and transparent to the substance  508 . Due to the absorption of the radiation at the first wavelength  503  in the fluid  504 , the vapor bubble  510  is created in the fluid  504 . The substance  508  is released in a vapor form into the vapor bubble  510  by exposing the substance  508  to the electromagnetic radiation at the second wavelength  505 . The second wavelength  505  is substantially absorbed by the substance  508 , causing the substance  508  to evaporate into the vapor bubble  510  as it is being formed. The electromagnetic radiation at the first and second wavelengths  503 ,  505  are delivered as light pulses to the fluid  504  and the substance  508 , respectively, and the light pulses of the two wavelengths are launched at substantially similar times (e.g., as illustrated in  FIGS. 3A and 3C ). 
     As illustrated in  FIG. 5 , a plurality of vapor bubbles  510  containing the substance  508  in vapor form may be created. In one example, the plurality of bubbles is created by exposing the fluid  504  to a plurality of light pulses of the first wavelength  503  and exposing the substance  508  to a plurality of light pulses of the second wavelength  505 . Repetitive exposures of the fluid  504  and the substance  508  create a “bubbling” fluid, where each bubble  510  contains the substance  508  in vapor form. Adjusting parameters of the laser radiation at the first and second wavelengths  503 ,  505  alters characteristics of the bubbling effect (e.g., volume of bubbles, rate of bubble production, speed of release of the substance  508 ). In another example, the vapor bubbles  510  are created by pulsing the electromagnetic radiation at the first wavelength  503  and allowing the substance  508  to be exposed to electromagnetic radiation at the second wavelength  505  via a steady state exposure, rather than exposure via pulses. 
     Although the systems described in the preceding figures utilize multiple wavelengths of light to achieve the creation of bubbles and the filling of the bubbles with the substance (e.g., first and second wavelengths  503 ,  505  of  FIG. 5 ), in other examples, only a single wavelength of light is used.  FIGS. 6A and 6B  depict example systems  600 ,  640  that utilize a spraying technique to disperse medication  603  into a vapor bubble  608  for delivery to a target region  602 . As in example systems previously described (e.g., the system of  FIGS. 1A ,  1 B, and  1 C), a fluid  604  and a fiber optic tip  606  are positioned within the target region  602 . The fiber optic tip  606  is configured to emit electromagnetic radiation at a wavelength  601  that is generated by an electromagnetic energy source. The vapor bubble  608  is created within the target region  602  by exposing the fluid  604  to the electromagnetic radiation at the wavelength  601  via the fiber optic tip  606 , as in example systems previously described. 
     In contrast to the systems previously described, in the example systems  600 ,  640  of  FIGS. 6A and 6B , the fiber optic tip  606  is not coated with the medication  603  to be delivered to the target region  602 . Further, the medication  603  to be delivered to the target region  602  is not dispersed within the vapor bubble  608  by exposing the medication  603  to electromagnetic radiation at a second wavelength. Rather, as illustrated in  FIGS. 6A and 6B , the medication  603  is placed in the vapor bubble  608  via a spraying technique. In  FIG. 6A , an apparatus  605  is used to store the medication  603  and to spray the medication  603  into the vapor bubble  608  for delivery to the target region  602 . The apparatus  605  is attached to the fiber optic tip  606 . Similarly, an apparatus  645  in  FIG. 6B  is used to store the medication  603  and to spray the medication  603  into the vapor bubble  608 . The apparatus  645  of  FIG. 6B  is separate from the fiber optic tip  606 . In the systems  600 ,  640 , the medication  603  may be released into the vapor bubble  608  in a solid, liquid, and/or gaseous form. In other example systems, the medication  603  is not sprayed into the vapor bubble  608  but is rather released via a different non-explosive process that does not involve irradiation of the medication  603  at a second wavelength of light (e.g., thermal, mechanical, or electrical means to release the medication  603  into the vapor bubble  608 ). 
