Mammography apparatus including improved radiation detector

Abstract

A mammography apparatus disclosed herein comprises: a radiation source for irradiating a breast of a patient with radiation; and a radiation detector which is disposed opposite the radiation source and generates a radiation image of first energy and a radiation image of second energy on the basis of the radiation that arrives by passing through the breast of the patient. The radiation detector comprises: a first radiation detection unit which includes a first detection panel having a first surface and a second surface parallel to each other and a first light conversion layer provided on the first surface of the first detection panel, and generates a radiation image of the first energy; and a second radiation detection unit which includes a second detection panel having a first surface and a second surface parallel to each other and a second light conversion layer provided on the first surface of the second detection panel, and generates a radiation image of the second energy.

Description

Mammography device including an improved radiation detector

[0001] The present invention relates to a radiation detector and a radiographic imaging device including the same, and more particularly, to a radiation detector capable of obtaining radiographic images of radiation of multiple energies and a radiographic imaging device including the same. The radiographic imaging device may include a mammography device.

[0002]

[0003] Radiation such as X-rays undergo a certain attenuation phenomenon depending on the energy and type of material of the radiation, such as Compton scattering and the photoelectric effect, during the process of penetrating an object.

[0004] Radiography is a radiographic imaging method that utilizes this attenuation phenomenon to project the internal structure of the subject onto a plane. It generates radiation from a radiation source and irradiates the subject, detects the radiation that has passed through the subject, and displays the intensity of the radiation at each location as a radiographic image, such as in gray scale.

[0005] Assuming that the subject of the image is a patient, the intensity of radiation detected by a radiation detector is affected by the radiation attenuation coefficient, which depends on the radiation energy and the characteristics (atomic number, density, etc.) of the constituent substances of the body tissues located along the radiation path. For example, the densities of air, fat, water, and bone in the human body are 0.00129, 0.91, 1, and 1.85 g / cm3, respectively, and the average atomic number also increases in the same order. Therefore, the radiation attenuation coefficient increases in the order of air, fat, water, and bone, and the intensity of radiation detected by a radiation detector decreases according to that order.

[0006] Meanwhile, due to the dependence of this attenuation phenomenon on radiation energy, the energy level of radiation required to obtain the desired diagnostic image may vary depending on the body tissue.

[0007] For example, radiation with a relatively low energy level is suitable for diagnostic imaging of soft tissues such as skin, and radiation with a relatively high energy level is suitable for diagnostic imaging of hard tissues such as bones or teeth.

[0008] However, because the human body is a complex mix of soft and hard tissues, there are clear limitations to the quality of diagnostic images obtained with a given energy level of radiation. In other words, it is difficult to obtain high-quality diagnostic images that highlight specific body tissues (e.g., lesions) with a given energy level of radiation.

[0009] Conventional dual energy techniques utilize the fact that the attenuation coefficient of a material changes depending on the incident X-ray energy. This technique uses two X-ray irradiations to obtain low and high energy images. However, the two X-ray irradiations increase the radiation dose, and since complete separation of the X-ray spectrum is impossible, the accuracy of material separation decreases and the image quality is reduced.

[0010] Additionally, there is a time lag between X-ray images, which can cause motion artifacts due to movement of the organ or subject (e.g., heartbeat, breathing, etc.), which can increase the exposure time and cost of the subject.

[0011] Therefore, there is a need for dual-energy radiography technology that can improve the quality of radiographic images while reducing the radiation exposure of the subject.

[0012]

[0013] [Prior Art Literature]

[0014] [Patent Document]

[0015] (Patent Document 1) Publication No. 10-2016-0079961

[0016] The present invention provides a radiation detector capable of obtaining a radiation image with excellent image uniformity for radiation of first and second energies, and a radiation imaging device including the same.

[0017]

[0018] According to one embodiment of the present invention, a radiation detector includes a first radiation detection unit including a first detection panel having first and second surfaces that are parallel to each other, and a first photoconversion layer provided on the first surface of the first detection panel; and a second radiation detection unit including a second detection panel having first and second surfaces that are parallel to each other, and a second photoconversion layer provided on the first surface of the second detection panel; wherein the first radiation detection unit and the second radiation detection unit can be arranged such that the second surface of the first detection panel and the second surface of the second detection panel face each other.

[0019] The first radiation detection unit can detect radiation of a first energy from radiation incident on a first surface side of the first detection panel, and the second radiation detection unit can detect radiation of a second energy from radiation incident on a second surface side of the second detection panel through the first radiation detection unit.

[0020] The first energy and the second energy may be different.

[0021] The first photoconversion layer and the second photoconversion layer may be made of different materials.

[0022] The device may further include a light blocking layer provided between the first light conversion layer and the second light conversion layer to block light converted in the first light conversion layer from being incident on the second detection panel or light converted in the second light conversion layer from being incident on the first detection panel.

[0023] The first photoconversion layer and the second photoconversion layer may have different thicknesses.

[0024] The first detection panel and the second detection panel each include a pixel array composed of a plurality of pixels, and the pixel array of the first detection panel and the pixel array of the second detection panel may have different sizes of the plurality of pixels.

[0025] At least one of the first photoconversion layer and the second photoconversion layer may include a scintillator that converts radiation into visible light.

[0026] The first photoconversion layer and the second photoconversion layer may be made of cesium iodide (CsI).

[0027] The first photoconversion layer and the second photoconversion layer may be made of gadolinium oxysulfide (GOS).

[0028] At least one of the first photoconversion layer and the second photoconversion layer may include a photoelectric material that generates an electrical signal by radiation.

[0029] Among the first and second photoconversion layers, the photoconversion layer onto which radiation is incident first may include a photoelectric material that generates an electric signal by the radiation, and among the first and second photoconversion layers, the photoconversion layer onto which radiation is incident later may include a scintillation material that converts the radiation into visible light.

[0030] The first photoconversion layer may be made of selenium (Se), and the second photoconversion layer may be made of gadolinium oxysulfide (GOS).

[0031] The first photoconversion layer may be made of selenium (Se), and the second photoconversion layer may be made of cesium iodide (CsI).

[0032] At least one of the first detection panel and the second detection panel may have flexibility.

[0033] It may further include a support member supporting at least one of the first detection panel and the second detection panel.

[0034] It may further include a third light conversion layer provided between the first detection panel and the second detection panel.

[0035] The third light conversion layer may be identical to at least one of the first light conversion layer and the second light conversion layer.

[0036]

[0037] A radiographic apparatus according to another embodiment of the present invention may include: a radiation detector according to one embodiment of the present invention; a radiation source that irradiates radiation toward the radiation detector; and an image processing unit that processes radiation of the first energy detected by the first radiation detection unit and radiation of the second energy detected by the second radiation detection unit to generate a radiation image.

[0038] According to one embodiment of the present disclosure, a mammography device includes a radiation source that irradiates a breast of a patient with radiation, and a radiation detector that is disposed opposite the radiation source and generates a radiation image of a first energy and a radiation image of a second energy based on radiation that has penetrated and reached the breast of the patient, wherein the radiation detector includes a first detection panel having a first surface and a second surface that are parallel to each other, and a first photoconversion layer provided on the first surface of the first detection panel, and includes a first radiation detection unit that generates a radiation image of the first energy, and a second radiation detection unit that includes a second detection panel having a first surface and a second surface that are parallel to each other, and a second photoconversion layer provided on the first surface of the second detection panel, and generates a radiation image of the second energy, wherein the first radiation detection unit and the second radiation detection unit are disposed such that the second surface of the first detection panel and the second surface of the second detection panel face each other.

[0039] According to one embodiment of the present disclosure, a first radiation detection unit of a mammography device detects radiation of a first energy from radiation incident on a first surface side of a first detection panel, and a second radiation detection unit detects radiation of a second energy from radiation incident on a second surface side of a second detection panel through the first radiation detection unit, wherein the first energy and the second energy are different.

[0040] At least one of the first photoconversion layer and the second photoconversion layer of the mammography device according to one embodiment of the present disclosure includes a scintillator that converts radiation into visible light.

[0041] The first photoconversion layer and the second photoconversion layer of the mammography device according to one embodiment of the present disclosure are made of cesium iodide (CsI).

[0042] The first photoconversion layer and the second photoconversion layer of the mammography device according to one embodiment of the present disclosure are made of gadolinium oxysulfide (GOS).

[0043] At least one of the first photoconversion layer and the second photoconversion layer of the mammography device according to one embodiment of the present disclosure includes a photoelectric material that generates an electrical signal by radiation.

[0044] In one embodiment of the present disclosure, among the first and second photoconversion layers of a mammography device, the photoconversion layer onto which radiation is incident first includes a photoelectric material that generates an electric signal by radiation, and among the first and second photoconversion layers, the photoconversion layer onto which radiation is incident later includes a scintillator material that converts radiation into visible light.

[0045] In one embodiment of the present disclosure, the first photoconversion layer of the mammography device is made of selenium (Se), and the second photoconversion layer is made of gadolinium oxysulfide (GOS).

[0046] In one embodiment of the present disclosure, the first photoconversion layer of the mammography device is made of selenium (Se), and the second photoconversion layer is made of cesium iodide (CsI).

[0047] A mammography device according to one embodiment of the present disclosure includes a control unit for controlling the mammography device, wherein the control unit obtains a radiation image of a first energy using a first radiation detection unit, the control unit obtains a radiation image of a second energy using a second radiation detection unit, and obtains a composite image based on the radiation image of the first energy and the radiation image of the second energy.

[0048] A control unit of a mammography device according to one embodiment of the present disclosure obtains a synthetic image by applying a radiation image of a first energy to an image enhancement model to obtain a first corrected image, by applying a radiation image of a second energy to the image enhancement model to obtain a second corrected image, and obtains a synthetic image based on the first corrected image and the second corrected image.

[0049] A control unit of a mammography device according to one embodiment of the present disclosure applies at least one of a first energy radiographic image or a second energy radiographic image to a noise model to obtain noise information, and obtains an improved synthetic image by removing noise from the synthetic image based on the noise information.

[0050] According to one embodiment of the present disclosure, a first energy radiographic image of a mammography device is a lower energy radiographic image than a second energy radiographic image.

