Patent Publication Number: US-2023149734-A1

Title: Phototherapy apparatuses and methods

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. Pat. Application No. 16/379,226 filed on Apr. 9, 2019, which is divisional of U.S. Pat. Application No. 15/143,277 filed on Apr. 29, 2016 and issued as U.S. Pat. No. 10,369,376 on Aug. 6, 2019, the entire contents each of which are incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
     Not Applicable. 
    
    
     BACKGROUND 
     The present disclosure relates generally to phototherapy and, more specifically, to apparatuses and methods for effectively administering phototherapy. 
     One instance where phototherapy is utilized is the treatment of jaundice. It is fairly common for neonates to be born clinically jaundiced. Jaundice, or hyperbilirubinemia, results from increased production and transiently impaired elimination of the pigment bilirubin. Neonates affected by jaundice can show persistent high levels of unconjugated bilirubin. High levels of unconjugated bilirubin can lead to kernicterus, a condition involving deposition of bilirubin in the brain, which leads to deficits in cognition, neuromuscular tone and control, and hearing, and even death. The most common therapy for neonatal hyperbilirubinemia or jaundice is phototherapy. The efficacy of phototherapy can depend on irradiance (light intensity), spectral range (light wavelength), exposed skin surface area (Body Surface Area (BSA)), and duration of exposure. Other instances where phototherapy may be used are psoriasis, atopic dermatitis, eczema, and acne vulgaris, to name a few. 
     BRIEF SUMMARY 
     The present disclosure provides phototherapy apparatuses and methods. In particular, the present disclosure provides phototherapy apparatuses configured to diffusely transmit light emitted from a light source to a target surface and thereby to a patient. 
     In one aspect, the present disclosure provides a phototherapy treatment apparatus including a bed having (i) at least one of a transparent or a translucent material, (ii) a surface having a plurality of microstructures, and (iii) a plurality of side surfaces. The phototherapy treatment apparatus further includes a housing holding the bed, and a light source supported by the housing. The light source being positioned in the housing so that the light generated by the light sources is directed at one of the plurality of side surfaces and is transmitted through the transparent or translucent material of the bed and through the plurality of microstructures such that the light exits the plurality of microstructures having a more diffusive distribution, thereby enhancing the treatment of an ailment when a patient is lying on the bed. 
     In another aspect, the present disclosure provides a phototherapy treatment apparatus including a bed having (i) at least one of a transparent or a translucent material, and (ii) a surface having a plurality of microstructures. The surface is formed integrally with the bed. The phototherapy treatment apparatus further includes a light source constructed and arranged to generate light that is transmitted from the light source through the transparent or translucent material of the neonate bed and through the plurality of microstructures such that the light exits the plurality of microstructures having a more diffusive distribution, thereby enhancing the treatment of an ailment when a patient is lying on the bed. 
     In yet another aspect, the present disclosure provides a phototherapy treatment method including placing a patient on a bed having at least one of a translucent or transparent material, generating light from a light source; and transmitting the generated light through the material of the bed and through a plurality of microstructures located on a surface of the bed such that the light exits the plurality of microstructures having a more diffusive distribution so as to enhance the treatment of an ailment of the patient placed on the bed. 
     The foregoing and other aspects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims and herein for interpreting the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention will be better understood and features, aspects and advantages other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such detailed description makes reference to the following drawings. 
         FIG.  1    is a perspective view of a phototherapy treatment apparatus according to one non-limiting example of the present disclosure. 
         FIG.  2    is a cross-sectional view of a bed of the phototherapy treatment apparatus of  FIG.  1    illustrating light traveling through a light channel of the bed, according to one aspect of the present disclosure. 
         FIG.  3    is a perspective view of a phototherapy treatment apparatus according to another non-limiting example of the present disclosure. 
         FIG.  4    is an exploded view of a bed assembly of the phototherapy treatment apparatus of  FIG.  3   . 
         FIG.  5    is an exploded view of an LED module assembly of the phototherapy treatment apparatus of  FIG.  3     
         FIG.  6    is a perspective view of a bed of the phototherapy treatment apparatus of  FIG.  3   . 
         FIG.  7    is a cross-sectional view of the bed of  FIG.  6    taken along line 7-7. 
         FIG.  8    is a cross-sectional view of the bed of  FIG.  6    taken along line 8-8. 
         FIG.  9    is a cross-sectional view of a bed assembly of the phototherapy treatment apparatus of  FIG.  3    taken along line 9-9. 
         FIG.  10    is a zoomed-in view of the section of  FIG.  9    indicated by line 10-10. 
         FIG.  11    is a zoomed-in view of the section of  FIG.  9    indicated by line 11-11. 
         FIG.  12    is a cross-sectional view of the bed of  FIG.  6    illustrating light traveling through a light channel of the bed and being dispersed by a plurality of microstructures on treatment surface of the bed, according to one aspect of the present disclosure. 
         FIG.  13 A  is an illustration of a radial crack according to one aspect of the present disclosure. 
         FIG.  13 B  is an illustration of a conical crack according to one aspect of the present disclosure. 
         FIG.  13 C  is an illustration of a lateral crack according to one aspect of the present disclosure. 
         FIG.  14    is a graph illustrating a normalized light irradiance profile as a function of longitudinal distance along a treatment surface without a plurality of microstructures. 
         FIG.  15    is a graph illustrating a normalized light irradiance profile as a function of longitudinal distance along a treatment surface with a plurality of microstructures. 
         FIG.  16    is a graph illustrating a relative spectral power distribution as a function of wavelength for an LED of the phototherapy treatment apparatus of  FIG.  3    and for bilirubin absorption according to one non-limiting example of the present disclosure. 
         FIG.  17    a schematic illustration of the components of the phototherapy treatment apparatus of  FIG.  3    according to one non-limiting example of the present disclosure. 
         FIG.  18    is a flow chart outlining the steps for operating a phototherapy treatment apparatus according to one non-liming example of the present disclosure. 
         FIG.  19    is a perspective view of a phototherapy treatment apparatus including a heater according to another non-limiting example of the present disclosure. 
         FIG.  20    is a perspective view of a phototherapy treatment apparatus configured for piecewise assembly according to another non-limiting example of the present disclosure. 
         FIG.  21    is a perspective view of a phototherapy treatment apparatus including a plurality of foldable unit cells according to another non-limiting example of the present disclosure. 
         FIG.  22    is a perspective view of a phototherapy treatment apparatus including a branched structure for light transmission according to another non-limiting example of the present disclosure. 
         FIG.  23    is a perspective view of a phototherapy treatment apparatus including a goose necked light source according to another non-limiting example of the present disclosure. 
         FIG.  24    is a perspective view of a disposable mattress usable with phototherapy treatment apparatuses described herein. 
         FIG.  25    is a perspective view of a surface profile of a bed surface treated by CNC. 
         FIG.  26    a perspective view of a surface profile of a bed surface treated by CNC and laser etching. 
         FIG.  27    is a perspective view of a surface profile of a bed surface treated by CNC and sandblasting. 
         FIG.  28    is graph illustrating a normalized light emittance as a function of longitudinal position along the bed surface of  FIG.  25    at two different latitudinal positions. 
         FIG.  29    is graph illustrating a normalized light emittance as a function of longitudinal position along the bed surface of  FIG.  26    at two different latitudinal positions 
         FIG.  30    is graph illustrating a normalized light emittance as a function of longitudinal position along the bed surface of  FIG.  27    at two different latitudinal positions 
     
