Apparatus and method for in vivo breast tissue imaging using coded aperture x-ray scatter tomography

Abstract

A system and method for acquiring in vivo tomographic x-ray scatter data for tissue discrimination of breast tissue. The system includes a coded aperture for spatially coding x-ray scatter originating from within a patient's breast. A detector records a modulated scatter signal, which can be used to reconstruct a spatially resolved estimate of the x-ray scatter spectrum and then generate a spatially resolved tissue type estimate for a user.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 63 / 297,793, entitled "An apparatus and method for in vivo breast tissue imaging used coded aperture X-ray scatter tomography," filed on January 9, 2022, the entire contents of which are incorporated herein by reference in their entirety. [Background technology]

[0002] Existing mammography systems image breast tissue in a transmission mode by measuring the attenuation of an X-ray source penetrating directly through the breast relative to the initial intensity of the X-ray source in one or more energy ranges. Mammograms from existing digital systems are either direct projections of a single view of breast tissue from the X-ray source onto a 2D X-ray detector pixel array, or, in 3D mammography systems, a 3D tomographic X-ray transmission image is calculated from several projection views. In existing mammography systems without energy discrimination, the projection image consists of grayscale values ​​that are effectively controlled by tissue density. Tissue density may be similar enough between cancerous and benign tissue that it is difficult or impossible to distinguish by density alone. In systems with some energy discrimination, which may be achieved either by multi-energy channel detectors or multiple measurements with different source operating parameters or filtering, images composed of more than a single value per pixel may be calculated, providing some additional contrast to the mammogram features. Mammograms from these existing systems are inspected by clinicians for areas that the clinician believes may potentially be malignant tissue. Whether they are true grayscale or multi-energy enhanced transmission-based images, mammograms from existing mammography systems provide limited information upon which clinicians must make a decision as to whether an area of ​​tissue is cancerous; as a result, 70-80% of mammograms that are flagged for biopsy in the United States are ultimately found to be benign upon examination of the biopsy tissue by a pathologist.

[0003] Approximately 30% of new female cancers are breast cancer, and a woman's average lifetime risk of developing breast cancer is approximately 13%. According to the American Cancer Society, if breast cancer is detected early and at a localized stage, women have a 99% five-year relative survival rate. Thus, there is a need for a mammogram system that accurately detects breast cancer.

[0004] The present invention is directed generally to medical imaging, and more specifically, the present invention is directed to mammography and x-ray scattering tomography for producing spatially resolved volumetric x-ray scattering spectral reconstructions.

[0005] Background technology Thus far, the discriminatory power of X-ray scattering measurements of breast tissue has only been demonstrated ex vivo in relatively controlled sample and measurement scenarios, but recent developments in X-ray scattering methodologies employing coded apertures allow spatially resolved volumetric X-ray scattering spectral reconstructions to be implemented in sample and measurement scenarios similar to those of typical mammography systems. In vivo coded aperture-based X-ray scattering imaging systems and methodologies provide clinicians with additional spatially resolved estimates of the likelihood that a region of tissue is cancerous, based on information that would never be accessible in a transmission-only mammography system. Summary of the Invention

[0006] The subject matter described herein includes systems and methods for coded aperture-based X-ray scattering tomography of in vivo breast tissue. According to the systems and methods, spatially resolved volumetric X-ray scattering spectral reconstructions of in vivo breast tissue are used to provide spatially resolved estimates of tissue type. Specifically, these estimates may include the likelihood that a region of breast tissue is cancerous based on a comparison to reference X-ray spectra of benign and cancerous tissue types. Considering that 70-80% of mammograms flagged for biopsy are negative, such estimates provide valuable additional information to assist clinicians in making biopsy decisions. Known prior art does not provide spatially resolved volumetric X-ray scattering spectral reconstructions or derived tissue type likelihood estimates calculated from in vivo X-ray scattering spectral data of breast tissue.

[0007] In contrast to tissue X-ray transmission measurements, which can only provide the same number of features per pixel as the number of effective energy channels in the measurement, spatially resolved volumetric X-ray scattering spectral reconstructions provide as many features as allowed by the energy resolution, the measurement geometry (especially the size of the detector and pixel pitch when acquiring in most angle-dispersive modes), and the accuracy of the model used for reconstruction. These additional features are also nearly orthogonal to those provided by X-ray transmission measurements, i.e., they provide information that is different from any transmission X-ray measurement modality. More importantly, to inform clinicians, transmission X-ray measurements are essentially limited by similar and potentially overlapping density values ​​of malignant and benign tissues, whereas tissue X-ray scattering measurements have been shown to distinguish between cancerous and benign tissues ex vivo.

[0008] The mammography system described herein comprises a movable x-ray source for generating a primary x-ray beam for irradiating a patient's breast. The x-ray source is adjustable based on at least one operating parameter including exposure time, current, voltage, or filtering. The mammography system further comprises a collimator between the x-ray source and the patient's breast for shaping the primary x-ray beam. The collimator includes an aperture having at least one configurable dimension. The mammography system further comprises a plurality of movable breast plates for positioning the patient's breast in the path of the primary x-ray beam. The mammography system further comprises an x-ray detector array including a plurality of movable x-ray detection elements. The x-ray detector array is configurable to position at least one x-ray detection element distal to the x-ray source at a first measurement location in the path of the primary x-ray beam to measure transmitted x-ray radiation from the primary x-ray beam. The X-ray detector array can be configured to position at least one X-ray detector element distal to the X-ray source at a second measurement location outside the path of the primary X-ray beam passing through the patient's breast to measure scattered X-ray radiation from the primary X-ray beam. The mammography system further comprises a coded aperture positioned distal to the X-ray source between the patient's breast and the X-ray detector array, the coded aperture configured to modulate the scattered X-ray radiation from the patient's breast detected by the X-ray detector array. The mammography system can be configured to perform X-ray scatter measurements and X-ray transmission measurements. When performing X-ray scatter measurements, the X-ray detector array is configured such that at least one X-ray detector element of the plurality of X-ray detector elements is positioned outside the path of the primary X-ray beam to detect scattered X-ray radiation from the primary X-ray beam passing through the patient's breast. When performing X-ray transmission measurements, the X-ray detector array is configured such that at least one X-ray detector element of the plurality of X-ray detector elements is positioned to detect X-rays transmitted through the patient's breast from the primary X-ray beam. The mammography system further comprises a control system comprising a memory and a processor configured to configure the mammography system for X-ray transmission or X-ray scatter measurements.Configuring the mammography system includes controlling at least one configuration parameter. The at least one configuration parameter includes a position of an x-ray source, a position of an x-ray detector array, a size of an opening of a collimator, at least one operating parameter of the x-ray source, and a position of a plurality of breast plates. The processor is further configured to receive x-ray transmission data detected by the x-ray detector array. The processor is further configured to generate an x-ray density mammogram image based on the received x-ray transmission data. The processor is further configured to identify a region of interest in the patient's breast based on the x-ray density mammogram image. The processor is further configured to determine at least one scattering configuration parameter for x-ray scatter measurements based on the identified region of interest of the patient's breast. The processor is further configured to configure the mammography system for x-ray scatter measurements based on the at least one determined scattering configuration parameter. The processor is further configured to receive x-ray scatter data detected by the x-ray detector array. The processor is further configured to estimate a spatially resolved x-ray scatter spectrum reconstruction based on the received x-ray scatter data, the received x-ray transmission data, and the at least one scattering configuration parameter. The processor is further configured to determine spatially resolved tissue properties based on the received x-ray scatter data of the region of interest. The processor is further configured to generate a spatially resolved scatter mammogram image based on the received x-ray transmission data and the received x-ray scatter data. There are many potential embodiments of the mammography system, some of which are further described below.

[0009] A method of performing spatially resolved volumetric X-ray scattering tomography mammography as described herein includes performing an X-ray transmission measurement. The X-ray transmission measurement includes transmitting a first primary X-ray beam from an X-ray source through a collimator having an aperture configurable in at least one dimension to shape the first primary X-ray beam and through a patient's breast positioned between a plurality of breast plates. The X-ray source is adjustable based on at least one operating parameter including exposure time, current, voltage, or filtering. The X-ray transmission measurement further includes detecting X-ray radiation from the first primary X-ray beam that has directly transmitted through the patient's breast using at least one X-ray detection element of an X-ray detector array. The X-ray transmission measurement further includes receiving X-ray transmission data from the X-ray detector array via a control system including a processor and a memory. The method further includes generating a radiodensity mammogram image of the patient's breast based on the received X-ray transmission data. The method further includes identifying a region of interest within the patient's breast based on the radiodensity mammogram image. The method further includes determining at least one scatter measurement configuration parameter for an X-ray scatter measurement of the identified region of interest in the patient's breast. The scatter measurement configuration parameters include a position of an X-ray source, a position of the plurality of X-ray detecting elements, a collimator aperture size, an X-ray source operating parameter, and a position of the plurality of breast plates. The method further includes performing an X-ray scatter measurement of the region of interest. The X-ray scatter measurement includes transmitting a second primary X-ray beam from the X-ray source through a collimator to shape the second primary X-ray beam and through the patient's breast positioned with the plurality of breast plates. The X-ray scatter measurement further includes modulating scattered X-ray radiation from the second primary X-ray beam interacting with the patient's breast using a coded aperture positioned between the patient's breast and the plurality of X-ray detecting elements. The X-ray scatter measurement further includes detecting the modulated scattered X-ray radiation using an X-ray detector array. The X-ray scatter measurement further includes receiving X-ray scatter data representative of the detected scattered X-ray radiation from the X-ray detector array.The method further includes calculating a spatially resolved x-ray scatter spectrum reconstruction based on the received x-ray scatter data, the received x-ray transmission data, and the determined scatter measurement configuration parameters. The method further includes determining at least one spatially resolved tissue property based on the received x-ray scatter data of the region of interest. The method further includes generating a spatially resolved scatter mammogram image based on the received x-ray transmission data and the received x-ray scatter data. There are many potential embodiments of the method, some of which are further described below.

[0010] X-ray radiation scattered from breast tissue contains tissue-specific information. More specifically, tissue X-ray diffraction (XRD) spectra reflect local molecular order. For example, adipose, glandular, and cancerous tissues have different molecular orders that result in distinct XRD spectra.

