Radiation imaging method using multiple energy scout views - Patents.com

Abstract

The invention relates to a radiation imaging method comprising at least one operating mode, in which frontal multi-energy scout views and lateral multi-energy scout views are created (1) by performing a preliminary vertical scan of a patient standing along said vertical scan direction by frontal and lateral radiation sources (101, 103) and frontal and lateral radiation detectors (102, 104), such that the frontal and lateral radiation detectors (102, 104) generate at least a first frontal scout view corresponding to a low-energy frontal scout view and a second frontal scout view corresponding to a high-energy frontal scout view. a second frontal scout view corresponding to a high-energy frontal scout view, a first lateral scout view corresponding to a low-energy lateral scout view, and a second lateral scout view corresponding to a high-energy lateral scout view, and the first frontal scout view and the first lateral scout view and the second frontal scout view and the second lateral scout view are combined and processed (20) to assess at least a thickness (22) of the patient's bones, at least a thickness (22) of the patient's soft tissues, and a localization (21) of specific bones of the patient at different imaging positions along the vertical scanning direction.

Description

[Technical field]

[0001] The present invention relates to the technical field of radiographic imaging methods and radiological devices for carrying out said radiological methods. [Background technology]

[0002] Various types of radiological images can be produced, including: A radiological scan image directed at a full (detailed and complete) view of a patient, or of a patient's organ, or of a part of a patient's organ, used for diagnosis by a specialist; There are radiological scan images directed at the bone density distribution in, of, or of a patient's tissue, or of a portion of a patient's tissue, that are used for expert bone density assessment.

[0003] The radiological image is preferably an X-ray image.

[0004] To improve the accuracy of diagnosis and / or bone density assessment, in a first step a scout view is performed, then using information extracted from this scout view to adapt the imaging parameters a scan image is performed, which is used by the specialist for either diagnosis or bone density assessment.

[0005] The scout view and scan images are performed by vertically scanning a frontal imaging line including a frontal radiation source and a frontal radiation detector, and / or a lateral imaging line including a lateral radiation source and a lateral radiation detector, along the height of a standing patient.

[0006] According to the first prior art, when performing a mono-energy scout view following a mono-energy scan image, the imaging parameters are adapted to allow obtaining a diagnostic image with good quality, but the imaging parameters cannot give a good result of bone density evaluation, i.e. a good result of bone density evaluation cannot be derived from the diagnostic image. If a bone density evaluation is then also required, not only does a new scan image with different imaging parameters have to be made, but the new scan image may not correspond exactly topologically to the previous scan image, since the standing patient has moved at least a little in the meantime.

[0007] According to the second prior art, when performing a multi-energy scan image, the imaging parameters are adapted to allow obtaining a good quality bone density image, but this imaging parameter cannot give a good result of diagnosis, i.e. a good result of a diagnostic image cannot be derived from this bone density image. Then, if a diagnosis is also required, not only a new scan image with different imaging parameters needs to be made, but this new scan image may not correspond exactly topologically to the previous scan image, since the standing patient has moved at least a little in the meantime. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] EP16711889 [Patent Document 2] U.S. Patent Application No. 1607660 [Patent Document 3] EP17758269 [Patent Document 4] U.S. Patent Application No. 16628410 [Patent Document 5] WO2021 / 094806 [Patent Document 6] WO2021 / 094404 Summary of the Invention [Means for solving the problem]

[0009] The object of the present invention is to at least partially alleviate the above mentioned drawbacks.

[0010] More specifically, the present invention aims to provide scan images which can be used for diagnosis with good results, but also In order to give correct results for bone density assessment as well, at the cost and lower radiation dose of simple multi-energy views (scout views are performed with about 10 times or less radiation dose compared to scan images), partial scout views can be extracted and further combined from the multi-energy scout views. The combination of both partial scout views leads to an accurate assessment of bone density. Thus, in a single overall operation and in a fairly simple manner, both a good diagnosis and an accurate bone density assessment can be derived from a scan image and its scout views. Or, at the same time, to provide a scan image from which partial images can be extracted and further combined in order to give good results for bone density assessment as well. The combination of both partial images leads to a correct assessment of bone density. Thus, both a good diagnosis and a good bone density assessment can be derived from the same scan image. Moreover, since the diagnosis and the good bone density assessment can be derived from the same image, there is an exact topological correspondence between the diagnosis and the good bone density assessment, since the standing patient is in exactly the same position for both.

[0011] Therefore, to be of good quality and useful for both diagnosis and bone density assessment, radiological methods must: First, a multi-energy scout view, which in the prior art is only a single energy scout view; Second, extracted information from this multi-energy scout view, which is used to perform an improved scan image, whether a single-energy scan image or a multi-energy scan image, which is only single-energy in the prior art, and Use.

[0012] A multi-energy scout view gives even better results if performed before a multi-energy scan image, rather than before a single-energy scan image.

[0013] The multi-energy scout view can be either a frontal scout view or a side scout view, or can include both a frontal scout view and a side scout view.

[0014] A first object of the present invention deals with en face single energy or multi-energy scan images performed after an en face multi-energy scout view.

[0015] This first objective is to two radiation sources having mutually orthogonal imaging directions, one front radiation source and one side radiation source, sliding vertically to perform a vertical scan of a patient standing along a vertical scanning direction; two radiation detectors, one frontal radiation detector and one side radiation detector, respectively associated with the two radiation sources, sliding vertically to perform a vertical scan of a patient standing along the vertical scan direction, at least one of the frontal radiation detectors being a multi-energy counting detector; This is achieved by a radiation imaging method comprising: The radiological method includes at least one mode of operation, the at least one mode of operation comprising: A frontal multi-energy scout view is created by performing a preliminary vertical scan of a patient standing along the vertical scan direction with the frontal radiation source and the frontal radiation detector, such that the frontal radiation detector detects at least: a first frontal scout view, referred to as a low-energy frontal scout view, received by the frontal radiation detector and corresponding to a first portion of energy below a first given energy threshold; a second frontal scout view, referred to as a high energy frontal scout view, corresponding to a second portion of the energy received by the frontal radiation detector that is above a second given energy threshold; Given The first frontal scout view and the second frontal scout view At least the patient's bone thickness and At least the thickness of the patient's soft tissue; Localizing specific bones of the patient at different imaging positions along the vertical scan direction; are combined and processed to evaluate a frontal image is produced by performing a vertical scan of a standing patient along the vertical scan direction with the frontal radiation source and the frontal radiation detector; a modulation of a drive current intensity of at least the frontal radiation source along the vertical scan direction is dependent on a thickness of the patient's bones, a thickness of the patient's soft tissues, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; Preferably, the modulation of the driving voltage intensity of the frontal radiation source along the vertical scan direction depends on a bone thickness of the patient, a thickness of the soft tissue of the patient, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; The driving current intensity of the front radiation source is automatically performed without voltage intensity modulation of the front radiation source; a total radiation dose received by a patient during said vertical scan; for the en face image, local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; or, Both the driving current intensity and the driving voltage intensity of the front radiation source are automatically adjusted simultaneously, preferably synchronously; a total radiation dose received by a patient during said vertical scan; for the en face image, local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; Try to improve the compromise between

[0016] A second object of the present invention deals with lateral single energy scan images or lateral multi-energy scan images performed after a lateral multi-energy scout view.

[0017] This second objective is to two radiation sources having mutually orthogonal imaging directions, one front radiation source and one side radiation source, sliding vertically to perform a vertical scan of a patient standing along a vertical scanning direction; two radiation detectors, one front radiation detector and one side radiation detector, respectively associated with the two radiation sources, sliding vertically to perform a vertical scan of a patient standing along the vertical scan direction, at least one of the side radiation detectors being a multi-energy counting detector; This is achieved by a radiation imaging method comprising: The radiological method includes at least one mode of operation, the at least one mode of operation comprising: A lateral multi-energy scout view is created by performing a preliminary vertical scan of a patient standing along the vertical scan direction with the lateral radiation source and the lateral radiation detector, such that the lateral radiation detector detects at least: a first side scout view, referred to as a low energy side scout view, received by the side radiation detector and corresponding to a first portion of energy below a first given energy threshold; a second side scout view, referred to as a high energy side scout view, corresponding to a second portion of the energy received by the side radiation detector that is above a second given energy threshold; Given The first side scout view and the second side scout view At least the patient's bone thickness and At least the thickness of the patient's soft tissue; Localizing specific bones of the patient at different imaging positions along the vertical scan direction; are combined and processed to evaluate a lateral image is produced by performing a vertical scan of a standing patient along the vertical scan direction with the lateral radiation source and the lateral radiation detector; a modulation of a drive current intensity of at least the side radiation source along the vertical scan direction is dependent on a thickness of the patient's bone, a thickness of the patient's soft tissue, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; Preferably, the modulation of the driving voltage intensity of the side radiation source along the vertical scan direction depends on a thickness of the patient's bone, a thickness of the patient's soft tissue, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; The driving current intensity modulation of the side radiation source is automatically performed without voltage intensity modulation of the side radiation source; a total radiation dose received by a patient during said vertical scan; For lateral images, local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; or, Both the driving current intensity modulation and the driving voltage intensity modulation of the side radiation source are performed automatically, simultaneously, preferably synchronously; a total radiation dose received by a patient during said vertical scan; For lateral images, local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; Try to improve the compromise between

[0018] A third object of the present invention deals with both frontal and side scan images, either mono- or multi-energy, performed after both frontal and lateral multi-energy scout views.

[0019] This third objective is to two radiation sources having mutually orthogonal imaging directions, one front radiation source and one side radiation source, sliding vertically to perform a vertical scan of a patient standing along a vertical scanning direction; two radiation detectors, one front radiation detector and one side radiation detector, respectively associated with the two radiation sources, sliding vertically to perform a vertical scan of a patient standing along the vertical scan direction, the two radiation detectors being two multi-energy counting detectors respectively; This is achieved by a radiation imaging method comprising: The radiological method includes at least one mode of operation, the at least one mode of operation comprising: A frontal multi-energy scout view and a lateral multi-energy scout view are generated by performing a preliminary vertical scan of a patient standing along the vertical scan direction with the frontal and lateral radiation sources and the frontal and lateral radiation detectors, such that the frontal and lateral radiation detectors detect at least: a first frontal scout view, referred to as a low-energy frontal scout view, received by the frontal radiation detector and corresponding to a first portion of energy below a first given energy threshold; a second frontal scout view, referred to as a high energy frontal scout view, corresponding to a second portion of the energy received by the frontal radiation detector that is above a second given energy threshold; a first side scout view, referred to as a low energy side scout view, received by the side radiation detector and corresponding to a first portion of energy below a first given energy threshold; a second side scout view, referred to as a high energy side scout view, corresponding to a second portion of the energy received by the side radiation detector that is above a second given energy threshold; Given the first front scout view and the first side scout view and the second front scout view and the second side scout view; At least the patient's bone thickness and At least the thickness of the patient's soft tissue; Localizing specific bones of the patient at different imaging positions along the vertical scan direction; are combined and processed to evaluate a frontal image is produced by performing a vertical scan of a patient standing along the vertical scan direction with the frontal radiation source and the frontal radiation detector, and a lateral image is produced by performing a vertical scan of a patient standing along the vertical scan direction with the lateral radiation source and the lateral radiation detector, both the frontal image and the lateral image being produced during the same vertical scan; a modulation of drive current intensity of both the front radiation source and the side radiation source along the vertical scan direction is dependent on a thickness of the patient's bone, a thickness of the patient's soft tissue, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; Preferably, the modulation of the driving voltage intensity of both the front radiation source and the side radiation source along the vertical scan direction is dependent on a thickness of the patient's bone, a thickness of the patient's soft tissue, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; a total radiation dose received by a patient during said vertical scan; The driving current intensity modulation of the front radiation source is automatically performed simultaneously, preferably synchronously, without voltage intensity modulation of the front radiation source, and the driving current intensity modulation of the side radiation source is automatically performed simultaneously, preferably synchronously, without voltage intensity modulation of the side radiation source, and for the frontal image and the lateral image, local image contrasts of the identified specific bone localizations at different imaging positions along the vertical scanning direction. or, Both the driving current intensity modulation and the driving voltage intensity modulation of the front radiation source are automatically performed simultaneously, preferably synchronously, and both the driving current intensity modulation and the driving voltage intensity modulation of the side radiation source are automatically performed simultaneously, preferably synchronously, and a total radiation dose received by a patient during said vertical scan; and for the frontal image and the lateral image, local image contrasts of the identified specific bone localizations at different imaging positions along the vertical scanning direction. Try to improve the compromise between

[0020] Preferred embodiments include one or more of the following features which can be taken separately or together, in partial or complete combination with any of the aforementioned objects of the invention.

