BACKGROUND OF THE INVENTION

This application claims priority under 35 U.S.C. § 119, based on U.S. Provisional Patent Application No. 62/436,056 filed December 19, 2016, the disclosure of which is hereby incorporated by reference herein.

BACKGROUND

Certain types of medical treatments require that a portion of a human body be held in a same position to facilitate performance of the medical treatment upon that portion of the body. For example, when brain cancer patients undergo radiation treatment, their heads must be maintained in a precise, same location for the treatment such that the underlying position of the brain tumor is fixed in space for the duration of the radiation treatment. Various different techniques have been used in the field of radiation oncology for holding body parts in a fixed position.

BRIEF DESCRIPTION OF THE DRAWINGS FIGs. 1 A and IB depict an inner side view and an outer side view of a thermoplastic mask according to a first exemplary embodiment;

FIGs. 2 A and 2B depict an outer side view and an inner side view of a thermoplastic mask according to a second exemplary embodiment;

FIG. 3 depicts details of an embodiment in which a layer(s) of a coating is adhered to an inner surface of the thermoplastic mask of FIGs. 1A, IB, 2A, or 2B;

FIG. 4 depicts further detail of an embodiment in which a layer(s) of a coating is adhered to an inner surface, and a layer(s) of a coating is also adhered to an outer surface, of the thermoplastic mask of FIGs. 1A, IB, 2A, or 2B;

FIG. 5 depicts an example of the use of a thermoplastic mask for retaining a patient's head in a fixed position upon a treatment table;

FIG. 6 depicts an example of thermoplastic mask 100, of the embodiment depicted in FIGs. 1 A and IB, form fitted in the shape of a patient's face;

FIG. 7 depicts an example of thermoplastic mask 100, of the embodiment depicted in

FIGs. 2A and 2B, form fitted in the shape of a patient's face;

FIG. 8 is a flow diagram that illustrates an exemplary process for adhering one or more coating layers to the sheet of thermoplastic material of the thermoplastic mask of FIGs. 1A, IB, 2A, or 2B; and

FIG. 9 depicts an ultraviolet (UV) adhering process used to bond a coating(s) to the thermoplastic material of the mask of FIGs. 1A, IB, 2A, or 2B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. The following detailed description does not limit the invention.

A technique, in the field of radiation oncology, for holding body parts in a fixed position uses heat-formable structures that include a sheet of retention material that is stretched over the body part of the patient. For example, for performing radiation treatment of a brain tumor, the heat-formable structure includes a mask having a sheet of retention material that is stretched over the patient's face. To form the mask over the patient's face, a hot water bath or oven may be first used to heat the material of the heat-formable structure such that the sheet of material becomes pliable and deformable. If an oven is used to heat the material of the heat-formable structure, then the material may be sprayed with water to hydrate the material prior to application to the patient. The heat-formable mask is then stretched over the patient's face, and the mask is allowed to cool and harden, permanently forming the mask to the shape of the face of the patient. As an example, a mask having a sheet of thermoplastic retention material, after heating, may be stretched over a patient's face, and then allowed to cool. Upon cooling, the mask, formed to the patient's face, creates a structure that can be used to hold the patient's head in a fixed position during radiation treatments. The sheet of retention material used for the heat-formable structure (e.g., mask) may, however, have a surface that is "sticky" relative to the skin of the patient and, therefore, may be difficult to stretch over the skin of the body part of the patient. The sheet of retention material may, when laid upon the face or other body part of the patient, have a tendency to stick or adhere to the skin or hair of the patient. This "stickiness" causes the mask material, that makes contact with the skin or hair, to stretch non-uniformly when the sheet of retention material is stretched over the patient's body part. This non-uniform stretching creates an uneven distribution of mask material, where areas of the mask material that come into contact with skin tend to end up with thicker mask material, and other areas tend to end up with thinner mask material. The uneven distribution of mask material due to the non-uniform stretching may make it more likely that the patient's body part may move during the medical treatment. Exemplary embodiments described herein relate to a thermoplastic mask that includes an extra layer(s) of material that is adhered to at least one surface, of the thermoplastic mask, that is intended to come in contact with the skin (e.g., the face), hair or clothes of the patient. The extra layer(s) of material adhered to the mask may include, for example, a hydrophilic layer (e.g., a hydrophilic polymer), a non-stick layer, an anti-bacterial layer, a hydrophobic layer, a hydrophilic/anti-bacterial combination of layers, and/or a hydrophilic/non-stick combination of layers. In one implementation, the thermoplastic mask may include a sheet of thermoplastic material formed in a mesh pattern that includes a number of holes or openings. The mesh pattern may cover the entirety of the thermoplastic material, or the mesh partem may only cover a certain area or areas of the thermoplastic material. For example, the thermoplastic material may include regions (e.g., bands) that are non-perforated or non- meshed, and other regions (e.g., bands) that are perforated with the mesh partem. The extra layer(s) of material adhered to the sheet of the thermoplastic material may, in one embodiment, be adhered to only a single side of the sheet of thermoplastic material of the mask. In another embodiment, the extra layer(s) of material may be adhered to both sides of the sheet of thermoplastic material of the mask. In an embodiment in which the extra layer(s) is a hydrophilic layer, the hydrophilic layer, after being submerged in a hot water bath or heated in an oven and sprayed with water to hydrate the hydrophilic layer, becomes a wetted, slick surface that does not stick or adhere to skin, hair, or clothes of a patient. The

