Medical imaging detector with different surface finishes

Abstract

A medical imaging detector includes a first group of first detector elements and a second group of second detector elements. Each of the first detector elements defines at least one first surface with a first surface finish. Each of the second detector elements defines at least one second surface with a second surface finish that is substantially different from the first surface finish to optimize scintillation light distributions.

Description

TECHNICAL FIELD

[0001] The present disclosure generally relates to medical imaging systems, and more particularly to a medical imaging detector with different surface finishes.BACKGROUND

[0002] Imaging gamma detectors for positron emission tomography (PET) systems typically employ scintillator material to absorb the energy of incident gamma rays from various sources. Light sensors (or photodetectors) in the detectors are used to measure the resulting scintillation light distribution. The location of a gamma interaction event and the energy deposited on the scintillator material is determined from the light sensor (or photodetector) signals.

[0003] A common arrangement for PET uses individual scintillator detector elements in an array surrounded by optical reflector material, and another array of photodetectors (or light sensors), optically coupled to the face of the detector elements opposite the radiation entrance face. The sum of the sensor signals reflects the total energy deposited, and the distribution of scintillation light between the photodetectors provides positioning information.

[0004] Event position is usually computed by calculating the first moments of the photodetector signals, normalized by the total energy. These x and y values can be associated with detector element indices i and j by noting that, due to the partial "light piping" behavior of the light in the detector array, events within each detector element tend to result in calculated positions within identifiable "peaks" that are observed in two-dimensional histograms called position profile maps or flood maps, of many gamma events. Proper identification of the detector element associated with an event requires these peaks to be sufficiently separated in the position profile map image.

[0005] Compression of the peak positions at the outer edges of the detector array, due to reflection of light at the outer boundaries and insufficiently distinct sampling of the light distribution at the sensor array, may occur for some otherwise useful configurations of detector elements and light sensors. This occurs most often when a detector design consists of many smaller detector elements and a relatively small number of light sensors. If some peaks exhibit significant overlap or even merging into a single peak, then correct identification of the detector element of interaction becomes less accurate or even impossible. Furthermore, differences in light scattering of adjacent detector elements, due to bulk scattering or surface finish inconsistencies, can also decrease the separation of their respective peaks in the position profile, so detector designs that have poor separation between edge and adjacent inner detector elements can be more sensitive to such inconsistencies, and thus are prone to failure due to merging of these position profile peaks.SUMMARY

[0006] Described herein is a medical imaging detector. The medical imaging detector includes a first group of first detector elements and a second group of second detector elements. Each of the first detector elements defines at least one first surface with a first surface finish. Each of the second detector elements defines at least one second surface with a second surface finish that is substantially different from the first surface finish to optimize scintillation light distributions.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A more complete appreciation of the present disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

[0008] FIG. 1 is a perspective illustration of an exemplary medical imaging detector;

[0009] FIG. 2 is a cross-sectional side elevation view of the exemplary medical imaging detector;

[0010] FIG. 3 shows a top view of an exemplary detector array of the medical imaging detector;

[0011] FIG. 4 shows an exemplary typical position profile map;

[0012] FIG. 5 shows another exemplary typical position profile map; and

[0013] FIG. 6 shows exemplary position profile maps.DETAILED DESCRIPTION

[0014] In the following description, numerous specific details are set forth such as examples of specific components, devices, methods, etc., in order to provide a thorough understanding of implementations of the present framework. It will be apparent, however, to one skilled in the art that these specific details need not be employed to practice implementations of the present framework. In other instances, well-known materials or methods have not been described in detail in order to avoid unnecessarily obscuring implementations of the present framework. While the present framework is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. Furthermore, for ease of understanding, certain method steps are delineated as separate steps; however, these separately delineated steps should not be construed as necessarily order dependent in their performance.