[0021] Preferably, The frontal multi-energy scout view is created by performing a single preliminary vertical scan of a patient standing along the vertical scan direction with the frontal radiation source and the frontal radiation detector, such that the frontal radiation detector detects at least: the first frontal scout view; the second frontal scout view; Given The lateral multi-energy scout view is created by performing a single preliminary vertical scan of a patient standing along the vertical scan direction with the lateral radiation source and the lateral radiation detector, such that the lateral radiation detector detects at least: the first side scout view; said second side scout view; Given Both the frontal multi-energy scout view and the lateral multi-energy scout view are made during the same single preliminary vertical scan.

[0022] Thus, because the frontal and lateral scout views are both performed simultaneously during the same single vertical scan, and the standing patient does not move between them, the frontal and lateral scout views correspond exactly to one another topologically.

[0023] Preferably, the frontal image is produced by performing a single vertical scan of a patient standing along the vertical scan direction with the frontal radiation source and the frontal radiation detector; the lateral image is produced by performing a single vertical scan of a patient standing along the vertical scan direction with the lateral radiation source and the lateral radiation detector; Both the front and side images are produced during the same single vertical scan.

[0024] Thus, since the frontal and lateral images are both performed simultaneously during the same vertical scan, and the standing patient does not move in between, the frontal and lateral images correspond exactly to each other topologically.

[0025] Preferably, said first given energy threshold is less than or equal to said second given energy threshold, and preferably equal to said second given energy threshold.

[0026] Thus, in both cases the full range of energy thresholds is covered, with the second case being less costly.

[0027] Preferably, the first given energy threshold is equal to the second given energy threshold; The frontal multi-energy scout view and / or the side multi-energy scout view may be obtained by detecting a frontal radiation detector and / or a side radiation detector, 1. The first frontal scout view, a third frontal scout view, called a full-energy frontal scout view, corresponding to the total energy received by the frontal radiation detector; First, give the second frontal scout view is obtained by subtracting the first frontal scout view from the third frontal scout view; and / or the first side scout view; and / or a third side scout view, called a full energy side scout view, corresponding to the total energy received by the side radiation detector. First, give The second side scout view is obtained by subtracting the first side scout view from the third side scout view. It is created as follows.

[0028] Thus, the full-energy scout view and the high-energy scout view can be directly provided by the detector, and the low-energy scout view can be obtained by simple subtraction by subtracting the high-energy scout view from the full-energy scout view.

[0029] Preferably, the first front and / or lateral scout view and the second front and / or lateral scout view are combined and processed to assess a thickness profile of the patient's bone along the vertical scanning direction; and / or the first frontal and / or lateral scout view and the second frontal and / or lateral scout view are combined and processed to assess a thickness profile of the patient's soft tissue along the vertical scanning direction; the frontal image is produced by performing a vertical scan of a standing patient along the vertical scan direction with the frontal radiation source and the frontal radiation detector; a modulation of a drive current intensity of at least the frontal radiation source along the vertical scanning direction is dependent on a bone thickness profile of the patient and / or a soft tissue thickness profile of the patient along the vertical scanning direction; Preferably, said modulation of a driving voltage intensity of said frontal radiation source along said vertical scanning direction also depends on a bone thickness profile of said patient and on a soft tissue thickness profile of said patient along said vertical scanning direction; the lateral image is produced by performing a vertical scan of a patient standing along the vertical scan direction with the lateral radiation source and the lateral radiation detector; a modulation of a drive current intensity of at least the side radiation source along the vertical scanning direction is dependent on a bone thickness profile of the patient and / or a soft tissue thickness profile of the patient along the vertical scanning direction; Preferably, said modulation of a driving voltage intensity of said side radiation source along said vertical scanning direction also depends on a bone thickness profile of said patient and a soft tissue thickness profile of said patient along said vertical scanning direction; Both the front and side images are produced during the same vertical scan.

[0030] Thus, since the frontal and lateral images are both performed simultaneously during the same vertical scan, and the standing patient does not move in between, the frontal and lateral images correspond exactly to each other topologically.

[0031] Preferably, the driving current intensity modulation of the front radiation source and / or the side radiation source is performed automatically without voltage intensity modulation of the front radiation source and / or the side radiation source; reducing the overall radiation dose received by a patient during said vertical scan; For the frontal image and / or the lateral image, for all or a part of the thickness of the patient along the vertical scanning direction, the local image contrast of the identified specific bone localization at different imaging positions along the same vertical scanning direction is not reduced below a given contrast threshold. Try to improve the compromise between or both the driving current intensity modulation and the driving voltage intensity modulation of the front radiation source and / or the side radiation source are performed automatically, simultaneously, preferably synchronously; reducing the overall radiation dose received by a patient during said vertical scan; increasing a local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction for the frontal image and / or the lateral image, for all or a part of a patient thickness along the vertical scan direction, with the same total radiation dose, but without drive current intensity modulation or drive voltage intensity modulation; To improve the compromise between

[0032] This means that It is possible to aim for the lowest possible overall radiation dose while maintaining the correct prescribed image quality; or improving image quality without unduly increasing overall radiation dose; or even further, that the margin provided by the present invention can be distributed in part to reduce radiation dose and in part to maintain a given image quality. means...

[0033] Preferably, the driving current intensity modulation of the front radiation source and / or the side radiation source is performed automatically without voltage intensity modulation of the front radiation source and / or the side radiation source; reducing the overall radiation dose received by a patient during said vertical scan; Improving a contrast-to-noise ratio or a ratio between the contrast-to-noise ratio and the square root of the total radiation dose of the identified specific bone localization at different imaging positions along the vertical scan direction for local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction for the lateral image and / or the frontal image, for all or part of the patient thickness along the vertical scan direction, with the same total radiation dose but without drive current intensity modulation. Try to improve the compromise between or both the driving current intensity modulation and the driving voltage intensity modulation of the front radiation source and / or the side radiation source are performed automatically, simultaneously, preferably synchronously; reducing the overall radiation dose received by a patient during said vertical scan; Improving the contrast-to-noise ratio or the ratio between the contrast-to-noise ratio and the square root of the total radiation dose of the identified specific bone localization at different imaging positions along the vertical scan direction for the frontal image and / or the lateral image, for all or part of the patient thickness along the vertical scan direction, with the same total radiation dose but without drive current intensity modulation or drive voltage intensity modulation, for local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; To improve the compromise between

[0034] This means that It is possible to aim for the lowest possible overall radiation dose whilst maintaining a given good image quality; or that it is possible to significantly improve image quality without increasing the overall radiation dose; or even further, that the margin provided by the present invention can be distributed in part to reduce radiation dose and in part to maintain a given better image quality. means.

[0035] Preferably, The frontal multi-energy scout view acquisition may include at least two energy bins, or at least three energy bins, or at least six energy bins. and / or at most 20 energy bins, or at most 15 energy bins, or at most 10 energy bins This is carried out using and / or the side multi-energy scout view acquisition includes at least two energy bins, or at least three energy bins, or at least six energy bins. and / or at most 20 energy bins, or at most 15 energy bins, or at most 10 energy bins This is performed using

[0036] Thus, a larger number of bins allows different tissue textures within a patient to be more accurately distinguished from one another, but at the expense of increased system complexity and the risk of less signal being available in each bin.

[0037] Preferably, the first and second frontal scout views are processed into a multi-material decomposition having at least two material thickness vertical profiles; Preferably, bimaterial decomposition between AI and PMMA or HA (hydroxyapatite) and H 2 It is processed into one of two materials decomposed between o, and / or the first and second side scout views are processed into a multi-material decomposition having at least two material thickness normal vectors; Preferably, a bimaterial decomposition between AI and PMMA, or HA and H 2O is processed into one of two materials decomposed.

[0038] Indeed, on the one hand, AI or HA show X-ray attenuation properties close to those of human bone, and on the other hand, PMMA or H 2 O exhibits X-ray attenuation characteristics similar to those of human soft tissue.

[0039] Preferably, For each said radiation detector, the pixel size of the radiation detector is in the range of 50 μm to 250 μm, alternatively in the range of 80 μm to 150 μm, alternatively about 100 μm; and / or the overall height of the radiation detector is in the range of 0.1 cm to 1.2 cm, or in the range of 0.2 cm to 1.0 cm, or in the range of 0.3 cm to 0.7 cm; and / or the overall width of the radiation detector is in the range of 10 cm to 80 cm, or in the range of 20 cm to 70 cm, or in the range of 30 cm to 60 cm; And / or the radiation detector may be operated in a time delay and sum mode.

[0040] Thus, the image resolution is improved without creating too many artifacts and the entire effective width of the patient can be covered.

[0041] Preferably, said identified specific bone localization comprises the patient's spine, preferably is the patient's spine.

[0042] Indeed, the patient's spine is the particular bony localization that is the most interesting to analyze in detail within the patient's body for orthopedic imaging purposes and is therefore used to drive the current intensity modulation.

[0043] Alternatively, the specific bone localization could be the pelvis, arms, or legs of a standing patient along a vertical scan direction, depending on the region of interest within the portion of the patient's body that is imaged.

[0044] Preferably, both the drive current intensity modulation and the drive voltage intensity modulation of the front radiation source and / or the side radiation source are also performed to reach a signal-to-noise ratio value for the front image and / or the side image that is constant and common to a majority of the imaging positions along the vertical scanning direction, preferably to all the imaging positions along the vertical scanning direction, but which can take two different values ​​for the front image and the side image, respectively.

[0045] Preferably, for each of said frontal and / or lateral images, said signal to noise ratio value is constant and pre-determined for each different patient organ being imaged.

[0046] Preferably, For a frontal image of the patient's spine, said standard signal-to-noise ratio value corresponds to a number of X-ray photons received per detector pixel comprised between 50 and 70, the operator of the radiological imaging method preferably having the possibility to deviate, via a manual command, by at least -25% or +100%, more preferably by at least -50% or +200%, And / or for lateral images of the patient's spine, said standard signal-to-noise ratio value corresponds to a number of X-ray photons received per detector pixel comprised between 20 and 40, the operator of the radiographic imaging method preferably having the possibility to deviate by at least -25% or +100%, more preferably by at least -50% or +200%, via a manual command.

[0047] Therefore, with a constant optimized signal-to-noise ratio along or along the entire vertical scan direction, the local image contrast of identified specific bones at different imaging positions along the vertical scan direction is significantly improved, especially for those that were actual regions of interest in the frontal and / or lateral images.

[0048] Preferably, the front and / or lateral images, after having undergone at least the local image contrast improvement, are normalized by homogenization of the raw radiation to remove image artifacts arising from the drive current intensity modulation and the drive voltage intensity modulation, and preferably, the front and / or lateral images, after having been normalized, are subjected to a contrast enhancement step.

[0049] In fact, due to this drive modulation, some artifacts were present in the frontal and / or lateral images, which overlapped with some modulation patterns of light and dark grey levels on the images, making the interpretation of these images a little difficult for the operator or an expert in radiological imaging methods.

[0050] Preferably, the localization of said identified specific bones excludes, if any, metallic prostheses, e.g. of parts of the skeleton of the patient's body, or metallic parts, e.g. metallic protective gear, which have been worn on the patient's body prior to performing said radiographic imaging method.

[0051] Indeed, these (for the patient) foreign bodies introduced in or on the patient's body may lead to a bad optimization of the emitted dose, since they are metallic and therefore stop much more radiation (X-rays) than the rest of the patient's body, with the risk of leading to an overexposure to the emitted radiation at the heights corresponding to these foreign bodies. If the driving voltage strength is constant, and the metallic outliers are not excluded, more or all parameters will be selected for the maximum thickness, leading to the emission of a higher or much higher radiation dose than required, which may lead to a worse outcome, since it would be harmful for the patient.

[0052] Preferably, The modulation of both the current and voltage intensity is For larger patient thicknesses, both the current intensity and the voltage intensity are increased simultaneously; For smaller patient thicknesses, both the current intensity and the voltage intensity are simultaneously reduced; The rate of change of the current intensity is slower than the rate of change of the voltage intensity.

[0053] Thus, every part of the patient's body can be fully optimized with regard to the compromise between total radiation dose (preferably the lowest possible) and image quality (preferably the highest possible).

[0054] Preferably, the current intensity modulation is maximized so as to also maximize the vertical scan velocity at a constant value.

