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The purpose of this paper is to develop a technique for the construction of a two-compartment anthropomorphic breast phantom specific to an individual patient's pendant breast anatomy. Three-dimensional breast images were acquired on a prototype dedicated breast computed tomography (bCT) scanner as part of an ongoing IRB-approved clinical trial of bCT. The images from the breast of a patient were segmented into adipose and glandular tissue regions and divided into 1.59 mm thick breast sections to correspond to the thickness of polyethylene stock. A computer-controlled water-jet cutting machine was used to cut the outer breast edge and the internal regions corresponding to glandular tissue from the polyethylene. The stack of polyethylene breast segments was encased in a thermoplastic 'skin' and filled with water. Water-filled spaces modeled glandular tissue structures and the surrounding polyethylene modeled the adipose tissue compartment. Utility of the phantom was demonstrated by inserting 200 µm microcalcifications as well as by measuring point dose deposition during bCT scanning. Affine registration of the original patient images with bCT images of the phantom showed similar tissue distribution. Linear profiles through the registered images demonstrated a mean coefficient of determination (r(2)) between grayscale profiles of 0.881. The exponent of the power law describing the anatomical noise power spectrum was identical in the coronal images of the patient's breast and the phantom. Microcalcifications were visualized in the phantom at bCT scanning. The real-time air kerma rate was measured during bCT scanning and fluctuated with breast anatomy. On average, point dose deposition was 7.1% greater than the mean glandular dose. A technique to generate a two-compartment anthropomorphic breast phantom from bCT images has been demonstrated. The phantom is the first, to our knowledge, to accurately model the uncompressed pendant breast and the glandular tissue distribution for a specific patient. The modular design of the phantom allows for studies of a single breast segment and the entire breast volume. Insertion of other devices, materials and tissues of interest into the phantom provide a robust platform for future breast imaging and dosimetry studies.

As new algorithms for microwave imaging emerge, it is important to have standard accurate benchmarking tests. Currently, most researchers use homogeneous phantoms for testing new algorithms. These simple structures lack the heterogeneity of the dielectric properties of human tissue and are inadequate for testing these algorithms for medical imaging. To adequately test breast microwave imaging algorithms, the phantom has to resemble different breast tissues physically and in terms of dielectric properties. We propose a systematic approach in designing phantoms that not only have dielectric properties close to breast tissues but also can be easily shaped to realistic physical models. The approach is based on regression model to match phantom's dielectric properties with the breast tissue dielectric properties found in Lazebnik et al. (2007). However, the methodology proposed here can be used to create phantoms for any tissue type as long asex vivo,in vitro, orin vivotissue dielectric properties are measured and available. Therefore, using this method, accurate benchmarking phantoms for testing emerging microwave imaging algorithms can be developed.

Breast phantom made as combination of paraffin and INTRALIPID™ was tested by use of X-ray classical computed tomography and polarimetric optical tomography. The INTRALIPID™ is a liquid commonly used for simulation breast tissues optical properties but it is useless as X-ray phantom. During our tests we have observed that X-ray tomography allows to recognize a proper placement of INTRALIPID™ inclusions inside paraffin medium but we cannot distinguish density of INTRALIPID™ within each inclusions. On the other hand the polarimetric optical tomography allows to distinguish density of INTRALIPID™ (0%, 10%, 20%) in inclusions but with relatively low accuracy of their placement.

This communication deals with a recently proposed methodology for breast cancer diagnosis. Such a strategy is based on the joint use of microwaves, as a non-invasive and non-toxic tool to probe cancer lesions, and of Magnetic NanoParticles (MNP). These latter are used as a biocompatible contrast agent able to selectively enhance the response of cancerous tissues by modifying their magnetic permeability. Key aspects of the strategy are the possibility to modulate the magnetic response of MNP by using a polarizing magnetic field and the capabilities of avoiding ambiguities in discriminating between cancerous and healthy tissues. This contribution aims at providing a feasibility assessment of this new methodology in quasi realistic conditions. To this purpose, a numerical analysis has been carried out, in which the MNP behavior has been modeled according to the results of an experimental characterization and the imaging problem has been simulated by considering malignant lesions lying into an anthropomorphic 3D breast phantom.

To comprehensively characterize the dosimetric properties of a clinical digital breast tomosynthesis (DBT) system for the acquisition of mammographic and tomosynthesis images.Compressible water-oil mixture phantoms were created and imaged by using the automatic exposure control (AEC) of the Selenia Dimensions system (Hologic, Bedford, Mass) in both DBT and full-field digital mammography (FFDM) mode. Empirical measurements of the x-ray tube output were performed with a dosimeter to measure the air kerma for the range of tube current-exposure time product settings and to develop models of the automatically selected x-ray spectra. A Monte Carlo simulation of the system was developed and used in conjunction with the AEC-chosen settings and spectra models to compute and compare the mean glandular dose (MGD) resulting from both imaging modalities for breasts of varying sizes and glandular compositions.Acquisition of a single craniocaudal view resulted in an MGD ranging from 0.309 to 5.26 mGy in FFDM mode and from 0.657 to 3.52 mGy in DBT mode. For a breast with a compressed thickness of 5.0 cm and a 50% glandular fraction, a DBT acquisition resulted in an only 8% higher MGD than an FFDM acquisition (1.30 and 1.20 mGy, respectively). For a breast with a compressed thickness of 6.0 cm and a 14.3% glandular fraction, a DBT acquisition resulted in an 83% higher MGD than an FFDM acquisition (2.12 and 1.16 mGy, respectively).For two-dimensional-three-dimensional fusion imaging with the Selenia Dimensions system, the MGD for a 5-cm-thick 50% glandular breast is 2.50 mGy, which is less than the Mammography Quality Standards Act limit for a two-view screening mammography study.