[0011] There are many potential embodiments of the system, some of which are further described below. The system includes at least one X-ray source for irradiating breast tissue. The system also includes at least one collimation stage between the X-ray source and the breast tissue. The system further includes a coded aperture positioned between the breast tissue and the detector. The system further includes a processor that can use the detected X-ray scatter signal modulated by the coded aperture to calculate a spatially resolved estimate of the tissue type of the irradiated breast tissue. Finally, the system can further include a component, e.g., a computer monitor, for presenting the tissue type estimation data to an operator or clinician.

[0012] Molecular order also affects density. In existing transmission mammography systems, local molecular order is generally summarized in a single radiodensity value. However, the mammography system described herein is designed to generate a spatially resolved x-ray scatter spectrum of the region of breast tissue where the scatter measurement and reconstruction are performed. The x-ray scatter spectrum provides more features and increased contrast for differentiation of tissue types compared to existing mammography systems, and the spatially resolved nature of the reconstructed data allows this ability of differentiation to be associated with specific known locations within the patient's breast and thus correlated with observable features in the radiodensity mammogram image generated by the transmission measurement. The irradiance and x-ray energy spectrum reaching the breast tissue can be controlled using filters, which can be done to minimize the dose received by the patient and to improve contrast and x-ray spectral resolution. The cross-sectional shape (e.g., pencil-shaped, fan-shaped, or cone-shaped beam), divergence, and spatial extent of the x-ray beam reaching the breast tissue can be controlled using a collimator between the x-ray source and the breast tissue. Secondly, the scattered x-rays are measured with an x-ray detector. A coded aperture, i.e., a patterned aperture with a known aperture fraction and pattern, is located between the breast tissue and the X-ray detector to selectively and purposefully attenuate the scattered X-rays based on a known code pattern and measurement geometry. Third, a spatially resolved estimate of the tissue type of the irradiated breast tissue is calculated from the detected coded aperture modulated X-ray scattering signal using a processor. Finally, the tissue type estimate is presented to an operator or clinician using a display component. For example and without limitation, the mammography system described herein is designed to generate a color map overlaid on the X-ray transmission image corresponding to the estimated tissue type and / or cancer likelihood. Furthermore, the mammography system may flag regions of the transmission image with a percentage value of cancer likelihood. Advantageously, the mammography system is further operable to measure and display X-ray scatter data of sub-regions of the transmission data (e.g., scatter spot check during transmission expansion mode).

[0013] Spatially resolved volumetric X-ray spectral data can be reconstructed from the irradiated volume using a coded aperture to modulate the scatter, a 2D pixelated detector to measure the modulated scatter signal, a forward matrix model of the physics and geometry of the measurement, and a processor that iteratively estimates the spatially resolved volumetric X-ray spectral data from the forward matrix model by commonly known algorithms (e.g., maximum likelihood estimation). This general procedure is used in the methods described herein. Specifically, this involves estimating momentum transfer spectra on a pixel or voxel basis, which can be compared to reference momentum transfer spectra, such as those of cancerous tissue or benign fat or glandular tissue, or utilized in machine learning classification methods.

[0014] The specific embodiments discussed below are descriptions of system embodiments that include direct transmission measurements and generally have similar geometries, components, and form factors as existing mammography systems.

[0015] The embodiments illustrated, described and discussed herein are exemplary of the present invention. As these embodiments of the present invention are described with reference to the examples, various modifications or adaptations of the described methods and / or specific structures may become apparent to those skilled in the art. It will be understood that modifications and variations are covered by the above teachings and within the scope of the appended claims without departing from the spirit and intended scope thereof. All such modifications, adaptations or variations that rely on the teachings of the present invention and that have advanced the art through these teachings are considered to be within the spirit and scope of the present invention. Therefore, these descriptions and drawings should not be considered in a limiting sense, so that it is understood that the present invention is not limited to only the illustrated embodiments. [Brief description of the drawings]

[0016] [Figure 1] 1 illustrates an exemplary schematic of the general components and layout of an embodiment of a spatially resolved volumetric X-ray scattering tomography mammography system described herein. [Diagram 2] 1 illustrates an exemplary process flow chart for implementing the spatially resolved volumetric X-ray scattering tomography mammography embodiments described herein. [Diagram 3] 1 illustrates a schematic of measured modulated X-ray scattering data, post-acquisition reconstruction calculations, and presentation of a scatter mammogram having a suspected target match with tissue characteristics, in this example cancer, according to one embodiment described herein, including an illustration of the reconstructed scatter spectral dimensions used to calculate tissue characteristics. [Figure 4A] 1 illustrates a collimator in an open position to change the field of view or beam shape, in this example creating a cone-shaped beam, according to one embodiment described herein. [Figure 4B] 1 illustrates a multi-stage collimator that produces a pencil or fan beam, according to one embodiment described herein. [Figure 5A] 1 illustrates a schematic example of a coded aperture for a pencil-shaped beam according to one embodiment described herein. [Figure 5B] 1 illustrates a schematic example of a coded aperture for a fan beam according to one embodiment described herein. [Figure 6A] 1 illustrates a schematic example of a mammography system in which a beam block is separate from and behind a coded aperture, according to one embodiment described herein. [Figure 6B] 1 illustrates a schematic example of a mammography system in which a beam block is separate from and in front of the coded aperture, according to one embodiment described herein. [Figure 6C] 1 illustrates an X-ray system in which a beam block is incorporated within a coded aperture, according to one embodiment described herein. [Figure 7A] 1 illustrates a mammography system in a magnification mode performing transmission measurements and identifying regions of interest in a transmission mammogram of the breast according to one embodiment described herein. [Figure 7B]1 illustrates a mammography system in magnification mode performing scatter measurements of an identified region of interest and generating a scatter mammogram with an indication of tissue characteristics, in this example a spatially resolved estimate of whether the region of interest contains cancerous tissue, according to one embodiment described herein. [Figure 8A] 1 illustrates a mammography system with a rotating coded aperture in a folded position according to one embodiment described herein. [Figure 8B] 1 illustrates a mammography system with a rotating coded aperture in a deployed position, according to one embodiment described herein. [Figure 9A] 1 illustrates a schematic embodiment of a mammography system including a movable transmission detector in an active position according to one embodiment described herein. [Figure 9B] 1 illustrates a schematic embodiment of a mammography system including a movable transmission detector in an inactive position according to one embodiment described herein. [Figure 10A] 1 illustrates an X-ray detector array according to one embodiment described herein. [Figure 10B] 1 illustrates an X-ray detector array including multiple X-ray detectors in a linear orientation, according to one embodiment described herein. [Figure 10C] 1 illustrates an X-ray detector array including a plurality of X-ray detectors in a curved orientation according to one embodiment described herein. [Figure 10D] 1 illustrates an X-ray detector array including multiple X-ray detectors in a spaced apart orientation, according to one embodiment described herein. [Figure 11] 1 illustrates a schematic diagram of a mammography system including a second X-ray source used to perform X-ray scattering measurements according to one embodiment described herein, where the second X-ray source can be oriented for X-ray scattering measurements during magnified and non-magnified mammogram examinations. [Figure 12A]1 illustrates a schematic diagram of a mammography system operating in transmission mode including an X-ray source for X-ray transmission measurements and X-ray scatter measurements using separate X-ray detectors according to one embodiment described herein. [Figure 12B] 1 illustrates a schematic diagram of a mammography system operating in scatter mode including an X-ray source for X-ray transmission measurements and X-ray scatter measurements using separate X-ray detectors according to one embodiment described herein. [Figure 13] 1 illustrates a schematic diagram of a mammography system having a removable coded aperture according to one embodiment described herein. [Figure 14] 1 illustrates a schematic diagram of a mammography system having a removable coded aperture fixed to an enlarged spacer platform according to one embodiment described herein. [Figure 15] 1 illustrates a schematic diagram of a spatially resolved scatter mammogram image generated from X-ray transmission data and X-ray scattering data, including a region of interest from which scatter data is measured and reconstructed, according to one embodiment described herein, including an illustration of reconstructed X-ray scattering spectra of indicated voxels corresponding to different tissue types. [Figure 16] FIG. 1 illustrates a schematic of a spatially resolved scatter mammogram image generated from X-ray transmission data and X-ray scatter data, including a region of interest from which scatter data is measured and reconstructed, colored based on the spatially resolved scatter reconstruction, as illustrated by the hatch scale shown, according to one embodiment described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] For the purposes of facilitating understanding of the present disclosure, reference will be made to preferred embodiments and specific language will be used to describe the same. Nonetheless, no limitation of the scope of the present disclosure is intended thereby, and it will be understood that such changes and further modifications of the present disclosure as exemplified herein are contemplated as would normally occur to one skilled in the art to which the present disclosure pertains.

[0018] The articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, "a composite" means at least one composite and may include more than one composite.

[0019] Throughout this specification, the terms "about" and / or "approximately" may be used in conjunction with numerical values ​​and / or ranges. The term "about" is understood to mean a value close to the recited value. For example, "about 40 [units]" may mean within + / - 25% of 40 (e.g., 30-50), + / - 20%, + / - 15%, + / - 10%, + / - 9%, + / - 8%, + / - 7%, + / - 6%, + / - 5%, + / - 4%, + / - 3%, + / - 2%, within + / - 1%, less than + / - 1%, or any other value or range of values ​​therein or therebelow. Additionally, the phrases "less than about [value]" or "greater than about [value]" should be understood in light of the definition of the term "about" provided herein. The terms "about" and "approximately" may be used interchangeably.

[0020] As used in this specification, the verb "comprise" and its conjugations as used in the specification and claims are used in their open-ended sense to mean that items following the word are included but items not specifically mentioned are not excluded.

[0021] It will be understood that throughout this specification, "comprising" or variations such as "comprises" or "comprising" are meant to imply the inclusion of a stated element, integer, or step, or group of elements, integers, or steps, but not the exclusion of any other element, integer, or step, or group of elements, integers, or steps. The disclosure may, as appropriate, "comprise," "consist," or "consist essentially of" the steps, elements, and / or reagents recited in the claims.

