Apparatus and method for X-ray mammography using two X-ray sources

Abstract

The invention relates to an X-ray mammography apparatus (100, 200). According to the invention, the apparatus comprises a first source (10a) emitting a first X-ray flux (11a), a second source (10b) emitting a second X-ray flux (11b), an X-ray image detector (30) arranged in a first imaging configuration to capture the first X-ray flux (11a) transmitted through a portion of the breast and, respectively, in a second imaging configuration to capture the second transmitted X-ray flux (11b), said apparatus (100, 200) having in the second imaging configuration an optical magnification greater than or equal to 8 and less than 20, and a processing unit (40) configured to determine a mammographic image by absorption from the first imaging configuration and to reconstruct, from the second imaging configuration, a phase-contrast image. Figure for the abstract: Fig. 1

Description

Title of the invention: Apparatus and method for X-ray mammography using two X-ray sources Technical field of the invention

[0001] The present invention relates generally to an apparatus and a method of X-ray mammography.

[0002] More specifically, the invention relates to an apparatus and a method of X-ray mammography for the characterization of breast microcalcifications in-vivo. State of the art

[0003] Breast cancer is currently the most common cancer among women and also the leading cause of cancer death in women (685,000 deaths worldwide in 2020), ahead of lung and colorectal cancers. It accounts for one in four cancers diagnosed in women. In 2020, 2.3 million new cases were diagnosed worldwide.

[0004] Breast microcalcifications are calcium deposits in breast tissue and appear as small, bright spots on conventional mammogram images. Microcalcifications play a crucial role in breast cancer screening, particularly for non-palpable breast cancers, and are present in approximately one-third of all malignant lesions detected during screening mammography. Microcalcifications are more common in ductal carcinoma in situ than in invasive breast cancers.

[0005] X-ray absorption imaging consists of measuring the differences in opacity of an object to X-rays, induced by its inhomogeneity in terms of materials or density. The X-ray absorption imaging technique is appropriate when the objects studied are made of materials exhibiting sufficient differences in absorption.

[0006] X-ray mammography devices are known. These devices are functional because they allow mammographic images to be obtained by absorption of patients' breasts. However, if objects are detected, for example microcalcifications, it is necessary to take a sample from the patient's breast, which is invasive and painful, and to analyze this sample on a second X-ray imaging device to observe the detected object more precisely.

[0007] Following the taking of a macrobiopsy, the practitioner can use the second specimen radiography unit to radiograph this sample. These second imaging units are functional because they allow for obtaining absorption images of the sample taken. However, such images exhibit low contrast and poor spatial resolution, thus limiting their use. Furthermore, the use of such images can lead to errors caused by their low contrast and resolution. Currently, commercially available specimen radiography systems are based on the absorption X-ray imaging technique and provide images with low spatial resolution. Consequently, in this case, at least two X-ray imaging devices are required, which creates problems related to cost, space, and analysis and implementation time, as sample analysis and imaging are often performed at a different location than the absorption mammography imaging.

[0008] The analysis of microcalcifications to distinguish their types is very useful for discerning the characteristics of breast lesions and thus improving the early diagnosis of breast cancer.

[0009] To date, the analysis of microcalcifications is primarily performed in pathology departments on tissue samples obtained during macrobiopsies of the patient's breast. Pathologists thus perform pathological studies by optical microscopy on samples prepared from the macrobiopsies. These optical microscopy analyses require sample preparation that is time-consuming, costly, and delays obtaining results. Furthermore, the detection of a suspicious area necessarily involves a macrobiopsy, which is tedious and uncomfortable for the patient.

[0010] It is desirable to propose a device and a method allowing the in vivo detection and analysis of microcalcifications in order to allow them to be distinguished and classified into different types, quickly, efficiently and without pain for the patient. Presentation of the invention

[0011] In order to overcome the aforementioned drawbacks of the prior art, the present invention proposes an X-ray mammography apparatus using two X-ray sources, said apparatus comprising at least: - a breast platform and a compression tablet arranged to position and immobilize part of a patient's breast; - a first mobile X-ray source arranged in a first imaging configuration to emit, from an emission spot having a diameter greater than or equal to 50 micrometers (pm), preferably between 50 pm and 2 mm, a first X-ray flux towards a part of the patient's breast, the part of the breast being immobilized between the platform and the compression tablet, - a second mobile X-ray source arranged in a second imaging configuration to emit, from an emission spot with a diameter between 1 pm and 20 pm, a second X-ray flux, the second X-ray flux being directed towards a portion of the immobilized part of the patient's breast, - an X-ray image detector arranged in the first imaging configuration to capture the first X-ray flux transmitted through the breast portion and, respectively, in the second imaging configuration to capture the second X-ray flux transmitted through the portion of the breast, - the platform and the compression tablet being located between the X-ray image detector and the first X-ray source in the first imaging configuration or, respectively, between the X-ray image detector and the second X-ray source in the second imaging configuration, - a source support on which the first X-ray source and the second X-ray source are mounted, said source support being arranged to alternately position the first X-ray source in the first imaging configuration and the second X-ray source in the second imaging configuration, - a control unit configured to activate or deactivate at least the first X-ray source in the first imaging configuration or the second X-ray source in the second imaging configuration, said activation of the first or second X-ray source being carried out alternately (or asynchronously), said device having in the second imaging configuration a distance between the second X-ray source and the X-ray image detector of between 80 cm and 1.6 m and an optical magnification greater than or equal to 8 and less than 20 and - a processing unit configured to determine an absorption mammographic image of the patient's breast portion from the first X-ray stream captured by the X-ray image detector in the first imaging configuration and to reconstruct, from the second X-ray stream captured by the X-ray image detector in the second imaging configuration, a phase-contrast image of the patient's breast portion.

[0012] Thanks to the arrangement of the device according to the present disclosure, it is possible to obtain two distinct imaging configurations which make it possible to determine with the same device and the same X-ray image detector, a mammographic image by absorption of a part of the breast and a phase contrast image of a portion of the part of the patient's breast previously imaged, with a higher optical magnification than the mammographic image by absorption.

[0013] As a result, with such a device, gains in volume, implementation cost and analysis time are achieved compared to state-of-the-art techniques and devices that require at least two separate imaging devices.

[0014] In addition, thanks to such a device, it is no longer necessary to perform macrobiopsy of the patient's breast for benign cases, which simplifies the acquisition of the image by phase contrast and improves its implementation time while improving the patient's comfort.

[0015] Next, the arrangement of the two X-ray sources on the source support, the compression tablet, the breast support and the X-ray image detector makes it possible to obtain in the second imaging configuration, a high optical magnification, which makes it possible to capture a particular phase shift on the imaging detector and to analyze this phase shift in order to be able to use phase contrast imaging.

[0016] The use of phase contrast imaging makes it possible to reconstruct images of the portion of the breast imaged in the second configuration with high contrast and high spatial resolution in 2D.

[0017] Other advantageous and non-limiting features of the apparatus according to the invention, taken individually or according to all technically possible combinations, are as follows.

[0018] According to a particular and advantageous aspect, the device has in the first imaging configuration a distance between the first X-ray source and the detector of between 50 cm and 120 cm and an optical magnification greater than or equal to 1 and less than or equal to 2.

[0019] According to another particular and advantageous aspect, in the second imaging configuration, the second X-ray stream transmitted through the compression tablet and platform propagates in a free field towards the X-ray image detector.

[0020] In one embodiment, the source support comprises a rail in which the control unit is configured to move at least the first source and the second source along the rail of the source support so as to position: i) either the first X-ray source in the first imaging configuration, ii) or the second X-ray source in the second imaging configuration.

[0021] Advantageously, in the first imaging configuration, the X-ray image detector is positioned opposite the first X-ray source, and in the second imaging configuration, the X-ray image detector is positioned opposite the second X-ray source.

[0022] Advantageously, in the first imaging configuration, the first X-ray source is arranged so as to emit the first X-ray flux in an emission cone around a vertically oriented propagation axis directed towards the ground, and wherein, in the second imaging configuration, the second source of X-rays are arranged so as to emit the second X-ray flux in an emission cone around a propagation axis oriented vertically and directed towards the ground.

[0023] Advantageously, the X-ray image detector comprises a pixel matrix having a first spatial dimension and a second spatial dimension, the first spatial dimension being greater than or equal to 10 cm and the second spatial dimension being greater than or equal to 10 cm.

[0024] Advantageously, the processing unit is configured to determine, by using an edge detection algorithm on said phase contrast image, the presence of an object in said phase contrast image and a morphology of each detected object.

[0025] In one embodiment, the apparatus comprises at least one of the following elements: a support on which are mounted at least the source support, the breast platform and the compression tablet, the X-ray image detector, a housing associated with the support, the housing housing at least the source support, the first X-ray source and the second X-ray source, the breast platform and the compression tablet, the X-ray image detector, a device for holding the support to the ground.

[0026] According to a particular and advantageous aspect, the apparatus includes a detector adjustment device configured to move the detector along at least one spatial direction so as to adjust the distance between the detector and the first X-ray source in the first imaging configuration or so as to adjust the distance between the detector and the second X-ray source in the second imaging configuration, and / or the adjustment device being adapted to adjust an orientation of the detector along at least one rotation.

[0027] According to a particular and advantageous aspect, the device includes a position adjustment device for the breast platform and the compression tablet, the position adjustment device being adapted to adjust a position of the breast platform and the compression tablet relative to the first X-ray source in the first imaging configuration or relative to the second X-ray source in the second imaging configuration.

