阅读说明：本技术 利用不对称反射屏的双屏数字射线造影 (Dual screen digital radiography with asymmetric reflective screens ) 是由 安东尼·鲁宾斯基 W.赵 约翰·A·罗兰兹 于 2018-08-02 设计创作，主要内容包括：本发明涉及一种用于检测辐射的结构。所述结构可以包括具有第一厚度的第一屏幕和具有大于所述第一厚度的第二厚度的第二屏幕。所述结构还可以包括布置在所述第一屏幕和所述第二屏幕之间的光传感器阵列。所述第一屏幕的背侧可以面对朝向所述结构入射的入射辐射。所述第一屏幕可以包括第一反射层,所述第一反射层可以将在所述第一屏幕中散射的光子朝向所述光传感器阵列反射。所述第二屏幕可以面对所述光传感器阵列,使得所述第一屏幕和所述第二屏幕被定向在相反方向上。所述第二屏幕可以包括第二反射层,所述第二反射层可以将穿过所述光传感器阵列的光子朝向所述光传感器阵列反射。(The present invention relates to a structure for detecting radiation. The structure may include a first screen having a first thickness and a second screen having a second thickness greater than the first thickness. The structure may further include a photosensor array disposed between the first screen and the second screen. The back side of the first screen may face incident radiation incident towards the structure. The first screen may include a first reflective layer, which may reflect photons scattered in the first screen toward the photosensor array. The second screen may face the photosensor array such that the first screen and the second screen are oriented in opposite directions. The second screen may include a second reflective layer that may reflect photons that pass through the photosensor array toward the photosensor array.)

1. A structure, comprising:

a first screen having a first thickness;

a second screen having a second thickness greater than the first thickness;

a photosensor array disposed between the first screen and the second screen,

wherein the first screen is oriented to face the photosensor array such that a back side of the first screen faces incident radiation incident toward the structure, and the first screen comprises:

a first fluorescent layer that converts the incident radiation incident on the structure into photons;

a first reflective layer disposed on the back side of the first screen, wherein the first reflective layer reflects the photons scattered in the first fluorescent layer toward the photosensor array,

wherein the second screen is oriented to face the photosensor array such that the first screen and the second screen are oriented in opposite directions, the second screen comprising:

a second fluorescent layer;

a second reflective layer disposed on a backside of the second screen, wherein the second reflective layer reflects the photons passing through the photosensor array toward the photosensor array, and

wherein the photosensor array is to capture the photons and convert the captured photons to electrical signals.

2. The structure of claim 1, wherein the photosensor array comprises a photosensitive storage element comprising a plurality of switching elements.

3. The structure of claim 1, further comprising a substrate disposed between the photosensitive array and the second fluorescent layer.

4. The structure of claim 3, wherein the substrate is one of glass, plastic, and cellulose.

5. The structure of claim 1, further comprising a fiber optic plate disposed between the photosensitive array and the second phosphor layer.

6. The structure of claim 1, wherein a ratio of the first thickness to the second thickness maximizes quantum detection efficiency of an imaging system utilizing the structure.

7. The structure of claim 1, wherein a ratio of the first thickness to the second thickness maximizes a modulation transfer function of an imaging system utilizing the structure.

8. An imaging system, comprising:

a processor configured to communicate with a fabric, the fabric comprising:

a first screen having a first thickness;

a second screen having a second thickness greater than the first thickness;

a photosensor array disposed between the first screen and the second screen,

wherein the first screen is oriented to face the photosensor array such that a back side of the first screen faces incident radiation incident toward the structure, and the first screen comprises:

a first fluorescent layer that converts the incident radiation incident on the structure into photons;

a first reflective layer disposed on the back side of the first screen, wherein the first reflective layer reflects the photons scattered in the first fluorescent layer toward the photosensor array,

wherein the second screen is oriented to face the photosensor array such that the first screen and the second screen are oriented in opposite directions, the second screen comprising:

a second fluorescent layer;

a second reflective layer disposed on a backside of the second screen, wherein the second reflective layer reflects the photons passing through the photosensor array toward the photosensor array, and

wherein the photosensor array is to capture the photons and convert the captured photons to electrical signals,

the processor is configured to:

receiving the electrical signal from the structure; and is

An image is generated using the electrical signals.