[0022] It is further noted that the claims may be drafted to exclude any optional element, and thus, this declaration is intended to serve as a predicate basis for using exclusive terminology, such as "solely," "only," or "negative" limitations in connection with the recitation of claim elements.

[0023] In the description herein, the measured scattering signals and reconstructed spatially resolved scattering spectra are referred to as being related to "X-ray scattering," although the X-ray scattering field will generally be comprised of both Rayleigh and Compton scattering. The use of the measured scattering signals and reconstructed spatially resolved scattering spectra and similar terminology, and in particular the use of the term "diffraction," is not intended to limit the invention to relating to scattering resulting from one physical process rather than another.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. Preferred methods, devices, and materials are described, but any methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure. All references cited herein are incorporated by reference in their entirety.

[0025] The subject matter described herein is generally directed to mammography, and more specifically to mammography systems that use a coded aperture to modulate scattered x-ray radiation from an irradiated breast of a patient. More specifically, the subject matter described herein is directed to mammography systems that measure modulated scattered x-ray radiation from the breast to estimate a spatially resolved volumetric x-ray scattering tomography spectral reconstruction of the breast. Spatially resolved volumetric x-ray scattering tomography is defined herein as the measurement of x-ray scattering spectra throughout a tomographic image such that each pixel or voxel contains an additional dimension of data that is a spatially resolved scatter measurement. The tomographic image is obtained by performing x-ray scatter measurements. The x-ray scatter measurements include detecting x-ray scatter from tissue and processing the x-ray scatter measurement data to localize the angle and origin of scattered x-rays from within the tissue. Such mammography systems are designed to measure spatially resolved structural differences within a patient at the cellular level as reflected in a spatially resolved volumetric x-ray scattering spectral reconstruction.

[0026] Existing X-ray mammography systems include an X-ray source that generates X-rays and an X-ray detector that captures the X-rays after passing through the patient's tissue. In this way, existing X-ray mammography systems operate in a transmission mode and perform X-ray transmission measurements that are used to generate a mammogram image of the transmission, i.e., X-ray density. The intensity scale of X-ray density is based on the amount of X-rays that have passed through the tissue. The measurement of the X-rays that have passed through the tissue represents the X-ray transmission measurement. X-ray density mammogram images can be two-dimensional or three-dimensional, and three-dimensional mammogram images are tomographically reconstructed from X-ray transmission measurements from multiple views of the tissue. Clinicians evaluate X-ray density mammograms based on the shape and radiodensity of features observed in the tissue. Adipose tissue is less dense than other types of breast tissue, while cancerous tissue may have a density similar to healthy glandular tissue or benign masses. Calcifications in tissue are denser than adipose, glandular, and cancerous tissue, as well as fibromas, but are not a definitive indicator of the presence of cancerous tissue. Thus, cancerous tissue generally cannot be clearly distinguished from healthy tissue in an x-ray density mammogram.

[0027] Beam divergence results in an x-ray beam that is wider in area and less intense at greater distances from the x-ray source. This further causes some magnification of the object being radiographed. The basic principle of transmission x-ray imaging is that x-rays travel in straight lines. However, when x-ray scattering events occur in the patient, the resulting scattered x-rays are not aligned with the trajectory of the original primary x-ray beam. In existing transmission mammography systems, scattered radiation detected by the x-ray detector can be a significant source of image degradation. Scattered radiation produces undesirable image intensities that are not indicative of tissue radiodensity along a straight path from the source in the region of the image where it is detected, which can significantly reduce contrast. Because contrast can be increased in digital radiodensity images by windowing, leveling, or other adjustment schemes, in the case of digital radiography images, scattering primarily serves as a source of noise, degrading the signal-to-noise ratio (SNR).

[0028] Therefore, in transmission mammography, it is typically important to control the amount of scattered radiation that reaches the x-ray detector to create a high quality image. Scattered radiation causes unwanted exposure to the image. To address the unwanted image intensity produced in transmission mammograms by scattered radiation, anti-scatter grids are used to absorb the scattered radiation leaving the patient and reduce the amount of scatter that reaches the image detector. Anti-scatter grids are components placed near the detector and are designed to angularly remove x-rays that do not originate from the x-ray source. Anti-scatter grids block many of the scattered x-rays that are a source of noise or image degradation in transmission measurements. In contrast, for volumetric x-ray diffraction imaging, these scattered x-rays are the desired signal source that needs to be measured. In these measurements, the anti-scatter grid is removed from the system. The coded aperture component is positioned between the breast and the detector, but not directly relative to the detector as the anti-scatter grid is. The coded aperture absorbs some of the scattered x-rays and allows others to pass through to the detector. Absorption of some of the scattered X-rays creates a unique shadow in the measured scattering data that algorithms (e.g., maximum likelihood estimation) can benefit from, allowing the calculation of the scattered X-ray origin and scattering angle to generate the X-ray scattering spectrum of the volumetric X-ray diffraction image.

[0029] In addition to beam modifying and / or limiting devices, two major factors affect the amount and energy of scattered radiation leaving the patient's tissue: kilovoltage peak (kVp) and the volume of tissue irradiated. The volume of tissue depends on the thickness of the region of interest, the sub-region within the patient that the operator is interested in inspecting, and the x-ray beam field size. Increasing the volume of tissue irradiated results in increased scatter generation. In addition, using a higher kVp increases x-ray penetration and reduces its overall absorption (photoelectric interaction), but a higher kVp increases the percentage of photon interactions (e.g., Compton interactions, Thomson scattering) and the energy of the scattered radiation leaving the patient. Using a higher kVp or increasing the volume of tissue irradiated results in an increase in the scattered radiation reaching the image detector.

[0030] During the performance of a mammogram, one goal is to limit the beam field size to the area of ​​interest. To limit the field size, the X-ray beam is confined to limit the patient's exposure and reduce the amount of scattered radiation generated. For example, an unconfined beam may project beyond the boundaries of the image detector, increasing the patient's exposure. Increasing collimation reduces the volume of tissue irradiated, the amount of scattered radiation generated, the number of photons that strike the patient, and the number of X-ray photons that reach the image detector to generate a latent image. Therefore, to improve radiodensity mammography images by limiting the scattered radiation, the mammography system should include controllable beam modifying and / or limiting devices and / or components. In the case of X-ray scatter measurements according to the present invention, controlling the area of ​​interest of the irradiated tissue through collimation allows less scattering from non-suspicious areas of the tissue to be measured, thus reducing the total intensity of the total scattered radiation field, but on the other hand, there is less multiplexing of scattering from non-suspicious areas of the tissue in the total measured scatter signal, allowing a more useful scatter signal to be measured with less total radiation to the patient.

[0031] To address the above-mentioned problems, in one embodiment, the mammography system described herein includes an X-ray source (X-ray generator), an X-ray tube, a collimator, at least one compression plate, an anti-scatter grid, a coded aperture, and an image detector. The X-ray source is designed to deliver, modulate, and regulate the electrical energy required by the X-ray tube. The X-ray tube is designed to emit, accelerate, and decelerate electrons to generate X-rays. A voltage applied between the electrodes (cathode and anode) accelerates the electrons. The anode material determines the characteristics of the radiation. The X-ray source and the X-ray tube affect the radiation yield, exposure time, and image quality. The collimator controls the shape of the X-ray beam and the subsequent irradiated tissue volume. The compression plate is manually and / or automatically adjustable to change the thickness and pressure of the patient's region of interest. Advantageously, for transmission measurements, proper compression results in less radiation scatter, improved contrast due to less beam hardening, reduced radiation dose, prevention of motion blur, better image geometry, and better tissue separation.

[0032] In one embodiment, the mammography system includes an auxiliary filter disposed in the x-ray beam path to modify the photon spectrum of the primary x-ray beam and optimize radiation quality. For example, without limitation, filter materials include, but are not limited to, molybdenum, rhodium, copper, and aluminum. In another embodiment, the collimator is designed to reduce patient dose, scattered radiation, and exposure to the image receptor while increasing radiographic contrast.

[0033] A general depiction of such an embodiment of a mammography system is shown in FIG. 1. FIG. 1 illustrates a schematic of general components and layout for in vivo breast tissue X-ray transmission and scattering measurements. The mammography system 100 comprises a movable X-ray source 101 for generating an X-ray beam 102 for irradiating a patient's breast 105. The X-ray source 101 may be adjustable based on at least one operating parameter, which may include exposure time, current, voltage, or filtering. The mammography system 100 further comprises a collimator 103 having an aperture with at least one dimension configurable positioned between the X-ray source and the patient's breast to control the shape of the primary X-ray beam 102 and the illuminated tissue volume. The mammography system 100 further comprises a plurality of breast plates 104 for positioning the patient's breast 105. The mammography system 100 further comprises a coded aperture 106. The coded aperture 106 is positioned between the patient's breast 105 and an X-ray detector array 108. In one embodiment, the coded aperture 106 may be integrated into the breast plate 104. The coded aperture 106 is configured to modulate scattered x-ray radiation from the patient's breast 105 detected by the x-ray detector array 108. The x-ray detector array 108 comprises a plurality of x-ray detection elements. The x-ray detector array 108 is movable in at least two dimensions and configurable to be positioned at a measurement location to measure x-ray radiation from the x-ray beam 102. The mammography system 100 may further include an x-ray beam block 107. The beam block 107 may be movable. The beam block 107 may be positioned between the patient's breast 105 and the x-ray detector array 108 in the path of the x-ray beam 102. In one embodiment, the beam block 107 may be integrated into the coded aperture 106. Note that movable and movement are defined here not only as components moving in physical space, but can also be achieved by moving the patient relative to the components (e.g., movement on a platform or bed that can move the patient in 3D space while the system remains stationary).