[0028] According to another particular and advantageous aspect, the apparatus includes another device for adjusting the position and / or orientation of the source support to adjust a position of said source support relative to the X-ray image detector along at least one spatial direction, said at least one spatial direction corresponding to a translation of said source support relative to the X-ray image detector and / or to adjust the orientation of the source support relative to the X-ray image detector along at least one angle of rotation.

[0029] Advantageously, in the first imaging configuration, the control unit is configured to move the first X-ray source to different positions along the source support (62) and, for each position, determine a mammographic image by absorption and a phase contrast image.

[0030] In an application, said device is configured to reconstruct: a mammographic image by absorption of a portion of the patient's breast by tomosynthesis from at least three absorption images of said portion of the patient's breast, the three absorption images being taken in three distinct orientations and / or a phase contrast image by tomosynthesis of the portion of the patient's breast from at least three phase contrast images of said portion of the patient's breast, the three phase contrast images being taken in three distinct orientations.

[0031] The invention also proposes a method of X-ray mammography comprising the following steps: - arrangement of a device according to this disclosure in a first imaging configuration, the first X-ray source, the breast platform, the compression shelf, the wedge and the detector being arranged according to the first imaging configuration, a portion of a patient's breast 1 being immobilized between the platform and the compression shelf; - emission of a first X-ray flux from the emission spot of the first free-field X-ray source towards the part of the patient's breast immobilized between the platform and the compression tablet, the emission spot of the first X-ray source having a diameter greater than or equal to 50 pm; - detection of a first intensity X-ray image via the detector to obtain a first absorption image of a part of the patient's breast 1; - arrangement of the same apparatus in a second imaging configuration, the second X-ray source, the breast platform, the compression tablet, the wedge and the detector being arranged according to the first imaging configuration, the part of a patient's breast being immobilized between the platform and the compression tablet, said apparatus having in the second imaging configuration a distance between the second X-ray source and the X-ray image detector of between 80 cm and 1.6 m and an optical magnification greater than or equal to 8 and less than 20; - emission of a second X-ray beam from the emission spot of the second free-field X-ray source towards a portion of the patient's breast immobilized between the platform and the compression tablet, the emission spot of the second X-ray source having a diameter between 1 pm and 20 pm; - detection of a second intensity X-ray image via the detector; - processing of the second image to determine a phase shift image and reconstruct, from this phase shift image, a phase contrast image of the portion of the patient's breast.

[0032] Of course, the various features, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0033] The following description with regard to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be carried out.

[0034] On the attached drawings:

[0035] [Fig-1] is a schematic representation in profile view of a device according to a first embodiment used in a first imaging configuration;

[0036] [Fig.2] is a schematic front view representation of the device of the first embodiment used in the first imaging configuration;

[0037] [Fig.3] is a zoomed schematic front view representation of a source support used in the device according to the first embodiment used in the first imaging configuration;

[0038] [Fig.4] is a schematic cross-sectional view representation of a first X-ray intensity image obtained by a processing unit of the device according to the first embodiment used in the first imaging configuration;

[0039] [Fig.5] illustrates a mammographic image by X-ray absorption obtained with the device according to the first embodiment used in the first imaging configuration;

[0040] [Fig.6] is a schematic representation in profile view of the device according to the first embodiment used in a second imaging configuration;

[0041] [Fig.7] is a schematic front view representation of the device according to the first embodiment used in the second imaging configuration;

[0042] [Fig.8] is a zoomed schematic front view representation of the source support of the device according to the first embodiment in the second imaging configuration

[0043] [Fig.9] is a schematic representation of a second image of a phase shift determined by a processing unit of the device according to the first embodiment used in the second imaging configuration;

[0044] [Fig. 10] illustrates a series of absorption images (10A, 10B, 10C) of different spots visible on the absorption images obtained with the device according to the first embodiment in the first imaging configuration and a series of phase contrast images (10D, 10E, 10F) of the same spots reconstructed from the second imaging configuration;

[0045] [Fig. 11] is a schematic representation in profile view of a device according to a second embodiment used in the first imaging configuration;

[0046] [Fig. 12] is a schematic front view representation of the device according to the second embodiment used in the first imaging configuration;

[0047] [Fig. 13] is a schematic representation in profile view of a device according to a second embodiment used in the second imaging configuration;

[0048] [Fig. 14] is a schematic front view representation of the device according to the second embodiment used in the second imaging configuration;

[0049] [Fig. 15] is a schematic representation of a method according to the present invention.

[0050] Device

[0051] A first embodiment of an X-ray mammography apparatus using two X-ray sources will now be described with the aid of Figures 1 to 10.

[0052] As described in this disclosure, the device 100 has two imaging configurations, a first imaging configuration using a first X-ray source 10a to determine an absorption mammographic image of a portion of a breast 1 of a patient, hereinafter referred to as the patient, and a second imaging configuration using a second X-ray source 10b to reconstruct a phase-contrast image of a portion of the breast 1 of the patient.

[0053] For this purpose, the device 100 includes the first X-ray source 10a, the second X-ray source 10b, a platform 20 for supporting the breast being examined, as well as a compression tablet 22, an X-ray image detector 30, a processing unit 40, a control unit 51 and a source support 62.

[0054] As explained in detail below, the first X-ray source 10a and the second X-ray source 10b are used alternately, in particular here the first source is used in the first imaging configuration and the second source is used in the second imaging configuration.

[0055] The first imaging configuration of the device 100 and an example of a mammography image obtained in this first imaging configuration will now be described using Figures 1 to 5.

[0056] As illustrated in figures 1 to 3, in the first imaging configuration, the first X-ray source 10a is arranged to emit from an emission spot a first flux 1 la of X-rays towards the breast 1 of the patient.

[0057] Typically, the emission spot of the first X-ray source 10a has a diameter Da greater than or equal to 50 pm, preferably between 50 pm and 2 mm. The diameter Da of the emission spot is the minimum diameter of the first X-ray flux 1 la also called the focusing diameter of the first X-ray source 10a.

[0058] In the first imaging configuration, the compression tablet 22 is spaced from the first X-ray source 10a by a distance dla between 20 cm and 1 m, preferably between 50 cm and 1 m in order to set a magnification value of the device 100 in the first imaging configuration which will be explained below. This distance dla is determined between a plane Pla of the emission spot of the first 10a of X-rays, here oriented perpendicular to the propagation axis Aa of the first 10a of X-rays (or perpendicular to the z-axis) and a plane P2a of the compression tablet 22 oriented parallel to the emission plane Pla of the first 10a of X-rays and perpendicular to the propagation axis Aa of the first 10a of X-rays.Here, the plane of the second main surface 25 of the compression tablet 22 coincides with this plane P2a.

[0059] In the first imaging configuration, the X-ray image detector 30 is positioned at a distance d2a from the first X-ray source 10a of between 50 cm and 120 cm, preferably between 60 cm and 80 cm from the first X-ray source 10a. This distance d2a is determined between the emission plane Pla of the first X-ray source 10a and a plane P3 of the X-ray image detector 30 oriented parallel to the plane Pla of the emission spot of the first X-ray source 10a and perpendicular to the propagation axis Aa of the first X-ray flux 1la. Here, the plane P3 is contained within an active surface 31 of the X-ray image detector 30 which is described below.

[0060] The distance dla first source 10a - compression tablet 22 and the distance d2a first source 10a - image detector 30 of X-rays allow us to define a first optical magnification of the device 100 as being the ratio between the distance dla (distance separating the first source 10a of X-rays from the compression tablet 22) and the distance d2a (distance separating the first source 10a of X-rays from the image detector 30 of X-rays).

[0061] Here in particular, in this configuration, the first optical magnification of the device 100 is greater than or equal to 1 and less than or equal to 2. Preferably, the first optical magnification of the device 100 is between 1 and 2 in order to obtain better resolution on the absorption mammographic image of the patient's breast 1 with the device 100 in the first configuration.

[0062] As illustrated in [Fig. 1], the first X-ray flux 1 la emitted by the first X-ray source 10a has a propagation axis Aa oriented vertically and directed towards the ground. In other words, the propagation axis Aa is parallel to the z-axis of the orthonormal coordinate system shown in [Fig. 1] and defined by the x, y, and z axes. Such a configuration helps to minimize X-ray reflections on other elements outside the device 100.

[0063] The first X-ray source 10a is a conventional X-ray mammography source, for example, a source based on a rotating anode mammography tube. It has a spot diameter Da (at the output of the first source 10a) greater than or equal to 50 pm. The first X-ray source 10a generates, for example, an X-ray emission spectrum between 20 keV and 70 keV, by applying a high voltage between 20 kV and 70 kV, with a current intensity greater than 30 mA and a power greater than 1 kW.

[0064] In the first imaging configuration, the first X-ray flux 1 la, exiting the first X-ray source 10a, has a power greater than or equal to 1 kW. Generally, the first X-ray source 10a emits the first X-ray flux 1 la within an emission cone specific to that source lia. Here, by emission cone, we mean a cone of revolution about a propagation axis Aa, having as its generatrix the diameter Da of the emission spot and having an apex angle or aperture angle at the exit of the first X-ray source 10a. The emission cone represents the volume in which the first X-ray flux 1 la propagates from the emission spot of the first X-ray source 10a towards the part of the patient's breast that is immobilized between the platform 20 and the compression tablet 22.In other words, the first X-ray flux 1 la exiting the first X-ray source 10a is divergent, and propagates along the emission cone of the first X-ray source 10a to the compression tablet 22.

[0065] In a known manner, the platform 20 and the compression tablet 22 are each mounted to move in translation along the z-axis, in order to adjust the position of the platform 20 to the size of the patient and to adjust the position of the compression tablet 22 to the size of the breast 1 being examined.

[0066] Preferably, the opening angle of the emission cone of the first X-ray source 10a, which is the total angle, is between 10 degrees and 45 degrees.

