Phase-contrast Mammography Research Articles

Phantom-based comparison of conventional versus phase-contrast mammography for LCD soft-copy diagnosis

Liquid crystal display (LCD) of mammograms provides soft-copy results that differ in conventional and phase contrast mammography (PCM). PCM potentially offers the highest quality of sharpness and graininess, an edge emphasis effect on the object, and the highest image resolution. However, when the image is displayed on an LCD, the resolution depends on the pixel pitch and the PCM image data must be diminished. We investigated the observed effect on spatial resolution and contrast when conventional or phase contrast mammograms are viewed on an LCD. Using the tissue-equivalent phantom (Model 1011A), a conventional mammogram and a magnification radiography image were obtained with a PCM system. This phantom contains simulated fibers, microcalcifications, and masses. The PCM image was reduced 1/1.75 to render it consistent with life size mammography using the nearest neighbor, bilinear, and bicubic interpolation methods. The images were displayed on a five million (5M)-pixel LCD with 100% magnification. Ten mammography technicians observed the reduction images displayed on LCDs and reported their results. In the detectability of the microcalcifications, there was no significant difference between conventional mammograms and reduced PCM images. Regarding fibers and masses, detectability using reduced images was higher than those of conventional images. The detectability using images reduced by the nearest-neighbor method was lower than those of images reduced by two other interpolation methods. Bilinear interpolation was affected by the smoothing effect, while CNR was increased. In addition, since the noise of PCM image was reduced by an air gap effect, high detectability of key image features was found. Soft-copy display of phase-contrast mammograms is feasible with LCDs, while detectability of fibers and masses was best with bilinear interpolation and use of an air gap.

Abstract P4-03-06: Non-invasive classification of microcalcifications by the use of X-ray phase contrast mammography as a novel tool in breast diagnostics

Abstract Purpose: Phase-contrast and scattering-based x-ray imaging are known to provide additional and complementary information to conventional, absorption-based methods. The goal of this study is to evaluate this method to distinguish between benign and malignant microcalcifications with the benefit to increase accuracy of early breast cancer diagnosis. Phase-contrast mammography has been shown to increase image quality of native breast samples when compared to conventional mammography. Two major types of microcalcifications are found within breast tissue. Type I consist of calcium oxalate dehydrate and type II microcalcifications are composed of calcium phosphates. Type I is seen most frequently in benign lesions whereas type II is indicative for proliferative lesions, including carcinomas. Phase contrast mammography is shown here to distinguish between the two types of microcalcifications and therefore indicates a step forward to improve early breast cancer diagnosis. Material and Methods: Freshly dissected breast specimens (n = 50) were imaged using a Talbot-Lau interferometer equipped with a conventional x-ray tube; the interferometer was operated at the fifth Talbot distance, tube voltage of 40 kVp with mean energy of 28 keV, and current of 25 mA. The device simultaneously recorded absorption, differential phase and small-angle scattering signals. These quantities were combined into novel, high-frequency-enhanced radiographic images. Histopathological analysis was performed and regions of interests correlated with the findings of phase contrast mammography. Results: Our novel imaging approach yields complementary and otherwise inaccessible information on electron density distribution and small-angle scattering power of the sample at microscopic scale. Recently we generated the world's first phase contrast mammograms of native, not-fixed human whole breast samples. Our results indicate the superiority of the new technique with respect to image quality and lesion conspicuity. A clinical reader study is currently carried out. Exploiting the multiple, complementary information obtained by grating-based interferometry, we are able to classify microcalcifications by a non-invasive technique within the clinical environment. By considering the small-angle scattering signal as a complement to the absorption signal, our method can analyze the differences in the attenuation coefficient as well as in the crystal structure of the microcalcifications. Further, the scattering signal is used to decouple the thickness parameter. We demonstrate that type I and type II microcalcifications give opposite absorption and scattering signals and in addition the small-angle scattering signal helps to determine the type of microcalcification. Conclusions: The potential clinical significance of phase-contrast enhanced mammography has been evaluated by our team. This technique yields improved diagnostic capabilities when compared with conventional mammography, can provide superior contrast, inaccessible and complementary information, and potentially also reduce dose deposition. The non-invasive classification of microcalcifications is an important step toward early diagnosis and differentiation of breast lesions. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-03-06.