[0055] Thus, for a given amount of radiation emitted and therefore received by a standing patient during said vertical scan, both are kept at the same level, and the total vertical scan time is significantly reduced, which has the advantage of reducing the possibility of and the effects of movement of a standing patient, thereby somewhat reducing the risk of blurring and distortion of the frontal and lateral images.

[0056] Preferably, said operational mode can be manually turned on or off by an operator of the radiological imaging method.

[0057] Thus, a very advantageous method of operating a radiological imaging device is available which can be cancelled if an operator of said radiological imaging device wants to get rid of it, for example to operate said radiological imaging device fully manually.The radiological imaging method according to an advantageous embodiment of the invention presents three operating modes, namely a fully manual mode, an AEC mode without modulation (AEC=Automatic Exposure Control) and an AEC mode with modulation.

[0058] Preferably, the operating mode can be used for patient morphology types ranging from pediatric to obese adults, is dedicated to vertical scanning of large and / or obese patients, and / or the operating mode is dedicated to vertical scanning of pediatric patients.

[0059] The radiographic imaging method according to the invention is even more interesting when the patient's thickness may be particularly thin or particularly thicker than that of an average-sized patient. This shows that the radiographic imaging method according to the invention is very patient-specific and takes into account a wide attenuation range in long axis imaging. Of course, the radiographic imaging method according to the invention also works very well for standard-sized patients.

[0060] Preferably, said current intensity modulation rate does not exceed a predetermined threshold of 5 mA per millisecond, or does not exceed a predetermined threshold of 2 mA per millisecond, or does not exceed a predetermined threshold of 1 mA per millisecond.

[0061] Thus, the radiation imaging method according to the invention can be carried out with relatively simple and inexpensive radiation sources having relatively slow current intensity drive capabilities.

[0062] Preferably, said current intensity modulation is in the range of at least 20mA to 300mA, preferably in the range of 10mA to 400mA.

[0063] Thus, the radiation imaging method according to the invention can be carried out with relatively simple and inexpensive radiation sources having a relatively limited range of current intensity modulation capabilities.

[0064] Preferably, said voltage intensity modulation is in the range of at least 60 kV to 100 kV, preferably in the range of 50 kV to 130 kV.

[0065] Thus, the radiation imaging method according to the present invention can be implemented with relatively simple and inexpensive radiation sources having a relatively limited range of voltage intensity driving capabilities, while at the same time making full use of the available range of voltage intensity driving capabilities.

[0066] Preferably, the vertical scan speed is in the range of at least 8 cm / sec to 20 cm / sec, preferably in the range of 0.4 cm / sec to 35 cm / sec.

[0067] Thus, the radiation imaging method according to the present invention can be implemented with relatively simple and inexpensive radiation sources having a relatively limited range of vertical scan speed capabilities, while at the same time making full use of the available range of vertical scan speed capabilities.

[0068] Preferably, each of the frontal scout views and / or lateral scout views is created by performing a preparatory vertical scan of a patient standing along a vertical scan direction with a reduced overall radiation dose compared to each of the frontal and lateral images prior to creating each of the frontal and lateral images, preferably the reduced overall radiation is less than 10% of the overall radiation dose, more preferably less than 5% of the overall radiation dose.

[0069] Thus, depending on the thickness profile and the localization of certain bones of the patient's standing body along the vertical scan direction, the modulation of the drive current intensity, and possibly also the modulation of the vertical scan speed, can be determined immediately before performing the vertical scan, which results in effective frontal and lateral images of the standing patient's body, performed with a limited but complete radiation dose sufficient to create high-quality frontal and lateral images. The scout view can be performed at the expense of a very limited overexposure to the emitted radiation. The benefit can even be twofold, not only is the overexposure during the scout view execution (+10% or +5%) very limited, but it is also very efficient to optimize the compromise between the total radiation dose received and the enhancement of the image contrast.

[0070] Preferably, pixels in said scout view are collected by zones of NxN pixels, more preferably ranging from 2x2 pixels to 10x10 pixels, to create imaging zones.

[0071] Thus, the image quality and image contrast of the scout view is improved, despite the very low levels of emitted radiation used to perform this scout view.

[0072] Preferably, the image or the imaging zone is processed to identify corner points, which are then used to calculate the thickness profile and to identify the localization of the particular bone in a patient standing along the vertical scan direction.

[0073] Therefore, from the scout view, it is easier and more efficient to calculate the thickness profile and identify the localization of the specific bones of a standing patient along the vertical scan direction, despite the very low level of radiation dose emitted.

[0074] Preferably, said images or said imaging zones are processed by a neural network to calculate said thickness profile and to identify the localization of said particular bones in a patient standing along said vertical scan direction.

[0075] Therefore, it is easier and more efficient to identify the localization of said particular bone in a patient standing along the vertical scanning direction from the scout view, despite the emitted radiation dose being at a very low level.

[0076] Preferably, the two radiation sources slide vertically to perform a vertical scan of the pelvis or spine or whole body of a standing patient along a vertical scanning direction.

[0077] Preferably, the two radiation detectors are associated with the two radiation sources respectively, and the two radiation detectors are two Photon Counting Detectors (PCDs), each associated with an automatic image processing function that automatically balances the image grey levels whatever the amount of radiation received at the sensitive surface of the radiation detector in order to homogenize the detector response.

[0078] This is an interesting feature since it is difficult for an operator of a radiological imaging method to manually correctly assess over-exposure or under-exposure to the radiation signal emitted by the radiation source. Photon-counting detectors offer improved linearity and signal-to-noise ratio for X-ray flux compared to gas detectors.

[0079] Preferably, the two radiation detectors are associated with the two radiation sources respectively, and the two radiation detectors are two multi-energy counting detectors, preferably two Energy Resolved Photon Counting Detectors (ERPCDs).

[0080] Preferably, the radiation is X-ray.

[0081] A standing patient or a patient in a standing position is a patient in a weight-bearing position, as opposed to a lying patient or a patient in a lying position as in computed tomography. An alternative weight-bearing position for a patient in a standing position is a patient in a sitting position.

[0082] Preferably, the second energy threshold is selected to improve image contrast more for lower patient thickness regions along the vertical direction than for higher patient thickness regions along the vertical direction, preferably the second energy threshold is selected between 50 keV and 90 keV, preferably between 60 keV and 80 keV, more preferably the second energy threshold is selected at 70 keV.

[0083] Thus, even if the patient's broad chest is still accurately seen, the narrow arms or legs are not sacrificed at all by being unsaturated or very slightly saturated, i.e., overexposed due to system limitations.

[0084] Preferably, the first energy threshold and / or the second energy threshold are varied and / or associated spectral filtering, preferably k-edge filtering, is used and adjusted depending on the thickness of the patient's bone and / or the thickness of the patient's soft tissue and / or the localization of a particular bone of the patient at different imaging positions along the vertical scan direction.

[0085] Thus, the accuracy of the end-user images used by the professionals is further improved.

[0086] Preferably, the front image and / or the side image are both monoenergetic images performed with the voltage intensity modulation of the front radiation source and / or the side radiation source, Alternatively, the front image and / or the side image are both multi-energy images performed without voltage intensity modulation of the front radiation source and / or the side radiation source.

[0087] Thus, to obtain good image quality at a reduced total radiation dose, the detector that records the image is simpler but the modulator is more complex, or the detector that records the image is more sophisticated but the modulator is simpler.

[0088] Advantageously, the multi-energy scout view is a dual-energy scout view.

[0089] To all the above mentioned objects of the present invention and / or all the above mentioned combinations, one may add either mechanical cross-scatter correction by vertical gaps as described for example in patent application EP16711889 or US patent application 1607660, and / or software cross-scatter correction as described for example in patent application EP17758269 or US patent application 16628410, all of which are incorporated by reference and owned by the same applicant.

[0090] All the above-mentioned objects and / or all the above-mentioned combinations of the present invention may be supplemented and / or adapted with any conventional signal processing, e.g. any signal pre-processing or signal post-processing as disclosed in patent application WO2021 / 094806 or patent application WO2021 / 094404, which are incorporated by reference and owned by the same applicant.

[0091] The present invention aims to provide a solution for providing an AEC system for a scanning stereo X-ray system, which AEC complies with the IEC 62494-1 standard.

[0092] PMMA is poly(methyl methacrylate), a thermoplastic often used as a replacement for glass. Al is aluminum.

[0093] Further features and advantages of the invention will become apparent from the following description of embodiments of the invention, given as non-limiting examples, with reference to the accompanying drawings listed below, in which: [Brief description of the drawings]

[0094] [Figure 1]FIG. 13 illustrates an example of an imaging workflow of a radiological imaging method according to an embodiment of the present invention with current modulation but without voltage modulation. [Diagram 2] FIG. 13 illustrates another example of an imaging workflow of a radiation imaging method according to an embodiment of the present invention, with both current and voltage modulation. [Diagram 3] 2A-2C show examples of multi-energy scout view acquisition steps within a radiological imaging method according to an embodiment of the present invention; [Figure 4] FIG. 13 illustrates another example of a multi-energy scout view acquisition step within a radiological imaging method according to an embodiment of the present invention. [Diagram 5] FIG. 13 illustrates an example of a bone localization calculation step with profile of interest extraction within a radiological imaging method according to an embodiment of the present invention. [Figure 6] 3A-3C show examples of some of the steps of calculating the thickness of the patient's bones and soft tissues within a radiological imaging method according to an embodiment of the present invention; [Figure 7] 4A-4C show examples of other parts of the calculation step of the patient's bone and soft tissue thickness within a radiological imaging method according to an embodiment of the present invention. [Figure 8] FIG. 1 shows the interrelationship between total thickness, PMMA thickness, and Al thickness. [Figure 9] FIG. 1 illustrates an example of a CNRD calculation step on a search space within a radiological imaging method according to an embodiment of the present invention. [Figure 10] FIG. 2 illustrates an example of an optimal kV mapping step within a radiological imaging method according to an embodiment of the present invention. [Figure 11] FIG. 1 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the present invention, showing a frontal non-normalized image of a patient. [Figure 12] FIG. 2 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the present invention, showing a raw frontal radiological image of a patient. [Figure 13] FIG. 1 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the present invention, showing a frontal normalized image of a patient. [Figure 14]FIG. 1 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the present invention, showing a lateral non-normalized image of a patient. [Figure 15] FIG. 2 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the present invention, showing a raw radiological image of a lateral side of a patient. [Figure 16] FIG. 1 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the present invention, showing a lateral normalized image of a patient. [Figure 17] FIG. 13 shows an example of a single energy scout view with signal vs. PMMA mapping only obtained by a radiological imaging method not according to an embodiment of the present invention. [Figure 18] 1A-1C show examples of multi-energy scout views with PMMA vs. Al mapping and signal vs. Al mapping obtained by a radiological imaging method according to an embodiment of the present invention. [Figure 19] FIG. 13 shows a simulated example of expected tube power profile from both frontal and side mono-energy scout views with current modulation but without voltage modulation, not according to an embodiment of the present invention. [Figure 20] FIG. 20 is a diagram showing an example of a current modulation profile corresponding to FIG. 19. [Figure 21] FIG. 20 is a diagram showing an example of voltage fixed values ​​corresponding to FIG. 19. [Figure 22] FIG. 20 shows an example of a frontal bone localization profile along with a patient profile of interest corresponding to FIG. 19. [Diagram 23] FIG. 20 shows an example of a lateral bone localization profile along with a patient profile of interest corresponding to FIG. 19. [Figure 24] FIG. 13 shows simulation examples of predicted tube power profiles from both frontal and side mono-energy scout views with both current and voltage modulation and without an embodiment of the present invention. [Diagram 25] FIG. 25 is a diagram showing an example of a current modulation profile corresponding to FIG. 24. [Figure 26]FIG. 25 is a diagram showing an example of a voltage modulation profile corresponding to FIG. 24. [Figure 27] FIG. 25 shows an example of a frontal bone localization profile along with a patient profile of interest corresponding to FIG. 24. [Figure 28] FIG. 25 shows an example of a lateral bone localization profile along with a patient profile of interest corresponding to FIG. 24. [Figure 29] FIG. 13 shows simulation examples of predicted tube power profiles with both current and voltage modulation and from both frontal and side multi-energy scout views, according to an embodiment of the present invention. [Diagram 30] FIG. 30 is a diagram showing an example of a current modulation profile corresponding to FIG. 29. [Diagram 31] FIG. 30 is a diagram showing an example of a voltage modulation profile corresponding to FIG. 29. [Diagram 32] FIG. 30 shows an example of a frontal bone localization profile along with a patient profile of interest corresponding to FIG. 29. [Diagram 33] FIG. 30 shows an example of a lateral bone localization profile along with a patient profile of interest corresponding to FIG. 29. [Diagram 34] FIG. 13 shows an example of a frontal bone localization profile along a patient profile of interest in a simulated acquired modulation image. [Diagram 35] FIG. 13 shows an example of a lateral bone localization profile along a patient profile of interest in a simulated acquired modulation image. [Diagram 36] FIG. 13 shows an example of a simulated frontal signal profile along a patient profile of interest. [Figure 37] FIG. 13 shows an example of a simulated frontal deviation index profile along a patient profile of interest. [Figure 38] FIG. 13 shows an example of a simulated lateral signal profile along a patient profile of interest. [Figure 39] FIG. 13 illustrates an example of a simulated lateral deviation index profile along a patient profile of interest. [Diagram 40] 1A and 1B are diagrams illustrating examples of the structure of an imaging device for implementing a radiation imaging method according to an embodiment of the present invention; [Diagram 41] 5A-5C show examples of areas of a detector used for average value calculations during a radiological imaging method according to an embodiment of the present invention; [Diagram 42] FIG. 13 shows an example of optimal kV mapping during a radiological imaging method not according to an embodiment of the present invention, where the scout view is monoenergetic. [Diagram 43] FIG. 13 shows an example of optimal kV mapping during a radiological imaging method according to an embodiment of the present invention, where the scout view is multi-energy. [Diagram 44] FIG. 13 shows an example of a deviation index map for optimal kV mapping during a radiological imaging method not according to an embodiment of the present invention, where the scout view is monoenergetic. [Diagram 45] FIG. 13 shows an example of a deviation index map for optimal kV mapping during a radiological imaging method according to an embodiment of the present invention, where the scout view is multi-energy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0095] In the following description, without any contrary mention, what is said about the frontal scout view or the frontal image can be applied equally to the lateral scout view or the lateral image, respectively, and vice versa. Everything done for both the frontal scout view and the lateral scout view can be done only for the frontal scout view or the lateral scout view, if only the frontal scout view or the lateral scout view is interesting for the specialist or the patient. Everything done for both the frontal image and the lateral image can be done only for the frontal image or the lateral image, if only the frontal image or the lateral image is interesting for the specialist or the patient. If a profile is mentioned, without any contrary mention, a sequence of several partial or regional average values ​​(average values ​​per zone or organ, e.g. average values ​​per leg, pelvis, spine, neck, head or parts thereof) or possibly a single average value may be sufficient, but the result will be less accurate.

