Multifunctional radiation detector

Abstract

A multi-functional and multi-modality radiation detector (10) is provided. The radiation detector (10) comprises at least two detector units (12a, 12b) having photosensitive pixels (14) and at least one scintillation device (20) optically coupled to the photosensitive pixels (14). The detector units (12a, 12b) are arranged next to each other on a substrate foil (24). Therein, the scintillation devices (20) of the detector units (12a, 12b) are spaced apart from each other, such that the radiation detector (10) is bendable. This allows the radiation detector (10) to be used in many different geometrical configurations.

Claims

1. A radiation detector, comprising: a plurality of detectors, each detector comprising a plurality of photosensitive pixels and at least one scintillation device optically coupled to the plurality of photosensitive pixels; a substrate foil for carrying the detectors; and a switch arranged between two detectors of the plurality of detectors, wherein the detectors are arranged in juxtaposition on the substrate foil; wherein at least two directly adjoining scintillation devices of at least two directly adjoining detectors are spaced apart from each other, such that the radiation detector is bendable along at least a part of a bending region of the substrate foil, wherein the bending region is arranged between the at least two directly adjoining scintillation devices; wherein each detector comprises at least one of a separate addressing circuit for addressing the respective detector and a separate signal read-out circuit for reading-out signals from the respective detector; and wherein the switch is configured to electrically interconnect and decouple the two detectors.

2. The radiation detector according to claim 1, wherein the radiation detector is bendable with a bending angle enclosed by the at least two directly adjoining detectors; wherein the bending angle ranges from 0° to 360°.

3. The radiation detector according to claim 1, wherein the substrate foil comprises polymer material.

4. The radiation detector according to claim 1, wherein the plurality of photosensitive pixels comprises an array of photosensitive pixels; wherein each of the photosensitive pixels comprises at least one Thin-Film-Transistor element.

5. The radiation detector according to claim 1, wherein at least one of the plurality of detectors has a curved shape.

6. The radiation detector according to claim 1, wherein each separate addressing circuit and/or each separate signal read-out circuit is arranged on a separate electronics carrying region of the substrate foil.

7. The radiation detector according to claim 1, wherein a first detector of the plurality of detectors is configured for detecting radiation in a first energy range; and wherein a second detector of the plurality of detectors is configured for detecting radiation in a second energy range, the second energy range being at least partly different from the first energy range.

8. The radiation detector according to claim 1, wherein one detector of the plurality of detectors is an X-ray detector configured for detecting X-rays and arranged in a center region of the substrate foil; and wherein at least two detectors of the plurality of detectors are γ-ray detectors arranged on two opposite sides of the X-ray detector.

9. The radiation detector according to claim 1, wherein the at least one scintillation device of each detector of the plurality of detectors comprises a scintillation layer arranged on top of at least a part of the plurality of photosensitive pixels; and/or wherein an edge of the scintillation device is tapered.

10. The radiation detector according to claim 1, wherein each detector is flat.

11. The radiation detector according to claim 1, wherein each detector is bent only at the bending region.

12. The radiation detector according to claim 1, wherein both the addressing circuit and the read-out circuit are provided on one side of the substrate foil.

13. The radiation detector according to claim 12, wherein both the addressing circuit and the read-out circuit are provided as an electronic TFT backplane circuit.

14. The radiation detector according to claim 1, further comprising at least one light shield arranged on the substrate foil.

15. The radiation detector according to claim 1, wherein the substrate foil is arranged in a Z-like shape in at least one of the bending regions.

16. The radiation detector according to claim 1, wherein each neighboring detector of the plurality of detectors is brought closely together by folding the substrate foil at each bending region.

17. A method for producing a radiation detector, the method comprising: providing a substrate foil and a plurality of detectors, each detector comprising a plurality of photosensitive pixels and at least one scintillation device optically coupled to the plurality of photosensitive pixels; arranging the plurality of detectors on the substrate foil in juxtaposition with respect to each other, such that at least two directly adjoining scintillation devices of at least two directly adjoining detectors are spaced apart from each other by a gap, and such that the radiation detector is bendable along at least a part of the gap; and arranging a switch between two detectors of the plurality of detectors, wherein each detector comprises at least one of a separate addressing circuit for addressing the respective detector and a separate signal read-out circuit for reading-out signals from the respective detector; and the switch is configured to electrically interconnect and decouple the two detectors.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The subject matter of the invention will be explained in more detail in the following with reference to exemplary embodiments which are illustrated in the attached figures, wherein:

(2) FIG. 1A shows schematically a top view of a radiation detector;

(3) FIG. 1B shows schematically a cross-sectional view of the radiation detector of FIG. 1A;

(4) FIG. 2A shows schematically a radiation detector in a closed configuration;

(5) FIG. 2B shows schematically the radiation detector of FIG. 2A in a completely unfolded configuration;

(6) FIG. 2C shows schematically the radiation detector of FIG. 2A in a partly unfolded configuration;

(7) FIGS. 3 to 7 each show schematically a top view of a radiation detector in a specific design;

(8) FIG. 8A shows schematically a top view of a radiation detector in a completely unfolded configuration;

(9) FIG. 8B shows schematically the radiation detector of FIG. 8A in a partly unfolded configuration;

(10) FIG. 9A shows schematically a top view of a radiation detector;

(11) FIG. 9B shows schematically a detailed view of a part of the radiation detector of FIG. 9A;

(12) FIGS. 10 to 18 each show schematically a cross-sectional view of a radiation detector in a different geometrical set-up;

(13) FIG. 19A shows schematically a cross-sectional view of a radiation detector;

(14) FIG. 19B shows schematically a side view of the radiation detector of FIG. 19A;

(15) FIG. 20A shows schematically a cross-sectional view of a radiation detector;

(16) FIGS. 20B and 20C each show schematically a detailed view of a part of the radiation detector of FIG. 20A according to different embodiments;

(17) FIG. 21 shows schematically a top view of a radiation detector arrangement;

(18) FIG. 22 shows schematically a flow chart illustrating steps of a method for producing a radiation detector;

(19) FIG. 23 schematically illustrates a method for producing a radiation detector.