[0015] Unless stated otherwise as apparent from the following discussion, it will be appreciated that terms such as "segmenting,” “generating,” "registering," "determining," "aligning,” “positioning,” “processing," "computing,” “selecting," "estimating," "detecting," "tracking" or the like may refer to the actions and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (e.g., electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices. Embodiments of the methods described herein may be implemented using computer software. If written in a programming language conforming to a recognized standard, sequences of instructions designed to implement the methods can be compiled for execution on a variety of hardware platforms and for interface to a variety of operating systems. In addition, implementations of the present framework are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used.

[0016] There are several methods to control scintillation light distributions, and thus the sampling of these distributions by the array of photodetectors. One method is to increase the granularity of light sampling by increasing the number (and decreasing the size) of the photodetectors, which requires increasing the number of channels of readout circuitry. Other methods that do not add additional readout circuitry include interposing reflectors or partial reflectors between certain detector elements, the use of a light guide with various optical structures or properties placed between the detector array and the photodetector array, and manipulation of detector element internal reflection properties by surface finish treatments. Edge compression observed for some combinations of desired sensor array size and characteristics and specific detector element size cannot be effectively mitigated by these methods alone. Some detector designs use control of the detector element surface finish by polishing primarily to improve the detector coincidence resolving time, although some polishing will also affect the overall position profile quality. However, these designs use the same surface finish preparation for all detector elements.

[0017] In accordance with one aspect of the present framework, a detector array is fabricated such that the detector elements define different surface finishes to optimize scintillation light distributions. The surface finishes may be pre-selected according to the locations of the detector elements in the array. For example, the surface finish on detector elements at the outside edges of the array is substantially different from that used on interior detector elements. Advantageously, the present framework mitigates the problem of edge compression present in prior detector designs, achieves good separation of peaks in the position profile map and thus enables accurate detector element identification. The present framework enables the use of a specific photodetector array with a desired detector element size that normally exhibits relatively poor edge separation performance.

[0018] Although embodiments of the present disclosure may be described in the context of positron emission tomography (PET) imaging system, it should be understood that other imaging systems, such as such as X-ray imaging, fluoroscopy, single photon emission computed tomography (SPECT), computed tomography (CT), gamma camera and digital mammography systems, are contemplated as being used.

[0019] FIG. 1 is a perspective illustration of an exemplary medical imaging detector 100. Medical imaging detector 100 may be used for imaging applications such as X-ray imaging, fluoroscopy, positron emission tomography (PET), single photon emission computed tomography (SPECT), computed tomography (CT), gamma camera and digital mammography systems. For example, medical imaging detector 100 is a pixelated gamma detector used for PET. In some implementations, medical imaging detector 100 includes an M x N array of detector elements 102 for use in association with a medical imaging device (not shown). For illustration purposes, the medical imaging detector 100 is shown as defining an 8×8 square matrix of detector elements 102. However, it should be appreciated that “M” and “N” are independently selectable, with "M" being less than, equal to, or greater than “N”. It should also be understood that the medical imaging detector 100 can be of other geometric configurations, such as diamond, triangular, rectangular, hexagonal, octagonal, or a combination thereof.

[0020] Detector elements 102 are made of scintillator materials that are capable of detecting radioactivity. Exemplary scintillator materials include, but are not limited, Lutetium oxyorthosilicate (LSO) or lutetium yttrium oxyorthosilicate (LYSO) scintillation crystals. A mechanism 104 for maintaining the relative positions of the individual detector elements 102 with respect to each other may be provided. In some implementations, the mechanism 104 is a retainer disposed about the outermost detector elements 102 to maintain the relative positions of the individual detector elements 102. The retainer 104 may be fabricated from materials such as an adhesive layer, shrink wrap, rubberized bands, tape or a combination of like materials that may be used to enclose or hold the array together in a tight, uniform fashion. Other types of retainers are also possible. For instance, the optical coupling between the detector elements 102 and the light sensor or light guide at the optical exit facing may be an adhesive that holds them in position.