Electromagnetic ultra-wideband (UWB) sensing and imaging provide perspectives for early-stage breast cancer detection. This paper deals with practical chal- lenges of real measurements. We present an experimental setup for breast phantom trials based on M-sequence radar technology and short active dipole antennas. It com- bines short impulse responses, appropriate fidelity and very small antenna dimension and allows array construc- tion with sufficient number of antennas around the breast. The basic approach and obtained imaging results are pre- sented. Furthermore, in this extended paper version con- tinuative development steps are described and measure- ment results reflecting specific performance aspects are discussed.

We previously developed a dynamic 4D anthropomorphic breast phantom, which can be used to optimize contrast-based breast imaging systems, accounting for patient variability and contrast kinetics [1]. In this study we aim to compare the performance of contrast-enhanced mammographic and tomosynthesis imaging protocols followed by temporal subtraction and dual-energy subtraction, qualitatively and quantitatively across a couple of patient models. Signal-difference-to-noise ratio (SDNR) is measured for the six paradigms of contrast enhanced, temporally subtracted, and dual-energy subtracted mammography and tomosynthesis and compared. The results show how the performance is more dependent on the breast model in mammography than in tomosynthesis. Also, it is observed that dual-energy subtraction can be beneficial in mammography, whereas it is not advantageous in tomosynthesis. Lastly, the results suggest that temporal subtraction in general outperforms dual-energy subtraction.

Mammographic tissue structure has been shown to exhibit directionality, with a preferred orientation towards the nipple. However, this property is absent in the small-scale tissue model of current breast phantoms. To improve existing breast phantoms, a model for simulating oriented breast tissue has been developed, and has been included into an existing anthropomorphic breast phantom. Within this model, directionality was introduced by filling compartments with binarized power-law noise that was oriented towards the nipple. Mammograms were simulated based on the original and the new directional phantom. Tissue orientation was measured in the simulated mammogram. Visually, the appearance of the enhanced phantom was more realistic. Further, the distribution of the orientation measure computed from the enhanced phantom was more similar to that in actual mammograms. In conclusion, the use of a directional model to simulate fibroglandular tissue greatly improves the realism of the breast phantom.

We investigated the appropriateness of four different mammography phantoms for image quality evaluation in Digital Breast Tomosynthesis (DBT). We tested the CIRS BR3D phantom, the ACR Prototype FFDM Accreditation Phantom, the Penn anthropomorphic breast phantom and the Quart mam/digi EPQC phantom. This work discusses the advantages and shortcomings of each phantom and concludes that none of them, in their current form, can be considered to be adequate as an image quality evaluation phantom for DBT.

Film dosimetry has been applied to measure relative dose distributions in an anthropomorphic polystyrene breast phantom having cork lungs, simulating a radiation therapy treatment with 6 MV opposing tangential beams. Measured relative dose distributions showed good reproducibility (about 1.5%, 1 SD) and good agreement (< 2%) with calculations performed with a three-dimensional treatment planning system. These results demonstrate that film dosimetry is a useful tool for treatment planning verification.

Measurement of a percent glandular tissue composition (%GTC) is important in terms of the estimation of individual patient exposure dose and the prediction of malignancy, and thus a number of reports for estimating %GTC by use of a mammogram have been published. In this study, we propose a method for estimating individual %GTC by use of computed radiography (CR) mammograms. By employing breast-equivalent phantoms that are able to create breast phantom images with various combinations of fat and glandular tissue, as well as the thickness of whole breast, we determined a reference table for converting an each pixel value on CR mammography to the glandular tissue ratio. Therefore, the %GTC for individual breast was estimated by averaging glandular tissue ratio for a whole region. The clinical image data set that consisted of 49 CR mammograms were used for estimating %GTC. A paired comparison method for determining subjective ranking of the degree of breast density was employed in order to demonstrate the validity of our method. The results indicate that the average estimated %GTC was 35.0% (ranged from 12.0% to 67.0%) and they had a increased correlation with the ranking of those obtained by observer test. Therefore, it was suggested that our proposed method would be utilized for estimating the %GTC in objective manner.

This paper investigates the role bandwidth plays in ultra-wideband (UWB) microwave imaging for breast cancer detection. Most UWB microwave imaging systems operate between 3.1–10.6GHz as the FCC has authorised unlicensed use in this spectrum. Whether this is the optimal bandwidth for microwave breast imaging remains an open question. Using signals of different bandwidth and spectrum, this paper provides a computational study using an anatomical realistic breast phantom on the detection and location ability of an imaging algorithm.