[0034] Mammography system 100 performs X-ray transmission and X-ray scattering measurements separately and uses different configurations for X-ray transmission versus X-ray scattering measurements. More specifically, mammography system 100 performs an initial X-ray transmission measurement or set of X-ray transmission measurements with data processing to generate a two-dimensional (2D) or three-dimensional (3D) transmission mammogram, as is typical of existing digital mammography methods, as described in more detail below, followed by a subsequent X-ray scattering measurement or set of X-ray scattering measurements to calculate a spatially resolved X-ray scattering spectrum reconstruction and an associated estimate of the tissue type of the irradiated tissue volume in the X-ray scattering measurement. A spatially resolved X-ray scattering spectrum reconstruction is defined herein as a multidimensional data or image that includes an X-ray scattering spectrum within each spatial location, as reconstructed (or calculated) by a reconstruction algorithm (e.g., maximum likelihood estimation). Advantageously, the mammography system 100 identifies regions of interest in the transmission mammogram for performing X-ray scatter measurements and tissue type analysis, which minimizes radiation dose to the patient, improves the speed of the total measurement and analysis process, and facilitates adoption of the method by clinicians compared to methods that perform scatter measurements of the entire breast. Alternatively, or additionally, the mammography system 100 may receive a selection of the region of interest via a user interface. The transmission mammogram data may also be used in conjunction with reconstructed estimates of pixel or voxel scatter spectra to classify tissue.

[0035] The mammography system described herein is designed such that the scattered x-rays pass through a coded aperture such that the intensity of the scattered x-rays is modulated based on the aperture pattern. This results in different magnifications and projections of the shadows in the scatter data. In addition to the spatially dependent intensity modulation, different tissue types have different scatter signatures. The mammography system may measure all illuminated tissue points simultaneously. The raw modulated scatter data is summed from all illuminated tissue points. The measured scatter data may be processed (e.g., background subtraction or Fourier filtering). The mammography system reconstructs the x-ray scatter spectrum in object space, and there is an additional dimension for the scatter data to the number of dimensions of the selected object. This may include reconstructions with three spatial dimensions and a fourth scatter dimension. In such an example, the reconstruction will be composed of 4D pixels, called toxels in some contexts. By way of example and without limitation, using a system of linear equations, the mammography system reconstructs the object space x-ray spectrum data by vectorizing the entire pixelated intensity of the scatter data, and then vectorizing the entire reconstructed spatially resolved object space spectrum map. The mammography system then creates a forward matrix that represents the forward projection of the scattered x-rays from the object vector to the measurement vector. As an example, the detected scatter intensity vector is equal to the forward matrix multiplied by the XRD map vector. The forward matrix may include a spatial model of the coded aperture with attenuation characteristics and locations for each point in the object space and each point in the detector space. The mammography system may further include at least one algorithm for estimating the object space using the measured detector space and the model of the XRD map system. The coded aperture allows for differentiation of the x-ray signal based on location within the breast tissue to accurately estimate the XRD spectrum within each voxel and generate a toxel map.

[0036] FIG. 2 illustrates an exemplary process flow diagram for an embodiment of a method for performing spatially resolved volumetric X-ray scattering tomography mammography described herein. In method 200, a standard mammogram (i.e., X-ray transmission measurement) is first performed (201) to generate a two-dimensional (2D) or three-dimensional (3D) radiodensity mammogram image of the breast. Next, in method 200, a region of interest is selected by a user via a user interface (202). Next, in method 200, a control system configures the mammography system 203 for X-ray scatter measurement of the identified region of interest 204. To configure the mammography system 203, the control system calculates how to move components or change measurement parameters to modulate scattered X-ray radiation from the specified region of interest using a coded aperture and measure the modulated scatter using an X-ray detector array. In some embodiments, this calculation involves optimizing the configuration to minimize radiation dose to the patient or improve the quality, such as signal-to-noise, of the measured X-ray scatter data that is measured. The control system then defines the configuration by moving components or changing measurement parameters to perform an X-ray scatter measurement of the identified region of interest 204. For example, but not by way of limitation, the X-ray scatter measurement involves adjusting the scatter using a coded aperture, so that the mammography system is operable to move other components to the correct relative positions. For example, the collimator may modify the beam size and shape, and the source may be moved to target the region of interest. After the X-ray scatter measurement 204, reconstruction and classification algorithms operate on the collected scatter data 205 to provide estimated tissue characteristics, an example being the likelihood of malignant tissue 206, and generate a spatially resolved scatter mammogram image 206. It should be noted that a spatially resolved scatter mammogram image here may refer to a transmission mammogram image (e.g., 2D, 3D) that includes additional data provided from the scatter measurement.This can be as complex as presenting data from scattering measurements throughout the entire breast in a region of interest, or presenting a summary metric expressed in a non-spatial manner (e.g., maximum probability of cancer, binary cancer / not cancer, across the entire breast).

[0037] For example, but not by way of limitation, in one embodiment, the X-ray source is configured to generate a pencil-shaped beam to perform X-ray scattering measurements and obtain data for areas of interest flagged by the user and / or software of the mammography system. The mammography system determines that the X-ray source can be moved to change the viewpoint of the breast, provide a shorter beam through the tissue, change the type of tissue the beam passes through (e.g., minimize the amount of glandular tissue in the beam path), and generally target the area of ​​interest. Reducing the amount of tissue the X-ray beam passes through will result in less attenuation of the scattered X-ray signal and therefore less radiation dose required for the same signal-to-noise quality of the measured scatter data. Additionally, the collimator can be adjusted to move the pencil-shaped beam from the X-ray source through the area of ​​interest to minimize the beam path. The mammography system can move a beam block to block the direct X-ray beam from reaching the detector. The detector and / or coded aperture may be moved to optimize the x-ray scatter measurement (e.g., capture more signal or a more relevant area of ​​the scattered radiation field in less time). The mammography system may further adjust the x-ray exposure time, amount of current, and / or voltage to optimize the dose and measurement signal-to-noise ratio.

[0038] FIG. 3 illustrates a schematic of the post-acquisition process performed on the measured scatter data to present tissue information, in this example, a match of a suspected target to cancer, to a system operator. To demonstrate the conversion of modulated scatter data into information for the operator, FIG. 3 shows a schematic in which a "Measured Data" panel 301 gives exemplary scatter data with spatially varying intensity modulation due to a coded aperture. A reconstruction algorithm (e.g., maximum likelihood estimation) can be used with a forward model 302 of the measurement scenario to demultiplex the measured modulated scatter signal convolved with the scatter signal associated with each location and the spatial origin of the scatter spectrum, thereby allowing reconstruction of spatially resolved X-ray scatter spectrum information. A "User Display" panel 303 shows an example of how information can be presented to an operator, with window 304 showing a schematic of the measured and reference scatter signatures, as well as a comparison of the cancer with a score or indicator of match between the measured signature and the reference cancer signature. For example, but not by way of limitation, a score or match between the reconstructed X-ray scatter spectrum in a voxel and a reference spectrum of a tissue type may be provided to the user by coloring the 2D or 3D transmission mammogram image, overlaying a text box on the image with a match or score value, overlaying a text box on the image indicating that the match or score value is above a threshold, binary flagging the region of interest as benign versus cancer, and / or providing a continuum of values ​​for each pixel or voxel that informs the user on the region of interest (e.g., correlation with a reference X-ray scatter spectrum of cancerous tissue). For example, but not by way of limitation, a mammography system may display an index or score (e.g., an estimated percentage of cancer likelihood for the voxel and / or region of the voxel).

[0039] Some specific features of the components in these similar embodiments of the system are shown in Figures 4A, 4B, 5A, 5B, 6A, 6B, and 6C. Figures 4A and 4B illustrate how the collimation and subsequently the irradiated tissue volume can be varied within the X-ray source head 400 by opening the collimation 402 or changing the number and location of collimators that shape the beam 404. Figure 4A shows that the X-ray focal spot 401 produces a cone-shaped beam 403 due to open collimation. Figure 4B illustrates how the X-ray focal spot produces a pencil-shaped or fan-shaped beam 405 due to the multi-stage collimation of 402 and 404. This ability to control the irradiated volume of tissue is common among certain embodiments of the methods discussed below. For example, but not by way of limitation, the collimator can be used to switch to a pencil-shaped beam to target a suspected area of ​​interest. This reduces the volume of irradiated tissue compared to open collimation, which reduces the radiation dose to the patient and simplifies the processing and reconstruction of the X-ray scattering data by reducing the overall level of multiplexing in the X-ray scattering data.

[0040] 5A-5B show two exemplary coded apertures that may be used in the embodiments described herein. The coded aperture 501 in FIG. 5A has a central opening 502 that allows the primary pencil beam to pass without interaction. FIG. 5B shows a coded aperture 503 that includes a central slit 504 for the primary fan beam to pass through. This concept may be extended by having a larger central opening for the cone beam when used during X-ray scattering measurements. While the embodiments with an opening within an aperture will be utilized when a beam block is positioned after the coded aperture, these openings may instead be replaced with a beam block built into the aperture in alternative embodiments.

[0041] 6A-6C show how the beam block 608 may be implemented in an embodiment of a mammography system 600 described below. Shown in FIGS. 6A-6C are an X-ray source 601, a primary X-ray beam 602, a collimator 603, a breast plate 604, a tissue region of interest 605 in a patient's breast, scattered X-rays 606, a coded aperture 607, a primary beam block 608, and a detector 609. The utility of beam blocks for X-ray scatter measurements is known to those skilled in the art. The beam block may be separate from the coded aperture, as shown in FIGS. 6A and 6B, or may be located in front of or behind the coded aperture, relative to the tissue location, as shown in FIG. 6C, or may be incorporated into the coded aperture. Such a choice of beam block implementation will be made by considering, among other things, the tradeoff between ease of integration of the beam block into an existing transmission mammography system form factor and the quality of the measured scatter data (i.e., to reduce excess parasitic scatter signal from the coded aperture or other components). Mammography system embodiments having similar beam block configurations may also have the ability to translate or rotate any of these beam block configurations, particularly in embodiments in which the source and collimator may be moved or changed to illuminate specific sub-regions of the breast tissue.