9. The imaging system of claim 8, wherein the photosensor array comprises a photosensitive storage element comprising a plurality of switching elements.

10. The imaging system of claim 8, wherein the structure further comprises a substrate disposed between the photosensitive array and the second fluorescent layer.

11. The imaging system of claim 10, wherein the substrate is one of glass, plastic, and cellulose.

12. The imaging system of claim 8, wherein the structure further comprises a fiber optic plate disposed between the photosensitive array and the second phosphor layer.

13. The imaging system of claim 8, wherein a ratio of the first thickness to the second thickness maximizes a quantum detection efficiency of the imaging system.

14. The imaging system of claim 8, wherein a ratio of the first thickness to the second thickness maximizes a modulation transfer function of the imaging system.

15. An apparatus, comprising:

a radiation detector;

an X-ray source for irradiating X-rays to an object arranged between the X-ray source and the radiation detector, the radiation detector comprising:

a first screen having a first thickness;

a second screen having a second thickness greater than the first thickness;

a photosensor array disposed between the first screen and the second screen,

wherein the first screen is oriented to face the photosensor array such that a back side of the first screen faces the X-rays incident toward the radiation detector, and the first screen includes:

a first fluorescent layer that converts the X-rays to photons;

a first reflective layer disposed on the back side of the first screen, wherein the first reflective layer reflects the photons scattered in the first fluorescent layer toward the photosensor array,

wherein the second screen is oriented to face the photosensor array such that the first screen and the second screen are oriented in opposite directions, the second screen comprising:

a second fluorescent layer;

a second reflective layer disposed on a backside of the second screen, wherein the second reflective layer reflects the photons passing through the photosensor array toward the photosensor array, and

wherein the photosensor array is to capture the photons and convert the captured photons to electrical signals,

a processor to:

receiving the electrical signal from the radiation detector;

generating an image of the object using the electrical signals.

16. The apparatus of claim 15, wherein the photosensor array comprises a photosensitive storage element comprising a plurality of switching elements.

17. The apparatus of claim 15, wherein the structure further comprises a substrate disposed between the photosensitive array and the second fluorescent layer.

18. The apparatus of claim 15, wherein the structure further comprises a fiber optic plate disposed between the photosensitive array and the second phosphor layer.

19. The apparatus of claim 15, wherein a ratio of the first thickness to the second thickness maximizes a quantum detection efficiency of the imaging system.

20. The apparatus of claim 15, wherein the arrangement of the first thickness and the second thickness maximizes a modulation transfer function of the imaging system.

Technical Field

The present application relates generally to radiation detectors and digital radiography.

Background

In digital radiography, an imaging system may include a screen that absorbs radiation and generates light, where the generated light is sensed by a photosensor array to produce an electrical signal. The generated electrical signals may be used by an imaging system to generate a digital image. In some examples, the quality (e.g., sharpness, resolution) of the resulting image may be affected by various phenomena such as light scattering and/or other phenomena.

Disclosure of Invention

In some examples, structures in digital radiography applications are generally illustrated. The structure may include a first screen having a first thickness and a second screen having a second thickness greater than the first thickness. The structure may also include a photosensor array disposed between the first screen and the second screen. The first screen may be oriented to face the photosensor array such that a back side of the first screen faces incident radiation incident toward the structure. The first screen may include a first phosphor layer that converts incident radiation incident on the structure into photons. The first screen may further include a first reflective layer disposed on a backside of the first screen. The first reflective layer may reflect photons scattered in the first fluorescent layer toward the photosensor array. The second screen may be oriented to face the photosensor array such that the first screen and the second screen are oriented in opposite directions. The second screen may include a second fluorescent layer. The second screen may further include a second reflective layer disposed on a backside of the second screen. The second reflective layer may reflect photons that pass through the photosensor array towards the photosensor array. The photosensor array can be used to capture photons and convert the captured photons into electrical signals.