[0051]

[0052] According to an embodiment of the present invention, a radiation detector has a first radiation detection unit and a second radiation detection unit arranged so that the second surface of the first detection panel and the second surface of the second detection panel face each other, so that the first detection panel and the second detection panel have excellent thickness uniformity, and the distance between the first photoconversion layer and the second photoconversion layer can be made generally constant, and accordingly, the image uniformity between the first energy radiation image generated through the first radiation detection unit and the second energy radiation image generated through the second radiation detection unit can be improved.

[0053] At this time, a light blocking layer may be provided between the first light conversion layer and the second light conversion layer to prevent light converted in the first light conversion layer from affecting the second detection panel or light converted in the second light conversion layer from affecting the first detection panel.

[0054] And by forming at least one of the first detection panel and the second detection panel into a flexible panel and making it thin, the distance between the first photoconversion layer and the second photoconversion layer can be reduced, and accordingly, the reduction of radiation by the first detection panel and / or the second detection panel can be reduced, and parallax effects such as the difference in magnification between the radiation image of the first energy generated through the first radiation detection unit and the radiation image of the second energy generated through the second radiation detection unit can also be reduced.

[0055]

[0056] FIG. 1 is a schematic cross-sectional view showing a radiation detector according to one embodiment of the present invention.

[0057] FIG. 2 is a schematic cross-sectional view showing a radiation detector including a light blocking layer according to one embodiment of the present invention.

[0058] FIG. 3 is a schematic cross-sectional view showing a radiation detector including first and second light conversion layers having different thicknesses according to one embodiment of the present invention.

[0059] Figure 4 is a schematic cross-sectional view showing modified examples of a radiation detector according to one embodiment of the present invention.

[0060] Figure 5 is a schematic cross-sectional view showing a radiographic apparatus according to another embodiment of the present invention.

[0061] FIG. 6 illustrates a mammography device according to one embodiment of the present disclosure.

[0062] FIG. 7 is a drawing for explaining the operation of a mammography device according to one embodiment of the present disclosure.

[0063] FIG. 8 is a drawing for explaining the operation of a mammography device according to one embodiment of the present disclosure.

[0064] Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In the description, identical reference numerals are assigned to identical components, and the drawings may be partially exaggerated in size to accurately describe the embodiments of the present invention, and identical numerals in the drawings indicate identical elements.

[0065]

[0066] FIG. 1 is a schematic cross-sectional view showing a radiation detector according to one embodiment of the present invention.

[0067] Referring to FIG. 1, a radiation detector (100) according to one embodiment of the present invention may include a first radiation detection unit (110) including a first detection panel (111) having first and second surfaces that are parallel to each other, and a first photoconversion layer (112) provided on the first surface of the first detection panel (111); and a second radiation detection unit (120) including a second detection panel (121) having first and second surfaces that are parallel to each other, and a second photoconversion layer (122) provided on the first surface of the second detection panel (121).

[0068] The first radiation detection unit (110) can detect radiation (10) such as X-rays, and can detect the radiation (10) by converting the image information of the radiation (10) into an electrical signal. For example, the first radiation detection unit (110) can have a first surface and a second surface that face each other, and the surface of the first surface and the second surface facing the radiation source (210) can be a radiation-transmitting surface, and the radiation (10) incident on the radiation-transmitting surface can be converted into an electrical signal that can be processed as an image signal. At this time, the first radiation detection unit (110) can detect radiation of a first energy (or energy band).

[0069] Here, the first radiation detection unit (110) may include a first detection panel (111) having a first side and a second side that are parallel to each other, and a first photoconversion layer (112) provided on the first side of the first detection panel (111). The first detection panel (111) may have a first side and a second side that are parallel to each other (or opposite to each other), and the flatness of the first side and the second side may be excellent, and the thickness may be uniform overall. For example, the first detection panel (111) may include a pixel circuit board, and the pixel circuit board may include a thin film transistor (TFT), and in the case of an indirect method, may include a light-receiving element such as a photodiode that detects light converted from a first light conversion layer (112) such as a scintillator and converts it into an electric signal, and the light-receiving element may be an amorphous silicon (α-Si) photodiode circuit.

[0070] The first photoconversion layer (112) may be provided on the first surface of the first detection panel (111), and may be a photoconductive layer (direct method) composed of selenium (Se) such as amorphous selenium (α-Se), cadmium telluride (CdTe) such as crystalline cadmium telluride (crystalloid CdTe), crystalline cadmium telluride compounds, or may be a photoconductive layer (direct method) composed of cesium iodide (CsI), thallium (Tl)-doped cesium iodide (CsI(Tl)), gadolinium oxysulfide (GOS, Gd x O y S z or Gadox, Gd2O2S) or calcium tungsten oxide (CaWO x ) may be a scintillator (layer) (indirect method) composed of a light source (10) and the like. In the case of a direct method that directly detects an electrical signal (or electric signal) generated by radiation (10) that has passed through a subject (20), the photoconductive layer that exhibits photoconductivity and directly converts radiation (10) into an electrical signal through a photoelectric effect may be used as the first light conversion layer (112), and in the case of the indirect method that converts radiation (10) into light such as visible light (ray) in a fluorescent layer such as a scintillator and then converts the converted light back into an electrical signal, the scintillator (layer) that converts radiation (10) into optical photons (i.e., light) may be used as the first light conversion layer (112).

[0071] The second radiation detection unit (120) can also detect radiation (10), and can detect the radiation (10) by converting the image information of the radiation (10) into an electrical signal. For example, the second radiation detection unit (120) can have a first surface and a second surface that face each other, and the surface of the first surface and the second surface facing the radiation source (210) can be a radiation-transmitting surface, and can convert radiation (10) incident on the radiation-transmitting surface into an electrical signal that can be processed as an image signal. At this time, the second radiation detection unit (120) can detect radiation of a second energy (or energy band), and can also detect radiation that has passed through the first radiation detection unit (110).

[0072] Here, the second radiation detection unit (120) may include a second detection panel (121) having a first side and a second side that are parallel to each other, and a second photoconversion layer (122) provided on the first side of the second detection panel (121). The second detection panel (121) may have a first side and a second side that are parallel to each other, and the flatness of the first side and the second side may be excellent, and the thickness may be uniform overall. For example, the second detection panel (121) may also include a pixel circuit board, and the pixel circuit board may include a thin film transistor (TFT), and in the case of the indirect method, similar to the first detection panel (111), may include a light-receiving element such as a photodiode that detects light converted from a second light conversion layer (122) such as a scintillator and converts it into an electric signal, and the light-receiving element may be an amorphous silicon (α-Si) photodiode circuit.

[0073] The second photoconversion layer (122) may be provided on the first surface of the second detection panel (121), and, like the first photoconversion layer (112), depending on the radiation detection method selected from the direct method and the indirect method, may be a photoconductive layer (direct method) composed of selenium (Se) such as amorphous selenium (α-Se), cadmium telluride (CdTe) such as crystalline cadmium telluride (crystalloid CdTe), crystalline cadmium telluride compounds, or cesium iodide (CsI), thallium (Tl)-doped cesium iodide (CsI(Tl)), gadolinium oxysulfide (GOS or Gadox), calcium tungsten oxide (CaWO). x ) may be a scintillator (layer) (indirect method) composed of a plurality of layers.

[0074] And the first photoconversion layer (112) and the second photoconversion layer (122) may not be flat, and may not be flatter than the first detection panel (111) and the second detection panel (121), and the thickness may not be uniform overall, so that the thickness may differ for each region (or location). For example, the scintillator (layer) made of cesium iodide (CsI), which is mainly used as the first photoconversion layer (112) and / or the second photoconversion layer (122), is composed of cylindrical crystals, and may not be flat due to the cesium iodide (CsI) deposition process.

[0075] Here, the first radiation detection unit (110) and the second radiation detection unit (120) may be arranged so that the second surface of the first detection panel (111) and the second surface of the second detection panel (121) face each other, the second surface of the first detection panel (111) and the second surface of the second detection panel (121) may be in (direct) contact, and another configuration such as a light blocking layer (131) may be interposed between the second surface of the first detection panel (111) and the second surface of the second detection panel (121). That is, the first radiation detection unit (110) and the second radiation detection unit (120) can be arranged symmetrically so that the second surface of the first detection panel (111) and the second surface of the second detection panel (121) face each other, and the first photoconversion layer (112) and the first detection panel (111) can be arranged symmetrically with the second detection panel (121) and the second photoconversion layer (122) centered between the second surface of the first detection panel (111) and the second surface of the second detection panel (121). Through this, a radiation detector (100) can be formed in which radiation (10) is incident (front incident) on the first radiation detection unit (110) from the first surface side of the first detection panel (111) and radiation (10) is incident (back incident) on the second radiation detection unit (120) from the second surface side of the second detection panel (121).

[0076] The first detection panel (111) and the second detection panel (121) have excellent thickness uniformity, so that when the first radiation detection unit (110) and the second radiation detection unit (120) are arranged symmetrically so that the second surface of the first detection panel (111) and the second surface of the second detection panel (121) face each other, the distance between the first photoconversion layer (112) and the second photoconversion layer (122) (and / or the distance between the first radiation detection unit and the second radiation detection unit) can be made uniform overall (or generally), and accordingly, the image uniformity between the radiation image of the first energy generated through the first radiation detection unit (110) and the radiation image of the second energy generated through the second radiation detection unit (120) can be improved.

[0077] In addition, for the image uniformity between the radiation image of the first energy and the radiation image of the second energy, the alignment between the pixels of the first detection panel (111) and the second detection panel (121) is important. In the case where the second surface of the first detection panel (111) and the second surface of the second detection panel (121) are opposite to each other and the first radiation detection unit (110) and the second radiation detection unit (120) are symmetrically arranged, the distance between the first detection panel (111) and the second detection panel (121) can be shortened, so that it is easy to align the centers between the pixels of the first detection panel (111) and the second detection panel (121), and the distance between the pixels of the first detection panel (111) and the second detection panel (121) is also uniform overall, so that the pixels of the first detection panel (111) and the second The pixels of the detection panel (121) may be overlapped in parallel. This can further improve the image uniformity between the radiation image of the first energy and the radiation image of the second energy.