(20) In principle, identical parts are provided with the same reference symbols in the figures.

DETAILED DESCRIPTION OF EMBODIMENTS

(21) FIG. 1A shows schematically a top view of a radiation detector 10, and FIG. 1B shows schematically a cross-sectional view of the radiation detector 10 of FIG. 1A. The radiation detector 10 comprises two detector units 12a, 12b.

(22) Each of the detector units 12a, 12b comprise two photosensitive pixels 14, which are exemplary arranged in a row. However, the photosensitive pixels 14 may alternatively be arranged in an arbitrary arrangement with respect to each other. Each of the pixels 14 comprises at least one Thin-Film-Transistor (TFT) element 16.

(23) Further, each of the detector units 12a, 12b comprises a photodiode 18, which at least partly covers a surface of the TFT elements 16 of each detector unit 12a, 12b. In the exemplary embodiment shown in FIGS. 1A and 1B, the pixels 14 are connected to the respective photodiode 18, wherein the photodiodes 18 basically provide photosensitivity to the pixels 14, as explained in more detail below. Alternatively, each of the detector units 12a, 12b may also comprise a plurality of photodiodes 18.

(24) Moreover, each of the detector units 12a, 12b comprises a scintillation device 20 with a scintillation layer 22 arranged on and/or on top of the photosensitive pixels 14. The scintillation layer 22 of each detector unit 12a, 12b may be arranged on top of and/or on a surface of the respective photodiode 18. The scintillation layer 22 may for instance comprise CsI, GOS, garnet and/or NaI as scintillation material.

(25) The detector units 12a, 12b with all the above-described components and/or elements are arranged in juxtaposition with respect to each other and/or next to each other on a flexible substrate foil 24. The detector units 12a, 12b may be at least partly arranged on a surface 25 and/or a top surface 25 and/or an outer surface 25 of the substrate foil 24. The substrate foil 24 may denote a single, large, common substrate foil 24 carrying all or most of the components of each detector unit 12a, 12b. In other words, the substrate foil 24 may be a common substrate foil 24 forming a common carrier element for the detector units 12a, 12b. The substrate foil 24 may e.g. be a monolithic substrate foil 24. Further, the substrate foil 24 may comprise polymer material, such as e.g. Polylmide (PI), PolyTetraFluoroEthylene (PTFE), PolyEthylene Therephtalate (PET), PolyEthylene Naphtalate (PEN), and/or any combination thereof. The substrate foil 24 is flexible, such that it may be bended and/or folded e.g. way more than 10.sup.5 times without noticeable deterioration and/or degradation. The substrate foil 24 may have a thickness ranging from several μm to several thousand μm, for example from 10 μm to 1000 μm, and preferably from 10 μm to 100 μm. Particularly, the substrate foil 24 may have a thickness of about 25 μm.

(26) In order to make use of the flexibility of the substrate foil 24 and/or in order to provide foldability and/or bendability to the radiation detector 10, the two detector units 12a, 12b, which are neighboring each other and/or which are adjacently arranged on the substrate foil 24 are spaced apart from each other by a distance 26, indicated by the arrow in FIGS. 1A and 1B. More precisely, the two directly adjoining scintillation devices 20 of the respective detector units 12a, 12b are spaced apart by the distance 26, wherein the distance 26 may be measured parallel to the surface 25 of the substrate 24 from edges 21 and/or borders 21 of the scintillation device 20 and/or the scintillation layer 22, which edges/borders 21 are opposing each other and/or facing each other. In other words, the edges/borders 21 are arranged opposite to each other. The distance 26 may at least be 0.1 cm, preferably at least 1 cm. However, depending on a thickness of the scintillation devices 20, the distance 26 may range from 1 cm to about 30 cm, for example 3 cm to 20 cm, and preferably 5 cm to 15 cm. By spacing apart the directly adjoining edges/borders 21 of the scintillation device 20 by the distance 26, an interspace 28 and/or a gap 28 is formed between the scintillation devices 20. An area and/or region of the substrate foil 24 arranged within the gap 28 and/or interspace 28 is denoted as bending region 30 of the substrate foil 24. Along at least a part of the bending region 30, the radiation detector 10 is bendable and/or foldable such that the detector units 12a, 12b may basically be displaced and/or relocated with respect to each other in an arbitrary angle around an axis 32 parallel to a longitudinal extension direction of the bending region 30 and/or the gap 28, as further elucidated in following figures.

(27) Moreover, each of the detector units 12a, 12b comprises an electronic addressing circuit 34 for addressing the pixels 14. Amongst others, the addressing circuits 34 of each detector unit 12a, 12b may be configured for driving the pixels 14, e.g. in terms of supplying electric power to these components. The addressing circuits 34 may each comprise e.g. an integrated circuit (IC).