Accuracy control of mammography equipment involves more than just equipment management; the proportions of the mammary glands used to obtain appropriate images is also important, as is control of the glandular X-ray dose in accordance with thickness. Methods for evaluating glandular dose include the ACR, EUREF, and IAEA protocols. The aim of this study was to elucidate the differences between the various protocols and to suggest a dose evaluation method suited to Japanese breast thickness. An ionization chamber dosimeter was used for dose measurement, with a 156 phantom used as a breast phantom for the ACR and a PMMA phantom used for the EUREF and IAEA. There were no major differences in the protocols. The AGDs in the breast phantoms recommended HVLs for each protocol but were 25-30% higher in the EUREF and IAEA compared with the ACR, owing to the different breast thicknesses in each case. The IAEA should be regarded as the basic method for implementing optimum accuracy control in Japan, and a 35-mm PMMA should be used to correspond most closely to Japanese breast thickness.

The development and acoustical characterization of a novel agar-based tissue mimicking material for use in training purposes in diagnostic ultrasonography are presented. The phantom described in this study is based on a range of inexpensive, reproducible and non-toxic materials. During the tests, the effect of the physical properties such as temperature and percentage of materials on the sound speed in the fabricated phantom was evaluated. Additionally, the analysis on the results of ultrasound imaging was represented.

In the present study, the radiological visibility of ceramic and polymeric devices implanted in breast phantom was investigated for future applications in brachytherapy. The main goal was to determine the radiological viability of ceramic and polymeric devices in vitro by performing simple radiological diagnostic methods such as conventional X-ray analysis and mammography due to its easy access to the population. The radiological response of ceramic and polymeric devices implanted in breast phantom was determined using conventional X-ray, mammography and CT analysis.

This paper presents experimental study to distinguish between malignant and benign tumors in early breast cancer detection using Ultra Wide Band (UWB) imaging. The contrast between dielectric properties of these two tumor types is the main key. Mainly water contents control the dielectric properties. Breast phantom and tumor are fabricated using pure petroleum jelly and a mixture of wheat flour and water respectively. A complete system including Neural Network (NN) model is developed for experimental investigation. Received UWB signals through the tumor embedded breast phantom are fed into the NN model to train, test and determine the tumor type. The accuracy of the experimental data is about 98.6% and 99.5% for permittivity and conductivity respectively. This leads to determine tumor dielectric properties accurately followed by distinguish between malignant and benign tumors. As malignant tumors need immediate further medical action and removal, this findings could contribute to save precious file in near future.

This paper discusses the development of an artificial heterogeneous breast phantom that emulates the electrical properties of human breast over the ultra wideband frequency range of 3.1GHz to 10.6GHz. The developed breast phantom has a realistic hemispherical shape and dielectric properties which are close to those of the different real breast tissues. This artificial breast phantom is to be used to test the reliability of the microwave imaging systems that are investigated for early breast cancer detection. The measured characteristics of the developed phantom validate its capability to emulate the characteristics of the real breasts.

Outlier due to false peak error (FPE) usually emerges during displacement estimation of ultrasound elastography, for which the performance of the resulted elastogram is degraded evidently. In this paper, a new method to remove the displacement outliers is proposed. The method is carried out in two steps, i.e., outlier detection and replacement. For the first step, the median of local displacement difference is computed and compared with a threshold deduced according to the application parameters such as the maximum tissue strain, the signal-to-noise ratio of the displacement estimation (SNRe), and the dimensions of the local window. If the median is larger than the threshold, the displacement point is deemed an outlier. For the second step, the displacement outlier is replaced with the median of the displacement points in a local region. The results from the experiments with theoretical data contaminated by artificial outliers show that the proposed method is effective in removing the displacement outliers when the outlier points is not more than a reasonable ratio in all the displacement points. Meanwhile, the result of breast phantom experiment further verifies the validity of this method.

In developing a Virtual Reality simulation for learning breast palpation, one of critical aspects is real-time visualization of breast phantom deformation during palpation. Available models are either offline ones using Finite Element Method (FEM) analysis with considering some material parameters of deformable objects; or real-time ones with difficulties of balancing between this consideration and realistic visualization. For visual perception of breast phantom deformation, we used a real-time model with an inside pressure to keep the volume of the breast phantom constant. On a meshed breast phantom, we compared the displacements of vertices governed by the real-time model with those governed by its FEM counterpart for four different distributions of contact force. To satisfy visual perception of breast phantom deformation, we examined the comparison by utilizing the statistical methods of ANOVA and Bland and Altman agreement. The results revealed that the displacements of vertices governed by the real-time model are in agreement with those by its FEM counterpart for each distribution of contact force. This observation indicates the potential of our real-time model for visualizing breast phantom deformation during palpation.

The entrance surface dose (ESD) (skin dose) and its variation due to overlapping radiation fields at mammography have been experimentally investigated on patients during two-view mammography screening examinations of both breasts and on phantoms of silicon gel. Measurements were done using multiple thermoluminescence dosemeters for mapping the variations in absorbed dose at the surface of the breast phantoms. It was found that the total resulting skin dose at the reference point on the breast surface, described in the European Protocol [Zoetelief, Fitzgerald, Leitz and Sabel (European protocol on dosimetry in mammography. EUR 16263 (Luxemburg: EC), 1996)] after multiple exposure of patient's breasts during two-view, four exposures mammography screening examinations is approximately 50 % higher as compared with the skin dose at the same point measured during one single (CC) exposure. The dose distributions on the breast phantom surface were non-uniform and indicated areas of higher doses, which were related to the regions of the superimposed fields on the surface during the examinations. The dosimetric importance of the superposition of X-ray fields on the ESD is discussed.