[0078] Meanwhile, when the first detection panel (111) and / or the second detection panel (121) include a transparent material, alignment between the pixels of the first detection panel (111) and the second detection panel (121) can be facilitated, and the pixels of the first detection panel (111) and the second detection panel (121) can be aligned while actually confirming (or viewing) the pixel positions of the first detection panel (111) and the second detection panel (121). At this time, the pixel positions of the first detection panel (111) and the second detection panel (121) can be confirmed by actual measurement with an optical sensor such as a camera.

[0079] The first radiation detection unit (110) and the second radiation detection unit (120) can be arranged (or stacked) in the direction of radiation (10), and the first radiation detection unit (110) can detect radiation of a first energy from radiation (10) incident on the first surface side of the first detection panel (111), and the second radiation detection unit (120) can detect radiation of a second energy from radiation incident on the second surface side of the second detection panel (121) through the first radiation detection unit (110).

[0080] For example, a radiation source (210) may be provided on the first surface side of the first detection panel (111) to irradiate radiation (10) toward the first radiation detection unit (110), and the radiation (10) may be incident on the first light conversion layer (112) and at least a portion thereof may be converted, and among the remaining portions of the radiation (10), radiation that has passed through (or transmitted) the first radiation detection unit (110) may pass through the second detection panel (121) and reach the second light conversion layer (122) and be converted. That is, the radiation (10) irradiated from the radiation source (210) may be incident on the first light conversion layer (112), the first detection panel (111), the second detection panel (121), and the second light conversion layer (122) in that order (or in that sequence).

[0081] When the first radiation detection unit (110) and the second radiation detection unit (120) are arranged in the direction of the radiation (10), the distances between the first radiation detection unit (110) and the second radiation detection unit (120) and the radiation source (210) become different, and thus a difference in magnification occurs between the radiation image generated by the first radiation detection unit (110) and the radiation image generated by the second radiation detection unit (120). At this time, when the distance between the first radiation detection unit (110) and the second radiation detection unit (120) (for example, the distance between the first photoconversion layer and the second photoconversion layer) changes for each position (or area), a deviation occurs in the magnification difference for each position.

[0082] The scintillator (layer) of the direct deposition method mainly used as the first photoconversion layer (112) and / or the second photoconversion layer (122) has a thickness deviation at each position (relatively) and may exhibit different magnifications (or magnification deviations) at each position, which causes a deviation in the magnification difference between the radiation image generated from the first radiation detection unit (110) and the radiation image generated from the second radiation detection unit (120), and errors can easily occur during image registration work for matching the two images having the deviation in the magnification difference, which may cause image artifacts. If the image registration between the two images does not match well due to the deviation in the magnification difference and an image artifact occurs, the performance of the (diagnostic) image obtained by subtracting and / or synthesizing the two images is reduced.

[0083] However, since the first detection panel (111) and the second detection panel (121) have (relatively) very uniform thicknesses, when the first radiation detection unit (110) and the second radiation detection unit (120) are arranged back-to-back so that the second surface of the first detection panel (111) and the second surface of the second detection panel (121) face each other, the distance between the first radiation detection unit (110) and the second radiation detection unit (120) (for example, the distance between the first photoconversion layer and the second photoconversion layer) can be constant in the entire detection area (or overall), and accordingly, the deviation in the magnification difference between the radiation image generated by the first radiation detection unit (110) and the radiation image generated by the second radiation detection unit (120) can not occur, and the image uniformity between the two radiation images can be improved. Accordingly, image alignment can be facilitated between the radiation image generated from the first radiation detection unit (110) and the radiation image generated from the second radiation detection unit (120), so that a clear subtraction image and / or composite image can be obtained without deterioration in image quality using the two radiation images, and the quality of the (diagnostic) image can be improved, thereby improving the accuracy of image diagnosis.

[0084] Meanwhile, since the first detection panel (111) and the second detection panel (121) have first surfaces with excellent flatness, when the first photoconversion layer (112) and the second photoconversion layer (122) are deposited on the first surface of the first detection panel (111) and the first surface of the second detection panel (121), respectively, the deposition thickness of the first photoconversion layer (112) and the second photoconversion layer (122) can be formed to be constant, and can also be controlled to a desired deposition thickness. For example, the first detection panel (111) and the second detection panel (121) may have a constant size, such as thickness and area, and the deposition thickness, area, position, etc. of the first photoconversion layer (112) and the second photoconversion layer (122) may be perfectly shifted and controlled according to a desired (or desired) specification based on information about the thickness, area, etc. of the constant first detection panel (111) and the second detection panel (121). Accordingly, the accurate deposition thickness of the first photoconversion layer (112) and the second photoconversion layer (122) according to the specification can be uniformly formed and manufactured, and the image quality can be increased when matching the radiation image generated from the first radiation detection unit (110) and the radiation image generated from the second radiation detection unit (120).

[0085] The first energy and the second energy may be different. That is, the radiation detector (100) of the present invention may be a dual energy radiation detector and may acquire radiation images of multiple energies (e.g., dual energy) (bands). To this end, the first radiation detection unit (110) and the second radiation detection unit (120) may detect radiation of different (or different) energies (or energy bands). At this time, the first radiation detection unit (110) may detect radiation of the first energy, and the second radiation detection unit (120) may detect radiation of the second energy different from the first energy. For example, the first radiation detection unit (110) and the second radiation detection unit (120) can be completely overlapped to obtain a dual-energy radiation image, and the dual-energy radiation image can be obtained in an area equivalent to the radiation-transmitting surface area of ​​the first radiation detection unit (110) and the second radiation detection unit (120).

[0086] At this time, the first detection panel (111) and the second detection panel (121) may be formed of a radiation-transparent material, and radiation (e.g., high-energy radiation) that is incident on the first radiation detection unit (110) and passes (or transmits) through the first detection panel (111) may transmit through the second detection panel (121) and be transmitted to the second light conversion layer (122), and the transmitted radiation may be converted in the second light conversion layer (122). Through this, by detecting radiation of different energies in the first radiation detection unit (110) and the second radiation detection unit (120), a dual-energy radiation image may be obtained.

[0087] The first radiation detection unit (110) and the second radiation detection unit (120) can detect radiation of different energies in an overlapping area, obtain a dual-energy radiation image for the overlapping area, and perform dual-energy photography with a single radiation (10) irradiation.

[0088] Here, when the first radiation detection unit (110) is positioned closer to the radiation source (210) than the second radiation detection unit (120), the first radiation detection unit (110) can detect and filter (or remove) low-energy radiation, thereby transmitting only high-energy radiation to the second radiation detection unit (120), and the second radiation detection unit (120) can detect high-energy radiation transmitted through the first radiation detection unit (110).

[0089] At this time, the first photoconversion layer (112) and the second photoconversion layer (122) may be different. In order for the energy difference (e.g., difference in images of bone and soft tissue) to be clearly shown between the radiation image of the first energy (e.g., low energy) acquired by the first radiation detection unit (110) and the radiation image of the second energy (e.g., high energy) acquired by the second radiation detection unit (120), the first radiation detection unit (110) must effectively detect the radiation (only) of the first energy, and the second radiation detection unit (120) must effectively detect the radiation (only) of the second energy.

[0090] Depending on the material and / or thickness of the first photoconversion layer (112) and the second photoconversion layer (122), the energy of radiation absorbed and / or converted by the first photoconversion layer (112) and the second photoconversion layer (122) may vary, and accordingly, the radiation energy detectable by the first radiation detection unit (110) and the second radiation detection unit (120) may vary. Accordingly, the first photoconversion layer (112) may be formed of a material and / or thickness that absorbs and / or converts the first energy well, and the second photoconversion layer (122) may be formed of a material and / or thickness that absorbs and / or converts the second energy well, and since the first radiation detection unit (110) and the second radiation detection unit (120) detect different radiations of the first energy and the second energy, respectively, the first photoconversion layer (112) and the second photoconversion layer (122) may be different.

[0091] For example, the first photoconversion layer (112) and the second photoconversion layer (122) may be made of different materials, and the energy characteristics of detectable radiation may vary depending on the materials of the first photoconversion layer (112) and the second photoconversion layer (122). When the first radiation detection unit (110) detects low-energy radiation, the first photoconversion layer (112) may be formed of cesium iodide (CsI) which has high sensitivity to low-energy radiation, and when the second radiation detection unit (120) detects high-energy radiation, the second photoconversion layer (122) may be formed of gadolinium oxysulfide (GOS) which has high sensitivity to high-energy radiation.

[0092] Meanwhile, the first radiation detection unit (110) is formed in the direct manner and the second radiation detection unit (120) is formed in the indirect manner, so that the materials of the first photoconversion layer (112) and the second photoconversion layer (122) may be different.

[0093] FIG. 2 is a schematic cross-sectional view showing a radiation detector including a light blocking layer according to one embodiment of the present invention.

[0094] Referring to FIG. 2, the radiation detector (100) according to the present invention may further include a light blocking layer (131) provided between the first light conversion layer (112) and the second light conversion layer (122) to block light converted in the first light conversion layer (112) from being incident on the second detection panel (121) or light converted in the second light conversion layer (122) from being incident on the first detection panel (111).

[0095] The light blocking layer (131) is provided between the first light conversion layer (112) and the second light conversion layer (122) to block light (e.g., visible light) converted (or generated) in the first light conversion layer (112) from being incident on the second detection panel (121), or light converted in the second light conversion layer (122) from being incident on the first detection panel (111). For example, the light blocking layer (131) may be interposed between the first detection panel (111) and the second detection panel (121), and may block light converted in the first light conversion layer (112) and incident on the second detection panel (121), and may block light converted in the second light conversion layer (122) and incident on the first detection panel (111). Accordingly, the light converted in the first light conversion layer (112) can be made to be incident only on the first detection panel (111) and not incident on the second detection panel (121), and the light converted in the second light conversion layer (122) can be made to be incident only on the second detection panel (121) and not incident on the first detection panel (111). Here, the light blocking layer (131) can be radiation transparent, block visible light, and transmit at least some of the radiation to transmit the radiation (10) between the first radiation detection unit (110) and the second radiation detection unit (120).