In some examples, an imaging system is generally described. The imaging system may include a processor configured to communicate with the structure. The structure may include a first screen having a first thickness and a second screen having a second thickness greater than the first thickness. The structure may also include a photosensor array disposed between the first screen and the second screen. The first screen may be oriented to face the photosensor array such that a back side of the first screen faces incident radiation incident toward the structure. The first screen may include a first phosphor layer that converts incident radiation incident on the structure into photons. The first screen may include a first reflective layer disposed on a back side of the first screen. The first reflective layer may reflect photons scattered in the first fluorescent layer toward the photosensor array. The second screen may be oriented to face the photosensor array such that the first screen and the second screen are oriented in opposite directions. The second screen may include a second fluorescent layer. The second screen may further include a second reflective layer disposed on a backside of the second screen. The second reflective layer may reflect photons that pass through the photosensor array towards the photosensor array. The photosensor array can be used to capture photons and convert the captured photons into electrical signals. The processor may be configured to receive the electrical signals from the structure and to generate an image using the electrical signals.

In some examples, an X-ray device is generally illustrated. The apparatus may include a radiation detector, an X-ray source, and a processor. The X-ray source may be used for irradiating X-rays to an object arranged between the X-ray source and the radiation detector. The radiation detector may include a first screen having a first thickness and a second screen having a second thickness greater than the first thickness. The radiation detector may further comprise a photosensor array arranged between the first screen and the second screen. The first screen may be oriented to face the photosensor array such that a backside of the first screen faces X-rays impinging toward the radiation detector. The first screen may include a first phosphor layer that converts X-rays to photons. The first screen also includes a first reflective layer disposed on a back side of the first screen. The first reflective layer may reflect photons scattered in the first fluorescent layer toward the photosensor array. The second screen may be oriented to face the photosensor array such that the first screen and the second screen are oriented in opposite directions. The second screen may include a second fluorescent layer. The second screen may further include a second reflective layer disposed on a backside of the second screen. The second reflective layer may reflect photons that pass through the photosensor array towards the photosensor array. The photosensor array can be used to capture photons and convert the captured photons into electrical signals. A processor may be used to receive the electrical signals from the radiation detector and to generate an image of the object using the electrical signals.

Further features as well as the structure and operation of various embodiments are described in detail with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.

Drawings

FIG. 1 illustrates an example structure that may be used to implement dual-screen digital radiography utilizing an asymmetric reflective screen in one embodiment.

FIG. 2 illustrates an example structure that may be used to implement dual-screen digital radiography using an asymmetric reflective screen in one embodiment.

FIG. 3 illustrates exemplary results of performance metrics associated with two-screen digital radiography utilizing an asymmetric reflective screen in one embodiment.

FIG. 4 illustrates exemplary results of performance metrics associated with two-screen digital radiography utilizing an asymmetric reflective screen in one embodiment.

Fig. 5 illustrates the difference between the standard configuration of an X-ray detector and the dual screen configuration described in this disclosure.

Fig. 6 shows experimental results demonstrating MTF differences between a standard or conventional configuration with one screen and the dual screen configuration described in the present disclosure.

Fig. 7 shows experimental results demonstrating DQE differences between a standard or conventional configuration with one screen and the dual screen configuration described in the present disclosure.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In describing the present invention, descriptions of related functions or configurations known in the art are omitted for clarity of understanding of the concept of the present invention, so as not to obscure the present invention with unnecessary detail.

An active-matrix indirect flat-panel imager (AMFPI) may be used in digital radiography applications. In some examples, the AMFPI may include a single-sided intensifying screen (single-sided intensifying screen), and may be manufactured as follows: an array of sensors (e.g., an array of thin film transistors) is placed below the intensifying screen so that the AMFPI can operate by making X-rays incident from above the intensifying screen. The thickness of the single-sided intensifying screen can be based on a trade-off between X-ray absorption and spatial resolution. For example, increasing the thickness may increase absorption and sensitivity, but may also decrease resolution due to scattering of light in the phosphor layer of the intensifying screen.

In screen-film radiography, a dual-screen system may include a dual-emulsion film (dual-emulsion film) disposed between two partitions divided from a single-sided intensifying screen. This configuration may reduce light scattering caused by the shortened distance between the incident radiation and the film, but may cause crossover phenomena where photons may penetrate the film emulsion and then reflect from the opposite partition.

For further explanation below, an architecture according to the present disclosure (e.g., architecture 100 shown in fig. 1) may address some of the shortcomings of various digital radiography systems and film-screen radiography systems.