[0021] In some implementations, the array of detector elements 102 is encircled by an outer reflector 105. An upper reflector 107 may also be disposed on top (i.e., radiation entrance face) of the detector elements 102. The outer reflector 105 and upper reflector 107 serve to contain and preserve the scintillation light, but may logically contribute to the edge compression effect. The outer reflector 105 and upper reflector 107 are fabricated from reflective materials, such as films (e.g., optical enhancement films), powders, paints (e.g., reflective paint), plastics (e.g., layers of expanded polytetrafluoroethylene), or metals. In some implementations, the outer reflector 105 also serves as the retainer mechanism 104. For example, the outer reflector 105 may be a reflective film that has an adhesive layer that holds the detector elements 102 in position. The materials of manufacture are selected depending on the wavelength of light emitted by the detector elements 102 and the characteristics of transmissivity and reflectance that is needed.

[0022] FIG. 2 is a cross-sectional side elevation view of the exemplary medical imaging detector 100 along line A-B of FIG. 1. An array of detector elements 102a-102b are coupled to at least one photodetector 204 selected from, but not limited to, silicon photomultiplier (SiPM), photomultiplier tubes (PMT), position sensitive photomultiplier tubes, avalanche photodiodes (APD), pin diodes, CCDs, and other solid state detectors. In some implementations, an array of photodetectors 204 is provided. The array of photodetectors 204 may define, for example, a 4x4 square matrix of photodetectors.

[0023] It should be appreciated that other configurations of the photodetectors 204 are also possible. For example, multiple arrays of photodetectors may be provided. In a double-ended readout arrangement, two arrays of photodetectors are provided. For instance, one array of photodetectors may be positioned on the radiation entrance face of the detector element array, while another array of photodetectors may be positioned on the radiation exit face of the detector element array. Other configurations that provide additional photodetectors on the sides of the detector element array may also be provided. These arrangements can determine the depth of interaction (DOI) of the events within the detector elements 102a-102b.

[0024] In some implementations, a light guide 202 is selectively placed between the detector elements 102-102b and the receiving photodetectors 204. The light guide 202 defines a selected configuration, such as being segmented or continuous. It will be understood that the light guide 202 is optional and, when employed, is optimized depending on the choice of detector elements 102a-102b and photodetectors 204.

[0025] Detector elements 102a-102b disposed within the detector element array serve to detect incident photons and thereafter produce light signals corresponding to the amount of energy deposited from the initial interaction between the photons and the detector elements 102a-102b. A first group of detector elements 102a and a second group of detector elements 102b may be arranged in a detector array. More than two groups of detector elements are also possible. For example, a third group of detector elements (not shown) may be located in the interior of the detector array. Each detector element 102a-102b defines lateral surfaces 210a, a top surface 210b and a bottom surface 210c. Light is reflected and channeled down the detector elements 102a-102b to the coupled light guide 202 and to the photodetector 204. The signals generated by the photodetectors 204 are then post-processed and utilized in accordance with the purpose of the imaging device.

[0026] Air gaps (not shown) may be formed between the detector elements 102a-102b to serve as reflectors. The air gaps serve to control the transmission used for early light sharing and reflection of the scintillation light within the detector elements 102a-b. The air gaps, in conjunction with the different surface finishes, may be used instead of physical reflectors, as they enable potentially less costly fabrication of the detector 100 and greater control of the light distribution. Additionally, physical reflectors may decrease the volume of scintillator material within a fixed detector size, thus reducing gamma sensitivity.

[0027] In some implementations, the first group of detector elements 102a define at least one first surface 210a-c with a first surface finish, while the second group of detector elements 102b define at least one second surface 210a-c with a second surface finish. The second surface finish is substantially different (e.g., more diffuse) from the first surface finish to optimize scintillation light distributions. The first surface and the second surface may be lateral surfaces 210a, top surfaces 210b, bottom surfaces 210c, or a combination thereof. Additionally, or in combination thereof, the lateral surfaces 210a may be processed to achieve a pre-selected finish substantially different from the surface finish of the top and / or bottom surfaces 210b-210c of each detector element (102a or 102b). Other configurations are also possible.