[0096] FIG. 1 shows an example of an imaging workflow of a radiological imaging method according to an embodiment of the invention with current modulation but without voltage modulation.

[0097] First, step 1 of acquiring a frontal scout view and a side scout view is performed.

[0098] A step 20 of thickness profile extraction is then performed from the frontal and lateral scout views performed in the acquisition step 1. This step 20 includes a sub-step 21 of bone localization calculation with extraction of a profile of interest along the height of the patient, which is performed simultaneously in parallel with a sub-step 22 of calculation of both the patient's bone thickness and the patient's soft tissue thickness, and then both the patient's bone thickness profile and the patient's soft tissue thickness profile along the height of the patient are processed by extraction of the respective thickness values ​​along the profile of interest coordinates. In sub-step 21, coordinates {x_i}(x_1,x_2...x_N) corresponding to the localization of points in the profile of interest are extracted from the scout views. In sub-step 22, a conversion between signal and thickness is performed, which results in a bone thickness image fBone and a soft tissue thickness image fSoft. The combined result of sub-steps 21 and 22 is a collection of {fBone(x_i)} and {fSoft(x_i)}.

[0099] At the end of the thickness profile extraction step 20, both the patient's bone thickness profile and the patient's soft tissue thickness profile along the patient's height are available for the next step, which is the decision and selection step 23.

[0100] Then, a step 23 of determining fixed voltage values ​​(in kV) and spectral filters and of selecting detector energy thresholds from a model and / or look-up table 24 containing a catalogue of models and / or references is based on the patient's bone thickness profile along the patient's height and the patient's soft tissue thickness profile. The model and / or look-up table 24 provides an exposure target 25 corresponding to the model or reference selected in the determining and selecting step 23. At the end of the determining and selecting step 23, the spectral filtering, fixed voltage values, detector energy threshold(s) are available for the next calculation step 26.

[0101] A calculation step 26 then calculates the acquisition speed of the vertical scan along the height of the standing (or sitting) patient and the current modulation profile along the height of the patient. The calculation step 26 also uses the exposure target 25. The calculation step also performs a feedback loop towards the decision and selection step 24. At the end of the calculation step 26, the spectral filtering, the fixed voltage value, the detector energy threshold(s), the vertical scan acquisition speed (in mm / sec), the current modulation profile along the height of the patient in mA are available for the next image acquisition step 3. The current modulation profile along the height of the patient is also directly available to the image normalization step 4.

[0102] All steps 20 , 23 , 24 , 25 , 26 are part of the exposure parameter calculation routine 2 .

[0103] Then, after this exposure parameter calculation routine 2 is fully completed, an image acquisition step 3 is performed based on spectral filtering, fixed voltage values, one or more detector energy thresholds, vertical scan acquisition speed (in mm / sec), and current modulation profile (in mA) along the patient height. This acquired image can be a single energy image or a multi-energy image. Preferably, this acquired image is a multi-energy image. The acquired image can include a frontal image and / or a lateral image. The acquired image preferably includes a frontal image and a lateral image.

[0104] The acquired front and side images are then normalized in a normalization step 4.

[0105] The normalized front and side images can then be further processed (using post-processing steps) and / or subsequently displayed on a screen for viewing by an expert, in processing and display step 5.

[0106] FIG. 2 shows another example of an imaging workflow of a radiation imaging method according to an embodiment of the present invention, with both current and voltage modulation.

[0107] First, step 1 of acquiring a frontal scout view and a side scout view is performed.

[0108] A thickness profile extraction step 20 is then performed from the frontal and lateral scout views performed in the acquisition step 21. This step 20 includes a sub-step 21 of bone localization calculation with extraction of a profile of interest along the patient's height, which is performed simultaneously in parallel with a sub-step 22 of calculation of both the patient's bone thickness and the patient's soft tissue thickness, both of which are then processed by extraction of the respective thickness values ​​along the profile of interest coordinates. At the end of the thickness profile extraction step 20, both the patient's bone thickness profile and the patient's soft tissue thickness profile along the patient's height are available for the next step, which is a decision and selection step 23.

[0109] Then, a step 23 of determining a voltage modulation profile (in kV = kilovolts) along the patient height and a spectral filter and of selecting a detector energy threshold from a model and / or look-up table 24 containing a catalogue of models and / or references is based on the patient's bone thickness profile and the patient's soft tissue thickness profile along the patient height. The model and / or look-up table 24 provides an exposure target 25 corresponding to the model or reference selected in the determining and selecting step 23. At the end of the determining and selecting step 23, the spectral filtering, the voltage modulation profile along the patient height, the detector energy threshold or thresholds are available for the next calculation step 26.

[0110] A calculation step 26 then calculates the acquisition speed of the vertical scan along the height of the standing (or sitting) patient and the current modulation profile along the height of the patient. The calculation step 26 also uses the exposure target 25. The calculation step also performs a feedback loop towards the decision and selection step 23. At the end of the calculation step 26, the following parameters are calculated: spectral filtering, voltage modulation profile along the height of the patient, one or more detector energy thresholds, vertical scan acquisition speed (in mm / sec), current modulation profile along the height of the patient (in mA). The voltage modulation profile along the height of the patient and the current modulation profile along the height of the patient are also directly available to the image normalization step 4 and also to the following image acquisition step 3.

[0111] All steps 20 , 23 , 24 , 25 , 26 are part of the exposure parameter calculation routine 2 .

[0112] Then, after this exposure parameter calculation routine 2 is fully completed, an image acquisition step 3 is performed based on the spectral filtering, the voltage modulation profile (in kV) along the patient height, one or more detector energy thresholds, the vertical scan acquisition speed (in mm / sec), and the current modulation profile (in mA) along the patient height. This acquired image can be a mono-energy image or can be a multi-energy image. Preferably, this acquired image is a multi-energy image, but can also be a mono-energy image. The acquired image can include a frontal image and / or a lateral image. The acquired image preferably includes a frontal image and a lateral image.

[0113] The acquired front and side images are then normalized in a normalization step 4.

[0114] The normalized front and side images can then be further processed (using post-processing steps) and / or subsequently displayed on a screen for viewing by an expert, in processing and display step 5.

[0115] FIG. 3 illustrates an example of a multi-energy scout view acquisition step within a radiological imaging method according to an embodiment of the present invention.

[0116] The normalized attenuation spectrum AS is expressed as a function of the energy E expressed in keV.

[0117] In the multi-energy scout view mode, the detector directly reads the low-energy and high-energy scout views and infers the full-energy scout view by summing the high-energy and low-energy scout views.

[0118] In mono-energy or single-energy scout view mode, there is only a single bin corresponding to all energy bins.

[0119] FIG. 4 illustrates another example of a multi-energy scout view acquisition step within a radiological imaging method according to an embodiment of the present invention.

[0120] The normalized attenuation spectrum AS is expressed as a function of the energy E expressed in keV.

[0121] In the multi-energy scout view mode, the detector reads the full-energy scout view and the high-energy scout view, and infers the low-energy scout view by subtracting the high-energy scout view from the full-energy scout view.

[0122] In mono-energy or single-energy scout view mode, there is only a single bin corresponding to all energy bins.

[0123] FIG. 5 shows an example of a bone localization calculation step with profile of interest extraction within a radiological imaging method according to an embodiment of the present invention.

[0124] In FIG. 5 there is a scout view 6, here a lateral scout view 6, with corner points 60 positioned along a lateral image 6 of the patient's skeleton, the corner points 60 representing the localization of particular bones of the patient at various imaging positions along the vertical scanning direction, which here is also the height of a standing patient.

[0125] These corner points 60 represent curves extracted from the patient's lateral image 6 by summarizing detector signal values ​​at anatomical landmarks of clinical interest along the slot scan. Several processing techniques can therefore be used, which can be based on landmark extraction from image filtering and segmentation techniques, or machine learning techniques.

[0126] This is how sub-step 21 of the bone localization calculation is performed.

[0127] FIG. 6 shows an example of some of the patient bone and soft tissue thickness calculation steps within a radiological imaging method according to an embodiment of the present invention.

[0128] The sub-steps 22 of calculating both patient thickness and soft tissue thickness are performed each time by the online operation 222 of online thickness calculation 222 in FIG. 6 using information separately obtained offline by the offline operation 221 of offline signal-to-thickness mapping calibration in FIG. 5 .

[0129] In the offline operation 221 of the offline signal-to-thickness mapping calibration, the scout exposure parameters 2211 and the known material thickness 2212 are used as inputs to a measurement or simulation 2213 that gives as output a measured or simulated detector signal 2214. Both the known material thickness 2212 and the measured or simulated detector signal 2214 are then saved and stored in a signal-to-thickness mapping database 2215. The offline calculated signal-to-thickness mapping database 2215 contains mappings from detector signal counts to corresponding material thicknesses. These mappings can be, for example, look-up tables (LUTs) or model fits. In contrast to the single energy scout view where the mapping is based on the total energy signal, the multi-energy scout view mapping, here the dual energy scout view, is based on signal pairs including both low and high energy signals, along with the calculation of one mapping per material, i.e., soft tissue for the low energy signal and bone for the high energy. The thickness of the PMMA is stored in the high and low energy coordinate systems. The AI ​​thickness is stored in the high-energy and low-energy coordinate systems.

[0130] FIG. 7 shows an example of another part of a patient bone and soft tissue thickness calculation step within a radiological imaging method according to an embodiment of the present invention.

[0131] In the online operation 222 of the online thickness calculation, the measured detector signal 2221 is used as input to both a sub-database storing signal vs. bone thickness mappings 2222 and a sub-database storing signal vs. soft tissue thickness mappings 2224. The sub-database storing signal vs. bone thickness mappings 2222 provides as output a bone thickness profile 2223. The sub-database storing signal vs. soft tissue thickness mappings 2224 provides as output a soft tissue thickness profile 2225.

[0132] 8 shows the interrelationship between total thickness, PMMA thickness, and Al thickness. In the phantom or avatar used to construct the signal-to-thickness mapping database 2215, which includes both the signal-to-bone subdatabase 2222 and the soft tissue mapping subdatabase 2224, the total thickness T PMMA+Al 230 is T PMMA 232 and T Al 231. In the imaged patient's body and in the corresponding images processed using the signal-to-thickness mapping database 2215, which includes both the signal-to-bone sub-database 2222 and the soft tissue mapping sub-database 2224, the total thickness T soft tissue+bone 230 is T soft tissue 232 and T bone It is equal to the sum of 231.