Application of Synchrotron Radiation in Mammography

Recent and emerging applications of synchrotron radiation for mammography have been reviewed and their suitability and future perspectives in diagnostic mammography have been highlighted. Scientific literature and patents review have been accomplished for the last fifteen years in the field of mammography with synchrotron radiation. Phase contrast mammography, k-edge mammography, three-dimensional (3D) mammography, like breast computed tomography and tomosynthesis are amongst the most anticipating applications of synchrotron radiation for mammography. The currently running synchrotron radiation clinical program in mammography, at the SYRMEP beamline at ELETTRA (Trieste) demonstrates mammograms with a high spatial resolution and enhanced features contrast at mean glandular dose, comparable with the one in conventional mammography, revealing the potential of this technique in early detection of breast cancer. Mammograms obtained with diffraction enhanced imaging are characterised with high spatial resolution and excellent visibility of thin collagen strands. Thus, this imaging technique may be used for morphological studies of breast tissues. Efforts are also directed towards realisation of 3D techniques with synchrotron beams. Initial results with breast tissue samples demonstrate potential of tissue differentiation, breast structure separation in depth and clear cancer architecture. The development of new high resolution, low dose and multi-slice detectors, image acquisition protocols and image reconstruction techniques are some of the goals to be achieved towards the implementation of high resolution fullthickness 3D breast imaging. The implementation of the discussed mammographic applications with synchrotron radiation in routine clinical practice, however, faces practical problems such as the large size and very high cost of the synchrotron facilities. It is expected the exploitation of novel more economic synchrotron compact radiation sources to reduce this cost and result in more intensive use of the mammography modalities with synchrotron radiation, specifically in clarifying the ambiguity of the traditional x-ray mammography examinations. Keywords: Breast computed tomography, breast tomosynthesis, compact light sources, computed tomography of diffraction enhanced imaging, detectors for synchrotron radiation, diffraction enhanced imaging, inline phase contrast, k-edge subtraction imaging, morphological studies, phase contrast mammography, reconstruction techniques, synchrotron radiation, x-ray mammography.

First application of computed radiology to mammography with synchrotron radiation

The aim of this study was to evaluate the feasibility of phase-contrast mammography with synchrotron radiation using a high-resolution computed radiology (CR) system devoted to mammography. The study was performed at the Synchrotron Radiation for Medical Physics (SYRMEP) beamline of the Elettra synchrotron radiation (SR) facility in Trieste (Italy); X-ray beams were in the range 16-22 keV with a high degree of monochromaticity and spatial coherence. The CR system evaluated is the FCR Profect CS by Fujifilm Global. The first images were obtained from test objects and surgical breast specimens. Images obtained using SR and both screen-film and the CR system were compared with images of the same samples acquired with digital mammography equipment. In view of the good quality of the results obtained, the CR system was used in two mammographic examinations with SR. Images acquired using SR and both screen-film and CR were obtained with the same level of delivered dose. Image quality obtained with CR was similar or superior to that of screen-film images. Moreover, the digital images obtained with SR were always better than those acquired using the digital mammography system. Phase-contrast mammography with SR using the studied CR system is a feasible option.