"slickness," or non-adhesion characteristic, of the hydrophilic layer upon the mask material of the thermoplastic mask enables the mask material, when stretching the mask material over the body part of the patient, to be pulled uniformly over the body part. The uniform pulling of the mask material, enabled by the slickness of the hydrophilic layer, facilitates even distribution of the mask material as it stretches over the patient's body part, preventing the "bunching up" of the mask material and the creation of "thin" and "thick" spots on the final form-fitted mask. Adhering a hydrophilic coating to the mask material, therefore, enables the mask material, when stretched over the patient, to maintain a relatively constant thickness over the entire surface of the thermoplastic mask. A "mask," as referred to herein, includes any structure having thermoplastic material that can be pulled over any body part of a patient to form fit the thermoplastic material to the body part. In some embodiments, a "mask" enables the body part to be immobilized and held in a specific position using a fastening mechanism(s) that may, or may not, be a component of the mask. Thus, a "mask," as used herein, does not refer solely to a structure for placement over a patient's face or head, but includes any type of structure for placement over any body part, or any portion of the body, of a patient (e.g., a structure that pulls over a pelvis of a patient).

FIGs. 1 A and IB depict an inner side view and an outer side view of a thermoplastic mask 100 according to a first exemplary embodiment. As shown in the embodiment of FIGs. 1A and IB, thermoplastic mask 100 may include a mask frame 110, having a length L and width W, that may include a one piece frame that is formed in a shape that includes an inner region in which a sheet of thermoplastic material 120 can be connected to the mask frame 110. In one embodiment, depicted in FIGs. 1A and IB, the shape of mask frame 110 may be a U-shape, where the sheet of thermoplastic material 120 is attached within the inner region of the "U." Other shapes, however, may alternatively used, such as, for example, a rectangular frame having one open side, a square frame having one open side, a triangular frame having one open side, etc. The shape of mask frame 110 may be designed to fit over, or around, a specific body part, or portion of a body, of a patient. Mask frame 110 may be formed from various types of materials, including metal, plastic, carbon fiber, or a composite material.

The sheet of thermoplastic material 120 may include, as shown, a sheet of material formed in a mesh pattern including a number of holes, openings, or perforations.

Thermoplastic material 120 includes a material that is stretchable up to 400% from its original dimensions, such as four times L and four times W, illustrated in FIG. 1A. The shape of the sheet of thermoplastic material 120 may be designed to fit over, or around, a specific body part, or portion of a body, of a patient. The sheet of thermoplastic material 120 may, in one embodiment, be made of polycaprolactone (PCL), or a PCL/polyurethane blend. Other types of thermoplastic material, including other types of polymers, may, however, be alternatively used. The sheet of thermoplastic material 120 may be affixed within the inner region of mask frame 110 using various techniques. For example, the sheet of thermoplastic material 120 may be glued to mask frame 110. As a further example, the sheet of thermoplastic material 120 may be affixed to mask frame 110 using very high heat to melt material 120 such that it bonds with, or adheres to, mask frame 110. As another example, mask frame 110 may include two separate, interlocking pieces that "snap" together. In this example, the edges of the sheet of thermoplastic material 120 are laid between the two interlocking pieces of mask frame 110, and then the two pieces of mask frame 110 are "snapped" together, using fastening mechanisms, to hold the sheet of thermoplastic material 120 stretched tautly in the inner region of mask frame 110. As shown in FIGs. 1A and IB, thermoplastic mask 100 may include retention mounts 130 that permit retention mechanisms (not shown) to be inserted into, and through, the retention mounts such that mask 100 can be fastened to another surface (e.g., the surface of a patient treatment table) or structure to hold the patient's body part in a fixed position relative to the surface or structure.