[0042] An embodiment of a mammography system that facilitates the demonstration of a first transmission and a second scatter measurement of an area of ​​interest, or switching between transmission and scatter measurements, is shown in Figures 7A and 7B. For the mammography system 700 shown in Figures 7A and 7B, there is an x-ray source 701, an x-ray cone beam 702, a collimator 703, a breast plate 704, a tissue area of ​​interest 705 in a patient's breast, a coded aperture 706, a primary beam block 707, a detector 708, a component mounting / rotation system 709, a display 710 for acquired results, an x-ray beam 711 for x-ray scatter measurements, and scattered x-rays 712. Figure 7A shows an embodiment of a mammography system in magnification mode, where the breast is positioned with the breast plate 704 at a greater distance from the detector 708 than when measuring in standard or non-magnification mode. In one embodiment of a system having an anti-scatter grid covering the detector for use in non-magnification transmission mode, the anti-scatter grid is retracted. FIG. 7B shows collimation in the X-ray source head shaping the cone beam into a pencil or fan beam, with the collimator 703 moved into the beam path to reduce background scattering. The pencil or fan beam illuminates the suspected region of breast tissue 705. A movable coded aperture 706 is also configured in front of the detector to modulate the intensity of the scattered X-ray radiation reaching the detector, and a movable beam block 707 is also configured in the path of the pencil or fan beam used for the X-ray scattering measurement. The tissue region of interest provided as feedback from the operator is translated by the control software into the location of the collimator and beam block to allow the second measurement to record X-ray scattering only in the suspected region. Alternatively, the tissue region of interest may be automatically flagged by the control software without feedback from the operator. The remainder of the method for processing the scattering data then proceeds as previously described to reconstruct the X-ray scattering spectrum of the specified volume and provide the operator with a spatially resolved estimate of the cancer probability in the specified sub-region 710.This embodiment minimizes the dose received by the patient compared to performing both full volume transmission and full volume diffraction measurements, although full volume diffraction measurements without operator-specified sub-regions may be performed as well.

[0043] A similar embodiment of a mammography system to that shown in Figures 7A and 7B is shown in Figures 8A and 8B, including a coded aperture 806 that rotates into position for X-ray scatter measurements, as opposed to translating, and may be easier to integrate into existing transmission-based mammography unit form factors. For the mammography system 800 shown in Figures 8A and 8B, there is an X-ray source 801, an X-ray cone beam 802, a collimator 803, a breast plate 804, a tissue region of interest 805 in a patient's breast, a coded aperture 806, a primary beam block 807, a detector 808, a component mounting / rotation system 809, a display 810 for the acquired results, an X-ray beam 811 for X-ray scatter measurements, and scattered X-rays 812.

[0044] Another similar embodiment includes separate detectors for transmission and diffraction measurements and is shown in Figures 9A and 9B. For the mammography system 900 shown in Figures 9A and 9B, there is an x-ray source 901, an x-ray cone beam 902, a collimator 903, a breast plate 904, a tissue region of interest 905 in a patient's breast, an x-ray transmission detector 906, a coded aperture 907, a primary beam block 908, an x-ray scatter detector 909, a component mounting / rotation system 910, a display 911 for acquired results, an x-ray beam 912 for x-ray scatter measurements, and scattered x-rays 913. In this case, when a transmission measurement is made, the transmission detector 906 translates or rotates to reveal the coded aperture 907, the scatter detector 909, and the beam block 908, while the components move to define a pencil or fan beam of a user selected region in the same manner as the embodiments of Figures 7A, 7B, 8A, and 8B.

[0045] The mammography system embodiments described in the preceding paragraphs and shown in Figures 7A-9C are non-exhaustive examples of those that may be most easily implemented into existing mammography system form factors. Figures 10A-10D demonstrate more specific X-ray detector arrangements for similar mammography systems within that class of embodiments, including a single X-ray detector, multiple X-ray detectors, arrangements with multiple X-ray detectors at various locations and / or orientations (effectively performing a 3D arrangement of pixels), as well as arrangements with several measurement mode specific detectors (e.g., multiple detectors, some of which are solely for X-ray scatter measurements). In Figures 10A-10D, a primary X-ray detector 1001 may be used by itself or in combination with any number of additional X-ray detectors (here, 1002 and 1003) in various configurations.

[0046] Another embodiment of a mammography system is shown in Figure 11. For the mammography system 1100 shown in Figure 11, there is a transmission x-ray source 1101, an x-ray cone beam 1102, a breast compression paddle 1103, a tissue region of interest in a patient's breast 1104, an x-ray transmission detector 1105, a scattered x-ray source 1106, a pencil / fan beam 1107, a collimator 1108, an x-ray scatterer 1109, a coded aperture 1110, a primary beam block 1111, and an x-ray scatter detector 1112. In this embodiment, there are two sources, one for performing the transmission measurement 1105 and one for performing the x-ray scatter measurement 1112. In this embodiment, the source used for the x-ray scatter measurement 1106, along with the associated collimator 1108, coded aperture 1110, beam block 1111, and detector 1112, can rotate to allow both multiple views of the same region of interest, which can be a user-specified sub-region or the entire volume. Embodiments of methods for using such mammography systems provide advantages such as enabling optimization of the geometry for a given specified sub-region, e.g., shortening the path length from a suspicious mass to the exterior of the breast in the low-angle forward scatter regime to reduce self-attenuation of the scatter signal within the breast tissue, minimizing dose to the patient, or improving the expected scatter reconstruction quality based on the detector coverage or distance and the relative orientation of the coded aperture and expected scatter to the detector.

[0047] Another embodiment of a mammography system that allows for various viewpoints on breast tissue for X-ray scatter measurement(s) is shown in Figures 12A and 12B. For the mammography system 1200 shown in Figures 12A and 12B, there is an x-ray source 1201, an x-ray cone beam 1202, a breast compression paddle 1203, a tissue region of interest in a patient's breast 1204, an x-ray transmission detector 1205, a collimator 1206, a coded aperture 1207, a primary beam block 1208, an x-ray scatter detector 1209, a pencil / fan beam 1210, and an x-ray scatterer 1211. In this embodiment, instead of having a second x-ray source for the x-ray scatter measurement, the source used for the x-ray transmission measurement 1201 can be rotated to a position that provides a significantly different perspective on the volume, effectively serving the purpose of the scatter source from the embodiment shown in Figure 11. This embodiment is advantageous in reducing component and maintenance costs while increasing system reliability by having fewer x-ray sources, which are typically the components with the shortest life spans and most likely points of failure in an x-ray system.

[0048] Figure 13 illustrates a mammography system with a removable coded aperture similar to the mammography system illustrated in Figure 7. The coded aperture is mounted between the patient's breast and the x-ray detector for x-ray scatter measurements. For the system 1300 shown in Figure 13, there is an x-ray source 1301 with an x-ray beam not shown, a collimator 1302, a breast compression paddle 1303, a tissue region of interest 1304 in the patient's breast, a coded aperture 1305 with a mechanism 1306 for attaching (e.g., clipping) to the device via device components, an x-ray detector 1307, and a body 1308 of the system. Another similar embodiment includes combining the coded aperture with a magnified spacer table that sits on the detector. 14, there is an x-ray source 1401 with an x-ray beam, not shown, a collimator 1402, an upper breast compression paddle 1403, a tissue region of interest 1404 within the patient's breast, a magnification spacer table 1405 that rests or locks onto the x-ray detector, a coded aperture 1406 that is temporarily or permanently associated with the magnification spacer table, an x-ray detector 1407, and a body of the system 1408. This embodiment reflects an alternative method for magnification mode imaging that utilizes a raised platform on the detector with a coded aperture attached or integrated into the platform between the top of the platform on which the patient's breast is positioned and the x-ray detector.

[0049] FIG. 15 presents an exemplary representation of a portion of an X-ray scattering spectrum reconstruction. Shown in FIG. 15 is a 2D or 3D X-ray densitometric mammogram image 1501 generated from the transmission data, the region where the X-ray scattering measurements are made marked between dashed lines 1502, and diffraction measurements that may be identified for any tissue region of interest 1503 that may be used to distinguish between fat, cancer, and glandular tissue. The spatially resolved reconstructed X-ray scattering spectrum 1503 provides additional contrast for tissue differentiation. In a typical operation of the system, such as by a technician or clinician, the reconstructed X-ray scattering spectrum is not accessible by the operator, but this data will be used to generate visualizations that are useful to the technician or clinician, such as the percent match to a reference spectrum of a particular tissue type, including healthy or cancerous tissue types, as shown in FIG. 3.

[0050] Another approach to using X-ray scattering reconstruction to add clinically relevant visual contrast to standard X-ray densitometric mammograms generated from X-ray transmission measurements is shown in FIG. 16. In FIG. 16, a 2D or 3D standard mammogram image 1601, areas where X-ray scattering measurements are made marked between dashed lines 1602, and a color scale 1603 represented as different hatching patterns are shown. A color spectrum will be generated based on the X-ray scattering spectrum reconstruction. A specific example is transitioning between colors such as blue, yellow, and red for areas of X-ray scattering measurements with lower mean scattering angles 1604, areas of X-ray scattering measurements with higher mean scattering angles 1605, and areas of X-ray scattering measurements with intermediate mean scattering angles 1606, represented in FIG. 16 by both horizontal, vertical and horizontal, and only vertical hatching patterns, respectively, and the determination of lower, higher, or intermediate mean scattering angles correlates with dominant features or peaks in the reference spectra of a particular healthy or cancerous tissue type. Other embodiments may utilize other calculated values ​​from the x-ray scatter spectrum reconstruction to generate a color map that adds additional contrast between tissue types.

[0051] The mammography system described herein further includes controllable electronics. In one embodiment, the mammography device includes components such as a processor, a system memory having random access memory (RAM) and read only memory (ROM), an I2C sensor, and a system bus coupling the memory to the processor. The processor manages the overall operation of the mammography system. The processor is any controller, microcontroller, or microprocessor capable of processing program instructions. In one embodiment, the control electronics includes at least one antenna that enables the mammography system to transmit information to and / or receive information from at least one remote device. The at least one antenna provides standard-based or non-standard-based wireless communication, including but not limited to radio frequency (RF), Wi-Fi, Bluetooth, Zigbee, near field communication (NFC), 3G, 4G, and / or 5G cellular, or other similar communication methods.

[0052] As a further example, a processor may be a general-purpose microprocessor (e.g., a central processing unit (CPU)), a graphics processing unit (GPU), a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic device (PLD), a controller, a state machine, gate or transistor logic, discrete hardware components, or any other suitable entity or combination capable of performing calculations, processing instructions for execution, and / or other information manipulation.