Adaptation of a clustered lumpy background model for task‐based image quality assessment in x‐ray phase‐contrast mammography

Since the introduction of clinical x-ray phase-contrast mammography (PCM), a technique that exploits refractive-index variations to create edge enhancement at tissue boundaries, a number of optimization studies employing physical image-quality metrics have been performed. Ideally, task-based assessment of PCM would have been conducted with human readers. These studies have been limited, however, in part due to the large parameter-space of PCM system configurations and the difficulty of employing expert readers for large-scale studies. It has been proposed that numerical observers can be used to approximate the statistical performance of human readers, thus enabling the study of task-based performance over a large parameter-space. Methods are presented for task-based image quality assessment of PCM images with a numerical observer, the most significant of which is an adapted lumpy background from the conventional mammography literature that accounts for the unique wavefield propagation physics of PCM image formation and will be used with a numerical observer to assess image quality. These methods are demonstrated by performing a PCM task-based image quality study using a numerical observer. This study employs a signal-known-exactly, background-known-statistically Bayesian ideal observer method to assess the detectability of a calcification object in PCM images when the anode spot size and calcification diameter are varied. The first realistic model for the structured background in PCM images has been introduced. A numerical study demonstrating the use of this background model has compared PCM and conventional mammography detection of calcification objects. The study data confirm the strong PCM calcification detectability dependence on anode spot size. These data can be used to balance the trade-off between enhanced image quality and the potential for motion artifacts that comes with use of a reduced spot size and increased exposure time. A method has been presented for the incorporation of structured breast background data into task-based numerical observer assessment of PCM images. The method adapts conventional background simulation techniques to the wavefield propagation physics necessary for PCM imaging. This method is demonstrated with a simple detection task.

The First Analysis and Clinical Evaluation of Native Breast Tissue Using Differential Phase-Contrast Mammography

Phase-contrast and scattering-based x-ray imaging are known to provide additional and complementary information to conventional, absorption-based methods, and therefore have the potential to play a crucial role in medical diagnostics. We report on the first mammographic investigation of 5 native, that is, freshly dissected, breasts carried out with a grating interferometer and a conventional x-ray tube source. Four patients in this study had histopathologically proven invasive breast cancer. One male patient, without the presence of any malignant formations within the resected breast, was included as a control specimen. We used a Talbot-Lau grating setup installed on a conventional, low-brilliance x-ray source; the interferometer operated at the fifth Talbot distance, at a tube voltage of 40 kVp with mean energy of 28 keV, and at a current of 25 mA. The device simultaneously recorded absorption, differential phase and small-angle scattering signals from the native breast tissue. These quantities were then combined into novel color- and high-frequency-enhanced radiographic images. Presurgical images (conventional mammography, ultrasonography, and magnetic resonance imaging) supported the findings and clinical relevance was verified. Our approach yields complementary and otherwise inaccessible information on the electron density distribution and the small-angle scattering power of the sample at the microscopic scale. This information can be used to potentially answer clinically relevant, yet unresolved questions such as unequivocally discerning between malignant and premalignant changes and postoperative scars and distinguishing cancer-invaded regions within healthy tissue. We present the first ex vivo images of fresh, native breast tissue obtained from mastectomy specimens using grating interferometry. This technique yields improved diagnostic capabilities when compared with conventional mammography, especially when discerning the type of malignant conversions and their breadth within normal breast tissue. These promising results advance us toward the ultimate goal, using grating interferometry in vivo on humans in a clinical setting.

SU‐E‐I‐144: Radiation Dose Reduction in Monochromatic Phase Contrast X‐Ray Mammography Using Equally Sloped Tomography