[0067] The first X-ray flux 1la has a wavelength between 0.018 nm and 0.062 nm. It propagates in free space from the first X-ray source 10a to the compression plate 22 of the device 100. Here, "free space" means propagation in free space. In other words, the first X-ray flux 1la does not encounter any other element of the device 100 before reaching the compression plate 22.

[0068] It is noted that the first flux 1 la of X-rays presents a first initial wavefront representing its propagation at the exit of the first source 10a of X-rays.

[0069] This first flow 1 of X-rays propagates towards the breast 1 of the patient.

[0070] As schematically illustrated in Figures 1 and 2, the patient's breast 1 is held in place by the breast platform 20 which supports the patient's breast 1. This breast platform 20 is in this example in the form of a flat plate with a main face 21 oriented parallel to the xy plane, i.e. horizontally.

[0071] As schematically illustrated in [Fig. 1], the breast support 20 is associated with the compression plate 22 arranged to compress the patient's breast 1 on the breast platform 20, specifically to compress the patient's breast 1 against the first main face 21 of the breast platform 20. Similarly, the compression plate 22 is in the form of a flat plate facing the main face 21 of the breast platform 20 and oriented parallel to this main face 21 of the breast platform 20. The compression plate 22 comprises a first main face 23 oriented opposite the first main face 21 of the breast platform 20 and a second main face 25 oriented opposite the output of the first X-ray source 10a.It is understood that this compression tablet 22 is mobile along at least one spatial direction, corresponding here to a translation of the compression tablet 22 along the z-axis, moving away from or towards the breast platform 20, in order to compress the patient's breast 1 so as to reduce its thickness as much as possible and thus improve the resolution of the mammographic image by absorption. Of course, it is also possible that both the compression tablet 22 and the breast support 20 are mobile, particularly along the z-axis, to compress the patient's breast 1 during the radiological examination and then release it at the end of the examination.

[0072] As schematically illustrated in [Fig. 1] and [Fig. 2], a part of the breast One tablet of the patient is entirely positioned within the emission cone of the first X-ray source. In other words, this part of the breast is completely irradiated by the first X-ray beam. Thus, in this configuration, the entire portion of the patient's breast is irradiated by the first X-ray beam; this portion is also referred to as the portion of the breast irradiated by the first X-ray beam.

[0073] Here, in this example, the first X-ray source 10a is configured to irradiate breast 1 for a time period of between 10 milliseconds and 35 seconds in order to have enough signal to determine the absorption mammographic image which will be described below.

[0074] For example, part of the breast 1 is irradiated for 10 seconds in order to have a good compromise between the dose of X-rays received by the patient and the amount of signal acquired to obtain the mammographic image by absorption of the patient's breast.

[0075] The first X-ray source 10a is configured to continuously irradiate breast 1 at a dose between 0.5 mSv and 2.5 mSv. This range makes it possible to limit the X-ray dose received by the patient in accordance with health and safety standards while providing sufficient signal to allow rapid acquisition of the mammographic image by absorption of the portion of the patient's breast 1. For example, the X-ray dose received by exposure to the first X-ray beam 1 is 1 mSv.

[0076] Thus, the first X-ray flux 1 la propagates in a free field from the first X-ray source 10a to the compression tablet and passes through the compression tablet 22, part of the breast 1, and the breast platform 20. For this purpose, it is understood that the compression tablet 22 and the breast platform 20 are weakly absorbent in the wavelength range emitted by the first X-ray source 10a. Here, weakly absorbent means that the compression tablet 22 and the breast platform 20 are arranged and / or configured to transmit between 50% and 95% of the first X-ray flux 1 la.

[0077] After passing through the compression tablet 22, the immobilized breast portion 1, and the breast platform 20, the first X-ray flow 1 reaches the X-ray image detector 30, which, in the first imaging configuration, is positioned opposite the first X-ray source 10a. It is thus understood that, in the first imaging configuration, the compression tablet 22 and the breast platform 20 are positioned between the first X-ray source 10a and the X-ray image detector 30.

[0078] In this first embodiment, no optical element (other than the compression tablet 22 and the breast platform 20) is positioned on the optical path of the first lia flow passing through the breast.

[0079] In this first imaging configuration, the X-ray image detector 30 is arranged to capture the first X-ray flux 1 la passing through breast 1. It is understood that the first X-ray flux 1 la captured by the X-ray image detector 30 has a wavefront, hereafter referred to as the first transmitted wavefront, which represents a spatial distribution of the first X-ray flux 1 la passing through breast 1, the compression tablet 22 and the breast platform 20. The X-ray image detector 30 operates by direct or indirect detection.

[0080] For example, the X-ray image detector 30 operates by indirect detection, using a flat screen comprising an array of cesium iodide (Csl) crystals combined with an array of CMOS (complementary metal oxide semiconductor) detectors. The X-ray image detector 30 thus comprises a pixel array, each pixel having a side length less than or equal to 100 pm.

[0081] Typically, in the apparatus 100, the X-ray image detector 30 has a size adapted to the first X-ray source 10a and the second X-ray source 10b used, in particular to the emission cone of the X-ray source used. In other words, the X-ray image detector 30 is arranged to capture the first total X-ray flux 11a (in the first imaging configuration) and the second total X-ray flux 11b (in the second imaging configuration).

[0082] The X-ray image detector 30 has an active face 31, oriented towards the X-ray source used (the first X-ray source 10a in the first imaging configuration and, respectively, the second X-ray source 10b in the second imaging configuration) and comprising a pixel array 32 in which each pixel is configured to capture a portion of the X-ray flux emitted in the imaging configuration used. The X-ray image detector 30 thus records an intensity image of the X-ray flux that has passed through the patient's breast, the compression tablet 22, and the breast platform 20.

[0083] This pixel matrix 32 has a first spatial dimension oriented parallel to a spatial axis (x-axis), and a second spatial dimension perpendicular to the first spatial dimension and oriented parallel to the y-axis. Advantageously, the pixels of the pixel matrix 32 are arranged in rows and columns.

[0084] Advantageously, the X-ray image detector 30 is a flat panel detector with a detection area of ​​at least 10 cm x 10 cm. The X-ray image detector 30 has an active face 31, oriented towards the X-ray source 10 and comprising a pixel matrix 32 in which each pixel is configured to capture a portion of the X-ray flux 11 passing through the sample 1. The image detector 30 thus records an intensity image of the X-ray flux that has passed through the sample 1.

[0085] This pixel matrix 32 has a first spatial dimension oriented parallel to a spatial axis, for example the x-axis, and a second spatial dimension perpendicular to the first spatial dimension and oriented parallel to the y-axis. Advantageously, the pixels of the pixel matrix 32 are arranged in rows and columns.

[0086] Without limitation, the first and second spatial dimensions are each greater than 10 cm; in particular, here the first spatial dimension is 22.8 cm and the second spatial dimension is 29.2 cm. Advantageously, the first and second spatial dimensions are each less than 40 cm, in order to limit the overall size of the device 100.

[0087] Thus, in this example, the pixel matrix 32 of the X-ray image detector 30 is rectangular in shape. Of course, the image detector 30 can, in a alternative, present other shapes, for example a square shape when the first spatial dimension and the second spatial dimension are the same size.

[0088] The pixels of the pixel matrix 32 are all identical and each has a first dimension, oriented parallel to the first spatial dimension of the pixel matrix 32, and a second dimension, perpendicular to the first dimension and oriented parallel to the second spatial dimension of the pixel matrix. The first and second dimensions are each less than or equal to 100 pm and preferably between 40 pm and 60 pm. Here, typically, the pixel matrix 32 is made of square pixels with sides of 49.5 pm. The pixel matrix 32 of the X-ray image detector 30 has a number of pixels ranging from 4000 to 6000 in each direction, for example, 4600 pixels in one direction and 5800 pixels in the other direction.

[0089] Thus, in this example, the pixel matrix 32 of the X-ray image detector 30 is rectangular in shape. Of course, the latter can, in a variant, have other shapes, for example a square shape when the first spatial dimension and the second spatial dimension are the same size.

[0090] The present dimensions of the image detector 30 (size range and pixel size range) and the high number of pixels make it possible to obtain a high spatial resolution absorption mammographic image in the first imaging configuration and a high spatial resolution phase contrast image in the second imaging configuration.

[0091] The first X-ray flux 1, having been captured by the X-ray image detector 30, is then analyzed by the processing unit 40 of the device 100.

[0092] A processing unit is defined as any computing unit, processor, computer, or other electronic element that enables the execution of a series of commands and / or calculations. This processing unit 40 typically comprises a processor, memory, and various input and output interfaces.

[0093] Thanks to its input and output interfaces, the processing unit 40 is programmed to receive any data measured by the X-ray image detector 30.

[0094] Thanks to its memory, the processing unit 40 stores a computer application, consisting of computer programs including instructions whose execution by the processor makes it possible to reconstruct the mammographic image by absorption in the first imaging configuration and the phase contrast image of the part of the patient's breast 1 in the second imaging configuration.

[0095] The processing unit 40 of the device 100 is at least connected to the X-ray image detector 30 described above. By connected, it is meant that the processing unit 40 is arranged to communicate with another element, for example, by being configured to transmit and / or receive data from this element (here for example via wired connection).

[0096] Here, in this case, in the first imaging configuration, the processing unit 40 is configured to determine a mammographic image by absorption from the first X-ray stream 1 captured by the X-ray image detector 30.

[0097] In practice, the first X-ray flow 1 la corresponds to an intensity signal which is analyzed by the processing unit 51 to determine a first intensity image of the first X-ray flow 1 la transmitted through the immobilized part of the patient's breast.