       FIG. 7  depicts a block diagram of an example system utilizing an electromagnetic energy source  702  with a plurality of laser sources  703  to deliver a medicine to a target region  710  in a vapor form. In the system  700  of  FIG. 7 , the electromagnetic energy source  702  includes n separate electromagnetic energy sources  703  (e.g., lasers, laser diodes) configured to produce electromagnetic radiation at wavelengths λ 1 , λ 2 , λ 3 , λ 4 , . . . λ n . The n electromagnetic energy sources are utilized to enable a variety of different fluids and medicines  705  to be used with the system  700 . As noted previously, forming a vapor bubble and releasing medicine into the vapor bubble may require that the fluid and the medicine be matched with particular light emitting sources (i.e., the fluid and the medicine must have high absorption properties at the wavelengths of light of the particular light emitting sources). Thus, by including the n electromagnetic energy sources  703 , a wider variety of fluids and/or medicines may be used with the system  700 . The n electromagnetic energy sources  703  may be used to expose the fluid to create the vapor bubble and/or expose the medicine  705  to be dispersed in the vapor bubble. 
     The electromagnetic energy source  702  is connected to both a multi-mode fiber optic cable  704  and a controller  712 . The multi-mode fiber optic cable  704  routes the electromagnetic energy generated by the n sources  703  to a fiber optic tip  701 . The fiber optic tip  701  may be coated with any of n different medicines  705  (e.g., various disinfectant solutions or medications used for injections). The fiber optic tip  701  is connected to an interaction zone  708  (e.g., positioned within the interaction zone  708 ) and delivers electromagnetic radiation to the interaction zone  708 . The interaction zone  708  is a volume of space that extends into the target region  710  or that is adjacent to the target region  710 . The interaction zone  708  is also connected to a fluid delivery system  706 , which is configured to supply a fluid to the interaction zone  708 . 
     The controller  712  is connected to both the electromagnetic energy source  702  and to the fluid delivery system  706 , and is used to synchronize the delivery of the electromagnetic radiation and the fluid to the interaction zone  708 . Additionally, the controller  712  includes a graphical user interface (GUI) that allows a user to control various operating parameters of the system  700 . For example, the GUI allows the user to select the fluid and the medication  705  that are to be used with the system  700 . Based on the selections, the controller  712  selects certain sources of the n light sources to be used (i.e., the controller  712  selects sources from the n light sources  703  that are best matched to the user&#39;s selected fluid and medication). The GUI of the controller  712  also includes a laser selector that allows the user to manually choose which of the n light sources  703  are to be used for exposing the fluid and dispersing the medicine  705  into the vapor bubble. 
       FIG. 8  is a flowchart  800  illustrating an example method for delivering a substance to a target region in a vapor form. At  802 , a fluid is placed within an interaction zone. The interaction zone is a volume that extends into the target region or that is adjacent to the target region. At  804 , an electromagnetic radiation emitting fiber optic tip is positioned within the interaction zone. The fiber optic tip contains the substance that is transparent to a first wavelength of energy and that substantially absorbs a second wavelength of energy. At  806 , a vapor bubble is created within the interaction zone by exposing the fluid to electromagnetic radiation at the first wavelength. The electromagnetic radiation at the first wavelength is substantially absorbed by the fluid in the interaction zone. At  808 , the substance is released in a vapor form into the vapor bubble by exposing the substance to electromagnetic radiation at the second wavelength. The electromagnetic radiation at the first and second wavelengths is emitted by the fiber optic tip. 
     While the disclosure has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the embodiments. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents. 
     It should be understood that as used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise. Further, as used in the description herein and throughout the claims that follow, the meaning of “each” does not require “each and every” unless the context clearly dictates otherwise. Finally, as used in the description herein and throughout the claims that follow, the meanings of “and” and “or” include both the conjunctive and disjunctive and may be used interchangeably unless the context expressly dictates otherwise; the phrase “exclusive of” may be used to indicate situations where only the disjunctive meaning may apply.