Purpose: In mammography, while maintaining the image quality, it is necessary to keep the delivered dose as low as possible since breast is a highly radiosensitive organ. Monochromatic phase contrast X‐ray mammography has shown its potential at higher sensitivity and lower impact in terms of dose delivery compared to absorption based diagnostic X‐ray mammography. An exact Fourier‐based iterative technique termed Equally Sloped Tomography(EST) has been newly developed and implemented on it. Using this technique, we conducted a series of comparative experiments to explore the further more radiation dose reduction in phase contrast mammography through reduction of projection numbers. Methods: Experiment took place at the biomedical beamline at ESRF(ID17). Full Human breasts samples were fixed in 4% formalin solution. Planar imaging and Computed Tomography(CT) modalities were combined to PCI techniques at 60KeV and using a 2kx2k taper optics CCD detector(45 micron pixel). The number of projections scanned was 2000 and digitally removed to 512 for reconstructions. Comparison reconstructions were produced by Filtered‐Back Projection(FBP) with a standard uncropped‐ramp filter. To optimize the result, Non‐local‐means regularization was applied for post‐processing in both cases. Results: Compared to the FBP reconstruction using 2000 projections, EST using 512 projections has comparable SNRs and CNRs, no obvious contrast degradation is observed between tumor and normal glandular tissue. In addition, the collagen exhibit similar visibility. Conclusions: Our results indicate that in the phase contrast mammography, EST technique can reduce the dose up to 50%∼75% by reducing number of projections, while images have comparable quality as the full dose FBP reconstruction. Furthermore, it makes the acquisition time 2∼4 times faster, which is important in in‐vivo imaging. The main reason for this is that EST is an exact Fourier‐based iterative algorithm that can incorporate different physical and mathematical constraints. It is always guided towards a lowest‐possible noisy state while keeping strictly consistent with measurements.Research sponsored by UC Discovery / TomoSoft Technologies Grant #ITL07‐10166.

Phase-Contrast Mammography at the SYRMEP Beamline of Elettra

At the SYnchrotron Radiation for MEdical Physics (SYRMEP) beamline of Elettra, a widespread research activity in bio-medical imaging has been developed since 1997 [1]. The core program carried out by the SYRMEP research team concerns the use of synchrotron radiation (SR) for mammography in the effort of improving image diagnostic quality innovating the imaging technique and the detection system.

Performance analysis of the attenuation-partition based iterative phase retrieval algorithm for in-line phase-contrast imaging

The phase retrieval is an important task in x-ray phase contrast imaging. The robustness of phase retrieval is especially important for potential medical imaging applications such as phase contrast mammography. Recently the authors developed an iterative phase retrieval algorithm, the attenuation-partition based algorithm, for the phase retrieval in inline phase-contrast imaging [1]. Applied to experimental images, the algorithm was proven to be fast and robust. However, a quantitative analysis of the performance of this new algorithm is desirable. In this work, we systematically compared the performance of this algorithm with other two widely used phase retrieval algorithms, namely the Gerchberg-Saxton (GS) algorithm and the Transport of Intensity Equation (TIE) algorithm. The systematical comparison is conducted by analyzing phase retrieval performances with a digital breast specimen model. We show that the proposed algorithm converges faster than the GS algorithm in the Fresnel diffraction regime, and is more robust against image noise than the TIE algorithm. These results suggest the significance of the proposed algorithm for future medical applications with the x-ray phase contrast imaging technique.

A theoretical study on phase‐contrast mammography with Thomson‐scattering x‐ray sources