[0133] The step 23 of determining the voltage modulation profile (in kV = kilovolts) and the spectral filter along the patient height and of selecting the detector energy threshold from a model and / or lookup table 24 containing a catalogue of models and / or references is based on a mapping from material thickness to voltage values ​​expressed in kV (kilovolts) based on the patient's bone thickness profile and the patient's soft tissue thickness profile along the patient's height. This mapping can be given by an empirically tuned lookup table as a first alternative or can be optimally determined according to a task metric as a second alternative.

[0134] In a second alternative, the task metric preferably follows the following rule at best: be invariant with respect to product tube current with exposure time, or at least be a monotonic function of product tube current (expressed in milliamp seconds, mAs) with exposure time; expresses how good the task performance is as a function of voltage and material thickness (material thickness is a one-dimensional vector for single energy scout views, or a multi-dimensional vector for multi-energy scout views as in the present invention); the better the task, the higher the metric; It is meaningful across the entire slot scan, i.e., along the entire interest profile, should be satisfied.

[0135] This task metric is

[0136]

number

[0137] where:

[0138]

number

[0139] is a vector of additional data-dependent parameters such as single-material or multi-material thickness profiles or tube spectrum filtering options for image acquisition. The selection of the optimal voltage kV is

[0140]

number

[0141] is equivalent to selecting

[0142] This mapping is calculated offline and stored, for example, either as a look-up table or as a model fit. Along with this mapping, a mapping of detector exposure target (e.g., detector signal) per product tube current by exposure time (in mAs)

[0143]

number

[0144] are also stored, for example, either as a lookup table or as a model fit.

[0145]

number

[0146] is used in the task metrics.

[0147] By way of illustration, a specific example of a task metric used for voltage kV optimization for the dual energy scout view case is described herein: CNR to dose ratio (CNRD).

[0148] As an example, consider two material bases (PMMA, Al) provided by a dual energy scout view.

[0149] The task has two components: Maximizing the local contrast resolution of the Al material surrounded by PMMA; (PMMA, Al) Minimizing the entrance dose required to achieve a unit detector signal value behind the projection line (corresponding to the ALARA principle) It is.

[0150] The local contrast resolution can be measured by the contrast-to-noise ratio (CNR).

[0151]

number

[0152]

number

[0153]

number

[0154] The entrance dose can be monitored by using the spectral air kerma value D.

[0155] The CNRD:

[0156]

number

[0157] It is defined as:

[0158] This is independent of the product tube current due to exposure time.

[0159] FIG. 9 illustrates an example of a CNRD calculation step on a search space within a radiological imaging method according to an embodiment of the present invention.

[0160] For a particular voltage value, a database of CNRD maps 234, each of which is a function of both Al thickness and PMMA thickness, is searched.

[0161] FIG. 10 illustrates an example of an optimal kV mapping step within a radiological imaging method according to an embodiment of the present invention.

[0162] A database of CNRD maps 234 was searched to obtain an optimum voltage (kV) map 235, which is a map showing the optimum voltage to use as a function of both Al thickness and PMMA thickness.

[0163] The optimization shown in both Figures 9 and 10 works as follows: Either by using simulation or by making measurements in the system (or by using a hybrid method) PMMA ,T Al ) Explore space offline,

[0164]

number

[0165] Guess.

[0166] If the equivalent thickness material used is PMMA, then (using data extrapolation) kV(T PMMA , 0) one can infer the optimal voltage (in kV) value for a single-energy scout view.

[0167] Here, for simplicity, only the kV space (p=kV) is optimized for a fixed spectral filter and a fixed detector energy threshold. However, if the optimization is performed for a multi-valued parameter, e.g., p=(kV, Filter, Thresholds), the rationale remains the same: The search space (p,T PMMA ,T Al ) and Next,

[0168]

number

[0169] Calculate.

[0170] A calculation step 26 performs a calculation of the acquisition speed for a vertical scan along the height of a standing (or sitting) patient and a calculation of the current modulation profile along the height of the patient.

[0171] The current profile and vertical scan rate selection strategy for a given voltage value or a given voltage profile is similar to the strategy used in patent application WO2021 / 094806 (herein incorporated by reference) and can be summarized as follows: Calculation of the exposure budget (the current needed to reach the exposure target multiplied by the exposure time); Maximizing vertical scan speed given an available tube current budget (constrained by hardware specifications in terms of minimum and maximum tube power and minimum and maximum instantaneous current values); Calculation of the corresponding current profile therefrom It is.

[0172] Parameters

[0173]

number

[0174] Given the optimal voltage values ​​for a set of (including thickness profile), the target signal S T The product of the current and exposure time required to reach

[0175]

number

[0176] It is.

[0177] The exposure time t is given by the highest current value that can be used for a given current value, taking into account tube power limitations and lower and upper current limits. The acquisition speed is selected (either as a free value or from a set of allowable system speeds) as the smallest speed among those calculated along the thickness profile. The current value is then updated to match the target signal given this fixed acquisition speed.

[0178] Whenever the current value falls below the current boundary by more than the current boundary, the voltage may be lowered or raised, respectively, to bring it back into the acceptable range of values ​​until the voltage value reaches its lower and / or upper limit. Matching the target signal has priority over maintaining an optimal voltage value, and this priority is met by virtue of this feedback loop from step 26 to step 23 (see Figures 1 and 2).

[0179] Once the optimal exposure parameters are selected, their profile along the slot scan can be further adapted to hardware constraints (e.g., in the slope of the current and voltage profiles) if these constraints have not already been taken into account in the previous step. The exposure parameters can then be formatted into a file readable by the system to perform image acquisition step 3 (see Figures 1 and 2).

[0180] Figures 11 to 16 show the effect of normalization step 4. The accurate data normalization step 4 (see Figures 1 and 2) may involve either additional air measurements with the same exposure technique (up to a factor in the current value), or simulation, or a hybrid method combining online image acquisition with simulation. Although it is sufficient to normalize the image acquisition with the air measurements (also called "raw radiation"), this normalization step 4 may advantageously also include image processing algorithms to take into account system variability. Once the normalization step 4 has been performed, a standard image processing pipeline may be used.

[0181] 11 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the invention, showing a frontal non-normalized image of a patient. A frontal non-normalized image 41 of a patient is present.

[0182] 12 illustrates an example of a normalization step within a radiographic imaging method according to an embodiment of the invention, showing a frontal raw radiographic image of a patient. There is a frontal raw radiographic image 42, which is a frontal image of air without a patient.

[0183] 13 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the invention, showing a frontal normalized image of the patient. There is a frontal normalized image 43 of the patient, which is obtained by dividing the frontal non-normalized image 41 of the patient by the frontal raw radiological image 42.

[0184] 14 illustrates an example of a normalization step within a radiological imaging method according to an embodiment of the invention, showing a lateral non-normalized image 44 of a patient.

[0185] 15 illustrates an example of a normalization step within a radiography method according to an embodiment of the invention showing a lateral raw radiography image of a patient. There is a lateral raw radiography image 45 which is a lateral image of air without a patient.

[0186] 16 illustrates an example of a normalization step within a radiography method according to an embodiment of the present invention, showing a lateral normalized image of a patient. There is a lateral normalized image 46 of the patient, which is obtained by dividing the lateral non-normalized image 44 of the patient by the lateral raw radiography image 45.

[0187] 17 to 39 show simulation results of a radiographic imaging method according to an embodiment of the present invention.

[0188] A simulated voxelized anthropomorphic phantom made of PMMA and Al is used. Thickness profiles are extracted in both frontal and lateral scout views and used to calculate exposure parameters.

[0189] The simulated cases are With fixed voltage, With modulation voltage, Mono-energy scout view leading to tube current modulation, Dual energy scout view (as in the present invention) with modulation voltage leading to tube current modulation It is.

[0190] An exposure quality assessment is performed, A profile of interest is extracted (as described in the bone localization calculation substep 21 in Fig. 1 and Fig. 2) and the signal profile is thus the smoothed image detector signal along this profile of interest, denoted S; The local deviation index profile is

[0191]

number

[0192] is calculated as The overall deviation index value is

[0193]

number

[0194] where X(S) represents the central tendency of S along the profile of interest, such as the mean M(S) or median m(S) according to the IEC 62494-1 standard. The closer the deviation index is to zero, the higher the exposure quality.

[0195] The simulation results are as follows: The fixed voltage case leads to underexposed areas where bone dominates over PMMA (e.g., the patient's neck and the patient's legs); Voltage modulation with a PMMA-only thickness profile brings the signal profile closer to its target, but still misses the target in the lower regions. Voltage modulation with both PMMA and Al thickness profiles results in a flatter signal profile with deviation exponents closer to zero. Shows.

[0196] FIG. 17 shows an example of a single energy scout view with only signal vs. PMMA mapping obtained by a radiological imaging method not according to an embodiment of the present invention.

[0197] Curves 301 and 302 show thickness profiles tp along a distance d from the patient's vertex (top of the head) which corresponds to the patient's height. Curve 301 shows the frontal soft tissue thickness profile along the patient's height. Curve 302 shows the lateral soft tissue thickness profile along the patient's height.

[0198] FIG. 18 shows examples of multi-energy scout views with signal vs. PMMA and signal vs. Al mapping obtained by a radiological imaging method according to an embodiment of the present invention.

[0199] Curves 311, 312, 313, and 314 show thickness profiles tp along a distance d from the patient's vertex (top of the head), which is also the patient's height (starting at the patient's vertex). Curve 311 shows a frontal soft tissue thickness profile along the patient's height. Curve 312 shows a lateral soft tissue thickness profile along the patient's height. Curve 313 shows a frontal bone thickness profile along the patient's height. Curve 314 shows a lateral bone thickness profile along the patient's height.

[0200] 19 shows a simulated example of expected tube power profile from both frontal and side mono-energy scout views with current modulation but without voltage modulation, not according to an embodiment of the invention. The vertical scan speed is 45 mm / sec.

[0201] Curve 321 shows the front tube power profile P along distance d from the patient's apex. Curve 322 shows the side tube power profile P along distance d from the patient's apex. Horizontal line 320 shows the tube power limit that cannot be exceeded without saturating. The maximum tube power limit is 42 kW.

[0202] Figure 20 shows an example of a current modulation profile corresponding to Figure 19. The vertical scan speed is 45 mm / sec.

[0203] Curve 331 shows the frontal tube current profile I along a distance d from the patient's apex. Curve 332 shows the lateral tube current profile I along a distance d from the patient's apex. Horizontal line 330 indicates the tube current limit that cannot be exceeded without saturation. Available tube current ranges from a minimum of 10 mA to a maximum of 400 mA.

[0204] Figure 21 shows an example of voltage clamp values ​​corresponding to Figure 19. The vertical scan speed is 45 mm / sec.

[0205] Horizontal line 340 indicates a fixed tube voltage that remains constant along the patient height. Available tube voltages range from a minimum of 50 kV to a maximum of 130 kV.

[0206] Figure 22 shows an example of a frontal bone localization profile along the patient height corresponding to Figure 19. The vertical scan speed is 45 mm / sec.

[0207] Curve 350 shows the frontal bone localization along distance d from the vertex (top of the head) of the patient and width w of the patient.

[0208] The grey areas correspond to profile points reaching the lower and / or upper limits of the system, which correspond to the grey lined frontal zones 351 and lateral zones 361 in the frontal and lateral images of Figures 22 and 23, respectively (bone localization profiles 350 and 360 are shown as dashed lines), where multiple large frontal zones 351 can be seen.

[0209] Figure 23 shows an example of a lateral bone localization profile along the patient profile of interest corresponding to Figure 19. The vertical scan speed is 45 mm / sec.

[0210] Curve 360 ​​shows the lateral bone localization along distance d from the vertex (top of the head) of the patient and thickness th of the patient.

[0211] The grey areas correspond to profile points reaching the lower and / or upper limits of the system, which correspond to the grey lined frontal zones 351 and lateral zones 361 in the frontal and lateral images of Figures 22 and 23, respectively (bone localized profiles 350 and 360 are shown as dashed lines), where multiple large lateral zones 361 can be seen.

[0212] 24 shows simulated examples of predicted tube power profiles from both frontal and side mono-energy scout views with and without current and voltage modulation, the vertical scan speed being 45 mm / sec.