Analysis of complex imaging tasks requires a phantom that simulates the patient anatomy. We have developed a technique to fabricate 3D physical anthropomorphic breast phantoms for image quality assessment of 2D and 3D breast x-ray imaging systems. The phantom design is based on an existing computer model that can generate breast voxel phantoms of varying size, shape, glandularity, and internal composition. The physical phantom is produced in two steps. First, the computer model of the glandular tissue, skin and Coopers' ligaments is separated into sections. These sections are fabricated by high-resolution rapid prototype printing using a single tissue equivalent material. The adipose tissue regions in the sections are filled using an epoxy-based resin combined with phenolic microspheres. The phantom sections are then stacked. The phantom is provided with an extra section modified to include iodine-enhanced masses. We fabricated a prototype phantom corresponding to a 450 ml breast with 45% dense tissue deformed to represent a 5 cm compressed thickness. The rapid prototype and epoxy based resin phantom materials attenuate x rays similar to 50% glandular tissue and 100% adipose tissue, respectively. The iodinated masses are between 4.0 and 9.6 mm thick and contain 2.5 mg/ml and 5 mg/ml iodine. Digital mammography and digital breast tomosynthesis images of the phantom are qualitatively similar in appearance to clinical images. In summary, a method to fabricate a 3D physical anthropomorphic breast phantom has been developed with known ground truth in the form of a companion voxel phantom. This combined system of physical and computational phantoms allows for both qualitative and quantitative image quality assessment.

To study the effects of overlapping anatomy on microcalcification detection at various incident exposure levels. Images of an anthropomorphic breast phantom (RMI 169) overlapping with simulated microcalcifications ranging from 150 to 212 μm in size placed in two breast density regions, fatty and heterogeneously dense, were acquired with an a-Si/a-Se flat panel based digital mammography system (Selenia) operated with Mo-Mo target/filter combination at 28 kVp. The mammograms were exposed with 20, 30, 40, 60, 80, 120, 160, 240 and 325 mAs for varying the exposure level. A 4-AFC study was performed for evaluation of the detection performance. Four 400×400-pixel images were displayed as 2×2 array on a LCD flat panel based review workstation. One of the four images contained a cluster of five microcalcifications and was randomly placed in one of the four quadrants. A physicist was asked to select the image containing the microcalcifications and to report the number of visible microcalcifications. The fraction of correct responses was computed with two different criteria: (1) the selected images contained one or more microcalcifications, and (2) the selected images contained 4 or 5 visible microcalcifications. The statistical significance of the differences in fractions for different exposure levels and regions was evaluated. The results showed that, if visibility of one or more microcalcifications is required, the fractions of correct responses were 1 for all size groups and most exposure levels in both fatty and heterogeneously dense regions. If a visibility of 80% or more of the microcalcifications was required, the fractions of correct responses significantly decreased in both regions. The results indicated that microcalcification detection in the fatty region appeared to be mainly limited by the quantum noise, and that in the heterogeneously dense region may be limited by both the anatomic noise and the quantum noise.

We have performed spectral analysis of simulated tomosynthesis projections generated using an anthropomorphic software breast phantom Twenty phantoms were generated: ten 450 ml phantoms with 40% glandular fraction and ten 1500 ml phantoms with 20% glandular fraction Simulated mammographic compression and acquisition was performed using monoenergetic ray-tracing ROIs were extracted and the modulus-squared 2D FFT was applied to each ROI to obtain periodograms Radially-averaged periodograms were compared between phantom and clinical images We observed a good agreement between the spectral power law exponents (β) calculated from phantom projections and clinical images.

The design of limited angle tomography systems requires the optimization of various imaging parameters in order to achieve useful as well as reliable results. Algebraic reconstruction techniques, specifically the SART algorithm, have given excellent results in CT and are being actively considered for limited angle commercial applications such as tomosynthesis. In this study, we simulate a range of limited angle scenarios by systematically varying a number of key imaging parameters, and examine the performance of the SART algorithm under these variations. The phantoms used are basic ellipsoids in 2D, yielding analytical projections, and an MR-derived breast phantom in 3D.

In this paper, we aim to acquire simulated mammograms. This simulated data is performed on GATE (Geant4 Application for Tomographic Emission), a platform for simulation based on Monte Carlo methods. On this software, a particular tool, the new CTscanner, is used to simulate the interation between X-ray and tissues. We hope also to demonstrate how the new CTscanner system can be used. The NCAT phantom is used to obtain data, where only the volume of the breast is employed to achieve the simulation. Geometric phantoms are also used for simulation of more simple objects. The parameters for the reproduction of mammograms are introduced accordingly the Siemens Mammomat Inspiration mammography unit, since this is a recent device. The aim of this work is to get simulated mammograms from different angles of the same object, which will allow the access of tri-dimensional reconstruction for Digital Breast Tomosynthesis. We present and discuss the results obtained using the proposed simulations.