FIGs. 2A and 2B depict an outer side view and an inner side view of a thermoplastic mask 100 according to a second exemplary embodiment. As shown in the embodiment of FIGs. 2A and 2B, thermoplastic mask 100 may include a mask frame 110 that may include a multi-piece frame that further includes multiple clips 110 to which the sheet of thermoplastic material 120 is connected within an inner region of mask 110 between the multiple clips 110. In one embodiment, depicted in FIGs. 2A and 2B, mask 100 may include three clips 110-1, 110-2, and 110-3, attached to the sheet of thermoplastic material 120 around a perimeter of the sheet of the thermoplastic material 120. For example, each of clips 110-1, 110-2 and 110- 3 may include an L-shaped clip having a clip length Lc that attaches to a different outer edge of the sheet of thermoplastic material 120. In the outer side view of FIG. 2A, the sheet of thermoplastic material 120 has a length LM, on an open side of the sheet, and clips 110-1, 110-2 and 110-3 are fastened to the sheet of material 120 on each of the three other sides of the sheet. As shown, clip 110-1 is fastened to an opposite side of sheet of material 120 (i.e., at a 12 O'clock position) from the open side having length LM. Clip 110-2 is fastened to a side of sheet of material 120 (i.e., at a 9 O'clock position) that is 90 degrees counterclockwise around the outside edge of sheet of material 120 from clip 110-1. Clip 110-3 is fastened to a side of sheet of material 120 (i.e., at a 3 O'clock positionO that is 90 degrees clockwise around the outside edge of sheet of material 120 from clip 110-1. Clips 110-1, 110-2 and 110-3 of the mask frame may be formed from various types of materials, including metal, plastic, carbon fiber, or a composite material.

The sheet of thermoplastic material 120 may include, similar to the embodiment of FIGs. 1 A and IB, a sheet of material that may be formed in a mesh pattern including a number of holes, openings, or perforations. Thermoplastic material 120 includes a material that is stretchable up to 400% from its original dimensions. The sheet of thermoplastic material 120 shown in FIGs. 2A and 2B may, in one embodiment, be made of

polycaprolactone (PCL), or a PCL/polyurethane blend. Other types of thermoplastic material, including other types of polymers, may, however, be alternatively used. Clips 110- 1, 110-2 and 110-3 may be fastened to sheet of material 120 using various fastening mechanisms. For example, clips 110-1, 110-2 and 110-3 may be glued to the sheet of thermoplastic material 120. As a further example, clips 110-1, 110-2, and 110-3 may be fastened to the sheet of thermoplastic material 120 using very high heat to melt material 120 such that it bonds with, or adheres to, clips 110-1, 110-2 and 110-3. As another example, each of clips 110-1, 110-2, and 110-3 may include two separate, interlocking pieces that

"snap" together. In this example, the edges of the sheet of thermoplastic material 120 are laid between the two interlocking pieces of each of clips 110-1, 110-2, and 110-3, and then the two pieces of each of clips 110-1, 110-2 and 110-3 are "snapped" together, using fastening mechanisms, to hold the sheet of thermoplastic material 120 in the inner region between clips 110- 1 , 110-2 and 110-3. In other example, each of clips 110-1, 110-2, and 110-3 may include a clip recess, into which slips an outer edge of the sheet of material 120, and fastening mechanisms of each clip 110 are used to close the clip to affix the edge of the sheet of material 120 within each clip recess.

As further shown in the embodiment of FIGs. 2A and 2B, each of clips 110-1, 110-2 and 110-3 of thermoplastic mask 100 may include respective retention mounts 210-1, 210-2, and 210-3 that permit retention mechanisms (not shown) to be inserted into, and through, the retention mounts such that the clips 110 of mask 100 can be fastened to another surface (e.g., the surface of a patient treatment table) or structure to hold the patient's body part in a fixed position relative to the surface or structure.