[0098] Indeed, the spatial distribution of the transmitted intensity of the first X-ray flux 1 la and captured by the X-ray image detector 30 corresponds to an absorption signal of the first X-ray flux 1 la which was modified during its passage through the breast 1 of the patient.

[0099] To this end, [Fig. 4] schematically illustrates a cross-sectional view of the breast 1 determined by the processing unit 40 from the first X-ray flux 1 captured by the X-ray image detector 30 in the first imaging configuration. More precisely, [Fig. 4] represents an intensity profile of the X-rays captured on the image detector 30 in the first imaging configuration by a plurality of pixel lines extending, for example, along the x-axis.

[0100] This first intensity image has a convex shape. In other words, the intensity signal has a main part PSa in which the intensity signal follows a bell curve variation and two secondary parts PSb, framing the main part, in which the intensity signal is (approximately) constant.

[0101] In the first imaging configuration, the X-ray image detector 30 is configured to detect the transmitted intensity and directly obtain an inverted image of the absorption by the portion of the breast irradiated by the X-ray flux 1 in a manner known to those skilled in the art. The publication Dance, DR, Lemoigne, Y., Caner, A., & Rahal, G. (2007). Physical principles of mammography. Physics for Medical Imaging Applications, 240, 355, describes, for example, the X-ray absorption mammography imaging technique. Indeed, a high-intensity signal in one pixel area corresponds to low absorption in the region of the breast opposite that pixel area. Conversely, a low-intensity signal in another pixel area corresponds to high absorption in another region of the breast opposite that other pixel area.

[0102] The detected intensity thus directly provides a mammographic image by absorption of the breast.

[0103] Figure 5 illustrates an absorption mammographic image of a portion of the breast determined by the device 100 in the first imaging configuration. As one As can be seen, the image obtained by the first imaging setup exhibits high contrast and good resolution. The dark background corresponds to regions of low absorption in the X-ray flux. The filaments and bright spots correspond to regions of higher absorption in the X-ray flux.

[0104] The processing unit 40 can also be configured to analyze the absorption mammographic image of the breast and detect objects in that image. The objects thus detected are characterized, for example, by at least one of the following: position, size, shape, intensity of the object, etc. Here, in [Fig. 5], an Oba object is detected and sorted according to its intensity and shape. In particular, bright spots may indicate the presence of microcalcifications. For this purpose, the processing unit 40 can be used to detect microcalcifications present in the absorption mammographic image of the breast acquired by the device 100 in the first imaging configuration.

[0105] To switch from the first imaging configuration to the second imaging configuration, the device 100 uses the control unit 51. The latter is arranged to control the various elements of the device 100, here at least the first X-ray source 10a, the second X-ray source 10b. It is also configured to control the other elements of the device 100, such as at least the X-ray image detector 30 and the processing unit 40.

[0106] As described above, in the first imaging configuration, only the first X-ray source 10a emits an X-ray flux, corresponding here to the first X-ray flux lia.

[0107] For this purpose, the device 100 uses the control unit 51 which is configured to activate and deactivate at least the first X-ray source and the second X-ray source, this activation of the first X-ray source and the second X-ray source being carried out asynchronously and sequentially.

[0108] By asynchronous and sequential, it is understood that the activation is carried out alternately. In other words, in the first imaging configuration, the control unit 51 is configured to activate the first X-ray source 10a and to turn off or keep the second X-ray source 10b on standby, whereas in the second imaging configuration, the control unit 51 is configured to activate the second X-ray source 10b and to turn off or keep the first X-ray source 10a on standby.

[0109] It is therefore understood that in the first imaging configuration, the second X-ray source does not emit any X-ray flux.

[0110] By control unit 51, we mean any computing unit or processor or computer or any other electronic element enabling the implementation of a sequence of commands and / or calculations. This control unit 51 typically comprises a processor, memory and various input and output interfaces. Typically, the control unit 51 may include a microcontroller.

[0111] Thanks to its input and output interfaces, the control unit 51 is programmed to receive any data measured by the detector of the device 100 and / or any data analyzed by the processing unit 40. By way of non-limitation, the device 100 includes a screen 53 connected to the control unit 51. The control unit 51 is also programmed to control the screen 53 and more generally any Human-Machine Interface enabling the communication of information to a user of the device 100. This screen 53 may or may not be touch-sensitive.

[0112] In practice the processing unit 40 and the control unit 51 can be two separate calculation modules or a single calculation module, or be a single element performing the functions of the processing unit 40 and the control unit 51.

[0113] In the device 100, the control unit 51 is also configured to move at least the first source 10a and the second source 10b along the source support 62 so as to alternately position: i) the first X-ray source 10a in the first imaging configuration, and ii) the second X-ray source 10b in the second imaging configuration.

[0114] As explained above, in the first imaging configuration, the first X-ray source 10a, the compression tablet 22, the breast platform 20 and the image detector 30 are aligned along the emission axis Aa of the first X-ray source 10a.

[0115] To switch between the two imaging configurations, the first X-ray source 10a and the second X-ray source 10b are mounted on the source support 62. Here for example, as illustrated in figures 2 and 3, the source support 62 is in the form of an arched rail on which the first X-ray source 10a and the second X-ray source 10b are mounted.

[0116] This source support 62 has a curved shape, specifically in the form of a circular arc, and is arranged to extend in a plane parallel to the xz plane with a portion of the circular arc transverse to the translation axis (z-axis) along which the propagation axis Aa of the first X-ray source 10a is aligned. Advantageously, a first motorized actuator allows the first X-ray source 10a to be moved along the circular arc of the source support 62. Similarly, a second motorized actuator allows the second X-ray source 10b to be moved along the circular arc of the source support 62.

[0117] Such a shape thus makes it possible to move the first X-ray source 10a and the second X-ray source 10b simply and inexpensively in order to switch from the first imaging configuration to the second imaging configuration and conversely from the second imaging configuration to the first imaging configuration.

[0118] Alternatively, the shaped support includes other types of actuators, for example, translational actuators along the x-axis and / or the y-axis. The rail of the source support 62 can also be linear.

[0119] Thus, it is understood that in the first imaging configuration, the first X-ray source 10a is oriented towards the X-ray image detector 30. Consequently, in this configuration, the emission cone of the X-ray flux 1la emitted by the first X-ray source 10a is contained within the optical field (or capture zone) of the X-ray image detector 30, whereas, conversely, in this first imaging configuration, the second X-ray source 10b is positioned outside the optical field of the X-ray image detector 30. Moreover, in the first imaging configuration, the second X-ray source 10b is inactive when the first X-ray source 10a is activated.

[0120] Similarly, it is understood that in the second imaging configuration, described below, the emission cone of the X-ray flux 11b emitted by the second X-ray source 10b is contained within the optical field (or capture zone) of the X-ray image detector 30, whereas, conversely, in this second imaging configuration, the first X-ray source 10b is positioned outside the optical field of the X-ray image detector 30. Moreover, in the second imaging configuration, the first source 10a is inactive when the second X-ray source 10b is activated.

[0121] Thus, to switch from the first imaging configuration to the second imaging configuration, the control unit 51 is configured to disable (i.e., turn off or put into standby mode) the first X-ray source 10a and the second X-ray source 10b and move the first X-ray source 10a and the second X-ray source 10b so that the second X-ray source 10b is positioned opposite the X-ray image detector 30.

[0122] The second imaging configuration of device 100 will now be described using Figures 6 to 8.

[0123] After positioning the second 10b X-ray source, the control unit is configured to activate the second 10b X-ray source and maintain the deactivated state of the first 10a X-ray source.

[0124] Similarly, the second X-ray source 10b is arranged to emit from an emission spot (or bright spot) a second X-ray flux 11b towards the patient's breast 1.

[0125] The emission spot of the second X-ray source 10b has a diameter Db between 1 pm and 20 pm. The diameter Db of the emission spot is the diameter The minimum diameter of the second 11b X-ray flux is also called the focal diameter of the second 10b X-ray source. The focal spot diameter Db is the minimum diameter of the second 11b X-ray flux. In other words, the second 10b source is a microfocus source. Specifically, using the second X-ray flux with this diameter D at the output of the second 10b source allows us to obtain a spatially and temporally coherent second 11b X-ray flux, which, as described below, enables the determination of the image by phase contrast.

[0126] Furthermore, in the second imaging configuration, the compression tablet 22 is spaced from the second X-ray source 10b by a distance dlb between 0 cm and 20 cm, preferably between 10 cm and 20 cm, in order to set a magnification value of 100 for the device in the second imaging configuration, which will be explained below. This distance dlb is determined between an emission plane Pib of the second X-ray source 10b. Preferably, an emission plane Pib of the second X-ray source 10b is oriented perpendicular to the propagation axis Ab of the second X-ray source 10b (or perpendicular to the z-axis) and a plane P2b of the compression tablet 22 oriented parallel to the emission plane Pib of the second X-ray source 10b and preferably perpendicular to the propagation axis Ab of the second X-ray source 10b.Here, this plane P2b coincides with the plane of the second principal surface 25 of the compression tablet 22. Alternatively, the propagation axis Ab is slightly inclined at an angle of inclination within a range, for example, from -15 degrees to +15 degrees, with respect to the vertical axis z. For example, in a tomosynthesis application, the source is inclined while keeping the detector horizontal in some configurations. In other configurations, both the source and the detector are inclined. In yet another configuration, the axis of the source remains vertical and only the detector is inclined.