[0096] The first detection panel (111) and the second detection panel (121) may be made of a transparent material so that no loss of radiation (10) occurs in the first detection panel (111) and / or the second detection panel (121), and thus, the light converted in the first photoconversion layer (112) and the second photoconversion layer (122), respectively, may affect the detection panels (121, 111) of other radiation detection units (120, 110) than the detection panels (111, 121) of the corresponding (or included) radiation detection units (110, 120) (for example, detection panels that are not deposited). Accordingly, a light blocking layer (131) is formed between the first detection panel (111) and the second detection panel (121), thereby preventing the light converted in the first light conversion layer (112) and the second light conversion layer (122) from affecting the detection panels (121, 111) of the other radiation detection units (120, 110).

[0097] That is, the light blocking layer (131) may be arranged between the first detection panel (111) and the second detection panel (121) to prevent crossover or interference of light converted by the first light conversion layer (112) and the second light conversion layer (122) with respect to the detection panels (121, 111) of the other radiation detection units (120, 110), and may block light transmitted from the light conversion layers (122, 112) of the other radiation detection units (120, 110) between the first detection panel (111) and the second detection panel (121), and may have the effect of eliminating signal interference between the first detection panel (111) and the second detection panel (121). At this time, the light blocking layer (131) may be a light absorption blocking layer that absorbs and blocks visible light (rays).

[0098] For example, the light-blocking layer (131) may be composed of an organic photoelectric conversion film made of an organic photoelectric conversion material, such as poron or high-density (poly)urethane. In addition, the light-blocking layer (131) may be a hydrophilic colloid layer of gelatin containing a mixture of microcrystalline crossover-reducing dyes, such as arylidene dyes, in a 1:1 weight ratio.

[0099] Meanwhile, the light blocking layer (131) may also function as a radiation (e.g., X-ray) energy filter, and may absorb and remove at least some energy (e.g., the first energy) from the radiation (10). For example, the light blocking layer (131) may absorb and remove low-energy (or the first energy) radiation, thereby transmitting (or providing) high-energy (or the second energy) radiation (only) to the second radiation detection unit (120). The light blocking layer (131) may include a metal or alloy as a radiation energy filter, and may include one or a combination of two or more of copper (Cu), aluminum (Al), silver (Ag), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), cadmium (Cd), tin (Sn), barium (Ba), tungsten (W), tantalum (Ta), gold (Au), and lead (Pb). In addition, the light blocking layer (131) may also block noise between the first detection panel (111) and the second detection panel (121).

[0100] Accordingly, the radiation detector (100) according to the present invention can prevent light converted in the first light conversion layer (112) from affecting the second detection panel (121) or light converted in the second light conversion layer (122) from affecting the first detection panel (111) by providing a light blocking layer (131) between the first light conversion layer (112) and the second light conversion layer (122) by providing a light blocking layer (131) between the first light conversion layer (112) and the second light conversion layer (122). Accordingly, the radiation detector (100) can have the effect of eliminating signal interference between the first detection panel (111) and the second detection panel (121), and can improve the image quality of radiation images generated by the first radiation detection unit (110) and the second radiation detection unit (120).

[0101] FIG. 3 is a schematic cross-sectional view showing a radiation detector including first and second light conversion layers having different thicknesses according to one embodiment of the present invention.

[0102] Referring to FIG. 3, the first photoconversion layer (112) and the second photoconversion layer (122) may have different thicknesses, and the energy (or energy band) of detectable radiation may vary depending on the thickness of the first photoconversion layer (112) and the second photoconversion layer (122). For example, when the first radiation detection unit (110) detects low-energy radiation, the first photoconversion layer (112) may be formed (relatively) thin so as to detect low-energy radiation well, and when the second radiation detection unit (120) detects high-energy radiation, the second photoconversion layer (122) may be formed (relatively) thick so as to detect high-energy radiation well.

[0103] In addition, since the amount of light emitted (i.e., the amount of radiation converted into light in the first light conversion layer) increases when the first light conversion layer (112) becomes thicker, there are few (or no) obstacles (e.g., radiation absorbers, etc.) between it and the radiation source (210), and the first light conversion layer (112) with a (relatively) high absorption rate is made thinner than the second light conversion layer (122), which may be better in terms of image quality and sensitivity.

[0104] And the first detection panel (111) and the second detection panel (121) may each include a pixel array composed of a plurality of pixels, and the pixel array of the first detection panel (111) and the pixel array of the second detection panel (121) may differ in at least one of the sizes and intervals of the plurality of pixels. The first detection panel (111) and the second detection panel (121) may each include a pixel array composed of a plurality of pixels, and may be a flat panel in which the plurality of pixels are arranged in a matrix form along a two-dimensional plane.

[0105] Here, the pixel array of the first detection panel (111) and the pixel array of the second detection panel (121) may differ in at least one of the sizes and spacings of the plurality of pixels, and the sizes and / or spacings of the plurality of pixels of the second detection panel (121) may be adjusted (or adjusted) according to the difference in magnification due to the difference in distances from the radiation source (210) of the first detection panel (111) and the second detection panel (121), and the sizes and / or spacings of the plurality of pixels may be made different between the pixel array of the first detection panel (111) and the pixel array of the second detection panel (121). In addition, depending on the size of the plurality of pixels, each of the first radiation detection unit (110) and the second radiation detection unit (120) can be configured as sensitivity-centered or image quality-centered. When the size of each pixel increases and the light-receiving area increases, the sensitivity can be improved and the center of sensitivity can be achieved, and when the size of each pixel decreases and the light-receiving area decreases, the image quality can be improved and the center of image quality can be achieved. For example, the first radiation detection unit (110) having a first photoconversion layer (112) with a (relatively) high absorption rate can be configured as image quality-centered, and when there are (relatively) many obstacles between it and the radiation source (210) and the second radiation detection unit (120) having a second photoconversion layer (122) with a (relatively) low absorption rate can be configured as sensitivity-centered. At this time, the size of the plurality of pixels in the pixel array of the first detection panel (111) may be (relatively) smaller than the plurality of pixels in the pixel array of the second detection panel (121) so that the first radiation detection unit (110) becomes the center of image quality, and the size of the plurality of pixels in the pixel array of the second detection panel (121) may be (relatively) larger than the plurality of pixels in the pixel array of the first detection panel (111) so that the second radiation detection unit (120) becomes the center of sensitivity.

[0106] FIG. 4 is a schematic cross-sectional view showing modified examples of a radiation detector according to an embodiment of the present invention, FIG. 4(a) shows a radiation detector including a first direct-type radiation detection unit and a second indirect-type radiation detection unit, FIG. 4(b) shows a radiation detector in which a support member is provided between the first direct-type radiation detection unit and the second direct-type radiation detection unit, and FIG. 4(c) shows a radiation detector in which a third photoconversion layer is provided between the first indirect-type radiation detection unit and the second indirect-type radiation detection unit.

[0107] Referring to FIG. 4, at least one of the first photoconversion layer (112) and the second photoconversion layer (122) may include a scintillator that converts radiation (10) into visible light, and the radiation detection unit (110a or 120a) having a photoconversion layer (112a or 122a) among the first photoconversion layer (112) and the second photoconversion layer (122) that includes a scintillator that converts radiation (10) into visible light may be the indirect method of converting the visible light converted by the scintillator into an electrical signal again. Here, the scintillator may include a rare earth sulfide doped with a rare earth activator, such as Gd2O2S:Tb, Gd2O2S:Eu, Gd2O3:Eu, La2O2S:Tb, La2O2S, Y2O2S:Tb, CsI:Tl, CsI:Na, CsBr:Tl, NaI:Tl, CaWO4, CaWO4:Tb, BaFBr:Eu, BaFCl:Eu, BaSO4:Eu, BaSrSO4, BaPbSO4, BaAl 12 O 19 :Mn, BaMgAl 10 O 17:Eu, Zn2SiO4:Mn, (Zn,Cd)S:Ag, LaOBr, LaOBr:Tm, Lu2O2S:Eu, Lu2O2S:Tb, LuTaO4, HfO2:Ti, HfGeO4:Ti, YTaO4, YTaO4:Gd, YTaO4:Nb, Y2O3:Eu, YBO3:Eu, YBO3:Tb, (Y,Gd)BO3:Eu, or a combination thereof.

[0108] For example, both the first photoconversion layer (112) and the second photoconversion layer (122) may be made of cesium iodide (CsI), and both the first photoconversion layer (112) and the second photoconversion layer (122) may be made of gadolinium oxysulfide (GOS). When the first photoconversion layer (112) and the second photoconversion layer (122) are made of the same material, the thicknesses of the first photoconversion layer (112) and the second photoconversion layer (122) may be different, and the photoconversion characteristics of the first photoconversion layer (112) and the second photoconversion layer (122) may be (almost) the same, so that the image alignment may be facilitated and the quality of the composite image may be improved.

[0109] In addition, at least one of the first photoconversion layer (112) and the second photoconversion layer (122) may include a photoelectric material that generates an electric signal by radiation (10), and the radiation detection unit (110b or 120b) having a photoconversion layer (112b or 122b) including a photoelectric material that generates an electric signal by radiation (10) among the first photoconversion layer (112) and the second photoconversion layer (122) may be a direct method that directly detects an electric signal generated by radiation (10) that has passed through a subject (20) by directly converting radiation (10) into an electric signal through a photoelectric effect by the photoelectric material exhibiting photoconductivity. Here, the photoelectric material may include selenium (Se) such as amorphous selenium (α-Se), cadmium telluride (CdTe) such as crystalline cadmium telluride (crystalloid CdTe), crystalline cadmium telluride compounds, etc.

[0110] The first radiation detection unit (110) and the second radiation detection unit (120) may both be configured in the indirect manner, or may both be configured in the direct manner, or may be configured in a hybrid manner consisting of the first radiation detection unit (110b) of the direct manner and the second radiation detection unit (120a) of the indirect manner, or the first radiation detection unit (110a) of the indirect manner and the second radiation detection unit (120b) of the direct manner. In order to enable the first radiation detection unit (110) to detect low-energy radiation well and the second radiation detection unit (120) to detect high-energy radiation well, the first photoconversion layer (112) and the second photoconversion layer (122) may each selectively include the scintillation material or the photoelectric material, so that the first radiation detection unit (110) and the second radiation detection unit (120) may each be configured in the indirect manner or the direct manner. Through this, the radiation detector (100) according to the present invention can be configured in various ways, such as indirect-indirect, direct-direct, or direct-indirect hybrid methods (types), with the first radiation detection unit (110) and the second radiation detection unit (120).