    
    
     DETAILED DESCRIPTION 
     The use of the term “light” herein is a term that is synonymous with “electromagnetic radiation,” and is not meant to be limited to a specific wavelength range within the electromagnetic spectrum unless specifically stated. 
     Current phototherapy approaches for treating jaundice in neonates use a fluorescent lamp, a halogen lamp, or LEDs, which shine light directly on the neonate. The light sources are typically kept a specified distance away from the neonate (e.g., at least 35 cm) and mounted on top of neonatal bassinets, incubators and/or warmers. The American Association of Pediatrics (AAP) requires that phototherapy devices used to treat jaundiced neonates output an average light intensity of 30 µW/cm 2 /nm, and that the ratio between the minimum and maximum light intensity be greater than 0.4 These approaches suffer from a number of shortcomings, such as: 1) causing the neonate to lose body water due to warming of the ambient air around; 2) potentially exposing the neonate’s naked eye to the treatment light; 3) distributing the light intensity unevenly on the BSA; and 4) requiring additional space in neonatal intensive care units (NICUs). Currently available equipment also has relatively high-power requirements and occupy a lot of space, rendering the equipment unsuitable for use in remote places of developing countries and expensive to ship. 
     It would therefore be desirable to have portable phototherapy apparatuses that are configured to efficiently output uniform, or diffusive light irradiance to a patient. Additionally, the portability of the apparatuses can enable at-home treatment. It would also be desirable for such phototherapy apparatuses that consume less power, which translates to less heat produced by light sources/equipment and enables more efficient heat dissipation. Further, less heat produced can aid in preventing dehydration while treating the patient. As will be described below, apparatuses described herein facilitate a reduction in a gap between a light source and a patient, and use a controllable medium to channel light thereby achieving power requirements that are fractional when compared with the prior art. 
       FIG.  1    illustrates a perspective view of one non-limiting example of a phototherapy treatment apparatus  100  of the present disclosure. The phototherapy treatment apparatus  100  includes a bed  102 , a transition device  104 , and a light source  106 . The bed  102  includes a top side  108 , a bottom surface  110 , and a plurality of side surfaces  112 . The bed  102  may include a material that is transparent and/or translucent to electromagnetic radiation in the visible spectrum and its neighborhood (e.g., between approximately 100 nanometers (nm) and 900 nm). Bed  102  may additionally include a material having a higher refractive index than air. Example materials for bed  102  include one or more polymers, such as, polycarbonate (PC), polymethyl methacrylate (PMMA) and/or polystyrene (PS). 
     The top side  108  of the bed  102  includes a treatment surface  114  configured to diffusely transmit light emitted from light source  106  to a neonate or patient positioned on the top side  108 . The diffuse transmission characteristics of the treatment surface  114  may be obtained by mechanical, chemical, or photic processes that produce microstructures  116  on the treatment surface  114 . The microstructures  116  may comprise, for example, discolored char particles, voids, and/or micro-cracks. The individual or collective action of these voids, micro-cracks, chars, or any other suitable microstructures can be responsible for diffusely scattering radiation transmitted from the treatment surface  114  through the microstructures  116 . Examples of processes that may be used to create microstructures  116  include one or more of CNC machining, laser engraving, sand blasting, chemical engraving, and/or other suitable mechanical, chemical, or photic operations. Alternatively or additionally, the microstructures  116  may be formed on a thin layer than can be coated or embedded on the treatment surface  114 . The plurality of side surfaces  112  of the bed  102  includes an incident surface  118 , which is configured to receive the light emitted from light source  106 . 
     In some non-limiting examples, light source  106  may be configured to emit light in a broadband spectrum spanning between, but not limited to, the ultraviolet and infrared spectrums. In these non-limiting examples, the light source  106  may be in the form of a lamp or solar radiation. In other non-limiting examples, light source  106  may be configured to emit light in a narrow band in the visible spectrum and its neighborhood (e.g., between approximately 100 nm and 900 nm). In these non-limiting examples, the light source  106  may be in the form of a light emitting diode (LED) or a laser. In some non-limiting examples, the light source  106  may be configured to emit light that are focused towards a specific phototherapy application. For example, the light source  106  may be configured to emit light at a wavelength, or range of wavelengths, capable of photodissociating bilirubin in the blood of a patient (e.g., a neonate). Alternatively or additionally, the light source  106  may be configured to emit light between approximately 280 nm and 320 nm for treating eczema, atopic dermatitis, vitiligo, and/or psoriasis. Alternatively or additionally, the light source  106  may be configured to emit visible light to facilitate treating seasonal affective disorder (SAD) and/or bipolar disorder. Alternatively or additionally, the light source  106  may be configured to emit light between approximately 100 nm and 280 nm for treating wound healing and/or inhibiting bacterial growth. Alternatively or additionally, the light source  106  may be configured to emit infrared light for treating hypothermia. It should be appreciated that the phototherapy treatments listed above are not meant to be limiting in any way and the light source  106  can be configured to emit light to facilitate phototherapy treatments for a variety of ailments. 
     In operation, light emitted from light source  106  travels through the transition device  104  to incident surface  118 . The transition device  104  can be used to serve one or more functions including, but not limited to, transmitting the light from the light source  106  to the incident surface  118 , focusing, scattering, or diffusing the light, shifting the wavelength of the light emitted from the light source  106 , filtering the light to pass only a specific bandwidth of wavelengths through, and/or amplifying the intensity of the light. In one non-limiting example, after passing through the transition device  104 , the light emitted from light source  106  is filtered to a wavelength capable of photodissociating bilirubin to treat a jaundiced patient. In another non-limiting example the transition device  104  may focus the light along a substantial portion or, the entire length, of incident surface  118 . In still other non-limiting examples, the light emitted from the light source  106  can be filtered to a wavelength capable of treating psoriasis, bipolar disorder, eczema, and SAD, to name a few. 
     As shown in  FIG.  2   , once the light (shown as light rays) emitted from the light source  106  reaches the incident surface  118 , the light transmits through the incident surface  118  and enters a light channel  122  defined between the top side  108  and the bottom surface  110  of the bed  102 . The light that enters the light channel  122  can be emitted into the light channel  122  at a viewing angle θ v  such that total internal reflection (TIR) is achieved, as described below. 
     There are two conditions for TIR to occur: (1) light should travel from denser to rarer medium (i.e., from a higher index of refraction to a lower index of refraction), and (2) an angle of incidence in the denser medium should be greater than a critical angle. As described above, bed  102  can be fabricated from a material with a higher index of refraction than air. Bed  102  therefore satisfies the first condition for TIR. The second constraint can be satisfied by proper design of the viewing angle θ v  defined by the light entering the light channel  122  and the specific material from which the bed  102  is fabricated. According to the second condition, TIR can be achieved when light traveling through the light channel  122  intersects a medium boundary surface  124  formed between either the top surface  108  or the bottom surface  110  and the air at an angle of incidence θ i  larger than a critical angle θ critical  (i.e., θ i  &gt; θ critical ). The critical angle θ critical  is measured with respect to an axis  126  normal to the medium boundary surface  124 . The critical angle θ critical  is determined based on the index of refraction of air n 2  and the index of refraction of the bed material n1, in accordance with Snell’s law shown below. 
     