[0127] Finally, in this second imaging configuration, the X-ray image detector 30 is positioned at a distance d2b from the second X-ray source 10b of between 80 cm and 1.70 m, preferably between 80 cm and 1.50 m from the second X-ray source 10b. This distance d2b is determined between the emission plane Pib of the second X-ray source 10b and the plane P3 of the X-ray image detector 30, preferably oriented parallel to the emission plane Pib of the second X-ray source 10b and preferably perpendicular to the propagation axis Ab of the second X-ray source 10b. For example, this plane P2b coincides with the plane of the second main surface 25 of the compression tablet 22. The active surface 31 of the X-ray image detector 30 lies within the plane P3 described above. Alternatively, the propagation axis Ab is slightly inclined at an angle of inclination within a range, for example from -15 degrees to +15 degrees, with respect to the vertical axis z and the normal to the active surface 31 of the X-ray image detector 30 is inclined at the same angle of inclination.

[0128] The distance dlb second source 10b - compression tablet 22 and the distance second source 10b - X-ray image detector 30 allow a second optical magnification of the device 100 to be defined as the ratio between the distance d2b (distance separating the second 10b X-ray source from the X-ray image detector 30) and the distance dlb (distance separating the second 10b X-ray source from the compression tablet 22).

[0129] In particular, in this configuration, the second optical magnification of the apparatus 100 is greater than or equal to 8 and less than or equal to 30. Preferably, the second optical magnification of the apparatus 100 is between 8 and 20, and even better between 8 and 15, in order to obtain a better resolution on the phase contrast image reconstructed by the apparatus 100.

[0130] It is thus understood that the second optical magnification is greater than the first optical magnification.

[0131] To obtain such a magnification variation, firstly, the detector 30 is mounted to move in translation along the z-axis.

[0132] In one embodiment, the compression tablet 22 and the breast platform 20 remain in a fixed z-position for a given patient between the first and second imaging configurations. In this case, the source support 62 is mounted to move in translation along the z-axis.

[0133] In another embodiment, the source support 62 remains in a fixed z-position between the first and second imaging configurations. In this case, the compression tablet 22 and the breast platform 20 are mounted to move in translation along the z-axis. However, for this movement to be possible, it is understood that the patient's distance from the ground must be changed. To this end, the device 100 includes at least one other platform or wedge 110 arranged to support the patient upright and modify the distance between the patient and the ground. This wedge 110 can support the patient at foot level.For this purpose, this wedge can be in the form of a platform on which the patient stands and can be positioned along the z-axis by the control unit 51 in order to synchronize the movement of the compression plate 22 and the breast support 20 with the patient's distance from the floor. Of course, in a variant, it is possible to use multiple interlocking or individual wedges and select the one that allows the patient's position relative to the floor to be adjusted with the movement of the breast support 20 and the compression plate 22.

[0134] Advantageously, the device 100 also includes an adjustment device in position 63 of the wedge 110 configured to move the wedge 110 along at least one spatial direction, corresponding here to a translation of the wedge 110 along the z-axis between the first and second imaging configurations.

[0135] In yet another embodiment, the source support 62, the compression tablet 22 and the platform 20 for breast are each mounted movable in translation along the z-axis, as well as optionally the wedge 110.

[0136] For example, in the first imaging configuration, it is sufficient to adjust, manually or automatically, at least one of the distances dla, d2a, and in the second imaging configuration, at least one of the distances dlb, d2b. Preferably, the distances dla, d2a, dlb, d2b are adjusted using the human-machine interface. In this case, the user enters, for example, the distance dlb (corresponding here to an input value) into the human-machine interface, and the control unit automatically moves the compression tablet 22 and the breast support 20.

[0137] To this end, the apparatus 100 includes, for example, a position adjustment device 60 for the breast platform 20 and the compression tablet 22, for adjusting the position of the breast platform 20 and the compression tablet 22 along at least one spatial direction. Here, the at least one spatial direction corresponds to a translation of the breast platform 20 and the compression tablet 22, that is, a translation along the z-axis (parallel to the propagation axis of the X-ray source used), with respect to: - to the first X-ray source 10a, so as to obtain the first optical magnification, or - to the second 10b X-ray source, so as to obtain the second optical magnification.

[0138] Such a configuration thus makes it possible to move the platform 20 for breast as well as the compression tablet 22 between the first imaging configuration and the second imaging configuration or vice versa.

[0139] Typically, this positioning adjustment device 60 may include a movable support 60a on which the breast platform 20 is mounted and another movable support 60b on which the compression plate 22 is mounted. The movable support 60a is arranged to move the breast platform 20, and the movable support 60b is arranged to move the compression plate 22, along the translation axis (z-axis) and change its position by translation along the axes transverse to the z-axis, here the x and y axes. Of course, in one embodiment, the breast support 20 and the compression plate 22 may be mounted on a single movable support 60 to simultaneously move the compression platform 22 and the breast platform 20.

[0140] Of course, this positioning device 60 can be moved manually or automatically by using at least one motor configured to move at least one movable support. Typically, this positioning device 60 is controlled by the control unit 50 in order to obtain the desired position and orientation.

[0141] The apparatus 100 also includes an adjustment device in position 61a of the X-ray image detector configured to move the X-ray image detector 30 along at least one spatial direction, corresponding here to a translation of the X-ray image detector 30 relative to: - the first X-ray source 10a, so as to obtain the first optical magnification, or - the second 10b X-ray source, in order to obtain the second optical magnification.

[0142] Such a configuration thus makes it possible to move the X-ray image detector 30 between the first imaging configuration and the second imaging configuration, or vice versa. This position adjustment device 61 can operate similarly to the position adjustment device 60 described above. Namely, it can include a movable support 61a for changing the position of the X-ray image detector 30 along the z-axis and optionally along the x and y axes, either manually or automatically by being motorized.

[0143] In combination or alternatively, the apparatus 100 may include an orientation adjustment device 61b of the X-ray image detector 30 to adjust at least one orientation of the X-ray image detector 30 according to at least one angle of rotation.

[0144] Typically, the position and / or orientation adjustment device 61 is part of the same device and may include a movable support 61 arranged to move the X-ray image detector 30 along the translation axis (z-axis) and change its position by translation along the axes transverse to the z-axis, here the x, y axes and / or its orientation by rotation around the x, y and / or z axes, by means of rotation elements fixed to the movable support 61.

[0145] The joint adjustment in orientation of the X-ray source and the detector makes it possible to obtain images of the breast in a vertical, oblique or even horizontal position.

[0146] It is thus understood that, in the first or second given imaging configuration (for example here the second imaging configuration), it is possible to change both the position of the given X-ray source (here for example the second X-ray source) by moving the considered X-ray source to different points (or positions) Tl-Tn on the source support 62 and to similarly modify the orientation, and optionally the position, of the image detector 30 of X-rays (here by at least one rotation about the x or y axis and optionally a translation along the x axis) via the position and orientation adjustment device 61 of the X-ray image detector so as to produce several absorption images in the first configuration or phase-contrast images in the second configuration depending on or independently of the movements of the source. For this purpose, the position of each of the two sources in the xz plane is changed. In particular, in the first configuration, the position of source 10a is changed according to the different Tn positions to perform tomosynthesis. In the second configuration, the position of source 10b is also changed according to the different Tn positions. Typically, at each given Tn point, a phase-shift image is determined by the processing unit 40. Although only four Tn positions are illustrated in [Fig.[3] A larger number of Tn points is generally used depending on the trajectory defined by the source support 62. Typically, the source support is arranged so that all the Tn points defined by the shape or trajectory of the source support 62 form a total arc between 10 and 50 degrees (preferably between 20 and 40 degrees), here ±20 degrees (°) relative to a reference point Tref on the source support. This reference point can be positioned at the maximum amplitude of the shape of the source support 62 in the case where the support 62 is arc-shaped, or at the intersection between the axis normal to the center of the detector and the support 62 in the case where the support 62 is linear. Here, for example, a phase image is determined at each of the Tl-Tn imaging positions, generally at the same dose at each position and for the same exposure time.Preferably, between each position, the control unit 51 is arranged to deactivate the X-ray source used for safety reasons and to limit the radiation dose delivered to the patient.

[0147] For example, in the first imaging configuration, the processing unit can determine, from each absorption image recorded in the first configuration at a given Tn position, for a series of different Tn positions, a pseudo-3D radiographic image of the patient's breast based on a pseudo-3D absorption mammographic image using a tomosynthesis algorithm. Similarly, in the second imaging configuration, the processing unit can determine, from each phase-contrast image determined at a given Tn position, for a series of different Tn positions, a pseudo-3D radiographic image of the breast based on a pseudo-3D phase-contrast image using a tomosynthesis algorithm.

[0148] In practice, the movement of the given X-ray source at each point can be controlled by the control unit 51. For this purpose, the points Tn can be defined as input data for the human-machine interface by defining a number of points Tn and by defining a value in degrees between each point Tn or a total arc value in degrees (defining the trajectory of the total displacement of the given X-ray source along the source support), said control unit 51 being configured to calculate the position and spacing of each point Tn on the source support 62. Alternatively, these displacements can be carried out manually using, for example, an angular graduation defined on the source support 62.

[0149] Similarly, the apparatus 100 may also include a position adjustment device 64 of the source support 62 to adjust a position of said source support 62 relative to the X-ray image detector 30, at least along the translation axis (z-axis).

[0150] Typically, this adjustment device 64 can operate in a similar manner to the position adjustment device 61 of the X-ray image detector 30.

[0151] In a preferred embodiment, the source support 62 is fixed along the x-axis, parallel to the translation axis of the breast platform 20 and / or the compression tablet 22. Thus, to obtain the desired magnification, only the breast platform 20, the compression tablet 22, the wedge 110 and optionally the X-ray image detector 30 are mobile via the mobile supports 60, 61 described above.