The purpose of this study is to report on the new developments and optimizations of the methodology for generation of 3D breast software phantoms. It is an evolution of a previously presented 3D non compressed breast modeling method used for creation of breast models of different size, shape and composition. The new features include improved methodology for generation of realistic mammographic texture, compression simulation of the modeled breasts and algorithms to speed up the breast phantom production. The enhanced breast phantom has been evaluated in the case of mammography. Synthetic images of non compressed and compressed breast models are created by simulated image acquisition module. Evaluation of the mammographic texture was accomplished by comparison with real texture and physicians involved in the visual assessment process. The results demonstrated that the new methodology for breast models creation results in improved realistic synthetic images. Further on, mammographic images of breast phantoms with abnormalities and their compressed version were produced and assessed visually and quantitatively. The preliminary results showed an improved visibility of the microcalcifications in the images obtained with the compressed breast models. The reported methodology for generation of 3D breasts therefore, could serve as a basic tool in research of novel and advanced x-ray breast imaging techniques like dual energy, contrast-phase and diffraction mammography, Cone Beam CT and Digital Tomosynthesis.

Elastography is developed as a quantitative approach to imaging linear elastic properties of tissues to detect suspicious tumors. In this paper a nonlinear elastography method is introduced for reconstruction of complex breast tissue properties. The elastic parameters are estimated by optimally minimizing the difference between the computed forces and experimental measures. A nonlinear adjoint method is derived to calculate the gradient of the objective function, which significantly enhances the numerical efficiency and stability. Simulations are conducted on a three-dimensional heterogeneous breast phantom extracting from real imaging including fatty tissue, glandular tissue, and tumors. An exponential-form of nonlinear material model is applied. The effect of noise is taken into account. Results demonstrate that the proposed nonlinear method opens the door toward nonlinear elastography and provides guidelines for future development and clinical application in breast cancer study.

[1] Using similar techniques to ground penetrating radars, microwave detection of breast tumors is a potential nonionizing and noninvasive alternative to traditional body-imaging techniques. In order to develop an imaging system, the team at Bristol have been working on a number of antenna array prototypes, based around a stacked-patch element, starting with simple pairs of elements and progressing to fully populated planar arrays. As the system commences human subject trials, a curved breast phantom has been developed along with an approximately hemi-spherical conformal array. This contribution will present details of the conformal array design and initial results from this unique experimental imaging system as applied to an anatomically shaped breast phantom.

Analysis of the breast surface deformation during mammographic compression will provide insight into breast tissue elastic properties. Our long term goal is to accurately estimate physical properties of breast tissue for the purpose of realistic deformation simulation. As a first step, we analyzed the acquisition accuracy of the reconstructed breast phantom surface using a non-contact laser scanner. The effect of the acquisition angle and the presence of the transparent compression plate covering the phantom were considered. Comparing 48 phantom surfaces, each reconstructed from 4 scanner images acquired at different positions, we observed an average acquisition error of 1.94 mm for images without the compression plate; the average acquisition error for images with the compression plate was 3.26 mm. Performance of two observers showed little variation.

The quality and realism of simulated images is currently limited by the quality of the digital phantoms used for the simulations. The transition from simple raster based phantoms to more detailed geometric (mesh) based phantoms has the potential to increase the usefulness of the simulated data. A preliminary breast phantom which contains 12 distinct tissue classes along with the tissue properties necessary for the simulation of dynamic positron emission tomography scans was created (activity and attenuation). The phantom contains multiple components which can be separately manipulated, utilizing geometric transformations, to represent populations or a single individual being imaged in multiple positions. A new relational descriptive language is presented which conveys the relationships between individual mesh components. This language, which defines how the individual mesh components are composed into the phantom, aids in phantom development by enabling the addition and removal of components without modification of the other components, and simplifying the definition of complex interfaces. Results obtained when testing the phantom using the SimSET PET/SPECT simulator are very encouraging.

Software breast phantoms offer greater flexibility in generating synthetic breast images compared to physical phantoms. The realism of such generated synthetic images depends on the method for simulating the three-dimensional breast anatomical structures. We present here a novel algorithm for computer simulation of breast anatomy. The algorithm simulates the skin, regions of predominantly adipose tissue and fibro-glandular tissue, and the matrix of adipose tissue compartments and Cooper's ligaments. The simulation approach is based upon a region growing procedure; adipose compartments are grown from a selected set of seed points with different orientation and growth rate. The simulated adipose compartments vary in shape and size similarly to the anatomical breast variation, resulting in much improved phantom realism compared to our previous simulation based on geometric primitives. The proposed simulation also has an improved control over the breast size and glandularity. Our software breast phantom has been used in a number of applications, including breast tomosynthesis and texture analysis optimization.

The IPSM report on the commissioning and routine testing of mammographic x-ray systems recommends that breast dose be specified as the mean dose to the glandular tissues within the breast and gives the size and compositions of a standard breast phantom for the comparison of doses. The dose to this standard breast phantom can be determined by measuring the incident air kerma to a Perspex phantom and applying appropriate multiplicative conversion factors. These conversion factors have been evaluated by Monte Carlo calculations for a wide range of mammographic x-ray spectra. Some factors are provided for a range of breast thicknesses to supplement existing tabulations. Results are also given for equivalent thicknesses of Perspex and breast tissue.