Fig. 1 illustrates an example structure 100 for implementing dual-screen digital radiography with an asymmetric reflective screen that may be arranged in accordance with at least some embodiments described herein. The structure 100 may include a first screen 110, a second screen 120, a photosensor array 105, and a substrate 107. First screen 110 may be oriented such that a backside of the first screen faces incident radiation, such as incident X-rays 102, incident toward structure 100. The photosensor array 105 can be disposed between the first screen 110 and the second screen 120. The first screen 110 and the second screen 120 may be oriented in opposite directions such that the first screen 110 and the second screen 120 face each other. In the orientation of the structure 100 shown in fig. 1, the back side of the first screen 110 can be the top surface of the structure 100, and the back side of the second screen 120 can be the bottom surface of the structure 100. The thickness of the first screen 110 may be less than the thickness of the second screen 120. The first screen 110 may be disposed above the photosensor array 105 such that the incident X-rays 102 may be incident on the first screen 110. In some examples, the first screen 110 may be disposed above the photosensor array 105 because the thickness of the first screen 110 is less than the thickness of the second screen 120.

The screen 110 may include a scintillating phosphor layer 114 and a reflective layer 112, wherein the reflective layer 114 may be made of a highly reflective material. The screen 120 may include a scintillating phosphor layer 122 and a reflective layer 124, wherein the reflective layer 124 may be made of a highly reflective material. For example, the reflective layers 114, 124 may be coated with a layer of white material such as titanium dioxide. The reflective layers 114, 124 may be of the same or different dimensions and may be coated with the same or different materials. Both phosphor layers 114, 124 may include a phosphor crystal that may capture incident X-rays 102 and convert the captured X-rays into photons. In some examples, the thickness of phosphor layer 114 may be less than the thickness of phosphor layer 124, such that screen 110 may be thinner than screen 120. In some examples, both screens 110, 120 may be particle type (e.g., Gd02S2: Tb) or pillar type (e.g., CsI: TI) or a combination of both. In some examples, additional supports for thicker screens (e.g., screen 120) may optionally be disposed below reflective layer 122 to increase structural stability.

The photosensor array 105 can include a photosensitive storage element 108, which can include a plurality of switching elements 106. Substrate 107 may have a small optical thickness and may be disposed between photosensor array 105 and fluorescent layer 124. The photosensitive memory element 108 and the switching element 106 may be arranged on top of the substrate 107. The photosensor array 105 may be a-Si: H n-i-p photodiodes, MIS type, or other types. The photosensor array 105 may be sensitive to light incident from either side and may have low transmittance at wavelengths emitted by the screens 110, 120. For example, the photosensor array 105 can have a high optical absorption (90% or more) at the wavelength of the light emitted by the screens 110, 120, such that pixel cross-talk and cross-effects can be reduced. In one example, the substrate 107 may be thin glass, plastic, or cellulose with a thickness of less than 30 microns, and preferably less than 10 microns. The photosensor array 105 can capture photons and can convert the captured photons into electrical signals, which can be used by a device (separate from the structure 100) to produce a digital image. For example, each switching element 106 may correspond to an image such that a set of pixel values may be read by switching a particular column, row, or group of pixels to generate an image.

In one example, the structure 100 may be a component of an imaging system that produces an image. In operation, the phosphor layer 114 can receive incident X-rays 102 and convert the incident X-rays 102 into light. When the converted light reaches the photosensor array 105, the photosensor array 105 may capture photons from the converted light and may convert the photons to electrical signals. In the example shown in FIG. 1, when incident X-rays 102 reach fluorescent layer 114, crystals in fluorescent layer 114 may convert the X-rays to photons 140. Photons 140 may scatter in phosphor layer 114. Some scattered photons may be incident towards the photosensor array 105, while other scattered photons may be distant from the photosensor array 105. Reflective layer 112 may reflect the scattered photons toward photosensor array 105 so that photosensor array 105 captures the scattered photons.