[0152] Optionally, the apparatus 100 includes a support 70 on which are mounted at least the breast platform 20, the compression tablet 22, and the X-ray image detector 30, and optionally the position adjustment device 64 for the source support 62. Typically, this support 70 includes a support 71, for example in the form of a translation rail oriented parallel to the translation axis of the compression tablet 22, i.e., vertically with respect to the ground. On this rail 71 are mounted the breast platform 20, the compression tablet 22 via the movable support 60, the image detector 30, or the movable support 61 for the image detector 30 (if present), and optionally the position adjustment device for the source support, if present.

[0153] As illustrated in [Fig. 1], the support 70 may also include a retaining element 72 (for example a retaining plate) oriented perpendicular to the rail 71 and enabling the device 100 to be stabilized.

[0154] Optionally, the device 100 also includes a retaining device 80 for the support on the ground. In practice, this retaining device 80 is attached to the support 70 (here by means of a retaining element 72 of the support 70). In a preferred embodiment, the retaining device 80 is fixed to the ground, for example, by means of feet, here distributed along the surface of the retaining element 72. Advantageously, the device support bracket 80 also includes casters 81 so that the device can be moved easily.

[0155] As illustrated in [Fig.6], the second X-ray source 10b emits the second X-ray flux 11b propagating along a propagation axis Ab. The propagation axis Ab is here preferably oriented vertically and directed towards the ground in order to better secure the device 100 and to reduce the radiation dose emitted outside the device 100.

[0156] The second 10b X-ray source is a so-called microfocus source, which has a spot diameter Db (at the output of the second 10b source) between 1 pm and 20 pm. The second 10b X-ray source is, for example, a source based on an X-ray tube comprising an anode and a cathode. Such a microfocus source is, for example, marketed by Hamamatsu. The second 11b X-ray flux is emitted here at energies between 10 keV (corresponding to a wavelength of 0.12 nm) and 80 kV (corresponding to a wavelength of 0.015 nm), preferably between 20 keV and 80 keV for a cathode current greater than 100 pA. In general, the anode of the second 10b X-ray source comprises at least one heavy material, for example, at least one of the following materials: copper, molybdenum, tungsten. In our example, the anode material is molybdenum.In this case, the second 10b X-ray source generates a continuous X-ray emission spectrum with an emission peak around 17 keV corresponding here to the molybdenum emission lines, by applying a high voltage on the cathode between 40 kV and 80 kV, with a current intensity greater than 100 pA and a power greater than 5W.

[0157] In the second imaging configuration, the second X-ray flux 11b, exiting the second X-ray source 10b, has a power greater than or equal to 5 W and generally less than 100 W. The second X-ray source 10b also emits the second X-ray flux 11b within an emission cone specific to that source 11b. Here, by emission cone is meant a cone of revolution about a propagation axis Ab, having as its generator the diameter Db of the emission spot and having an apex angle or aperture angle at the exit of the second X-ray source 10b. The emission cone represents the volume in which the second X-ray flux 11b propagates from the second X-ray source 10b towards a portion of the patient's breast that is immobilized between the platform 20 and the compression tablet 22.In other words, the second 11b X-ray flux exiting the second 10b X-ray source is divergent, and propagates along the emission cone of the second 10b X-ray source.

[0158] Preferably, the total opening angle of the emission cone of the second 10b X-ray source is between 5 degrees and 45 degrees, and preferably between 10 degrees and 45 degrees.

[0159] The second X-ray flux 11b propagates in a free field from the second X-ray source 10b to the compression plate 22 of the device 100. The second X-ray flux 11b passes through the compression plate 22, the portion of the breast part 1, and the breast platform 20. It is understood that the compression plate 22 and the breast platform 20 are also transparent to the wavelength range emitted by the second X-ray source 10b.

[0160] It is noted that the second 11b X-ray flow has a second initial wavefront representing its propagation at the output of the second 10b X-ray source. This second 11b X-ray flow propagates towards the patient's breast 1 which is held, as in the first imaging configuration, by the compression tablet 22 and the breast platform 20.

[0161] As illustrated in [Fig. 6] or [Fig. 7], only a portion of the compressed breast is irradiated by the second 11b X-ray beam. This portion is included within the part of the breast that was irradiated by the first 11a X-ray beam described above. Thus, only this portion of the breast is contained within the emission cone of the second 11b X-ray beam. In particular, the region targeted by the second 11b X-ray beam corresponds to an area identified as suspicious and / or containing suspicious breast microcalcifications in the absorption mammography image obtained in the first imaging configuration on the same device 100.

[0162] In the example of the microfocus source described above, the second 10b X-ray source is configured to irradiate breast 1 for a time period of between 10 seconds and 120 seconds in order to have enough signal to determine the phase shift image which will be described below.

[0163] Here, in this example, the portion of the part of the breast containing microcalcifications is irradiated for 35 seconds in order to have a good compromise between dose administered to the patient and amount of signal acquired to determine the image of the phase shift.

[0164] The second X-ray source 10b is configured to irradiate the portion of the breast containing the microcalcifications with an X-ray dose, for example, between 400 pSv and 650 pSv. Such a range makes it possible to limit the X-ray dose received by the patient in accordance with health and safety standards while providing sufficient signal to allow rapid acquisition of the phase-shift image of the portion of the patient's breast.

[0165] In this second embodiment, no optical element (other than the compression tablet 22 and the breast platform 20) is positioned in the optical path of the second flow 11b passing through the breast. Thus, the second X-ray flow 11b passing through the breast and propagating between the breast support 20 and the X-ray image detector 30 is in free-field propagation (i.e., it propagates in free space).

[0166] Using free-field propagation reduces the cost of the device 100 used in the second imaging configuration because fewer components are required in the device 100 used in this configuration. Furthermore, it facilitates the determination of the phase shift image.

[0167] In this second imaging configuration, the X-ray image detector 30 is arranged to capture the second X-ray flux 11b that has passed through breast 1 (here, the portion of the breast). It is understood that the second X-ray flux 11b captured by the X-ray image detector 30 has a wavefront, hereafter referred to as the second transmitted wavefront, which represents a spatial distribution of the second X-ray flux 11b that has passed through breast 1.

[0168] The spatial distribution of the transmitted wavefront (captured by the X-ray image detector 30) of the second 11b X-ray stream corresponds to an interference signal (i.e. amplitude) exhibiting a phase shift between the initial wavefront of the second 11b X-ray stream emitted by the second 10b X-ray source and a wavefront of the 11b X-ray stream that was modified during its passage through the patient's breast 1.

[0169] This spatial distribution of the transmitted wavefront which is captured by the X-ray image detector 30 corresponds to an interference signal (i.e. intensity).

[0170] This second 11b X-ray flow is then analyzed by the processing unit 40 to determine a second image of the phase shift corresponding to the intensity image of the second 11b X-ray flow having passed through the patient's breast.

[0171] Figure 9 illustrates a cross-sectional example of a second phase-shift image Imgb of a portion of the compressed breast determined by the processing unit 40 from the second X-ray flux 11b captured by the X-ray image detector 30. More specifically, Figure 9 represents an intensity profile of the X-rays captured on the image detector 30 by a plurality of pixel lines extending, for example, along the x-axis. The breast portion analyzed in this example is the portion of the breast that was irradiated by the X-rays from the second X-ray source 11b.

[0172] As illustrated, the intensity image Imgb has a main bulging portion PSb, representing the intensity of the X-ray beam passing through the sample, framed by two edges PSb in which the intensity signal exhibits a dip followed by a peak corresponding to the interference between the beam passing through the inner and outer edges of the sample. These edges 6 are, in the following, referred to as the edge-enhanced effect.

[0173] As illustrated in [Fig. 9], enhanced edge effects are visible in the intensity image. Refraction of the X-ray beam at the edges of the sample, where the lateral gradients of the X-ray phase are greatest, causes intensity variations that are exploited to enhance the internal and external contours (or edges) of the sample.

[0174] The observed edge enhancement can be interpreted more rigorously using the wave nature of X-rays and Fresnel's diffraction theory. From this perspective, the intensity distribution on the image detector 30 is the result of the interference of waves with a variable phase shift as they pass through the sample under study. At distance d2b, the intensity distribution, after transmission through the immobilized portion of the breast, is described by a formula which, for a weakly absorbing portion of the breast, can be written as follows:

[0175] I(x,y,z)=l+ Xz / 2ir A_± <e>(x,y,0)

[0176] where I is the intensity of the detected radiation, X the wavelength of the X-rays and <e>(x,y) the studied ground phase on which the two-dimensional Laplace operator A acts in the xy plane.

[0177] The measured intensity here is not a direct measurement of the phase, but rather the Laplacian of the phase of the wavefront, denoted hereafter as transmitted wavefront, which represents a spatial distribution of the second 11b flux of X-rays transmitted through the portion of the immobilized breast part 1.

[0178] In practice, in the second configuration of the apparatus 100, the two edges depend on the second optical magnification described above. Thus, it is understood that the second optical magnification of the apparatus 100 in the second configuration is suitable for visualizing the edges of the sample in intensity. Indeed, the two edges PSb are visible only when the propagation distance to the detector 30 is sufficient and the diffraction operates in the Fresnel regime.

[0179] The processing unit 40 illustrated in [Fig. 7] is at least connected to the X-ray image detector 30 described above. By connected, we mean that the processing unit 40 is arranged to communicate with another element, for example, by being configured to transmit and / or receive data from that element (here, for example, via a wired connection). In this case, the processing unit 40 is configured to determine a phase-shift image from the intensity image captured by the X-ray detector 30 in the second imaging configuration, this intensity image being representative of the wavefront of the second transmitted X-ray flux 11b. In the second imaging configuration, the processing unit 40 is configured to reconstruct, from this enhanced-edge intensity image Imgb (or phase-contrast image), a phase image of the immobilized portion of the breast 1.