[0028] The first and second surface finishes may be pre-selected according to respective locations or orientations of the first and second detector elements 102a-b in the detector array. For example, detector elements 102a located along one or more edges of the array have a substantially smoother surface finish than the detector elements 102b located in the interior of the detector array. More than two groups of detector elements with more than two substantially different surface finishes may also be provided. For example, a first group of detector elements located at the corners of the detector array may have substantially smoother surface finish than a second group of detector elements located along edges of the detector array. The second group of detector elements may have a substantially smoother surface finish than, for example, a third group of detector elements.

[0029] To process the detector elements 102a-102b, various processing methods may be applied, including, but not limited to, mechanical polishing, chemical polishing, fire polishing or coating with a substance that has an intermediate index of refraction. For example, for a diffuse surface cut by an abrasive saw, the surface may be coated with an optical adhesive, epoxy, acrylic or other suitable substance, resulting in a clear surface. Finish parameters may be varied to achieve the substantially different surface finishes. Examples of finish parameters include, but are not limited to, a mechanical polishing time, a chemical etching time, a chemical composition, a chemical concentration, an etching temperature, a thickness of coating, a composition of coating, or a combination thereof. Any other parameter that impacts light distribution between internal reflection in the detector element and scattering out of the detector element may also be used.

[0030] The substantially different surface finishes enable the tuning and optimization of the resulting scintillation light distributions, thereby ensuring the separability of resulting pixels in the position profile map. Additionally, uniformity in the detector performance parameters may be improved and the average value of the energy resolution or coincidence resolving time of the detector elements 102a-102b may be lowered.

[0031] FIG. 3 shows a top view of an exemplary detector array 302 of the medical imaging detector 100. The first group of detector elements 102a are outermost detector elements disposed along the edges of the detector array 302, while the second group of detector elements 102b are the remaining inner detector elements. Outermost detector elements 102a are processed with a smoother surface finish than the inner detector elements 102b to mitigate corner or edge compression problems. More particularly, the lateral surfaces of the outermost detector elements 102a may be provided with a smoother surface finish than the lateral surfaces of the inner detector elements 102b. Additionally, or alternatively, the top and / or bottom surfaces of the outermost detector elements 102a may have a smoother finish than the top and / or bottom surfaces of the inner detector elements 102b. The smoother surface finish with less scattering promotes internal reflection of a higher fraction of light propagation down the detector elements 102a. Thus, the first moment or centroid of the light distribution is shifted outward, relative to that which will be characteristic of the light distribution in the case of all detector elements 102a-102b having the same surface finish.

[0032] It should be appreciated that other configurations are also possible. The surface finish may vary according to the location and / or orientation of the detector elements 102a-102b in the detector array 302. For example, the first group of detector elements 102a may be positioned only at the corners of the detector array, while the second group of detector elements 102b may be positioned along the edges and within the interior of the detector array. The array may also include more than two groups of detector elements with more than two pre-selected surface finishes. These methods of controlling light distributions through the detector 100 may also be combined with other methods (e.g., air gaps or reflectors between detector elements).

[0033] FIG. 4 shows an exemplary typical position profile map 402. The position profile map 402 is acquired by irradiating a typical detector with a radioactive point source. The typical detector is a 16 mm square miniblock, comprising a 4x4 array of SiPM photodetectors and a 5x5 array of 3.2 mm LSO detector elements.