FIGs. 1 A and IB have depicted a first exemplary embodiment in which a one-piece frame 110 may be used to connect to the sheet of thermoplastic material 120 and to act as a fastening mechanism for fastening the frame 110 to another structure (e.g., to a treatment table). FIGs. 2A and 2B have depicted a second exemplary embodiment in which a multi- piece frame, that includes multiple clips, may be used to connect to the sheet of thermoplastic material 120, and to act as a fastening mechanism for fastening the clips of the frame 110 to another structure. In other embodiments, however, a different type of fastening mechanism, other than a frame, may be used for fastening the sheet of thermoplastic material 120 of the mask 100 to another structure. For example, the mask 100 may, instead of a frame 110, have retention holes (i.e., holes through the thermoplastic material) disposed around an outer perimeter of the sheet of thermoplastic material. External retention means may be inserted through these retention holes to cause the sheet of thermoplastic material to be fastened to another structure (e.g., a treatment table).

FIG. 3 depicts further detail of an embodiment in which a layer(s) 300 of a coating is adhered to an inner surface (i.e., the surface intended to come in contact with the patient's skin) of the sheet of material 120 of thermoplastic mask 100. FIG. 3 may depict details of the sheet of thermoplastic material 120 depicted in either of the embodiments of FIGs. 1A and IB, or FIGs. 2A and 2B. In this embodiment, the sheet of thermoplastic material 120 is formed to a thickness Tmask that ranges from about 1.5millimeters (mm) to about 5.0 mm. As further shown, the layer(s) 300 of the coating adhered to the sheet of thermoplastic material 120 is formed in a thickness Tcoaung-mner that ranges from about 0.01mm to about 0.10 mm. The layer(s) 300 of the coating adhered to the sheet of thermoplastic material 120 may include a hydrophilic layer (e.g., a hydrophilic polymer layer), a non-stick layer (also referred to as a non-adhesion layer), an anti-bacterial layer, a hydrophobic layer, a hydrophilic/anti- bacterial combination of layers, and/or a hydrophilic/non-stick combination of layers. The layer(s) 300 adhered to the sheet of thermoplastic material 120 may have one or more of the following properties: 1) the layer(s) 300 bonds well with the particular thermoplastic material 120 of mask 100; 2) the layer(s) 300, after bonding with the thermoplastic material 120 of mask 100, endures the heat and temperature of the hot water bath or oven used to form fit the mask to the body part of the patient without becoming un-bonded or otherwise changing the properties of the layer(s) 300; 3) the layer(s) 300 is applied using a bonding/curing process that does not damage the underlying thermoplastic material 120 of mask 100; and 4) the layer(s) 300 must be stretchable up to 400% (e.g., from its original size) such that the coating stretches along with the thermoplastic material 120 when it is stretched over the patient's body part. In one embodiment, the layer(s) 300 adhered to the sheet of thermoplastic material 120 will have all of the properties 1), 2), 3), and 4) listed above. The hydrophilic polymer layer may include, for example, a ComfortCoat™ hydrophilic coating manufactured by DSM™, or Lubricent™ hydrophilic coating manufactured by Hartland™. In one embodiment, the hydrophilic polymer layer may include a photo-reactive hydrophilic polymer, such as, for example, ISurGlide™ 460 manufactured by ISurTec™. The non-stick or non-adhesion layer may include, for example, a Teflon™ coating manufactured by Slipmate™ The anti-bacterial layer may include, for example, Bacticent™ anti-microbial coating manufactured by Hartland™. The hydrophobic layer may include, for example, a NeverWet™ hydrophobic coating manufactured by Rust-oleum™, or a ISurGuard™ hydrophobic coating manufactured by ISurTec™. Other types of hydrophilic polymers, nonstick coatings, anti-microbial coatings, and hydrophobic coatings, not described above, may alternatively be used. The bonding/curing process used to adhere the layer(s) 300 to the thermoplastic material 120 may include, for example, using heat to bond the layer(s) 300, using moisture to bond the layer(s) 300, and/or using ultraviolet (UV) light to bond the layer(s) 300.