A new technique for producing anthropomorphic radiologic phantoms is described. Information from a patient radiograph is used to design the phantom. Optical densities from a digitized radiograph are converted to thicknesses of a phantom material, with corrections for geometry, x‐ray spectrum, and scatter. Numerically controlled machining techniques are used to transcribe the anatomic details into the phantom material. High spatial frequencies are reproduced separately from low spatial frequencies using photochemical techniques in order to replicate finer details in the phantom. The result is a phantom consisting of a number of overlays. Radiographs of a breast phantom produced using the technique are shown, energy equivalence to attenuation of breast tissue is assessed, and methods of incorporating fine detail and quantitative features in the phantom are suggested.

Tomosynthesis reconstructs 3-dimensional images of an object from a significantly fewer number of projections as compared with that required by computed tomography (CT). A major problem with tomosynthesis is image artifacts associated with the data incompleteness. In this article, we propose a hybrid tomosynthesis approach to achieve higher image quality as compared with competing methods. In this approach, a low-resolution CT scan is followed by a high-resolution tomosynthesis scan. Then, both scans are combined to reconstruct images. To evaluate the image quality of the proposed method, we design a new breast phantom for numerical simulation and physical experiments. The results show that images obtained by our approach are clearly better than those obtained without such a CT scan.

Breast cancer is one of the most common forms of cancer in women. X-ray mammography is the most widely used technique for early detection but has limitations. In this paper, an alternative approach for breast cancer detection using microwave imaging is presented. This is based upon a microwave holographic approach, central to which is the use of a synthetic reference beam. This approach has benefits in terms of simplicity and expense. Experimental results using a breast phantom are included to demonstrate the potential of this approach.

A new breast-shaped compensation filter has been designed and fabricated for breast imaging using our newly built breast imaging (CBCTBI) system, which is able to scan an uncompressed breast with pendant geometry. The shape of this compensation filter is designed based on an average-sized breast phantom. Unlike conventional bow-tie compensation filters, its cross-sectional profile varies along the chest wall-to-nipple direction for better compensation for the shape of a breast. Breast phantoms of three different sizes are used to evaluate the performance of this compensation filter. The reconstruction image quality was studied and compared to that obtained without the compensation filter in place. The uniformity of linear attenuation coefficient and the uniformity of noise distribution are significantly improved, and the contrast-to-noise ratios (CNR) of small lesions near the chest wall are increased as well. Multi-normal image method is used in the reconstruction process to correct compensation flood field and to reduce ring artifacts.

Previous studies have suggested that iodine contrast-enhanced breast tomosynthesis can be helpful in the characterization of suspicious abnormalities. Dual-energy, contrast-enhanced breast tomosynthesis involves acquiring low- and high-energy acquisitions after the administration of the contrast agent, and therefore can simplify the procedure and reduce the effect of patient motion. In this study, a computer simulation is developed for use in investigating optimal parameters for dual-energy, contrast-enhanced breast tomosynthesis. The simulation allows for the selection of various polyenergetic x-ray spectra and x-ray filters, and models x-ray transport through a voxelized breast phantom, as well as signal and noise propagation through an indirect CsI based imager. A compressed breast phantom that models the non-uniform parenchymal structure of the breast is used. Irregular lesions were simulated by using a stochastic growth algorithm. Simulations of dual-energy subtraction, contrast-enhanced breast tomosynthesis show that using x-ray filters to form quasi-monochromatic high- and low-energy spectra above and below the iodine K-edge can substantially reduce background structure, and increase lesion conspicuity as compared to single shot contrast-enhanced BT.

We use a contrast-detail observer study to compare performance of a novel 3D computed mammotomography (CmT) system with a commercially developed full-field digital mammography (FFDM) system. A contrast-detail phantom comprised of uniform acrylic spheres of various diameters was developed and placed in a variety of mediums including uniform water (simulating low contrast lesions within a uniform background), water and acrylic yarn (simulating low contrast lesions with over/under-lying structure), oil only (simulating higher contrast lesions in a uniform background), and oil and acrylic yarn (simulating higher contrast lesions with over/under-lying structure). For CmT, the phantom was placed in a 14.6 cm diameter uncompressed breast phantom and projections acquired using a simple circular orbit, W-target tube, 60 kVp tube potential, 0.05 cm Ce filtration, 4 mAs per projection, and a CsI(Tl) digital x-ray detector. Reconstructions used an iterative OSTR algorithm. For FFDM, the phantom was placed in a 5.3-cm-thick compressed breast phantom. Single CC-view mammograms were acquired using a clinical W-target tube with 50 um Rh filtration, 28 kVp, photo-timed mAs per our clinical mammography operation, and a Selenium-based flat-panel detector (Mammomat Novation, Siemens). Six observers evaluated the images in terms of the number of detectable spheres. FFDM performed significantly better for the low contrast lesions in uniform water background (p

Magnetic resonance electrical impedance tomography (MREIT) has been developed as a new medical imaging modality providing high-resolution conductivity and current density images. This paper is about MREIT of the breast. To show the feasibility of breast MREIT, we carried numerical simulations and breast phantom experiments. We found that an anomaly with 4 mm diameter can be visualized in a reconstructed conductivity image using 5 mA injection current if the SNR of the corresponding MR magnitude image is at least 150. We propose a desirable electrode configuration and show our first experimental results of the breast MREIT. Developing an RF coil for the breast MREIT, we plan to conduct various experimental studies including tissue phantoms.