[0034] The position profile map 402 may be segmented to discriminate event locations within the detector elements. Other methods, such as machine learning, may also be used. The position profile map 402 exhibits excellent peak separation due to the relatively small number and positions of the detector elements relative to the number and positions of SiPM photodetectors. The outermost and adjacent detector elements' exit faces couple their direct scintillation light primarily to different SiPM photodetectors, resulting in significant differences in the SiPM index-weighted position calculations. Light that penetrates or scatters out of the detector elements contributes to overall position profile compression, but the combined direct and distributed light centroids are sufficiently different for all the detector elements to produce the clear separation seen here.

[0035] FIG. 5 shows another exemplary typical position profile map 502. The position profile map 502 is acquired by irradiating a typical detector with a radioactive point source. The typical detector is a higher resolution 16 mm square miniblock, comprising a 4x4 array of SiPM photodetectors and an 8x8 array of 2 mm LSO detector elements. Since the typical detector is not optimized with different pre-selected surface finishes, the position profile map 502 exhibits significant edge compression 504. The outermost and adjacent detector elements' exit faces couple their direct scintillation light to the same edge SiPM photodetector, and those contributions to the centroid calculations cause the peaks to be much closer. Accordingly, the design is sensitive to slight block mispositioning (e.g., a shift left causing failure due to edge compression as seen on the left side 504) and to variations in surface finish and bulk scattering which can result in adjacent peaks merging (e.g., as seen in the fourth row on the right side 506).

[0036] FIG. 6 shows exemplary position profile maps 602a-c. The position profile maps 602a-c are acquired by irradiating a medical imaging detector 100 as described herein with a radioactive point source. The medical imaging detector 100 is a higher resolution 16 mm square miniblock, comprising a 4x4 array of SiPM photodetectors and an 8x8 array of 2 mm LSO detector elements. The outermost detector elements 102a are processed to achieve a smoother surface finish relative to inner detector elements 102b surface finishes, resulting in reduced edge compression. Position profile map 602a is the result of slightly smoother outer detector elements, while position profile maps 602b-c show the effect of increasing smoothness. The separation of the outer pixels is sufficient to ensure complete segmentation of the position profile map, even in cases of undesired variations in surface characteristics of certain individual detector elements 102a-b, when the difference in smoothness is significant enough.

[0037] The proposed framework achieves the desired improvement of the position profile map quality for edge detector elements, enabling unambiguous pixel identification, while avoiding many of the disadvantages of other commonly used methods. It is desirable to minimize the number of photodetectors used, and thus reduce the amount of readout circuitry required, and to use existing detector array arrangements (e.g., number of detector elements) and readout circuitry, such as application specific integrated circuits (ASICs) available from other detector designs and a 4x4 photodetector readout.

[0038] As described above, the present framework enables a 4x4 photodetector array to be successfully applied to a detector array with more detector elements and smaller pixels than the detector array was originally intended for. The present framework does not require introduction of inter-detector element reflectors, which reduce the areal gamma sensitivity of a detector and increase the complexity and difficulty of fabrication, and thus, cost of the detector. Light guides, particularly structured or segmented ones that control the spread of light from different detector elements in varied ways, can be costly, and the presence of a light guide introduces optical interfaces and will typically increase optical path length jitter, thus degrading the detector coincidence resolving time.

[0039] The following is a list of non-limiting illustrative embodiments disclosed herein:

[0040] Illustrative embodiment 1. A medical imaging detector comprising: a first group of first detector elements, wherein each of the first detector elements defines at least one first surface with a first surface finish; and a second group of second detector elements, wherein each of the second detector elements define at least one second surface with a second surface finish that is substantially different from the first surface finish to optimize scintillation light distributions.

[0041] Illustrative embodiment 2. The medical imaging detector of illustrative embodiment 1 further comprising at least one photodetector, wherein the first group of the first detector elements and the second group of the second detector elements are coupled to the at least one photodetector.

[0042] Illustrative embodiment 3. The medical imaging detector of illustrative embodiment 2 wherein the first group of the first detector elements and the second group of the second detector elements define an 8x8 square matrix of detector elements and the at least one photodetector comprises an array of photodetectors that define a 4x4 square matrix of photodetectors.