In some examples, incident X-rays 102 may not be fully captured by fluorescent layer 114 (e.g., fluorescent layer 114 may not have enough crystals to convert all incident X-rays). Uncaptured X-rays may pass through photosensor array 105 and crystals in fluorescent layer 124 of second screen 120 may convert the captured X-rays to photons 150. Photons 150 may scatter in phosphor layer 124. Some scattered photons may be incident towards the photosensor array 105, while other scattered photons may be distant from the photosensor array 105. Reflective layer 122 may reflect the scattered photons toward photosensor array 105 so that photosensor array 105 captures the scattered photons. Thus, second screen 120 facilitates light sensor array 105 to recapture photons from reflections off of screen 110 that are not absorbed by light sensor array 105.

In some examples, the light converted from the top screen 110 (facing the incident X-rays) may be weighted by adjusting the optical characteristics of the photosensor array 105. Light from the screen 110 may include more information from the low energy portion of the incident X-ray spectrum due to beam hardening effects (beam hardening effects), and the emphasis on this may improve the visibility of low contrast objects in images generated by imaging systems utilizing the structure 100.

In one example, the process may be implemented by a computer device or hardware processor to construct the structure 100, and may begin with performing a radiographic inspection to determine beam quality or half-value layers (HV L: half-value layers) of the phosphor layers 114, 124.

For example, the thicknesses of the two scintillating phosphor layers 114, 124 can be selected to maximize the quantum detection efficiency (DQE: destructive quadrature efficiency) of an imaging system utilizing structure 100 DQE is the output signal-to-noise ratio (SNR) per input quantum, and DQE depends on spatial frequency and X-ray exposure the fundamental limits of DQE performance are given by the product of X-ray absorption efficiency and two noise factors, where one noise factor quantifies the change in magnitude of response to an absorption event (Swank factor) and one noise factor quantifies the change in spatial response to an event (Lubberts factor (L ubberts factor)) that describes the reduction in DQE resulting from X-ray absorption events occurring at different distances from the photosensor array.

In some examples, the thicknesses of the two scintillating phosphor layers 114, 124 can be selected to maximize the MTF of an imaging system utilizing structure 100. To maximize the MTF, the thinner of the two scintillation screens can be chosen to be between 20% and 40% of the total scintillation layer thickness.

In one example, the structure 100 may be a component of an imaging system. The imaging system may include a structure 100, a processor, and a memory in communication with each other. The first screen 110 of the structure 100 may receive incident X-rays 102 and may convert the incident X-rays to photons. The reflective layer 114 may reflect photons scattered in the first fluorescent layer 112 towards the photosensor array 105. The reflective layer 124 of the second screen 120 may reflect photons that pass through the photosensor array 105 back to the photosensor array 105. The photosensor array 105 can convert the captured photons to electrical signals and can output the electrical signals to a processor. The processor may store the electrical signals in the memory and may use the electrical signals to generate an image.

In one example, the structure 100 may be a radiation detector in an apparatus that includes an X-ray source and a processor. The X-ray source may be an X-ray tube that generates X-rays, or other device that can produce X-rays. An object, such as an object, may be disposed between the X-ray source and the structure 100. The X-ray source may irradiate X-rays onto the object, wherein the object may absorb a portion of the X-rays, resulting in attenuation of the X-rays. The attenuated X-rays may be incident toward the structure 100 as incident X-rays 102. The first screen 110 of the structure 100 may receive incident X-rays 102 and may convert the incident X-rays to photons. The reflective layer 114 may reflect photons scattered in the first fluorescent layer 112 towards the photosensor array 105. The reflective layer 124 of the second screen 120 may reflect photons that pass through the photosensor array 105 back to the photosensor array 105. The photosensor array 105 can capture photons and convert the captured photons into electrical signals. A processor may be used to receive the electrical signals from the radiation detector and to generate an image of the object using the electrical signals.

Fig. 2 illustrates an example structure 200 that may be used to implement dual-screen digital radiography utilizing asymmetric reflective screens, arranged in accordance with at least some embodiments described herein. Fig. 2 may be described below with reference to the above description of fig. 1.

The structure 200 may include a first screen 110, a second screen 120, a photosensor array 205, and a fiber optic plate 202. The photosensor array 205 can include a photosensitive storage element 108, which can include a plurality of switching elements 106. The fiber optic plate 202 may have an optical thickness of substantially 0, such as a negligible optical thickness and a physical thickness of 1 to 3 mm. In some examples, the fiber numerical aperture of the fiber optic plate 202 may be relatively large.