[0213] Curve 371 shows the front tube power profile P along distance d from the patient's apex. Curve 372 shows the side tube power profile P along distance d from the patient's apex. Horizontal line 370 shows the tube power limit that cannot be exceeded without saturating. The maximum tube power limit is 42 kW.

[0214] Figure 25 shows an example of a current modulation profile corresponding to Figure 24. The vertical scan speed is 45 mm / sec.

[0215] Curve 381 shows the frontal tube current profile I along a distance d from the patient's apex. Curve 382 shows the lateral tube current profile I along a distance d from the patient's apex. Horizontal line 380 shows the tube current limit that cannot be exceeded without saturation. Available tube current ranges from a minimum of 10 mA to a maximum of 400 mA.

[0216] Figure 26 shows an example of a voltage modulation profile corresponding to Figure 24. The vertical scan speed is 45 mm / sec.

[0217] Curve 391 shows the frontal tube voltage profile V along a distance d from the patient's apex. Curve 392 shows the lateral tube voltage profile V along a distance d from the patient's apex. Horizontal line 390 indicates the tube voltage limit that cannot be exceeded without saturation. Available tube voltages range from a minimum of 50 kV to a maximum of 130 kV.

[0218] Figure 27 shows an example of a frontal bone localization profile along with a patient profile of interest corresponding to Figure 24. The vertical scan speed is 45 mm / sec.

[0219] Curve 400 shows the frontal bone localization along distance d from the vertex (top of the head) of the patient and width w of the patient.

[0220] The grey areas correspond to profile points reaching the lower and / or upper limits of the system, which correspond to the lateral zones 411 delineated in grey in the lateral image of Figure 28 (bone localization profiles 400 and 410 are shown as dashed lines), where no frontal zones are visible.

[0221] Figure 28 shows an example of a lateral bone localization profile along the patient profile of interest corresponding to Figure 24. The vertical scan speed is 45 mm / sec.

[0222] Curve 410 shows the lateral bone localization along distance d from the vertex (top of the head) of the patient and thickness th of the patient.

[0223] The grey areas correspond to profile points where the lower and / or upper limits of the system are reached, which correspond to the lateral zones 411 outlined in grey in the lateral image of Figure 28 (bone localization profiles 400 and 410 are shown as dashed lines). Here, a unique but somewhat large lateral zone 411 is present.

[0224] 29 shows examples of simulated predicted tube power profiles from both frontal and side mono-energy scout views, with both current and voltage modulation, according to an embodiment of the invention. The vertical scan speed is 45 mm / sec.

[0225] Curve 421 shows the front tube power profile P along distance d from the patient's apex. Curve 422 shows the side tube power profile P along distance d from the patient's apex. Horizontal line 420 shows the tube power limit that cannot be exceeded without saturating. The maximum tube power limit is 42 kW (kW = kilowatts).

[0226] Figure 30 shows an example of a current modulation profile corresponding to Figure 29. The vertical scan speed is 45 mm (mm = millimeter) / sec.

[0227] Curve 431 shows the frontal tube current profile I along a distance d from the patient's apex. Curve 432 shows the lateral tube current profile I along a distance d from the patient's apex. Horizontal line 430 shows the tube current limit that cannot be exceeded without saturation. Available tube current ranges from a minimum of 10 mA to a maximum of 400 mA.

[0228] Figure 31 shows an example of a voltage modulation profile corresponding to Figure 29. The vertical scan speed is 45 mm / sec.

[0229] Curve 441 shows the frontal tube voltage profile V along a distance d from the patient's apex. Curve 442 shows the lateral tube voltage profile V along a distance d from the patient's apex. Horizontal line 440 shows the tube voltage limit that cannot be exceeded without saturation. Available tube voltages range from a minimum of 50 kV to a maximum of 130 kV.

[0230] Figure 32 shows an example of a frontal bone localization profile along with a patient profile of interest corresponding to Figure 29. The vertical scan speed is 45 mm / sec.

[0231] Curve 450 shows the frontal bone localization along distance d from the vertex (top of the head) of the patient and width w of the patient.

[0232] The grey areas correspond to profile points reaching the lower and / or upper limits of the system, which correspond to the lateral zones 461 delineated in grey in the lateral image of Figure 33 (bone localization profiles 450 and 460 are shown as dashed lines), where no frontal zones are visible.

[0233] Figure 33 shows an example of a lateral bone localization profile along the patient profile of interest corresponding to Figure 29. The vertical scan speed is 45 mm / sec.

[0234] Curve 460 shows the lateral bone localization along distance d from the vertex (top of the head) of the patient and thickness th of the patient.

[0235] The grey regions correspond to profile points reaching the lower and / or upper limits of the system, which correspond to the lateral zone 461 outlined in grey in the lateral image of Figure 33 (bone localization profiles 450 and 460 are shown as dashed lines), where a unique and relatively narrow lateral zone 461 exists.

[0236] 34 shows an example of a frontal bone localization profile along a patient profile of interest in a simulated acquired modulation image: Frontal bone localization profile 470 along patient height d and patient width w.

[0237] 35 shows an example of a lateral bone localization profile along a patient profile of interest in a simulated acquired modulation image: Lateral bone localization profile 480 along patient height d and patient thickness th.

[0238] 36 shows an example of a simulated frontal signal profile along a patient profile of interest. The frontal signal profile in counts nc along the patient height d is given by the following curve: Reaching target 500, Curve 501 of a mono-energy scout view with current modulation and without voltage modulation, which gives the worst results; Curves 502 of a mono-energy scout view with current modulation and with voltage modulation, giving intermediate results; The best results are given by the multi-energy (here dual-energy) scout view curves 503 with current modulation and with voltage modulation where M is the mean and m is the median.

[0239] FIG. 37 shows an example of a simulation of the frontal deviation index profile along a patient profile of interest.

[0240] The frontal deviation index profile, expressed as the deviation index DI along the patient height d, is given by the following curve: Target to reach 510, curves 514, which correspond to deviations of +1 or -1 respectively from the target 510; Curve 511 of a mono-energy scout view with current modulation and without voltage modulation, which gives the worst results; Curves 512 of a mono-energy scout view with current modulation and with voltage modulation, giving intermediate results; The best results are given by the multi-energy (here dual-energy) scout view curves 513 with current modulation and with voltage modulation where M is the mean and m is the median.

[0241] FIG. 38 shows an example of a simulation of the lateral signal profile along a patient profile of interest.

[0242] The lateral signal profile in counts nc along the patient height d (starting from the patient apex) is given by the following curve: Target to reach 520, Curve 521 of a mono-energy scout view with current modulation and without voltage modulation, which gives the worst results; Curves 522 of a mono-energy scout view with current modulation and with voltage modulation, giving intermediate results; The best results are given by the multi-energy (here dual-energy) scout view curves 523 with current modulation and with voltage modulation where M is the mean and m is the median.

[0243] FIG. 39 shows an example of a simulation of the Lateral Deviation Index profile along a patient profile of interest.

[0244] The lateral deviation index profile, denoted by the deviation index DI along the patient height d (starting from the patient's apex), is given by the following curve: Target reached: 530; curves 534, which correspond to deviations of +1 or -1 respectively from the target 530; Curve 531 of a mono-energy scout view with current modulation and without voltage modulation, which gives the worst result; Curves 532 of a single energy scout view with current modulation and with voltage modulation, giving intermediate results; The best results are given by the multi-energy (here dual-energy) scout view curves with current modulation and with voltage modulation 533 where M is the mean and m is the median.

[0245] 40 to 45 show experimental results of a radiographic imaging method according to an embodiment of the present invention.

[0246] Fig. 40 shows an example of the structure of an imaging device for implementing a radiation imaging method according to an embodiment of the present invention. The vertical scan direction is orthogonal to the plane of Fig. 40. The patient height is also orthogonal to the plane of Fig. 40. The vertical scan direction is the patient height scan direction, and therefore the scan direction along the patient height for a standing patient.

[0247] There is a phantom 110 comprising a PMMA portion 111 and an Al portion 112 , the phantom 110 being positioned over an imaging zone 107 of an imaging apparatus or device 109 .

[0248] The front emission and reception line includes a front tube 101 which emits a front beam of X-rays 105 which passes through a phantom 110 and reaches a front detector 102 .

[0249] The side emission and receiving line includes a side tube 103 which emits an X-ray side beam 106 that passes through the phantom 110 and reaches a side detector 104 .

[0250] To avoid cross-scattering in the intersection zone 108, mechanical compensation due to vertical gaps between the front emission and reception lines and the side emission and reception lines, and / or software cross-scatter compensation between the front emission and reception lines and the side emission and reception lines can be used, as described above.

[0251] 41 shows an example of a region of a detector used for average value calculation during a radiological imaging method according to an embodiment of the present invention. Zone 120 is the region used for average signal value calculation.

[0252] The process for obtaining experimental results is as follows: Combining a known PMMA thickness with a known Al-1100 thickness, Obtain the equivalent PMMA thickness from a single energy scout view, (For monoenergetic scout views) Acquire monoenergetic images using values ​​of voltage, current, and vertical scan speed given by the equivalent PMMA thickness, In this case, signal-to-thickness mapping maps the full-energy scout view to the thickness of the PMMA, and this mapping is then used online to (For dual-energy scout view) Acquire a monoenergetic image using the voltage, current, and vertical scan speed values ​​given by the (PMMA, Al) thickness pair. As shown in FIG. 41, the average signal value in the central part of the image, indicated as M(S), is measured; Calculate a deviation index between this value and the target signal value, the deviation index being:

[0253]

number

[0254] is defined as Here, S T is the target detector signal value, and the closer the deviation index is to zero, the higher the exposure quality.

[0255] The experimental results are: The further the setup deviates from the single energy scout view based model (PMMA dominated), the further the deviation index deviates from zero. On the other hand, knowledge of the (PMMA, Al) thicknesses from the dual-energy scout view-based model stabilizes the deviation index around zero, regardless of the tested setup. By showing the high interest of the dual energy scout view.

[0256] FIG. 42 shows an example of optimal kV mapping during a radiological imaging method not according to an embodiment of the present invention, where the scout view is monoenergetic.

[0257] For each setup, the optimal voltage (kV) value is calculated from the single energy based equivalent PMMA thickness vector using the CNRD based kV map. The grey scale of the spots 601 in the grid corresponds to the value of the voltage on the vertical voltage bar on the right. Various couples of Al thickness th1 and PMMA thickness th2 are assumed. Lower voltages are used for lower PMMA thicknesses and higher voltages are used for higher PMMA thicknesses.

[0258] FIG. 43 shows an example of optimal kV mapping during a radiological imaging method according to an embodiment of the present invention, where the scout view is multi-energy.

[0259] For each setup, the optimal voltage (kV) value is calculated from the dual energy based (PMMA, Al) thickness vector pair using the CNRD based kV map. The grey scale of the spots 602 in the grid corresponds to the value of the voltage on the right vertical voltage bar. Various couples of Al thickness th1 and PMMA thickness th2 are envisaged: lower voltages are used for lower PMMA thicknesses and somewhat lower Al thicknesses, higher voltages are used for higher PMMA thicknesses and somewhat higher Al thicknesses.

[0260] FIG. 44 shows an example of a deviation index map for optimal kV mapping during a radiological imaging method not according to an embodiment of the present invention, where the scout view is monoenergetic.

[0261] Small deviation indexes are represented by circles, medium deviation indexes by squares and large deviation indexes by triangles. The grey scale of the spots 603 in the grid corresponds to the value of the deviation index on the vertical deviation index bar on the right. Various couples of Al thickness th1 and PMMA thickness th2 are assumed. Lower deviation index values ​​are obtained for higher PMMA thicknesses, lower deviation index values ​​are obtained also for lower Al thicknesses, higher deviation index values ​​are obtained for lower PMMA thicknesses and higher deviation index values ​​are obtained also for higher Al thicknesses. Some spots 603 are circular, but most of them are square or triangular, which is not optimal. With only knowledge of the equivalent PMMA thickness from the single energy scout view, the deviation index becomes inaccurate whenever the Al contribution dominates with respect to PMMA (squares and triangles).

[0262] The non-monotonic results at higher Al thicknesses around 15–20 cm PMMA can be explained by the variable selection of kV values.

[0263] FIG. 45 shows an example of a deviation index map for optimal kV mapping during a radiological imaging method according to an embodiment of the present invention, where the scout view is multi-energy.