[0053] The mammography system described herein is operable to analyze the image data to determine whether to modify the X-ray beam and the positioning of components of the mammography device. For example, but not by way of limitation, the at least one processor is designed to control the cross-sectional shape, divergence, and spatial extent of the initial X-ray beam(s) and one or more filters located between the X-ray source(s) and the breast tissue to modify the energy spectrum and irradiance of the X-ray beam(s) reaching the breast tissue. Advantageously, if the at least one processor detects that the image data has poor quality, the at least one processor is operable to send a command to the X-ray source to modify at least one of the shape, divergence, spatial extent, and / or intensity based on the quality.

[0054] Yet another advantage of the mammography systems described herein is the ability to classify tissue based on image data (e.g., scatter data). Using a modulated coded aperture, the mammography systems described herein are operable to receive image data corresponding to a patient's breast and classify breast tissue.

[0055] The mammography systems described herein are further operable to analyze the X-ray transmission data, determine tissue type (e.g., fatty, normal, fibroglandular, cancerous), and optimize delivered power, system efficiency, signal-to-noise ratio, scatter angle, momentum transfer. Advantageously, the mammography systems described herein are operable to identify healthy tissue margins based on the transmission image data, and generate at least one recommendation based on the transmission image data. For example, but not limited to, the at least one recommendation includes identifying a region of interest to be removed. Another example includes a recommendation to modify and / or replace the coded aperture if the signal-to-noise ratio and / or the received transmission data is insufficient.

[0056] In one embodiment, the mammography system described herein includes at least one algorithm designed to analyze the received image data to determine at least one tissue characteristic (e.g., tissue classification). For example, but not by way of limitation, the at least one algorithm includes a deblurring algorithm. In yet another embodiment, the at least one algorithm includes a machine learning algorithm. For example, but not by way of limitation, the machine learning algorithm includes a supervised learning algorithm (e.g., classification), a semi-supervised learning algorithm, an unsupervised learning algorithm, and / or a reinforcement learning algorithm. In yet another example, the machine learning algorithm includes a naive Bayes algorithm, a K-means clustering algorithm, a support vector machine (SVM) algorithm, a linear regression algorithm, a logistic regression algorithm, an artificial neural network, a decision tree, a random forest, a K-nearest neighbor algorithm, a gradient boosting algorithm, and / or a dimensionality reduction algorithm.

[0057] There are several commonalities among the mammography system and method embodiments described above that, when implemented, provide important advantages. One such commonality is the components used in both the X-ray transmission and X-ray scatter measurements. This allows for lower total system costs, reduced chance of component failure, and the potential for shorter overall measurement times. Another commonality is the ability of key components (e.g., X-ray source, collimator, coded aperture, and X-ray detector) to rotate or translate. This allows for potential cost savings; specific combinations of components used in one measurement mode (e.g., X-ray scatter measurement or X-ray transmission measurement) and not the other, or used in both measurement modes; directing the X-ray source and accompanying X-ray scatter measurement components (e.g., pencil or fan beam collimators, coded apertures, beam blocks, detectors) to reduce patient dose or to measure specific sub-regions of tissue that can be used to optimize reconstruction performance; measurements from multiple viewpoints in either X-ray transmission mode or X-ray scatter mode that can also be used to optimize performance; and implementation of embodiments of the system described herein that are easily integrated into existing transmission-based mammography systems.

[0058] Further specific aspects of potential embodiments of the general method may provide further advantages. One such specification is that the transmission and scattering measurements are performed synchronously over the same period of time, which may shorten the measurement time and potentially reduce the dose to the patient if the same beam is used synchronously for the scattering and transmission measurements. The key components of the general system are common knowledge to those trained in the art and may be varied with obvious associated advantages in their implementation. These variations include, but are not limited to, variations in the type of X-ray source (e.g., X-ray generator vs. radioisotope, generator anode material, generator focal spot size), variations in the type of X-ray detector (energy integration, stacked multi-energy channels, and energy discrimination or photon counting), variations in the coded aperture pattern type (e.g., periodic, Fresnel zone plate, random or optimized random, uniform redundant array), material, or thickness. Multiple coded apertures may also be used in combination or by themselves to modulate the detected scattering signal, the selection of which may be automatically controlled taking into account the measurement conditions, e.g., the geometric constraints of measuring scattering from a user-specified sub-region of the tissue. Existing mammography systems use digital pixelated area x-ray detectors to measure x-ray transmission images of a patient's breast. These include scintillator detectors, such as those using cesium iodide scintillators, or direct conversion detectors, such as those using amorphous selenium. While one of these commonly used energy-integrating x-ray transmission detectors would be sufficient for the present invention, detection of scattered x-rays with an energy-differential or photon-counting detector may provide improved signal-to-noise ratio, dose reduction to the patient, and overall performance of the system. For scatter measurements, there are obvious advantages to those skilled in the art for embodiments having curved or staggered area configurations of pixels or detector elements. While Figures 9A, 9B, 11, 12A, and 12B show embodiments that use multiple detectors and may allow these different types of x-ray detectors to be implemented, Figure 10 demonstrates an exemplary arrangement in which multiple detectors (of potentially varying types) may be oriented in a general area to detect transmitted and scattered x-rays.

[0059] In one embodiment, a spatially resolved volumetric x-ray scattering tomography mammography system is disclosed. The mammography system includes a movable x-ray source for generating a primary x-ray beam for irradiating a patient's breast. The x-ray source is adjustable based on at least one operating parameter including exposure time, current, voltage, or filtering. The mammography system further includes a collimator positioned between the x-ray source and the patient's breast. The collimator includes an aperture that is configurable in at least one dimension to shape the primary x-ray beam. The mammography system further includes a plurality of movable breast plates operable to position the patient's breast in a path of the primary x-ray beam. The mammography system further includes an x-ray detector array including a plurality of x-ray detection elements. At least a portion of the x-ray detection elements are movable. The x-ray detector array is configurable to position at least one x-ray detection element distal to the x-ray source at a first measurement location in a path of the primary x-ray beam passing through the patient's breast to measure transmitted x-ray radiation from the primary x-ray beam. The X-ray detector array can be configured to position at least one X-ray detector element distal to the X-ray source at a second measurement location outside the path of the primary X-ray beam passing through the patient's breast to measure scattered X-ray radiation from the primary X-ray beam. The mammography system further includes a coded aperture positioned distal to the X-ray source between the patient's breast and the X-ray detector array. The coded aperture is configured to modulate scattered X-ray radiation from the patient's breast detected by the X-ray detector array. The mammography system can be configured to perform X-ray scatter measurements and X-ray transmission measurements. When performing X-ray scatter measurements, the X-ray detector array is configured such that at least one X-ray detector element is positioned outside the path of the primary X-ray beam to detect scattered X-ray radiation from the primary X-ray beam passing through the patient's breast. When performing X-ray transmission measurements, the X-ray detector array is configured such that at least one X-ray detector element is positioned within the path of the primary X-ray beam to detect X-ray radiation transmitted through the patient's breast. The mammography system further includes a control system comprising a memory and a processor.The processor of the mammography system is configured to configure the mammography system for X-ray transmission or X-ray scatter measurements. Configuring the mammography system includes controlling at least one configuration parameter including a position of the X-ray source, a position of the X-ray detector array, a size of an opening of a collimator, at least one operating parameter of the X-ray source, or at least one position of the breast plate.

[0060] For the X-ray transmission measurements, the processor of the mammography system is further configured to receive X-ray transmission data representative of transmitted X-ray radiation detected by the multiple X-ray detection elements of the X-ray detector array. The processor of the mammography system is further configured to generate an X-ray density mammogram image based on the received X-ray transmission data. The processor of the mammography system is further configured to identify a region of interest in the patient's breast based on the X-ray density mammogram image. The processor of the mammography system is further configured to determine at least one scatter configuration parameter for the X-ray scatter measurements based on the identified region of interest of the patient's breast. The processor of the mammography system is further configured to configure the mammography system for the X-ray scatter measurements based on the determined at least one scatter configuration parameter.

[0061] For X-ray scatter measurements, the processor of the mammography system is further configured to receive X-ray scatter data representative of scattered X-ray radiation for the region of interest detected by the multiple X-ray detection elements of the X-ray detector array. The processor of the mammography system is further configured to estimate a spatially resolved X-ray scatter spectrum reconstruction based on the received X-ray scatter data, the received X-ray transmission data, and at least one scatter configuration parameter. The processor of the mammography system is further configured to determine spatially resolved tissue properties based on the received X-ray scatter data for the region of interest. The processor of the mammography system is further configured to generate a spatially resolved scatter mammogram image based on the received X-ray transmission data and the received X-ray scatter data.

[0062] In one embodiment of the mammography system described herein, for X-ray scatter measurements, the coded aperture is operable to move between the patient's breast and the multiple X-ray detection elements to a position distal from the X-ray source to modulate detected scattered X-ray radiation. For X-ray transmission measurements, the patient's breast is positioned at a first distance from the X-ray detector array. For X-ray scatter measurements, the system may be further operable in a magnified mode. In the magnified mode, the patient's breast is positioned at a second distance from the X-ray detector array. The second distance is greater than the first distance. The processor may be further configured to determine coded aperture configuration parameters including a position of the coded aperture during X-ray scatter measurements of an identified region of interest in the patient's breast. The processor may be further configured to control the position of the coded aperture based on the determined coded aperture configuration parameters.

[0063] In one embodiment of the mammography system described herein, the mammography system may further include a beam block configured to block the primary x-ray beam during x-ray scatter measurements. The beam block is positioned between the patient's breast and the x-ray detector array in the path of the primary x-ray beam. The beam block may be movable and controllable by a processor, which may be further configured to determine beam block configuration parameters including a position of the beam block during x-ray scatter measurements of an identified region of interest in the patient's breast. The processor may be further configured to control the position of the beam block based on the determined beam block configuration parameters.

[0064] In one embodiment of the mammography system described herein, the mammography system may further include an additional X-ray source, where the X-ray source is configured for X-ray transmission measurements and the additional X-ray source is configured for X-ray scatter measurements.

[0065] In one embodiment of the mammography system described herein, the at least one spatially resolved tissue characteristic includes a tissue type indicative of cancerous or benign tissue. The spatially resolved scatter mammogram image includes at least one indication based on the spatially resolved X-ray scatter spectrum reconstruction. The at least one indication indicates whether the region of interest contains benign or cancerous tissue.