       
         
           
             
               θ 
               
                 c 
                 r 
                 i 
                 t 
                 i 
                 c 
                 a 
                 l 
               
             
             = 
             arcsin 
             
               
                 
                   
                     
                       n 
                       2 
                     
                   
                   
                     
                       n 
                       1 
                     
                   
                 
               
             
           
         
       
     
     The angle of incidence θ i  can be related to a semi-viewing angle θ sv , defined by the light traveling in the light channel  122 , by: 
     
       
         
           
             
               θ 
               i 
             
             = 
             90 
             − 
             
               θ 
               
                 s 
                 v 
               
             
             . 
           
         
       
     
     Substituting in the constraint that θ i  &gt; θ critical , the semi-viewing angle θ sv  can be related to the critical angle θ critical  by: 
     
       
         
           
             
               θ 
               
                 s 
                 v 
               
             
             &lt; 
             90 
             − 
             arcsin 
             
               
                 
                   
                     
                       n 
                       2 
                     
                   
                   
                     
                       n 
                       1 
                     
                   
                 
               
             
             . 
           
         
       
     
     As shown by the illustrated non-limiting example of  FIG.  2    and as described by equations 1-3, light enters the light channel  122  of the bed  102  at a viewing angle θ v , generally defined as an off-axis angle from a centerline  128 , defined by the light source  106 , where the luminous intensity is approximately half of a peak value. The viewing angle θ v  can be divided into two semi-viewing angles θ sv , both measured between the light and the centerline  128  of the light source  106 . The centerline  128  can be parallel to the top surface  108 , and the axis  126 , which is normal to the top and bottom surfaces  108 ,  110 , forms a right angle with the central-horizontal axis  128 . As such, due to geometrical constraints, the angles of incidence θ i , formed between the outermost light and the axis  126 , are complementary to the corresponding semi-viewing angles θ sv  (each semi-viewing angle added to the corresponding angle of incidence would equal a right angle). Therefore, each angle of incidence θ i  is equal to ninety degrees minus the corresponding semi-viewing angle θ sv . To ensure that TIR is achieved, ninety degrees minus the corresponding semi-viewing angle θ sv  is maintained below the critical angle θ critical , as determined by the equations 1-3 above. Thus, once the index of refraction of the bed  102  material is known, a minimum viewing angle θ v  for the light entering the light channel  122  can be defined to ensure TIR. 
     It should be appreciated that the example described above with reference to  FIG.  2    does not account for when the centerline  128  of the light source  102  is not parallel to the top surface  108  and/or the bottom surface  110 . In such a case, a tilt angle θ tilt  can be defined as the angle between the centerline  128  of the light source  106  and a central-horizontal axis defined between the top surface  108  and the bottom surface  110 . The semi-viewing angle of equation 3 can be modified to account for the tilt angle θ tilt , as defined below. 
     
       
         
           
             
               θ 
               
                 s 
                 v 
               
             
             &lt; 
             
               
                 90 
                 + 
                 
                   θ 
                   
                     t 
                     i 
                     l 
                     t 
                   
                 
               
             
             − 
             arcsin 
             
               
                 
                   
                     
                       n 
                       2 
                     
                   
                   
                     
                       n 
                       1 
                     
                   
                 
               
             
           
         
       
     