The x-ray transmitted beam from any material/tissue depends on the complex refractive index (n= 1-delta+ibeta), where delta is responsible for the phase shift and beta is for the beam attenuation. Although for human tissues, the delta cross section is about 1000 times greater than the beta ones in the x-ray energy range from 10 to 150 keV, the gain in breast tumor visualization of phase-contrast mammography (PCM) with respect to absorption contact imaging (AI) is limited by the maximum dose that can be delivered to the patient. Moreover, in-line PC imaging (PCI) is the simplest experimental mode among all available x-ray PCI techniques since no optics are needed. The latter is a fundamental requirement in order to transfer the results of laboratory research into hospitals. Alternative to synchrotron radiation sources, the implementation of relativistic Thomson-scattering (TS) x-ray sources is particularly suitable for hospital use because of their high peak brightness within a relatively compact and affordable system. In this work, the possibility to realize PCM using a TS source in a hospital environment is studied, accounting for the effect of a finite deliverable dose on the PC visibility enhancement with respect to AI. The contrast-to-noise ratio of tumor-tissue lesions in PCM has been studied on the bases of a recent theoretical model, describing image contrast formation by means of both wave-optical theory and the mutual coherence formalism. The latter is used to describe the evolution, during wave propagation, of the coherence of the wave field emitted by a TS source. The contrast-to-noise ratio for both PCI and AI has been analyzed in terms of tumor size, beam energy, detector, and source distances, studying optimal conditions for performing PCM. Regarding other relevant factors which could influence "tumor" visibility, the authors have assumed simplified conditions such as a spherical shape description of the tumor inclusion, a constant surrounding background, ideal conditions for the calculus of the contrast-to-noise ratio. The results show the possibility to enhance with PCI the signal-to-noise ratio for features in the submillimeter scale. This finding could give PCM a great advantage with respect to AI, opening the possibility to decrease the number of wrong diagnoses before histological exams. The results agree with experimental evidences obtained by Dreossi et al. [D. Dreossi et al., "The mammography project at the SYRMEP beamline," Eur. J. Radiol. 68, S58-S62 (2008)] with real PCM using synchrotron radiation. The challenging characteristics of TS sources, suitable for PCM, should be fluxes of at least 10(11) photons/s emitted by very small sources of about 10 microm, together with moderate energy spreads (less than 10%) in order to realize both sufficient spatial coherence and enough fluence on the patient, collecting images in reasonable exposure times. These fluxes will be achieved by next generation TS sources which are already under development.

Evaluation of computer-aided detection of lesions in mammograms obtained with a digital phase-contrast mammography system

A computer-aided detection (CAD) system was evaluated for its ability to detect microcalcifications and masses on images obtained with a digital phase-contrast mammography (PCM) system, a system characterised by the sharp images provided by phase contrast and by the high resolution of 25-μm-pixel mammograms. Fifty abnormal and 50 normal mammograms were collected from about 3,500 mammograms and printed on film for reading on a light box. Seven qualified radiologists participated in an observer study based on receiver operating characteristic (ROC) analysis. The average of the areas under ROC curve (AUC) values for the ROC analysis with and without CAD were 0.927 and 0.897 respectively (P = 0.015). The AUC values improved from 0.840 to 0.888 for microcalcifications (P = 0.034) and from 0.947 to 0.962 for masses (P = 0.025) respectively. The application of CAD to the PCM system is a promising approach for the detection of breast cancer in its early stages.

Theoretical considerations for X-ray phase contrast mammography by Thomson source

The advent, in the near future, of compact X-ray sources like Thomson Back-Scattering (TBS) will allow the clinical application of advanced X-ray imaging techniques, such as phase contrast, with higher sensitivity and lower impact in terms of dose delivery. In this work, we theoretically investigated the possibility of using such sources for phase contrast imaging of micro-calcifications included in a breast tissue. In our study we analyzed the phase and amplitude distribution of the TBS source and we showed that this source can be used for phase contrast imaging since the source coherence at the sample position is sufficiently high for achieving good contrast and micrometer spatial resolution. Indeed the spatial coherence of a TBS source is closer to that of a synchrotron radiation source, and much better than that of a laboratory source. Moreover, we showed the advantages of phase imaging with respect to standard absorption imaging, in the specific case of micro-calcifications detection.

Visibility of tumor-like details in inline phase contrast mammography using quasimonochromatic X-ray sources