[0066] In one embodiment of the mammography system described herein, the processor may be further configured to generate a coloring of the spatially resolved scatter mammogram image generated based on the received X-ray transmission data and the received X-ray scatter data, the coloring being based on a spatially resolved X-ray scatter spectrum reconstruction.

[0067] In one embodiment of the mammography system described herein, the processor may be further configured to calculate a spatially resolved estimate of a momentum transfer spectrum of the breast of the region of interest from the received x-ray scattering data. The processor may be further configured to use the spatially resolved estimate of the momentum transfer spectrum in determining the spatially resolved tissue properties. The memory may include a reference library of a plurality of pre-existing tissue momentum transfer spectra. The processor may be further configured to determine the spatially resolved tissue properties using the reference library of pre-existing tissue momentum transfer spectra in combination with the calculated spatially resolved estimate of the momentum transfer spectrum of the region of interest. The processor may be further configured to use a classification algorithm in determining the spatially resolved tissue properties. The processor may be further configured to use a machine learning algorithm in calculating the spatially resolved estimate of the spatially resolved tissue properties. The processor may be further configured to use a rule-based classification algorithm in calculating the spatially resolved estimate of the spatially resolved tissue properties.

[0068] In one embodiment of the mammography system described herein, at least one of the X-ray detection elements is used for both X-ray transmission and X-ray scatter measurements.

[0069] In one embodiment of the mammography system described herein, the processor is further configured to vary the position of the x-ray source to control the angle of incidence of the primary x-ray beam relative to the patient's breast.

[0070] In one embodiment of the mammography system described herein, at least one operating parameter of the X-ray source is configurable to control the irradiance and energy spectrum of the primary X-ray beam.

[0071] In one embodiment of the mammography system described herein, for the X-ray scatter measurement, at least one of the X-ray detection elements can be configured to detect X-ray radiation from the primary X-ray beam that has been directly transmitted through the patient's breast. The processor can be further configured to receive X-ray transmission data detected by the X-ray detection elements configured to detect X-ray radiation from the primary X-ray beam that has been directly transmitted through the patient's breast. The received X-ray transmission data represents transmitted X-ray radiation detected during the X-ray scatter measurement. An estimation of a spatially resolved X-ray scatter spectrum reconstruction is further based on the received X-ray transmission data detected during the X-ray scatter measurement.

[0072] In one embodiment of the mammography system described herein, the processor is further configured to estimate a radiation dose to the patient during the X-ray scatter measurement and determine at least one scatter configuration parameter for the X-ray scatter measurement based on the estimated radiation dose to the patient.

[0073] In one embodiment, a method for performing spatially resolved volumetric X-ray diffraction tomography mammography is disclosed. The method includes performing an X-ray transmission measurement. The X-ray transmission measurement is performed by transmitting a first primary X-ray beam from an X-ray source through a collimator having an aperture configurable in at least one dimension to shape the first primary X-ray beam, and through a patient's breast positioned between a plurality of breast plates. The X-ray source is adjustable based on at least one operating parameter including exposure time, current, voltage, and / or filtering. The X-ray transmission measurement is further performed by detecting X-ray radiation from the first primary X-ray beam that has directly transmitted through the patient's breast using a plurality of X-ray detection elements of an X-ray detector array. At least some of the X-ray detection elements are movable. The X-ray transmission measurement is further performed by receiving X-ray transmission data from the plurality of X-ray detection elements via a control system including a processor and a memory. The X-ray transmission data represents detected X-ray radiation from the first primary X-ray beam after the first primary X-ray beam has passed through the collimator and the patient's breast. The X-ray transmission measurement is further performed by generating a radiodensity mammogram image of the patient's breast based on the received X-ray transmission data. For example, and without limitation, the radiodensity mammogram image is two-dimensional or three-dimensional. The method further includes identifying an area of ​​interest in the patient's breast based on the radiodensity mammogram image. The method further includes determining scatter measurement configuration parameters for an X-ray scatter measurement of the identified area of ​​interest in the patient's breast. The scatter measurement configuration parameters include a position of the X-ray source, a position of the multiple X-ray detection elements, a size of an opening of the collimator, an X-ray source operating parameter, and / or a position of at least one of the multiple breast plates. The method further includes performing an X-ray scatter measurement of the area of ​​interest. The X-ray scatter measurement is performed by transmitting a second primary X-ray beam from the X-ray source through a collimator and through the patient's breast positioned with the multiple breast plates to shape the second primary X-ray beam.X-ray scatter measurement of the region of interest is further performed by modulating scattered X-ray radiation from the second primary X-ray beam interacting with the patient's breast using a coded aperture positioned between the patient's breast and the multiple X-ray detection elements. X-ray scatter measurement of the region of interest is further performed by detecting the modulated scattered X-ray radiation using the multiple X-ray detection elements. X-ray scatter measurement of the region of interest is further performed by receiving X-ray scatter data representative of the detected scattered X-ray radiation from the multiple X-ray detection elements. X-ray scatter measurement of the region of interest is further performed by calculating a spatially resolved X-ray scatter spectrum reconstruction based on the received X-ray scatter data, the received X-ray transmission data, and the determined scatter measurement configuration parameters. X-ray scatter measurement of the region of interest is further performed by determining at least one spatially resolved tissue property based on the received X-ray scatter data of the region of interest. X-ray scatter measurement of the region of interest is further performed by generating a spatially resolved scatter mammogram image based on the received X-ray transmission data and the received X-ray scatter data.

[0074] In one embodiment of the method for performing spatially resolved volumetric X-ray diffraction tomography mammography, the coded aperture is moved to a position distal from the X-ray source between the patient's breast and the plurality of X-ray detection elements to modulate detected scattered X-ray radiation from the second primary X-ray beam during X-ray scattering measurements. A magnified mode is used in which the patient's breast is positioned at a first distance from the plurality of X-ray detection elements when performing the X-ray transmission measurements and the patient's breast is positioned at a second distance from the plurality of X-ray detection elements when performing the X-ray scattering measurements. The second distance is greater than the first distance. The method may further include determining, via the processor, a coded aperture configuration parameter indicative of a position of the coded aperture during X-ray scattering measurements of an identified region of interest in the patient's breast and controlling, via the processor, the position of the coded aperture.

[0075] In one embodiment of the method for performing spatially resolved volumetric X-ray diffraction tomography mammography, the method may further include blocking the second primary X-rays during the X-ray scatter measurement with a beam block positioned in a path of the second primary X-ray beam between the patient's breast and the multiple X-ray detection elements. The beam block is movable and positioned in a path of the second primary X-ray beam between the patient's breast and the X-ray detection elements when performing the X-ray scatter measurement. The method may further include determining, via the processor, a beam block configuration parameter indicative of a position of the beam block during the X-ray scatter measurement of the identified region of interest, and controlling, via the processor, a position of the beam block based on the determined beam block configuration parameter.

[0076] In one embodiment of a method for performing spatially resolved volumetric x-ray diffraction tomography mammography, an x-ray source is used for x-ray transmission measurements and an additional x-ray source is used for x-ray scattering measurements.

[0077] In one embodiment of the method for performing spatially resolved volumetric X-ray diffraction tomography mammography, the at least one spatially resolved tissue characteristic includes a tissue type indicative of cancerous or benign tissue. The spatially resolved scatter mammogram image includes at least one indication based on the spatially resolved X-ray scatter spectrum reconstruction. The at least one indication indicates whether the identified region of interest contains benign or cancerous tissue.

[0078] In one embodiment of the method for performing spatially resolved volumetric x-ray diffraction tomography mammography, the method further includes generating a spatially resolved scatter mammogram image coloration based on the received x-ray transmission data and the received x-ray scatter data, the coloration being determined based on a spatially resolved x-ray scatter spectrum reconstruction.

[0079] In one embodiment of the method of performing spatially resolved volumetric X-ray diffraction tomography mammography, the method further comprises calculating a spatially resolved estimate of a momentum transfer spectrum of the region of interest from the received X-ray scattering data. The method further comprises using the spatially resolved estimate of the momentum transfer spectrum in determining the at least one spatially resolved tissue property. The method may further comprise determining the at least one spatially resolved tissue property using a reference library of a plurality of pre-existing tissue momentum transfer spectra in combination with the calculated spatially resolved estimate of the momentum transfer spectrum of the region of interest. The method may further comprise using a classification algorithm when determining the at least one spatially resolved tissue property. The method may further comprise using a machine learning algorithm in calculating the spatially resolved estimate of the at least one spatially resolved tissue property. The method may further comprise using a rule-based classification algorithm in calculating the spatially resolved estimate of the at least one spatially resolved tissue property.

[0080] In one embodiment of the method for performing spatially resolved volumetric x-ray diffraction tomography mammography, the method further includes using at least one x-ray detection element for both x-ray transmission measurements and x-ray scattering measurements.

[0081] In one embodiment of the method for performing spatially resolved volumetric x-ray diffraction tomography mammography, the method further includes controlling a position of the x-ray source to control an angle of incidence of the first primary x-ray beam or the second primary x-ray beam relative to the patient's breast.

[0082] In one embodiment of the method for performing spatially resolved volumetric X-ray diffraction tomography mammography, the method further includes configuring at least one operating parameter of the X-ray source to control the irradiance and energy spectrum of the first primary X-ray beam or the second primary X-ray beam.

[0083] In one embodiment of the method for performing spatially resolved volumetric x-ray diffraction tomography mammography, the method further includes receiving x-ray transmission data detected by x-ray detection elements configured to detect x-ray radiation from the second primary x-ray beam that has been directly transmitted through the patient's breast for the x-ray scatter measurement. The received x-ray transmission data represents the transmitted x-ray radiation detected during the x-ray scatter measurement. Calculation of the spatially resolved x-ray scatter spectrum reconstruction is further based on the received x-ray transmission data detected during the x-ray scatter measurement. The at least one x-ray detection element can be configured to detect x-ray radiation from the second primary x-ray beam that has been directly transmitted through the patient's breast.

[0084] In one embodiment of the method for performing spatially resolved volumetric x-ray diffraction tomography mammography, the method further includes estimating a radiation dose to the patient for the x-ray scatter measurement and determining at least one scattering configuration parameter for the x-ray scatter measurement based on the estimated radiation dose to the patient.