[0043] Illustrative embodiment 4. The medical imaging detector of illustrative embodiment 2 further comprising a light guide selectively disposed between the first and second detector elements and the at least one photodetector.

[0044] Illustrative embodiment 5. The medical imaging detector of any one of illustrative embodiments 1-4 wherein air gaps are formed between the first and second detector elements to serve as reflectors.

[0045] Illustrative embodiment 6. The medical imaging detector of any one of illustrative embodiments 1-5 wherein the first and second surface finishes are pre-selected according to respective locations of the first and second detector elements.

[0046] Illustrative embodiment 7. The medical imaging detector of any one of illustrative embodiments 1-6 wherein the first surface finish is substantially smoother than the second surface finish.

[0047] Illustrative embodiment 8. The medical imaging detector of illustrative embodiment 7 wherein the first group of the first detector elements are outermost detector elements located along one or more edges of a detector array.

[0048] Illustrative embodiment 9. The medical imaging detector of illustrative embodiment 7 wherein the first group of the first detector elements are located at corners of a detector array.

[0049] Illustrative embodiment 10. The medical imaging detector of any one of illustrative embodiments 1-9 further comprising one or more additional groups of additional detector elements with respective one or more surface finishes that are substantially different from the first and second surface finishes.

[0050] Illustrative embodiment 11. The medical imaging detector of illustrative embodiment 10 wherein the first group of the first detector elements are located at corners of a detector array, the second group of the second detector elements are located along edges of the detector array and the one or more additional groups of additional detector elements are located in an interior of the detector array.

[0051] Illustrative embodiment 12. The medical imaging detector of any one of illustrative embodiments 1-11 wherein the at least one first surface and the at least one second surface comprise lateral surfaces, top surfaces, bottom surfaces, or a combination thereof.

[0052] Illustrative embodiment 13. A medical imaging detector, comprising: detector elements disposed in a detector array, wherein the detector elements define at least two substantially different surface finishes that are pre-selected based on respective locations of the detector elements in the detector array to optimize scintillation light distributions.

[0053] Illustrative embodiment 14. The medical imaging detector of illustrative embodiment 13 wherein a first surface finish pre-selected for detector elements located along edges of the detector array is substantially smoother than a second surface finish pre-selected for detector elements located in an interior of the detector array.

[0054] Illustrative embodiment 15. The medical imaging detector of illustrative embodiment 13 wherein a first surface finish pre-selected for detector elements located at corners of the detector array is substantially smoother than a second surface finish pre-selected for detector elements located in an interior of the detector array.

[0055] Illustrative embodiment 16. The medical imaging detector of illustrative embodiment 13 wherein a first surface finish pre-selected for detector elements located at corners of the detector array is substantially smoother than a second surface finish pre-selected for detector elements located along edges of the detector array.

[0056] Illustrative embodiment 17. The medical imaging detector of illustrative embodiment 16 wherein the second surface finish is substantially smoother than a third surface finish pre-selected for detector elements located in an interior of the detector array.

[0057] Illustrative embodiment 18. A method of fabricating a medical imaging detector, comprising: processing a first group of first detector elements to define at least one first surface with a first surface finish; and processing a second group of second detector elements to define at least one second surface with a second surface finish that is substantially different from the first surface finish.

[0058] Illustrative embodiment 19. The method of illustrative embodiment 18 wherein processing the first group of the first detector elements comprises performing processing with a first finish parameter, and processing the second group of the second detector elements comprises performing processing with a second finish parameter that is substantially different from the first finish parameter.

[0059] Illustrative embodiment 20. The method of illustrative embodiment 19 wherein the first and second finish parameters comprise a mechanical polishing time, a chemical etching time, a chemical composition, a chemical concentration, an etching temperature, a thickness of coating, a composition of coating, or a combination thereof.