A new generation of quasimonochromatic high-flux X-ray sources, based on the X-ray radiation produced through Compton scattering between an electron beam and a laser beam, is under development. One of the possible applications of this source is inline phase contrast mammography, based on the observation of the edge-enhancement effect that can be observed at the border of structures inside the breast in images produced using a partially or totally coherent X-ray beam. In this work we present the results of a set of simulations of inline phase contrast mammography using typical inverse Compton scattering sources parameters. The simulated sample was a tumour-like mass having spherical shape, diameter between 200 μm and 5 mm, placed inside a breast-like matrix, 4 cm thick, and a standard composition of 50% glandular tissue and 50% adipose tissue. We discuss the minimum requirements for mammography using inverse Compton scattering sources and we discuss how the working parameters of the experimental setup (focal spot size, source–object distance, object–detector distance, detector point spread function, mean energy, energy bandwidth) affect the image quality, and specifically the edge-enhancement visibility. In particular, we show that the energy bandwidth does not significantly affect the visibility up to several keV. On the other hand, the edge-enhancement visibility depends substantially on other parameters such as source–object distance and detector point spread function.

Investigation of physical image characteristics and phenomenon of edge enhancement by phase contrast using equipment typical for mammography

A technique called phase contrast mammography (PCM) has only recently been applied in clinical examination. In this application, PCM images are acquired at a 1.75 x magnification using an x-ray tube for clinical use, and then reduced to the real size of the object by image processing. The images showed enhanced object edges; reportedly, this enhancement occurred because of the refraction of x rays through a cylindrical object. The authors measured the physical image characteristics of PCM to compare the image characteristics of PCM with those of conventional mammography. More specifically, they measured the object-edge-response characteristics and the noise characteristics in the spatial frequency domain. The results revealed that the edge-response characteristics of PCM outperformed those of conventional mammography. In addition, the characteristics changed with the object-placement conditions and the object shapes. The noise characteristics of PCM were better than those of conventional mammography. Subsequently, to verify why object edges were enhanced in PCM images, the authors simulated image profiles that would be obtained if the x rays were refracted and totally reflected by using not only a cylindrical substance but also a planar substance as the object. So, they confirmed that the object edges in PCM images were enhanced because x rays were refracted irrespective of the object shapes. Further, they found that the edge enhancements depended on the object shapes and positions. It was also proposed that the larger magnification than 1.75 in the commercialized system might be more suitable for PCM. Finally, the authors investigated phase-contrast effects to breast tissues by the simulation and demonstrated that PCM would be helpful in the diagnoses of mammography.

The mammography project at the SYRMEP beamline

A clinical program for X-ray phase contrast (PhC) mammography with synchrotron radiation (SR) has been started in March 2006 at the SYRMEP beamline of Elettra, the SR facility in Trieste, Italy. The original beamline layout has been modified substantially and a clinical facility has been realized. In order to fulfill all security requirements, dedicated systems have been designed and implemented, following redundancy criteria and “fail safe” philosophy. Planar radiographic images are obtained by scanning simultaneously the patient and the detector through the stationary and laminar SR beam. In this first phase of the project a commercial screen-film system has been used as image receptor. Upon approval by the respective authorities, the mammography program is about half way to conclusion. Up to now about 50 patients have been examined. The patients are volunteers recruited by the radiologist after conventional examinations at the hospital resulted in an uncertain diagnosis. As an example one case of PhC SR mammography is shown and compared to conventional digital mammography. Preliminary analysis shows the high diagnostic quality of the PhC SR images that were acquired with equal or less delivered dose compared to the conventional ones.

Advantages of magnification in digital phase-contrast mammography using a practical X-ray tube

Phase-contrast imaging with a practical cone-beam X-ray tube has been realized for clinical use in digital mammography using computed radiography (CR). To perform phase-contrast imaging, the X-ray detector must be distanced from an object so that the phase-contrast image achieves magnification; in a mammography unit dedicated to phase-contrast imaging, the magnification ratio is 1.75. When using an X-ray tube with a 0.1-mm focal spot, it appears that the penumbra in magnification blurs both projected images and the phase contrast, which generates an edge effect. However, where the sampling pitch of the CR plate is 43.75 μm, the blur stretches the width of the phase contrast so that unit pixels in the detector can capture it. Note that the width of an ideal phase contrast using an X-ray point source results in a phase contrast too narrow for detection with CR. In addition to phase contrast improving image quality, a re-scaling effect increases image sharpness in magnification. Further, image noise induced by magnification can be reduced during printing to photothermographic dry film by demagnifying the digital output image to the original image size. After demagnification by 1/1.75 from 43.75 μm in image acquisition, a 25-μm pixel size of the output image is obtained so that the spatial resolution matches that of conventional screen-film mammography. In this paper, such technical advantages of magnification in digital phase-contrast mammography are reviewed, and the image quality of phase-contrast images is discussed in light of diagnostic requirements in detecting breast cancer.