[0111] For example, if the first photoconversion layer (112) (closer) to the radiation source (210) is made of cesium iodide (CsI), since cesium iodide (CsI) has absorption characteristics for a specific wavelength range, the first photoconversion layer (112) can also function as a radiation energy filter, and the first photoconversion layer (112) of cesium iodide (CsI) and the second photoconversion layer (122) of gadolinium oxysulfide (GOS) can be configured to have a structure that prioritizes low-energy upper image quality and low-dose lower sensitivity.

[0112] In addition, the radiation detector (100) can be configured as a hybrid type that combines direct and indirect methods. In this case, the direct method and the indirect method can be combined to enable effective separation of low-energy radiation and high-energy radiation without a separate radiation energy filter.

[0113] This hybrid structure can enable improved spatial resolution and dose efficiency compared to those achieved with either the direct or indirect method alone, thereby enhancing sharpness. Furthermore, it can take advantage of the advantages of both the direct and indirect methods while minimizing their respective disadvantages, and the direct interaction of radiation with selenium (Se) can help maintain image sharpness and overcome electronic noise at high spatial frequencies. On the other hand, the radiation signal from the scintillator (layer) appears blurry compared to the radiation signal from amorphous selenium (α-Se), but its high absorption efficiency can increase the overall detector signal and improve low-dose performance.

[0114] That is, when the radiation detector (100) is configured as a hybrid type using both direct and indirect methods, both the first radiation detection unit (110) and the second radiation detection unit (120) can exhibit improved dose efficiency compared to using only the direct method, and both the first radiation detection unit (110) and the second radiation detection unit (120) can exhibit better spatial resolution compared to using only the indirect method, and through high absorption efficiency combined with high spatial resolution, it is possible to provide further improved quantum efficiency and improved images (especially) for fine details and low contrast objects.

[0115] For example, among the first photoconversion layer (112) and the second photoconversion layer (122), the photoconversion layer (112 or 122) onto which radiation (10) is incident first may include a photoelectric material that generates an electric signal by radiation (10), and among the first photoconversion layer (112) and the second photoconversion layer (122 or 112) onto which radiation (10) is incident secondarily may include a scintillation material that converts radiation (10) into visible light. That is, by including the photoelectric material in the photoconversion layer (112b or 122b) of the radiation detection unit (110b or 120b) (closer) to the radiation source (210) and including the scintillation material in the photoconversion layer (122a or 112a) of the radiation detection unit (120a or 110a) (relatively) far from the radiation source (210), the near radiation detection unit (110b or 120b) can be configured in the direct manner, and the far radiation detection unit (120a or 110a) can be configured in the indirect manner. When the near radiation detection unit (110 or 120) is configured in the direct manner and the photoconversion layer (112 or 122) is formed of amorphous selenium (α-Se), low-energy radiation can be detected well and high-energy radiation can be transmitted well. And when the above-mentioned distant radiation detection unit (120 or 110) is configured in the above-mentioned indirect manner and the photoconversion layer (122 or 112) is formed of gadolinium oxysulfide (GOS) which has high sensitivity to high-energy radiation, high-energy radiation can be detected well. However, this is not particularly limited, and the first photoconversion layer (112) and the second photoconversion layer (122) can be configured in various ways.

[0116] At this time, the first photoconversion layer (112) may be made of selenium (Se), and the second photoconversion layer (122) may be made of gadolinium oxysulfide (GOS). In this case, the first radiation detection unit (110) can detect low-energy radiation well by the first photoconversion layer (112), and the second radiation detection unit (120) can detect high-energy radiation well by the second photoconversion layer (122).

[0117] Meanwhile, the first photoconversion layer (112) may be made of selenium (Se), and the second photoconversion layer (122) may be made of cesium iodide (CsI). Since selenium (Se) has better sensitivity to lower (low) energy radiation than cesium iodide (CsI), the first radiation detection unit (110) can detect relatively low (low) energy radiation by the first photoconversion layer (112) made of selenium (Se), and the second radiation detection unit (120) can detect relatively high (low) energy radiation by the second photoconversion layer (122) made of cesium iodide (CsI). Through this, the first radiation detection unit (110) and the second radiation detection unit (120) can detect radiation of different energies (i.e., the first energy and the second energy).

[0118] Here, at least one of the first detection panel (111) and the second detection panel (121) may have flexibility. The first detection panel (111) and the second detection panel (121) may use a highly heat-resistant substrate such as a semiconductor substrate, a quartz substrate, and a glass substrate as a substrate of a thin film transistor (TFT), but are not limited thereto, and may have flexibility such as using a flexible substrate such as plastic, aramid, bio nano fiber, or using a flexible panel. A panel having such flexibility can well transmit high-energy radiation and well absorb low-energy radiation, thereby improving the sensitivity of the distant radiation detection unit (e.g., the second radiation detection unit) to high-energy radiation. In addition, the panel having the above flexibility can be formed thinly, so that the distance between the first light conversion layer (112) and the second light conversion layer (122) can be reduced.

[0119] Accordingly, the radiation detector (100) according to the present invention can reduce the distance between the first photoconversion layer (112) and the second photoconversion layer (122) by forming at least one of the first detection panel (111) and the second detection panel (121) as a flexible panel to make it thin, and thus the reduction of radiation (10) by the first detection panel (111) and / or the second detection panel (121) can be reduced, and the parallax effect such as the difference in magnification between the radiation image of the first energy generated through the first radiation detection unit (110) and the radiation image of the second energy generated through the second radiation detection unit (120) can also be reduced.

[0120] The radiation detector (100) according to the present invention may further include a support member (140) that supports at least one of the first detection panel (111) and the second detection panel (121).

[0121] The support member (140) can support at least one of the first detection panel (111) and the second detection panel (121), and can support the detection panel (111 or 121) having flexibility. The detection panel (111 or 121) having flexibility can have different flatness depending on the object it comes into contact with, and accordingly, the flatness of the detection panel (111 or 121) having flexibility can be secured through the support member (140), and the thickness of the detection panel (111 or 121) having flexibility can be maintained uniformly overall (or as a whole), so that the distance between the first light conversion layer (112) and the second light conversion layer (122) can be made uniform overall.

[0122] The radiation detector (100) according to the present invention may further include a third light conversion layer (132) provided between the first detection panel (111) and the second detection panel (121).

[0123] The third light conversion layer (132) may be provided between the first detection panel (111) and the second detection panel (121), and may serve as a radiation energy filter that blocks low-energy radiation (e.g., the first energy) and transmits high-energy radiation (e.g., the second energy), or may be used to convert low-energy radiation or high-energy radiation to auxiliary radiation to the first light conversion layer (112) or the second light conversion layer (122) to process an image signal (or an electrical signal) in the first detection panel (111) or the second detection panel (121).

[0124] At this time, the third photoconversion layer (132) may be identical to at least one of the first photoconversion layer (112) and the second photoconversion layer (122), and may auxiliary convert radiation of the second energy or the first energy to the same photoconversion layer (122 or 112) to generate the electric signal for the image signal processing. At this time, the sum of the thickness of the same photoconversion layer (122 or 112) and the thickness of the third photoconversion layer (132) may be greater than or equal to the thickness of the remaining (other) photoconversion layer (112 or 122).

[0125] For example, the third light conversion layer (132) may be made of the same material as the second light conversion layer (122) and may convert radiation of the second energy. Here, the second light conversion layer (122) and the third light conversion layer (132) may be light conversion layers (122, 132) that convert radiation of high energy (or the second energy), and in a form in which the second light conversion layer (122) is (relatively) thickened so as to be able to detect high energy radiation well, the thickness of the (thick) light conversion layer (122) that can detect high energy radiation well may be divided to form the second light conversion layer (122) and the third light conversion layer (132) on the first surface and the second surface of the second detection panel (121), respectively. In this case, since the third photoconversion layer (132) divides the thickness of the second photoconversion layer (122), a sufficient thickness (of the photoconversion layer) can be secured to detect high-energy radiation well by the second photoconversion layer (122) and the third photoconversion layer (132), while the distance from the surface far from the second detection panel (121) of each of the second photoconversion layer (122) and the third photoconversion layer (132) to the second detection panel (121) can be reduced (or minimized) (compared to the second photoconversion layer formed thick). Accordingly, the light-emitting position(s) in the second photoconversion layer (122) and the third photoconversion layer (132) can be brought closer to the second detection panel (121), thereby minimizing light loss and improving signal-to-noise ratio (SNR) and modulation transfer function (MTF) characteristics. At this time, the sum of the thicknesses of the second light conversion layer (122) and the third light conversion layer (132) may be greater than the thickness of the first light conversion layer (112).

[0126]

[0127] Figure 5 is a schematic cross-sectional view showing a radiographic apparatus according to another embodiment of the present invention.

[0128] Referring to FIG. 5, a radiographic apparatus according to another embodiment of the present invention will be examined in more detail. However, any details that overlap with those described above in relation to a radiation detector according to an embodiment of the present invention will be omitted.

[0129] A radiographic apparatus (200) according to another embodiment of the present invention may include a radiation detector (100) according to one embodiment of the present invention; a radiation source (210) that irradiates radiation (10) toward the radiation detector (100); and an image processing unit (220) that processes radiation of the first energy detected by the first radiation detection unit (110) and radiation of the second energy detected by the second radiation detection unit (120) to generate a radiation image.

[0130] The radiation detector (100) may be a radiation detector (100) according to one embodiment of the present invention, and the first radiation detection unit (110) may detect radiation of low energy (i.e., the first energy) and the second radiation detection unit (120) may detect radiation of high energy (i.e., the second energy). Through this, a dual-energy radiation image may be obtained.

[0131] Here, the radiation detector (100) may (further) include a housing (150) in which a first radiation detection unit (110) and a second radiation detection unit (120) are accommodated.

[0132] The housing (150) can accommodate a first radiation detection unit (110) and a second radiation detection unit (120), and a cover unit (150a) forming a radiation-transmitting surface on one side (e.g., a side facing a radiation source) can be provided (or equipped). The cover unit (150a) can be formed of a radiation-transmitting material, and a carbon material can be used. In addition, the housing (150) can include a back plate, a frame, and / or a side wall. For example, the housing (150) can be formed of a back plate, a frame, and / or a side wall as an integral part, and can be formed of an aluminum material.