To evaluate the accuracy of dose calculation algorithms of different planning systems for postoperative tangential radiotherapy in breast cancer. On a CT dataset of an anthropomorphic phantom, a structure set of the left lung, clinical target volume (CTV), planning target volume, heart, and external contour were delineated. The dataset was processed by six radiation oncology centers participating in this multicenter dosimetry project. Conventional plans with two tangential wedged fields were generated in MasterPlan®, Pinnacle®, Eclipse®, TMS®, and PrecisePLAN®. Plan calculations were done using the beam data of local linacs. The dose distributions were verified under local conditions with Gafchromic®-EBT films. In all planning systems, deviations between calculation and measurement were around ±3% in the CTV in the measured plane. Only small areas with deviations of ±5% were detected. Pencil-beam (PB) calculations overestimated the dose inside the lung by up to 23%. Collapsed cone (CC) underestimated the lung dose by up to 6%. CC calculates the dose distribution more accurately than PB. Inside regions with electron disequilibrium, however, the dose is slightly underestimated.

Purpose: To determine the effect of breast CT-derived fibroglandular distributions on glandular dose in mammography. Methods: Previously-reported 3D glandular distributions, obtained from a large cohort of breast CT (bCT) data sets (N=219), were fit to bi-Gaussian functions and used as probability density maps to assign glandular distributions within compressed breast models. Using a conventional mammography geometry, MCNPX was used to simulate monoenergetic normalized glandular dose “DgN(E)” values in compressed phantoms composed of either a homogeneous mixture of glandular and adipose tissue or heterogeneously distributed glandular tissue. The DgN(E) values were weighted by mammographic x-ray spectra to produce polyenergetic DgN (pDgN) values for the homogeneous (pDgNhomo) and heterogeneous (pDgNhetero) tissue compositions. This work quantified the effect of permutations in glandular fraction, phantom size, x-ray technique, and location of glandular distributions on pDgN values. Results: Averaged across all phantom sizes and glandular fractions, pDgNhetero values were 30.1% and 21.6% lower than the pDgNhomo values for the Mo and W x-ray spectra, respectively, when the heterogeneous distributions were centered within the breast phantom. Displacement of the glandular distributions in the superior and inferior directions resulted in pDgNhetero values 5.7% and 49.4% lower than pDgNhomo values, respectively, for Mo x-ray spectra. Lateral displacement of the glandular distributions resulted in no notable difference in pDgN values. Conclusion: This study demonstrates that glandular dose values in mammography are 20 to 30% lower than assumed using the homogeneous approximation resulting from overestimation of glandular tissue at the breast entrance where the dose deposition is higher. The sensitivity analysis also demonstrates that the differences depend on likely perturbations in the glandular distributions. While these results are robust because the glandular distributions are modeled from a large cohort of bCT data sets, future work will focus on improved quantification of the glandular distributions based on breast size and glandular fraction.

This poster is a case presentation of a woman who was recalled from breast screening with suspicious microcalcifications. Follow-up mammograms revealed that it had been an artefact on the skin surface. The cause of this artefact was unknown and this poster attempts to identify a product that may have caused this calcific-like artefact. Previous research [1,2] highlights the potential problems associated with the use of deodorants and antiperspirants on mammographic interpretation. These studies demonstrate the association of the use of underarm deodorants with calcific-like artefacts. This poster not only examines deodorant as a possible source of the artefact, but also identifies other products as probable causes. Five products in total were used: stick deodorant, talc, body scrub, paint and body glitter. Samples of each of these were individually X-rayed using an anthropomorphic breast phantom. The subsequent films were compared with the original X-ray and one of the products was identified as the most probable cause of the artefact. As a result of this research, products not previously considered as potential causes of artefacts were identified. Our results are presented in a light-hearted format.