[0180] In practice, the processing unit 40 is configured to extract the Laplacian of the phase of the signal using phase extraction techniques known to those skilled in the art, for example as described in the paper Burvall, A., Lundstrôm, U., Takman, PA, Larsson, DH, & Hertz, HM (2011), “Phase retrieval in X-ray phase-contrast imaging suitable for tomography”.

[0181] The processing unit 40 is also configured to reconstruct a phase-contrast image from the Laplacian of the signal phase. Here, this phase-contrast image is a free-propagating phase-contrast image obtained from the intensity image of the second 11b X-ray flux transmitted through the portion of the breast irradiated by the second 11b X-ray flux.

[0182] Of course, it should be noted that the main PSb part of the recorded signal can be analyzed and processed by the processing unit 40 to reconstruct an absorption image of the breast part as described in the first imaging setup.

[0183] Of course, if the processing unit 40 also reconstructs an absorption image (as in the case of [Fig.9]), it can also determine the presence of spots in this latter image in a similar way to the method used for the phase contrast image of the sample.

[0184] In the second imaging configuration, the specific arrangement of the apparatus 100, particularly its second optical magnification, allows for the precise visualization of the enhanced edges (i.e., the secondary parts PSb) present in the intensity image Imgb. Indeed, for a lower second magnification (particularly less than 8), these edges are barely or weakly visible in the intensity image, as can be seen in [Fig. 4] associated with the first imaging configuration. Consequently, the intensity X-ray image obtained with a magnification greater than or equal to 8 and less than 30, and preferably between 8 and 15, is much more precise and allows for the extraction of a high-contrast, highly spatially resolved phase-contrast image.

[0185] Figure 10 shows, at the top, three X-ray images (10A, 10B, 10C) of a microcalcification in a portion of the breast of different patients obtained by absorption radiography (noted Abs.), and, at the bottom, three X-ray images (10D, 10E, 10F) of the same microcalcifications in the same portions of the breast obtained by phase contrast radiography (noted C. Ph.). Each column of images in Figure 10 corresponds to the same microcalcification in the same portion of the breast of the same patient. The three columns of images in Figure 10 correspond to different patients. The three absorption images 10A, 10B, 10C are obtained with the 100 apparatus in the first configuration, for example with a magnification of 15. The phase contrast images 10D, 10E, 10F are obtained with the same 100 apparatus in the second configuration with the same detector 30, for example with a magnification of 15. In this example, the same magnification is used in both imaging configurations, but not the same source spot size: in the first configuration, for absorption images, the X-ray source spot 11 is 100p, and in the second configuration, for phase-contrast images, the diameter of source 11b is 10p. Each image allows visualization of one or more X-ray opaque elements 91, 92, 92, 94, 95, for example, breast microcalcifications. As illustrated in [Fig. 10], different objects are extracted from the phase-contrast image and the absorption image.

[0186] However, a comparison of the absorption and phase-contrast images in [Fig. 10] shows that, in each case, the phase-contrast image exhibits better contrast and resolution compared to the absorption image. For example, in the image pair (10A, 10D), an object 91 opaque to X-rays is detected in the absorption image 10A, while the phase-contrast image 10D shows that the contours of this object 91 are irregular. In the example of the image pair (10B, 10E), two objects 92, 93 opaque to X-rays are detected in the absorption image, while the phase-contrast image shows that the contours of these two objects 92, 93 are regular, in the shape of a rhombus or diamond.In the example of the pair of images on the right, two spots 94, 95 partially opaque to X-rays are detected in the absorption image, and these two spots 94, 95 are observed to be diffuse and have irregular contours, for example, a filamentary shape for spot 95. In all cases, the phase contrast image is much sharper than the absorption image.

[0187] Typically, these microcalcifications can then be classified into different classes, for example, according to the morphology of the spots detected in the images described above. In particular, the detected spots are classified according to their shape, which can be regular, for example, round or diamond-shaped, or irregular, possibly exhibiting asperities, depressions, or filaments. The radiologist or physician can then associate a particular spot shape with a low risk of pathology or with a risk of a specific pathology.

[0188] It is understood that since the resolution and contrast of the phase contrast image are better than those of the absorption image, detection and / or sorting from the phase contrast image is more precise and therefore allows for better results.

[0189] Typically, the edge detection algorithm can be based on at least the following algorithms: - a segmentation using a histogram; - a Laplace algorithm; - a gradient algorithm, etc.

[0190] As illustrated in [Fig. 10], various objects 91, 92..., 95 are extracted from the phase-contrast image and the absorption image. Comparison of the absorption and phase-contrast images in [Fig. 10] shows that the phase-contrast image exhibits better contrast and resolution compared to the absorption image obtained.

[0191] Typically these objects 91, 92..., 95 can then be classified into different classes, by the processing unit 40, for example according to the morphology of the objects detected in the images described above.

[0192] It is understood that since the resolution and contrast of the phase contrast image are better than those of the absorption image, detection and / or sorting from the phase contrast image is more accurate and therefore allows for better results.

[0193] Figures 11 to 14 illustrate a second embodiment of a device 200 according to the present invention. The device 200 comprises all the elements of the device 100 described above. [Fig. 11] and [Fig. 12] schematically represent the device 200 in the first imaging configuration. [Fig. 13] and [Fig. 14] schematically represent the device 200 in the first imaging configuration.

[0194] Unlike device 100, device 200 comprises a movable housing 90 associated with the support 70 and housing at least the source holder, the first X-ray source 10a, the rail 71 described above, the X-ray image detector 30, and the various positioning and / or orientation adjustment devices described above. As can be seen in this figure, the breast platform 20 and the compression plate 22 are outside the housing to allow the patient's breast 1 to be positioned in device 200.

[0195] As illustrated, the support 70 is fixed to an inner face of the housing 90, for example by means of screws. It is understood that in this case, the retaining means 72 for the support 70 can correspond to an inner face of the housing 90 or be fixed to this same inner face of the housing 90.

[0196] Here, the retaining device 80 is fixed to an outer face of the housing 90.

[0197] The housing 90 may include closable opening elements to provide access to the various components within the housing 90 for maintenance purposes. Typically, the closable opening elements may be plates fixed to the housing 90 by means of screws or doors that are closable and / or held in place by means of screws.

[0198] In this embodiment, it can be seen that the screen 53 is an element external to the housing 90. Similarly, it can be understood that the control unit 51 can be a computer positioned outside the housing 90 and having a screen 53 serving human-machine interface. Preferably, the screen 53 is positioned a few meters from the device 200 and placed behind a screen, for example leaded glass, to protect the operator from X-rays.

[0199] Process

[0200] An example of a 300 X-ray imaging method using absorption imaging and phase contrast imaging using [Fig. 15] will be written.

[0201] The method illustrated in [Fig.15] is implemented in apparatus 100 or apparatus 200 described above.

[0202] First, the device 100, 200 is placed in the first imaging configuration. For this purpose, the patient is placed in front of the device 100, 200 so as to immobilize part of a breast 1 between the platform 20 and the compression tablet 22. The first X-ray source 10a, the platform 20, the compression tablet 22, the wedge 110 and the detector 30 are arranged as described above to be in the first imaging configuration, the device 100, 200 having a first optical magnification greater than or equal to 1 and less than or equal to 2.

[0203] Method 300 then includes an emission step Ela of the first X-ray flux 1 la from the emission spot of the first X-ray source 10a. As specified above, the emission spot of the first X-ray source 10a has a diameter Da greater than or equal to 50 pm. The first X-ray flux 1 la is emitted towards the portion of the patient's breast 1 immobilized between the platform 20 and the compression tablet 22.

[0204] Here, the first X-ray flux 1 propagates in a free field towards the immobilized patient's breast 1.

[0205] Method 300 also includes a detection step E2a of a first image Imga of X-rays in absorption via detector 30. As previously stated, detector 30 is spaced from the first X-ray source 10a by a distance d2a ranging from 50 cm to 120 cm, preferably greater than or equal to 60 cm and less than or equal to 80 cm.

[0206] The X-ray image detector is in this step arranged to capture the first stream 1 of X-rays transmitted through part 1 of the patient's breast.

[0207] In the first imaging configuration, the immobilized patient's breast part 1 is positioned between the first X-ray source 10a and the image detector 30 so that the first intensity image or absorption image acquired has a first optical magnification greater than or equal to 1 and less than or equal to 2.

[0208] This gives us a first image of absorption of part of the patient's breast 1.

[0209] Method 300 preferably includes an E3a processing step of the absorption image acquired in the first imaging configuration to determine a portion of the patient's breast part 1 to be analyzed with higher magnification in the second phase-contrast imaging configuration. For example, this breast part contains a suspicious focus of microcalcifications.

[0210] Next, the apparatus 100, 200 is placed in the second imaging configuration. The breast portion 1 remains immobilized between the platform 20 and the compression shelf 22 of the same apparatus 100, 200. The second X-ray source 10b, the platform 20, the compression shelf 22, the wedge 110 and the detector 30 are arranged as described above to be in the second imaging configuration, the apparatus 100, 200 having a second optical magnification greater than or equal to 8 and less than or equal to 30, preferably between 8 and 20, and even better between 8 and 15.

[0211] Method 300 then includes an emission step Elb of the second X-ray flux 11b from the emission spot of the second X-ray source 10b. As specified above, the emission spot of the second X-ray source 10b has a diameter Db between 1 pm and 20 pm. The second X-ray flux 11b is emitted towards a portion containing microcalcifications of the part of the patient's breast 1 immobilized between the platform 20 and the compression tablet 22.