[0133] A radiation source (210) can irradiate radiation (10) toward a radiation detector (100), and the radiation (10) irradiated toward the radiation detector (100) can generally penetrate a subject (20) and be incident on a radiation-transmitting surface of an exposed first radiation detection unit (110), and can be detected by the first radiation detection unit (110) and the second radiation detection unit (120). Among the incident radiation (10), radiation of the first energy can be detected by the first radiation detection unit (110), and radiation of the second energy can pass through the first radiation detection unit (110) and be detected by the second radiation detection unit (120). Here, the radiation source (210) can include a collimator that adjusts an irradiation area of ​​the radiation (10). The above collimator can be provided to the radiation source (210), and can control the irradiation area of ​​the radiation (10) and also control the irradiation direction of the radiation (10).

[0134] The image processing unit (220) can process the radiation of the first energy detected by the first radiation detection unit (110) and the radiation of the second energy detected by the second radiation detection unit (120) to generate a radiation image, and can register the two radiation images by subtracting and / or synthesizing the radiation image of the first energy (e.g., low energy) and the radiation image of the second energy (e.g., high energy). The image processing unit (220) can separate bones and soft tissues using the low-energy radiation image and the high-energy radiation image, and can improve image quality by synthesizing the radiation image of the first energy and the radiation image of the second energy.

[0135] Here, the first radiation detection unit (110) can detect radiation of the first energy, and the second radiation detection unit (120) can detect radiation of the second energy greater than the first energy. That is, since the first radiation detection unit (110) is located closer to the radiation source (210) than the second radiation detection unit (120), it can detect low-energy radiation (i.e., radiation of the first energy) to obtain a low-energy radiation image, and since the second radiation detection unit (120) is located farther from the radiation source (210) than the first radiation detection unit (110), it can detect high-energy radiation (i.e., radiation of the second energy greater than the first energy) to obtain a high-energy radiation image.

[0136]

[0137] In this way, in the present invention, by arranging the first radiation detection unit and the second radiation detection unit so that the second surface of the first detection panel and the second surface of the second detection panel face each other, the first detection panel and the second detection panel can have excellent thickness uniformity, so that the distance between the first photoconversion layer and the second photoconversion layer can be made generally constant, and accordingly, the image uniformity between the first energy radiation image generated through the first radiation detection unit and the second energy radiation image generated through the second radiation detection unit can be improved. At this time, a light-blocking layer can be provided between the first photoconversion layer and the second photoconversion layer to prevent light converted in the first photoconversion layer from affecting the second detection panel or light converted in the second photoconversion layer from affecting the first detection panel. And by forming at least one of the first detection panel and the second detection panel into a flexible panel and making it thin, the distance between the first photoconversion layer and the second photoconversion layer can be reduced, and accordingly, the reduction of radiation by the first detection panel and / or the second detection panel can be reduced, and parallax effects such as the difference in magnification between the radiation image of the first energy generated through the first radiation detection unit and the radiation image of the second energy generated through the second radiation detection unit can also be reduced.

[0138] FIG. 6 illustrates a mammography device according to one embodiment of the present disclosure.

[0139] Equipping a mammography device with the radiation detector described above can yield clearer images. Unlike other X-ray devices, mammography primarily photographs soft tissue. Furthermore, the breast, the target tissue for mammography, is sensitive, requiring low-radiation imaging compared to other devices. Furthermore, for early detection of lesions within breast tissue, images must be obtained with low noise, high contrast, and high resolution.

[0140] In this regard, conventionally, radiation sources were implemented simply as low-dose devices, and any deficiencies were compensated for through image processing. However, the mammography device of the present disclosure utilizes multiple detection panels, enabling imaging at even lower doses and obtaining higher-quality images.

[0141] In addition, when two radiation detectors are used as described above, since multiple images for X-rays of two energy regions are used, the amount of information in the image increases, so a higher quality X-ray image can be obtained. More specifically, the mammography device (600) of the present disclosure can obtain a composite image by synthesizing multiple radiation images based on two energies. In addition, the composite image obtained by the mammography device (600) of the present disclosure has a high resolution and noise can be greatly reduced in a specific material region. Hereinafter, the mammography device (600) of the present disclosure will be described in detail.

[0142] The mammography device (600) of the present disclosure may include a radiation source (620) and a radiation detector (610). The radiation source (620) may be configured to irradiate a patient's breast with radiation. The radiation detector (610) may be positioned facing the radiation source (620). The radiation detector (610) and the radiation source (620) may be coupled to a gantry (630). The gantry (630) may rotate with respect to a column (640). The gantry (630) may rotate to capture images of the breast from various angles. Even when the gantry (630) rotates, the detector (610) and the radiation source (620) may always face each other.

[0143] The radiation detector (610) can generate a first energy radiation image and a second energy radiation image based on the radiation that has passed through the patient's breast. The radiation detector (610) may further include the following components to obtain the first energy radiation image and the second energy radiation image. Since the components included in the radiation detector (610) have already been described, a redundant description will be omitted. The radiation detector (610) may include a first radiation detection unit (110) and a second radiation detection unit (120).

[0144] The first radiation detection unit (110) may include a first detection panel (111) having a first side and a second side that are parallel to each other, and a first photoconversion layer (112) provided on the first side of the first detection panel (111). The first radiation detection unit (110) may generate a radiation image of the first energy.

[0145] The second radiation detection unit (120) may include a second detection panel (121) having a first side and a second side that are parallel to each other, and a second photoconversion layer (122) provided on the first side of the second detection panel (121). The second radiation detection unit (120) may generate a radiation image of the second energy.

[0146] The first radiation detection unit (110) and the second radiation detection unit (120) can be arranged so that the second surface of the first detection panel (111) and the second surface of the second detection panel (121) face each other.

[0147] The first radiation detection unit (110) can detect radiation of a first energy from radiation incident on the first surface side of the first detection panel (111). In addition, the second radiation detection unit (120) can detect radiation of a second energy from radiation incident on the second surface side of the second detection panel (121) through the first radiation detection unit (110). The first energy and the second energy may be different. The first energy may be lower energy than the second energy. That is, the radiation image of the first energy may be a radiation image of relatively low energy compared to the radiation image of the second energy. The radiation image of the second energy may be a radiation image of relatively high energy compared to the radiation image of the first energy.

[0148] At least one of the first photoconversion layer (112) and the second photoconversion layer (122) may include a scintillator that converts radiation into visible light. For example, the first photoconversion layer (112) and the second photoconversion layer (122) may include cesium iodide (CsI). However, the present invention is not limited thereto, and the first photoconversion layer (112) and the second photoconversion layer (122) may include gadolinium oxysulfide (GOS).

[0149] According to various embodiments of the present disclosure, at least one of the first photoconversion layer (112) and the second photoconversion layer (122) may include a photoelectric material that generates an electrical signal by radiation. For example, the photoelectric material may include at least one of selenium (Se), such as amorphous selenium (α-Se), cadmium telluride (CdTe), such as crystalline cadmium telluride (crystalloid CdTe), or a crystalline cadmium telluride compound.

[0150] According to various embodiments of the present disclosure, among the first photoconversion layer (112) and the second photoconversion layer (122), the photoconversion layer onto which radiation is incident first may include a photoelectric material that generates an electrical signal by the radiation. Among the first photoconversion layer (112) and the second photoconversion layer (122), the photoconversion layer onto which radiation is incident later may include a scintillator material that converts radiation into visible light. For example, the first photoconversion layer (112) may include a photoelectric material, and the second photoconversion layer (122) may include a scintillator material. However, the present disclosure is not limited thereto.

[0151] More specifically, the first photoconversion layer (112) may be made of selenium (Se), and the second photoconversion layer may be made of gadolinium oxysulfide (GOS). In addition, the first photoconversion layer may be made of selenium (Se), and the second photoconversion layer may be made of cesium iodide (CsI).

[0152] Below, a process of obtaining a synthetic image based on a first energy radiation image and a second energy radiation image obtained using a first radiation detection unit (110) and a second radiation detection unit (120) is described.

[0153] A composite image is a method of decomposing a first energy radiographic image and a second energy radiographic image into components, comparing the first energy radiographic image and the second energy radiographic image for each component, and selectively synthesizing them in a direction that increases sharpness and contrast and reduces noise. Here, the component may refer to a predetermined target frequency range.

[0154] FIG. 7 is a drawing for explaining the operation of a mammography device according to one embodiment of the present disclosure.

[0155] The mammography device (600) may include a control unit for controlling the mammography device (600). The control unit may include an image processing unit (220). The control unit including the image processing unit (220) may perform a step (710) of obtaining a radiation image of a first energy using a first radiation detection unit (110). In addition, the control unit may obtain a step (720) of obtaining a radiation image of a second energy using a second radiation detection unit (120). The control unit may perform a step (730) of obtaining a composite image based on the radiation image of the first energy and the radiation image of the second energy.

[0156] Below, the process of obtaining a synthetic image is described in detail.

[0157] FIG. 8 is a drawing for explaining the operation of a mammography device according to one embodiment of the present disclosure.

[0158] The control unit may further perform the following steps to obtain a synthetic image.

[0159] The control unit may perform a step (810) of converting a radiation image of the first energy into a frequency domain to obtain a first frequency image. The control unit may obtain the first frequency image using a frequency transformation method such as a Fourier transform or a Laplace transform. The control unit may perform a step (820) of obtaining a first sub-frequency image for at least one target frequency range predetermined from the first frequency image. The number of first sub-frequency images may be the same as the number of target frequency ranges. One first sub-frequency image may be an image for one target frequency range. The target frequency range may be a predetermined frequency range. In this way, the control unit may divide the first frequency image by target frequency range and perform different image enhancement processing for each frequency. For example, since noise characteristics may differ by frequency range, the noise removal effect may be enhanced by removing noise by a different method by frequency range.