[0264] Small deviation indices are represented by circles, medium deviation indices by squares, and large deviation indices by triangles. The grey scale of the spots 604 in the grid corresponds to the value of the deviation indices on the right vertical deviation index bar. Various couples of Al thickness th1 and PMMA thickness th2 are assumed. Small and therefore good deviation index values ​​are obtained for both high and low PMMA thicknesses, and also for both high and low Al thicknesses. All spots 604 are circular and optimal. In FIG. 45, knowledge of the (Al, PMMA) thicknesses from the dual energy scout view provides exposure parameters that lead to deviation indices much closer to zero and therefore significantly better than in FIG. 44.

[0265] The invention has been described with reference to preferred embodiments, however, many variations are possible within the scope of the invention. [Explanation of symbols]

[0266] 6 Side image, scout view, side scout view 24 Models and / or Reference Tables 25 Exposure Target 41 Patient frontal non-normalized images 42 Frontal raw radiographic image 43 Patient frontal normalized images 44 Patient Lateral Non-Normalized Images 45 Lateral raw radiographic image 46 Patient Lateral Normalized Images 60 Corner Points 101 Front tube 102 Front detector 103 Side pipe 104 Side Detector 105 X-ray front beam 106 X-ray side beam 107 Imaging Zone 108 Intersection Zone 109 Imaging equipment or imaging device 110 Phantom 110 Phantom 111 PMMA part 112 Al part 120 Zone 221 Offline operation 222 Online thickness calculation, online operation 230 Total thickness T PMMA+Al 231T Al 232T PMMA 234 CNRD Map 235 Optimal Voltage (kV) Map 301 curve 302 curve 311 Curve 312 curve 313 Curve 314 Curve 320 horizontal line 321 Curve 322 curve 330 horizontal line 331 Curve 332 curve 340 horizontal line 350 curve, bone localization profile 351 Front Zone 360 Bone localization profile, curve 361 Side Zone 370 horizontal line 371 Curve 372 curve 380 horizontal line 381 Curve 382 curve 390 horizontal line 391 Curve 392 curve 400 curves, bone localization profile 410 Bone localization profile, curve 411 Side Zone 420 horizontal line 421 Curve 422 Curve 430 horizontal line 431 Curve 432 curve 440 horizontal line 441 Curve 442 Curve 450 curve, bone localization profile 460 Bone localization profile, curve 461 Side Zone 470 Frontal Bone Localization Profile 480 Lateral Bone Localization Profile 500 Target 501 curve 502 curve 503 curve 510 Target 511 Curve 512 curve 513 Curve 514 Curve 520 Target 521 Curve 522 curve 523 Curve 530 Target 531 Curve 532 curve 533 Curve 534 Curve 601 Spot 602 Spot 603 Spot 604 Spot 2211 Scout Exposure Parameters 2212 known material thickness 2213 Measurement or Simulation 2214 Measured or Simulated Detector Signal 2215 Signal to Thickness Mapping Database 2221 Measured detector signal 2222 Signal-to-Bone Subdatabase 2223 Bone Thickness Profile 2224 Soft Tissue Mapping Sub-Database 2225 Soft Tissue Thickness Profile

Claims

1. two radiation sources (101, 103) having mutually orthogonal imaging directions, one frontal radiation source (101) and one lateral radiation source (103), sliding vertically to perform a vertical scan of a patient standing along a vertical scanning direction; two radiation detectors (102, 104), one frontal radiation detector (102) and one lateral radiation detector (104), respectively associated with the two radiation sources (101, 103), sliding vertically to perform a vertical scan of a patient standing along the vertical scan direction, at least one of the frontal radiation detectors (102, 104) being a multi-energy counting detector; Including, The radiological method includes at least one mode of operation, the at least one mode of operation comprising: A frontal multi-energy scout view is created (1) by performing a preliminary vertical scan of a patient standing along the vertical scan direction with the frontal radiation source (101) and the frontal radiation detector (102), such that the frontal radiation detector (102) detects at least: a first frontal scout view, referred to as a low-energy frontal scout view, received by the frontal radiation detector (102) and corresponding to a first portion of energy below a first given energy threshold; a second frontal scout view, referred to as a high energy frontal scout view, corresponding to a second portion of the energy received by the frontal radiation detector (102) that is above a second given energy threshold; Given The first frontal scout view and the second frontal scout view At least the patient's bone thickness (22) and at least the thickness of the patient's soft tissue (22); localization (21) of specific bones of the patient at different imaging positions along the vertical scan direction; (20) are combined and processed to evaluate A frontal image is created by performing a vertical scan of a standing patient along the vertical scan direction with the frontal radiation source (101) and the frontal radiation detector (102) (3); a modulation of the drive current intensity of at least the frontal radiation source (101) along the vertical scan direction is dependent on a thickness of the patient's bones, a thickness of the patient's soft tissues, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; Preferably, the modulation of the driving voltage intensity of the frontal radiation source (101) along the vertical scan direction depends on a bone thickness of the patient, on a thickness of the soft tissue of the patient, and on a localization of a particular bone of the patient at different imaging positions along the vertical scan direction, the driving current intensity of the front radiation source (101) is automatically performed without voltage intensity modulation of the front radiation source (101); a total radiation dose received by a patient during said vertical scan; for the en face image, local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; or, Both the driving current intensity modulation and the driving voltage intensity modulation of the front radiation source (101) are performed simultaneously, preferably synchronously and automatically; a total radiation dose received by a patient during said vertical scan; for the en face image, local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; A radiation imaging method that improves the compromise between:

2. two radiation sources (101, 103) having mutually orthogonal imaging directions, one frontal radiation source (101) and one lateral radiation source (103), sliding vertically to perform a vertical scan of a patient standing along a vertical scanning direction; two radiation detectors (102, 104), one front radiation detector (102) and one side radiation detector (104), respectively associated with the two radiation sources (101, 103), sliding vertically to perform a vertical scan of a patient standing along the vertical scan direction, at least one of the side radiation detectors (104) being a multi-energy counting detector; Including, The radiological method includes at least one mode of operation, the at least one mode of operation comprising: A lateral multi-energy scout view is created (1) by performing a preliminary vertical scan of a patient standing along the vertical scan direction with the lateral radiation source (103) and the lateral radiation detector (104), such that the lateral radiation detector (104) detects at least: a first side scout view, referred to as a low-energy side scout view, received by the side radiation detector (104) and corresponding to a first portion of energy below a first given energy threshold; a second side scout view, referred to as a high energy side scout view, corresponding to a second portion of the energy received by the side radiation detector (104) that is above a second given energy threshold; Given The first side scout view and the second side scout view At least the patient's bone thickness (22) and at least the thickness of the patient's soft tissue (22); localization (21) of specific bones of the patient at different imaging positions along the vertical scan direction; (20) are combined and processed to evaluate A lateral image is generated (3) by performing a vertical scan of a standing patient along the vertical scan direction with the lateral radiation source (103) and the lateral radiation detector (104); a modulation of the drive current intensity of at least the side radiation source (103) along the vertical scan direction is dependent on a thickness of the patient's bones, a thickness of the patient's soft tissues, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; Preferably, the modulation of the drive voltage intensity of the side radiation source (103) along the vertical scan direction depends on a thickness of the patient's bones, a thickness of the patient's soft tissues, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction, The driving current intensity modulation of the side radiation source (103) is automatically performed without voltage intensity modulation of the side radiation source (103); a total radiation dose received by a patient during said vertical scan; for the lateral images, local image contrasts of the identified specific bone localizations at different imaging positions along the vertical scan direction; or, Both the driving current intensity and the driving voltage intensity of the side radiation source (103) are automatically adjusted simultaneously, preferably synchronously, a total radiation dose received by a patient during said vertical scan; for the lateral images, local image contrasts of the identified specific bone localizations at different imaging positions along the vertical scan direction; A radiation imaging method that improves the compromise between:

3. two radiation sources (101, 103) having mutually orthogonal imaging directions, one frontal radiation source (101) and one lateral radiation source (103), sliding vertically to perform a vertical scan of a patient standing along a vertical scanning direction; two radiation detectors (102, 104), one front radiation detector (102) and one side radiation detector (104), respectively associated with the two radiation sources (101, 103), sliding vertically to perform a vertical scan of a patient standing along the vertical scan direction, the two radiation detectors (102, 104) being two multi-energy counting detectors respectively; Including, The radiological method includes at least one mode of operation, the at least one mode of operation comprising: A frontal multi-energy scout view and a lateral multi-energy scout view are generated (1) by performing a preliminary vertical scan of a patient standing along the vertical scan direction with the frontal and lateral radiation sources (101, 103) and the frontal and lateral radiation detectors (102, 104), such that the frontal and lateral radiation detectors (102, 104) detect at least: a first frontal scout view, referred to as a low-energy frontal scout view, received by the frontal radiation detector (102) and corresponding to a first portion of energy below a first given energy threshold; a second frontal scout view, referred to as a high-energy frontal scout view, received by the frontal radiation detector (102) and corresponding to a second portion of the energy above a second given energy threshold; a first side scout view, referred to as a low-energy side scout view, received by the side radiation detector (104) and corresponding to a first portion of energy below a first given energy threshold; a second side scout view, referred to as a high energy side scout view, corresponding to a second portion of the energy received by the side radiation detector (104) that is above a second given energy threshold; Given the first front scout view and the first side scout view and the second front scout view and the second side scout view; At least the patient's bone thickness (22) and at least the thickness of the patient's soft tissue (22); localization (21) of specific bones of the patient at different imaging positions along the vertical scan direction; (20) are combined and processed to evaluate a frontal image is produced by performing a vertical scan of the patient standing along the vertical scan direction with the frontal radiation source (101) and the frontal radiation detector (102) (3), and a lateral image is produced by performing a vertical scan of the patient standing along the vertical scan direction with the lateral radiation source (103) and the lateral radiation detector (104), both the frontal image and the lateral image being produced during the same vertical scan; a modulation of the drive current intensity of both the front radiation source and the side radiation source (101, 103) along the vertical scan direction is dependent on a thickness of the patient's bones, a thickness of the patient's soft tissues, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction; Preferably, the modulation of the driving voltage intensity of both the front radiation source and the side radiation source (101, 103) along the vertical scan direction depends on a thickness of the patient's bones, a thickness of the patient's soft tissues, and a localization of a particular bone of the patient at different imaging positions along the vertical scan direction, a drive current intensity modulation of the front radiation source (101) is automatically performed simultaneously, preferably synchronously, without a voltage intensity modulation of the front radiation source (101), and a drive current modulation of the side radiation source (103) is automatically performed simultaneously, preferably synchronously, without a voltage intensity modulation of the side radiation source (103), a total radiation dose received by a patient during said vertical scan; and for the frontal image and the lateral image, local image contrasts of the identified specific bone localizations at different imaging positions along the vertical scanning direction. or, Both the drive current intensity modulation and the drive voltage intensity modulation of the front radiation source (101) are automatically performed simultaneously, preferably synchronously, and both the drive current intensity modulation and the drive voltage intensity modulation of the side radiation source (103) are automatically performed simultaneously, preferably synchronously, a total radiation dose received by a patient during said vertical scan; and for the frontal image and the lateral image, local image contrasts of the identified specific bone localizations at different imaging positions along the vertical scanning direction. A radiation imaging method that improves the compromise between:

4. The frontal multi-energy scout view is created by performing (1) a single preliminary vertical scan of a patient standing along the vertical scan direction with the frontal radiation source (101) and the frontal radiation detector (102), such that the frontal radiation detector (102) detects at least the first frontal scout view; Second Front Scout View And give The lateral multi-energy scout view is created by performing a single preliminary vertical scan of a patient standing along the vertical scan direction with the lateral radiation source (103) and the lateral radiation detector (104), such that the lateral radiation detector (104) detects at least: the first side scout view; 2nd side scout view And give 4. A method of radiological imaging according to claim 1, wherein both the frontal multi-energy scout view and the lateral multi-energy scout view are produced during the same single preliminary vertical scan.

5. the frontal image is produced by performing a single vertical scan of a patient standing along the vertical scan direction with the frontal radiation source (101) and the frontal radiation detector (102) (3); the lateral image is produced by performing (3) a single vertical scan of a patient standing along the vertical scan direction with the lateral radiation source (103) and the lateral radiation detector (104); A method of radiographic imaging according to claim 1 , wherein both the front and lateral images are produced during the same single vertical scan.

6. 6. A radiation imaging method according to any one of the preceding claims, wherein the first given energy threshold is less than or equal to the second given energy threshold, and preferably equal to the second given energy threshold.