Fig. 3 illustrates example results of performance metrics related to dual-screen digital radiography using asymmetric reflective screens, arranged in accordance with at least some embodiments described herein. Fig. 3 may be described below with reference to the above description of fig. 2.

Fig. 3 shows a graph 302, the graph 302 representing the roberts factor and DQE for an imaging system utilizing a dual screen structure (e.g., structures 100 and/or 200) with a white backing (reflective layers 112, 122) and a resolution of 5lp/mm (line pairs/mm). In graph 302, the total thickness of the two screens in the dual screen configuration is 160 microns (0.160mm), with the back side of the thinner screen (first screen 110) (the side including reflective layer 112) at 0 microns and the back side of the thicker screen (the side including reflective layer 114) at 160 microns. As shown in graph 302, the optimal DQE point is at 0.06mm, meaning that the optimal location of the photosensor array (e.g., photosensor arrays 105, 205 described above) relative to the total thickness is 0.06mm (60 microns) from the 0 micron point or from the back side of the thinner screen that receives the incident X-rays. By having the photosensor array at 0.06mm to maximize DQE, the ratio of the thicknesses of the two screens at this time is about 37%.

Fig. 3 illustrates a graph 304, where the graph 304 represents the roberts factor, DQE, and schwann factor using a dual-screen structure (e.g., structures 100, 200, and/or 300) without a reflective layer. As shown in graph 304, the DQE is lower than the DQE shown in graph 302, meaning that by including a reflective layer will increase the DQE of the imaging system. The Roberts factor describes the drop in DQE, which results from differences in the spatial spread of light caused by X-ray absorption events occurring at different distances from the photosensor array.

Fig. 4 illustrates an example result example of performance metrics related to dual-screen digital radiography utilizing an asymmetric reflective screen, arranged in accordance with at least some embodiments described herein. Fig. 4 may be described below with reference to the above description of fig. 1 to 3.

Graph 402 shows the results of a number of calculations in which a single-sided intensifying screen is subdivided into two sections of different relative thicknesses and clamped around the photosensor array at different locations as shown on the x-axis of graph 402. Similar to the example of fig. 3, the dual screen structure associated with graph 402 includes (e.g., structures 100 and/or 200) a white backing (reflective layers 112, 122) and has a resolution of 5lp/mm (line pairs/millimeter). The total thickness of the two screens is 160 microns. The incident x-ray beam at 70kVp RQA5 is incident from the left side. Graph 402 shows the MTF and Normalized Noise Power Spectrum (NNPS) for each configuration. The optimal MTF point is at 0.04mm, which means that the optimal location of the photosensor array (e.g., photosensor arrays 105, 205 described above) with respect to total thickness is 0.04mm (40 microns) from the 0 micron point or backside of the thinner screen that receives the incident X-rays. By having the photosensor array at 0.06mm to maximize the MTF, the ratio of the thicknesses of the two screens at this time is about 25%.

Fig. 5 illustrates the difference between the standard configuration of an X-ray detector and the dual screen configuration described in this disclosure. As shown in fig. 5, the standard construction includes one scintillator and the glass substrate is the lowest layer of the detector. The dual screen configuration adds another screen ("screen 2") that is thicker than the top screen ("screen 1") underneath the glass substrate, and both the top and bottom screens have their own reflective backings.

Fig. 6 shows experimental results demonstrating MTF differences between a standard or conventional configuration with one screen and the dual screen configuration described in the present disclosure. As shown in fig. 6, the modeled MTF for the dual-screen configuration is greater than that of the conventional configuration in both the high-sensitivity and high-resolution configurations. As also shown in fig. 6, the measured MTF for the dual-screen configuration is greater than the measured MTF for the conventional configuration in both the high-sensitivity and high-resolution configurations.

Fig. 7 shows experimental results showing DQE differences for the standard configuration with one screen and the dual screen configuration described in this disclosure. The experimental results shown in fig. 7 are based on experiments using RQA9 incident X-ray beams. As shown in fig. 7, the measured DQE for the two-screen configuration is greater than the DQE for the conventional configuration.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of all means or step plus function elements, if any, in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as a specific claim. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.