To prospectively evaluate ultrasonographic (US) lesion detection and characterization in a breast phantom by potential investigators in a screening US protocol, American College of Radiology Imaging Network (ACRIN) 6666.National Cancer Institute Cancer Experimental Therapeutic Protocol review and ACRIN internal institutional review board approved the protocol; potential investigators were informed of the study purpose prior to participation. Six equivalent anthropomorphic phantoms were prepared with 17 masses (2-10 mm in mean diameter) in different locations at different depths. Sixty-six investigators, experienced in breast US, from 23 institutions scanned a phantom with high-frequency linear-array transducers (12-5 MHz). Lesion location, diameters, echogenicity, shape, and posterior features were recorded. Reader-specific phantom maps were generated and compared with known lesion locations and features. Results from 64 observers could be analyzed and were masked to investigator identity. Agreement on US features was measured with kappa statistics. A generalized linear model generated log relative risks for detection rates as a function of lesion diameter, depth, and features.Of 17 lesions, a median of 14 (82%) were detected (range, 9-16), and 86% of observers detected at least 12 lesions. Of 1088 potential detections, 861 (79.1%) were made. Among 5-10-mm lesions, 499 (97.5%) of 512 detections were made (excluding a 6-mm "skin" lesion seen by only seven observers [11%]). One 4-mm mass was seen by 53 observers (83%). Among 3-mm lesions, 274 (71.4%) of 384 detections were made. One 2-mm lesion was seen by 28 (44%) observers. Relative risk of detection decreased to 0.55 (95% confidence interval: 0.51, 0.59) for each centimeter increase in lesion depth. Agreement was slight for lesion shape (kappa=0.14), substantial for echogenicity (kappa=0.61), and moderate for posterior features (kappa=0.45). Feature description errors were common for 2-4-mm lesions; only 33% of 3-mm anechoic masses were so characterized. Among eight 6-10-mm lesions, investigators erred in feature description of a median of 1 lesion (mean, 1.3; range, 0-4).US detection and description of lesions in a breast phantom were highly consistent for lesions 5-10 mm in diameter; those smaller than 5 mm were less reliably identified or characterized by experienced investigators.

We present a new medical imaging technique for breast imaging, breast MREIT, in which magnetic resonance electrical impedance tomography (MREIT) is utilized to get high-resolution conductivity and current density images of the breast. In this work, we introduce the basic imaging setup of the breast MREIT technique with an investigation of four different imaging configurations of current-injection electrode positions and pathways through computer simulation studies. Utilizing the preliminary findings of a best breast MREIT configuration, additional numerical simulation studies have been carried out to validate breast MREIT at different levels of SNR. Finally, we have performed an experimental validation with a breast phantom on a 3.0 T MREIT system. The presented results strongly suggest that breast MREIT with careful imaging setups could be a potential imaging technique for human breast which may lead to early detection of breast cancer via improved differentiation of cancerous tissues in high-resolution conductivity images.

This paper presents a patient-specific algorithm for estimating the complete 3-D surface of the breast using recorded backscatter signals. The approach combines a procedure for estimating a finite set of points on the surface of the breast with a surface-fitting procedure tailored for this breast imaging application. The accuracy of this approach using backscatter signals computed from an anatomically realistic numerical breast phantom is demonstrated. Comparisons between the estimated surface and the actual surface of the phantom show excellent agreement.

Ultrasound computer tomography (USCT) is an imaging method capable of producing volume images with sub-millimeter resolution and high image quality. The long term goal of the system under construction is 3D imaging for early breast cancer diagnosis. In this paper the first images of a clinical breast phantom are presented and discussed in respect to further modifications of our system

We are developing an analytic breast phantom that allows for quantitative comparison of reconstruction algorithms for digital breast tomosynthesis. The phantom consists of simple shapes and aims at capturing the main features of the breast. Projection data can be computed analytically. We present volumes reconstructed from the phantom data using the filtered backprojection, expectation maximization and total variation algorithms. Our results indicate that the TV algorithm achieves highest contrast for mass lesions and best in-depth resolution.

Objectives: To determine if movement external to the patient occurring during mammography may be a source of image blur. Methods: Four mammography machines with seven flexible and nine fixed paddles were evaluated. In the first stage, movement at the paddle was measured mechanically using two calibrated linear potentiometers. A deformable breast phantom was used to mimic a female breast. For each paddle, the movement in millimeters and change in compression force in Newton was recorded at 0.5 and 1 second intervals respectively for 40 seconds with the phantom in an initially compressed state under a load of 80N. In the second stage, clinical audit on 28 females was conducted on one mammography machine with the 18x24cm and 24x29cm flexible paddles. Results: Movement at the paddle followed an exponential decay with a settling period of approximately 40 seconds. The compression force readings for both fixed and flexible paddles decreased exponentially with time while fixed paddles have a larger drop in compression force than flexible paddles. There is a linear relationship between movement at the paddle and change in compression force. Conclusions: Movement measured at the paddle during an exposure can be represented by a second order system. The amount of extra-patient movement during the actual exposure can be estimated using the linear relationship between movement at the paddle and the change in compression force. Advances in knowledge: This research provides a possible explanation to mammography image blurring caused by extra patient movement and proposes a theoretical model to analyze the movement.

The aim of this study is to evaluate the incident air kerma (INAK) and the mean glandular dose (MGD) during mammography in Recife, North-east Brazil. The study was performed in three institutions: a private clinic (A), a public hospital (B) and a private hospital (C). The incident air kerma to mammography procedures were estimated using a standard breast phantom and the patient MGD, evaluated in the units B and C, was performed using the calibration of output method. This method involves the recording of the patient exposure parameters (kVp, mAs, filter) and the measurement of these parameters of the incident air kerma using a calibrated ionisation chamber. The results obtained showed that INAK for the standard breast phantom, in the institutions A, B and C, were 18.2, 9.4 and 8.5 mGy, respectively. The results of patient MGD values ranged from 0.23 to 7.46 mGy per film, and the MGD values per woman were between 8.23 and 40.6 mGy for the C institution and between 1.50 and 18.78 mGy for the B institution.