FIG. 4 depicts further detail of an embodiment in which a layer(s) 400 of a coating is adhered to an inner surface (i.e., the surface intended to come in contact with skin) of the sheet of material 120 of thermoplastic mask 100 and a layer(s) 410 of a coating is also adhered to an outer surface of the sheet of material 120 of thermoplastic mask 100. FIG. 4 may depict details of the sheet of thermoplastic material 120 depicted in either of the embodiments of FIGs. 1A and IB, or FIGs. 2A and 2B. In this embodiment, the sheet of thermoplastic material 120 is formed to a thickness T _mas k that ranges from about

1.5 millimeters (mm) to about 5.0 mm. As further shown, the layer(s) 400 of the coating adhered to the inner surface of the sheet of thermoplastic material 120 is formed to a thickness T coating-inner that ranges from about 0.01mm to about 0.10 mm. As also shown, the layer(s) 410 of the coating adhered to the outer surface of the sheet of thermoplastic material 120 is formed to a thickness T coating-outer that ranges from about 0.01mm to about 0.10 mm. In the embodiment of FIG. 4, both of layer(s) 400 and 410 may include a hydrophilic coating, a non-stick coating, an anti-bacterial coating, a hydrophobic coating, and/or a combination hydrophilic coating with an anti-bacterial coating. The specific types of the hydrophilic, nonstick, anti -bacterial, or hydrophobic layers for each of layers 400 and 410 are the same as, or similar to, those described with respect to layer 300 in FIG. 3 above. The properties of the layer(s) adhered to the sheet of thermoplastic material 120 are the same as, or similar to, those described with respect to FIG. 3.

FIG. 5 depicts an example of the use of a thermoplastic mask 100 for retaining a patient's head in a fixed position upon a treatment table. In the example of FIG. 5, a patient 500 is positioned upon a treatment table 510, such as a treatment table associated with a radiation therapy system. The thermoplastic mask 100 may be placed in a hot water bath having water heated to an appropriate temperature for heat forming the thermoplastic mask 100. Alternatively, the thermoplastic mask 100 may be placed in an oven to heat the mask 100 to the appropriate temperature for heat forming the thermoplastic mask 100. Upon the proper positioning of patient 500, the thermoplastic mask 100 may be removed from the hot water bath, placed over a top of patient 500's face, and then the mask 100 is stretched downwards such that the stretchable material 120 of mask 100 stretches to form fit to patient 500's face. If the mask 100 is heated in an oven instead of a hot water bath, upon the proper positioning of patient 500, the thermoplastic mask 100 may be removed from the oven, sprayed with water to hydrate the surface(s) of the mask 100, placed over a top of patient 500's face, and then the mask 100 is stretched downwards such that the stretchable material 120 of mask 100 stretches to form fit to patient 500's face. The thermoplastic mask 100 may be stretched downwards until the mask frame 110 contacts the treatment table 510 beneath the patient 500 (such that the mask 100 may be fastened to table 510, with fastening mechanisms, during subsequent radiation treatment). If the mask material 120 of the mask 100 is coated with a layer of hydrophilic polymer, the hydrophilic polymer layer becomes wetted due to submersion in the hot water bath, or wetted due to spraying with water subsequent to removal from the oven, resulting in a slick surface that has less drag when coming into contact with skin, clothes, and hair of the patient. The "slick" nature, or non- adhesion property, of the wetted hydrophilic polymer coating causes a more uniform

"pulling" of the mask material 120, when the mask 100 is stretched downward over the patient's face, such that the mask material 120 can be stretched uniformly over the entire sheet of mask material 120. After form-fitting mask 100 to patient 500's face, the mask 100 is permitted to cool and harden such that the sheet of material 120 of mask 100 retains the form-fitted shape of the patient 500's face.

FIG. 6 depicts an example of thermoplastic mask 100, of the embodiment depicted in FIGs. 1 A and IB which includes the U-shaped mask frame 110, form fitted in the shape of the patient 500's face, subsequent to the forming process described with respect to FIG. 5. The form fitted mask 100 may subsequently be used, and re-used, for retaining the same patient 500's head in a fixed position during radiation or other treatments.

FIG. 7 depicts an example of thermoplastic mask 100, of the embodiment depicted in FIGs. 2 A and 2B in which the mask frame includes multiple clips, form fitted in the shape of the patient's face, subsequent to a forming process that is similar to that described above with respect to FIG. 5. The form fitted mask 100 may subsequently be used, and re-used, for retaining the same patient's head in a fixed position during radiation or other treatments.