[0085] Any combination of one or more computer readable media may be utilized with the mammography system described herein. The computer readable medium may be a computer readable signal medium or a computer readable storage medium (including, but not limited to, a non-transitory computer readable storage medium). The computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination thereof. More specific examples (non-exhaustive list) of computer readable storage media include an electrical connection with one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read only memory (ROM), an erasable programmable read only memory (EPROM or flash memory), an optical fiber, a portable compact disk read only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the context of this document, a computer readable storage medium may be any tangible medium of expression that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0086] A computer-readable signal medium may include a propagated data signal having computer-readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electromagnetic, optical, or any suitable combination thereof. A computer-readable signal medium is not a computer-readable storage medium and may be any computer-readable medium that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

[0087] In one or more exemplary aspects, the instructions may be implemented in hardware, software, firmware, or any combination thereof. A computer-readable medium may provide volatile or non-volatile storage for one or more sets of instructions, such as an operating system, data structures, program modules, applications, or other data that embody any one or more of the methodologies or functions described herein. A computer-readable medium may include a memory, a processor, and / or a storage medium, and may be a single medium or multiple media (e.g., a centralized or distributed computer system) that stores one or more sets of instructions. A non-transitory computer-readable medium includes all computer-readable media, with the only exception being the transitory, propagating signal itself. The instructions may further be transmitted or received over a network via a network interface unit as a communication medium, which may include a modulated data signal, such as a carrier wave or other transport mechanism, and may include any distribution medium. The term "modulated data signal" means a signal that has one or more of its characteristics changed or set in such a manner as to encode information within the signal.

[0088] In the following claims, the corresponding structure, material, acts, and equivalents of all means-plus-function or step-plus-function elements are intended to include any structure, material, or act for performing that function in combination with other specifically claimed elements. The description of the mammography system described herein has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the invention in the disclosed form. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The present embodiment has been chosen and described in order to best explain the principles and practical application of the invention and to enable others skilled in the art to understand the invention in various embodiments with various modifications as suited to the particular use contemplated.

[0089] The description of various embodiments of the mammography system described herein has been presented for purposes of illustration, but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terms used herein have been selected to best express the principles of the embodiments, practical applications or technical improvements to technology found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

Claims

1. 1. A spatially resolved volumetric x-ray scattering tomography mammography system, the mammography system comprising: an x-ray source for generating a primary x-ray beam for irradiating the patient's breast; a collimator positioned between the x-ray source and the breast of the patient; a plurality of movable breast plates operable to position the breasts of the patient within the path of the primary x-ray beam; An X-ray detector array including a plurality of X-ray detecting elements, at least some of the plurality of X-ray detecting elements being movable, the X-ray detector array comprising: positioning at least one x-ray detecting element distal to the x-ray source at a first measurement location within the path of the primary x-ray beam passing through the breast of the patient to measure transmitted x-ray radiation from the primary x-ray beam; an x-ray detector array configurable to: position at least one x-ray detecting element distal to the x-ray source at a second measurement location outside the path of the primary x-ray beam passing through the breast of the patient to measure scattered x-ray radiation from the primary x-ray beam; a coded aperture positioned distal to the x-ray source between the patient's breast and the x-ray detector array, the coded aperture configured to modulate scattered x-ray radiation from the patient's breast detected by the x-ray detector array; a control system comprising a memory and a processor, the processor: controlling at least one configuration parameter including a position of the x-ray source, a position of the x-ray detector array, a size of an opening of the collimator, at least one operating parameter of the x-ray source, or a position of at least one of the movable breast plate; generating an x-ray densitometric mammogram image based on the received x-ray transmission data; identifying a region of interest within the patient's breast based on the x-ray density mammogram image; determining at least one scattering configuration parameter for the X-ray scattering measurement based on the identified region of interest of the breast of the patient; configuring the mammography system for the X-ray scatter measurement based on the determined at least one scatter configuration parameter; receiving x-ray scatter data representing scattered x-ray radiation for the region of interest detected by the plurality of x-ray detecting elements of the x-ray detector array; estimating a spatially resolved x-ray scatter spectral reconstruction based on the received x-ray scatter data, the received x-ray transmission data, and the at least one scatter configuration parameter; determining spatially resolved tissue properties based on the received X-ray scattering data of the region of interest; A mammography system, wherein the mammography system is configurable to perform X-ray scatter measurements and X-ray transmission measurements.

2. 2. The mammography system of claim 1, wherein for the X-ray scatter measurement, the coded aperture is operable to move to a position distal from the X-ray source between the patient's breast and the plurality of X-ray detection elements to modulate the detected scattered X-ray radiation.

3. 3. The mammography system of claim 2, wherein for the X-ray transmission measurement, the patient's breast is positioned at a first distance from the X-ray detector array, and for the X-ray scatter measurement, the mammography system is further operable in a magnification mode, in which the patient's breast is positioned at a second distance from the X-ray detector array, the second distance being greater than the first distance.

4. the processor: determining coded aperture configuration parameters including a position of the coded aperture during the x-ray scatter measurement of the identified region of interest within the breast of the patient; 3. The mammography system of claim 2, further configured to: control the position of the coded aperture based on the determined coded aperture configuration parameters.

5. 10. The mammography system of claim 1, further comprising a beam block configured to block the primary x-ray beam during the x-ray scatter measurement, the beam block being positioned in the path of the primary x-ray beam between the breast of the patient and the x-ray detector array.

6. The beam block is movable and controllable by the processor, and the processor: determining beam block configuration parameters including a position of the beam block during the x-ray scatter measurement of the identified region of interest within the breast of the patient; 6. The mammography system of claim 5, further configured to: control the position of the beam block based on the determined beam block configuration parameters.

7. A mammography system as described in claim 1, further comprising a second X-ray source, the X-ray source configured for the X-ray transmission measurement, and the second X-ray source configured for the X-ray scattering measurement.

8. The mammography system of claim 1 , wherein the spatially resolved tissue characteristics comprise a tissue type indicative of cancerous or benign tissue.

9. the processor: calculating a spatially resolved estimate of a momentum transfer spectrum of the region of interest from the received x-ray scattering data; The mammography system of claim 1 , further configured to perform the spatially resolved tissue property determination using the spatially resolved estimate of the momentum transfer spectrum of the region of interest.

10. The processor is configured to determine the spatially resolved tissue properties using a reference library of a plurality of existing tissue momentum transfer spectra in combination with the spatially resolved estimate of the momentum transfer spectrum of the region of interest; the reference library of the plurality of existing tissue momentum transfer spectra is stored in a memory; 10. The mammography system of claim 9.

11. the processor is further configured to determine the spatially resolved tissue characteristics using a classification algorithm; The mammography system of claim 9 , wherein the classification algorithm is a machine learning algorithm or a rule-based classification algorithm.

12. The mammography system of claim 1 , wherein at least one of the X-ray detection elements is used for both the X-ray transmission measurement and the X-ray scatter measurement.

13. The mammography system of claim 1 , wherein the processor is further configured to vary the position of the x-ray source to control an angle of incidence of the primary x-ray beam with respect to the breast of the patient.

14. The mammography system of claim 1 , wherein the at least one operating parameter of the x-ray source is configurable to control the irradiance and energy spectrum of the primary x-ray beam.

15. For the X-ray scattering measurement, at least one of the x-ray detection elements may be configured to detect x-ray radiation from the primary x-ray beam that has passed directly through the breast of the patient; the processor is further configured to receive x-ray transmission data detected by the x-ray detection element configured to detect x-ray radiation from the primary x-ray beam that has directly transmitted through the breast of the patient, the received x-ray transmission data representing the transmitted x-ray radiation detected during the x-ray scatter measurement; The mammography system of claim 1 , wherein the estimation of the spatially resolved x-ray scatter spectrum reconstruction is further based on the received x-ray transmission data detected during the x-ray scatter measurement.

16. the processor: estimating a radiation dose to the patient during the X-ray scatter measurement; and 10. The mammography system of claim 1, further configured to: determine the at least one scatter configuration parameter for the X-ray scatter measurement based on the estimated radiation dose to the patient.

17. The processor, The mammography system of claim 1 , further configured to generate a spatially resolved scatter mammogram image based on the received x-ray transmission data and the received x-ray scatter data.

18. The mammography system of claim 17, wherein the spatially resolved scatter mammogram image includes at least one indication based on the spatially resolved X-ray scatter spectrum reconstruction, the at least one indication indicating determined spatially resolved tissue characteristics of the region of interest.

19. The mammography system of claim 17, wherein the processor is further configured to generate a coloring of the spatially resolved scattered mammogram image generated based on the received X-ray transmission data and the received X-ray scattered data, and the coloring is based on the spatially resolved X-ray scattered spectral reconstruction.

20. A method for performing spatially resolved volumetric X-ray scattering tomography mammography, said method comprising: performing radiographic measurements and generating a radiodensity mammogram image of the patient's breast based on the received radiographic data; identifying a region of interest within the patient's breast based on the radiodensity mammogram image; determining scatterometry configuration parameters for X-ray scatterometry measurements of the identified region of interest, the scatterometry configuration parameters including at least one of a position of an X-ray source, positions of a plurality of X-ray detecting elements, dimensions of a collimator opening, X-ray source operating parameters, or positions of a plurality of breast plates; measuring the x-ray scattering of the region of interest; transmitting a second primary x-ray beam from the x-ray source through the collimator to shape the second primary x-ray beam and through the breast of the patient positioned using the plurality of breast plates; modulating scattered x-ray radiation from the second primary x-ray beam interacting with the patient's breast using a coded aperture positioned between the patient's breast and the plurality of x-ray detecting elements; detecting the modulated scattered X-ray radiation using the plurality of X-ray detecting elements; receiving x-ray scatter data representing detected scattered x-ray radiation from the plurality of x-ray detection elements; calculating a spatially resolved x-ray scatter spectrum reconstruction based on the received x-ray scatter data, the received x-ray transmission data, and the determined scatterometry configuration parameters; determining at least one spatially resolved tissue property based on the received x-ray scattering data of the region of interest; and performing the method by

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