     The TIR achieved through the light channel  122  of the bed  102  ensures that a maximum intensity of light can be delivered to a patient on the treatment surface  114  with minimal losses due to refraction. Alternatively or additionally, the bed  102  may be coated, except on the treatment surface  114  and the incident surface  118 , with a reflective backing to further prevent light leakage from the light channel  122 . The TIR can be maintained throughout the light channel  122  until the light contacts one or more of the plurality of microstructures on the treatment surface  114 . After contacting one or more of the plurality of microstructures on the treatment surface  114 , the light can be diffusely transmitted from the treatment surface  114  to a patient positioned on the treatment surface  114 . In this way, the phototherapy treatment apparatus  100  is configured to efficiently transmit treatment light from the light source  106  to a patient positioned on the treatment surface  114  such that the treatment light transmitted to the patient defined a generally uniform, or diffuse, profile. The efficient transmission of light through the light channel  122  of the bed  102  to the treatment surface  114  enables the phototherapy treatment apparatus  100  to consume less power, which translates to less heat produced by the light sources  106 , and enables more efficient heat dissipation and lower power requirements. 
       FIGS.  3 - 12    illustrate another non-limiting example of a phototherapy treatment apparatus  300  of the present disclosure. Referring to  FIG.  3   , the phototherapy treatment apparatus  300  includes a control unit  302  in communication with a bed assembly  304 . Control unit  302  includes a port  308  configured to be in communication with the bed assembly  304 , a display  310 , and a keypad  312 . The port  308  can be in direct wired communication with bed assembly  304 , or in wireless communication with bed assembly  304 . Display  310  is configured to display operational data of the bed assembly  304  (e.g., total treatment time, treatment time remaining, temperature, light intensity, alarms, etc.). Keypad  312  is configured to control certain operating parameters of the bed assembly  304 , as described below. It should be appreciated that control unit  302  includes electronics that enable a user to control the operating parameters of the bed assembly  304 . 
     The bed assembly  304  includes a housing  314  and an input  316  for receiving power (e.g., power from an AC or DC power source). In the illustrated non-limiting example, the phototherapy treatment apparatus  300  defines a substantially cuboid shape. In other non-limiting examples, the phototherapy treatment apparatus  300  may define another polyhedron shape, or any other suitable shape that is deemed appropriate for supporting a patient and allowing light to treat the patient. 
     Turning to  FIG.  4   , the housing  314  of the bed assembly  304  includes a top plate  318  and a bottom plate  320  spaced apart such that both an inner connector plate  322  and an outer connector plate  324  can be arranged between the top and bottom plates  318  and  320 . The top plate  318  defines a central opening  326  dimensioned to receive a cover pad  346 , and may include the input  316  and a plurality of fastener receiving columns  330 . The bottom plate  320  includes a plurality of plate mounting apertures  332 , a plurality of LED module mounting apertures  334 , and two opposing fan housings  336 . Each of the plurality of plate mounting apertures  332  are configured to align with a corresponding one of the fastener receiving columns  330  of the top plate  318 . When assembled, a fastening element can be received by each of the plurality of plate mounting apertures  332  and threaded into the corresponding fastener receiving column  330  thereby fastening the top plate  318  to the bottom plate  320 . In the illustrated non-limiting example, the top  318  and bottom plates  320  may be coupled using a plurality of fasteners. In other non-limiting examples, the top  318  and bottom  320  plates may be coupled, for example, by an adhesive or any other suitable coupling mechanism. 
     The inner and outer connector plates  322  and  324  each include a plurality of cooling apertures  338  defining a vent. In an embodiment, cooling apertures  338  are arranged around a periphery of the plates  322 ,  324  and allow air flow between the housing  314  and the surroundings. When assembled (as shown in  FIGS.  3  and  9 - 11   ), the inner connector plate  322  and the outer connector plate  324  can be fastened between the top plate  318  and the bottom plate  320  with the inner connector plate  322  arranged circumferentially within the outer connector plate  324 . 
     The bed assembly  304  further includes a pair of light emitting diode (LED) modules  340 , a pair of fans  342  received within the two opposing fan housings  336  of the bottom plate  320 , a bed  344 , the pad or cover pad  346 , and a bed gasket  348 . The pad  346  may be fabricated in an example embodiment from a silicone material and can be configured to provide a soft and comfortable surface or cushion for the neonate. Additionally, pad  346  can be configured to transmit the light emitted from the pair of LED modules  340  and may act as a buffer to balance out light intensity variations across the bed  344 . Further, the pad  346  can be sealingly engaged to the surface of the bed  344  and can act as a seal to prevent liquids from entering, and potentially damaging, the internal components within the housing  314 . In another non-limiting example, the pad  346  may be integrated into the bed  344 . The bed gasket  348  is dimensioned to be arranged around a periphery of the bed  344  and can be arranged between the bed  344  and the pad  346 . The bed  344  and the pad  346  are further dimensioned such that a periphery of the pad  346  is in contact with the top plate  318 , such that the center of the pad  346  is accessible through the central opening  326  of the top plate  318 . 
     It should be appreciated that each of the pair of LED modules  340  can include similar components. The following description therefore can apply to each of LED modules  340 . With reference to  FIG.  5   , each pair of LED modules  340  includes a heat sink  350 , a thermal interface  352 , an LED printed circuit board  354 , a spacer plate  356 , and a module housing  358 . The heat sink  350  includes a finned side  360  and a non-finned side  362 . The finned side  360  includes a plurality of fins  364  to provide the heat sink  350  with a greater surface area and thereby provide improved heat dissipation from the printed circuit board  354  during operation. The non-finned side  362  includes a plurality of threaded apertures  365  spaced along a length of the heat sink  350 . 
     The thermal interface  352  is arranged between the heat sink  350  and the printed circuit board  354 , and is dimensioned to increase a contact surface area and improve heat transfer from the printed circuit board  354  to the heat sink  350 . The printed circuit board  354  is arranged between the thermal interface  352  and the spacer plate  356 , and includes a non-LED side (not shown) and an LED side  366 . When assembled, the non-LED side engages the thermal interface  352  and the LED side  366  engages the spacer plate  356 . The LED side  366  includes a plurality of LEDs  368  incrementally spaced along a length of the printed circuit board  354 . The spacer plate  356  is arranged between the printed circuit board  354  and the module housing  358 . The module housing  358  includes a mounting flange  370 , a bed mating surface  372 , and a housing recess  374 . The bed mating surface  372  is arranged to engage with the bed  344  when the bed assembly  304  is assembled. The housing recess  374  is configured to receive the heat sink  350 , the thermal interface  352 , the printed circuit board  354 , and the spacer plate  356 . 
     Each of the thermal interface  352 , the printed circuit board  354 , the spacer plate  356 , and the module housing  358  includes a plurality of mounting apertures that align with the plurality of threaded apertures  365  of the heat sink  350 . When the pair of LED modules  340  are assembled, a fastening element (e.g., a threaded bolt or screw) can be inserted through the plurality of mounting apertures formed in the thermal interface  352 , the printed circuit board  354 , the spacer plate  356 , and the module housing  358 . The fastening elements can then be threaded into the plurality of threaded apertures  365  to secure the heat sink  350 , thermal interface  352 , the printed circuit board  354 , and the spacer plate  356  within the module housing  358 . 