[0160] The control unit may perform a step (830) of converting a radiation image of the second energy into a frequency domain to obtain a second frequency image. The control unit may perform a step (840) of obtaining a second sub-frequency image for at least one target frequency range predetermined in the second frequency image. The method of obtaining the second sub-frequency image is the same as the method of obtaining the first sub-frequency image, so redundant description is omitted. The first sub-frequency image may correspond to the radiation image of the first energy, and the second sub-frequency image may correspond to the radiation image of the second energy. The first sub-frequency image and the second sub-frequency image may be images in the frequency domain.

[0161] The control unit can obtain a synthetic image based on the first sub-frequency image and the second sub-frequency image.

[0162] According to one embodiment of the present disclosure, the control unit can obtain a synthetic sub-frequency image by weighting pixels located at the same positions in the first sub-frequency image and the second sub-frequency image. The weighted average can be based on the following equation.

[0163] s_pixel = w * p1 + (1-w) *p2

[0164] Here, s_pixel is a value of a pixel included in the synthesized sub-frequency image, w is a weight that is greater than or equal to 0 and less than or equal to 1, p1 may be a value of a pixel included in the first sub-frequency image, and p2 may be a value of a pixel included in the second sub-frequency image. w may be a predetermined weight. In addition, the weight (w) may be different depending on the target frequency range. For example, a weight corresponding to the first target frequency range may be different from a weight corresponding to a second target frequency range that is different from the first target frequency range. The first sub-frequency image and the second sub-frequency image may be replaced with an improved first sub-frequency image and an improved second sub-frequency image.

[0165] The control unit can obtain a synthetic sub-frequency image for all frequency ranges. That is, the control unit can obtain at least one synthetic sub-frequency image. The control unit can obtain a synthetic image by converting the synthetic sub-frequency image into a spatial domain.

[0166] According to various embodiments of the present disclosure, the control unit can apply a predetermined image enhancement to at least one of the first sub-frequency image and the second sub-frequency image. The control unit can obtain an enhanced first sub-frequency image and an enhanced second sub-frequency image. The control unit can obtain at least one enhanced first sub-frequency image and at least one enhanced second sub-frequency image for all frequency ranges.

[0167] The control unit can obtain an improved first frequency image by merging at least one improved first sub-frequency image. The improved first frequency image can include the same frequency range as the first frequency image. The control unit can convert the improved first frequency image into a first spatial image. The control unit can obtain an improved second frequency image by merging at least one improved second sub-frequency image. The improved second frequency image can include the same frequency range as the second frequency image. The control unit can convert the improved second frequency image into a second spatial image. In the above, the control unit obtains the first spatial image and the second spatial image based on the improved first sub-frequency image and the improved second sub-frequency image, but the first spatial image and the second spatial image can also be obtained based on the first sub-frequency image and the second sub-frequency image. That is, the improved first sub-frequency image and the improved second sub-frequency image may not be used.

[0168] The control unit can obtain a composite image by weighting pixels at the same locations included in the first spatial image and the second spatial image. The weighted average can be based on the following equation.

[0169] ss_pixel = ws * ps1 + (1-ws) *ps2

[0170] Here, ss_pixel is a value of a pixel included in the synthetic image, ws is a weight that is greater than or equal to 0 and less than or equal to 1, ps1 may be a value of a pixel included in the first spatial image, and ps2 may be a value of a pixel included in the second spatial image. ws may be a predetermined weight. ws may be a fixed value, or may vary depending on at least one of the values ​​of ps1 and ps2. For example, the control unit may obtain ws based on a predetermined function that uses ps1 and ps2 as variables.

[0171] According to one embodiment of the present disclosure, the control unit may obtain a first corrected image by applying a first energy radiation image to an image enhancement model to obtain a synthetic image. The control unit may obtain a second corrected image by applying a second energy radiation image to the image enhancement model. The control unit may obtain a synthetic image based on the first corrected image and the second corrected image.

[0172] The image enhancement model may be a model for restoring a deteriorated image. The image generated by the mammography device (600) may be deteriorated due to light scattering caused by the physical characteristics of an indirect detector, x-ray scattering caused by a thick subject, etc. Therefore, the control unit may restore the deteriorated image using the image enhancement model for restoring the deteriorated image. The image enhancement model may be a predetermined function that uses a pixel value included in at least one of a first energy radiographic image and a second energy radiographic image as a variable. The control unit may obtain at least one of a first corrected image or a second corrected image based on the image enhancement model. In addition, the control unit may obtain a composite image based on the first corrected image and the second corrected image.

[0173] The control unit may apply an image enhancement model to a radiation image of a first energy to obtain a first sub-frequency image. More specifically, the control unit may apply the radiation image of the first energy to the image enhancement model to obtain a first corrected image. The image enhancement model may be processed in a spatial domain rather than a frequency domain. The control unit may perform a step (810) of converting the first corrected image into a frequency domain to obtain a first frequency image. The control unit may perform a step (820) of obtaining a first sub-frequency image for at least one target frequency range that is predetermined from the first frequency image.

[0174] However, it is not limited thereto, and the image enhancement model may be applied in the frequency domain. For example, the control unit may perform a step (810) of transforming a radiation image of the first energy into the frequency domain to obtain a first frequency image. The control unit may apply the image enhancement model to the first frequency image to obtain a first restored frequency image. The control unit may perform a step (820) of obtaining a first sub-frequency image for at least one target frequency range determined in advance from the first restored frequency image.

[0175] In addition, the control unit may apply an image enhancement model to the second energy radiation image to obtain a second sub-frequency image. More specifically, the control unit may apply the second energy radiation image to the image enhancement model to obtain a second corrected image. The image enhancement model may be processed in a spatial domain rather than a frequency domain. The control unit may perform a step (830) of converting the second corrected image into a frequency domain to obtain a second frequency image. The control unit may perform a step (840) of obtaining a first sub-frequency image for at least one target frequency range determined in advance from the first frequency image.

[0176] However, it is not limited thereto, and the image enhancement model may be applied in the frequency domain. For example, the control unit may perform a step (830) of transforming a radiation image of the second energy into the frequency domain to obtain a second frequency image. The control unit may apply the image enhancement model to the second frequency image to obtain a second restored frequency image. The control unit may perform a step (840) of obtaining a second sub-frequency image for at least one target frequency range that is predetermined from the second restored frequency image.

[0177] The control unit can obtain a synthetic image based on the first sub-frequency image and the second sub-frequency image. Since the process of obtaining the synthetic image has already been described, a redundant description will be omitted.

[0178] The image enhancement model can work as follows:

[0179] A method for processing a radiation image according to an image enhancement model of the present disclosure may include a step of obtaining a radiation image including at least one of a radiation image of a first energy or a radiation image of a second energy by using an indirect radiation detector including a photoconversion layer (112, 122) and a detection panel (111, 121). A method for processing a radiation image according to an image enhancement model may include a step of determining a value of a parameter defined in a point distribution function (PSF) according to the photoconversion layer (112, 122) or the detection panel (111, 121). In addition, a method for processing a radiation image according to an image enhancement model may include a step of deconvolving and correcting at least one of the radiation image of the first energy or the radiation image of the second energy by using a point distribution function (PSF) to which the value of the parameter is applied, thereby obtaining a corrected image including at least one of the first corrected image or the second corrected image.

[0180] When a radiation image including at least one of a first energy radiation image or a second energy radiation image is captured using an indirect radiation detector using a photoconversion layer (112, 122), light is scattered by the photoconversion layer (112, 122), causing a blurring phenomenon in the radiation image. At this time, the scattering of light by the photoconversion layer (112, 122) may have a Gaussian shape. In order to improve the sharpness of the radiation image by correcting the blurring phenomenon in the radiation image, in the present disclosure, a radiation image including a blurring phenomenon is defined as an image obtained by convolving a clear radiation image and a point distribution function (PSF), and the radiation image including the blurring phenomenon is corrected by deconvolving the radiation image using the point distribution function (PSF).

[0181] The image enhancement model can be applied to images acquired using an indirect radiation detector. That is, when a first energy radiation image is acquired using the direct method and a second energy radiation image is acquired using the indirect method, the control unit can apply the image enhancement model to the second energy radiation image. As previously explained, the indirect method can utilize a scintillator, and the direct method can utilize a photoelectric material.

[0182] The detection panel (111, 121) can store, for each pixel, the charge generated by visible light converted when radiation is irradiated to the photoconversion layer (112, 122). Here, the resolution of the radiation image can vary depending on the pixel size of the detection panel (111, 121).

[0183] And in parallel with the step of acquiring the radiation image, the value of the parameter defining the point distribution function (PSF) according to the photoconversion layer (112, 122) or the detection panel (111, 121) can be determined. The step of determining the value of the parameter may be performed simultaneously with the step of acquiring the radiation image, may be performed before the step of acquiring the radiation image, or may be performed after the step of acquiring the radiation image. The control unit may determine the value of the parameter defining the point distribution function (PSF) according to the photoconversion layer (112, 122) or the detection panel (111, 121). At this time, the control unit may determine the value of the parameter defining the point distribution function (PSF) according to the pixel size of the detection panel (111, 121), the thickness of the photoconversion layer (112, 122), and the type of scintillator included in the photoconversion layer.

[0184] In the step of determining the value of the above parameter, a corrected image obtained by deconvolving the radiographic image using a point distribution function (PSF) can be determined as a parameter value that satisfies the image quality standard. When the radiographic image is deconvolved and corrected, the sharpness of the corrected image is improved compared to the sharpness of the radiographic image. However, if the sharpness is improved too artificially, the inherent characteristics of the radiographic image are distorted. If the inherent characteristics of the radiographic image are distorted, the value as an image for medical diagnosis is lost. Therefore, by evaluating the image quality of the corrected image to determine whether the inherent characteristics of the radiographic image are distorted, the corrected image with the distorted inherent characteristics of the radiographic image can be filtered out. Therefore, if the value of the parameter is determined as a parameter value that satisfies the image quality standard, the radiographic image can be corrected into a corrected image with improved sharpness without distorting the inherent characteristics of the radiographic image.

[0185] The image quality can be evaluated by measuring at least one selected from the group consisting of a modulation transfer function (MTF), a detector quantum efficiency (DQE), a normalized noise power spectrum (NNPS), and a signal-to-noise ratio (SNR). The measurement values ​​of the modulation transfer function (MTF), the detector quantum efficiency (DQE), the normalized noise power spectrum (NNPS), and the signal-to-noise ratio (SNR) can be measured using an image evaluation tool, and the image quality can be evaluated by analyzing the characteristic graph of each measurement value. That is, it is possible to determine whether the unique characteristics of the radiological image are distorted through the characteristic graph of each measurement value.