FIG. 8 is a flow diagram that illustrates an exemplary process for adhering one or more layers to the sheet of thermoplastic material 120 of thermoplastic mask 100. The exemplary process of FIG. 8 is described below with reference to the example depicted in FIG. 9.

The exemplary process may include applying a layer(s) of coating to a first side of the thermoplastic mask material 120 (block 800). Various techniques may be used for applying the layer(s) of coating to the first side of mask material 120, including brushing the coating on, spraying the coating on, pouring the coating on, etc. The first side of mask material 120 may be the side of the material that is intended to contact the skin when the mask 100 is used for medical procedures. The layer(s) of the coating may include a hydrophilic layer (e.g., a hydrophilic polymer layer), a non-stick layer, an anti-bacterial layer, a hydrophobic layer, a hydrophilic/anti-bacterial combination of layers, and/or a hydrophilic/non-stick combination of layers, as discussed above.

An adhering process is performed to bond the coating(s), applied in block 800, to the sheet of thermoplastic material 120 (block 810). Various types of adhering processes may be used for bonding the coating(s) to the thermoplastic material 120. In an exemplary embodiment, depicted in FIG. 9, a UV adhering process is used to bond the coating(s) to the thermoplastic material 120 of mask 100. The coating, in this example, may be a layer of photo-reactive hydrophilic polymer. As shown in FIG. 9, after the layer(s) 900 of coating is applied to the sheet of mask material 120, a UV light source 910 (e.g., within a UV oven) generates UV lighting at, for example, 254 nm wavelength, and directs the UV lighting upon the layer(s) 900 of coating for approximately 3 minutes to cause layer(s) 700 to bond to the mask material 120. It should be understood that other UV light sources, having different wavelengths and different durations, may be used based on the particular material of layer(s) 900.

The sheet of thermoplastic material 120 is fitted to the frame 110 of the mask 100

(block 820). Various different techniques, as already described above with respect to the embodiments of FIGs. 1A and IB, and FIGs. 2A and 2B, may be used for fitting the sheet of thermoplastic material 120 to frame 110 of mask 100, including using glue, or the application of heat to melt material 120 to bond with mask frame 110. In other embodiments, the sheet of thermoplastic material 120 can be fitted to the frame 110 by mask frame 110 having two separate, interlocking pieces that "snap" together. In this embodiment, the edges of the sheet of thermoplastic material 120 are laid between the two interlocking pieces of mask frame 110, and then the two pieces of mask frame 110 are "snapped" together, using fastening mechanisms, to hold the sheet of thermoplastic material 120 stretched tautly in the inner region of mask frame 110.

Blocks 800 and 810 apply a layer(s) of coating to a first side of thermoplastic material 120 and adhere the coating to the material 120. Referring to mask 100 as depicted in FIG. 1A, the "first side" corresponds to the upper surface of the sheet of mask material 120 shown. Referring to mask 100 depicted in FIG. 2B, the "first side" corresponds to the upper surface of the sheet of mask material 120 shown. A similar process may be used to apply a layer(s) of coating to a second side of thermoplastic material 120 (i.e., the opposite side to layer 900 shown in FIG. 9). Referring to mask 100 depicted in FIG. IB, the "second side" corresponds to the upper surface of the sheet of mask material 120 shown, which would correspond to the lower surface illustrated in FIG. 1A. Referring to mask 100 depicted in FIG. 2A, the "second side" corresponds to the upper surface of the sheet of mask material 120 shown, which would correspond to the lower surface illustrated in FIG. 2B. Blocks 800 and 810 may, thus, be performed a second time to apply a layer(s) of coating to the second side of thermoplastic material 120.

The foregoing description of implementations provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. For example, while series of blocks have been described with respect to FIG. 8 the order of the blocks may be varied in other implementations. Moreover, non-dependent blocks may be performed in parallel.

Although the invention has been described in detail above, it is expressly understood that it will be apparent to persons skilled in the relevant art that the invention may be modified without departing from the spirit of the invention. Various changes of form, design, or arrangement may be made to the invention without departing from the spirit and scope of the invention. Therefore, the above-mentioned description is to be considered exemplary, rather than limiting, and the true scope of the invention is that defined in the following claims.

No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article "a" is intended to include one or more items. Further, the phrase "based on" is intended to mean "based, at least in part, on" unless explicitly stated otherwise.