     Turning to  FIGS.  6 - 8   , the bed  344  includes a top side  374 , a bottom side  376 , a plurality of side surfaces  378 , and a plurality of mounting apertures  379 . The plurality of mounting apertures  379  can be configured to receive a fastening element (as shown in  FIG.  4   ) to couple the bed  344  to the pad  346  and also to couple the bed  344  to the bottom plate  320 . The top side  374  of the bed  344  includes a peripheral surface  380  and a treatment surface  382 . The treatment surface  382  includes a plurality of microstructures  384  (shown in  FIG.  12   ) and can define a substantially concave shape or concave channel. The concave shape defined by the treatment surface  382  can be dimensioned such that, when a patient is placed onto the treatment surface  382  during operation, light emitted from the treatment surface  382  are focused at an angle, increasing body exposure to the light, as described in detail below. In other non-limiting examples, the treatment surface  382  may define an alternative shape, for example a flat shape, as desired. 
     The plurality of microstructures  384  can be generally defined as purposefully placed imperfections, capable of dispersing light. In operation, it is desirable to have the treatment surface of bed  344  transfer light from within the bed  344  to the patient (e.g., a neonate) over a wide range of angles to maximize BSA and over a generally uniform, or diffuse, gradient flux. The plurality of microstructures  384  enable the bed  344  to provide such generally uniform or diffuse gradient flux. Bed  344  is also easily manufactured because processes for making the bed can be easily automated. The plurality of microstructures  384  can again be voids, micro-cracks, chars, any combination thereof, or any other suitable microstructures capable of dispersing light, and can be formed by one or more of CNC machining, laser engraving, sand blasting, chemical engraving, or any other suitable mechanical, chemical, or photic operations, as will be described in detail below. 
     Two of the plurality of side surfaces  378  in the illustrated non-limiting example are incident surfaces  386 , which receive incident treatment light from the plurality of LEDs  368  during operation, as described in detail below. The other two of the plurality of side surfaces  378  include fan clearance recesses  388  to allow clearance for the two opposing fan housings  336  of the bottom plate  320 . A light channel  389  can be defined between the top side  374  and the bottom side  376  along which light can travel from one of the incident surfaces  386  to the other incident surface  386 . In some non-limiting examples, one or more of the bottom side  376 , the peripheral surface  380 , and the side surfaces  378  which are not incident surface  386  may be covered with an anti-reflection coating or material configured to reflect light emitted by the plurality of LEDs  368 . 
     Turning to  FIGS.  9 - 11   , the fan housing  336  further defines a fan chamber  390  and a fan recess  392 , which receives the fan  342  within the fan housing  336 . With reference to  FIG.  11   , when LED modules  340  are assembled within the housing  314 , each LED module  340  is arranged such that the bed mating surface  372  of the module housing  358  sits flush with the incident surface  386  of the bed  344 . In this arrangement, the plurality of LEDs  368  of the LED printed circuit board  354  can directly emit treatment light onto the incident surface  386  during operation. Also, this arrangement can align the plurality of LEDs  368  with a centerline  395  defined by the light channel  389 . 
     An air passageway  394  is formed between the heat sink  350  of the LED module  340  and the inner connector plate  322 . The air passageway  394  extends around the bed  344  within the housing  314  to facilitate air flow. The finned sides  360  of the heat sinks  350  border this air passageway  394 , allowing the plurality of fins  364  to transfer heat, either passively or actively, away from the LED module  340  and into the air passageway  394 . In the illustrated non-limiting example, during operation, the fans  342  provide air flow that flows between the surroundings through the cooling apertures  338  and to the air passageway  394 . This allows the heat sink  350  to more efficiently transfer heat away from the LED module  340 . It should be appreciated that in some non-limiting examples, the bed assembly  304  may not include the fans  342  and the heat sinks  350  may be sufficient to passively cool the printed circuit boards  354 . 
       FIG.  12    is a schematic diagram illustrating a non-limiting example of the treatment light traveling through the light channel  389  of the bed  344 . In  FIG.  12   , the treatment light have been generated by a light source and are illustrated as light rays  398  that are emitted at a viewing angle such that TIR is achieved. That is, a viewing angle defined by the LEDs  368  can be sufficient to ensure that TIR occurs through the light channel  389 , as illustrated in  FIG.  2    and defined by equations 1-3 above. 
     The light rays  398  transmitting through light channel  389  are totally internally reflected between the top and bottom sides  374 ,  376  of the bed  344  several times before reaching treatment surface  382 . At treatment surface  382 , the light rays  398  are transmitted through the microstructures  384  such that the light rays exit the microstructures  384  with a more diffusive distribution than the light rays  398  that entered the microstructures. That is, the light rays are generally evenly dispersed by the plurality of microstructures  384  in all directions above the light channel  389  thereby providing a diffuse profile at the treatment surface  382 . Although the illustrated non-limiting example shows light rays  398  emitted at two different viewing angles, in other non-limiting examples, the light rays  398  may be emitted at the same or different viewing angles to suit operational conditions. 
     As shown in  FIG.  12   , the plurality of microstructures  384  can intercept the light traveling through the light channel  389  on its natural trajectory and disperse it to prevent TIR along the treatment surface  382 . The plurality of microstructures  384  serve the purpose of making the angle of incidence, θ i , less than the critical angle θ critical , As described above, some of the commonly used methods to induce surface irregularities, or microstructures, comprise machining, chemical etching, and laser etching. Irrespective of the method of manufacture, kinetic and thermal energy of the incident particles can be highly relevant parameters to explain the damage (i.e., the formation of microstructures). The impacting particles of mechanical operations can be described through kinetic energy dissipated during an erosion process, and the impacting particles in photic and chemical processes can be described through thermal energy. 
     Material impacted by a projectile is subject to plastic deformation and/or fracture. The types of fracture—radial, circumferential, lateral, or conical-depend on the size distribution of inherent cracks, a fracture toughness of material, and a magnitude of a dynamic elastic stress field created during impact (kinetic energy of impacting particles). These fractures manifest themselves as cracks, voids, and remnant char particles that are collectively referred to as the plurality of microstructures  384  herein. 
     Cracks may be considered primary microstructures as they grow deeper into the treatment surface  382 , during manufacture, and tap into a higher percentage of light flux inside the bed  344 . Cracks can be divided into three categories, namely radial cracks, lateral cracks, and conical cracks, as shown in  FIGS.  13 A-C . Radial cracks ( FIG.  13 A ) extend from voids and, at any given time, can have approximately the same length. Conical cracks ( FIG.  13 B ) may dominate in softer materials due to plastic deformation, but can appear in the form of circumferential cracks in harder materials. Lateral cracks ( FIG.  13 C ) may be formed after the penetration has terminated, deriving from the relatively large in-plane tensile stresses of the appropriate orientation formed due to the interaction of the plastic wave with the unloading elastic wave. 
     A number of cracks at an impact site can depend on an impact speed V, and the thickness, h, of the bed  344 . Assuming the transverse bending energy can be neglected, as the thickness is small compared to the other dimensions of the bed  344 , the number of cracks on the treatment surface  382  can be approximated by: 
     