7. the first given energy threshold is equal to the second given energy threshold; The frontal multi-energy scout view and / or the lateral multi-energy scout view are obtained by the frontal radiation detector and / or the lateral radiation detector (102, 104), 1. The first frontal scout view, a third frontal scout view, called a full-energy frontal scout view, corresponding to the total energy received by the frontal radiation detector (102); First, give the second frontal scout view is obtained by subtracting the first frontal scout view from the third frontal scout view; and / or the first side scout view; and / or a third side scout view, called a full-energy side scout view, corresponding to the total energy received by the side radiation detector (104). First, give The second side scout view is obtained by subtracting the first side scout view from the third side scout view. The radiation imaging method according to claim 6, wherein the imaging apparatus is produced as follows (1).

8. said first front and / or lateral scout view and said second front and / or lateral scout view are combined and processed to assess (22) a thickness profile of the patient's bone along said vertical scanning direction; and / or said first frontal and / or lateral scout view and said second frontal and / or lateral scout view are combined and processed to assess (22) a thickness profile of the patient's soft tissue along said vertical scanning direction; the frontal image is created by performing a vertical scan of a standing patient along the vertical scan direction by the frontal radiation source (101) and the frontal radiation detector (102); a modulation of the drive current intensity of at least the frontal radiation source (101) along the vertical scanning direction is dependent on a bone thickness profile of the patient and / or a soft tissue thickness profile of the patient along the vertical scanning direction; Preferably, said modulation of the driving voltage intensity of said frontal radiation source (101) along said vertical scanning direction also depends on a bone thickness profile of said patient and on a soft tissue thickness profile of said patient along said vertical scanning direction, the lateral image is produced by performing a vertical scan of a standing patient along the vertical scan direction with the lateral radiation source (103) and the lateral radiation detector (104); a modulation of the drive current intensity of at least the side radiation source (103) along the vertical scan direction is dependent on a bone thickness profile of the patient and / or a soft tissue thickness profile of the patient along the vertical scan direction; Preferably, said modulation of the drive voltage intensity of said side radiation source (103) along said vertical scanning direction also depends on a bone thickness profile of said patient and on a soft tissue thickness profile of said patient along said vertical scanning direction; A method of radiographic imaging according to claim 1 , wherein both the frontal and lateral images are produced during the same vertical scan.

9. the drive current intensity modulation of the front radiation source and / or the side radiation source (101, 103) is performed automatically without voltage intensity modulation of the front radiation source and / or the side radiation source (101, 103); reducing the overall radiation dose received by a patient during said vertical scan; For the frontal image and / or the lateral image, for all or a part of the thickness of the patient along the vertical scanning direction, the local image contrast of the identified specific bone localization at different imaging positions along the same vertical scanning direction is not reduced below a given contrast threshold. Try to improve the compromise between or both the driving current intensity modulation and the driving voltage intensity modulation of the front radiation source and / or the side radiation source (101, 103) are performed automatically, simultaneously, preferably synchronously, reducing the overall radiation dose received by a patient during said vertical scan; increasing a local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction for the frontal image and / or the lateral image, for all or a part of a patient thickness along the vertical scan direction, with the same total radiation dose, but without drive current intensity modulation or drive voltage intensity modulation; 9. A method for radiographic imaging according to any one of claims 1 to 8, which improves the compromise between:

10. the drive current intensity modulation of the front radiation source and / or the side radiation source (101, 103) is performed automatically without voltage intensity modulation of the front radiation source and / or the side radiation source (101, 103); reducing the overall radiation dose received by a patient during said vertical scan; Improving the contrast-to-noise ratio or the ratio between the contrast-to-noise ratio and the square root of the total radiation dose of the identified specific bone localization at different imaging positions along the vertical scan direction for the frontal image and / or the lateral image, for all or part of the patient thickness along the vertical scan direction, with the same total radiation dose but without drive current intensity modulation, for local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; Try to improve the compromise between or both the driving current intensity modulation and the driving voltage intensity modulation of the front radiation source and / or the side radiation source (101, 103) are performed automatically, simultaneously, preferably synchronously, reducing the overall radiation dose received by a patient during said vertical scan; Improving the contrast-to-noise ratio or the ratio between the contrast-to-noise ratio and the square root of the total radiation dose of the identified specific bone localization at different imaging positions along the vertical scan direction for the lateral image and / or the frontal image, for all or part of the patient thickness along the vertical scan direction, with the same total radiation dose but without drive current intensity modulation or drive voltage intensity modulation, for local image contrast of the identified specific bone localization at different imaging positions along the vertical scan direction; 10. A radiation imaging method according to claim 1 , which improves the compromise between:

11. The frontal multi-energy scout view acquisition includes at least two energy bins, or at least three energy bins, or at least six energy bins. and / or at most 20 energy bins, or at most 15 energy bins, or at most 10 energy bins This is carried out using (1), and / or the side multi-energy scout view acquisition includes at least two energy bins, or at least three energy bins, or at least six energy bins. and / or at most 20 energy bins, or at most 15 energy bins, or at most 10 energy bins The method of claim 1 , wherein the radiation imaging method is performed using (1)

12. the first and second front scout views are processed into a multi-material decomposition having at least two material thickness vertical profiles; Preferably, a bimaterial decomposition between AI and PMMA, or HA and H 2 It is processed into one of two materials decomposed between o, and / or the first and second side scout views are processed into a multi-material decomposition having at least two material thickness normal vectors; Preferably, a bimaterial decomposition between AI and PMMA, or HA and H 2 12. The method of claim 1, wherein the radiation imaging is processed into either a two-material decomposition between O and O.

13. For each of the radiation detectors (102, 104), the pixel size of the radiation detector is in the range of 50 μm to 250 μm, alternatively in the range of 80 μm to 150 μm, alternatively about 100 μm; and / or the overall height of the radiation detector is in the range of 0.1 cm to 1.2 cm, or in the range of 0.2 cm to 1.0 cm, or in the range of 0.3 cm to 0.7 cm; and / or the overall width of the radiation detector is in the range of 10 cm to 80 cm, or in the range of 20 cm to 70 cm, or in the range of 30 cm to 60 cm; 13. A radiation imaging method according to any one of claims 1 to 12, and / or wherein the radiation detector is operable in a time delay and sum mode.

14. 14. A radiological imaging method according to any one of claims 1 to 13, wherein the identified specific bone localization comprises, and preferably is, the patient's spine.

15. 15. The radiation imaging method according to claim 1, wherein both the drive current intensity modulation and the drive voltage intensity modulation of the front radiation source and / or the side radiation source (101, 103) are also performed to reach a signal-to-noise ratio value for the front image and / or the side image that is constant and common to a majority of the imaging positions along the vertical scanning direction, preferably to all the imaging positions along the vertical scanning direction, but which can take two different values ​​for the front image and the side image, respectively.

16. 16. A method according to claim 15, wherein for each of the frontal and / or lateral images the signal to noise ratio value is constant and pre-determined for each different patient organ being imaged.

17. for a frontal image of the patient's spine, said standard signal-to-noise ratio value corresponds to a number of X-ray photons received per detector pixel comprised between 50 and 70, the operator of the radiographic imaging method preferably having the possibility to deviate, via a manual command, by at least -25% or +100%, more preferably by at least -50% or +200%, and / or for a lateral image of the patient's spine, said standard signal-to-noise ratio value corresponds to a number of X-ray photons received per detector pixel comprised between 20 and 40, the operator of the radiographic imaging method preferably having the possibility to deviate, via a manual command, by at least -25% or +100%, more preferably by at least -50% or +200%, 17. A radiation imaging method according to claim 15 or 16.

18. 18. A radiation imaging method according to any one of claims 1 to 17, wherein the front and / or lateral images, after having undergone at least the local image contrast improvement, are normalised by homogenisation of the raw radiation in order to remove image artefacts arising from the drive current intensity modulation and the drive voltage intensity modulation, preferably the front and / or lateral images, after having been normalised, are subjected to a contrast enhancement step.

19. 19. The radiation imaging method according to any one of claims 1 to 18, wherein the localization of the identified specific bones excludes, if any, metallic prostheses of parts of the skeleton of the patient's body or metallic parts, such as, for example, metallic protective gear, which are worn on the patient's body before performing the radiation imaging method.

20. Modulation of both current and voltage intensity For larger patient thicknesses, both the current intensity and the voltage intensity are increased simultaneously; For smaller patient thicknesses, both the current intensity and the voltage intensity are simultaneously reduced; 20. A method according to claim 1, wherein the rate of variation of the current intensity is slower than the rate of variation of the voltage intensity.

21. 21. A method according to any preceding claim, wherein the current intensity modulation is maximized so as to also maximize the vertical scan velocity at a constant value.

22. 22. A method according to any one of the preceding claims, wherein the operating mode can be manually turned on or off by an operator of the method.

23. 23. The radiation imaging method according to any one of the preceding claims, wherein the operating mode is dedicated to vertical scanning of large and / or obese patients and / or the operating mode is dedicated to vertical scanning of pediatric patients.

24. 24. The radiation imaging method of claim 1, wherein the current intensity modulation rate does not exceed a predetermined threshold of 5 mA per millisecond, or does not exceed a predetermined threshold of 2 mA per millisecond, or does not exceed a predetermined threshold of 1 mA per millisecond.

25. 25. A radiation imaging method according to any one of the preceding claims, wherein the current intensity modulation is in the range of at least 20mA to 300mA, preferably in the range of 10mA to 400mA.

26. 26. A method according to any one of the preceding claims, wherein the voltage intensity modulation is in the range of at least 60 kV to 100 kV, preferably in the range of 50 kV to 130 kV.

27. 27. A method according to any preceding claim, wherein the vertical scan speed is in the range of at least 8 cm / sec to 20 cm / sec, preferably in the range of 0.4 cm / sec to 35 cm / sec.

28. 28. The radiation imaging method of claim 1, wherein each of the frontal scout views and / or lateral scout views is generated by performing a preparatory vertical scan of a patient standing along a vertical scan direction with a reduced overall radiation dose compared to each of the frontal and lateral images before generating each of the frontal and lateral images (1), preferably the reduced overall radiation being less than 10% of the overall radiation dose, more preferably less than 5% of the overall radiation dose.

29. 29. A method of radiological imaging according to any one of claims 1 to 28, wherein pixels in the scout view are collected by zones of NxN pixels, preferably ranging from 2x2 pixels to 10x10 pixels, to create an imaging zone.

30. 30. The method of claim 1, wherein the image or the imaging zone is processed to identify corner points (60), which are then used to calculate (22) the thickness profile and to identify (21) the localization of the particular bone of a patient standing along the vertical scan direction.

31. 31. The method of claim 1, wherein the image or the imaging zone is processed by a neural network to calculate (22) the thickness profile and to identify (21) the localization of the particular bone of a patient standing along the vertical scan direction.

32. 32. The radiation imaging method according to any one of claims 1 to 31, wherein the two radiation sources (101, 103) slide vertically to perform a vertical scan of the pelvis or spine or whole body of a standing patient along a vertical scanning direction.

33. 33. The radiation imaging method according to claim 1, wherein the two radiation detectors (102, 104) are associated with the two radiation sources (101, 103), respectively, and the two radiation detectors (102, 104) are two photon counting detectors (PCDs), each of which is associated with an automatic image processing function that automatically balances image grey levels whatever the amount of radiation received at the sensitive surface of the radiation detector (102, 104) in order to homogenize the response of the detector (102, 104).

34. 34. A radiation imaging method according to any one of claims 1 to 33, wherein the two radiation detectors (102, 104) are associated with the two radiation sources (101, 103), respectively, and the two radiation detectors (102, 104) are two multi-energy counting detectors, preferably two energy-resolving photon counting detectors (ERPCDs).

35. 35. The method of claim 1, wherein the radiation is X-rays.

36. 36. A radiation imaging method according to any one of claims 1 to 35, wherein the second energy threshold is selected to improve image contrast more for lower patient thickness regions along the vertical direction than for higher patient thickness regions along the vertical direction, preferably the second energy threshold is selected between 50 keV and 90 keV, preferably between 60 keV and 80 keV, more preferably the second energy threshold is selected at 70 keV.

37. 37. The radiation imaging method according to claim 1, wherein the first energy threshold and / or the second energy threshold are varied and / or associated spectral filtering, preferably k-edge filtering, is used and adjusted depending on the thickness of the patient's bone and / or the thickness of the patient's soft tissue and / or the localization of a particular bone of the patient at different imaging positions along the vertical scan direction.

38. (3) the front image and / or the lateral image are both monoenergetic images performed with the voltage intensity modulation of the front radiation source (101) and / or the lateral radiation source (103), 38. The radiation imaging method according to claim 1, wherein the front image and / or the lateral image are both multi-energy images performed without voltage intensity modulation of the front radiation source (101) and / or the lateral radiation source (103).

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