[0212] Here, the second 11b X-ray flow propagates in a free field towards the portion of the immobilized patient's breast part 1.

[0213] Method 300 also includes a detection step E2b of a second intensity X-ray image Imgb via detector 30. As previously stated, detector 30 is spaced from the second X-ray source 10b by a distance d2b greater than or equal to 80 cm and less than or equal to 1.7 m and preferably between 80 cm and 1.5 m.

[0214] The X-ray image detector is in this step arranged to capture the second 11b stream of X-rays transmitted through the portion of the part of the patient's breast 1.

[0215] In the second imaging configuration, the portion of the immobilized patient's breast part 1 is positioned between the second X-ray source 10b and the image detector 30 so that the second intensity-acquired Imgb image has the second optical magnification greater than or equal to 8 and less than 20, preferably between 8 and 15 to obtain better performance in terms of contrast and spatial resolution.

[0216] Method 300 also includes a processing step E3b of the second Imgb image acquired by detector 30 to determine a phase shift image and reconstruct, from this phase shift image, a phase contrast image of the portion of the immobilized patient's breast part 1.

[0217] The present invention is in no way limited to the embodiments described and represented, but a person skilled in the art will be able to make any variation in accordance with the invention.< / e> < / e>

Claims

1. Demands X-ray mammography apparatus (100, 200) using two X-ray sources, said apparatus comprising at least: a breast platform (20) and a compression tablet (22) arranged to position and immobilize a portion of a patient's breast (1); a first movable X-ray source (10a) arranged in a first imaging configuration to emit, from an emission spot having a diameter greater than or equal to 50 pm, a first X-ray flux (11a) towards a portion of the patient's breast (1), the breast portion being immobilized between the platform (20) and the compression tablet (22), the first imaging configuration having optical magnification; a second movable X-ray source (10b) arranged in a second imaging configuration to emit, from an emission spot having a diameter between 1 pm and 20 pm, a second X-ray flux (11b),the second X-ray beam (11b) being directed towards a portion of the immobilized patient's breast, an X-ray image detector (30) arranged in the first imaging configuration to capture the first X-ray beam (1a) transmitted through the breast and, respectively, in the second imaging configuration to capture the second X-ray beam (11b) transmitted through the portion of the breast, the platform (20) and the compression tablet (22) being located between the X-ray image detector (30) and the first X-ray source (10a) in the first imaging configuration or, respectively, between the X-ray image detector (30) and the second X-ray source (10b) in the second imaging configuration, a source holder (62) on which the first X-ray source (10a) and the second X-ray source (10b) are mounted,said source support being arranged to alternately position the first X-ray source (10a) in the first imaging configuration and the second X-ray source (10b) in the second imaging configuration, a control unit (51) configured to activate the first X-ray source (10a) in the first imaging configuration or the second X-ray source (10b) in the second imaging configuration, said activation of the first X-ray source, or of the second X-ray source being carried out alternately, said apparatus (100, 200) having in the second imaging configuration a distance between the second X-ray source and the X-ray image detector (30) of between 80 cm and 1.6 m and an optical magnification greater than or equal to 8 and less than 20, the optical magnification of the second imaging configuration being greater than the optical magnification of the first imaging configuration, and a processing unit (40) configured to determine an absorption mammographic image of the portion of the patient's breast from the first X-ray stream captured by the X-ray image detector (30) in the first imaging configuration and to reconstruct, from the second X-ray stream captured in the second imaging configuration, a phase-contrast image of the portion of the patient's breast.

2. Apparatus (100, 200) according to claim 1, said apparatus (100, 200) has in the first imaging configuration a distance between the first X-ray source (10a) and the detector (30) of between 50 cm and 120 cm and the optical magnification greater than or equal to 1 and less than or equal to 2.

3. Apparatus according to claim 1 or claim 2, wherein, in the second imaging configuration, the second X-ray stream transmitted through the compression tablet (22) and platform (20) propagates in a free field towards the X-ray image detector (30).

4. Apparatus according to any one of claims 1 to 3, wherein the source holder (62) has a rail and wherein the control unit is configured to move at least the first source (10a) and the second source (10b) along the rail of the source holder so as to position: i) either the first X-ray source in the first imaging configuration, ii) or the second X-ray source in the second imaging configuration.

5. Apparatus according to any one of claims 1 to 4, wherein, in the first imaging configuration, the X-ray image detector (30) is positioned opposite the first X-ray source (1la), and in the second imaging configuration, the X-ray image detector (30) is positioned opposite the second X-ray source (11b).

6. Apparatus according to any one of claims 1 to 5, wherein, in the first imaging configuration, the first X-ray source is arranged to emit the first X-ray flux in a cone of emission around a propagation axis oriented vertically and directed towards the ground, and wherein, in the second imaging configuration, the second X-ray source is arranged to emit the second X-ray flux in a cone of emission around a propagation axis oriented vertically and directed towards the ground.

7. Apparatus according to any one of claims 1 to 6, wherein the X-ray image detector comprises a pixel array having a first spatial dimension and a second spatial dimension, the first spatial dimension being greater than or equal to 10 cm and the second spatial dimension being greater than or equal to 10 cm.

8. Apparatus according to any one of claims 1 to 7, wherein the processing unit is configured to determine, by using an edge detection algorithm on said phase contrast image, the presence of an object in said phase contrast image and a morphology of each detected object.

9. Apparatus according to any one of claims 1 to 8, comprising at least one of the following: a support (70, 71) on which are mounted at least the source support (62), the breast platform (20) and the compression tablet (22), the X-ray image detector (30), a housing (90) associated with the support (70, 71), the housing (90) accommodating at least the source support (62), the first X-ray source (10a) and the second X-ray source (10b), the breast platform (20) and the compression tablet (22), the X-ray image detector (30), a device for holding the support to the ground.

10. Apparatus according to any one of claims 1 to 9 comprising: an adjustment device (61, 61a, 61b) for the detector (30) configured to move the detector (30) along at least one spatial direction so as to adjust the distance between the detector (30) and the first X-ray source (10a) in the first imaging configuration or so as to adjust the distance between the detector (30) and the second X-ray source (10b) in the second imaging configuration, and / or the adjustment device (61,61a,61b) being adapted to adjust an orientation of the detector (30) by at least one rotation.

11. Apparatus according to any one of claims 1 to 10 comprising a position adjustment device (60, 60a, 60b) of the breast platform (20) and the compression tablet (22), the position adjustment device (60, 60a, 60b) being adapted to adjust a position of the breast platform and the compression tablet relative to the first X-ray source in the first imaging configuration or relative to the second X-ray source in the second imaging configuration.

12. Apparatus according to any one of claims 1 to 11, comprising another device for adjusting the position and / or orientation of the source support (62) to adjust a position of said source support relative to the X-ray image detector (30) along at least one spatial direction, said at least one spatial direction corresponding to a translation of said source support (62) relative to the X-ray image detector and / or to adjust the orientation of the source support (62) relative to the X-ray image detector (30) along at least one angle of rotation.

13. Apparatus according to any one of claims 1 to 12, wherein, in the first imaging configuration, the control unit is configured to move the first X-ray source to different positions along the source support (62) and, for each position, determine a mammographic image by absorption and a phase contrast image.

14. Apparatus according to claim 13, wherein said apparatus is configured to reconstruct: an absorption mammographic image of a portion of the patient's breast by tomosynthesis from at least three absorption images of said portion of the patient's breast, the three absorption images being taken in three distinct orientations and / or a phase-contrast tomosynthesis image of the portion of the patient's breast from at least three phase-contrast images of said portion of the patient's breast, the three phase-contrast images being taken in three distinct orientations.

15. X-ray mammography method comprising the following steps: arrangement of an apparatus (100, 200) according to any one of claims 1 to 14 in a first imaging configuration, the first imaging configuration having optical magnification, the first X-ray source (10a), the breast platform (20), the compression tablet (22), a wedge (110) and the detector (30) being arranged according to the first imaging configuration, a portion of a patient's breast 1 being immobilized between the platform (20) and the compression tablet (22); emission (Ela) of a first flow (lia) of X-rays from the emission spot of the first free-field X-ray source (10a) towards the part of the patient's breast (1) immobilized between the platform (20) and the compression tablet (22), the emission spot of the first X-ray source (10a) having a diameter greater than or equal to 50 pm;detection (E2a) of a first image (Imga) of intensity X-rays via detector (30) to obtain a first absorption image of a part of the patient's breast 1; arrangement of the same apparatus (100, 200) in a second imaging configuration, the second X-ray source (10b), the breast platform (20), the compression tablet (22), the wedge (110) and the detector (30) being arranged according to the first imaging configuration, the part of a patient's breast (1) being immobilized between the platform (20) and the compression tablet (22), said apparatus (100, 200) having in the second imaging configuration a distance between the second X-ray source (10b) and the X-ray image detector (30) of between 80 cm and 1.6 m and an optical magnification greater than or equal to 8 and less than 20, the optical magnification of the second imaging configuration being greater than the optical magnification of the first imaging configuration;emission (E1b) of a second X-ray flux (E1b) from the emission spot of the second free-field X-ray source (E10b) towards a portion of the patient's breast (E1) immobilized between the platform (E20) and the compression tablet (E22), the emission spot of the second X-ray source (E10b) having a diameter between 1 pm and 20 pm; detection (E2b) of a second intensity X-ray image (E1b) via the detector (E30); processing (E3b) of the second image (E1b) to determine an image of the; phase shift and reconstruct, from this phase shift image, a phase contrast image of the portion of the part of the breast (1) of the patient.

Images