       
         
           
             n 
             ≈ 
             
               
                 
                   
                     
                       
                         E 
                         h 
                       
                       Γ 
                     
                   
                 
               
               
                 1 
                 / 
                 3 
               
             
             
               
                 
                   
                     
                       V 
                       c 
                     
                   
                 
               
               
                 1 
                 / 
                 2 
               
             
           
         
       
     
     Where E is the Bulk Modulus, h is a thickness of the bed  344 , Γ is the fracture energy, V is a velocity of an impact, and c is a velocity of sound in the bed  344 . The velocity of an impact V may depend on the specific manufacturing process used to manufacture the treatment surface  382 . For example, a CNC operation may be correlated to a speed that the router hits the treatment surface  382  and, for sand blasting, it may be correlated to a speed that the sand hits the treatment surface  382 . In some non-limiting examples, the treatment surface  382  of the bed  344  may comprise between approximately 3797 and approximately 6132 cracks per square inch. In other non-limiting examples, there can be more smaller cracks, which can be a result of the machining process, and that can also contribute to light dispersion. In these non-limiting examples, the treatment surface  382  of the bed  344  may comprise greater than approximately  1000  cracks per square inch. 
     In some non-limiting examples, a length of the cracks formed in the treatment surface  382  during machining may be between approximately 20 micrometers (µm) and 4000 µm, for radial cracks, and a depth of damage can be between approximately 20 µm and approximately 600 µm. 
     Voids and char particles may be considered as secondary microstructures as their size and shape can be governed by the nature of the projectile (e.g., router, sand, laser beam, or etchant). Voids can be craters left behind from the deformation process. In order to achieve a generally uniform distribution of voids, a balance between the diameter of the voids and their distribution may need to be balanced. Large voids can be undesirable as they alter the topography and might create a new surface without any microstructures. Closely compacted voids can have intertwined cracks, which may make the surface unstable and hot-spots for crack propagation. Keeping the light-diffusing capabilities and the usability of the bed  344  intact, voids on the treatment surface  382  can be between 20 µm and 200 µm in diameter (D v ), and should be spaced 2D v  &lt; C v  &lt; 10, where C v  is the center-to-center distance between voids, for minimum interaction between the plurality of microstructures  384  and a diffuse light profile. 
     Char particles can be characterized as stepped walls surrounding voids. Char particles can be produced by plastic deformation due to the compression waves. In some cases, the char particles collapse and spread over to smoother regions and can affect the interface properties of the treatment surface  382  and act as spots for extracting light (i.e., act as microstructures). In some non-limiting examples, the char particles can be as large as 4D v . 
     Each of the above-described characteristics of the plurality of microstructures  384  can enable the phototherapy treatment apparatus  300  to provide a diffuse light profile at the treatment surface  384 .  FIGS.  14  and  15    illustrate one non-limiting example of a more diffuse, or uniform light intensity (or power), profile that can be achieved using the plurality of microstructures  384  of the present disclosure. It should be appreciated that because the plurality of LEDs  368  may not define a continuous light intensity profile along the incident surfaces  386  (i.e., the plurality of LEDs  368  are discretely spaced along the incident surfaces  368 ) a light irradiance profile may substantially vary as a function of position along the treatment surface  382 . 
     Referring to  FIG.  14   ,  FIG.  14    is a graph illustrating a 2D (a cross-sectional) light irradiance profile as a function of longitudinal position along treatment surface  382  without the plurality of microstructures. The peaks in light irradiance correspond with the positions of the plurality of LEDs  368  along the incident surfaces  386 . It should be appreciated that a similar light irradiance profile may exist along the light channel  389  as the light is propagating throughout light channel  389 . 
       FIG.  15    is a graph illustrating a 2D light irradiance profile as a function of longitudinal position along the treatment surface  382  with the addition of the plurality of microstructures  384 . The light irradiance profile of  FIG.  15    is substantially more diffuse, or more uniform, than the light irradiance profile without the plurality of microstructures  384  as illustrated in  FIG.  14   . Thus, the plurality of microstructures  384  act to diffusely distribute the light irradiance from the plurality of LEDs  368  over the treatment surface  382  thereby increasing an integrated light irradiance output by the phototherapy treatment apparatus  300 , which can lead to more efficient phototherapy administration. 
     The graph of  FIG.  15    further illustrates a maximum irradiance and a minimum irradiance output from the treatment surface  382 . An irradiance ratio can be defined as a ratio of the minimum irradiance to the maximum irradiance. The TIR provided by the bed  344  and the diffusion provided by the plurality of microstructures  384  act to maximize the irradiance ratio to ensure the patient receives a substantially uniform, or diffuse, light irradiance over the entire surface area of the treatment surface  382 . Furthermore, it should be appreciated that the irradiance ratio and/or the diffuse profile along the treatment surface  382  can be controlled, for example, by the an angle (taper angle) of the treatment surface  382 , a distance between the treatment surface  382  and the plurality of LEDs  368 , a width of the light channel  389 , a number of the plurality of LEDs  368 , and/or a spacing between the plurality of LEDs  368 . 
       FIG.  16    shows a portion of an absorption spectrum  500  for bilirubin as a function of wavelength and one non-limiting example of an output spectrum  502  for the plurality of LEDs  368 . The output spectrum  502  shows in this non-limiting example that the light emitted from the plurality of LEDs  368  have a center wavelength of approximately 457 nm. In other non-limiting examples, the plurality of LEDs  368  may be configured to output light at a wavelength between approximately 350 nm to approximately 500 nm. It should be appreciated that the treatment of jaundice is but one non-limiting application of the phototherapy treatment apparatus  300  described herein, and the techniques and properties of the disclosed phototherapy treatment apparatus  300  may be applied to a number of phototherapy applications. 
       FIG.  17    is a schematic diagram illustrating one non-limiting example of the phototherapy treatment apparatus  300 . As shown, power can be supplied to the control unit  302  through the input  316  of the bed assembly  304 , which can then be directed through a medical grade power converter  505  to the control unit  302 . In one non-limiting example, the power supplied to the input  316  may be wall power (e.g., 120V AC power). In other non-limiting examples, the input  316  may be configured to receive power from a portable power supply, such as a battery that can be rechargeable via solar energy. 
     A processor  507  of the control unit  302  is in communication with the display  310 , the keypad  312 , an alarm  508 , an indicator  510 , and a cloud  512 . The processor  507  is also in communication with the bed assembly  304 , via control unit  302  through the printed circuit board  354  of the bed assembly  304 . The printed circuit board  354  can receive power relayed from the medical power converter  505  by the control unit  302  to power the LED modules  340  and, specifically, to the plurality of LEDs  368 . The control unit  302  can be configured to control a voltage supplied to the plurality of LEDs  368  to control an intensity of the light emitted onto the incident surfaces  386 , through the light channel  389  and the pad  346  and then to the patient (e.g., a neonate). In some non-limiting examples, the light emitted by the plurality of LEDs  368  may travel through a disposable fabric mattress  514 , as discussed below. 
     The bed assembly  304  may include a temperature sensor  516  (e.g., a thermistor) in communication with the control unit  302  and configured to measure a temperature at one or more locations within the bed assembly  304 . For example, the bed assembly  304  may include a temperature sensor  516  to measure a temperature of the plurality of LEDs  368  and/or at a location adjacent to the patient (e.g., a neonate) to prevent dehydration. The processor  507  can be configured to electrically shut down the phototherapy treatment apparatus  300  if the temperature sensor  516  measured a temperature within the bed assembly  304  that exceeds a predetermined temperature limit. The bed assembly  304  may further include a thermostat  518 , and a plurality of sensors  520  each in communication with the control unit  302 . The thermostat  518  may include a cutoff  522  configured to mechanically cutoff and shut down the phototherapy treatment apparatus  300  if a temperature within the bed assembly  304  exceeds a predetermined temperature limit. The plurality of sensors  520  may be configured to measure one or more of temperature, air flow, voltage, humidity and current. The control unit  302  is also in communication with the fans  342  and configured to selectively instruct the fans  342  to provide air flow throughout the air passageway  394  to aid in the heat dissipation provided by the heat sinks  350 . Each of the temperature sensor  516 , the thermostat  518 , the fans  342 , and the plurality of sensors  520  may also be in communication with the cloud  512  for remote control thereof. 
     Referring now to  FIG.  18   ,  FIG.  18    is a flow chart illustrating one non-limiting example of how the phototherapy treatment apparatus  300  of the present disclosure may operate to treat a patient. At step  600 , a determination is made as to whether a power switch is turned on. If the determination is that the power is not on, no power is supplied to the bed assembly  304  and the control unit  302 , as illustrated at step  604 . If the determination is that the power is on, a self test is performed at step  606 . During the self test, control unit  302  determines at step  608  whether the components of the apparatus are functioning properly (e.g., the LED modules  340 , the temperature sensor  516 , the thermostat  518 , the fans  342 , and/or the sensors  520 ). If the components are not functioning properly, the apparatus can turn off the bed assembly  304 . If the components are functioning properly, then the apparatus continues to an operation mode at step  610 . In the operation mode of step  610 , the apparatus controls an intensity of the light source, at step  612 . For example, the control unit  302  of apparatus  300  may be configured to control a current and/or a voltage supplied to the plurality of LEDs  368  either automatically or in response to a user’s inputs to the keypad  312 . The control unit  302  can receive feedback from the plurality of LEDs  368  to continuously monitor and adjust the output characteristics of the plurality of LEDs  368 . When the control unit  302  provides power to the plurality of LEDs  368 , the plurality of LEDs  368  emit treatment light onto the incident surfaces  386  at a viewing angle that ensures TIR along the light channel  389 . The treatment light then totally internally reflects along the light channel  389  until they contact one or more of the plurality of microstructures  384  of the treatment surface  382 . The plurality of microstructures  384  are configured to disperse the treatment light and diffusely emit the light from the treatment surface  382  to a patient laying on the top side  374 . In the non-limiting example where the plurality of LEDs  368  can be configured to emit light capable of photodissociating bilirubin, the patient can be a jaundiced neonate and the light diffusely emitted from the treatment surface  382  can aid in treating the jaundiced neonate. In other non-limiting examples, the plurality of LEDs  368  may be configured to output light at another wavelength, or range of wavelengths, to treat a patient with an alternative ailment treatable via phototherapy. In some non-limiting examples, the irradiance ratio provided by the bed assembly  304  may be between approximately 0.4 and 0.9. In other non-limiting examples, the irradiance ratio provided by the bed assembly  304  may be greater than approximately 0.4. 