[0060] While the present framework has been described in detail with reference to exemplary embodiments, those skilled in the art will appreciate that various modifications and substitutions can be made thereto without departing from the spirit and scope of the invention as set forth in the appended claims. For example, elements and / or features of different exemplary embodiments may be combined with each other and / or substituted for each other within the scope of this disclosure and appended claims.

Claims

WHAT IS CLAIMED IS:1.A medical imaging detector comprising:a first group of first detector elements, wherein each of the first detector elements defines at least one first surface with a first surface finish; anda second group of second detector elements, wherein each of the second detector elements defines at least one second surface with a second surface finish that is substantially different from the first surface finish to optimize scintillation light distributions.

2. The medical imaging detector of claim 1 further comprising at least one photodetector, wherein the first group of the first detector elements and the second group of the second detector elements are coupled to the at least one photodetector.

3. The medical imaging detector of claim 2 wherein the first group of the first detector elements and the second group of the second detector elements define an 8x8 square matrix of detector elements and the at least one photodetector comprises an array of photodetectors that define a 4x4 square matrix of photodetectors.4.The medical imaging detector of claim 2 further comprising a light guide selectively disposed between the first and second detector elements and the at least one photodetector.5.The medical imaging detector of claim 1 wherein air gaps are formed between the first and second detector elements to serve as reflectors.

6. The medical imaging detector of claim 1 wherein the first and second surface finishes are pre-selected according to respective locations of the first and second detector elements.7.The medical imaging detector of claim 1 wherein the first surface finish is substantially smoother than the second surface finish.

8. The medical imaging detector of claim 7 wherein the first group of the first detector elements are outermost detector elements located along one or more edges of a detector array.

9. The medical imaging detector of claim 7 wherein the first group of the first detector elements are located at corners of a detector array.10.The medical imaging detector of claim 1 further comprising one or more additional groups of additional detector elements with respective one or more surface finishes that are substantially different from the first and second surface finishes.11.The medical imaging detector of claim 10 wherein the first group of the first detector elements are located at corners of a detector array, the second group of the second detector elements are located along edges of the detector array and the one or more additional groups of additional detector elements are located in an interior of the detector array.

12. The medical imaging detector of claim 1 wherein the at least one first surface and the at least one second surface comprise lateral surfaces, top surfaces, bottom surfaces, or a combination thereof.

13. A medical imaging detector, comprising:detector elements disposed in a detector array, wherein the detector elements define at least two substantially different surface finishes that are pre-selected based on respective locations of the detector elements in the detector array to optimize scintillation light distributions.

14. The medical imaging detector of claim 13 wherein a first surface finish pre-selected for detector elements located along edges of the detector array is substantially smoother than a second surface finish pre-selected for detector elements located in an interior of the detector array.

15. The medical imaging detector of claim 13 wherein a first surface finish pre-selected for detector elements located at corners of the detector array is substantially smoother than a second surface finish pre-selected for detector elements located in an interior of the detector array.

16. The medical imaging detector of claim 13 wherein a first surface finish pre-selected for detector elements located at corners of the detector array is substantially smoother than a second surface finish pre-selected for detector elements located along edges of the detector array.

17. The medical imaging detector of claim 16 wherein the second surface finish is substantially smoother than a third surface finish pre-selected for detector elements located in an interior of the detector array.18.A method of fabricating a medical imaging detector, comprising:processing a first group of first detector elements to define at least one first surface with a first surface finish; andprocessing a second group of second detector elements to define at least one second surface with a second surface finish that is substantially different from the first surface finish.19.The method of claim 18 wherein processing the first group of the first detector elements comprises performing processing with a first finish parameter, and processing the second group of the second detector elements comprises performing processing with a second finish parameter that is substantially different from the first finish parameter.20.The method of claim 19 wherein the first and second finish parameters comprise a mechanical polishing time, a chemical etching time, a chemical composition, a chemical concentration, an etching temperature, a thickness of coating, a composition of coating, or a combination thereof.

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