Digital Mammography: Clinical Implementation and Clinical Trials

Attenuation-based tomosynthesis has proven to successfully resolve the glandular tissue overlap present in mammography. However, the ability of tomosynthesis to differentiate tumorous and glandular tissue remains limited, due to the small differences in X-ray attenuation in breast tissue. One possibility to overcome this limitation and to further increase the diagnostic value of tomosynthesis exams, is the application of recently developed grating-based phase-contrast methods, which provide complementary information on the phase shift and the local scattering power of the sample. In this study, we report on first phase-contrast breast tomosynthesis results of a mastectomy sample slice with an invasive ductal carcinoma.A slice of a mastectomy sample with histologically proven invasive ductal cancer was imaged at the synchrotron radiation source ESRF (Grenoble, France). We used a two-grating interferometer setup at the ninth fractional Talbot distance and with an X-ray energy of 23 keV. In grating interferometry absorption, differential phase, and scattering images are recorded simultaneously. The tomosynthesis scan comprises 61 projections. Multimodal tomosynthesis results were reconstructed using a standard filtered back-projection approach. Our findings are supported by a comparison of tomographic views to histopathology.Phase-contrast tomosynthesis combines the advantage of improved soft-tissue discrimination in phase-contrast imaging with the ability of tomosynthesis to provide a third dimension so that improved feature visibility is not hampered by superposition artifacts. Our results indicate superior diagnostic value due to the depth resolution supplied in tomosynthesis imaging; a region of necrotic tissue that is obscured in a projection image can clearly be depicted in one single tomosynthesis slice. Compared to absorption tomosynthesis alone, soft tissue contrast is significantly enhanced in phase-contrast tomosynthesis views, where fibrous structures are clearly visible.In this article we present the first proof-of-principle grating-based phase-contrast tomosynthesis of a mastectomy sample section. A comparison of conventional attenuation with phase-contrast and dark-field tomosynthesis indicates that complementary information from three signals yields an increase in diagnostic value, which is verified in a comparison of our results to histological sections of the sample. As grating-based phase-contrast mammography efficiently works with conventional lab sources, our benchmark results indicate the potential benefit of translating phase-contrast tomosynthesis into a clinical setting.

The Principle and Images of Phase-Contrast Mammography

The Principle and Images of Phase-Contrast Mammography

The First Trial of Phase Contrast Imaging for Digital Full-Field Mammography Using a Practical Molybdenum X-Ray Tube

The image quality of a newly developed full-field digital phase contrast mammography (PCM) system and of a conventional screen-film (SF) mammography system were compared via images of a phantom and receiver operating characteristic (ROC) analysis of clinical images. Magnified (1.75X) PCM images were scanned (sampling rate, 43.75 microm) and then reduced to original-sized, 25-micron pixel images printed on photothermographic film. Along with corresponding SF images, the phantom images were evaluated subjectively, and the clinical images of 38 patients were subjected to ROC analysis of mass and microcalcification. In the image quality of a phantom, the PCM exceeded the SF. In both mass and microcalcification, the ROC analysis Az values of the PCM clinical images surpassed those of the SF images. The PCM provides better images than the SF. Clinical trials suggest superior detection of both mass and microcalcification by full-field digital PCM over conventional SF mammography.

Spot Compression in Phase Contrast Mammography

Spot Compression in Phase Contrast Mammography