     While in the operation mode, the apparatus can also monitor a temperature (e.g., via temperature sensor  516  and the thermostat  518 ) of the patient and/or the plurality of LEDs  368 , as illustrated at step  614 . The apparatus can determine at step  616  if the temperature(s) measured by the temperature sensor  516  is greater than an allowable limit. If the sensed temperature is not greater than the limit, the apparatus can measure a current consumption of the plurality of LEDs  368  at step  618  and output the current consumption to the display  310  at step  620 . If the sensed temperature is greater than the limit, the apparatus can be configured to trigger an alarm at step  622 . The alarm can be audio, visual and/or tactile. After triggering an alarm at step  622 , the apparatus can re-enter the self test at step  606 . 
       FIG.  19    is a perspective view of another non-limiting example of a phototherapy treatment apparatus  700  of the present disclosure. Phototherapy treatment apparatus  700  includes a bed assembly  702  and a light source  704 , which may or may not include a transition device (not shown). Bed assembly  702  includes an upper bed layer  706  and a lower bed layer  708 , and a thin film  710  located or sandwiched between the layers  706 ,  708 . The upper bed layer  706  includes a peripheral surface  712 , which surrounds a treatment surface  714  containing a plurality of microstructures  716 . The plurality of microstructures  716  can be voids, micro-cracks, chars, combinations therefore, or any other suitable microstructures capable of diffusing light. The microstructures  716  can likewise be formed by CNC machining, laser engraving, sand blasting, chemical engraving, combinations thereof, or other suitable mechanical, chemical, or photic operations. The properties of the microstructures  716  can be similar to the plurality of microstructures  384 , described above. The light source  704  emits light that is transmitted into a light channel (not shown) formed by the bed assembly  702  between the top side  718  of the upper bed layer  706  and the bottom side  720  of the lower bed layer  708 , such that TIR is achieved. The light is dispersed by the microstructures  716  to provide a diffuse intensity profile along the treatment surface  714 . The thin film  710  can be a heat source that is transparent to the light emitted by the light source  704 , allowing the phototherapy treatment apparatus  700  to control temperature of the treatment surface  714 , while providing an evenly diffused amount of light to a patient during treatment. By controlling the temperature of the treatment surface  714 , in this non-limiting example, the phototherapy treatment apparatus  700  could be used to treat both a phototherapy treatable ailment (e.g., jaundice, eczema, atopic dermatitis, vitiligo, psoriasis, seasonal affective disorder, bipolar disorder, wound healing, and inhibiting bacterial growth), and hypothermia. Heat source  714  in one example includes a resistance heater and at least one of a transparent or translucent material. In another non-limiting example, the heat source  714  can be configured to provide heating via another heating mechanism (e.g., chemical, mechanical, conduction, convection, and/or radiation). 
       FIGS.  20  and  21    illustrate two additional non-limiting examples of phototherapy treatment apparatuses of the present disclosure. The apparatuses of  FIGS.  20  and  21    are constructed to include a plurality of unit cells that enhance portability. For example,  FIG.  20    is a perspective view of a phototherapy treatment apparatus  800  in which a bed assembly  802  is separated into a plurality of unit cells constructed as modular pieces  804 , which assemble to form a bed  806 , with a peripheral surface  808  and a treatment surface  810  containing a plurality of microstructures  812 . The properties of the plurality of microstructures  812  can be similar to the plurality of microstructures  384 , described above. The puzzle-like shape of the plurality of modular pieces or unit cells  804  is meant to show one possible method for coupling the plurality of modular pieces  804  together, and is not meant to be limiting. In other non-limiting examples, the modular pieces  804  can be coupled through a variety of mechanical and chemical methods including joints, hinges, adhesives or any other suitable coupling method. The phototherapy treatment apparatus  800  may also include a frame (not shown) capable of containing the plurality of modular pieces  804 , such that the plurality of modular pieces  804  can be arranged within the frame and held in place without direct coupling therebetween. The plurality of modular pieces  804  increase the portability of the apparatus. Again, the plurality of microstructures  812  in this non-limiting example can be voids, micro-cracks, chars, combinations thereof, or any other suitable microstructures capable of diffusing light, and can be formed by CNC machining, laser engraving, sand blasting, chemical engraving, combinations thereof, or any other suitable mechanical, chemical, or photic operations. 
       FIG.  21    is a perspective view of a phototherapy treatment apparatus  900  of the present disclosure in which the plurality of unit cells  904  are connected by a flexible filler material  906 , such that a bed assembly  902  can be folded into a smaller configuration to improve portability. Bed assembly  902  can have a plurality of light sources  908  placed directly below the plurality of unit cells  904 , or can have a single light source  908  placed along an edge of the bed assembly  902  such that the structure of the bed assembly  902  can be completely collapsible. One non-limiting example of a method for collapsing the bed assembly  902  would be to form the plurality of unit cells  904  and the flexible filler material  906  such that the bed assembly  902  is capable of utilizing Origami folding patterns, such as Miura Ori and Ron Resch, to provide effective collapsibility, thereby allowing for increased portability. 
       FIG.  22    is a perspective view of yet another non-limiting example of a phototherapy treatment apparatus  1000  of the present disclosure. In this non-limiting example, the phototherapy treatment apparatus  1000  includes a bed  1002  and a light source  1004 . The bed  1002  contains a plurality of dendrites  1006  or branched tree channels, which form a Litchenberg figure within the bed  1002 . The Litchenberg figure is produced by focusing high voltage at a single point on a surface of the bed  1002 . When a closed path is provided, electrons effectively eat through the material to produce the dendrites  1006 . Similar to the light channels in the previous examples, the dendrites  1006  are capable of efficiently carrying light from the light source  1004  to a treatment surface (not shown), which again would contain a plurality of microstructures (not shown) that would be capable of dispersing light emitted by the light source  1004  to provide a diffuse light intensity along the treatment surface (not shown). 
       FIG.  23    is a perspective view of yet another non-limiting example of a phototherapy treatment apparatus  1100  of the present disclosure. In this non-limiting example, the phototherapy treatment apparatus  1100  includes a bed  1102  and a light apparatus  1104 . The bed  1102  has a top surface  1106 , a bottom surface  1108 , and a plurality of side surfaces  1110 . The top surface  1106  includes a peripheral surface  1112  and a treatment surface  1114 , which includes a plurality of microstructures  1116 . The properties of the plurality of microstructures  1116  can be similar to the plurality of microstructures  384 , described above. The light apparatus  1104  includes a light source  1118  including a transition device (not shown), a heat sink  1020 , and a gooseneck light  1122 , all coupled to a circuit board  1124 . The gooseneck light  1122  can be used in conjunction with the light source  1118  if the light emitted through the treatment surface  1114  is insufficient. Alternatively or additionally, the gooseneck light  1122  can be configured to output infrared heat to the patient. 
       FIG.  24    is a perspective view of a non-limiting example of an optional disposable fabric mattress  514 , which can be used in conjunction with any of the phototherapy treatment apparatuses of the present disclosure. The mattress  514  provides a comfortable surface for a neonate during treatment and confines the neonate within the treatment surface. The mattress  514  includes a porous fabric sheet  1202 , a foam liner  1204 , and a gel pad  1206 . The porous fabric sheet  1202  is at least one of transparent or translucent, antimicrobial, and waterproof. The foam liner  1204  can house beads (not shown), which can aid in the diffusion of light. A gel pad  1206  is configured to support the head of a patient (e.g., a neonate) during treatment. 
     It should be appreciated that the techniques and properties of the phototherapy treatment apparatuses described herein may be applied to other phototherapy applications other than treating a jaundiced neonate. 
     Examples 
     The following examples set forth, in detail, how the phototherapy treatment apparatuses described herein may be used or implemented, and will enable one of skill in the art to more readily understand the principals thereof. The following examples are presented by way of illustration and are not meant to be limiting in any way. 
     Three samples were prepared to simulate a treatment surface including the plurality of microstructures described herein. The three were fabricated from PMMA and were treated using three different kinds of processes: sandblasting, laser etching, and CNC machining. In particular, a first PMMA sample was CNC treated and laser etched, a second PMMA sample was CNC treated and sandblasted, and a third PMMA sample was only CNC treated. The three samples were placed under an optical profilometer (Zygo ZeScope) to capture the surface of the samples in three-dimensions (3D). Images acquired by the profilometer produced two sets of data: point cloud data and image profiles. The point cloud data was post processed to reconstruct the 3D surfaces and to calculate the roughness of the surfaces. 
       FIGS.  25 - 27    show the surface profiles for the three PMMA samples. Specifically,  FIG.  25    shows the surface profile of the first sample that was CNC treated and laser etched,  FIG.  26    shows the surface profile of the second sample that was CNC treated and sandblasted, and  FIG.  27    shows the surface profile of the sample that was only CNC treated. As shown in  FIGS.  25  and  26   , for the laser etched ( FIG.  25   ) and sandblasted ( FIG.  26   ) samples, the surface appears indented, which compliments the shape and size of the projectiles in the respective process. There are not many sharp changes in topography, except for dislocations and chipping. The voids formed by the projectiles appear to be clearer due to the fact that there is a considerably high localized temperature rise at the point of contact. Based on  FIGS.  25  and  26   —which show only minor fluctuations in topography-the directions change of gradient surface normals is more gradual with in a small area, resulting in a more uniform light intensity profile. 
     As shown in  FIG.  27   , for the CNC treated sample, there are small fissures running deep into the surface and can play a major role in trapping light inside the medium. The directions of the surface normals change rapidly within a small neighborhood. In this non-limiting example, the voids formed can be so small they can be considered as cracks. 
     The results of  FIGS.  25 - 27    suggest that only CNC treating a surface (without laser etching or sandblasting) can result in a surface with a higher roughness, which may result in a higher light emittance but a less uniform distribution. To confirm this, the average roughness and average absolute slopes were calculated for each of the three samples tested. The average roughness can be defined as the area between the roughness profile and its mean line, or as the integral of the absolute value of the roughness profile height over the evaluation length. The average roughness, R a , can be defined as: 
     