[0186] The modulation transfer function (MTF) represents the frequency response of an imaging system, and can be defined as the ratio of image contrast to subject contrast, and is a measurement factor related to sharpness. In addition, the modulation transfer function (MTF) measures the spatial frequency of an image and is the ability to record the frequency of the area corresponding to each frequency, and it can be used to obtain resolution by indicating the degree to which an imaging system responds to spatial changes in the image, and is widely used to evaluate the sharpness of an image, and can be used to determine whether sharpness has been improved through the modulation transfer function (MTF).

[0187] Quantum detection efficiency (DQE) is a measure of the signal-to-noise ratio (SNR) transmission characteristics, a parameter that expresses the amount of noise introduced by the final image. In other words, it measures the overall SNR performance of a radiation detector, its ability to transmit the SNR. DQE can be defined as the square of the ratio of the output signal-to-noise ratio (SNR) to the input signal-to-noise ratio (SNR).

[0188] In addition, quantum detection efficiency (DQE) is a comprehensive index representing the quality of a radiographic image, and is obtained by the modulation transfer function (MTF), normalized noise power spectrum (NNPS), and signal-to-noise ratio (SNR). Therefore, it can comprehensively evaluate image quality including the modulation transfer function (MTF), normalized noise power spectrum (NNPS), and signal-to-noise ratio (SNR), and can effectively determine whether the inherent characteristics of the image are distorted.

[0189] The noise power spectrum (NPS) is a spatial frequency representation of the distribution of noise variance. It indicates the dependence of noise, which is a factor of pixel-to-pixel variation in an image, on spatial frequency and is a noise-related measurement factor. The normalized noise power spectrum (NNPS) refers to the normalized noise power spectrum (NPS), which can be obtained by averaging all spectral samples.

[0190] Image noise refers to uncertainty or inaccuracy in an image signal, and can be broadly divided into noise caused by the number of photons that constitute the image information and noise caused by the image signal processing circuit. The former has a higher degree of uncertainty when the number of photons that constitute the image information is small, and on the other hand, as the number of photons increases, the probability of being detected as an image signal increases, which can reduce the influence of noise on the image signal. In order to evaluate the signal-to-noise ratio of a radiological imaging system, an image can be acquired using a lead phantom with the central portion removed, and the gray-scale value of the acquired image measured along a guide line can be utilized. The image signal refers to the difference (delta_D) in the gray scale value between the surrounding lead phantom and the central circular area, and the image noise refers to the standard deviation (s) of the gray scale value of the acquired image. The ratio of these (delta_D / s) can be defined as the signal-to-noise ratio (SNR), which is a measurement factor related to the signal (Signal) and noise (Noise).

[0191] The control unit can obtain a corrected image by deconvolving the radiographic image using the point distribution function (PSF) to which the value of the parameter is applied. The radiographic image is deconvolved and corrected using the point distribution function (PSF) to which the value of the parameter is applied. If only the value of the parameter is known, the radiographic image can be corrected by deconvolving the radiographic image and the point distribution function (PSF). The deconvolution process assumes that an image including a blur phenomenon is generated by convolution of the point distribution function (PSF) and a clear image, and can repeatedly perform the algorithm until the residual error value between the blurry image obtained from the shooting (i.e., including light scattering by the scintillator) and the blurry image estimated by the user is sufficiently small. In addition, the deconvolution can use spatial-invariant deconvolution that restores the entire image using a single point distribution function (PSF). Meanwhile, spatial-variant deconvolution can be used to restore the image using multiple individual point distribution functions (PSFs) according to the location within the radiographic image. Spatial-variant deconvolution using individual PSFs for each location can have higher sharpness than spatial-invariant deconvolution, but the process of obtaining individual PSFs for each location is complicated, so spatial-invariant deconvolution can be mainly used.

[0192] Indirect radiation detectors have higher Detective Quantum Efficiency (DQE) than direct radiation detectors, but lower sharpness (or MTF) than direct radiation detectors. Here, the quantum detection efficiency (DQE) is the radiation conversion efficiency, and a higher quantum detection efficiency (DQE) means that a good image can be obtained even with a lower radiation dose. Therefore, in the present disclosure, when using an indirect radiation detector, scintillator scatter caused by the structural characteristics of the hardware is corrected using a software algorithm, so that high sharpness comparable to that of a direct radiation detector can be obtained while maintaining the high quantum detection efficiency (DQE) of the indirect radiation detector.

[0193] As a result of performing the image enhancement model according to the present disclosure, it was possible to obtain images with high sharpness and higher quantum detection efficiency (DQE) than direct-mode radiation detectors. In this case, there is an effect of obtaining clearer and higher-quality images with a lower radiation dose. In other words, when a product with a high quantum detection efficiency (DQE) is used, a lower radiation dose is required, which lowers the patient's radiation exposure, and when the sharpness is high, a clearer image can be obtained, which is useful for diagnosis.

[0194] The control unit can use a mathematical noise model to reduce noise in a synthetic image. In general, it is difficult to effectively remove only noise components from an image, and excessive noise filters run the risk of blurring the image. An AI noise model based on the noise characteristics of an X-ray image and information from two images (a first energy radiographic image or a second energy radiographic image) obtained from the detector of the present disclosure can distinguish noise components more accurately with more information than a single-energy image, thereby enabling stable noise component removal.

[0195] The control unit can obtain noise information by applying at least one of the first energy radiographic image or the second energy radiographic image to a noise model. Based on the noise information, the control unit can obtain an improved synthetic image by removing noise from the synthetic image.

[0196] The noise model may be a model that extracts noise information based on at least one of a first energy radiographic image or a second energy radiographic image. The noise model may be a rule-based model or a machine learning model. The noise model may be a model that machine-learns the relationship between noise information for the first energy radiographic image or the second energy radiographic image.

[0197] According to various embodiments of the present disclosure, the control unit may obtain noise information by applying at least one of the first sub-frequency image or the second sub-frequency image to a noise model. The control unit may obtain at least one of the improved first sub-frequency image or the improved second sub-frequency image by removing noise information obtained from at least one of the first sub-frequency image or the second sub-frequency image, and may obtain a synthetic image based on the improved first sub-frequency image or the improved second sub-frequency image. Since the process of obtaining the synthetic image based on the first sub-frequency image or the second sub-frequency image has already been described, a redundant description will be omitted.

[0198] A mammography device (600) using the method of acquiring a synthetic image of the present disclosure can acquire images at a level equivalent to that of high-dose images even at low doses. Since images of different X-ray energies of the same object are acquired, the contrast is improved compared to single-energy images, and the influence of artifacts can be minimized by using a mathematical model based on physical laws.

[0199] While preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described embodiments, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible without departing from the spirit and scope of the present invention as claimed in the claims. Accordingly, the technical protection scope of the present invention should be defined by the following claims.

Claims

1. Mammography device, A radiation source that irradiates the patient's breast; and A radiation detector is disposed opposite the radiation source and generates a first energy radiation image and a second energy radiation image based on radiation that has penetrated and reached the patient's breast, The above radiation detector, A first radiation detection unit comprising a first detection panel having first and second surfaces that are parallel to each other, and a first photoconversion layer provided on the first surface of the first detection panel, and generating a radiation image of the first energy; and A second detection panel having first and second surfaces that are parallel to each other, and a second photoconversion layer provided on the first surface of the second detection panel, and a second radiation detection unit that generates a radiation image of the second energy; A mammography device in which the first radiation detection unit and the second radiation detection unit are arranged so that the second surface of the first detection panel and the second surface of the second detection panel face each other.

2. In paragraph 1, The first radiation detection unit detects radiation of a first energy from radiation incident on the first surface of the first detection panel, The second radiation detection unit detects radiation of a second energy from radiation incident on the second surface side of the second detection panel through the first radiation detection unit, The first energy and the second energy are different mammography devices.

3. In paragraph 1, A mammography device, wherein at least one of the first photoconversion layer and the second photoconversion layer includes a scintillator that converts radiation into visible light.

4. In paragraph 3, A mammography device wherein the first photoconversion layer and the second photoconversion layer are made of cesium iodide (CsI).

5. In paragraph 3, A mammography device wherein the first photoconversion layer and the second photoconversion layer are made of gadolinium oxysulfide (GOS).

6. In paragraph 1, A mammography device, wherein at least one of the first photoconversion layer and the second photoconversion layer includes a photoelectric material that generates an electrical signal by radiation.

7. In paragraph 1, Among the first photoconversion layer and the second photoconversion layer, the photoconversion layer onto which radiation is first incident includes a photoelectric material that generates an electric signal by the radiation, A mammography device, wherein the photoconversion layer on which the radiation is incident later among the first photoconversion layer and the second photoconversion layer includes a scintillation material that converts the radiation into visible light.

8. In paragraph 7, The above first photoconversion layer is made of selenium (Se), A mammography device wherein the second photoconversion layer is made of gadolinium oxysulfide (GOS).

9. In paragraph 7, The above first photoconversion layer is made of selenium (Se), A mammography device wherein the second photoconversion layer is made of cesium iodide (CsI).

10. In paragraph 1, A control unit for controlling the mammography device is included, The above control unit obtains a radiation image of the first energy using the first radiation detection unit, The above control unit obtains a radiation image of the second energy using the second radiation detection unit, A mammography device that obtains a composite image based on a radiographic image of the first energy and a radiographic image of the second energy.

11. In paragraph 10, The above control unit, In order to obtain the above synthetic image, the first energy radiation image is applied to the image enhancement model to obtain the first corrected image, Applying the second energy radiation image to the image improvement model to obtain a second corrected image, A mammography device that obtains a synthetic image based on the first corrected image and the second corrected image.

12. In paragraph 10, The above control unit, Obtaining noise information by applying at least one of the first energy radiographic image or the second energy radiographic image to a noise model, A mammography device that obtains an improved synthetic image by removing noise from the synthetic image based on the above noise information.

13. In paragraph 10, A mammography device wherein the first energy radiation image is a lower energy radiation image than the second energy radiation image.

Images