(28) Further, each of the detector units 12a, 12b comprises an electronic signal read-out circuit 36. The signal read-out circuits 36 may each denote a data signal read-out for data and/or signals from the pixels 14 of each of the detector units 12a, 12b, respectively. The signal read-out circuits 36 may each comprise an integrated circuit (IC) and/or an application-specific integrated circuit (ASIC). The signal read-out circuits 36 may further each comprise an analog-digital converter for converting an analog signal to a digital signal.

(29) However, the detector units 12a, 12b, may also share a single addressing circuit 34 and/or a single signal read-out circuit 36. Thus, the detector units 12a, 12b may be electronically interconnected and share common periphery electronics of the radiation detector 10.

(30) Both the addressing circuits 34 and the signal read-circuits 36 may be manufactured as electronic TFT backplane circuits arranged on either side of the substrate foil 24, allowing the radiation detector 10 to be bended and/or folded without performance degradation. The circuits 34, 36 of each detector unit 12a, 12b may be arranged on the same side or on separate sides of the substrate foil 24.

(31) A working principle of the radiation detector 10 may be described as follows. Photons and/or charged particles, such as e.g. electrons, positrons and/or alpha particles, impinging on the scintillation device 20 and/or the scintillation layer 22 excite active species, such as e.g. molecules, in the scintillation layer 22, which in turn de-excite by emission of electromagnetic radiation, such as e.g. visible light. The electromagnetic radiation emitted by the scintillation layer 22 and/or the scintillator device 20 then impinges on the photodiode 18, which converts the electromagnetic radiation to an electric signal, i.e. a current and/or a voltage, which electric signal may in turn be transferred to the signal read-out circuits 36 of the radiation detector 10 via at least one of the TFT elements 16. This provides an electronic signal, which correlates with a primarily impinged radiation particle and/or the energy deposited by it in the scintillation device 20. The electronic signal may then be converted to a digital signal, which may be further processed for final image acquisition.

(32) It should be noted here, that the two detector units 12a, 12b may be configured for detecting radiation with differing energies. By way of example, detector unit 12a may denote a first detector unit 12a configured for detecting radiation in a first energy range, and detector unit 12b may denote a second detector unit 12b configured for detecting radiation in a second energy range, which second energy range at least partly differs from the first energy range. The first and second energy range may at least partly overlap.

(33) For instance, the first detector unit 12a may be an X-ray detector unit 12a configured for detecting X-rays and the second detector unit 12b may be a γ-ray detector unit 12b.

(34) In order to provide sensitivity in different energy ranges, the first detector unit 12a and second detector unit 12b may e.g. differ in size of the pixels 14, in scintillation material, in thickness of the scintillation device 20 and/or the scintillation layer 22 comprised therein and/or in the electronics, i.e. the addressing circuit 34 and/or signal read-out circuit 36, respectively. For detecting higher energies, e.g. a thicker scintillation layer 22 comprised in the scintillation device 20 may be used.

(35) Measuring and/or detecting different energies with each of the detector units 12a, 12b may advantageously provide a multi-functionality and/or multi-modality to the radiation detector 10.

(36) In common or standard detectors, multi-functionality may only be realized by connecting separate smaller detectors closely together, which inevitably leads to high cost price.

(37) According to the inventive radiation detector 10 described with reference to FIGS. 1A and 1B above a multi-functional radiation detector 10 can be manufactured from a single sensor-on-foil substrate 24 produced in one process manufacturing flow. Also commonly available scintillation devices 20 and/or radiation detector 10 assembly processes may be used, thereby reducing production cost for the inventive radiation detector 10.

(38) Further, e.g. in clinical procedures with multiple imaging tasks, such as e.g. X-ray and γ-ray for SIRT, oncology IGT or the like, may require intermediate patient transport and may be time consuming using common or standard detectors.

(39) In contrast, with the inventive multi-modality radiation detector 10 described with reference to FIGS. 1A and 1B, such procedures may be simplified and/or shortened without need for intermediate patient transport.

(40) Moreover, common or standard radiation detectors may have one fixed combination of a sensor and a scintillator which ideally only meets requirements for an “average application”. This may limit user flexibility, application range and may lead to undesired high X-ray dose usage.

(41) In contrast, the inventive radiation detector 10 described with reference to FIGS. 1A and 1B may be equipped with multiple sensors, i.e. detector units 12a, 12b comprising multiple scintillation device 20 combinations, which may each be optimized for a specific imaging application requirement, such as for low or high dose, for low or high kV, for low or high resolution or the like. This may provide a more effective usage of radiation dose, such as X-ray dose.

(42) Moreover, common detectors and systems may only have one imaging function, such as an X-ray function or a γ-ray function.

(43) In contrast, as described above with reference to FIGS. 1A and 1B, the inventive radiation detector 10 provides multi-modality detection of radiation in terms of combining both X-ray and γ-ray imaging in one radiation detector 10.

(44) Apart from that, in common detectors, repeated folding/unfolding and/or curving of a “standard” detector on a common substrate may lead to local damage of the scintillation devices and to degradation of imaging performance.

(45) In contrast, in the inventive radiation detector 10 all detector units 12a, 12b may be flat and may only be folded at the bending region 30 and/or the gap 28 which is not covered with any scintillation device 20 and/or scintillation layer 22. This may provide a high degree in robustness and durability.

(46) The radiation detector according to the exemplary embodiment shown in FIGS. 1A and 1B is briefly summarized in the following. As described, a design of a compact foldable radiation detector 10 is provided which can be unfolded temporary to actuate a larger configuration of multiple flat detector units 12a, 12b connected to each other. The detector units 12a, 12b can be flexibly positioned at any desired angle (i.e. bending angle 50 as shown in subsequent figures) with respect to each other, and have their own specific photosensitive pixels 14 and scintillation device 20. The basic large substrate foil 24 in the radiation detector 10 comprises a single thin plastic foil 24 on which various smaller photosensitive pixels 14 are manufactured. The large substrate foil 24 is preferably produced in one process flow using TFT backplane and photodiode manufacturing processes. A multi-functional radiation detector 10 may be realized by designing its detector units 12a, 12b so that they may be enabled to operate individually and/or acquire images e.g. from different radiation exposures.

(47) FIG. 2A shows schematically a radiation detector 10 in a closed configuration. FIG. 2B shows schematically the radiation detector 10 of FIG. 2A in a completely unfolded configuration, and FIG. 2C shows schematically the radiation detector 10 of FIG. 2A in a partly unfolded configuration.

(48) If not stated otherwise, the radiation detector 10 of FIGS. 2A to 2C comprises the same features, functions and/or elements as the radiation detector 10 of FIGS. 1A and 1B.

(49) The radiation detector 10 of FIGS. 2A to 2C comprises in total five detector units 12a, 12b, 12c, 12d and 12e, which each have a rectangular shape.

(50) A center detector unit 12a may be larger than the other detector units 12b to 12e. By way of example, the center detector unit 12a may be an X-ray detector unit 12a and the other detector units 12b to 12e may be γ-ray detector units. Alternatively, all detector units 12a to 12e may be configured for detecting radiation particles, e.g. photons, in different energy ranges, which energy ranges may also overlap.

(51) As shown in FIG. 2B, the detector units 12b and 12d have the same size and are arranged on two opposite sides 11a and 11b of detector unit 12a, respectively.

(52) Similarly, the detector units 12c and 12e have the same size and are arranged on two opposite sides 11c and 11d of detector unit 12a, respectively.

(53) As evident from FIGS. 2A to 2C, the radiation detector 10 is folded to a rather compact configuration shown in FIG. 2A and can be entirely unfolded to the configuration depicted in FIG. 2B, thereby increasing an effective detector area.

(54) As illustrated in FIG. 2C, since each of the detector units 12b to 12e can be independently folded and/or bended, the radiation detector 10 may be used in a multitude of different geometrical configurations ranging from the completely folded configuration shown in FIG. 2A to the completely unfolded configuration shown in FIG. 2B.

(55) Summarizing, a design of a compact foldable radiation detector 10 is provided which can be unfolded temporary to actuate a larger configuration of multiple flat detector units 12a to 12e connected to each other. The detector units 12a to 12e can be flexibly positioned at any desired angle (i.e. bending angle 50 as shown in subsequent figures) with respect to each other.

(56) Each detector unit 12a to 12e comprises photosensitive pixels 14 at least partly covered with a specific scintillation device 20, and each detector unit 12a to 12e may be optimized for specific X-ray and/or γ-ray imaging requirements. Each detector unit 12a to 12e may have its own specific arrangement of pixels 14 and/or TFT elements 16 and/or periphery electronics 34, 36 for addressing and data signal read-out.

(57) The basic large substrate foil 24 comprises a single thin plastic foil on which various smaller photosensitive pixels 14 are manufactured. The large substrate foil 24 may preferably be produced in one process flow using TFT backplane and photodiode manufacturing processes.

(58) A multi-functional radiation detector 10 is realized by designing its detector units 12a to 12e so that they are enabled to operate individually and acquire images from different radiation exposures. Images of the detector units 12a to 12e can be acquired simultaneously and/or sequentially. They can be processed, merged and/or reconstructed to generate anatomical and/or functional information.

(59) FIG. 3 shows schematically a top view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 3 comprises the same features, functions and/or elements as the radiation detectors 10 shown in previous figures.

(60) The radiation detector of FIG. 3 comprises in total nine detector units 12a to 12i. Therein, the detector units 12a to 12e correspond to the detector units 12a to 12e of FIGS. 2A to 2C.

(61) Additionally, small-size detector units 12f, 12g, 12h, 12i are arranged at each corner of the center detector unit 12a, which provides an even larger overall detection area to the radiation detector 10.

(62) FIG. 4 shows schematically a top view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 4 comprises the same features, functions and/or elements as the radiation detectors 10 shown in previous figures.

(63) The radiation detector 10 of FIG. 4 comprises in total two detector units 12a, 12b, which are arranged next to each other and differ in size. Detector unit 12a may be considered the main detector unit, which is bordered on an edge 11 by detector unit 12b.

(64) FIG. 5 shows schematically a top view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 5 comprises the same features, functions and/or elements as the radiation detectors 10 shown in previous figures.

(65) The radiation detector 10 of FIG. 5 comprises in total five detector units 12a to 12e. Along each side and/or edge 11a to 11d of a respective detector unit 12a to 12e, the detector units 12a to 12e may be folded allowing a multitude of various geometrical configurations. All detector units 12a to 12e have a square shape and have the same size. Thus, a detector area may be increased by a factor of five from a completely folded configuration to a completely unfolded configuration.

(66) FIG. 6 shows schematically a top view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 6 comprises the same features, functions and/or elements as the radiation detectors 10 shown in previous figures.

(67) The radiation detector 10 of FIG. 6 comprises in total three detector units 12a to 12c. Along each side and/or edge 11a to 11b of a respective detector unit 12a to 12c, the detector units 12a to 12c may be folded allowing a multitude of various geometrical configurations. All detector units 12a to 12c have a square shape and have the same size. Thus, a detector area may be increased by a factor of three from a completely folded configuration to a completely unfolded configuration.

(68) FIG. 7 shows schematically a top view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 7 comprises the same features, functions and/or elements as the radiation detectors 10 shown in previous figures.

(69) The radiation detector 10 of FIG. 7 comprises in total six detector units 12a to 12f. Along each side and/or edge 11a to 11e of a respective detector unit 12a to 12f, the detector units 12a to 12f may be folded allowing a multitude of various geometrical configurations. All detector units 12a to 12f have a rectangular shape and have the same size. Thus, a detector area may be increased by a factor of six from a completely folded configuration to a completely unfolded configuration.

(70) FIG. 8A shows schematically a top view of a radiation detector 10 in a completely unfolded configuration, and FIG. 8B shows schematically the radiation detector 10 of FIG. 8A in a partly unfolded configuration. If not stated otherwise, the radiation detector 10 of FIGS. 8A and 8B comprises the same features, functions and/or elements as the radiation detectors 10 shown in previous figures.

(71) The radiation detector 10 comprises in total five detector units 12a to 12e, corresponding to the detector units 12a to 12e of FIGS. 2A and 2B.

(72) Further, the radiation detector 10 comprises in total four separate electronics units 13a to 13d, wherein at each corner of the center detector unit 12a one of those electronics units 13a to 13d is arranged. Each of the electronics units 13a to 13d comprise a separate signal read-out circuit 36. Each of those separate signal read-out circuits 36 is arranged on a separate electronics carrying region 15a to 15d of the substrate foil 24.

(73) In order to provide foldability of each of the detector units 12b to 12e along each of edges 11a to 11d (corresponding to sides 11a to 11d of detector unit 12a), between each of the electronics units 13a to 13d and at least one directly adjoining and/or neighboring detector unit 12b to 12e, the substrate foil 24 comprises a cut 17a to 17d and/or 19a to 19d.

(74) By way of example, for electronics units 13a, 13b cuts 17a, 17b are present in the substrate foil 24, as illustrated in FIG. 8B. Alternatively or additionally cuts 19a, 19b may be present. The same applies to the other electronics units 13c, 13d as well as cuts 17c, 17d and/or 19c, 19d, respectively.

(75) However, in order to increase stability, it may be feasible to either provide cuts 17a to 17d or 19a to 19d.

(76) It is to be noted that dashed lines in FIG. 8A depict foldable substrate foil 24 edges, and solid lines depict cuts 17a to 17d and 19a to 19d, which may be cut foil edges.

(77) Empty strip areas and/or areas between various detector units 12a to 12e and or electronics units 13a to 13d may also be used for electronics, such as e.g. wiring or the like.

(78) FIG. 9A shows schematically a top view of a radiation detector 10, and FIG. 9B shows schematically a detailed view of a part of the radiation detector 10 of FIG. 9A. If not stated otherwise, the radiation detector 10 of FIG. 9A and FIG. 9B comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(79) The radiation detector 10 of FIG. 9A comprises in total nine detector units 12a to 12i, similarly to the radiation detector 10 shown in FIG. 3.

(80) Further, each detector unit 12a to 12i comprises one or more addressing circuits 34 and one or more signal read-out circuits 36.

(81) Detector unit 12a, units 12b, 12d, 12f, 12h as well as 12c, 12e, 12g, 12i may have different pixel size, scintillation devices, addressing circuits 34 and/or signal read-out circuits 36 optimized for low or high dose, low or high kV, low or high resolution applications, as previously described.

(82) Each of the detector units 12a to 12i is interconnected to one of the neighboring detector units 12a to 12i via at least one switch element 38, such as a global data line switch. The switch elements 38 are configured for switchably interconnecting and/or decoupling neighboring detector units 12a to 12i. More specifically, the switch elements 38 may switchably interconnect row addressing lines or column read-out data lines from neighboring detector units 12a to 12i. FIG. 9B shows, by way of example, the interconnection of column read-out lines of detector units 12a and 12b. Each of the detector units 12a to 12i comprises an array 40a, 40b of photosensitive pixels 14 which are arranged in several rows and columns on the substrate foil 24. For clarity reasons the arrays 40a, 40b only comprise three rows and six columns. However, each of the arrays 40a, 40b may comprise as much as 1000 times 1000 pixels 14 or even more.

(83) The arrays 40a, 40b can be interconnected and/or decoupled from each other by means of the switch element 38, which may be a global data line switch and comprise e.g. one TFT element per column for interconnecting/decoupling each column.

(84) The addressing circuits 34 may each comprise an IC as row driver, which addresses multiple rows and/or gate lines of the respective array 40a, 40b of photosensitive pixels 14.

(85) The signal read-out circuits 36 may comprise an IC or ASIC for reading out signals from each column. Further, the read-out circuits 36 may comprise a charge sensitive amplifiers (CSA) 39.

(86) To summarize, detector units 12a to 12i can be decoupled electronically from each other by inserting switch elements 38 in data read-out lines and row driver lines. This enables individual, autonomous operation of each detector units 12a to 12i, avoids crosstalk between detector units 12a to 12i and reduces excessive noise caused by too long data lines

(87) Further, CSAs 39 may comprise bondpads for signal read-out of ICs of the signal read-out circuits 36. For simplicity, TFT elements 16, row driver lines, driver IC's, and pixel circuits are not shown in FIGS. 9A and 9B.

(88) Optionally, ICs can be placed on the substrate foil 24 backside using through-foil-via technology.

(89) FIG. 10 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 10 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(90) The radiation detector 10 comprises three detector units 12a to 12c. At each bending region 30 between detector units 12b and 12a as well as 12a and 12c, the radiation detector is bended by a bending angle 50 of about 60°. Therein, the bending angle 50 is the angle enclosed by two directly neighboring detector units 12b, 12a and 12a, 12c, respectively.

(91) As described in previous figures, the detector units 12a to 12c may be sensitive to radiation of various energies. E.g. detector unit 12a may be an X-ray detector unit and detector units 12b and 12c may be γ-ray detector units.

(92) An impinging direction of photon radiation is indicated in FIG. 10 by the arrow 54, and e.g. a patient position is indicated by object 52. Photons passing through the object 52 are partly absorbed and by means of the detector units 12a to 12c a comprehensive radiation image may be acquired, wherein the detector units 12a to 12c may be positioned according to a geometry of the patient and/or object 52.

(93) FIG. 11 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 11 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(94) The radiation detector 10 of FIG. 11 comprises two detector units 12a, 12b arranged in a bending angle 50 of 90°. Photon radiation may impinge perpendicularly onto each of the detector units 12a, 12b after passing through object 52, as indicated by the double-arrow 54. Again, the detector units 12a, 12b may be sensitive to photons of different energies.

(95) FIG. 12 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 12 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(96) The radiation detector 10 of FIG. 12 comprises two detector units 12a, 12b arranged in a bending angle 50 of 270°. In contrast to the embodiment of FIG. 11 photon radiation may impinge perpendicularly onto each of the detector units 12a, 12b after passing through substrate foil 24, as indicated by the double-arrow 54. Again, the detector units 12a, 12b may be sensitive to photons of different energies.

(97) FIG. 13 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 13 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(98) The radiation detector 10 of FIG. 13 comprises three detector units 12a, 12b, 12c arranged in a bending angle 50 of 180°. Due to the high flexibility of the substrate foil 24, the detector units 12a to 12c can be arranged in a step-like structure, such that each of the detector units 12a to 12c may only have a slightly different distance to an object to be irradiated. Ideally, distance differences should be as small as possible, as they lead to differences in image magnifications for each detector unit 12a, 12b, 12c. However, these can be corrected by image post-processing. Further as can be seen, the substrate foil 24 may be arranged in a Z-like structure in each of the bending regions 30 providing a high degree in flexibility of the radiation detector 10.

(99) FIG. 14 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 14 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(100) The radiation detector 10 comprises in total five detector units 12a to 12e arranged in an arc-like and/or circular geometry. Each of the detector units 12a to 12e has a flat geometry. Radiation may first pass through the substrate foil 24 and then onto the detector units 12a to 12e as depicted by arrow 54. However, any other impinging direction 54 is possible.

(101) As shown, due to the high flexibility of the substrate foil 24 in the bending regions 30, the substrate foil 24 may be folded to a loop-like structure allowing to bring neighboring detector units 12a to 12e closely together for image acquisition.

(102) FIG. 15 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 15 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(103) The radiation detector 10 comprises in total seven detector units 12a to 12g arranged in an arc-like and/or circular geometry. Each of the detector units 12a to 12g has a curved shape and/or a curved outer geometry and/or a curved outer surface. Due to the flexibility of the substrate foil 24 also the substrate foil 24 has a curved shape in regions, where the detector units 12a to 12g are arranged.

(104) The detector units 12a to 12g may be curved in only one spatial direction or dimension, respectively. Alternatively, the detector units 12a to 12g or a part thereof may be curved in two spatial directions, e.g. orthogonal spatial directions, wherein radii of the respective curvatures in both directions may be equal or differ from another. Further, the radiation detector 10 may also comprise a combination of flat detector units 12a to 12g, as shown in FIG. 14, and curved detector units 12a to 12g, as shown in FIG. 15.

(105) Radiation may first pass through the detector units 12a to 12g and then onto the substrate foil 24 as depicted by arrows 54. However, any other impinging direction 54 is possible.

(106) As shown, due to the high flexibility of the substrate foil 24 in the bending regions 30, the substrate foil 24 may be folded to a loop-like structure allowing to bring neighboring detector units 12a to 12g closely together for image acquisition.

(107) FIG. 16 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 16 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(108) The radiation detector 10 comprises in total six detector units 12a to 12f, wherein the detector 10 is folded in the middle of detector 10 in the bending region 30 such that pairs of detector units (12a, 12d; 12b, 12e and 12c, 12f) are arranged back-to-back. E.g. detector units 12a to 12c and detector units 12d to 12f may be sensitive to different radiation energies, for instance for dual energy X-ray imaging applications. The bending angle 50 in FIG. 16 is about 360°.

(109) For dual energy X-ray imaging the detector units 12a to 12c, which are first hit by radiation may have a thinner scintillation device 20 and/or scintillation layer 22 than the detector units 12d to 12f, which are arranged behind the detector units 12a to 12c with respect to the impinging direction 54. This way, detector units 12a to 12c may be more sensitive to low-energy X-rays and detector units 12d to 12f may be more sensitive to high-energy X-rays. Further, detector units 12a to 12c may comprise a different scintillation material than detector units 12d to 12f. Moreover, in order to shield light and/or electromagnetic signals from the scintillation devices 20 of the detector units 12a to 12c and avoid so-called cross-talk, the radiation detector 10 may further comprise one or a plurality of light shields (not shown) arranged on the substrate foil 24.

(110) FIG. 17 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 17 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(111) The radiation detector 10 comprises in total six detector units 12a to 12f, wherein the detector 10 is folded in the middle of detector 10 in the bending region 30. In contrast to FIG. 16, the units 12a to 12f are displaced and/or offset with respect to each other, such that they partly overlap at border regions, and such that pairs of detector units (12a, 12d; 12b, 12e and 12c, 12f) are only partly arranged back-to-back. The configuration of the radiation detector 10 shown in FIG. 17 may be particularly advantageous for very large field-of-view X-ray imaging, such as e.g. whole body imaging and/or spine imaging.

(112) FIG. 18 shows schematically a cross-sectional view of a radiation detector 10 according to an exemplary embodiment. If not stated otherwise, the radiation detector 10 of FIG. 18 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(113) The radiation detector 10 comprises in total five detector units 12a to 12e, wherein units 12b and 12d are displaced and/or offset with respect to the other units 12a, 12c and 12e. As in FIG. 13, the substrate foil 24 is bended and/or folded to a Z-like structure in each bending region 30. The configuration of the radiation detector 10 shown in FIG. 18 may be particularly advantageous for very large field-of-view X-ray imaging, such as e.g. whole body imaging and/or spine imaging.

(114) The geometrical set-ups and/or configurations shown in FIGS. 10 to 18 illustrate the multi-functionality and/multi-modality of the radiation detector 10. Applications may e.g. comprise hybrid X-ray and γ-ray imaging for SIRT (selective internal radio therapy, as e.g. illustrated in FIG. 10), biplane X-ray imaging in IGT (image guided therapy, as e.g. illustrated in FIGS. 11 and 12), Digital Radiology (DR, as e.g. illustrated in FIGS. 13, 17 and 18, Dual-energy DR, as e.g. illustrated in FIG. 16), Computed Tomography (CT) imaging (as e.g. illustrated in FIGS. 14 and 15), Tomosynthesis, Neonatal and/or pediatric imaging (L-shape), wherein no movement of patient may be required for different views, mobile DR applications using a compact portable detector 10, whole-body imaging, trauma, orthopedics and many others.

(115) FIG. 19A shows schematically a cross-sectional view of a radiation detector 10, and FIG. 19B shows schematically a side view of the radiation detector 10 of FIG. 19A.

(116) If not stated otherwise, the radiation detector 10 of FIGS. 19A and 19B comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(117) In FIGS. 19A and 19B, a CT-like ring is formed by means of the radiation detector 10 comprising in total twelve detector units 12, which are arranged in a ring-structure. The radiation detector 10 comprises a support ring 60 for holding the detector units 12 in the ring-structure. The support ring 60 may be positioned by means of tube elements 62 attached via further tube elements 64 to the support ring.

(118) An alternative configuration and/or embodiment would be a half ring.

(119) Further, an adjustable bore size is possible by folding one or more detector units 12 away to the outside of the ring-structure.

(120) Moreover, the detector units 12 of the radiation detector 10 shown FIGS. 19A and 19B may also have a curved shaped, as illustrated in FIG. 15.

(121) FIG. 20A shows schematically a cross-sectional view of a radiation detector 10, FIGS. 20B and 20C each show schematically a detailed view of a part of the radiation detector 10 of 20A according to different embodiments, as explained in the following.

(122) If not stated otherwise, the radiation detector 10 of FIGS. 20A to 20C comprise the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(123) Similarly, to the configuration shown in FIG. 18, the radiation detector 10 of FIG. 20A comprises in total five detector units 12a to 12e, wherein units 12b and 12d are displaced and/or offset with respect to the remaining units 12a, 12c and 12e. The substrate foil 24 is bended and/or folded to a Z-like structure in each bending region 30.

(124) FIG. 20B shows a detailed view of detector units 12a and 12b. Each of the units 12a, 12b comprises a scintillation device 20 with scintillation layer 22 arranged on a photodiode 18 and an array 40a, 40b of photosensitive pixels 14. Further, the addressing circuit 34 and the signal read-out circuit 36 are depicted, which are arranged in the bending region 30 of the substrate foil 24.

(125) As can be seen in FIG. 20B, the substrate foil 24 at the edge 70 of the detector unit 12a is partly overlapping with the detector unit 12b. However, since the substrate foil is rather thin, its X-ray absorbance may be neglected.

(126) In order to provide seamless X-ray detection, the edges 72 of the scintillation devices 20 of detector units 12a, 12b are tapered.

(127) Main criterion for seamless X-ray imaging may be that the photosensitive pixel array 40a of the top detector unit 12a overlaps with the photosensitive pixel array 40b of the bottom detector unit 12b and that in the overlap region at least one of them may be covered with scintillation layer 22 and/or scintillation material. X-ray images of both detector units 12a, 12b can seamlessly be stitched to each other by advanced image processing techniques.

(128) Referring to FIG. 20B, in contrast to the tapered edges 72 of the scintillation devices 20 shown in FIG. 20B, the edges 72 of the scintillation devices 20 of the detector units 12a, 12b shown in FIG. 20C are sharp. A sharp scintillator edge 72 may be preferred above a tapered scintillator edge as the overlap region is smaller and potential image distortions caused by scintillator thickness variations are reduced.

(129) For the sake of completeness, it is to be noted that each of the units 12a, 12b shown in FIG. 20B comprises a scintillation device 20 with scintillation layer 22 arranged on a photodiode 18 and an array 40a, 40b of photosensitive pixels 14. Further, the addressing circuit 34 and the signal read-out circuit 36 are depicted, which are arranged in the bending region 30 of the substrate foil 24

(130) FIG. 21 shows schematically a top view of a radiation detector arrangement 100. The radiation detector arrangement 100 comprises two radiation detectors 10a, 10b as described with reference to the previous figures. If not stated otherwise, each of the radiation detectors 10a, 10b of the radiation detector arrangement 100 of FIG. 21 comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(131) Particularly, each of the radiation detectors 10a, 10b comprises the same elements, features and/or functions as described in FIG. 1.

(132) Amongst others, radiation detector 10a comprises a substrate foil 24a, on which detector units 12a, 12b are arranged in juxtaposition such that the respective scintillation devices 20 are spaced apart from each other by distance 26.

(133) Similarly, radiation detector 10b comprises a substrate foil 24b, on which detector units 12a, 12b are arranged in juxtaposition such that the respective scintillation devices 20 are spaced apart from each other by distance 26.

(134) The two substrate foils 24a, 24b of the radiation detectors 10a, 10b are interconnected with each other at a connecting region 102. The interconnection of the two substrate foils 24a, 24b may comprise a mechanical interconnection of the respective substrate foils 24a, 24b. Accordingly, the substrate foils 24a, 24b may be glued, welded and/or taped together. The substrate foils 24a, 24b may alternatively or additionally be interconnected by a thermofusion process, i.e. by means of a heat seal and compression. A first edge 104a of radiation detector 10a and/or of substrate foil 24a at least partly overlaps with a second edge 104b of radiation detector 10b and/or of substrate foil 24b. The first edge 104a and the second edge 104b may alternatively be arranged flush with respect to each other.

(135) Further, the radiation detectors 10a, 10b may be electronically interconnected, e.g. by means of so-called Through-Foil-Via (TFV), wire bonding and/or by printing conductive lines, e.g. ink-based. This way, an overall size of the radiation detector arrangement 100 as well as a multi-functionality may further be increased.

(136) This way, basically an arbitrary number of radiation detectors 10, 10a, 10b may be interconnected in alternative embodiments of the radiation detector arrangement 100.

(137) FIG. 22 shows schematically a flow chart illustrating steps of a method for producing a radiation detector 10. If not stated otherwise, the radiation detector 10 produced according to the method comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(138) In a first step S1 a substrate foil 24, particularly a single substrate foil 24, is provided and in a second step S2 a plurality of detector units 12a, 12b is provided. The detector units 12a, 12b each comprise a plurality of photosensitive pixels 14, and each comprise at least one scintillation device 20 optically coupled to the plurality of photosensitive pixels 14. Steps S1 and S2 may be performed in arbitrary sequence or simultaneously.

(139) In a further step S3 the detector units 12a, 12b are arranged on the substrate foil 24 in juxtaposition with respect to each other, such that at least two directly adjoining scintillation devices 20 of at least two directly adjoining detector units 12a, 12b are spaced apart from each other by a gap 28, such that the radiation detector 10 is bendable along at least a part of the gap 28.

(140) Optionally, the substrate foil 24 may be cut between the detector units 12a, 12b, i.e. the detector units 12a, 12b may be cut-out, and the detector units 12a, 12b may be laminated, e.g. by gluing and/or welding, to a further large-sized substrate foil in an arbitrary geometrical arrangement with respect to each other.

(141) FIG. 23 schematically illustrates a method for producing a radiation detector 10. FIG. 23 illustrates a detector-on-foil manufacturing process flow. If not stated otherwise, the radiation detector 10 produced according to the method comprises the same features, functions and/or elements as the radiation detectors 10 of previous figures.

(142) In a first step S1 a glass carrier 500 is provided serving as starting substrate.

(143) In a second step S2 a substrate foil 24 is arranged on the glass carrier 500. The substrate foil 24 may be laminated to the glass carrier 500.

(144) In a third step S3 pixels 14 and TFT elements 16 are arranged on the substrate foil 24, e.g. in a TFT backplane fabrication process. The TFT elements 16 may be arranged in an array 40 on the substrate foil 24.

(145) In a fourth step S4 a photodiode 18 is deposited on the pixels 14 and/or on the array 40 of pixels 14.

(146) In a fifth step S5 a scintillator device 20 is arranged on and/or applied to the photodiodes 18. This way, as shown in the exemplary embodiment of FIG. 23, two detector units 12a and 12b are formed.

(147) In a sixth step S6, the substrate foil 24 is delaminated and the radiation detector 10 is basically provided, which may also comprise at least one signal read-out circuit 36 and/or an addressing circuit 34, as shown in previous figures.

(148) Optionally, in a further step electronics may be arranged on the radiation detector 10.

(149) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art and practising the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

(150) In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.