       
         
           
             
               R 
               a 
             
             = 
             
               1 
               L 
             
             
               
                 
                   ∫ 
                   0 
                   L 
                 
                 
                   
                     
                       r 
                       
                         x 
                       
                     
                   
                   d 
                   x 
                 
               
             
           
         
       
     
      or as: 
     
       
         
           
             
               R 
               a 
             
             = 
             
               1 
               L 
             
             
               
                 ∑ 
                 1 
                 n 
               
               
                 
                   
                     
                       r 
                       n 
                     
                   
                 
                 . 
               
             
           
         
       
     
     Another parameter than can be used to characterize a surfaces roughness is the average absolute slope. The average absolute slope can be defined as the average absolute value of the slope of the roughness profile over the evaluation length. The average absolute slope, Δ a , can be defined as: 
     
       
         
           
             
               Δ 
               a 
             
             = 
             
               1 
               L 
             
             
               
                 
                   ∫ 
                   0 
                   L 
                 
                 
                   
                     
                       
                         
                           d 
                           r 
                           
                             x 
                           
                         
                         
                           d 
                           x 
                         
                       
                     
                   
                   d 
                   x 
                 
               
             
           
         
       
     
      or as: 
     
       
         
           
             
               Δ 
               a 
             
             = 
             
               1 
               L 
             
             
               
                 ∑ 
                 
                   n 
                   − 
                   1 
                 
                 n 
               
               
                 
                   
                     
                       r 
                       
                         n 
                         + 
                         1 
                       
                     
                     − 
                     
                       r 
                       n 
                     
                   
                 
               
             
             . 
           
         
       
     
     The average roughness R a  and the average absolute slope Δ a  can be used to represent the roughness of a surface. It should be appreciated that the average roughness R a  alone may not be sufficient determine if one surface is rougher than another. Surfaces with similar profiles can have similar R a  values. Thus, the average absolute slope parameter is also considered. Table 1 below shows the average roughness R a  and average absolute slope Δ a  values for the three samples of  FIGS.  25 - 27   .  
     
       
         
          TABLE 1
           
               
               
               
               
             
               
                 Sample 
                 Operation 
                 R a  (µm) 
                 Δ a  (no units) 
               
             
            
               
                 
                   FIG.  25 
 
                 
                 CNC+LASER 
                 2.4621 
                 3.44 
               
               
                 
                   FIG.  26 
 
                 
                 CNC+SANDBLAST 
                 2.7286 
                 1.32 
               
               
                 
                   FIG.  27 
 
                 
                 CNC 
                 1.6445 
                 5.82 
               
            
           
         
       
     
     As shown in Table 1, the samples that were CNC treated and laser etched, and CNC treated and sandblasted had a higher average roughness, but the surface that was only CNC treated showed a significantly higher average absolute slope. The light intensity output from the treatment surface  382  can be correlated with the surface roughness, which can be described using R a  and Δ a . Based on the results of Table 1, it would be expected that the sample that was only CNC treated would have a higher output light intensity when compared to the other samples. This hypothesis was tested by measuring a light output intensity profile as a function of position along the treated surfaces in each of the three samples of  FIGS.  25 - 27   . 
       FIGS.  28 - 30    illustrate cross-sectional light profiles as a function of longitudinal position along the samples taken at two different latitudinal positions (one on each side of a center longitudinal axis of the sample). The graph of  FIG.  28    corresponds with the measured light profile of the sample of  FIG.  25   , the graph of  FIG.  29    corresponds with the measured light profile of the sample of  FIG.  26   , and the graph of  FIG.  30    corresponds with the measured light profile of the sample of  FIG.  30   . The light emittance values of  FIGS.  28 - 30    are all normalized by an arbitrary value. As shown in  FIGS.  28 - 30   , the sample that was only CNC treated ( FIGS.  27  and  30   ) indeed output a higher intensity of light than the samples that were laser etched ( FIGS.  25  and  28   ) and sandblasted ( FIGS.  26  and  29   ). In all cases, the light profile output by the samples achieved an irradiance ratio greater than 0.4 over a treatment surface. Thus, the above-described treatment processes (e.g., CNC, laser etching, and sandblasting) can be used to form a plurality of microstructures in the treatment surface and disperse light such that a diffuse light profile is output to a patient. 
     The examples described herein suggest that, in order to achieve the desired light output characteristics (i.e., diffuse profile and an irradiance ratio &gt; 0.4), that the average roughness R a  can be between approximately 1 µm and approximately 20 µm, and the average absolute slope can be between approximately 2 and approximately 15. It should be appreciated that the properties and techniques of the plurality of microstructures described herein may be achieved using alternative manufacturing processes. Also, it should be appreciated that the use of the plurality of microstructures to achieve the desired optical output characteristics may be applied to various phototherapy treatment apparatuses and methods. 
     Thus, while the invention has been described above in connection with particular embodiments and examples, the invention is not necessarily so limited, and numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein.